scholarly journals Efeito do lipopolissacarídio bacteriano sobre o esvaziamento gástrico de ratos: avaliação do pré-tratamento com Nw-nitro-L-arginine methyl ester (L-NAME)

2006 ◽  
Vol 43 (3) ◽  
pp. 229-232
Author(s):  
Edgard Ferro Collares ◽  
Adriana Mendes Vinagre
Keyword(s):  
Methyl Ester ◽  
Specific Pathogen Free ◽  
Specific Pathogen ◽  
Per Se ◽  
Óxido Nítrico

RACIONAL: Há evidências de que o óxido nítrico participa do mecanismo de retardo do esvaziamento gástrico determinado pelo lipopolissacarídio bacteriano. OBJETIVO: Avaliar o efeito do pré-tratamento com Nw-nitro-L-arginine methyl ester, um inibidor competitivo das óxido nítrico-sintetases, sobre o fenômeno. MATERIAL E MÉTODOS: Utilizaram-se ratos, Wistar, machos, SPF ("specific-pathogen free"), adultos, adaptados às condições do laboratório, que após 24 horas de jejum alimentar foram pré-tratados endovenosamente com veículo (salina) ou Nw-nitro-L-arginine methyl ester nas doses de 0,5, 1, 2,5 e 5 mg/kg. No tratamento, administrou-se endovenosamente veículo (salina) ou lipopolissacarídio (50 µg/kg). O intervalo entre o pré-tratamento e o tratamento foi de 10 minutos, e entre este e a avaliação do esvaziamento gástrico foi de 60 minutos. O esvaziamento gástrico foi avaliado indiretamente através da determinação da retenção gástrica da solução salina marcada com fenol vermelho 10 minutos após administração por via orogástrica. RESULTADOS: Entre os animais pré-tratados com veículo, o tratamento com lipopolissacarídio determinou elevação significativa da retenção gástrica (média = 57%) em relação aos tratados com veículo (38,1%). O pré-tratamento com as diferentes doses de Nw-nitro-L-arginine methyl ester não modificou a retenção gástrica nos animais controles do tratamento. O pré-tratamento com Nw-nitro-L-arginine methyl ester com a dose de 1 mg/kg determinou redução discreta, mas significativa, na retenção gástrica (52%) nos animais tratados com lipopolissacarídio, em relação ao observado naqueles com pré-tratamento e tratamento com veículo (35,9%). Nos animais pré-tratados com 2,5 e 5 mg/kg de Nw-nitro-L-arginine methyl ester e tratados com lipopolissacarídio, houve aumento significante da retenção gástrica (74,7% e 80,5%, respectivamente) em relação aos seus controles pré-tratados com as mesmas doses do inibidor das óxido nítrico-sintetases e tratados com veículo (40,5% e 38,7%, respectivamente) e àqueles pré-tratados com veículo e tratados com a mesma toxina. CONCLUSÃO: O pré-tratamento com Nw-nitro-L-arginine methyl ester numa dose baixa (1 mg/kg) determinou redução discreta no efeito de retardo do esvaziamento gástrico determinado pelo lipopolissacarídio in vivo e aumento significativo do retardo com doses mais elevadas (2,5 e 5 mg/kg), doses estas que, per se, não interferem no esvaziamento.

scholarly journals Microbiota Facilitates the Formation of the Aminated Metabolite of Tea Polyphenols Which Trap Deleterious Reactive Endogenous Metabolites (P06-022-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Shuwei Zhang ◽  
Yantao Zhao ◽  
Christina Ohland ◽  
Christian Jobin ◽  
Shengmin Sang
Keyword(s):  
Gut Microbiota ◽  
Chronic Diseases ◽  
Green Tea ◽  
Tea Polyphenols ◽  
Specific Pathogen Free ◽  
Tea Polyphenol ◽  
Germ Free ◽  
Specific Pathogen ◽  
Conjugated Metabolites

Abstract Objectives The in vivo mechanism of tea polyphenol-mediated prevention of many chronic diseases is still largely unknown. Studies have shown that accumulation of toxic reactive cellular metabolites, such as ammonia and reactive carbonyl species (RCS), is one of the causing factors to the development of many chronic diseases. The objective of this study is to investigated the in vivo interaction between tea polyphenols and ammonia and RCS. Methods In mice, we gave 200 mg/kg tea polyphenol ((-)-epigallocatechin-3-gallate (EGCG) or theaflavin) to CD-1 mice, 129/SvEv specific-pathogen-free (SPF) mice, or germ-free (GF) mice. Urinary and fecal samples were collected in metabolic cages for 24 h. In humans, two healthy volunteers drank 4 cups of Lipton green tea every day for four days. On the fourth day, 24 h urinary and fecal samples were collected after consuming the first cup of tea. Using LC tandem mass, we searched the formation of the aminated and RCS conjugated metabolites of tea polyphenols. Chemical standards were synthesized to confirm the structures of these metabolites. In order to study the impact of gut microbiota on the formation of these metabolites, we also quantified the concentrations of these metabolites in SPF and GF mice. Results We found that both EGCG and theaflavin could rapidly react with ammonia to generate the aminated metabolites. Both tea polyphenols and their aminated metabolites could further scavenge RCS, such as methylglyoxal (MGO), malondialdehyde (MDA), and trans-4-hydroxy-2-nonenal (4-HNE), to produce the RCS conjugates of tea polyphenols and the aminated tea polyphenols. Both the aminated and the RCS conjugated metabolites of EGCG were detected in human after drinking four cups of green tea per day. By comparing the levels of the aminated and the RCS conjugated metabolites in EGCG or theaflavin exposed germ-free (GF) mice and specific-pathogen-free (SPF) mice, we demonstrated that gut microbiota facilitate the formation of the aminated metabolites of tea polyphenols, the RCS conjugates of tea polyphenols, and the RCS conjugates of the aminated tea polyphenols. Conclusions Altogether, this study provides in vivo evidences that tea polyphenols have the capacity to scavenge toxic reactive metabolic wastes. This finding opens a new window to understand the underlying mechanisms by which drinking tea could prevent the development of chronic diseases. Funding Sources We gratefully acknowledge financial support from NIH R01 grant AT008623 to this work.

scholarly journals 179IMPORTANCE OF EMBRYO TRANSFERS IN TRANSGENIC MOUSE FACILITIES

2004 ◽  
Vol 16 (2) ◽  
pp. 211
Author(s):  
E. Mahabir ◽  
A. Mayer ◽  
S. Marschall ◽  
M. Hrabe de Angelis ◽  
J. Schmidt
Keyword(s):  
Embryo Transfer ◽  
Germ Line ◽  
Hepatitis Virus ◽  
Embryonic Stem ◽  
Specific Pathogen Free ◽  
Health Standards ◽  
Specific Pathogen ◽  
Cryopreserved Sperm ◽  
Mouse Lines

With the increasing demand for and production of transgenic and mutant mice for biomedical research, embryo transfer plays a paramount role. The purpose of performing embryo transfer in this species is to generate transgenic mice via blastocyst injection of embryonic stem cells or pronuclear injection of DNA constructs, to revitalize cryopreserved sperm and embryos, and to generate mouse lines that meet specific pathogen-free health standards for breeding in barrier areas (rederivation). We present results from two years of carrying out embryo transfers for rederivation purposes in the large mouse breeding facility of the GSF—National Research Center for Environment and Health, Neuherberg, Germany. Pathogens to be eradicated from inbred transgenic (C57BL/6 background) and mutant (C3H background) mouse lines included mouse hepatitis virus, mouse minute virus, and mouse parvovirus. In vitro- and in vivo-produced two-cell embryos were washed 3 times in M2 medium. A total of 20 embryos each were transferred to the oviduct of 8- to 12-week-old specific pathogen-free pseudopregnant (Day 0.5) Swiss recipients under aseptic conditions. Mice were then kept singly in individually ventilated cages and manipulated in a Class II laminar flow hood. From each transfer to one to five recipients with embryos originating from the same mouse line, one recipient was tested for the presence of microorganisms 6 to 12 weeks after embryo transfer, i.e. at 0 to 6 weeks after weaning, according to the FELASA (Federation of European Laboratory Animal Science Associations) Guidelines. A total of 290 embryo transfers were performed for revitalization of cryopreserved sperm from 52 mouse lines, cryopreserved two-cell embryos from 18 mouse lines and rederivation of 12 mouse lines using freshly collected two-cell embryos. From these 290 embryo transfers, 59 mouse lines were re-established (40 from cryopreserved sperm, 7 from cryopreserved embryos and 12 from in vivo-produced embryos). Health monitoring of 54 recipients showed that all mouse lines generated were free of all pathogens stated in the FELASA list. The results presented here show that all 12 (100%) mouse lines were re-established after transfer of freshly collected two-cell embryos whereas 77% and 39% success rates were observed for revitalization of cryopreserved sperm and embryos, respectively. The success of embryo transfer in eradicating pathogens depends on the inability of these pathogens to transverse the zona pellucida and enter and/or infect embryonic cells. In our mouse facility, embryo transfer provided an efficient method to successfully revitalize cells of the mouse germ line as well as to eradicate prevalent murine pathogens. Furthermore, the results demonstrate the efficiency of transferring embryos of different origins and thereby obtaining and maintaining specific pathogen-free health standards in our mouse colonies.

Characterization Of The Lung Microbiome Of Specific Pathogen-Free Mice With And Without Exposure To Cigarette Smoke In Vivo

2011 ◽  
Author(s):  
Michael C. Shen ◽  
Angela M. Preston ◽  
Merritt G. Gillilland III ◽  
John R. Erb-Downward ◽  
Bradley Todd ◽  
...  
Keyword(s):  
Cigarette Smoke ◽  
Specific Pathogen Free ◽  
Lung Microbiome ◽  
Specific Pathogen

Interference between low pathogenic avian influenza H9N2 and avirulent Newcastle diseases viruses in embryonated Specific Pathogen-Free chicken eggs

2021 ◽  
Vol 1 (2) ◽  
pp. 7-10
Author(s):  
Amal Essalah-Bennani ◽  
Asma Fagrach ◽  
Abderrazak El Khantour ◽  
Ouafaa Fassi Fihri ◽  
Moncef Bouzouaia ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Virus Replication ◽  
Model Assessment ◽  
Specific Pathogen Free ◽  
Pathogenic Avian Influenza ◽  
Specific Pathogen ◽  
Pathogenic Avian Influenza Virus ◽  
Low Pathogenic Avian Influenza

Co-infection with low pathogenic avian influenza virus (LPAIV) H9N2 and Newcastle disease virus (NDV) has become a worrying concern for the poultry industry. The problem arises when the hidden virus influences the replication of another suspected virus. Subsequently, misdiagnosis of the actual cause may be ended up as a source of contamination for the other healthy flocks by the spread of the covered-up virus. In this preliminary study, we determined the potential impact of concurrent infection with H9N2 and avirulent NDV (Lasota) on the virus replication in Specific Pathogen-Free embryonated chicken egg (SPF-ECE) model. Assessment of the potential interference phenomena was carried out based on embryonic lesions, mortalities, and virus replication using real-time PCR. Our results showed that H9N2 interferes with LaSota growth, regardless of which infection occurred first. Our obtained preliminary results are a call for scientists to study the interference between LPAIV H9N2 and NDV both in-vivo and in-vitro in more detail.

Prevention of 5-fluorouracil-induced infection with indigenous Escherichia coli in tumor-bearing mice by nonspecific immunostimulation

1992 ◽  
Vol 38 (8) ◽  
pp. 774-778 ◽  
Author(s):  
Koji Nomoto ◽  
Teruo Yokokura ◽  
Kikuo Nomoto
Keyword(s):  
Escherichia Coli ◽  
Lactobacillus Casei ◽  
Lethal Dose ◽  
Systemic Infection ◽  
Specific Pathogen Free ◽  
E Coli ◽  
Tumor Bearing ◽  
Lethal Toxicity ◽  
Specific Pathogen

We have previously reported that the lethal toxicity of 5-fluorouracil (5-FU) in specific-pathogen-free mice is due to an indigenous infection with Escherichia coli (K. Nomoto, T. Yokokura, Y. Yoshikai, et al. Can. J. Microbiol. 37: 244–247, 1991). In the present study, we demonstrate that nonspecific immunostimulation augments host resistance against the lethal toxicity of 5-FU in tumor-bearing mice. Intravenous administration of a preparation of heat-killed Lactobacillus casei (LC 9018), a nonspecific immunostimulant, at a dose of 20 mg/kg to BALB/c mice augmented their resistance against the lethal toxicity of 5-FU if the preparation was injected into the mice 10–40 days before administration of 5-FU. Injection of LC 9018 into BALB/c mice bearing Meth A fibrosarcoma also enhanced their resistance against the lethality of 5-FU. Systemic infection with E. coli was induced in all of the 5-FU-treated tumor-bearing mice 10 days or more after administration of the drug at a lethal dose of 500 mg/kg, and it was accompanied by an overgrowth of the bacteria in the intestine. Treatment of tumor-bearing mice with LC 9018 resulted in decreased rates of occurrence of systemic infection with E. coli and inhibition of overgrowth of the bacteria in the intestine after administration of 5-FU. A single administration of either LC 9018 or 5-FU significantly inhibited the growth of Meth A cells in vivo, and a combined antitumor effect was shown in the mice treated with both 5-FU and LC 9018. Key words: tumor-bearing mice, fluorouracil, nonspecific immunostimulation, indigenous infection, Escherichia coli.

scholarly journals Study of Full-Length Porcine Endogenous Retrovirus Genomes with Envelope Gene Polymorphism in a Specific-Pathogen-Free Large White Swine Herd

2000 ◽  
Vol 74 (18) ◽  
pp. 8575-8581 ◽  
Author(s):  
Steffi Bösch ◽  
Claire Arnauld ◽  
André Jestin
Keyword(s):  
Endogenous Retrovirus ◽  
Amino Acid Sequences ◽  
Full Length ◽  
Endogenous Retroviruses ◽  
Envelope Gene ◽  
Specific Pathogen Free ◽  
Large White ◽  
Porcine Endogenous Retrovirus ◽  
Specific Pathogen

ABSTRACT Specific-pathogen-free (SPF) swine appear to be the most appropriate candidate for pig to human xenotransplantation. Still, the risk of endogenous retrovirus transmission represents a major obstacle, since two human-tropic porcine endogenous retroviruses (PERVs) had been characterized in vitro (P. Le Tissier, J. P. Stoye, Y. Takeuchi, C. Patience, and R. A. Weiss, Nature 389:681–682, 1997). Here we addressed the question of PERV distribution in a French Large White SPF pig herd in vivo. First, PCR screening for previously described PERV envelope genes envA, envB, and envC(D. E. Akiyoshi, M. Denaro, H. Zhu, J. L. Greenstein, P. Banerjee, and J. A. Fishman, J. Virol. 72:4503–4507, 1998; Le Tissier et al., op. cit.). demonstrated ubiquity of envAand envB sequences, whereas envC genes were absent in some animals. On this basis, selective out-breeding of pigs of remote origin might be a means to reduce proviral load in organ donors. Second, we investigated PERV genome carriage inenvC negative swine. Eleven distinct full-length PERV transcripts were isolated. The sequence of the complete envelope open reading frame was determined. The deduced amino acid sequences revealed the existence of four clones with functional and five clones with defective PERV PK-15 A- and B-like envelope sequences. The occurrence of easily detectable levels of PERV variants in different pig tissues in vivo heightens the need to assess PERV transmission in xenotransplantation animal models.

Hyperoxia inhibits stimulated superoxide release by rat alveolar macrophages

1982 ◽  
Vol 53 (3) ◽  
pp. 685-689 ◽  
Author(s):  
H. J. Forman ◽  
J. J. Williams ◽  
J. Nelson ◽  
R. P. Daniele ◽  
A. B. Fisher
Keyword(s):  
Alveolar Macrophages ◽  
Polymorphonuclear Leukocytes ◽  
Cell Types ◽  
Lavage Fluid ◽  
Significant Decline ◽  
Specific Pathogen Free ◽  
Specific Pathogen ◽  
Cytochrome C Reduction

Factors responsible for the loss of respiratory burst capacity (stimulated extracellular O2-. release) of alveolar macrophages (AM) exposed to prolonged hyperoxia were assessed. Specific pathogen-free rats were exposed to 1 ATA O2 for 24–72 h, and lungs of survivors lavaged. Release of O2-. by cells after addition of concanavalin A, which stimulated AM but not polymorphonuclear leukocytes (PMN), or digitonin, which stimulated both cell types, was measured using cytochrome c reduction +/- superoxide dismutase. O2-. release by AM declined 47.2% (P less than 0.05) after 24 h of hyperoxia and 100% after 60 h. Percent PMN in the lavage was less than 3% at 0–36 h but increased to 16% at 48 h and to 44% at 72 h. Although addition of PMN to AM in vitro caused inhibition of AM O2-. release, the percent PMN required for inhibition was not reached in vivo until after a significant decline in AM O2-.-releasing capacity had already occurred. Cell-free lavage fluid from either control or hyperoxic rats did not affect AM O2-. release. AM in culture for 24 h in hyperoxia lost 76.7% (P less than 0.005) of O2-.-releasing capacity vs. cells incubated in 20% O2, although dye exclusion was unaffected. The results indicate that the major cause of loss of AM O2-. release by hyperoxia is a direct effect of O2 on the cells.

scholarly journals Host-specific differences in the contribution of an ESBL IncI1 plasmid to intestinal colonization by Escherichia coli O104:H4

2018 ◽  
Vol 73 (6) ◽  
pp. 1579-1585 ◽  
Author(s):  
M Giles ◽  
S A Cawthraw ◽  
M AbuOun ◽  
C M Thomas ◽  
D Munera ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Animal Species ◽  
Host Bacterium ◽  
Intestinal Colonization ◽  
Specific Pathogen Free ◽  
E Coli ◽  
New Zealand White Rabbits ◽  
Specific Pathogen ◽  
Transmission Reservoir

AbstractObjectivesTo assess stability and contribution of a large ESBL-encoding IncI1 plasmid to intestinal colonization by Escherichia coli O104:H4 in two different mammalian hosts.MethodsSpecific-pathogen-free 3–4-day-old New Zealand White rabbits and conventionally reared 6-week-old weaned lambs were orally infected with WT E. coli O104:H4 or the ESBL-plasmid-cured derivative, and the recovery of bacteria in intestinal homogenates and faeces monitored over time.ResultsCarriage of the ESBL plasmid had differing impacts on E. coli O104:H4 colonization of the two experimental hosts. The plasmid-cured strain was recovered at significantly higher levels than WT during late-stage colonization of rabbits, but at lower levels than WT in sheep. Regardless of the animal host, the ESBL plasmid was stably maintained in virtually all in vivo passaged bacteria that were examined.ConclusionsThese findings suggest that carriage of ESBL plasmids has distinct effects on the host bacterium depending upon the animal species it encounters and demonstrates that, as for E. coli O157:H7, ruminants could represent a potential transmission reservoir.

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