RESUMO
AIM: Examine a clinical laundry facility for the presence of methicillin-resistant Staphylococcus aureus (MRSA) on environmental surfaces and among personnel. METHODS: Nasal and face samples along with surface samples were collected four times in 2015. MRSA isolates were confirmed using standardized biochemical assays and molecular characterization. RESULTS: MRSA was identified in 33/120 (28%) samples from the dirty and 3/120 (3%) samples from the clean environmental areas. MRSA isolates included: (dirty) ST5 SCCmec type II, ST8 SCCmec type IV, ST231 SCCmec type II, ST239 SCCmec type III, ST239 SCCmec type IV, ST256 SCCmec type IV and (clean) ST5 SCCmec type II and ST8 SCCmec type IV. Five different employees were MRSA positive, 4/8 (50%) from the dirty: and 1/15 (6·7%) from the clean, but there was a 10-fold higher MRSA carriage 6/22 (27%) dirty vs 1/38 (2·6%) clean when all 50 human samples were combined. CONCLUSION: MRSA prevalence was significantly higher (28 vs 3%) in dirty vs clean areas within the laundry facility suggesting a greater risk for personnel on the dirty side. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report of isolation and characterization of MRSA from surfaces and personnel from a clinical laundry facility.
Assuntos
Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Infecções Estafilocócicas/microbiologia , Antibacterianos/farmacologia , Contaminação de Equipamentos , Pessoal de Saúde , Humanos , Meticilina/farmacologia , Staphylococcus aureus Resistente à Meticilina/classificação , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/genética , Testes de Sensibilidade Microbiana , Infecções Estafilocócicas/transmissãoRESUMO
Polyomaviruses produce latent and asymptomatic infections in many species, but productive and lytic infections are rare. In immunocompromised humans, polyomaviruses can cause tubulointerstitial nephritis, demyelination, or meningoencephalitis in the central nervous system and interstitial pneumonia. This report describes 2 Standardbred horses with tubular necrosis and tubulointerstitial nephritis associated with productive equine polyomavirus infection that resembles BK polyomavirus nephropathy in immunocompromised humans.
Assuntos
Doenças dos Cavalos/patologia , Doenças dos Cavalos/virologia , Hospedeiro Imunocomprometido/imunologia , Necrose do Córtex Renal/veterinária , Nefrite Intersticial/veterinária , Infecções por Polyomavirus/veterinária , Polyomavirus/genética , Animais , Análise Química do Sangue/veterinária , Proteínas do Capsídeo/genética , Primers do DNA/genética , Evolução Fatal , Feminino , Doenças dos Cavalos/imunologia , Cavalos , Imunoglobulina G/sangue , Imuno-Histoquímica/veterinária , Necrose do Córtex Renal/patologia , Necrose do Córtex Renal/virologia , Masculino , Nefrite Intersticial/patologia , Nefrite Intersticial/virologia , Filogenia , Infecções por Polyomavirus/patologiaRESUMO
AIM: Isolation and characterization of methicillin-resistant Staphylococcus aureus (MRSA) from frequently touched nonhospital environmental surfaces at a large university, student homes and community sites. METHODS AND RESULTS: Twenty-four isolates from 21 (4·1%, n = 509) surfaces were MRSA positive and included 14 (58%, n = 24) SCCmec type IV, two (8%, n = 24) type I, and eight (33%, n = 24) were not type I-IV (NT). Six different multilocus sequencing types were identified by PCR and sequencing. PCR assays identified one (4·2%, n = 24) Panton-Valentine leukocidin (PVL) positive, 22 (92%, n = 24) arginine catabolic mobile element (ACME) positive and 23 (96%, n = 24) multidrug-resistant (kanamycin, macrolide, tetracycline) MRSA isolates. Eleven (46%, n = 24) USA300 isolates were determined by pulsed-field gel electrophoresis. CONCLUSION: The MRSA-positive environmental surfaces were identified in student homes (11·8%, n = 85), the community (2·3%, n = 130) and the university (2·7%, n = 294). USA300 strains were isolated from the university, student homes and community samples. This is the first report of the animal clone ST97 on urban environmental surfaces. SIGNIFICANCE AND IMPACT OF THE STUDY: The study highlights the distribution of USA300 on frequently touched surfaces. Whether contact with these MRSA contaminated environmental surfaces are associated with increased risk of transmission of MRSA to people needs further research.
Assuntos
Microbiologia Ambiental , Fômites/microbiologia , Habitação , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Universidades , Técnicas de Tipagem Bacteriana , Eletroforese em Gel de Campo Pulsado , Staphylococcus aureus Resistente à Meticilina/classificação , Tipagem de Sequências Multilocus , Reação em Cadeia da PolimeraseRESUMO
The dairy industry in the United States is amidst a long-running trend toward fewer, larger dairy farms. This development has created a backlash in some communities over concerns such as odor, waste management, and environmental degradation. Separately, anaerobic digestion has advanced as a waste management technology that potentially offers solutions to some of these issues, providing odor control and a combustible biogas among other things. These digesters require significant capital investments. Voluntary consumer premiums for the renewable energy produced have been used in some instances as a means to move adoption of such systems toward financial feasibility. This project employed a survey to measure Ohio consumers' willingness to pay a premium for renewable energy produced by anaerobic digesters on dairy farms. Cluster analysis was used to segment consumers by willingness to pay, age, education, income, self-identified political inclination, and a composite variable that served as a proxy for respondents' environmental stewardship. Four distinctive groups emerged from the data. Older, less educated respondents were found to have the least amount of support for digesters on dairy farms, whereas politically liberal, environmentally proactive respondents demonstrated the strongest support. Well-educated, affluent respondents and young respondents fell between these 2 groups. Most large dairy farms are generally met with fairly negative responses from their local communities; in contrast, this research finds some popular support for anaerobic digestion technology. Going forward, establishing a positive link between support for anaerobic digesters and for their use on large dairies could open up a new route for less-contested large dairy farm developments. Evaluation of community demographics could become an important part of finding an optimal location for a large dairy farm.
Assuntos
Comportamento do Consumidor/estatística & dados numéricos , Indústria de Laticínios/métodos , Demografia/estatística & dados numéricos , Gerenciamento de Resíduos/economia , Gerenciamento de Resíduos/métodos , Adulto , Idoso , Anaerobiose , Biocombustíveis/economia , Análise por Conglomerados , Indústria de Laticínios/economia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Odorantes/prevenção & controle , Ohio , Política , Fatores Socioeconômicos , Estados UnidosRESUMO
AIMS: To determine if environmental Clostridium perfringens carry antibiotic resistance genes and if the genes are mobile. METHODS AND RESULTS: Clostridium perfringens from water, soil and sewage (2003-2006) were screened for the tetracycline and macrolide resistance genes previously described in animal and human C. perfringens [erm(B), erm(Q), tetA(P), tetB(P) and tet(M) genes] and the macrolide resistance mef(A) gene. Of the 160 isolates, 108 (67.5%) carried > or =1 of the six antibiotic resistance gene(s). The tetA(P), tetB(P) and tet(M) genes were in 53%, 22% and 8%, and the erm(B), erm(Q) and mef(A) genes in 26%, 1% and 18% of the isolates, respectively. The mef(A) gene and flanking regions were sequenced. The tet(M), erm(B), erm(Q) and mef(A) genes transfer independently from C. perfringens donors to the Enterococcus faecalis recipient. CONCLUSIONS: Six resistance genes were found in the environmental C. perfringens with the most common being the tetA(P) gene and the erm(Q) gene the least common. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first time conjugal transfer of macrolide resistance genes and/or the tet(M) gene from C. perfringens has been demonstrated. The data presented supports the hypothesis that antibiotic-resistant environmental C. perfringens are capable of acting as reservoirs for these antibiotic resistance genes.
Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Clostridium perfringens/genética , Farmacorresistência Bacteriana Múltipla/genética , Genes Bacterianos/genética , Macrolídeos/farmacologia , Resistência a Tetraciclina/genética , Tetraciclina/farmacologia , Southern Blotting , Clostridium perfringens/efeitos dos fármacos , Conjugação Genética/efeitos dos fármacos , DNA Bacteriano/genética , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Reação em Cadeia da PolimeraseRESUMO
AIMS: The tet(X) gene has previously been found in obligate anaerobic Bacteroides spp., which is curious because tet(X) encodes for a NADP-dependent monooxygenase that requires oxygen to degrade tetracycline. In this study, we characterized a tetracycline resistant, aerobic, Gram-negative Sphingobacterium sp. strain PM2-P1-29 that harbours a tet(X) gene. METHODS AND RESULTS: Sphingobacterium sp. PM2-P1-29 demonstrated the ability to transform tetracycline compared with killed controls. The presence of the tet(X) gene was verified by PCR and nucleotide sequence analysis. Additional nucleotide sequence analysis of regions flanking the tet(X) gene revealed a mobilizable transposon-like element (Tn6031) that shared organizational features and genes with the previously described Bacteroides conjugative transposon CTnDOT. A circular transposition intermediate of the tet(X) region, characteristic of mobilizable transposons, was detected. However, we could not demonstrate the conjugal transfer of the tet(X) gene using three different recipient strains and numerous experimental conditions. CONCLUSIONS: This study suggests that Sphingobacterium sp. PM2-P1-29 or a related bacterium may be an ancestral source of the tet(X) gene. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrates the importance of environmental bacteria and lateral gene transfer in the dissemination and proliferation of antibiotic resistance among bacteria.
Assuntos
Conjugação Genética , Sphingobacterium/genética , Resistência a Tetraciclina/genética , Sequência de Bases , DNA Bacteriano/genética , Testes de Sensibilidade Microbiana , Reação em Cadeia da Polimerase , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Sphingobacterium/metabolismo , Tetraciclina/metabolismo , Tetraciclina/farmacologiaRESUMO
AIMS: The aim of the study was to determine if vancomycin-resistant Enterococcus spp. [VRE] carrying vanA and/or vanB genes were present in public marine beaches and a fishing pier [2001-2003, 2008] from Washington and California [2008]. METHODS: PCR assays for the vanA and/or vanB genes with verification by DNA-DNA hybridization of the PCR products were used. Positive isolates were speciated using the BD BBL Crystal Identification and/or by sequencing the 16S ribosomal region. RESULTS: Eighteen (8%) of 227 isolates including Enterococcus faecalis, Enterococcus faecium, Enterococcus casseliflavus/gallinarum and a Staphylococcus epidermidis carrying vanA and/or vanB genes, from four of six Washington and one of two California sites, were identified. Selected VRE and the S. epidermidis were able to transfer their van genes to an E. faecalis recipient at frequencies ranging from 1.9 x 10(-6) to 6.7 x 10(-9). CONCLUSIONS: Vancomycin-resistant Enterococcus spp. was isolated from five of the seven sites suggesting that other North America public beaches could be the reservoirs for VRE and should be assessed. SIGNIFICANCE & IMPACT OF THE STUDY: This is the first report of isolation and characterization of VRE strains (and a vanB Staphylococcus sp.) from North American environmental sources suggesting that public beaches may be a reservoir for possible transmission of VRE to beach visitors.
Assuntos
Enterococcus/genética , Enterococcus/isolamento & purificação , Sedimentos Geológicos/microbiologia , Água do Mar/microbiologia , Resistência a Vancomicina/genética , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , California , Conjugação Genética/efeitos dos fármacos , DNA Bacteriano/genética , Eletroforese em Gel de Poliacrilamida , Enterococcus/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Reação em Cadeia da Polimerase/métodos , RNA Ribossômico 16S/genética , Dióxido de Silício , Staphylococcus/efeitos dos fármacos , Staphylococcus/genética , Staphylococcus/isolamento & purificação , Estreptomicina/farmacologia , Vancomicina/farmacologia , Resistência a Vancomicina/efeitos dos fármacos , WashingtonRESUMO
Mercury emitted from dental amalgam may select for increased numbers of antibiotic- or mercury-resistant commensal bacteria in patients and increase their risk for bacterial diseases that are resistant to common therapies. We hypothesized that the presence of dental amalgams would increase the level of mercury-, tetracycline-, ampicillin-, erythromycin-, or chloramphenicol-resistant oral and urinary bacteria as compared with levels in children receiving composite fillings. Samples were collected at baseline, 3-6 months after the initial dental treatment, and annually for 7 years of follow-up. There were no statistically significant differences between treatment groups in the numbers of bacteria growing on antibiotic- or mercury-supplemented plates. This study provided no evidence that amalgam fillings on posterior teeth influenced the level of antibiotic- or mercury-resistant oral or urinary bacteria as detected by culture.
Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Amálgama Dentário/farmacologia , Cárie Dentária/microbiologia , Resistência Microbiana a Medicamentos , Adolescente , Antibacterianos/metabolismo , Criança , Amálgama Dentário/metabolismo , Cárie Dentária/terapia , Restauração Dentária Permanente/métodos , Feminino , Humanos , Estudos Longitudinais , Masculino , Boca/microbiologiaRESUMO
Prostaglandins (PG) are cytoprotective for gastrointestinal epithelium, possibly because they enhance mucosal repair. The objective of the present studies was to assess the role of prostaglandins in intestinal repair. Intestinal mucosa from porcine ileum subjected to 1 h of ischemia was mounted in Ussing chambers. Recovery of normal transepithelial electrical resistance occurred within 2 h, and continued to increase for a further 2 h to a value twice that of control. The latter response was blocked by inhibition of prostaglandin synthesis, and restored by addition of both carbacyclin (an analog of PGI2) and PGE2, whereas the addition of each alone had little effect. Histologically, prostaglandins had no effect on epithelial restitution or villous contraction, indicating that elevations in transepithelial resistance were associated with increases in paracellular resistance. Furthermore, prostaglandin-stimulated elevations in resistance were inhibited with cytochalasin D, an agent known to stimulate cytoskeletal contraction. Synergistic elevations in transepithelial resistance, similar to those of carbacyclin and PGE2, were also noted after treatment with cAMP and A23187 (a calcium ionophore). We conclude that PGE2 and PGI2 have a synergistic role in restoration of intestinal barrier function by increasing intracellular cAMP and Ca2+, respectively, which in turn signal cytoskeletal-mediated tight junction closure.
Assuntos
Citoproteção , Dinoprostona/farmacologia , Epoprostenol/análogos & derivados , Íleo/efeitos dos fármacos , Mucosa Intestinal/efeitos dos fármacos , Animais , Sinergismo Farmacológico , Impedância Elétrica , Epitélio/efeitos dos fármacos , Epitélio/metabolismo , Epoprostenol/farmacologia , Feminino , Íleo/metabolismo , Técnicas In Vitro , Indometacina/farmacologia , Mucosa Intestinal/metabolismo , Inulina/metabolismo , Masculino , Permeabilidade/efeitos dos fármacos , Traumatismo por Reperfusão/tratamento farmacológico , SuínosRESUMO
Growth factor-independent 32D-src and 32D-abl cell lines, established by infecting the interleukin-3-dependent myeloid precursor cell line (32D-123) with retroviruses containing the src or abl oncogene, were used to study transcriptional regulation of transforming growth factor beta 1 (TGF-beta 1) mRNA. Analysis of different TGF-beta 1 promoter constructs regulated by pp60v-src indicated that sequences responsive to high levels of src induction contain binding sites for AP-1. Both src and serum induced expression of the c-fos and c-jun genes in myeloid cells, resulting in transcriptional activation of the TGF-beta 1 gene. We found that serum treatment increased TGF-beta 1 mRNA levels in 32D-123 cells and that the v-Src protein could replace the serum requirement by stimulating binding to the AP-1 complex of the TGF-beta 1 promoter, thereby mediating the induction of TGF-beta 1 transcription.
Assuntos
Proteínas de Ligação a DNA/metabolismo , Regulação da Expressão Gênica , Proteína Oncogênica pp60(v-src)/metabolismo , Regiões Promotoras Genéticas , Proteínas Tirosina Quinases/metabolismo , Fatores de Transcrição/metabolismo , Transcrição Gênica , Fatores de Crescimento Transformadores/genética , Animais , Sequência de Bases , Linhagem Celular , Proteínas de Ligação a DNA/genética , Camundongos , Dados de Sequência Molecular , Sondas de Oligonucleotídeos , Plasmídeos , Proteínas Proto-Oncogênicas c-jun , Fatores de Transcrição/genéticaRESUMO
Deregulated expression of v-abl and BCR/abl genes has been associated with myeloproliferative syndromes and myelodysplasia, both of which can progress to acute leukemia. These studies identify the localization of the oncogenic form of the abl gene product encoded by the Abelson murine leukemia virus in the nuclei of myeloid cells and the association of the v-Abl protein with the transcriptional regulator cyclic AMP response element-binding protein (CREB). We have mapped the specific domains within each of the proteins responsible for this interaction. We have shown that complex formation is a prerequisite for transcriptional potentiation of CREB. Transient overexpression of the homologous cellular protein c-Abl also results in the activation of promoters containing an intact CRE. These observations identify a novel function for v-Abl, that of a transcriptional activator that physically interacts with a transcription factor.
Assuntos
Núcleo Celular/metabolismo , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Proteínas Oncogênicas v-abl/metabolismo , Proteínas de Saccharomyces cerevisiae , Fatores de Transcrição , Ativação Transcricional , Sequência de Bases , Sítios de Ligação , Compartimento Celular , Transformação Celular Viral , Células Cultivadas , Citoplasma/metabolismo , Proteínas de Ligação a DNA , Proteínas Fúngicas/metabolismo , Humanos , Dados de Sequência Molecular , Oligodesoxirribonucleotídeos/química , Ligação ProteicaRESUMO
BACKGROUND: Enterococcus spp. are a normal part of the gastrointestinal tract of humans and animals. They are also important pathogens, being responsible for 14% of US nosocomial infections from 2007 to 2010. AIM: To examine a laundry facility that processes clinical linens for the presence and seasonality of vancomycin-resistant Enterococcus spp. METHODS: Surface samples were collected four times in 2015 from the dirty and clean areas of the laundry facility. Isolates were confirmed using biochemical assays, and antibiotic susceptibility testing was performed. Further investigations included molecular characterization by multi-locus sequence typing (MLST), detection of acquired vanA and vanB and/or intrinsic vanC1 genes by polymerase chain reaction, and eBURST analysis. FINDINGS: Seventy-four vanA-positive multi-drug-resistant Enterococcus spp. were identified: 64/120 (53%) in the dirty area and 10/120 (8%) in the clean area. There were 14 ST types among the E. faecium isolates identified (ST16, 17, 18, 117, 186, 280, 324, 412, 584, 664, 665, 736, 750 and 1038). Both E. faecalis isolates were ST109. CONCLUSION: Isolation of vancomycin-resistant enterococci (VRE) isolates was significantly higher (53% vs 8%) in the dirty area of the facility compared with the clean area. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study to examine an industrial laundry facility for the presence of VRE, and may be an unrecognized reservoir.
Assuntos
Proteínas de Bactérias/genética , Carbono-Oxigênio Ligases/genética , Farmacorresistência Bacteriana Múltipla , Enterococcus faecalis/isolamento & purificação , Enterococcus faecium/isolamento & purificação , Microbiologia Ambiental , Serviço Hospitalar de Lavanderia , Enterococos Resistentes à Vancomicina/isolamento & purificação , Técnicas Bacteriológicas , Enterococcus faecalis/classificação , Enterococcus faecalis/efeitos dos fármacos , Enterococcus faecalis/genética , Enterococcus faecium/classificação , Enterococcus faecium/efeitos dos fármacos , Enterococcus faecium/genética , Hospitais , Humanos , Tipagem de Sequências Multilocus , Peptídeo Sintases/genética , Reação em Cadeia da Polimerase , Prevalência , Estados Unidos , Enterococos Resistentes à Vancomicina/classificação , Enterococos Resistentes à Vancomicina/efeitos dos fármacos , Enterococos Resistentes à Vancomicina/genéticaRESUMO
This study examined the relationship of prenatal transportation stress (PNS) with exogenous GnRH-induced LH and testosterone secretion in sexually mature Brahman bulls. Brahman cows (n = 96; 48 were stressed by transportation at 5 stages of gestation and 48 were controls) produced a calf crop of 85 calves. All bulls (n = 46) from this calf crop were electroejaculated every 2 wk beginning at a scrotal circumference of 24 cm until sexual maturity (SM; i.e., 500 million sperm/ejaculate). The initial 11 control and 12 PNS bulls to reach SM were selected for the experiment. Within 7-21 d after reaching SM, bulls were fitted with jugular cannulas, from which blood samples were collected at 15-min intervals for 6 h prior to exogenous GnRH administration (10 ng/kg BW; i.v.) and for 6 h after GnRH. Serum concentrations of LH, testosterone, and cortisol were determined by RIA. Age and body weight did not differ ( > 0.1) between PNS and control bulls at the time of the experiment. All bulls responded similarly to exogenous GnRH, indicating no influence of PNS on LH or testosterone response to GnRH. More ( < 0.01) PNS (9 of 11) than control (3 of 12) bulls exhibited an endogenous pre-GnRH LH pulse, and more ( = 0.02) PNS (9 of 11) than control bulls (4 of 12) exhibited a pre-GnRH testosterone response to LH. The average concentration of testosterone during the 60 min (time -60, -45, -30, -15, and 0 min relative to GnRH) immediately preceding GnRH, tended to be greater ( = 0.07) in PNS (1.46 ± 0.30 ng/mL) than control (0.68 ± 0.28 ng/mL) bulls. During that time span serum cortisol was lower ( < 0.01) in PNS (4.00 ± 0.91 ng/mL) than control (7.8 ± 0.87 ng/mL) bulls. A treatment by time interaction ( = 0.03) affected testosterone concentrations from time -240 to 360 min relative to GnRH. Results from this study indicate that PNS did not affect pituitary responsiveness to GnRH or testicular responsiveness to GnRH-induced LH secretion.
Assuntos
Bovinos/fisiologia , Hormônio Liberador de Gonadotropina/farmacologia , Hormônio Luteinizante/metabolismo , Testosterona/sangue , Meios de Transporte , Animais , Peso Corporal , Feminino , Hidrocortisona , Masculino , Hipófise/efeitos dos fármacos , Gravidez , Efeitos Tardios da Exposição Pré-Natal , Estresse Fisiológico , Testículo/efeitos dos fármacos , Testosterona/metabolismoRESUMO
Xylitol is promoted in caries-preventive strategies, yet its effective dose range is unclear. This study determined the dose-response of mutans streptococci in plaque and unstimulated saliva to xylitol gum. Participants (n = 132) were randomized: controls (G1) (sorbitol/maltitol), or combinations giving xylitol 3.44 g/day (G2), 6.88 g/day (G3), or 10.32 g/day (G4). Groups chewed 3 pellets/4 times/d. Samples were taken at baseline, 5 wks, and 6 mos, and were cultured on modified Mitis Salivarius agar for mutans streptococci and on blood agar for total culturable flora. At 5 wks, mutans streptococci levels in plaque were 10x lower than baseline in G3 and G4 (P = 0.007/0.003). There were no differences in saliva. At 6 mos, mutans streptococci in plaque for G3 and G4 remained 10x lower than baseline (P = 0.007/0.04). Saliva for G3 and G4 was lower than baseline by 8 to 9x (P = 0.011/0.038). Xylitol at 6.44 g/day and 10.32 g/day reduces mutans streptococci in plaque at 5 wks, and in plaque and unstimulated saliva at 6 mos. A plateau effect is suggested between 6.44 g and 10.32 g xylitol/day.
Assuntos
Goma de Mascar , Streptococcus mutans/efeitos dos fármacos , Edulcorantes/administração & dosagem , Xilitol/administração & dosagem , Adolescente , Adulto , Idoso , Análise de Variância , Contagem de Colônia Microbiana , Placa Dentária/microbiologia , Relação Dose-Resposta a Droga , Método Duplo-Cego , Feminino , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Saliva/microbiologiaRESUMO
Vitamin E succinate (VES), a derivative of the fat-soluble vitamin D-alpha-tocopherol (vitamin E), inhibited growth and induced apoptotic cell death of estrogen receptor-negative human breast cancer cells. VES-induced apoptosis in MDA-MB-231 and SKBR-3 cells occurred through a Fas pathway. Total protein levels of the Fas receptor (Fas; APO-1/CD-95) and the Fas ligand (Fas-L) were increased following VES treatment. In addition, VES increased cell surface Fas expression. Fas-neutralizing antibodies and Fas-L antisense oligonucleotides blocked VES-induced apoptosis. The presence of Fas-L antisense oligonucleotides also completely blocked the VES-mediated increase in Fas-L protein expression. These data indicate a role for Fas signaling in VES-mediated apoptotic cell death of human breast cancer cells. These findings also suggest that VES may be of clinical use in the treatment of aggressive human breast cancers, particularly those that are refractory to antiestrogen therapy.
Assuntos
Apoptose/efeitos dos fármacos , Neoplasias da Mama/patologia , Glicoproteínas de Membrana/fisiologia , Vitamina E/análogos & derivados , Membrana Celular/metabolismo , Proteína Ligante Fas , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Inibidores do Crescimento/farmacologia , Humanos , Glicoproteínas de Membrana/antagonistas & inibidores , Glicoproteínas de Membrana/genética , Oligonucleotídeos Antissenso , RNA Mensageiro/genética , RNA Neoplásico/genética , Receptores de Estrogênio/análise , Transdução de Sinais , Tocoferóis , Células Tumorais Cultivadas , Vitamina E/farmacologiaRESUMO
Vitamin E succinate (VES) inhibited the proliferation of the estrogen receptor-negative human breast cancer cell line, BT-20, in the G1 phase of the cell cycle. The E2F proteins are integral transcriptional components in the regulation of cell growth. Overexpression of E2F-1 blocked the ability of VES to inhibit BT-20 cell growth, suggesting that VES regulation of E2F-1 activity leads to growth arrest of BT-20 cells. VES, although having little effect on E2F-1 steady-state protein levels, decreased E2F-1 phosphorylation and transactivation activity and increased cyclin A binding to E2F-1. GAL4-E2F-1 deletion mutant studies indicated that cyclin A negatively regulates E2F function. In VES-treated BT-20 cells, the cyclin A protein exhibited reduced kinase activity, which correlated with decreased steady-state levels and binding of cyclin-dependent kinase-2 to cyclin A and increased steady-state levels and binding of p21cip1 to cyclin A and cyclin-dependent kinase-2. The functional consequence of the negative regulatory effect of VES on E2F-1 function was shown by the ability of VES to inhibit the transcriptional activation of an E2F-1 responsive gene, c-myc. These studies show that VES induces growth inhibition of BT-20 cells through a mechanism that involves cyclin A-negative regulation of E2F-mediated transcription.
Assuntos
Neoplasias da Mama/prevenção & controle , Proteínas de Transporte , Proteínas de Ciclo Celular , Ciclinas/metabolismo , Proteínas de Ligação a DNA , Fatores de Transcrição/metabolismo , Vitamina E/análogos & derivados , Western Blotting , Neoplasias da Mama/patologia , Divisão Celular/efeitos dos fármacos , Fatores de Transcrição E2F , Fator de Transcrição E2F1 , Feminino , Humanos , Proteínas Proto-Oncogênicas c-myc/metabolismo , RNA Mensageiro/metabolismo , Proteína 1 de Ligação ao Retinoblastoma , Tocoferóis , Fator de Transcrição DP1 , Ativação Transcricional/efeitos dos fármacos , Transfecção , Células Tumorais Cultivadas , Vitamina E/farmacologiaRESUMO
Tetracycline-resistant bacteria were first isolated in 1953 from Shigella dysenteriae, a bacterium which causes bacterial dysentery. Since then tetracycline-resistant bacterial have been found in increasing numbers of species and genera. This has resulted in reduced effectiveness of tetracycline therapy over time. Tetracycline resistance is normally due to the acquisition of new genes often associated with either a mobile plasmid or a transposon. These tetracycline resistance determinants are distinguishable both genetically and biochemically. Resistance is primarily due to either energy-dependent efflux of tetracycline or protection of the ribosomes from the action of tetracycline. Gram-negative tetracycline efflux proteins are linked to repressor proteins which in the absence of tetracycline block transcription of the repressor and structural efflux genes. In contrast, expression of the Gram-positive tetracycline efflux genes and some of the ribosomal protection genes appears to be regulated by attenuation of mRNA transcription. Specific tetracycline resistance genes have been identified in 32 Gram-negative and 22 Gram-positive genera. Tetracycline-resistant bacteria are found in pathogens, opportunistic and normal flora species. Tetracycline-resistant bacteria can be isolated from man, animals, food, and the environment. The nonpathogens in each of these ecosystems may play an important role as reservoirs for the antibiotic resistance genes. It is clear that if we are to reverse the trend toward increasingly antibiotic-resistant pathogenic bacteria we will need to change how antibiotics are used in both human and animal health and food production.
Assuntos
Bactérias/efeitos dos fármacos , Bactérias/genética , Genes Bacterianos , Resistência a Tetraciclina/genética , Animais , Bactérias/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Transporte/metabolismo , Regulação Bacteriana da Expressão Gênica , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/genética , Bactérias Gram-Negativas/metabolismo , Bactérias Gram-Positivas/efeitos dos fármacos , Bactérias Gram-Positivas/genética , Bactérias Gram-Positivas/metabolismo , Humanos , Dados de Sequência Molecular , Ribossomos/efeitos dos fármacos , Ribossomos/metabolismo , Tetraciclina/farmacocinética , Tetraciclina/farmacologia , Resistência a Tetraciclina/fisiologiaRESUMO
Oncogenes carried by retroviruses can alter the growth properties of many cell types. We examined the molecular mechanism by which a retrovirus containing one or a combination of oncogenes can transform and immortalize hematopoietic cells. Murine fetal liver cells were used as an enriched source of early hematopoietic cell progenitors; the cells were infected with a series of recombinant murine retroviruses capable of expressing the avian v-myc, v-H-ras and v-raf oncogenes. Three factor-independent cell lines were obtained: FL-ras/myc, FL-J2 (v-raf/v-myc) and FL-myc, a unique cell line generated using a single oncogene. Cytochemical, morphologic and phenotypic analyses indicated that these cell lines were of the monocyte lineage. Southern and Northern blot analyses revealed that the three cell lines had integrated viral DNA and were expressing the mRNA transcripts corresponding to these viral oncogenes. To examine the mechanism of factor independence, supernatants from these cell lines were tested for CSF-1 activity. Supernatants from FL-myc and FL-ras/myc cells were shown to contain CSF-1 activity and Northern blot analysis of the three cell lines revealed the presence of mRNA transcripts for the CSF-1 and c-fms genes. It is possible that the growth factor independence of these cell lines is related to the development of autocrine-induced proliferation.
Assuntos
Transformação Celular Neoplásica , Transformação Celular Viral , Genes Virais , Oncogenes , Retroviridae/genética , Animais , Linhagem Celular , Fatores Estimuladores de Colônias/biossíntese , Células-Tronco Hematopoéticas/microbiologia , Immunoblotting , Fígado/citologia , Camundongos , Fenótipo , RNA Viral/biossíntese , Transcrição GênicaRESUMO
Transformation of interleukin-3 dependent (IL-3) 32D-123 myeloid cells by p120-v-Abl produced the factor-independent 32D-abl cell line. In 32D-abl cells, myc expression was found to be significantly higher than in the parental cells and was correlated with increased E2F-1 protein expression and DNA binding ability. Surprisingly, in 32D-abl cells, TGF-beta1, a potent G1/S inhibitor of 32D-123 and 32D-abl cell growth, increased E2F transactivation as shown by increased c-myc promoter-CAT and GAL4-E2F-1 activity. In addition, TGF-beta1 was also found to increase E2F-1 protein levels but had no effect on steady-state retinoblastoma (RB) protein levels or phosphorylation state. In the absence of TGF-beta1, transient expression of RB in v-Abl expressing cells resulted in decreased c-myc transcription, inhibition of GAL4-E2F-1 driven transactivation and inhibition of cellular proliferation. RB and v-Abl were found to physically associate in vivo and in vitro via v-Abl's ATP binding region. In summary, these studies established that in myeloid cells: (1) v-Abl binds RB resulting in increased E2F-1-driven c-myc transcription, and (2) an alternative pathway exists for TGF-beta1-mediated growth inhibition of v-Abl-transformed cells, in which increased rather than decreased E2F-mediated c-myc transcription is observed.