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1.
Stem Cells Transl Med ; 8(2): 138-147, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30620122

RESUMO

Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental disorder characterized by social communication deficits and the presence of restricted interests and repetitive behaviors. We have previously reported significant improvements in behavior, including increased social functioning, improved communication abilities, and decreased clinical symptoms in children with ASD, following treatment with a single infusion of autologous cord blood in a phase I open-label trial. In the current study, we aimed to understand whether these improvements were associated with concurrent changes in brain structural connectivity. Twenty-five 2- to 6-year-old children with ASD participated in this trial. Clinical outcome measures included the Vineland Adaptive Behavior Scales-II Socialization Subscale, Expressive One-Word Picture Vocabulary Test-4, and the Clinical Global Impression-Improvement Scale. Structural connectivity was measured at baseline and at 6 months in a subset of 19 children with 25-direction diffusion tensor imaging and deterministic tractography. Behavioral improvements were associated with increased white matter connectivity in frontal, temporal, and subcortical regions (hippocampus and basal ganglia) that have been previously shown to show anatomical, connectivity, and functional abnormalities in ASD. The current results suggest that improvements in social communication skills and a reduction in symptoms in children with ASD following treatment with autologous cord blood infusion were associated with increased structural connectivity in brain networks supporting social, communication, and language abilities. Stem Cells Translational Medicine 2019;8:138&10.


Assuntos
Transtorno do Espectro Autista/fisiopatologia , Transtorno do Espectro Autista/terapia , Transtorno Autístico/fisiopatologia , Transtorno Autístico/terapia , Sangue Fetal/fisiologia , Substância Branca/fisiopatologia , Gânglios da Base/fisiopatologia , Criança , Pré-Escolar , Comunicação , Feminino , Hipocampo/fisiopatologia , Humanos , Masculino , Habilidades Sociais
2.
Depress Anxiety ; 35(11): 1018-1029, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30256497

RESUMO

BACKGROUND: Smaller hippocampal volume in patients with posttraumatic stress disorder (PTSD) represents the most consistently reported structural alteration in the brain. Subfields of the hippocampus play distinct roles in encoding and processing of memories, which are disrupted in PTSD. We examined PTSD-associated alterations in 12 hippocampal subfields in relation to global hippocampal shape, and clinical features. METHODS: Case-control cross-sectional studies of U.S. military veterans (n = 282) from the Iraq and Afghanistan era were grouped into PTSD (n = 142) and trauma-exposed controls (n = 140). Participants underwent clinical evaluation for PTSD and associated clinical parameters followed by MRI at 3 T. Segmentation with FreeSurfer v6.0 produced hippocampal subfield volumes for the left and right CA1, CA3, CA4, DG, fimbria, fissure, hippocampus-amygdala transition area, molecular layer, parasubiculum, presubiculum, subiculum, and tail, as well as hippocampal meshes. Covariates included age, gender, trauma exposure, alcohol use, depressive symptoms, antidepressant medication use, total hippocampal volume, and MRI scanner model. RESULTS: Significantly lower subfield volumes were associated with PTSD in left CA1 (P = 0.01; d = 0.21; uncorrected), CA3 (P = 0.04; d = 0.08; uncorrected), and right CA3 (P = 0.02; d = 0.07; uncorrected) only if ipsilateral whole hippocampal volume was included as a covariate. A trend level association of L-CA1 with PTSD (F4, 221  = 3.32, P = 0.07) is present and the other subfield findings are nonsignificant if ipsilateral whole hippocampal volume is not included as a covariate. PTSD-associated differences in global hippocampal shape were nonsignificant. CONCLUSIONS: The present finding of smaller hippocampal CA1 in PTSD is consistent with model systems in rodents that exhibit increased anxiety-like behavior from repeated exposure to acute stress. Behavioral correlations with hippocampal subfield volume differences in PTSD will elucidate their relevance to PTSD, particularly behaviors of associative fear learning, extinction training, and formation of false memories.


Assuntos
Região CA1 Hipocampal/patologia , Hipocampo/patologia , Transtornos de Estresse Pós-Traumáticos/patologia , Veteranos , Adulto , Região CA1 Hipocampal/diagnóstico por imagem , Estudos de Casos e Controles , Estudos Transversais , Feminino , Hipocampo/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Transtornos de Estresse Pós-Traumáticos/diagnóstico por imagem
3.
Stem Cells Transl Med ; 6(12): 2071-2078, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-29080265

RESUMO

Cerebral palsy (CP) is a condition affecting young children that causes lifelong disabilities. Umbilical cord blood cells improve motor function in experimental systems via paracrine signaling. After demonstrating safety, we conducted a phase II trial of autologous cord blood (ACB) infusion in children with CP to test whether ACB could improve function (ClinicalTrials.gov, NCT01147653; IND 14360). In this double-blind, placebo-controlled, crossover study of a single intravenous infusion of 1-5 × 107 total nucleated cells per kilogram of ACB, children ages 1 to 6 years with CP were randomly assigned to receive ACB or placebo at baseline, followed by the alternate infusion 1 year later. Motor function and magnetic resonance imaging brain connectivity studies were performed at baseline, 1, and 2 years post-treatment. The primary endpoint was change in motor function 1 year after baseline infusion. Additional analyses were performed at 2 years. Sixty-three children (median age 2.1 years) were randomized to treatment (n = 32) or placebo (n = 31) at baseline. Although there was no difference in mean change in Gross Motor Function Measure-66 (GMFM-66) scores at 1 year between placebo and treated groups, a dosing effect was identified. In an analysis 1 year post-ACB treatment, those who received doses ≥2 × 107 /kg demonstrated significantly greater increases in GMFM-66 scores above those predicted by age and severity, as well as in Peabody Developmental Motor Scales-2 Gross Motor Quotient scores and normalized brain connectivity. Results of this study suggest that appropriately dosed ACB infusion improves brain connectivity and gross motor function in young children with CP. Stem Cells Translational Medicine 2017;6:2071-2078.


Assuntos
Transfusão de Sangue/métodos , Paralisia Cerebral/terapia , Conectoma , Sangue Fetal/transplante , Destreza Motora , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Movimento
4.
J Prim Health Care ; 8(2): 164-71, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27477559

RESUMO

BACKGROUND Proton pump inhibitors (PPIs) are often used inappropriately, without an indication, or for longer durations than recommended. Few tools exist to guide reassessment of their continued use and deprescribing if required. We aimed to reduce inappropriate drug use by developing and implementing a PPI deprescribing tool and process in a family medicine unit. ASSESSMENT OF PROBLEM Primary care providers of adults taking a PPI for 8 weeks with an upcoming periodic health examination were reminded to reassess therapy via electronic medical record (EMR) messaging. A PPI Deprescribing Tool was uploaded into the EMR as a second reminder and to guide reassessment and deprescribing where indicated. Ten weeks after the examination a chart review assessed changes to PPI use. A follow up survey of providers assessed the utility and barriers to implementing the Deprescribing Tool. RESULTS Forty-three of 46 patients on PPIs (93%) had their PPI reassessed, resulting in 11 patients (26%) having their PPI deprescribed. Strategies for Improvement Routine reassessment of long-term medications is often overlooked because of extensive demands on primary care providers' time. Deprescribing likely improved because potentially eligible patients were identified to the provider and a tool was provided at the time of the encounter to guide the deprescribing process. LESSONS Reassessment and deprescribing of PPIs can be supported by implementing a standardised process and use of guidance tools for clinicians. Providers found the timely and selective reminder message to deprescribe the most useful component of the intervention. KEYWORDS proton pump inhibitor; deprescribing; reassessment; primary care; medication therapy management; gastroesophageal reflux disease.


Assuntos
Desprescrições , Registros Eletrônicos de Saúde/organização & administração , Refluxo Gastroesofágico/tratamento farmacológico , Atenção Primária à Saúde/organização & administração , Inibidores da Bomba de Prótons/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , Atitude do Pessoal de Saúde , Feminino , Fidelidade a Diretrizes , Humanos , Masculino , Pessoa de Meia-Idade , Guias de Prática Clínica como Assunto , Inibidores da Bomba de Prótons/administração & dosagem , Melhoria de Qualidade/organização & administração , Sistemas de Alerta
5.
Heart Lung Circ ; 16(6): 410-5, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17512248

RESUMO

OBJECTIVE: This retrospective study was designed to assess the early morbidity and mortality as well as long-term mortality of combined aortic-mitral valve procedures at a single centre. METHODS: Patients were identified by analysing the intensive care and perfusion databases, from 1989 to 2003, with 113 receiving aortic-mitral valve procedures. Eighty-four percent of patients received a mechanical bileaflet valve. Survival was assessed using a Kaplan-Meier method, and determinants of survival with the Cox proportional hazards model. RESULTS: There were 57 men and 56 women, median age 59 (18-84) years. The 30-day mortality was 9% (n=10). This cohort contained a number of high risk patients, 38% were classified as New York Heart Association class IV, 33.5% had at least moderate ventricular impairment, 20% were redo procedures and 17% urgent procedures. Survival estimates at 5 and 10 years were 85% (0.76-0.90) and 65% (0.49-0.77), respectively. Multivariate pre-operative predictors of death included renal dysfunction (creatinine >200 micromol/L) and hypertension. Rheumatic aetiology was associated with improved survival. CONCLUSION: This study shows acceptable short and long-term survival in patients undergoing combined aortic-mitral valve surgical procedures at a single centre. Renal impairment and hypertension were associated with a poorer long-term prognosis and rheumatic aetiology was associated with improved survival. Age, LVEF and NYHA class were not associated with a worse outcome. This may affect future decision making in light of an aging population.


Assuntos
Valva Aórtica/cirurgia , Doenças das Valvas Cardíacas/mortalidade , Doenças das Valvas Cardíacas/cirurgia , Implante de Prótese de Valva Cardíaca/mortalidade , Valva Mitral/cirurgia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Valva Aórtica/patologia , Estudos de Coortes , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Valva Mitral/patologia , Estudos Retrospectivos , Análise de Sobrevida
6.
Asia Pac J Clin Nutr ; 10(3): 212-5, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11708311

RESUMO

Studies of the therapeutic efficacy of coenzyme Q10 (CoQ10) have been confounded by the variable bioavailability of numerous CoQ10 preparations. The aims of the present study were to determine the early serum levels attained by two different preparations of CoQ10, a soybean oil-based preparation and a complex micelle emulsion and to assess whether these preparations of oral CoQ10 influence plasma lipid profiles. Twelve healthy individuals received 300 mg CoQ10 daily of either preparation for 7 days in a double-blind cross-over design with a 21-day washout period. Blood samples to determine serum levels of CoQ10 and lipids were taken at baseline, after 24 h and 7 days. Both preparations induced significant increases in serum CoQ10 levels at 24 h and 7 days. These were for soy oil: baseline 0.27 +/- 0.03 mol/L, 24 h 0.50 +/- 0.04 mol/L (180%) and 7 days 0.80 +/- 0.05 mol/L (291%), mean +/- SEM: for emulsion: baseline 0.29 +/- 0.03 mol/L, 24 h 0.45 +/- 0.03 mol/L (150%) and 7 days 0.79 +/- 0.06 mol/L (270%). There were no significant differences between CoQ10 levels for the two preparations at either time point. There was no change in any of the serum lipids following the 7 days treatment. We conclude that administration of either a soy oil suspension or a complex emulsion of CoQ10 increases serum levels to the therapeutic range within 1 week.


Assuntos
Antioxidantes/farmacologia , Lipídeos/sangue , Ubiquinona/análogos & derivados , Ubiquinona/farmacologia , Adulto , Antioxidantes/análise , Antioxidantes/farmacocinética , Disponibilidade Biológica , Coenzimas , Estudos Cross-Over , Método Duplo-Cego , Emulsões , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Óleo de Soja , Resultado do Tratamento , Ubiquinona/sangue , Ubiquinona/farmacocinética
7.
Mol Microbiol ; 42(1): 145-57, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11679074

RESUMO

Adaptive responses of bacteria that involve sensing the presence of other bacteria are often critical for proliferation and the expression of virulence characteristics. The autoinducer II (AI-2) pathway has recently been shown to be a mechanism for sensing other bacteria that is highly conserved among diverse bacterial species, including Gram-positive pathogens. However, a role for this pathway in the regulation of virulence factors in Gram-positive pathogens has yet to be established. In this study, we have inactivated luxS, an essential component of the AI-2 pathway, in the Gram-positive pathogen Streptococcus pyogenes. Analyses of the resulting mutants revealed the aberrant expression of several virulence properties that are regulated in response to growth phase, including enhanced haemolytic activity, and a dramatic reduction in the expression of secreted proteolytic activity. This latter defect was associated with a reduced ability to secrete and process the precursor of the cysteine protease (SpeB) as well as a difference in the timing of expression of the protease. Enhanced haemolytic activity of the luxS strain was also shown to be linked with an increased expression of the haemolysin S-associated gene sagA. Disruptions of luxS in these mutants also produced a media-dependent growth defect. Finally, an allelic replacement analysis of an S. pyogenes strain with a naturally occurring insertion of IS1239 in luxS suggested a mechanism for modulation of virulence during infection. Results from this study suggest that luxS makes an important contribution to the regulation of S. pyogenes virulence factors.


Assuntos
Proteínas de Bactérias/genética , Homosserina/análogos & derivados , Streptococcus pyogenes/fisiologia , Animais , Proteínas de Bactérias/metabolismo , Liases de Carbono-Enxofre , Meios de Cultura , Cisteína Endopeptidases/genética , Cisteína Endopeptidases/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Homosserina/genética , Homosserina/metabolismo , Humanos , Lactonas/metabolismo , Mutação , Streptococcus pyogenes/genética , Streptococcus pyogenes/crescimento & desenvolvimento , Streptococcus pyogenes/patogenicidade , Estreptolisinas/metabolismo , Transcrição Gênica , Virulência/genética
8.
Appl Environ Microbiol ; 67(10): 4685-93, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11571173

RESUMO

Vibrio cholerae is recognized as a leading human waterborne pathogen. Traditional diagnostic testing for Vibrio is not always reliable, because this bacterium can enter a viable but nonculturable state. Therefore, nucleic acid-based tests have emerged as a useful alternative to traditional enrichment testing. In this article, a TaqMan PCR assay is presented for quantitative detection of V. cholerae in pure cultures, oysters, and synthetic seawater. Primers and probe were designed from the nonclassical hemolysin (hlyA) sequence of V. cholerae strains. This probe was applied to DNA from 60 bacterial strains comprising 21 genera. The TaqMan PCR assay was positive for all of the strains of V. cholerae tested and negative for all other species of Vibrio tested. In addition, none of the other genera tested was amplified with the TaqMan primers and probe used in this study. The results of the TaqMan PCR with raw oysters and spiked with V. cholerae serotypes O1 and O139 were comparable to those of pure cultures. The sensitivity of the assay was in the range of 6 to 8 CFU g(-1) and 10 CFU ml(-1) in spiked raw oyster and synthetic seawater samples, respectively. The total assay could be completed in 3 h. Quantification of the Vibrio cells was linear over at least 6 log units. The TaqMan probe and primer set developed in this study can be used as a rapid screening tool for the presence of V. cholerae in oysters and seawater without prior isolation and characterization of the bacteria by traditional microbiological methods.


Assuntos
Ostreidae/microbiologia , Reação em Cadeia da Polimerase/métodos , Água do Mar/microbiologia , Taq Polimerase/metabolismo , Vibrio cholerae/isolamento & purificação , Animais , Meios de Cultura , Sondas de DNA , DNA Bacteriano/análise , Sensibilidade e Especificidade , Fatores de Tempo , Vibrio cholerae/classificação , Vibrio cholerae/genética
9.
Br J Surg ; 88(7): 931-4, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11442522

RESUMO

BACKGROUND: The main aim of this study was to evaluate outcome in patients undergoing open inguinal hernia repair with either polypropylene mesh or nylon darn. METHODS: This was a randomized prospective trial of patients who underwent the procedure with follow-up at 1 week, 6 weeks and 1 year. RESULTS: One hundred men underwent 105 repairs by consultant surgeons and registrars; there were 54 mesh and 51 nylon repairs. Demographics in both groups were similar at the start of the trial, as were the types of hernia. The pain scores at 24, 48 and 72 h were similar, as was the duration of analgesia requirement. There were no differences in early or late complications. Return to normal activity in each group was also similar, with a mean time of 5 weeks. The recurrence rate in both groups was comparable: 4 per cent after mesh repair and 4 per cent after darn repair at 1-year review. CONCLUSION: Open inguinal hernia repair with a nylon darn was equivalent to polypropylene mesh with respect to early measures of postoperative outcome and recurrence at 1 year.


Assuntos
Hérnia Inguinal/cirurgia , Nylons , Polipropilenos , Telas Cirúrgicas , Adulto , Idoso , Idoso de 80 Anos ou mais , Analgésicos/uso terapêutico , Hérnia Inguinal/reabilitação , Humanos , Masculino , Pessoa de Meia-Idade , Medição da Dor , Dor Pós-Operatória/etiologia , Estudos Prospectivos , Recidiva , Técnicas de Sutura
10.
J Food Prot ; 63(9): 1231-9, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10983798

RESUMO

Fresh catfish (Ictalurus punctatus) fillets are known to be contaminated with a large number of spoilage and pathogenic bacteria. The Grovac method, a new patented (U.S. 5,543,163) process, was evaluated for its efficacy in reducing the number of pathogens and spoilage microorganisms associated with food. This process involves using a processing solution containing ascorbic acid (AA) and sodium chloride (NaCl), vacuum, and tumbling. A total of 51 bacterial isolates were isolated and identified from whole catfish and catfish fillets using both selective and nonselective media, phenotypic tests, and the Vitek identification system. Psychrotrophic foodborne pathogens included: Aeromonas hydrophila, Escherichia coli, Listeria sp., Plesiomonas shigelloides, Proteus sp., Staphylococcus aureus, and Vibrio parahaemolyticus. High aerobic plate counts (2.6 x 10(7) CFU/g) for catfish fillets indicated that fillets were heavily contaminated during processing of catfish. The Grovac process showed that various treatment combinations of AA and NaCl resulted in a 1.2 to 2.3 CFU/g log reduction of microbial counts associated with catfish fillets. The effectiveness of the process may be related to the synergistic effect of tumbling, AA, NaCl, and vacuum. These results suggested that the Grovac process could be used as an alternative processing procedure to reduce microbial populations associated with catfish fillets and may be useful to improve the shelf-life and food safety of the product. Microbiological data from this study will be used for the development of a hazard analysis for the implementation of the hazard analysis critical control point program for processed catfish fillets.


Assuntos
Bactérias/isolamento & purificação , Produtos Pesqueiros/microbiologia , Conservação de Alimentos/métodos , Ictaluridae/microbiologia , Animais , Ácido Ascórbico/farmacologia , Contagem de Colônia Microbiana , Meios de Cultura/química , Cloreto de Sódio/farmacologia , Vácuo
11.
J Food Prot ; 63(12): 1687-96, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11131892

RESUMO

Refrigerated vacuum-packaged storage has been shown to increase significantly the shelf life of fresh fish and seafood products, but the effect, if any, on the outgrowth and toxin production of Clostridium botulinum type E on cooked crawfish is unknown. Microflora associated with live crawfish reflect the microbial populations of the harvest water and sediments in which they are living. The presence or absence of specific pathogens in either vacuum-packaged or air-permeable bags of cooked crawfish have not been thoroughly evaluated. This study evaluates the potential survival and outgrowth of biological hazards in both vacuum-packaged and air-permeable-packaged cooked crawfish held at 4 and 10 degrees C for 30 days. During shelf-life studies of vacuum-packaged and air-permeable-bagged cooked crawfish, a total of 31 bacterial species were isolated and identified from crawfish samples using both selective and nonselective media. The only pathogens isolated from both vacuum-packed and air-permeable bags of processed crawfish samples during shelf-life studies were strains of Aeromonas hydrophila and Staphylococcus aureus. C. botulinum type E and Clostridium perfringens species were not isolated from any of the uninoculated crawfish samples. Cooked crawfish were inoculated with 10(3) C. botulinum type E spores per g of crawfish tail meat to determine whether cooked crawfish tails would support the growth of C. botulinum type E strains and produce toxin at refrigerated temperatures. Spore-inoculated crawfish tails were vacuum packaged in both a high barrier film and an air-permeable bag and stored at 4 degrees C and 10 degrees C for 30 days. C. botulinum toxin E was not detected in any of the spore-inoculated packages throughout the shelf-life study until day 30. Microbiological data from this study should be useful in the development and implementation of the hazard analysis and critical control point plans for processed crawfish tails.


Assuntos
Astacoidea/microbiologia , Toxinas Botulínicas/biossíntese , Clostridium botulinum/metabolismo , Embalagem de Alimentos/métodos , Conservação de Alimentos , Alimentos Marinhos/microbiologia , Ar , Animais , Toxinas Botulínicas/análise , Clostridium botulinum/isolamento & purificação , Microbiologia de Alimentos , Controle de Qualidade , Temperatura , Fatores de Tempo , Vácuo , Microbiologia da Água
12.
EMBO J ; 17(21): 6263-75, 1998 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-9799235

RESUMO

The ability of numerous microorganisms to cause disease relies upon the highly regulated expression of secreted proteinases. In this study, mutagenesis with a novel derivative of Tn4001 was used to identify genes required for the expression of the secreted cysteine proteinase (SCP) of the pathogenic Gram-positive bacterium Streptococcus pyogenes. Designated as Rop loci (regulation of proteinase), ropB is a rgg-like transcriptional activator required for transcription of the gene which encodes the proteinase. In contrast, ropA contributes post-transcriptionally to the secretion and processing of SCP and encodes a homologue of Trigger Factor, a peptidyl-prolyl isomerase and putative chaparone which is highly conserved in most bacterial species, but of unknown function. Analysis of additional ropA mutants demonstrated that RopA acts both to assist in targeting SCP to the secretory pathway and to promote the ability of the proprotein to establish an active conformation upon secretion. This latter function was dependent upon the peptidyl-prolyl isomerase domain of RopA and mutants that lacked this domain exhibited a bipartite deficiency manifested as a kinetic defect in autologous processing of the proprotein to the mature proteinase, and as a catalytic defect in the mature proteinase. These results provide insight into the function of Trigger Factor, the regulation of proteinase activity and the mechanism of secretion in Gram-positive bacteria.


Assuntos
Cisteína Endopeptidases/genética , Proteínas de Ligação a DNA , Regulação Bacteriana da Expressão Gênica/genética , Regulação Enzimológica da Expressão Gênica/genética , Peptidilprolil Isomerase/metabolismo , Streptococcus pyogenes/enzimologia , Streptococcus pyogenes/genética , Transativadores , Sequência de Aminoácidos , Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/metabolismo , Proteínas de Bactérias/metabolismo , Clonagem Molecular , Cisteína Endopeptidases/metabolismo , Elementos de DNA Transponíveis/genética , Dados de Sequência Molecular , Mutagênese Insercional/genética , RNA Mensageiro/genética , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Fatores de Transcrição/genética , Transcrição Gênica/genética
13.
Anal Chem ; 70(9): 1743-8, 1998 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-21651268

RESUMO

An integrated epifocal and evanescent-wave optical microscope has been developed for real-time observation and bond cleavage studies of single DNA molecules. Large genomic DNA is stretched in a laminar flow stream and is immobilized on a polylysine-coated glass surface by strong electrostatic interactions. Unlike previous single-molecule dynamics and single-enzyme studies, this work takes advantage of the elastic nature of double-stranded DNA and measures DNA relaxation events that are triggered by two phosphodiester (P-O) bond breaks. The ability to follow chemical reactions on individual DNA molecules opens new possibilities for DNA mapping and for studying DNA-protein interactions.

15.
J Dairy Sci ; 76(6): 1506-13, 1993 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8326023

RESUMO

Propionibacterium thoenii strain P127, which produces the bacteriocin propionicin PLG-1, was grown in a skim milk medium and produced bacteriocin in that medium. No bacteriocin activity was detected in skim milk medium in which strain P127-1, a bacteriocin-negative variant of strain P127, had been grown. Five psychrotrophic spoilage or pathogenic organisms (one strain each of Listeria monocytogenes, Pseudomonas fluorescens, Vibrio parahaemolyticus, Yersinia enterocolitica, and one strain of Corynebacterium sp.) were incubated for 24 h in laboratory medium, nonfermented skim milk, and skim milk that had been fermented by strain P127 or P127-1. Strains were inhibited only in the skim milk fermented by strain P127, as evidenced by loss in numbers of viable cells after 24 h at 10 degrees C and less growth than in other media after 24 h at optimal growth temperatures. Growth of selected strains was delayed or slowed during prolonged incubation (21 d) at 10 degrees C. Propionicin PLG-1 shows promise as a preservative for food products.


Assuntos
Bactérias/efeitos dos fármacos , Bacteriocinas/farmacologia , Leite , Propionibacterium/metabolismo , Animais , Bacteriocinas/biossíntese , Corynebacterium/efeitos dos fármacos , Meios de Cultura , Fermentação , Propionibacterium/crescimento & desenvolvimento , Pseudomonas fluorescens/efeitos dos fármacos , Vibrio parahaemolyticus/efeitos dos fármacos , Yersinia enterocolitica/efeitos dos fármacos
16.
Appl Environ Microbiol ; 59(1): 83-8, 1993 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8439170

RESUMO

Production of propionicin PLG-1 by Propionibacterium thoenii P127 was pH dependent, with maximal activity detected in supernatants of cultures grown at pH 7.0 Propionicin PLG-1 was purified by ion-exchange chromatography and isoelectric focusing. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of propionicin PLG-1 purified through isoelectric focusing resolved a protein band with a molecular weight of 10,000. Propionicin PLG-1 was bactericidal to sensitive cells, demonstrating single-hit kinetics. The producing strain harbored a single plasmid (pLG1) with an approximate size of 250 kb. Preliminary data indicate that both propionicin PLG-1 and immunity to the bacteriocin are encoded on the chromosome. Exposure of strain P127 to acriflavine or to N-methyl-N'-nitro-N-nitrosoguanidine yielded isolates that no longer produced bacteriocin activity and isolates that were cured of the plasmid. However, loss of bacteriocin production was not correlated with loss of the plasmid. Isolates cured of the plasmid were phenotypically identical to plasmid-bearing cells in fermentation patterns, pigment production, and growth characteristics.


Assuntos
Bacteriocinas/isolamento & purificação , Propionibacterium/química , Bacteriocinas/biossíntese , Bacteriocinas/farmacologia , Resistência Microbiana a Medicamentos , Eletroforese em Gel de Poliacrilamida , Concentração de Íons de Hidrogênio , Plasmídeos/fisiologia , Propionibacterium/efeitos dos fármacos , Propionibacterium/genética
17.
Appl Environ Microbiol ; 57(3): 701-6, 1991 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16348436

RESUMO

A partially purified bacteriocin produced by Propionibacterium thoenii designated propionicin PLG-1 was found to be active against closely related species and exhibited a broad spectrum of activity against other microorganisms. Propionicin PLG-1 was found to be heat labile, sensitive to several proteolytic enzymes, and stable at pH 3 to 9. Propionicin PLG-1 was isolated from solid medium, partially purified by ammonium sulfate precipitation, and purified further by gel filtration. Gel filtration experiments revealed that bacteriocin PLG-1 was present as two different protein aggregates with apparent molecular weights of more than 150,000 and approximately 10,000. Resolution of these protein aggregates by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed the presence of a protein common to both with an apparent molecular weight of 10,000.

19.
Can Fam Physician ; 36: 1413-5, 1990 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21233898

RESUMO

While the value of continuity of medical care can be debated, colleges of family medicine and residency training programs continue to support the concept. Although teaching hospitals are a poor environment for continuity of care, faculty have a responsibility to ensure that it is taught and, just as importantly, practised in the training centres.

20.
Can Fam Physician ; 35: 1091-2, 1989 May.
Artigo em Inglês | MEDLINE | ID: mdl-21248940

RESUMO

An elderly woman diagnosed as having inoperable adenocarcinoma of the lung with liver metastases complained of extreme agitation within one week of diagnosis and symptomatic treatment. It was difficult to distinguish at first between a possible side-effect of the medication prescribed and the anxiety likely to be associated with the diagnosis of cancer and with an unfavourable prognosis.

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