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1.
Hum Pathol ; 134: 1-18, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36804828

RESUMEN

This study examined PRAME (preferentially expressed antigen in melanoma) expression by immunohistochemistry and reverse transcription quantitative PCR (RT-qPCR) in 202 histologically unequivocal conjunctival melanocytic lesions: 76 nevi, 29 benign melanoses, 25 low-grade conjunctival intraepithelial melanocytic lesions (LGCMIL), 26 high-grade conjunctival melanocytic intraepithelial lesions/in-situ melanoma (HGCMIL), and 46 invasive melanomas. PRAME score 0 was seen in 96% of nevi (73/76), 96% of benign melanoses (28/29), and 88% of LGCMIL (22/25). PRAME score 4 was seen in 50% HGCMIL (13/26) and 76% invasive melanomas (35/46). PRAME score 4 had a sensitivity of 50% and specificity of 100% in differentiating between HGCMIL and benign melanosis/LGCMIL. PRAME score 4 had a sensitivity of 76% and specificity of 100% in differentiating between melanoma and nevi. Relative quantification of PRAME mRNA expression by RT-qPCR was performed on 49 cases (24%): 17 nevi, 3 benign melanoses, 5 LGCMIL, 9 HGCMIL, and 15 invasive melanomas. The analysis generated two distinct groupings with 'high' relative PRAME expression for the HGCMIL and invasive melanoma and 'low/zero' expression for nevi, benign melanosis, and LGCMIL. Thirty-three challenging conjunctival melanocytic lesions that had previous fluorescence in situ hybridization (FISH) analysis were studied: 18 nevi, 12 melanomas in a nevus, 2 nevoid melanomas, and 1 in-situ melanoma. All nevi (100%) showed concordance between negative FISH and PRAME (scores 0-3). Four of 13 melanomas (31%; in-situ, invasive, isolated, and in association with nevus) showed concordance between positive FISH and PRAME score 4. In conclusion, PRAME score 4 has 100% specificity for the diagnosis of HGCMIL and melanoma. PRAME is limited in its sensitivity in the evaluation of challenging melanocytic lesions.


Asunto(s)
Melanoma , Melanosis , Nevo Pigmentado , Nevo , Neoplasias Cutáneas , Humanos , Inmunohistoquímica , Hibridación Fluorescente in Situ , Transcripción Reversa , Melanoma/diagnóstico , Melanoma/genética , Melanoma/metabolismo , Neoplasias Cutáneas/diagnóstico , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/patología , Nevo Pigmentado/diagnóstico , Nevo Pigmentado/genética , Nevo Pigmentado/patología , Melanosis/diagnóstico , Melanosis/genética , Reacción en Cadena de la Polimerasa , Factores de Transcripción/genética , Antígenos de Neoplasias/genética , Antígenos de Neoplasias/análisis , Melanoma Cutáneo Maligno
2.
Ocul Immunol Inflamm ; 31(3): 656-659, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35404734

RESUMEN

PURPOSE: Multiple cases of corneal graft rejection after various vaccinations have been reported over the past decades. Here we described a case of bilateral cystoid macular edema (CME) and endothelial rejection in a DSAEK patient following influenza and varicella vaccines. CASE REPORT: A 72-year-old woman with bilateral Fuch's endothelial dystrophy received bilateral DSAEK surgeries. She received an influenza vaccination and her left visual acuity (VA) decreased due to CME. Half a year later, the patient received a varicella-zoster virus vaccine. 11 days later, she was found to have signs of endothelial graft rejection in both eyes. Unfortunately, her vision further deteriorated despite intensive topical steroid treatment. CONCLUSIONS: In view of the current worldwide efforts on mass vaccination against the COVID-19 pandemic, we suggest an increased use of topical corticosteroids both before and after vaccination may be helpful in reducing this risk.


Asunto(s)
COVID-19 , Varicela , Enfermedades de la Córnea , Herpes Zóster , Vacunas contra la Influenza , Gripe Humana , Edema Macular , Humanos , Femenino , Anciano , Edema Macular/diagnóstico , Edema Macular/tratamiento farmacológico , Edema Macular/etiología , Gripe Humana/prevención & control , Rechazo de Injerto/diagnóstico , Rechazo de Injerto/etiología , Pandemias , Enfermedades de la Córnea/cirugía , Vacunas contra la Influenza/efectos adversos , Vacunación/efectos adversos
4.
World J Surg ; 45(3): 790-796, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33219416

RESUMEN

BACKGROUND: Post-operative management after phaeochromocytoma resection includes monitoring of blood pressure and blood sugar, and vigilance for haemorrhage. Guidelines recommend 24 h of continuous blood pressure monitoring, usually necessitating HDU/ICU admission. We hypothesised that most patients undergoing phaeochromocytoma resection do not require post-operative HDU/ICU admission. We aim to describe current Australian and New Zealand perioperative management of phaeochromocytoma and determine whether it is safe to omit HDU/ICU care for most patients. METHODS: We collected retrospective data on patients undergoing excision of phaeochromocytoma in 12 centres around Australia and New Zealand between 2007 and 2019. Data collected included preoperative medical management, anaesthetic management, vasopressor support, HDU/ICU admission and complications. RESULTS: A total of 223 patients were included in the study, 173 (77%) of whom were admitted to HDU/ICU post-operatively. The group of patients treated in ICU was similar to the group of patients treated on the ward in terms of demographic and tumour characteristics, and there were significant differences in the proportion of patients admitted to HDU/ICU between centres. Of patients admitted to ICU, 71 (41%) received vasopressor support. This was weaned within 24 h in 55 (77%) patients. Patients with larger tumours (> 6 cm) and a transfusion requirement are more likely to require prolonged inotropic support. Among patients admitted to the ward, there were no complications that required escalation of care. CONCLUSIONS: Although not widespread practice in Australia and New Zealand, it appears safe for the majority of patients undergoing minimally invasive resection of phaeochromocytoma to be admitted to the ward post-operatively.


Asunto(s)
Neoplasias de las Glándulas Suprarrenales , Unidades de Cuidados Intensivos , Feocromocitoma , Neoplasias de las Glándulas Suprarrenales/cirugía , Australia , Humanos , Nueva Zelanda , Feocromocitoma/cirugía , Estudios Retrospectivos
5.
J Neurol Phys Ther ; 44(4): 268-274, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-32459723

RESUMEN

BACKGROUND AND PURPOSE: Rhythmic auditory cueing and treadmill walking can improve spatiotemporal gait parameters through entrainment of movement patterns. Careful selection of cue frequencies is necessary if treadmill walking is to be employed, because cadence and step length are differentially affected by walking on a treadmill and overground. The purpose of this study was to describe the treatment of gait impairments for individuals with Parkinson disease, using strategically selected rhythmic auditory cue frequencies on both a treadmill and overground. CASE DESCRIPTION: Three individuals with Hoehn & Yahr stage 2 Parkinson disease participated in this case series. INTERVENTION: All participants completed 6 weeks of gait training, in which each session employed rhythmic auditory cueing during treadmill-based gait training followed by overground gait training. We provided targeted rhythmic auditory cueing with a metronome set to 85% and 115% of their self-selected cadence for treadmill and overground training, respectively. We performed clinical tests of gait and balance prior to, midway, and following training, and at a 3-month follow-up. OUTCOMES: All participants improved overground gait speed (participant 1: +0.27 m/s; participant 2: +0.20 m/s; and participant 3: +0.18 m/s) and stride length (15.7 ± 4.17 cm) with small changes to cadence. Likewise, there were only small changes in balance. DISCUSSION: We hypothesize that the large improvements in gait speed are due to the concomitant increases in stride length. Further research is needed to test the effect of targeted rhythmic auditory cueing during treadmill and overground gait.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A309).


Asunto(s)
Enfermedad de Parkinson , Señales (Psicología) , Prueba de Esfuerzo , Marcha , Humanos , Caminata
6.
Curr Zool ; 64(5): 593-601, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-30323838

RESUMEN

Insular populations are particularly vulnerable to the effects of stochastic events, epidemics, and loss of genetic diversity due to inbreeding and genetic drift. The development of successful management options will require accurate baseline data, establishment of clear objectives, and finally monitoring and implementation of corrective measures, if and when required. This study assessed management options for the genetic rehabilitation of highly inbred woylies obtained from wildlife rehabilitation centers. The study generated genetic data for the woylie Bettongia penicillata from a conservation reserve and calculated measures of genetic diversity and individual relatedness. These data were fed into a population viability analysis (PVA) to test genetic outcomes in relation to different management actions. We demonstrated that a careful selection of the founder cohort produced a population with an expected heterozygosity of ∼70% for a window of approximately 10 years. A proposal to increase the size of the reserve available to the colony was shown to almost double the time at which the colony would retain heterozygosity levels of ≥ 70%. Additionally, developing a regular program of supplementation of unrelated woylies would result in a further improvement in their genetic value. This study demonstrated how the application of molecular techniques in combination with PVA can be beneficial for the management of rehabilitated wildlife otherwise considered of little conservation value. This approach can be applied to the management of breeding programs, but also to small, closed populations such as those found on islands, fenced enclosures, insurance populations, and in zoological collections.

7.
N Engl J Med ; 377(4): 399, 2017 07 27.
Artículo en Inglés | MEDLINE | ID: mdl-28745984
8.
BMJ Case Rep ; 20152015 Sep 17.
Artículo en Inglés | MEDLINE | ID: mdl-26385915

RESUMEN

A 28-year-old woman, a park ranger, developed acute Q fever with associated sepsis, profound jaundice, disseminated intravascular coagulation and multiorgan failure necessitating prolonged admission to the intensive care unit for ventilatory support. She recovered fully and remains well 4 years later.


Asunto(s)
Macropodidae/microbiología , Enfermedades Profesionales/microbiología , Fiebre Q/diagnóstico , Fiebre Q/etiología , Zoonosis/microbiología , Adulto , Animales , Australia/epidemiología , Diagnóstico Diferencial , Femenino , Estudios de Seguimiento , Humanos , Enfermedades Profesionales/sangre , Enfermedades Profesionales/diagnóstico , Enfermedades Profesionales/terapia , Fiebre Q/sangre , Fiebre Q/terapia , Resultado del Tratamiento , Zoonosis/sangre , Zoonosis/diagnóstico , Zoonosis/terapia
9.
Perit Dial Int ; 35(2): 222-8, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-24584597

RESUMEN

BACKGROUND: There is limited available evidence regarding the role of monitoring serum vancomycin concentrations during treatment of peritoneal dialysis (PD)-associated peritonitis. METHODS: A total of 150 PD patients experiencing 256 episodes of either gram-positive or culture-negative peritonitis were included to investigate the relationship between measured serum vancomycin within the first week and clinical outcomes of cure, relapse, repeat or recurrence of peritonitis, catheter removal, temporary or permanent transfer to hemodialysis, hospitalization and death. RESULTS: Vancomycin was used as an initial empiric antibiotic in 54 gram-positive or culture-negative peritonitis episodes among 34 patients. The median number of serum vancomycin level measurements in the first week was 3 (interquartile range; IQR 1 - 4). The mean day-2 vancomycin level, measured in 34 (63%) episodes, was 17.5 ± 5.2 mg/L. Hospitalized patients were more likely to have serum vancomycin levels measured on day 2 and ≥ 3 measurements in the first week. The peritonitis cure rates were similar between patients with < 3 and ≥ 3 measurements in the first week (77% vs 57%, p = 0.12) and if day-2 vancomycin levels were measured or not (68% vs 65%, p = 0.84). The average day-2 (18.0 ± 5.9 vs 16.6 ± 3.2, p = 0.5), first-week average (18.6 ± 5.1 vs 18.6 ± 4.3, p = 0.9) and nadir (14.5 ± 4.1 vs 13.6 ± 4.2, p = 0.5) vancomycin levels were comparable in patients who did or did not achieve peritonitis cure. Similar results were observed for all other clinical outcomes. CONCLUSION: The clinical outcomes of gram-positive and culture-negative peritonitis episodes are not associated with either the frequency or levels of serum vancomycin measurements in the first week of treatment when vancomycin is dosed according to International Society for Peritoneal Dialysis (ISPD) Guidelines.


Asunto(s)
Antibacterianos/uso terapéutico , Monitoreo de Drogas , Fallo Renal Crónico/terapia , Diálisis Peritoneal/efectos adversos , Peritonitis/tratamiento farmacológico , Vancomicina/uso terapéutico , Adulto , Anciano , Antibacterianos/sangre , Estudios de Cohortes , Femenino , Humanos , Fallo Renal Crónico/sangre , Masculino , Persona de Mediana Edad , Peritonitis/sangre , Peritonitis/etiología , Resultado del Tratamiento , Vancomicina/sangre
10.
Nephrol Dial Transplant ; 29(12): 2277-86, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25061124

RESUMEN

BACKGROUND: Alport syndrome is a rare inheritable renal disease. Clinical outcomes for patients progressing to end-stage kidney disease (ESKD) are not well described. METHODS: This study aimed to investigate the characteristics and clinical outcomes of patients from Australia and New Zealand commencing renal replacement therapy (RRT) for ESKD due to Alport syndrome between 1965 and 1995 (early cohort) and between 1996 and 2010 (contemporary cohort) compared with propensity score-matched, RRT-treated, non-Alport ESKD controls. RESULTS: A total of 58 422 patients started RRT during this period of which 296 (0.5%) patients had Alport ESKD. In the early cohort, Alport ESKD was associated with superior dialysis patient survival [adjusted hazard ratio (HR): 0.41, 95% confidence interval (CI): 0.20-0.83, P = 0.01], renal allograft survival (HR: 0.74, 95% CI: 0.54-1.01, P = 0.05) and renal transplant patient survival (HR: 0.43, 95% CI: 0.28-0.66, P < 0.001) compared with controls. In the contemporary cohort, no differences were observed between the two groups for dialysis patient survival (HR: 1.42, 95% CI: 0.65-3.11, P = 0.38), renal allograft survival (HR: 1.01, 95% CI: 0.57-1.79, P = 0.98) or renal transplant patient survival (HR: 0.67, 95% CI: 0.26-1.73, P = 0.41). One Alport patient (0.4%) had post-transplant anti-glomerular basement membrane (anti-GBM) disease. Four female and 41 male Alport patients became parents on RRT with generally good neonatal outcomes. CONCLUSION: Alport syndrome patients experienced comparable dialysis and renal transplant outcomes to matched non-Alport ESKD controls in the contemporary cohort due to relatively greater improvements in outcomes for non-Alport ESKD patients over time. Post-transplant anti-GBM disease was rare.


Asunto(s)
Fallo Renal Crónico/cirugía , Trasplante de Riñón , Nefritis Hereditaria/complicaciones , Sistema de Registros , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Australia/epidemiología , Niño , Preescolar , Femenino , Estudios de Seguimiento , Supervivencia de Injerto , Humanos , Incidencia , Lactante , Recién Nacido , Fallo Renal Crónico/epidemiología , Fallo Renal Crónico/etiología , Masculino , Persona de Mediana Edad , Nefritis Hereditaria/epidemiología , Nueva Zelanda/epidemiología , Pronóstico , Estudios Retrospectivos , Tasa de Supervivencia/tendencias , Adulto Joven
11.
Nephrology (Carlton) ; 19 Suppl 1: 22-6, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24460647

RESUMEN

We present a case of an unsensitized patient with end-stage kidney disease secondary to atypical haemolytic uremic syndrome (aHUS) with mutations in CD46/MCP and CFH who developed severe, intractable antibody-mediated rejection (ABMR) unresponsive to therapy post kidney transplantation. There were no haematological features of thrombotic microangiopathy. The patient received standard induction therapy and after an initial fall in serum creatinine, severe ABMR developed in the setting of urosepsis. Despite maximal therapy with thymoglobulin, plasma exchange and methylprednisolone, rapid graft loss resulted and transplant nephrectomy was performed. Luminex at 4 weeks showed a new DSA and when repeated after nephrectomy showed antibodies to each of the 5 mismatched antigens with high MFI. The rate of recurrence of disease in patients with aHUS referred for transplantation is 50% and is associated with a high rate of graft loss. It is dependent in part on the nature of the mutation with circulating factors CFH and CFI more likely to cause recurrent disease than MCP which is highly expressed in the kidney. There is increasing interest in the role of complement in the development and propagation of ABMR via terminal complement activation. This case suggesting that dysregulation of the alternative complement pathway within the transplant kidney may have contributed to the severe AMR. Very little is known about the impact of complement dysregulation and the development of anti HLA antibodies however the strength of HLA antibody formation was prominent in this case.


Asunto(s)
Síndrome Hemolítico Urémico Atípico/complicaciones , Rechazo de Injerto/complicaciones , Rechazo de Injerto/inmunología , Trasplante de Riñón , Complicaciones Posoperatorias/inmunología , Adulto , Anticuerpos/inmunología , Femenino , Humanos , Índice de Severidad de la Enfermedad
12.
PLoS One ; 6(3): e17559, 2011 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-21408176

RESUMEN

BACKGROUND: Aquaporin-4 (AQP4) constitutes the principal water channel in the brain and is clustered at the perivascular astrocyte endfeet. This specific distribution of AQP4 plays a major role in maintaining water homeostasis in the brain. A growing body of evidence points to a role of the dystroglycan complex and its interaction with perivascular laminin in the clustering of AQP4 at perivascular astrocyte endfeet. Indeed, mice lacking components of this complex or in which laminin-dystroglycan interaction is disrupted show a delayed onset of brain edema due to a redistribution of AQP4 away from astrocyte endfeet. It is therefore important to identify inhibitory drugs of laminin-dependent AQP4 clustering which may prevent or reduce brain edema. METHODOLOGY/PRINCIPAL FINDINGS: In the present study we used primary rat astrocyte cultures to screen a library of >3,500 chemicals and identified 6 drugs that inhibit the laminin-induced clustering of dystroglycan and AQP4. Detailed analysis of the inhibitory drug, chloranil, revealed that its inhibition of the clustering is due to the metalloproteinase-2-mediated ß-dystroglycan shedding and subsequent loss of laminin interaction with dystroglycan. Furthermore, chemical variants of chloranil induced a similar effect on ß-dystroglycan and this was prevented by the antioxidant N-acetylcysteine. CONCLUSION/SIGNIFICANCE: These findings reveal the mechanism of action of chloranil in preventing the laminin-induced clustering of dystroglycan and AQP4 and validate the use of high-throughput screening as a tool to identify drugs that modulate AQP4 clustering and that could be tested in models of brain edema.


Asunto(s)
Acuaporina 4/metabolismo , Astrocitos/metabolismo , Distroglicanos/metabolismo , Ensayos Analíticos de Alto Rendimiento/métodos , Laminina/farmacología , Bibliotecas de Moléculas Pequeñas/farmacología , Animales , Astrocitos/citología , Astrocitos/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Cloranilo/química , Cloranilo/farmacología , Flunarizina/farmacología , Gelatina/metabolismo , Humanos , Ratones , Microscopía , Compuestos Orgánicos/farmacología , Ratas , Ratas Sprague-Dawley , Especies Reactivas de Oxígeno/metabolismo , Reproducibilidad de los Resultados , Factores de Tiempo , Inhibidores Tisulares de Metaloproteinasas/metabolismo
13.
Res Q Exerc Sport ; 80(2): 303-12, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19650396

RESUMEN

We examined whether perceived competence moderated the relationships between implicit theories, 2 x 2 achievement goals, and intrinsic motivation for sports and physical activity. We placed 309 university students into high and moderate perceived competence groups. When perceived competence was high, entity beliefs did not predict the performance-avoidance goal; yet when perceived competence was moderately low, entity beliefs did predict this goal. The mastery-avoidance goal had no relationship with intrinsic motivation when perceived competence was high, but had a significant negative relationship when perceived competence was moderately low. Our findings highlight the importance of reexamining the role of perceived competence when studying implicit beliefs and the 2 x 2 achievement goals.


Asunto(s)
Rendimiento Atlético/normas , Ejercicio Físico , Objetivos , Motivación , Autoeficacia , Deportes , Adolescente , Adulto , Femenino , Humanos , Masculino , Sudoeste de Estados Unidos , Encuestas y Cuestionarios , Universidades , Adulto Joven
14.
Artículo en Inglés | MEDLINE | ID: mdl-16945582

RESUMEN

We have studied micelles comprised of cationic (CTAB) and anionic (SDS) surfactants through the interactions of solution phase anionic disodium fluorescein (DSF) and cationic rhodamine 110 (R110) dyes with perylene sequestered within the micelles. Fluorescence lifetime measurements monitor energy transfer between the nonpolar optical donor within the micelle and ionic probes in the surrounding solution. The efficiency of this process is mediated by the extent to which the ionic dyes interact with the micelle palisade layer, and our fluorescence lifetime data allow us to determine the association constants for acceptor-micelle interactions.


Asunto(s)
Aniones/química , Cationes/química , Micelas , Tensoactivos/química , Cetrimonio , Compuestos de Cetrimonio , Congelación , Cinética , Microscopía Electrónica , Modelos Moleculares , Fotones , Dodecil Sulfato de Sodio
15.
J Phys Chem B ; 110(26): 13005-10, 2006 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-16805607

RESUMEN

We report on the dynamics of a chromophore sequestered within the nonpolar regions of micelles and unilamellar vesicles comprised of decanoic acid/sodium decanoate. We find that there is a measurable difference in the motional dynamics of the chromophore perylene in these two nonpolar media, with the vesicle structure forming a somewhat less viscous environment than the micelle. In all cases, the chromophore reorients as a prolate rotor, implying a local environment with a nominally similar shape for both micelle and vesicle structures. These findings demonstrate that the organization of micelles is measurably different than that of bilayers.

16.
J Phys Chem A ; 110(10): 3426-31, 2006 Mar 16.
Artículo en Inglés | MEDLINE | ID: mdl-16526621

RESUMEN

We report on the fluorescence lifetime and rotational diffusion dynamics of 4-benzylamino-7-nitrobenzofurazan (BBD) in a series of 1-propanol/water binary solvent systems. The fluorescence lifetime of BBD increases monotonically with increasing 1-propanol concentration. The rotational diffusion dynamics of BBD also vary with solution 1-propanol content, but this variation is not monotonic. Comparison of the BBD rotational diffusion time constant to solution viscosity and 1-propanol composition reveals the presence of a solution composition dependence of solvent-solute interactions, with a relative decrease in solvent-solute interaction strength for solvent system compositions where the 1-propanol/water azeotrope is known to exist. These data point collectively to the existence of microscopic heterogeneity in these binary solvent systems.

17.
Infect Immun ; 73(12): 8039-49, 2005 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-16299298

RESUMEN

D-gluconate which is primarily catabolized via the Entner-Doudoroff (ED) pathway, has been implicated as being important for colonization of the streptomycin-treated mouse large intestine by Escherichia coli MG1655, a human commensal strain. In the present study, we report that an MG1655 Deltaedd mutant defective in the ED pathway grows poorly not only on gluconate as a sole carbon source but on a number of other sugars previously implicated as being important for colonization, including L-fucose, D-gluconate, D-glucuronate, N-acetyl-D-glucosamine, D-mannose, and D-ribose. Furthermore, we show that the mouse intestine selects mutants of MG1655 Deltaedd and wild-type MG1655 that have improved mouse intestine-colonizing ability and grow 15 to 30% faster on the aforementioned sugars. The mutants of MG1655 Deltaedd and wild-type MG1655 selected by the intestine are shown to be nonmotile and to have deletions in the flhDC operon, which encodes the master regulator of flagellar biosynthesis. Finally, we show that DeltaflhDC mutants of wild-type MG1655 and MG1655 Deltaedd constructed in the laboratory act identically to those selected by the intestine; i.e., they grow better than their respective parents on sugars as sole carbon sources and are better colonizers of the mouse intestine.


Asunto(s)
Metabolismo de los Hidratos de Carbono , Proteínas de Unión al ADN/genética , Proteínas de Escherichia coli/genética , Escherichia coli/crecimiento & desarrollo , Intestinos/microbiología , Transactivadores/genética , Animales , Metabolismo de los Hidratos de Carbono/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Eliminación de Gen , Genes Bacterianos , Gluconatos/metabolismo , Ratones
18.
Proc Natl Acad Sci U S A ; 101(19): 7427-32, 2004 May 11.
Artículo en Inglés | MEDLINE | ID: mdl-15123798

RESUMEN

Whole-genome expression profiling revealed Escherichia coli MG1655 genes induced by growth on mucus, conditions designed to mimic nutrient availability in the mammalian intestine. Most were nutritional genes corresponding to catabolic pathways for nutrients found in mucus. We knocked out several pathways and tested the relative fitness of the mutants for colonization of the mouse intestine in competition with their wild-type parent. We found that only mutations in sugar pathways affected colonization, not phospholipid and amino acid catabolism, not gluconeogenesis, not the tricarboxylic acid cycle, and not the pentose phosphate pathway. Gluconate appeared to be a major carbon source used by E. coli MG1655 to colonize, having an impact on both the initiation and maintenance stages. N-acetylglucosamine and N-acetylneuraminic acid appeared to be involved in initiation, but not maintenance. Glucuronate, mannose, fucose, and ribose appeared to be involved in maintenance, but not initiation. The in vitro order of preference for these seven sugars paralleled the relative impact of the corresponding metabolic lesions on colonization: gluconate > N-acetylglucosamine > N-acetylneuraminic acid = glucuronate > mannose > fucose > ribose. The results of this systematic analysis of nutrients used by E. coli MG1655 to colonize the mouse intestine are intriguing in light of the nutrient-niche hypothesis, which states that the ecological niches within the intestine are defined by nutrient availability. Because humans are presumably colonized with different commensal strains, differences in nutrient availability may provide an open niche for infecting E. coli pathogens in some individuals and a barrier to infection in others.


Asunto(s)
Carbono/metabolismo , Escherichia coli/metabolismo , Intestinos/microbiología , Animales , Escherichia coli/genética , Perfilación de la Expresión Génica , Ratones , Análisis de Secuencia por Matrices de Oligonucleótidos
19.
Infect Immun ; 72(3): 1666-76, 2004 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-14977974

RESUMEN

Escherichia coli EDL933, an O157:H7 strain, is known to colonize the streptomycin-treated CD-1 mouse intestine by growing in intestinal mucus (E. A. Wadolkowski, J. A. Burris, and A. D. O'Brien, Infect. Immun. 58:2438-2445, 1990), but what nutrients and metabolic pathways are employed during colonization has not been determined. In this study, when the wild-type EDL933 strain was fed to mice along with an EDL933 DeltappsA DeltapckA mutant, which is unable to utilize tricarboxylic acid cycle intermediates and gluconeogenic substrates for growth, both strains colonized the mouse intestine equally well. Therefore, EDL933 utilizes a glycolytic substrate(s) for both initial growth and maintenance when it is the only E. coli strain fed to the mice. However, in the presence of large numbers of MG1655, a K-12 strain, it is shown that EDL933 utilizes a glycolytic substrate(s) for initial growth in the mouse intestine but appears to utilize both glycolytic and gluconeogenic substrates in an attempt to maintain colonization. It is further shown that MG1655 predominantly utilizes glycolytic substrates for growth in the mouse intestine whether growing in the presence or absence of large numbers of EDL933. Data are presented showing that although small numbers of EDL933 grow to large numbers in the intestine in the presence of large numbers of MG1655 when both strains are fed to mice simultaneously, precolonization with MG1655 affords protection against subsequent colonization by EDL933. Moreover, in mice that are precolonized with EDL933, small numbers of MG1655 are able to grow rapidly in the intestine and EDL933 is eliminated. In situ hybridization experiments using E. coli-specific rRNA probes showed that while MG1655 is found only in mucus, EDL933 is found both in mucus and closely associated with intestinal epithelial cells. The data are discussed with respect to competition for nutrients and to the protection that some intestinal commensal E. coli strains might afford against infection by O157:H7 strains.


Asunto(s)
Escherichia coli O157/crecimiento & desarrollo , Escherichia coli O157/metabolismo , Escherichia coli/crecimiento & desarrollo , Escherichia coli/metabolismo , Mucosa Intestinal/microbiología , Animales , Secuencia de Bases , Ciego/microbiología , ADN Bacteriano/genética , Células Epiteliales/microbiología , Escherichia coli/genética , Infecciones por Escherichia coli/microbiología , Escherichia coli O157/genética , Genes Bacterianos , Gluconeogénesis/genética , Glucólisis/genética , Masculino , Ratones , Moco/microbiología , Mutación , Especificidad de la Especie
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