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1.
J Intellect Disabil Res ; 68(2): 181-192, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37984471

RESUMEN

BACKGROUND: Adolescents with disabilities have fewer opportunities to participate in community-based fitness programmes. The purpose of this study was to examine the impact of a school-based running programme at a local middle school in Lebanon, Pennsylvania, on fitness and quality of life (QoL) in children with physical and cognitive disabilities in a life-skills classroom. METHODS: Nineteen adolescents with diagnosed disabilities including intellectual disability (ID), autism spectrum disorder and Down syndrome were recruited from three life-skills classrooms to participate in a school-based running programme. The programme was designed to be implemented two times/week for 6 weeks by classroom teachers/aides. Physical therapy faculty and students developed the programme and assisted with implementation. Each session lasted 30 min, consisting of a warm-up and cooldown, relay races, games and timed runs. Pre- and post-test measures included physiological cost index (PCI) and Paediatric Quality of Life Inventory™ (PedsQL™). Pre- and post-test data were compared using Wilcoxon signed rank tests. Each week participants also completed a training log to reflect on the activity for the day. RESULTS: Participants demonstrated significant improvements in PCI (P = 0.028) and the PedsQL™ (P = 0.008) following the running programme. CONCLUSIONS: Results of this study suggest that participation in a 6-week school-based running programme may improve fitness and QoL in adolescents with disabilities.


Asunto(s)
Trastorno del Espectro Autista , Personas con Discapacidad , Humanos , Niño , Adolescente , Calidad de Vida , Ejercicio Físico , Instituciones Académicas , Aptitud Física
2.
Lett Appl Microbiol ; 64(2): 158-163, 2017 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-27914208

RESUMEN

Plant growth-promoting rhizobacteria (PGPR) are studied as complements/alternatives to chemical fertilizers used in agriculture. However, poor information exists on the potential of PGPR from undisturbed ecosystems. Here, we have evaluated the plant growth-promoting (PGP) effect of rhizobacterial consortia from undisturbed Chilean arid ecosystems (Consortium C1) and agro-ecosystems (Consortium C2) on plant biomass production. The PGP effects of C1 and C2 were assayed in wheat seedlings (Triticum aestivum L.) grown in pots under growth chamber conditions and in pots placed in an open greenhouse under natural conditions, using two different Chilean Andisols (Piedras Negras and Freire series) kept either at 30 or 60% of their maximum water holding capacity (MWHC). PGP effects depended on the soil type, MWHC and the growth conditions tested. Although both consortia showed PGB effects in artificial soils relative to controls in growth chambers, only C1 provoked a PGP effect at 60% MWHC in phosphorus-poor soil of the 'Piedras Negras' series. At natural conditions, however, only C1 exhibited statistically significant PGP effects at 30% MWHC in 'Piedras Negras', yet and most importantly allowed to maintain similar plant biomass as at 60% MWHC. Our results support possible applications of rhizobacterial consortia from arid ecosystems to improve wheat growth in Chilean Andisols under water shortage conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: Wheat seedling inoculated with rhizobacterial consortia obtained from an undisturbed Chilean arid ecosystem showed improved growth in phosphorus-poor and partly dry soil. Arid ecosystems should be considered in further studies as an alternative source of microbial inoculants for agro-ecosystems subjected to stressful conditions by low nutrients and/or adverse climate events.


Asunto(s)
Consorcios Microbianos , Fósforo/análisis , Rhizobium/metabolismo , Microbiología del Suelo , Triticum/crecimiento & desarrollo , Triticum/microbiología , Agricultura/métodos , Sequías , Ecosistema , Desarrollo de la Planta/fisiología , Plantones/crecimiento & desarrollo , Plantones/microbiología , Suelo/química
3.
Glob Chang Biol ; 21(2): 676-97, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25204435

RESUMEN

We present quantitative reconstructions of regional vegetation cover in north-western Europe, western Europe north of the Alps, and eastern Europe for five time windows in the Holocene [around 6k, 3k, 0.5k, 0.2k, and 0.05k calendar years before present (bp)] at a 1° × 1° spatial scale with the objective of producing vegetation descriptions suitable for climate modelling. The REVEALS model was applied on 636 pollen records from lakes and bogs to reconstruct the past cover of 25 plant taxa grouped into 10 plant-functional types and three land-cover types [evergreen trees, summer-green (deciduous) trees, and open land]. The model corrects for some of the biases in pollen percentages by using pollen productivity estimates and fall speeds of pollen, and by applying simple but robust models of pollen dispersal and deposition. The emerging patterns of tree migration and deforestation between 6k bp and modern time in the REVEALS estimates agree with our general understanding of the vegetation history of Europe based on pollen percentages. However, the degree of anthropogenic deforestation (i.e. cover of cultivated and grazing land) at 3k, 0.5k, and 0.2k bp is significantly higher than deduced from pollen percentages. This is also the case at 6k in some parts of Europe, in particular Britain and Ireland. Furthermore, the relationship between summer-green and evergreen trees, and between individual tree taxa, differs significantly when expressed as pollen percentages or as REVEALS estimates of tree cover. For instance, when Pinus is dominant over Picea as pollen percentages, Picea is dominant over Pinus as REVEALS estimates. These differences play a major role in the reconstruction of European landscapes and for the study of land cover-climate interactions, biodiversity and human resources.


Asunto(s)
Biodiversidad , Cambio Climático , Modelos Teóricos , Dispersión de las Plantas , Europa (Continente) , Polen
4.
Lett Appl Microbiol ; 48(6): 756-62, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19344356

RESUMEN

AIMS: To investigate the effect of a mixture of rhamnolipid R1 and R2 biosurfactants produced by a Pseudomonas aeruginosa strain on the toxicity of phenol and chlorophenols to Pseudomonas putida DOT-T1E. METHODS AND RESULTS: Toxicity was quantified by the effective concentration 50% (EC50), that is the concentration that causes a 50% inhibition of bacterial growth. The presence of 300 mg l(-1) rhamnolipids, that is at about twice their critical micelle concentration (CMC), increased the EC50 of phenol, 4-chlorophenol, 2,4-dichlorophenol and 2,4,5-trichlorophenol by about 12, 19, 32 and 40%, respectively, and consequently reduced the bioavailability and the freely dissolved concentration of the toxic phenolic compounds. The reduction was related to the phenols' octanol-water partition coefficients (K(ow)). CONCLUSIONS: The reduction in toxicity of the phenols can be explained by a combination of toxin accumulation in biosurfactant micelles and hydrophobic interactions of the phenols with rhamnolipid-based dissolved organic carbon. SIGNIFICANCE AND IMPACT OF THE STUDY: Results provide evidence that next to the effect of the micelle formation also hydrophobic interactions with rhamnolipid-based dissolved organic carbon affects the bioavailability of the phenols. Quantifying the effect of biosurfactants on the toxicity of hydrophobic compounds such as phenols thus appears to be a useful approach to assess their bioavailable equilibrium concentration.


Asunto(s)
Clorofenoles/toxicidad , Glucolípidos/farmacología , Pseudomonas putida/efectos de los fármacos , Tensoactivos/farmacología , Glucolípidos/metabolismo , Pseudomonas aeruginosa/química , Pseudomonas aeruginosa/metabolismo , Tensoactivos/metabolismo
5.
East Mediterr Health J ; 15(4): 868-79, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-20187538

RESUMEN

This study investigated the rising rate of caesarean section (CS) deliveries between 1993 and 2002 (9.4% to 14.4%) and associated factors, including indications for CS and sociodemographic and clinical characteristics based on the register of a major Palestinian teaching hospital. Instrumental deliveries declined from 12.6% to 4.4%. Fetal distress decreased as an indication for CS, while previous CS and breech presentations contributed to the increase. Decision-making for CS needs to frame the benefits and risks of the intervention within the context of women's entire reproductive life-cycle and existing standards of care, avoiding unnecessary and costly CS deliveries to reduce iatrogenic complications and conserve resources.


Asunto(s)
Cesárea/tendencias , Hospitales de Enseñanza , Selección de Paciente , Pautas de la Práctica en Medicina/tendencias , Adolescente , Adulto , Presentación de Nalgas/cirugía , Distribución de Chi-Cuadrado , Femenino , Sufrimiento Fetal/cirugía , Investigación sobre Servicios de Salud , Humanos , Hipertensión Inducida en el Embarazo/cirugía , Modelos Logísticos , Auditoría Médica , Medio Oriente , Paridad , Embarazo , Factores Socioeconómicos , Procedimientos Innecesarios/tendencias
6.
(East. Mediterr. health j).
en Inglés | WHO IRIS | ID: who-117709

RESUMEN

This study investigated the rising rate of caesarean section [CS] deliveries between 1993 and 2002 [9.4% to 14.4%] and associated factors, including indications for CS and sociodemographic and clinical characteristics based on the register of a major Palestinian teaching hospital. Instrumental deliveries declined from 12.6% to 4.4%. Fetal distress decreased as an indication for CS, while previous CS and breech presentations contributed to the increase. Decision-making for CS needs to frame the benefits and risks of the intervention within the context of women's entire reproductive life-cycle and existing standards of care, avoiding unnecessary and costly CS deliveries to reduce iatrogenic complications and conserve resources


Asunto(s)
Cesárea Repetida , Sufrimiento Fetal , Presentación de Nalgas , Cesárea
7.
Appl Microbiol Biotechnol ; 80(3): 507-15, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18607588

RESUMEN

Despite growing interest in the electro-bioremediation of contaminated soil it is still largely unknown to which degree weak electric fields influence the fate of contaminant-degrading microorganisms in the sub-surface. Here we evaluate the factors influencing the electrokinetic transport and deposition of fluorene-degrading Sphingomonas sp. LB126 in a laboratory model aquifer exposed to a direct current (DC) electric field (1 V cm(-1)) typically used in electro-bioremediation measures. The influence of cell size, cell membrane integrity, cell chromosome contents (all assessed by flow cytometry), cell surface charge and cell hydrophobicity on the spatial distribution of the suspended and matrix-bound cells after 15 h of DC-treatment was evaluated. In presence of DC the cells were predominantly mobilised by electroosmosis to the cathode with an apparent velocity of 0.6 cm h(-1), whereas a minor fraction only of the cells augmented was mobilised to the anode by electrophoresis. Different electrokinetic behaviour of individual cells could be solely attributed to intra-population heterogeneity of the cell surface charge. In the absence of DC by contrast, a Gaussian-type distribution of bacteria around the point of injection was found. DC had no influence on the deposition efficiency, as the glass beads in presence and absence of an electric field retained quasi-equal fractions of the cells. Propidium iodide staining and flow cytometry analysis of the cells indicated the absence of negative influences of DC on the cell wall integrity of electrokinetically mobilised cells and thus point at unchanged physiological fitness of electrokinetically mobilised bacteria.


Asunto(s)
Modelos Biológicos , Hidrocarburos Policíclicos Aromáticos/metabolismo , Sphingomonas/citología , Sphingomonas/fisiología , Biodegradación Ambiental , Electrofisiología , Cinética
8.
J Obstet Gynaecol ; 27(4): 368-73, 2007 May.
Artículo en Inglés | MEDLINE | ID: mdl-17654188

RESUMEN

This randomised controlled trial of routine amniotomy was carried out in a developing country setting to investigate the effect of this common procedure on the duration of labour, intra-partum interventions and selected newborn and maternal outcomes. In a Jerusalem teaching hospital, 533 multiparous and 157 nulliparous low-risk women were randomised to either amniotomy or intent to conserve membranes. For multiparae, the median duration from randomisation to full dilatation was 95 and 160 min, respectively in the intervention and control arms (p < 0.001); for nulliparae it was 210 and 270 min, respectively (p < 0.001). In both groups, oxytocin was used less in the intervention arms (p < 0.001), and no difference in mode of delivery and immediate outcomes was detected. However, given the risks of this intervention and these study findings indicating an overall short duration of childbirth, amniotomy should be limited to cases of abnormal progress of labour.


Asunto(s)
Amnios/cirugía , Países en Desarrollo , Trabajo de Parto Inducido/métodos , Adulto , Femenino , Humanos , Israel , Embarazo , Resultado del Embarazo , Factores de Tiempo
9.
Eur Radiol ; 15(9): 1867-75, 2005 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-15856244

RESUMEN

The purpose of our study was to evaluate magnetic resonance (MR) signal characteristics of acutely forming heterotopic ossification (HO) in paralyzed patients. Fourteen patients with spinal cord injury (female n=2, male n=12, mean age 38.3 years) and acute onset of radiographically proven HO had contrast-enhanced 1.5-T MRI within 13.4+/-18.3 days of clinical onset of symptoms. MR signal alterations of affected muscles, fascia, subcutaneous tissue, skin and adjacent bone were evaluated. A diffuse T2-hyperintense signal of multiple muscle groups was seen in all patients (bilateral in 12) involving quadriceps (n=13, 93%), adductors (n=13, 93%) and iliopsoas (n=12, 86%) with contrast enhancement in n=11 (79%), n=8 (57%) and n=8 (57%) patients. All patients had nonenhancing areas (mean size 2 x 3.5 x 5.8 cm) within diffusely enhancing muscles. HO formation occurred around these nonenhancing areas in four patients with computed tomography follow-up. Other MR findings included fascial edema (n=14, 100%), fascial enhancement (n=13, 93%), subcutaneous edema (n=13, 93%), subcutaneous enhancement (n=12, 86%), bone marrow edema (n=5, 36%), and joint effusion (n=12, 86%). MRI reveals mostly bilateral edema and enhancement of muscles, fascia and subcutaneous tissue during acute onset of HO. HO develops in the periphery of well-defined areas of no enhancement.


Asunto(s)
Imagen por Resonancia Magnética , Osificación Heterotópica/diagnóstico , Traumatismos de la Médula Espinal/complicaciones , Adolescente , Adulto , Anciano , Enfermedades de la Médula Ósea/diagnóstico , Medios de Contraste , Edema/diagnóstico , Fascia/patología , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Enfermedades Musculares/diagnóstico , Enfermedades Musculoesqueléticas/diagnóstico , Paraplejía/complicaciones , Músculos Psoas/patología , Cuadriplejía/complicaciones , Enfermedades de la Piel/diagnóstico , Líquido Sinovial , Muslo/patología , Tomografía Computarizada por Rayos X
10.
Int J Gynaecol Obstet ; 89(2): 174-8, 2005 May.
Artículo en Inglés | MEDLINE | ID: mdl-15847891

RESUMEN

OBJECTIVE: This study describes staffing, caseloads and reported routine practices for normal childbirth in Palestinian West Bank (WB) governmental maternity facilities and compares these practices with evidence-based care. METHODS: Data on routine childbirth practices in all eight governmental hospitals were obtained through interviews with head obstetricians and midwives. Data on staffing and monthly number of births were collected by phone or personal interview from all 37 WB hospitals. RESULTS: Forty-eight percent of WB deliveries took place in crowded and understaffed governmental hospitals. Reported practices were not consistently in line with evidence-based care. Lack of knowledge and structural barriers were reasons for this gap. CONCLUSION: The implications of limiting unnecessary interventions in the normal birth process are particularly important in a context of limited access and scarce resources. More skilled birth attendants and a universal commitment to effective care are needed.


Asunto(s)
Parto Obstétrico/estadística & datos numéricos , Maternidades/organización & administración , Hospitales Públicos/organización & administración , Analgésicos Opioides/uso terapéutico , Actitud del Personal de Salud , Competencia Clínica , Aglomeración , Parto Obstétrico/economía , Utilización de Medicamentos/estadística & datos numéricos , Medicina Basada en la Evidencia , Femenino , Adhesión a Directriz , Maternidades/estadística & datos numéricos , Hospitales Públicos/estadística & datos numéricos , Humanos , Masculino , Meperidina/uso terapéutico , Medio Oriente , Partería/estadística & datos numéricos , Oxitócicos/uso terapéutico , Oxitocina/uso terapéutico , Admisión y Programación de Personal , Médicos/provisión & distribución , Embarazo , Sector Privado/estadística & datos numéricos , Encuestas y Cuestionarios , Carga de Trabajo
11.
Bone ; 34(5): 869-80, 2004 May.
Artículo en Inglés | MEDLINE | ID: mdl-15121019

RESUMEN

The aim of the present study was to describe bone loss of the separate compartments of trabecular and cortical bone, as well as changes in bone geometry of a large number of spinal cord injured (SCI) individuals. Eighty-nine motor complete spinal cord injured men (24 tetraplegics and 65 paraplegics) with a duration of paralysis of between 2 months and 50 years were included in the study. Distal epiphyses and midshafts of the femur, tibia, and radius were measured by peripheral quantitative computed tomography. The same measurements were performed in a reference group of 21 healthy able-bodied men of the same age range. In the femur and tibia, bone mass, total and trabecular bone mineral density (BMDtot and BMDtrab, respectively) of the epiphyses, as well as bone mass and cortical cross-sectional area of the diaphyses, showed an exponential decrease with time after injury in the spinal cord injured subjects. The decreasing bone parameters reached new steady states after 3-8 years, depending on the parameter. Bone mass loss in the epiphyses was approximately 50% in the femur and 60% in the tibia, while the shafts lost only approximately 35% in the femur and 25% in the tibia. In the epiphyses, bone mass was lost by reducing BMD, while in the shaft bone mass was lost by reducing cortical wall thickness, a process achieved by endosteal resorption advancing at a rate of about 0.25 mm/year within the first 5-7 years after injury. Except for a slight transient decrease in cortical BMD of the femoral and tibial shaft during the first 5 years after the spinal cord lesion, cortical BMD of the spinal cord injured subjects was found to be at reference values. Bone parameters of the radial epiphysis in paraplegic subjects showed no deficits compared to the reference group. Furthermore, a trend for an increased radial shaft diameter suggests periosteal apposition as a consequence of increased loading of the arms.


Asunto(s)
Huesos/anatomía & histología , Parálisis/fisiopatología , Traumatismos de la Médula Espinal/fisiopatología , Adulto , Densidad Ósea , Huesos/fisiopatología , Humanos , Reproducibilidad de los Resultados
12.
Spinal Cord ; 41(3): 192-8, 2003 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-12612623

RESUMEN

STUDY DESIGN: Retrospective review of patient data. OBJECTIVES: (i) To determine the incidence and time of deep vein thrombosis (DVT) under low molecular weight heparin (LMWH) prophylaxis in spinal cord injury (SCI), (ii) to determine the incidence and time of heterotopic ossification (HO) and (iii) to assess a possible aetiologic relationship in the pathogenesis of DVT and HO. SETTING: Swiss Paraplegic Centre, Nottwil. METHODS: We analyzed the incidence of DVT and HO in 1209 SCI patients (275 first rehabilitations) at the Swiss Paraplegic Centre Nottwil from 1998 to 2000. Clinical files and laboratory data were scrutinised for particularities preceding DVT and HO. RESULTS: The incidence of DVT was 6.55% for first rehabilitation compared to only 1.59% in all patients hospitalised. DVT was complicated by pulmonary embolism (PE) in 1.45% and 0.47% respectively. Incidence of HO was 8% for first rehabilitation and 1.82% for all patients hospitalised. In first rehabilitation patients the peak for DVT occurred around day 30 contrary to HO with a peak around day 120. In single patients HO was identified by MRI as a rapidly progressing process. Laboratory profiles were inflammatory in both HO and DVT. Increased physical activity preceding HO was observed in four patients. In two patients acute HO was complicated by ipsilateral DVT. CONCLUSION: Prophylaxis with LMWH and elastic stockings significantly reduces the frequency of DVT during first rehabilitation in SCI. DVT and HO are both associated with laboratory parameters of non-infectious inflammation. The later onset of HO coinciding with ongoing mobilisation, argues for a different pathogenetic mechanism. Acute HO of the hip region appears to favour ipsilateral DVT by well known thrombogenic mechanisms.


Asunto(s)
Osificación Heterotópica/epidemiología , Centros de Rehabilitación/estadística & datos numéricos , Traumatismos de la Médula Espinal/epidemiología , Trombosis de la Vena/epidemiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Distribución de Chi-Cuadrado , Niño , Preescolar , Femenino , Humanos , Masculino , Persona de Mediana Edad , Osificación Heterotópica/diagnóstico , Osificación Heterotópica/etiología , Osificación Heterotópica/rehabilitación , Traumatismos de la Médula Espinal/complicaciones , Traumatismos de la Médula Espinal/diagnóstico , Traumatismos de la Médula Espinal/rehabilitación , Suiza/epidemiología , Trombosis de la Vena/diagnóstico , Trombosis de la Vena/etiología , Trombosis de la Vena/rehabilitación
13.
Chemosphere ; 49(8): 845-63, 2002 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-12430662

RESUMEN

Fire regimes have changed during the Holocene due to changes in climate, vegetation, and in human practices. Here, we hypothesise that changes in fire regime may have affected the global CO2 concentration in the atmosphere through the Holocene. Our data are based on quantitative reconstructions of biomass burning deduced from stratified charcoal records from Europe, and South-, Central- and North America, and Oceania to test the fire-carbon release hypothesis. In Europe the significant increase of fire activity is dated approximately 6000 cal. yr ago. In north-eastern North America burning activity was greatest before 7500 years ago, very low between 7500-3000 years, and has been increasing since 3000 years ago. In tropical America, the pattern is more complex and apparently latitudinally zonal. Maximum burning occurred in the southern Amazon basin and in Central America during the middle Holocene, and during the last 2000 years in the northern Amazon basin. In Oceania, biomass burning has decreased since a maximum 5000 years ago. Biomass burning has broadly increased in the Northern and Southern hemispheres throughout the second half of the Holocene associated with changes in climate and human practices. Global fire indices parallel the increase of atmospheric CO2 concentration recorded in Antarctic ice cores. Future issues on carbon dynamics relatively to biomass burning are discussed to improve the quantitative reconstructions.


Asunto(s)
Carbono/química , Carbón Orgánico/química , Evolución Planetaria , Suelo/análisis , Américas , Asia Sudoriental , Biomasa , Dióxido de Carbono/química , Europa (Continente) , Incendios
14.
Appl Microbiol Biotechnol ; 58(3): 378-85, 2002 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11935191

RESUMEN

Several recent reports have indicated that some bacteria may have adapted to the low bioavailability of hydrophobic environmental chemicals and that generalizations about the bioavailability of compounds such as polycyclic aromatic hydrocarbons (PAHs) may be inappropriate. Experimental evidence and theoretical considerations show that the utilization of PAHs requires bioavailability-enhancing mechanisms of the bacteria such as: (1) high-affinity uptake systems, (2) adhesion to the solid substrate, and (3) biosurfactant excretion. We examined possible specific physiological responses of anthracene-degrading Mycobacterium sp. LB501T to poorly water-soluble anthracene in batch cultures, using solid anthracene as a sole carbon source. Mycobacterium sp. LB501T exhibited a high specific affinity for anthracene (a(o)A=32,500 l g(-1) protein h(-1)) and grew as a confluent biofilm on solid anthracene present as sole carbon source. No biofilm formation on anthracene was observed when excess glucose was provided as an additional substrate. This difference could be attributed to a modification of the cell surface of the bacterium. Anthracene-grown cells were significantly more hydrophobic and more negatively charged than glucose-grown cells. In adhesion experiments, anthracene-grown cells adhered 1.5- to 8.0-fold better to hydrophobic Teflon and up to 70-fold better to anthracene surfaces than glucose-grown cells. However, no production of biosurfactants was observed. Our results thus indicate that attachment and biofilm formation may be a specific response of Mycobacterium sp. LB501T to optimize substrate bioavailability.


Asunto(s)
Antracenos/farmacología , Mycobacterium/crecimiento & desarrollo , Mycobacterium/metabolismo , Antracenos/química , Disponibilidad Biológica , Biomasa , Relación Dosis-Respuesta a Droga , Microscopía Electrónica de Rastreo , Mycobacterium/efectos de los fármacos , Mycobacterium/ultraestructura , Microbiología del Suelo , Factores de Tiempo
15.
Environ Microbiol ; 3(9): 588-99, 2001 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-11683869

RESUMEN

To investigate the ability of Escherichia coli K12 MG1655 to cope with excess and limitation of a carbon and energy source, we studied the changes in kinetic properties and two-dimensional (2D) gel protein patterns of an E. coli culture. The population was transferred from glucose-excess batch to glucose-limited continuous culture (D = 0.3 h(-1)), in which it was cultivated for 500 h (217 generations) and then transferred back to glucose-excess batch culture. Two different stages to glucose-limitation were recognized: a short-term physiological adaptation characterized by a general effort in enhancing the cell's substrate scavenging ability and mutations resulting in a population exhibiting increased glucose affinity. Physiological short-term adaptation to glucose-limitation was achieved by upregulation of 12 proteins, namely MglB, MalE, ArgT, DppA, RbsB, YdcS, LivJ (precursor), UgpB (precursor), AceA, AldA, AtpA and GatY. Eight of these proteins are periplasmic binding proteins of ABC transporters. Most of them are not involved in glucose transport regulons, but rather in chemotaxis and transport of other substrates, whereas MalE and MglB have previously been shown to belong to transport systems important in glucose transport under glucose-limited conditions. Evolution under low glucose concentration led to an up to 10-fold increase in glucose affinity (from a K(s) of 366 +/- 36 microg l(-1) at the beginning to 44 +/- 7 microg l(-1)). The protein pattern of a "500-h-old" continuous culture showed a highly increased expression of MglB and MalE as well as of the regulator protein MalI. When adapted cells taken from the "500-h-old" continuous culture were transferred to batch culture, an increased expression of MalE was observed, compared with cells from un-adapted batch-grown cells. Otherwise, no significant changes were observed in the protein pattern of batch-grown populations before and after 500 h of evolution in the glucose-limited continuous culture.


Asunto(s)
Escherichia coli/metabolismo , Glucosa/metabolismo , Proteoma/metabolismo , Evolución Biológica , Transporte Biológico , Escherichia coli/enzimología , Escherichia coli/crecimiento & desarrollo , Cinética , Mutación , Consumo de Oxígeno , Fosfotransferasas/metabolismo
16.
Environ Sci Technol ; 35(10): 2033-9, 2001 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-11393985

RESUMEN

The effect of the nonionic surfactant Brij 35 on the bioavailability of solid and Teflon-sorbed dibenzofuran for Sphingomonas sp. strain HH19k was studied in simple model systems. Growth with dibenzofuran and dibenzofuran-specific oxygen uptake in surfactant-free media and with Brij 35 above the critical micelle concentration (cmc) were compared with dissolution and desorption in the absence of bacteria. Brij 35 accelerated dissolution and biodegradation of solid dibenzofuran by a factor of 2. It also enhanced the initial desorption rate of dibenzofuran from Teflon by this factor. Continuously decreasing desorption rates were attributed to slow diffusion of dibenzofuran inside Teflon, leading to depletion of dibenzofuran in the exterior of the Teflon particles. Surprisingly, Brij 35 slowed the initial biodegradation of desorbing dibenzofuran. We propose two processes that led to low bioavailability of sorbed dibenzofuran in the presence of surfactant. First, desorbing dibenzofuran rapidly accumulated in surfactant micelles, leading to reduced truly water-dissolved dibenzofuran concentration as the factor controlling the biodegradation rate. Second, Brij 35 suppressed the contact between bacteria and Teflon. This increased the average diffusion distance of dibenzofuran to the bacteria, which in turn flattened the gradient of the dissolved dibenzofuran concentration between the sorbent and the cells as the driving force for desorption.


Asunto(s)
Benzofuranos/farmacocinética , Detergentes/química , Polietilenglicoles/química , Sphingomonas/fisiología , Contaminantes Químicos del Agua/farmacocinética , Benzofuranos/metabolismo , Biodegradación Ambiental , Disponibilidad Biológica , Difusión , Polidocanol , Solubilidad , Distribución Tisular , Contaminantes Químicos del Agua/metabolismo
17.
Environ Sci Technol ; 35(2): 354-61, 2001 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-11347609

RESUMEN

The importance of mass transfer relative to the intrinsic microbial activity was examined in a laboratory system using Mycobacterium sp. LB501T and poorly soluble anthracene as sole carbon source. M. sp. LB501T was grown on various amounts of solid anthracene in batch cultures, and microbial biomass formation was compared to independently determined dissolution fluxes. Provision of only a few anthracene crystals (< or = 2 g L(-1)) resulted in pseudolinear growth due to low dissolution fluxes, whereas exponential growth was only obtained when high amounts of solid anthracene (30 g L(-1)) were provided. The influence of substrate bioavailability on microbial growth was predicted successfully by a dynamic, flux-based approach (Best-Equation), which combines substrate dissolution from crystals into solution, substrate uptake by microorganisms from solution, and concurrent biomass formation.


Asunto(s)
Antracenos/química , Mycobacterium/crecimiento & desarrollo , Cinética , Microscopía Electrónica de Rastreo , Mycobacterium/ultraestructura
18.
Skeletal Radiol ; 29(3): 162-4, 2000 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10794553

RESUMEN

The retroisthmic cleft is a rarely diagnosed defect in the lamina of the lumbar spine. It has always been considered a congenital anomaly. This is the first report we are aware of showing radiological changes in a retroisthmic cleft over a period of time. The follow-up of this patient over a period of 6 years, the radiological and scintigraphic appearances and a review of the literature suggests that the retroisthmic cleft is a stress fracture of the lamina.


Asunto(s)
Fracturas por Estrés/diagnóstico por imagen , Fracturas por Estrés/diagnóstico , Vértebras Lumbares/diagnóstico por imagen , Vértebras Lumbares/lesiones , Fracturas de la Columna Vertebral/diagnóstico por imagen , Fracturas de la Columna Vertebral/diagnóstico , Adulto , Humanos , Imagen por Resonancia Magnética , Masculino , Radiografía , Tomografía Computarizada de Emisión de Fotón Único
19.
Environ Health Perspect ; 106 Suppl 4: 1069-74, 1998 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-9703495

RESUMEN

Benzene, diphenyl sulfone (DPS), para-hydroxybiphenyl (PPP), ortho-hydroxybiphenyl (OPP), higher hydroxybiphenyls, and alkylated benzenes were found in a small lake receiving contaminated groundwater discharge from the Industri-Plex Superfund site (Woburn, MA) in the Aberjona watershed in eastern Massachusetts. All of these chemicals may derive from the former phenol manufacturing activities present at the Industri-Plex site during World War I. Concentrations up to 1660 microgram/l benzene, 450 micro/l DPS, 230 microgram/l PPP, and 100 microgram/l OPP were detected in the hypolimnion. Epilimnetic concentrations of the chemicals were significantly lower (normally < 5 microgram/l). DPS showed a distinct seasonal behavior: It was readily biodegradable during warm periods. No biodegradation was observed in the winter, leaving export to the Aberjona River as the major removal mechanism. Although benzene is known to be toxic and a human carcinogen, our results indicate that DPS, OPP, and PPP are not mutagenic in tests using human MCL-5 and h1A1v2 cell lines.


Asunto(s)
Derivados del Benceno/análisis , Monitoreo del Ambiente , Residuos Peligrosos , Contaminantes Químicos del Agua/análisis , Derivados del Benceno/efectos adversos , Línea Celular , Humanos , Industrias , Pruebas de Mutagenicidad , Fenoles , Contaminantes Químicos del Agua/efectos adversos
20.
Transplant Proc ; 27(4): 2539-44, 1995 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-7652921

RESUMEN

OBJECTIVES: To examine the national Pediatric Intensive Care Unit (PICU) experience regarding Medical Examiner (ME) refusal of organ procurement from potential donors. To review our experience regarding PICU mortalities, organ donation, and impact of the ME on the organ donation process. DESIGN: National survey of PICU directors requesting demographics, type of ME system, perceptions of ME responsiveness to organ donation, and data regarding potential donors and their outcomes. Also, a retrospective chart review of all PICU deaths from 1990 to 1992 at a tertiary care center, noting the number of potential organ donors, ME cases, those harvested, rejected, and reason for rejection. PARTICIPANTS: PICU directors selected from a list of Pediatric Section members of the Society of Critical Care Medicine. The response rate was 59%. The chart review was performed in a 1000-bed hospital with a 12-bed PICU. RESULTS: PICU directors' perceptions of ME responsiveness to organ donation were not determined by size of PICU, area served, type of hospital, ME system, or means of contacting the ME. ME refusal accounted for 15% and 16% of total refusals in the survey and chart review, respectively. Family refusal accounted for 49% and 28% in these same groups. Survey respondents' hints and suggestions to decrease denial and increase organ donation focused on improved communication (61% and 33%), and education (16% and 55%). CONCLUSIONS: ME refusal does impact on pediatric organ donation, but not as significantly as family refusal. Increased organ procurement in ME-related cases will require improved communication between MEs, physicians, and the Organ Procurement Organizations (OPOs).


Asunto(s)
Médicos Forenses , Pediatría , Donantes de Tejidos , Obtención de Tejidos y Órganos/organización & administración , Actitud del Personal de Salud , Niño , Demografía , Familia , Humanos , Estudios Retrospectivos , Encuestas y Cuestionarios , Virginia
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