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1.
Sci Total Environ ; 835: 155398, 2022 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-35469882

RESUMEN

The fate of plastics in rivers is a key component of the global plastic cycle. Plastics entering freshwater ecosystems are colonized by microbial biofilms, and microbe-plastic interactions can influence ecosystem processes and plastic fate. While literature examining the role of geographic region on plastic biofilms is quickly expanding, research which covers large (i.e., continental) spatial scales and includes freshwater ecosystems is warranted. In addition, most research focuses on bacterial communities, while biofilm eukaryotes are less commonly studied. We assessed biofilm metabolism and community structure on plastic (foamed polystyrene and polyvinyl chloride; PVC) and natural substrates (unglazed ceramic tile) in urban streams spanning a nested geographic gradient in the continental United States. We measured biofilm biomass, community respiration, and chlorophyll a, in addition to assessing marker gene-based community diversity of bacterial, fungal, and algal assemblages. Results demonstrated some substrate-specific trends in biofilm characteristics, including higher biofilm biomass on polystyrene across sites, and lower diversity of bacterial assemblages on both types of plastic litter versus tile. However, there were no differences among substrates for chlorophyll, respiration, and the abundance and diversity of algal and fungal assemblages. Thus, we concluded that the primary driver of biofilm metabolism and community composition were site characteristics, rather than substrate type. Additional studies are needed to quantify which site-specific characteristics drive biofilm dynamics on plastic litter in streams (e.g., water chemistry, light, seasonality, hydrology). These results add to the growing literature on the biofilm 'plastisphere' in aquatic ecosystems, demonstrating that the factors which control the assembly and activity of biofilm communities on plastic substrates (including bacteria, algal, and fungal assemblages together) in urban streams are similar to those driving biofilm dynamics on natural substrates.


Asunto(s)
Plásticos , Ríos , Bacterias , Biopelículas , Clorofila A , Ecosistema , Poliestirenos
2.
J Mol Med (Berl) ; 97(5): 723-736, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-30918989

RESUMEN

Pannexins (Panxs), large-pore channel forming glycoproteins, are expressed in a wide variety of tissues including the skin, bone, and cochlea. To date, the use of single knock-out mouse models of both Panx1 and Panx3 have demonstrated their roles in skin development, bone formation, and auditory phenotypes. Due to sequence homology between Panx1 and Panx3, when one Panx is ablated from germline, the other may be upregulated in a compensatory mechanism to maintain tissue homeostasis and function. To evaluate the roles of Panx1 and Panx3 in the skin, bone, and cochlea, we created the first Panx1/Panx3 double knock-out mouse model (dKO). These mice had smaller litters and reduced body weight compared to wildtype controls. The dKO dorsal skin had decreased epidermal and dermal area as well as decreased hypodermal area in neonatal but not in older mice. In addition, mouse skull shape and size were altered, and long bone length was decreased in neonatal dKO mice. Finally, auditory tests revealed that dKO mice did not exhibit hearing loss and were even slightly protected against noise-induced hearing damage at mid-frequency regions. Taken together, our findings suggest that Panx1 and Panx3 are important at early stages of development in the skin and bone but may be redundant in the auditory system. KEY MESSAGES: Panx double KO mice had smaller litters and reduced body weight. dKO skin had decreased epidermal and dermal area in neonatal mice. Skull shape and size changed plus long bone length decreased in neonatal dKO mice. dKO had no hearing loss and were slightly protected against noise-induced damage.


Asunto(s)
Desarrollo Óseo , Cóclea/crecimiento & desarrollo , Conexinas/genética , Eliminación de Gen , Proteínas del Tejido Nervioso/genética , Piel/crecimiento & desarrollo , Animales , Huesos/metabolismo , Cóclea/metabolismo , Audición , Ratones Endogámicos C57BL , Ratones Noqueados , Piel/metabolismo
3.
Sci Rep ; 8(1): 11639, 2018 08 03.
Artículo en Inglés | MEDLINE | ID: mdl-30076314

RESUMEN

Microplastic is a contaminant of concern worldwide. Rivers are implicated as major pathways of microplastic transport to marine and lake ecosystems, and microplastic ingestion by freshwater biota is a risk associated with microplastic contamination, but there is little research on microplastic ecology within freshwater ecosystems. Microplastic uptake by fish is likely affected by environmental microplastic abundance and aspects of fish ecology, but these relationships have rarely been addressed. We measured the abundance and composition of microplastic in fish and surface waters from 3 major tributaries of Lake Michigan, USA. Microplastic was detected in fish and surface waters from all 3 sites, but there was no correlation between microplastic concentrations in fish and surface waters. Rather, there was a significant effect of functional feeding group on microplastic concentration in fish. Neogobius melanostomus (round goby, a zoobenthivore) had the highest concentration of gut microplastic (19 particles fish-1) compared to 10 other fish taxa measured, and had a positive linear relationship between body size and number of microplastic particles. Surface water microplastic concentrations were lowest in the most northern, forested watershed, and highest in the most southern, agriculturally dominated watershed. Results suggest microplastic pollution is common in river food webs and is connected to species feeding characteristics. Future research should focus on understanding the movement of microplastic from point-source and diffuse sources and into aquatic ecosystems, which will support pollution management efforts on inland waters.


Asunto(s)
Ecosistema , Peces/fisiología , Plásticos/efectos adversos , Contaminantes Químicos del Agua/toxicidad , Animales , Monitoreo del Ambiente , Agua Dulce/química , Humanos , Lagos/química , Ríos/química
4.
J Gastrointest Surg ; 21(4): 614-621, 2017 04.
Artículo en Inglés | MEDLINE | ID: mdl-28120276

RESUMEN

BACKGROUND: Enhanced recovery programmes improve outcomes in surgery, but their implementation after upper gastrointestinal resection has been limited. The aim of this study was to compare short-term outcomes for patients undergoing oesophagogastric surgery in an enhanced recovery programme (EROS). METHODS: EROS was developed after a multidisciplinary meeting by multiple rounds of revision. EROS was applied to all patients undergoing major upper GI resection at a university teaching hospital in the UK from 20/9/13, with data reviewed at 18/09/15. EROS was assessed to identify predictors for compliance. RESULTS: One hundred six patients underwent major upper GI resection including 81 oesophagectomies, 24 gastrectomies and 1 colonic interposition graft. Major complications (Clavien Dindo ≥3) occurred in 12 patients with 1 in-hospital death. Thirty-five patients (44%) were discharged on target day 8 of the EROS programme. Age and complications were independently associated with missing this discharge target. CONCLUSION: Enhanced recovery is feasible and safe after major upper gastrointestinal surgery.


Asunto(s)
Esofagectomía , Gastrectomía , Atención Perioperativa/métodos , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Colon/trasplante , Ambulación Precoz , Esofagectomía/efectos adversos , Femenino , Gastrectomía/efectos adversos , Humanos , Tiempo de Internación , Masculino , Persona de Mediana Edad , Alta del Paciente , Desarrollo de Programa , Resultado del Tratamiento
5.
BMC Cancer ; 16(1): 710, 2016 09 02.
Artículo en Inglés | MEDLINE | ID: mdl-27589870

RESUMEN

BACKGROUND: In 2014 approximately 21,200 patients were diagnosed with oesophageal and gastric cancer in England and Wales, of whom 37 % underwent planned curative treatments. Potentially curative surgical resection is associated with significant morbidity and mortality. For operable locally advanced disease, neoadjuvant chemotherapy (NAC) improves survival over surgery alone. However, NAC carries the risk of toxicity and is associated with a decrease in physical fitness, which may in turn influence subsequent clinical outcome. Lower levels of physical fitness are associated with worse outcome following major surgery in general and Upper Gastrointestinal Surgery (UGI) surgery in particular. Cardiopulmonary exercise testing (CPET) provides an objective assessment of physical fitness. The aim of this study is to test the hypothesis that NAC prior to upper gastrointestinal cancer surgery is associated with a decrease in physical fitness and that the magnitude of the change in physical fitness will predict mortality 1 year following surgery. METHODS: This study is a multi-centre, prospective, blinded, observational cohort study of participants with oesophageal and gastric cancer scheduled for neoadjuvant cancer treatment (chemo- and chemoradiotherapy) and surgery. The primary endpoints are physical fitness (oxygen uptake at lactate threshold measured using CPET) and 1-year mortality following surgery; secondary endpoints include post-operative morbidity (Post-Operative Morbidity Survey (POMS)) 5 days after surgery and patient related quality of life (EQ-5D-5 L). DISCUSSION: The principal benefits of this study, if the underlying hypothesis is correct, will be to facilitate better selection of treatments (e.g. NAC, Surgery) in patients with oesophageal or gastric cancer. It may also be possible to develop new treatments to reduce the effects of neoadjuvant cancer treatment on physical fitness. These results will contribute to the design of a large, multi-centre trial to determine whether an in-hospital exercise-training programme that increases physical fitness leads to improved overall survival. TRIAL REGISTRATION: ClinicalTrials.gov NCT01325883 - 29(th) March 2011.


Asunto(s)
Quimioradioterapia Adyuvante/métodos , Quimioterapia Adyuvante/métodos , Procedimientos Quirúrgicos del Sistema Digestivo/mortalidad , Neoplasias Gastrointestinales/terapia , Aptitud Física/fisiología , Inglaterra , Prueba de Esfuerzo/métodos , Femenino , Neoplasias Gastrointestinales/mortalidad , Neoplasias Gastrointestinales/fisiopatología , Humanos , Masculino , Estudios Prospectivos , Calidad de Vida , Análisis de Supervivencia , Resultado del Tratamiento , Gales
6.
J Hum Hypertens ; 29(12): 737-43, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25810066

RESUMEN

There is evidence implicating abnormalities in the nitric oxide (NO) pathway in the development of glucocorticoid-induced hypertension (GC-HT). In humans, a reduction in NO availability during cortisol treatment has been observed. This study examined whether the NO donation may reverse the elevated blood pressure (BP) observed with cortisol treatment. A randomised double-blind, placebo-controlled, crossover study was undertaken in eight healthy men to address the effect of co-administration of isosorbide mononitrate (ISMN, 60 mg single dose, day 5) with cortisol (200 mg per day, days 1-6) and then compared with placebo (single dose, day 5) with cortisol. After a 2-week washout period, subjects crossed over to the alternate treatment. BP measurements were obtained using a mercury sphygmomanometer. Tonometry was used to estimate central pressures. There was a significant rise in mean arterial pressure with cortisol: 80 ± 3 vs 89 ± 3 mm Hg (day 1 vs day 5, cortisol+ISMN phase, P < 0.001) and 81 ± 3 vs 89 ± 3 mm Hg (day 1 vs day 5, cortisol+placebo phase, P < 0.01). ISMN significantly decreased aortic augmentation index: -17.3 ± 3.2 vs 1.8 ± 3.5%, (differences calculated from day 5-day 1, cortisol/ISMN vs cortisol+placebo, P < 0.001). These results demonstrated that GC-HT can be modified by co-administration of exogenous NO donors, consistent with the hypothesis that GC-HT is accompanied by reduced NO activity in humans.


Asunto(s)
Antiinflamatorios/efectos adversos , Hidrocortisona/efectos adversos , Hipertensión/tratamiento farmacológico , Dinitrato de Isosorbide/análogos & derivados , Donantes de Óxido Nítrico/uso terapéutico , Adulto , Presión Sanguínea/efectos de los fármacos , Monitoreo Ambulatorio de la Presión Arterial , Peso Corporal/efectos de los fármacos , Estudios Cruzados , Preparaciones de Acción Retardada , Método Doble Ciego , Voluntarios Sanos , Humanos , Hipertensión/sangre , Hipertensión/inducido químicamente , Dinitrato de Isosorbide/farmacología , Dinitrato de Isosorbide/uso terapéutico , Masculino , Nitratos/sangre , Donantes de Óxido Nítrico/farmacología , Nitritos/sangre , Adulto Joven
7.
Dis Esophagus ; 26(3): 263-71, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23551569

RESUMEN

The majority of esophagectomies in Western parts of the world are performed by a transthoracic approach reflecting the prevalence of adenocarcinoma of the lower esophagus or esophagogastric junction. Minimally invasive esophagectomy (MIE) has been reported in a variety of formats, but there are no series that directly compare totally minimally invasive thoracolaparoscopic 2 stage esophagectomy (MIE-2) with open Ivor Lewis (IVL). A prospective single-center cohort study of patients undergoing elective MIE-2 or IVL between January 2005 and November 2010 was performed. Short-term clinicopathologic outcomes were recorded using validated systems. One hundred and six patients (median age 66, range 36-85, 88 M : 18 F) underwent two-stage esophagectomy (53 MIE-2 and 53 IVL). Patient demographics (age, sex, body mass index, American Society of Anesthesiologists grade, tumor characteristics, neoadjuvant chemotherapy, and TNM stage) were comparable between the two groups. Outcomes for MIE-2 and IVL were comparable for anastomotic leak rates (5 [9%] vs. 2 [4%], P= 0.241), resection margin clearance (R0) (43 [81%] vs. 38 [72%], P= 0.253), median lymph node yield (19 vs. 18, P= 0.584), and median length of stay (12 [range 7-91] vs. 12 [range 7-101] days), respectively. Blood loss was significantly less for MIE-2 compared with IVL (median 300 [range 0-1250] mL vs. 400 [range 0-3000] mL, respectively, P= 0.021). MIE-2 in this series of selected patients supports its efficacy, when performed by an experienced minimally invasive surgical team. A well-designed multicenter trial addressing clinical effectiveness is now required.


Asunto(s)
Neoplasias Esofágicas/cirugía , Esofagectomía/métodos , Adenocarcinoma/cirugía , Adulto , Anciano , Anciano de 80 o más Años , Fuga Anastomótica/etiología , Pérdida de Sangre Quirúrgica , Quimioterapia Adyuvante , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Humanos , Laparoscopía/métodos , Laparotomía/métodos , Tiempo de Internación , Escisión del Ganglio Linfático , Masculino , Persona de Mediana Edad , Procedimientos Quirúrgicos Mínimamente Invasivos/métodos , Terapia Neoadyuvante , Recurrencia Local de Neoplasia/patología , Estadificación de Neoplasias , Tempo Operativo , Complicaciones Posoperatorias , Estudios Prospectivos , Toracoscopía/métodos , Toracotomía/métodos , Resultado del Tratamiento
8.
Nutr J ; 11: 84, 2012 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-23057785

RESUMEN

BACKGROUND: There is abundant research relevant to genetic and environmental influences on asthma and hayfever, but little is known about dietary risk factors in Australian adults. This study's purpose was to identify dietary factors associated with lifetime asthma (AS) and asthma or hayfever (AS/HF) diagnosis in Australian middle-aged and older adults. METHODS: From The 45 and Up Study baseline self-report data, this study included 156,035 adult men and women. Participants were sampled from the general population of New South Wales, Australia in 2006-2009. About 12% of participants reported ever receiving an AS diagnosis (men 10%; women 14%) and 23% reported AS/HF diagnosis (men 19%; women 26%). Following principle components factor analysis, dietary items loaded onto one of four factors for men (meats/cheese; fruits/vegetables; poultry/seafood; grains/alcohol) or five factors for women (meats; fruits/vegetables; poultry/seafood; cereal/alcohol; brown bread/cheese). Logistic regression was used to analyze the associations between dietary factors and AS or AS/HF diagnosis. RESULTS: For men, the meats/cheese factor was positively associated with AS (AOR = adjusted odds ratio for highest versus lowest quintile = 1.18, 95%CI = 1.08, 1.28; P(trend) = 0.001) and AS/HF (AOR for highest versus lowest quintile = 1.22, 95%CI = 1.14, 1.29; P(trend) < 0.001). Poultry/seafood was also associated with AS/HF in men (AOR for highest versus lowest quintile = 1.11, 95%CI = 1.04, 1.17; P(trend) = 0.002). For women, significant risk factors for AS/HF included meats (AOR for highest versus lowest quintile = 1.25, 95%CI = 1.19, 1.31; P(trend) = 0.001), poultry/seafood (AOR for highest versus lowest quintile = 1.06, 95%CI = 1.01, 1.12; P(trend) = 0.016), and fruits/vegetables (AOR for highest versus lowest quintile = 1.07, 95%CI = 1.02, 1.12; P(trend) = 0.011). In contrast, the cheese/brown bread dietary factor was protective against AS in women (AOR for highest versus lowest quintile = 0.88, 95%CI = 0.82, 0.94; P(trend) < 0.001). CONCLUSIONS: Generally, diets marked by greater intakes of meats, poultry, and seafood were associated with diagnosed AS and AS/HF. Taken together, these findings suggest that adherence to a more meat-based diet may pose risk for AS and AS/HF in Australian adults.


Asunto(s)
Envejecimiento , Asma/etiología , Dieta/efectos adversos , Rinitis Alérgica Estacional/etiología , Anciano , Anciano de 80 o más Años , Asma/epidemiología , Asma/prevención & control , Estudios de Cohortes , Estudios Transversales , Femenino , Humanos , Masculino , Carne/efectos adversos , Persona de Mediana Edad , Nueva Gales del Sur/epidemiología , Prevalencia , Análisis de Componente Principal , Estudios Prospectivos , Rinitis Alérgica Estacional/epidemiología , Rinitis Alérgica Estacional/prevención & control , Factores de Riesgo , Alimentos Marinos/efectos adversos , Caracteres Sexuales
9.
Neuroscience ; 180: 360-9, 2011 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-21320575

RESUMEN

Auditory function depends on gap junctional intercellular communication (GJIC) between fibrocytes within the cochlear spiral ligament, and basal cells and intermediate cells within stria vascularis. This communication within the lateral wall is hypothesized to support recirculation of K+ from perilymph to the intra-strial space, and thus is essential for the high [K+] measured within endolymph, and the generation of the endocochlear potential. In rats, the [K+] within endolymph reaches adult levels by postnatal day 7 (P7), several days before hearing onset, suggesting that GJIC matures before auditory responses are detectable. In this study we have mapped the postnatal development of GJIC within the cochlear lateral wall, to determine the stage at which direct communication first exists between the spiral ligament and stria vascularis. Connexin 30 immunofluorescence revealed a progressive increase of gap junction plaque numbers from P0 onwards, initially in the condensing mesenchyme behind strial marginal cells, and spreading throughout the lateral wall by P7-P8. Whole-cell patch clamp experiments revealed compartmentalized intercellular dye-coupling in the lateral wall between P2 and P5. There was extensive dye-coupling throughout the fibrocyte syncytium by P7. Also, by P7 dye introduced to fibrocytes could also be detected within strial basal cells and intermediate cells. These data suggest that lateral wall function matures several days in advance of hearing onset, and provide anatomical evidence of the existence of a putative K+ recirculation pathway within the cochlear lateral wall.


Asunto(s)
Comunicación Celular/fisiología , Cóclea/crecimiento & desarrollo , Cóclea/metabolismo , Uniones Comunicantes/metabolismo , Uniones Comunicantes/ultraestructura , Animales , Endolinfa/metabolismo , Técnica del Anticuerpo Fluorescente , Técnicas de Placa-Clamp , Potasio/metabolismo , Ratas , Ratas Sprague-Dawley
10.
Clin Exp Pharmacol Physiol ; 34(12): 1317-8, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-17973874

RESUMEN

1. Decreased nitric oxide (NO) availability is thought to be a feature of cortisol-induced hypertension in humans. 2. We hypothesized that, accordingly, the threshold for a depressor response to NO should be decreased by cortisol treatment. 3. We re-analysed data from a study of baroreflex function in normal men treated with cortisol using glyceryl trinitrate (GTN). 4. Cortisol treatment increased blood pressure and decreased the threshold dose of GTN for a fall in systolic and mean blood pressure. 5. These data support the notion that glucorticoid hypertension is associated with reduced NO bioavailability.


Asunto(s)
Hipertensión/tratamiento farmacológico , Donantes de Óxido Nítrico/uso terapéutico , Nitroglicerina/uso terapéutico , Adulto , Presión Sanguínea/efectos de los fármacos , Humanos , Hidrocortisona , Hipertensión/inducido químicamente , Hipertensión/fisiopatología , Masculino , Óxido Nítrico/metabolismo
11.
Phys Rev Lett ; 98(2): 022001, 2007 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-17358596

RESUMEN

A large data set of charged-pion (pi+/-) electroproduction from both hydrogen and deuterium targets has been obtained spanning the low-energy residual-mass region. These data conclusively show the onset of the quark-hadron duality phenomenon, as predicted for high-energy hadron electroproduction. We construct several ratios from these data to exhibit the relation of this phenomenon to the high-energy factorization ansatz of electron-quark scattering and subsequent quark-->pion production mechanisms.

12.
Kidney Int ; 71(2): 98-100, 2007 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17213856

RESUMEN

Chronic kidney disease (CKD) is associated with complex metabolic changes including insulin resistance. Siew et al. have highlighted an important relationship between insulin resistance and skeletal muscle protein turnover. If insulin resistance is implicated in sarcopenia of CKD, further research will be required to determine whether interventions that improve insulin sensitivity improve clinical outcomes and cardiovascular risk in CKD.


Asunto(s)
Enfermedades Cardiovasculares/prevención & control , Resistencia a la Insulina , Fallo Renal Crónico/terapia , Proteínas Musculares/metabolismo , Diálisis Renal , Enfermedades Cardiovasculares/etiología , Humanos , Resultado del Tratamiento
13.
Paediatr Anaesth ; 16(10): 1051-6, 2006 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-16972835

RESUMEN

BACKGROUND: Sleep disturbance has not been well quantified in pediatric postoperative management, yet has broad implications in pain management as well as upon the physical and psychological well-being of the young patient admitted for surgery. We aimed to describe sleep disturbance in this population using patient-controlled analgesia (PCA) and then identify the predictors of disturbed sleep. METHODS: A retrospective audit and analysis of sleep disturbance in postoperative pediatric patients using PCA devices were performed in a postoperative surgical ward population of a major tertiary referral center. PCA presses were used as a proxy measure of sleep. The description of the sleep disturbance included an unadjusted and adjusted analysis of the proposed predictors of sleep disturbance: age, sex, nature of presentation, operation type, PCA opioid type, presence of background infusion, postoperative night number, and adjuvant medication. All data were entered into an access database developed for the audit and analyzed using stata 8.0. RESULTS: The first 126 children prescribed PCA devices in the year 2004 were audited. One-third of patients in the population prescribed PCA experienced sleep disturbance. Observed predictors of sleep disturbance include older children (OR: 0.86, P=0.001) and those receiving a background infusion (OR: 0.19, P=0.002). Other predictors were not significant. CONCLUSIONS: Sleep disruption is common in children-prescribed PCA opioid analgesia. Older children and those receiving a background infusion were observed to experience less sleep. Other proposed predictors were not found to be reliable. Further investigation into the predictors of disturbed sleep in the postoperative patient is warranted.


Asunto(s)
Analgesia Controlada por el Paciente/efectos adversos , Analgesia Controlada por el Paciente/instrumentación , Complicaciones Posoperatorias/etiología , Trastornos del Sueño-Vigilia/etiología , Adolescente , Factores de Edad , Analgésicos Opioides/administración & dosificación , Analgésicos Opioides/uso terapéutico , Preescolar , Femenino , Fentanilo/administración & dosificación , Fentanilo/uso terapéutico , Humanos , Infusiones Intravenosas , Masculino , Morfina/administración & dosificación , Morfina/uso terapéutico , Complicaciones Posoperatorias/epidemiología , Valor Predictivo de las Pruebas , Estudios Retrospectivos , Factores de Riesgo , Factores Sexuales , Trastornos del Sueño-Vigilia/epidemiología , Procedimientos Quirúrgicos Operativos
14.
Phys Rev Lett ; 95(10): 102001, 2005 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-16196919

RESUMEN

We measured angular distributions of recoil-polarization response functions for neutral pion electroproduction for W = 1.23 GeV at Q(2) = 1.0 (GeV/c)(2), obtaining 14 separated response functions plus 2 Rosenbluth combinations; of these, 12 have been observed for the first time. Dynamical models do not describe quantities governed by imaginary parts of interference products well, indicating the need for adjusting magnitudes and phases for nonresonant amplitudes. We performed a nearly model-independent multipole analysis and obtained values for Re (S(1+)/M(1+)) = -(6.84 +/- 0.15)% and Re (E(1+)/M(1+)) = -(2.91 +/- 0.19)% that are distinctly different from those from the traditional Legendre analysis based upon M1+ dominance and ll(pi) < or = 1 truncation.

15.
Phys Rev Lett ; 94(19): 192302, 2005 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-16090165

RESUMEN

We have studied the quasielastic 3He(e,e(')p)2H reaction in perpendicular coplanar kinematics, with the energy and the momentum transferred by the electron fixed at 840 MeV and 1502 MeV/c, respectively. The 3He(e,e(')p)2H cross section was measured for missing momenta up to 1000 MeV/c, while the A(TL) asymmetry was extracted for missing momenta up to 660 MeV/c. For missing momenta up to 150 MeV/c, the cross section is described by variational calculations using modern 3He wave functions. For missing momenta from 150 to 750 MeV/c, strong final-state interaction effects are observed. Near 1000 MeV/c, the experimental cross section is more than an order of magnitude larger than predicted by available theories. The A(TL) asymmetry displays characteristic features of broken factorization with a structure that is similar to that generated by available models.

16.
Br J Anaesth ; 95(4): 524-9, 2005 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-16100236

RESUMEN

BACKGROUND: There are few data describing levobupivacaine pharmacokinetics in infants (<3 months) after caudal administration. METHODS: An open-label study was undertaken to examine the pharmacokinetics of levobupivacaine 2.5 mg ml(-1), 2 mg kg(-1) in children aged less than 3 months after single-shot caudal epidural administration. Plasma concentrations were determined at intervals from 0.5 to 4 h after injection. A population pharmacokinetic analysis of levobupivacaine time-concentration profiles (84 observations) from 22 infants with mean postnatal age (PNA) 2.0 (range 0.6-2.9) months was undertaken using non-linear mixed effects models (NONMEM). Time-concentration profiles were analysed using a one-compartment model with first-order input and first-order elimination. Estimates were standardized to a 70 kg adult using allometric size models. RESULTS: Population parameter estimates (between-subject variability) for total levobupivacaine were clearance (CLt) 12.8 [coefficient of variation (CV) 50.6%] litre h(-1) 70 kg(-1), volume of distribution (Vt) 202 (CV 31.6%) litre 70 kg(-1), absorption half-life (Tabs) 0.323 (CV 18.6%) h 70 kg(-1). Estimates for the unbound drug were clearance (CLfree) 104 (CV 43.5%) litre h(-1) 70 kg(-1), volume of distribution (Vfree) 1700 (CV 44.9%) litre 70 kg(-1), absorption half-life (Tabsfree) 0.175 (CV 83.7%) h 70 kg(-1). There was no effect attributable to PNA on CL or V. Time to peak plasma concentration (Tmax) was 0.82 (CV 18%) h. Peak plasma concentration (Cmax) was 0.69 (CV 25%) microg ml(-1) for total levobupivacaine and 0.09 (CV 37%) microg ml(-1) for unbound levobupivacaine. CONCLUSIONS: Clearance in infants is approximately half that described in adults, suggesting immaturity of P450 CYP3A4 and CYP1A2 enzyme isoforms that metabolize levobupivacaine in infants. This lower clearance delays Tmax, which was noted to occur approximately 50 min after administration of caudal epidural levobupivacaine.


Asunto(s)
Anestesia Caudal , Anestésicos Locales/sangre , Envejecimiento/sangre , Peso Corporal/fisiología , Bupivacaína/análogos & derivados , Bupivacaína/sangre , Femenino , Humanos , Lactante , Recién Nacido , Levobupivacaína , Masculino
17.
Phys Rev Lett ; 94(8): 082305, 2005 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-15783882

RESUMEN

Results of the Jefferson Lab Hall A quasielastic 3He(e,e'p)pn measurements are presented. These measurements were performed at fixed transferred momentum and energy, q=1502 MeV/c and omega=840 MeV, respectively, for missing momenta p(m) up to 1 GeV/c and missing energies in the continuum region, up to pion threshold; this kinematic coverage is much more extensive than that of any previous experiment. The cross section data are presented along with the effective momentum density distribution and compared to theoretical models.

18.
Phys Rev Lett ; 93(16): 166601, 2004 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-15525017

RESUMEN

Using an electrochemically gated transistor, we achieved controlled and reversible doping of poly(p-phenylene vinylene) in a large concentration range. Our data open a wide energy-window view on the density of states (DOS) and show, for the first time, that the core of the DOS function is Gaussian, while the low-energy tail has a more complex structure. The hole mobility increases by more than 4 orders of magnitude when the electrochemical potential is scanned through the DOS.

19.
Surg Endosc ; 18(6): 1001, 2004 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-15026918

RESUMEN

BACKGROUND: The use of a laparoscopic hand-assist device may aid in the identification of accessory spleens (ASs) and provide similar benefits to a conventional laparoscopic procedure. A patient with previous splenectomy for immune thrombocytopenic pupusa (ITP) and recurrent thrombocytopenia is reported. METHOD: A computed tomography scan and RBC scan identified several nodules consistent with ASs. Initial laparoscopic exploration could not identify all the ASs seen on preoperative imaging. A hand-assist device was placed and a total of five nodules of splenic tissue were identified without conversion to laparotomy. RESULTS: The patient had a brief and uncomplicated postoperative course with a return of platelet counts to 350,000 at 1-month follow-up. CONCLUSION: We propose that in the scenario of recurrent ITP following laparoscopic splenectomy, repeat laparoscopy is the first step once an AS is identified by preoperative imaging. If the AS is not identified at laparoscopy, the insertion of a hand-assist device is an alternative to a full laparotomy.


Asunto(s)
Laparoscopía/métodos , Púrpura Trombocitopénica Idiopática/cirugía , Bazo/anomalías , Esplenectomía/instrumentación , Anomalías Congénitas/diagnóstico , Anomalías Congénitas/cirugía , Femenino , Mano , Humanos , Persona de Mediana Edad , Procedimientos Quirúrgicos Mínimamente Invasivos , Palpación , Púrpura Trombocitopénica Idiopática/complicaciones , Recurrencia , Bazo/cirugía , Esplenectomía/métodos , Trombocitopenia/etiología
20.
Surg Endosc ; 18(9): 1340-3, 2004 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-15803233

RESUMEN

BACKGROUND: Hand-assisted laparoscopic surgery (HALS) devices may be well suited to splenectomy in cases of splenomegaly. METHODS: All cases of HALS for splenectomy between 1997 and 2001 were reviewed. Patient characteristics, operative details, and morbidity and mortality were analyzed. RESULTS: HALS for splenectomy was performed in 54 patients. A total of 39 patients with massive splenomegaly (MS) (>600 g) were identified. The average weight of the MS group was 1285 +/- 505 g. There was one (3%) conversion. Operative time was 159 +/- 65 min, estimated blood loss was 257 +/- 240 ml, and length of hospital stay was 5.4 +/- 2.9 days. Morbidity was limited to 13 patients (24%), and there were two postoperative mortalities (5.1%). CONCLUSIONS: HALS for splenectomy in the setting of splenomegaly is feasible and safe. For the surgeon considering a laparoscopic approach in the setting of splenomegaly, a hand-assisted technique is ideally suited for removal of the enlarged spleen.


Asunto(s)
Laparoscopía/métodos , Esplenectomía/métodos , Enfermedades del Bazo/cirugía , Esplenomegalia/cirugía , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Enfermedades del Bazo/complicaciones , Esplenomegalia/etiología
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