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BACKGROUND: A difficult airway is anticipated with cervical spine injuries (CSIs) as immobilization techniques such as manual in-line stabilization (MILS) are used, which distort the oro-pharyngeal-laryngeal axis. Video laryngoscopes (VLs) make difficult airway management easy, as they do not require axis alignment. The present study aimed to compare the total time taken by Macintosh laryngoscope (ML), conventional blade, and D-blade ™ of C-MAC ® VL in simulated CSI scenarios using MILS. METHODS: Ninety patients were randomly allocated into three groups: Group M (ML), Group C (conventional blade of C-MAC ® ), and Group D (D-blade ™ of C-MAC ® ) with MILS applied before intubation. Primary outcome was the total time taken for successful intubation, while secondary outcomes were to assess Cormack-Lehane (CL) grade, number of attempts, hemodynamic response, and associated complications. RESULTS: Total time for intubation in Group C was 23.40 ± 7.06 sec compared to 35.27 ± 6.53 and 47.27 ± 2.53 sec in groups D and M, respectively ( P < 0.001). CL-grade I was observed in 15/30 (50%) in Group M, 25/30 (83.3%) in Group C, and 29/30 (96.7%) in Group D. Group M reported 7/30 (23.3%) failed intubations, while none were observed in other groups. Hemodynamic parameters were significantly higher at 3 and 5 min in Group M. Postoperative sore throat was recorded in 12/30 (40%) in Group M compared to 3/30 (10%) in groups C and D each ( P value 0.037). CONCLUSION: C-MAC ® VL requires less time for intubation, provides better glottic view, and has higher success, with better attenuation of hemodynamic response and fewer complications compared to ML.
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Intubación Intratraqueal , Laringoscopios , Laringoscopía , Humanos , Intubación Intratraqueal/métodos , Intubación Intratraqueal/instrumentación , Intubación Intratraqueal/efectos adversos , Masculino , Femenino , Adulto , Laringoscopía/métodos , Persona de Mediana Edad , Inmovilización/métodos , Vértebras Cervicales , Traumatismos Vertebrales/terapia , Factores de Tiempo , Diseño de Equipo , Manejo de la Vía Aérea/métodosRESUMEN
BACKGROUND: Prehospital analgesia is often required after traumatic injury, currently morphine is the strongest parenteral analgesia routinely available for use by paramedics in the United Kingdom (UK) when treating patients with severe pain. This protocol describes a multi-centre, randomised, double blinded trial comparing the clinical and cost-effectiveness of ketamine and morphine for severe pain following acute traumatic injury. METHODS: A two arm pragmatic, phase III trial working with two large NHS ambulance services, with an internal pilot. Participants will be randomised in equal numbers to either (1) morphine or (2) ketamine by IV/IO injection. We aim to recruit 446 participants over the age of 16 years old, with a self-reported pain score of 7 or above out of 10. Randomised participants will receive a maximum of 20 mg of morphine, or a maximum of 30 mg of ketamine, to manage their pain. The primary outcome will be the sum of pain intensity difference. Secondary outcomes measure the effectiveness of pain relief and overall patient experience from randomisation to arrival at hospital as well as monitoring the adverse events, resource use and cost-effectiveness outcomes. DISCUSSION: The PACKMAN study is the first UK clinical trial addressing the clinical and cost-effectiveness of ketamine and morphine in treating acute severe pain from traumatic injury treated by NHS paramedics. The findings will inform future clinical practice and provide insights into the effectiveness of ketamine as a prehospital analgesia. TRIAL REGISTRATION: ISRCTN, ISRCTN14124474. Registered 22 October 2020, https://www.isrctn.com/ISRCTN14124474.
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Dolor Agudo , Analgesia , Ketamina , Humanos , Adolescente , Ketamina/uso terapéutico , Ketamina/efectos adversos , Morfina/uso terapéutico , Paramédico , Resultado del Tratamiento , Método Doble Ciego , Analgesia/métodos , Dolor Agudo/tratamiento farmacológico , Dolor Agudo/etiología , Analgésicos Opioides/uso terapéutico , Ensayos Clínicos Controlados Aleatorios como Asunto , Estudios Multicéntricos como AsuntoRESUMEN
Hyperosmolar solutions are widely used to treat raised intracranial pressure following severe traumatic brain injury. Although mannitol has historically been the most frequently administered, hypertonic saline solutions are increasingly being used. However, definitive evidence regarding their comparative effectiveness is lacking. The Sugar or Salt Trial is a UK randomised, allocation concealed open label multicentre pragmatic trial designed to determine the clinical and cost-effectiveness of hypertonic saline compared with mannitol in the management of patients with severe traumatic brain injury. Patients requiring intensive care unit admission and intracranial pressure monitoring post-traumatic brain injury will be allocated at random to receive equi-osmolar boluses of either mannitol or hypertonic saline following failure of routine first-line measures to control intracranial pressure. The primary outcome for the study will be the Extended Glasgow Outcome Scale assessed at six months after randomisation. Results will inform current clinical practice in the routine use of hyperosmolar therapy as well as assess the impact of potential side effects. Pre-planned longer term clinical and cost effectiveness analyses will further inform the use of these treatments.
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BACKGROUND: The PARAMEDIC cluster randomised trial evaluated the LUCAS mechanical chest compression device, and did not find evidence that use of mechanical chest compression led to an improvement in survival at 30 days. This paper reports patient outcomes from admission to hospital to 12 months after randomisation. METHODS: Information about hospital length of stay and intensive care management was obtained through linkage with Hospital Episode Statistics and the Intensive Care National Audit and Research Centre. Patients surviving to hospital discharge were approached to complete questionnaires (SF-12v2, EQ-5D, MMSE, HADS and PTSD-CL) at 90days and 12 months. The study is registered with Current Controlled Trials, number ISRCTN08233942. RESULTS: 377 patients in the LUCAS arm and 658 patients in the manual chest compression were admitted to hospital. Hospital and intensive care length of stay were similar. Long term follow-up assessments were limited by poor response rates (53.7% at 3 months and 55.6% at 12 months). Follow-up rates were lower in those with worse neurological function. Among respondents, long term health related quality of life outcomes and emotional well-being was similar between groups. Cognitive function, measured by MMSE, was marginally lower in the LUCAS arm mean 26.9 (SD 3.7) compared to control mean 28.0 (SD 2.3), adjusted mean difference -1.5 (95% CI -2.6 to -0.4). CONCLUSION: There were no clinically important differences identified in outcomes at long term follow-up between those allocated to the mechanical chest compression compared to those receiving manual chest compression.
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Reanimación Cardiopulmonar/métodos , Masaje Cardíaco/métodos , Paro Cardíaco Extrahospitalario/terapia , Medición de Resultados Informados por el Paciente , Calidad de Vida , Reanimación Cardiopulmonar/instrumentación , Estudios de Casos y Controles , Masaje Cardíaco/instrumentación , Humanos , Unidades de Cuidados Intensivos/estadística & datos numéricos , Tiempo de Internación/estadística & datos numéricos , Oportunidad Relativa , Paro Cardíaco Extrahospitalario/mortalidad , Estudios Prospectivos , Encuestas y Cuestionarios , Sobrevivientes/estadística & datos numéricosRESUMEN
While Vagus Nerve Stimulation (VNS) is proven to be a safe and effective adjunctive therapy in the general population with medically intractable seizures, little is published about its implantation during pregnancy. Here we illustrate the case of a 21year old primigravid woman with medically refractory seizures who underwent safe and successful VNS implantation and immediate activation of the device in her 32nd week of pregnancy, resulting in dramatically improved seizure control and subsequent delivery of a healthy baby.
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Epilepsia Refractaria/cirugía , Epilepsia Refractaria/terapia , Neuroestimuladores Implantables , Estimulación del Nervio Vago , Femenino , Humanos , Embarazo , Resultado del Tratamiento , Adulto JovenRESUMEN
BACKGROUND.: The acute respiratory distress syndrome (ARDS) is a condition with a high mortality and morbidity. Mechanical ventilation prevents immediate mortality but may further damage patients' lungs. Low tidal volume lung-protective strategies have been shown to increase survival by reducing this iatrogenic damage. Current guidelines recommend tidal volumes of 6-8 ml kg -1 of predicted body weight. We used data from three large randomized controlled trials of treatments for ARDS to determine compliance with these recommendations. METHODS.: We used the tidal volume recorded at randomization for all patients in the OSCAR, HARP-2, and BALTI-2 studies. In addition, we used the ventilation data for control arm patients in OSCAR and all patients in HARP-2 at days 1 and 7 after randomization. RESULTS.: The three trials enrolled 1660 patients, with tidal volume data available at least at one time point in 1412 patients. Compliance with the 6-8 ml kg -1 recommendation for tidal volume ranged from 20 to 39% of patients across all time points in all three trials. CONCLUSION.: Poor compliance with the guidelines for tidal volume in patients with ARDS has been demonstrated before in case series, but not in clinical trials where the patient population is specifically selected against standard ARDS diagnostic criteria and the investigators were encouraged to use low tidal volumes. This study may indicate a need to improve implementation and compliance with protective lung ventilation.
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Síndrome de Dificultad Respiratoria/fisiopatología , Volumen de Ventilación Pulmonar , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Interpretación Estadística de Datos , Femenino , Adhesión a Directriz , Humanos , Masculino , Persona de Mediana Edad , Ensayos Clínicos Controlados Aleatorios como Asunto/estadística & datos numéricos , Respiración Artificial/estadística & datos numéricos , Pruebas de Función Respiratoria , Adulto JovenRESUMEN
AIM: This study explores why resuscitation is withheld when emergency medical staff arrive at the scene of a cardiac arrest and identifies modifiable factors associated with this decision. METHODS: This is a secondary analysis of unselected patients who sustained an out of hospital cardiac arrest attended by ambulance vehicles participating in a randomized controlled trial of a mechanical chest compression device (PARAMEDIC trial). Patients were categorized as 'non-resuscitation' patients if there was a do-not-attempt-cardiopulmonary-resuscitation (DNACPR) order, signs unequivocally associated with death or resuscitation was deemed futile (15min had elapsed since collapse with no bystander-CPR and asystole recorded on EMS arrival). RESULTS: Emergency Medical Services attended 11,451 cardiac arrests. Resuscitation was attempted or continued by Emergency Medical Service staff in 4805 (42%) of cases. Resuscitation was withheld in 6646 cases (58%). 711 (6.2%) had a do not attempt resuscitation decision, 4439 (38.8%) had signs unequivocally associated with death and in 1496 cases (13.1%) CPR was considered futile. Those where resuscitation was withheld due to futility were characterised by low bystander CPR rates (7.2%) and by being female. CONCLUSIONS: Resuscitation was withheld by ambulance staff in over one in ten (13.1%) victims of out of hospital cardiac arrest on the basis of futility. These cases were associated with a very low rate of bystander CPR. Future studies should explore strengthening the 'Chain of Survival' to increase the community bystander CPR response and evaluate the effect on the numbers of survivors from out of hospital cardiac arrest.
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Reanimación Cardiopulmonar/estadística & datos numéricos , Servicios Médicos de Urgencia/métodos , Inutilidad Médica , Paro Cardíaco Extrahospitalario/mortalidad , Órdenes de Resucitación , Privación de Tratamiento/estadística & datos numéricos , Adulto , Anciano , Anciano de 80 o más Años , Muerte , Servicios Médicos de Urgencia/estadística & datos numéricos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Tiempo de TratamientoRESUMEN
Because of insufficient understanding of the molecular effects of low levels of radiation exposure, there is a great uncertainty regarding its health risks. We report here that treatment of normal human cells with low-dose radiation induces a metabolic shift from oxidative phosphorylation to aerobic glycolysis resulting in increased radiation resistance. This metabolic change is highlighted by upregulation of genes encoding glucose transporters and enzymes of glycolysis and the oxidative pentose phosphate pathway, concomitant with downregulation of mitochondrial genes, with corresponding changes in metabolic flux through these pathways. Mechanistically, the metabolic reprogramming depends on HIF1α, which is induced specifically by low-dose irradiation linking the metabolic pathway with cellular radiation dose response. Increased glucose flux and radiation resistance from low-dose irradiation are also observed systemically in mice. This highly sensitive metabolic response to low-dose radiation has important implications in understanding and assessing the health risks of radiation exposure.
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Subunidad alfa del Factor 1 Inducible por Hipoxia/efectos de la radiación , Mitocondrias/efectos de la radiación , Adaptación Fisiológica , Animales , Linfocitos B/efectos de la radiación , Línea Celular Tumoral , Relación Dosis-Respuesta en la Radiación , Fibroblastos/efectos de la radiación , Glucólisis/efectos de la radiación , Humanos , Ratones , Ratones Endogámicos BALB C , Fosforilación Oxidativa/efectos de la radiaciónRESUMEN
Most chemotherapeutical drugs kill cancer cells chiefly by inducing DNA damage, which unfortunately also causes undesirable injuries to normal tissues, mainly due to p53 activation. We report a novel strategy of normal tissue protection that involves p53/NF-κB coordinated metabolic regulation. Pretreatment of untransformed cells with low doses of arsenic induced concerted p53 suppression and NF-κB activation, which elicited a marked induction of glycolysis. Significantly, this metabolic shift provided cells effective protection against cytotoxic chemotherapy, coupling the metabolic pathway to cellular resistance. Using both in vitro and in vivo models, we demonstrated an absolute requirement of functional p53 in arsenic-mediated protection. Consistently, a brief arsenic pretreatment selectively protected only normal tissues, but not tumors, from toxicity of chemotherapy. An indispensable role of glycolysis in protecting normal tissues was demonstrated by using an inhibitor of glycolysis, 2-deoxyglucose, which almost totally abolished low-dose arsenic-mediated protection. Together, our work demonstrates that low-dose arsenic renders normal cells and tissues resistant to chemotherapy-induced toxicity by inducting glycolysis.
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Antineoplásicos/uso terapéutico , Arsénico/farmacología , FN-kappa B/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Células Cultivadas , Relación Dosis-Respuesta a Droga , HumanosRESUMEN
OBJECTIVES: To estimate the clinical effectiveness of active management (AM) in general practice versus AM plus a group-based, professionally led cognitive behavioural approach (CBA) for subacute and chronic low back pain (LBP) and to measure the cost of each strategy over a period of 12 months and estimate cost-effectiveness. DESIGN: Pragmatic multicentred randomised controlled trial with investigator-blinded assessment of outcomes. SETTING: Fifty-six general practices from seven English regions. PARTICIPANTS: People with subacute and chronic LBP who were experiencing symptoms that were at least moderately troublesome. INTERVENTIONS: Participants were randomised (in a ratio of 2:1) to receive either AM+CBA or AM alone. MAIN OUTCOME MEASURES: Primary outcomes were the Roland Morris Disability Questionnaire (RMQ) and the Modified Von Korff Scale (MVK), which measure LBP and disability. Secondary outcomes included mental and physical health-related quality of life (Short Form 12-item health survey), health status, fear avoidance beliefs and pain self-efficacy. Cost-utility of CBA was considered from both the UK NHS perspective and a broader health-care perspective, including both NHS costs and costs of privately purchased goods and services related to LBP. Quality-adjusted life-years (QALYs) were calculated from the five-item EuroQoL. RESULTS: Between April 2005 and April 2007, 701 participants were randomised: 233 to AM and 468 to AM+CBA. Of these, 420 were female. The mean age of participants was 54 years and mean baseline RMQ was 8.7. Outcome data were obtained for 85% of participants at 12 months. Benefits were seen across a range of outcome measures in favour of CBA with no evidence of group or therapist effects. CBA resulted in at least twice as much improvement as AM. Mean additional improvement in the CBA arm was 1.1 [95% confidence interval (CI) 0.4 to 1.7], 1.4 (95% CI 0.7 to 2.1) and 1.3 (95% CI 0.6 to 2.1) change points in the RMQ at 3, 6 and 12 months respectively. Additional improvement in MVK pain was 6.8 (95% CI 3.5 to 10.2), 8.0 (95% CI 4.3 to 11.7) and 7.0 (95% CI 3.2 to 10.7) points, and in MVK disability was 4.3 (95% CI 0.4 to 8.2), 8.1 (95% CI 4.1 to 12.0) and 8.4 (95% CI 4.4 to 12.4) points at 3, 6 and 12 months respectively. At 12 months, 60% of the AM+CBA arm and 31% of the AM arm reported some or complete recovery. Mean cost of attending a CBA course was 187 pounds per participant with an additional benefit in QALYs of 0.099 and an additional cost of 178.06 pounds. Incremental cost-effectiveness ratio was 1786.00 pounds. Probability of CBA being cost-effective reached 90% at about 3000 pounds and remained at that level or above; at a cost-effectiveness threshold of 20,000 pounds the CBA group had an almost 100% probability of being considered cost-effective. User perspectives on the acceptability of group treatments were sought through semi-structured interviews. Most were familiar with key messages of AM; most who had attended any group sessions had retained key messages from the sessions and two-thirds talked about a reduction in fear avoidance and changes in their behaviour. Group sessions appeared to provide reassurance, lessen isolation and enable participants to learn strategies from each other. CONCLUSIONS: Long-term effectiveness and cost-effectiveness of CBA in treating subacute and chronic LBP was shown, making this intervention attractive to patients, clinicians and purchasers. Short-term (3-month) clinical effects were similar to those found in high-quality studies of other therapies and benefits were maintained and increased over the long term (12 months). Cost per QALY was about half that of competing interventions for LBP and because the intervention can be delivered by existing NHS staff following brief training, the back skills training programme could be implemented within the NHS with relative ease. TRIAL REGISTRATION: Current Controlled Trials ISRCTN37807450. FUNDING: The National Institute for Health Research Health Technology Assessment programme.
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Competencia Clínica , Terapia Cognitivo-Conductual , Dolor de la Región Lumbar/terapia , Atención Primaria de Salud/métodos , Intervalos de Confianza , Análisis Costo-Beneficio , Femenino , Costos de la Atención en Salud , Conocimientos, Actitudes y Práctica en Salud , Indicadores de Salud , Encuestas Epidemiológicas , Humanos , Dolor de la Región Lumbar/economía , Dolor de la Región Lumbar/psicología , Masculino , Persona de Mediana Edad , Evaluación de Resultado en la Atención de Salud/economía , Desarrollo de Programa , Evaluación de Programas y Proyectos de Salud , Psicometría , Calidad de Vida , Años de Vida Ajustados por Calidad de Vida , Método Simple Ciego , Encuestas y Cuestionarios , Reino UnidoRESUMEN
BACKGROUND: The aim was to compare effectiveness of group versus individual sessions of physiotherapy in terms of symptoms, quality of life, and costs, and to investigate the effect of patient preference on uptake and outcome of treatment. METHODS: A pragmatic, multi-centre randomised controlled trial in five British National Health Service physiotherapy departments. 174 women with stress and/or urge incontinence were randomised to receive treatment from a physiotherapist delivered in a group or individual setting over three weekly sessions. Outcome were measured as Symptom Severity Index; Incontinence-related Quality of Life questionnaire; National Health Service costs, and out of pocket expenses. RESULTS: The majority of women expressed no preference (55%) or preference for individual treatment (36%). Treatment attendance was good, with similar attendance with both service delivery models. Overall, there were no statistically significant differences in symptom severity or quality of life outcomes between the models. Over 85% of women reported a subjective benefit of treatment, with a slightly higher rating in the individual compared with the group setting. When all health care costs were considered, average cost per patient was lower for group sessions (Mean cost difference 52.91 pounds 95%, confidence interval ( 25.82 pounds- 80.00 pounds)). CONCLUSION: Indications are that whilst some women may have an initial preference for individual treatment, there are no substantial differences in the symptom, quality of life outcomes or non-attendance. Because of the significant difference in mean cost, group treatment is recommended. TRIAL REGISTRATION NUMBER: ISRCTN 16772662.
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Terapia por Ejercicio/métodos , Costos de la Atención en Salud , Calidad de Vida , Incontinencia Urinaria/economía , Incontinencia Urinaria/rehabilitación , Adulto , Anciano , Análisis Costo-Beneficio , Terapia por Ejercicio/economía , Femenino , Humanos , Persona de Mediana Edad , Prioridad del Paciente , Modalidades de Fisioterapia/economía , Probabilidad , Relaciones Profesional-Paciente , Índice de Severidad de la Enfermedad , Perfil de Impacto de Enfermedad , Método Simple Ciego , Medicina Estatal , Estrés Psicológico , Resultado del Tratamiento , Reino Unido , Incontinencia Urinaria/diagnóstico , Incontinencia Urinaria/psicologíaRESUMEN
BACKGROUND: Improving quality of end-of-life care is a key driver of UK policy. The Gold Standards Framework (GSF) for Palliative Care aims to strengthen primary palliative care through facilitating implementation of systematic clinical and organisational processes. OBJECTIVES: To describe the general practices that participated in the GSF programme in 2003-5 and the changes in process and perception of quality that occurred in the year following entry into the programme, and to identify factors associated with the extent of change. METHODS: Participating practices completed a questionnaire at baseline and another approximately 12 months later. Data were derived from categorical questions about the implementation of 35 organisational and clinical processes, and self-rated assessments of quality, associated with palliative care provision. PARTICIPANTS: 1305 practices (total registered population almost 10 million). Follow-up questionnaire completed by 955 (73.2%) practices (after mean (SD) 12.8 (2.8) months; median 13 months). FINDINGS: Mean increase in total number of processes implemented (maximum = 35) was 9.6 (95% CI 9.0 to 10.2; p<0.001; baseline: 15.7 (SD 6.4), follow-up: 25.2 (SD 5.2)). Extent of change was largest for practices with low baseline scores. Aspects of process related to coordination and communication showed the greatest change. All dimensions of quality improved following GSF implementation; change was highest for the "quality of palliative care for cancer patients" and "confidence in assessing, recording and addressing the physical and psychosocial areas of patient care". CONCLUSION: Implementation of the GSF seems to have resulted in substantial improvements in process and quality of palliative care. Further research is required of the extent to which this has enhanced care (physical, practical and psychological outcomes) for patients and carers.
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Cuidados Paliativos/normas , Calidad de la Atención de Salud , Inglaterra , Medicina Familiar y Comunitaria/normas , Humanos , Irlanda , Evaluación de Procesos y Resultados en Atención de Salud , Pautas de la Práctica en MedicinaRESUMEN
Intraparenchymal pericatheter cyst is a rare complication of shunt surgery. It occurs as a consequence of increased CSF outflow resistance distal to a patent ventricular catheter. Treatment has traditionally consisted of shunt revision. We report on two such cases managed conservatively. The role of shunt revisions in cases with asymptomatic intraparenchymal pericatheter cyst is debatable.
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Cateterismo/efectos adversos , Quistes/etiología , Derivación Ventriculoperitoneal/efectos adversos , Derivación Ventriculoperitoneal/instrumentación , Encéfalo/anomalías , Preescolar , Quistes/diagnóstico por imagen , Humanos , Hidrocefalia/cirugía , Imagen por Resonancia Magnética , Masculino , Meningomielocele/cirugía , Reoperación , Tomografía Computarizada por Rayos XRESUMEN
Conjugated linoleic acid (CLA) is found naturally in dairy and beef products at levels of 0.2% to 2% of the total fat. A more concentrated source of dietary CLA, low in saturated fat, would be highly desirable to obtain optimum CLA levels of about 3 g/d. We recently reported photoisomerization of soy oil with iodine catalysis to be a simple way of producing CLA in laboratory without high-energy input or expensive enzymes and microorganisms. However, a long irradiation time of 144 h has been a limitation for this technique to be of practical value. The objectives of this study were to build a pilot plant unit to rapidly produce high-CLA soy oil by photoirradiation and optimize the processing parameters to obtain high-CLA soy oil. Degassed oil with dissolved-iodine catalyst was irradiated by UV lamps in an illuminated laminar flow unit (ILFU). The ILFU consists of 2 borosilicate glass plates in a silicone lined stainless steel frame. The static mode of operation yielded 5.7% of total CLA isomers and performed twice as well than the continuous mode with 2.5% of total CLA. Irradiating oil in a static mode with reflective surfaces increased the CLA yields 3-fold to 16.4%. About 22% of total CLA isomers can be rapidly produced from soy oil linoleic acid with 0.35% iodine catalyst in a 0.5-cm-thick oil layer maintained at 48 degrees C for 12 h. The peroxide value and GC-MS analysis did not identify any volatile compounds characteristic of lipid oxidation. This study is a definitive step toward the commercialization of large-scale production of CLA-rich soy oil.
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Manipulación de Alimentos/métodos , Luz , Ácidos Linoleicos Conjugados/análisis , Aceite de Soja/química , Cromatografía de Gases y Espectrometría de Masas , Yodo/química , Peroxidación de Lípido , Oxidación-Reducción , Fotoquímica , Proyectos PilotoRESUMEN
INTRODUCTION: Intra-abdominal pressure (IAP) is increasingly being considered as an important physiologic parameter to be measured in critically ill patients. Traditional methods of monitoring IAP rely on intermittent IAP (IIAP) measurements using indwelling bladder catheters. Recently, a method of continuous IAP (CIAP) monitoring has been developed using a three-way bladder catheter. This study evaluates the reliability of IIAP and CIAP measurement techniques using an in vitro model. METHODS: An in vitro model of the abdomen was constructed using a 50 l container with a 100 ml infusion bag at the base to simulate a bladder. A three-way catheter tip was centered within the infusion bag filled with 50 ml saline. To simulate IAP the container was filled with water at 5 cm H(2)O increments from 10 to 25 cm H(2)O. Pressures were recorded by observers from a bedside monitor interfaced with a three-way Foley catheter using alternating intermittent and continuous techniques. Each subject was blinded to the known pressure values. Descriptive statistics and a generalised estimating equation (GEE) was used to describe the relationship of IIAP and CIAP to known pressures. RESULTS: One hundred and thirty-two (132) observations were made by 20 subjects for both IIAP and CIAP estimates. In 45.5% of IIAP measures, the estimate was correct, and it was never more than 1 cm H(2)O different from the actual. Similarly, in 38.6% of CIAP measures, the estimate was correct, and was never more than 2 cm H(2)O from the actual. The GEE regression coefficients comparing known pressures with IIAP and CIAP were 1.007 and 0.976 respectively. The minimum and maximum pressure deviations never exceeded more than 1.3 cm H(2)O from the actual. CONCLUSION: Intermittent IAP and CIAP are both reliable and reproducible methods to measure IAP in an in vitro model. There exists a direct and significant association between both measurements and the actual value. Neither measure was shown to be superior.
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Abdomen/fisiopatología , Monitoreo Fisiológico/métodos , Diseño de Equipo , Humanos , Manometría/métodos , Presión , Estudios ProspectivosRESUMEN
The unexpectedly long, and still unfinished, path towards a reliable mathematical model of glycolysis and its regulation in Lactococcus lactis is described. The model of this comparatively simple pathway was to be deduced from in vivo nuclear magnetic resonance time-series measurements of the key glycolytic metabolites. As to be expected from any nonlinear inverse problem, computational challenges were encountered in the numerical determination of parameter values of the model. Some of these were successfully solved, whereas others are still awaiting improved techniques of analysis. In addition, rethinking of the model formulation became necessary, because some generally accepted assumptions during model design are not necessarily valid for in vivo models. Examples include precursor-product relationships and the homogeneity of cells and their responses. Finally, it turned out to be useful to model only some of the metabolites, while using time courses of ubiquitous compounds such as adenosine triphosphate, inorganic phosphate, nicotinamide adenine dinucleotide (oxidised) and nicotinamide adenine dinucleotide (reduced) as unmodelled input functions. With respect to our specific application, the modelling process has come a long way, but it is not yet completed. Nonetheless, the model analysis has led to interesting insights into the design of the pathway and into the principles that govern its operation. Specifically, the widely observed feedforward activation of pyruvate kinase by fructose 1,6-bisphosphate is shown to provide a crucial mechanism for positioning the starving organism in a holding pattern that allows immediate uptake of glucose, as soon as it becomes available.
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Glucosa/metabolismo , Glucólisis/fisiología , Ácido Láctico/metabolismo , Lactococcus lactis/metabolismo , Modelos Biológicos , Transducción de Señal/fisiología , Biología de Sistemas/métodos , Simulación por Computador , Retroalimentación/fisiologíaRESUMEN
There has been increasing emphasis in medical research on the design and analysis of quality of life scales. Many quality of life scales are ordinal and statistical methods such as ordinal regression models have been reviewed on a number of occasions. However, when such models are applied, the way the data have been generated is often overlooked. In this paper we illustrate the use of ordinal regression models, in particular the proportional odds model, the partial proportional odds model and the stereotype model in the MRC Cognitive Function and Ageing Study (MRC CFAS). The partial proportional odds and the stereotype models are often under-utilized, perhaps due to the lack of available software. However, in this paper, analysis based on these models has been carried out using the popular statistical software package SAS and macros devised in SAS. Furthermore, bootstrapping techniques have been applied to obtain valid estimates of the standard errors of the parameters in the stereotype model. Strikingly different results were obtained using the different ordinal regression models. We conclude that the way the data have been generated is particularly important for the analysis of quality of life assessments. Different methods of generating scores yield data with different properties. It is now possible to fit a variety of ordinal regression models and so select the appropriate one that correctly models the data.
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Modelos Estadísticos , Calidad de Vida , Análisis de Regresión , Investigación , Interpretación Estadística de Datos , Humanos , Oportunidad Relativa , Programas Informáticos , Reino UnidoRESUMEN
Health Related Quality of Life (HRQoL) measures are becoming more frequently used in clinical trials, as both primary and secondary endpoints. Investigators are now asking statisticians for advice on how to plan (e.g., sample size) and analyze studies using HRQoL measures. HRQoL measures such as the SF-36 are usually measured on an ordered categorical (ordinal) scale. In the designing stages and when analyzing, the scales are often scored and the scores treated as if they were continuous and normally distributed. However the ordinal scaling of HRQoL measures leads to problems in determining sample size, and conventional parametric methods of estimation and hypothesis testing may not be appropriate for such outcomes. We present practical guidelines for the design and analysis of trials with HRQoL measures as outcomes. We used conventional statistical methods (i.e., t-tests and multiple regression), various ordinal regression models (proportional odds, continuation ratio, polytomous and stereotype) and bootstrap methods to analyze an HRQoL dataset. To illustrate the various methods we used HRQoL data on the SF-36 Role Limitations Emotional dimension for two groups of patients with leg ulcers. The bootstrap, t-test, and multiple regression methods gave similar results. The various ordinal regression models also gave similar results. If the HRQoL measure has a large number of ordered categories, most of which are occupied, and the underlying scale really is continuous but measured imperfectly by an instrument with a limited number of discrete values, then an informal rule of thumb is that this discrete scale should be treated as continuous if it has seven or more categories and as ordinal otherwise.
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Ensayos Clínicos como Asunto/estadística & datos numéricos , Calidad de Vida , Proyectos de Investigación/estadística & datos numéricos , Resultado del Tratamiento , Algoritmos , Análisis de Varianza , Intervalos de Confianza , Humanos , Modelos Logísticos , Modelos Estadísticos , Escalas de Valoración Psiquiátrica , Calidad de Vida/psicología , Análisis de Regresión , Encuestas y CuestionariosRESUMEN
Previous research suggests that mentor relationships are facilitative of career success, career satisfaction, and retention in organizations. Yet, little research has been done to explore the prevalence or function of mentor relationships in military populations. In this study, preliminary data were collected regarding the prevalence of mentor relationship experiences among 576 third year midshipmen at the U.S. Naval Academy. Only 40% of respondents had ever experienced a mentor relationship. Most mentors were senior military personnel, and 87% were male. Most relationships were mutually initiated, and they tended to last for several years. Although both career and psychosocial mentor functions were present in these relationships, psychosocial functions were most notable and most highly correlated with positive appraisals of mentor relationships. Midshipmen viewed mentoring as extremely important and rated their own mentor relationships as extremely positive. Implications for further research on mentoring are discussed.
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Relaciones Interprofesionales , Mentores/psicología , Personal Militar/psicología , Medicina Naval , Estudiantes/psicología , Adulto , Movilidad Laboral , Femenino , Humanos , Satisfacción en el Trabajo , Masculino , Personal Militar/educación , Encuestas y Cuestionarios , Estados UnidosRESUMEN
The commercially available ICT Card Test for bancroftian filariasis was evaluated for its sensitivity and specificity in detecting microfilaria carriers among 189 individuals each in filariasis-endemic and nonendemic areas in South India, and compared to both conventional night blood finger prick thick blood smear examination and venous blood membrane filtration. Though the specificity of the test was 100% in comparison to both, the sensitivity was 98.5% against the finger prick thick blood smear and 71.9 compared to the membrane filtration technique. Similarly, the positive predictive value was 100% against both techniques, but the negative predictive values were 99.5% against the finger prick thick blood smear and 88.3% compared to the membrane filtration technique. The test's lower sensitivity compared to the filtration technique requires further investigation.