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1.
BJA Educ ; 24(2): 57-67, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38304069
2.
Br J Pain ; 16(6): 632-640, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36452125

RESUMEN

Single-shot spinal diamorphine is becoming common practice in urological surgery to aid post-operative pain; however, its safety and efficacy require investigation. This study is a retrospective analysis of 113 laparoscopic or robotic-assisted nephrectomies over 4 years under one consultant urologist. Data were collected on demographic, pre-operative scores, anaesthesia, surgical information, post-operative outcomes and opioid consumption. Two main groups were established: no spinal diamorphine (NSD) and spinal diamorphine (SD). Four subgroups were then created, separating those who received patient-controlled anaesthesia (PCA) or not: Group 1 [general anaesthetic (GA)]; Group 2 [GA and PCA]; Group 3 [GA and spinal diamorphine] and Group 4 [GA, spinal diamorphine and PCA]. Ninety-eight eligible patients were identified. At 6 hours, pain scores were significantly higher for all non-spinal groups (p < 0.05); at 9 h, pain scores were significantly higher in NSD patients compared to SD (p = 0.026); at 12 h, pain scores were significantly higher for NSD patients compared to SD (p = 0.024), and Group 1 compared to Group 3 (p = 0.023). Total opioid consumption in the first 24 h post-surgery was higher in Group 1 compared to Group 3 (p = 0.024). There was no higher incidence of urinary retention, or any neurological complications reported within the SD patients. The study found a reduction in post-operative pain scores with the use of spinal diamorphine prior to laparoscopic and robotic-assisted nephrectomies. The findings may also suggest that pre-operative spinal diamorphine use can reduce the total volume of opioids administered via other routes in the first 24 h post-operatively. It recommends its routine administration but encourages prospective investigation.

3.
Dev Cogn Neurosci ; 57: 101144, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-35987133

RESUMEN

This paper responds to a recent critique by Bissett et al. of the fMRI Stop task used in the Adolescent Brain Cognitive Development℠ Study (ABCD Study®). The critique focuses primarily on a task design feature related to race model assumptions (i.e., that the Go and Stop processes are fully independent). In response, we note that the race model is quite robust against violations of its assumptions. Most importantly, while Bissett raises conceptual concerns with the task we focus here on analyzes of the task data and conclude that the concerns appear to have minimal impact on the neuroimaging data (the validity of which do not rely on race model assumptions) and have far less of an impact on the performance data than the critique suggests. We note that Bissett did not apply any performance-based exclusions to the data they analyzed, a number of the trial coding errors they flagged were already identified and corrected in ABCD annual data releases, a number of their secondary concerns reflect sensible design decisions and, indeed, their own computational modeling of the ABCD Stop task suggests the problems they identify have just a modest impact on the rank ordering of individual differences in subject performance.

4.
Clin Exp Immunol ; 209(2): 188-200, 2022 08 19.
Artículo en Inglés | MEDLINE | ID: mdl-35802786

RESUMEN

Group B Streptococcus (GBS) is a leading cause of adverse pregnancy outcomes due to invasive infection. This study investigated longitudinal variation in GBS rectovaginal colonization, serum and vaginal GBS capsular polysaccharide (CPS)-specific antibody levels. Non-pregnant women were recruited in the UK and were sampled every 2 weeks over a 12-week period. GBS isolates were taken from recto-vaginal swabs and serotyped by polymerase chain reaction. Serum and vaginal immunoglobulin G (IgG) and nasal immunoglobulin A (IgA) specific to CPS were measured by Luminex, and total IgG/A by ELISA. Seventy women were enrolled, of median age 26. Out of the 66 participants who completed at least three visits: 14/47 (29.8%) women that were GBS negative at screening became positive in follow-up visits and 16/19 (84.2%) women who were GBS positive at screening became negative. There was 50% probability of becoming negative 36 days after the first positive swab. The rate of detectable GBS carriage fluctuated over time, although serum, vaginal, and nasal CPS-specific antibody levels remained constant. Levels of CPS-specific antibodies were higher in the serum of individuals colonized with GBS than in non-colonized, but similar in the vaginal and nasal mucosa. We found correlations between antibody levels in serum and the vaginal and nasal mucosa. Our study demonstrates the feasibility of elution methods to retrieve vaginal and nasal antibodies, and the optimization of immunoassays to measure GBS-CPS-specific antibodies. The difference between the dynamics of colonization and antibody response is interesting and further investigation is required for vaccine development.


Asunto(s)
Complicaciones Infecciosas del Embarazo , Infecciones Estreptocócicas , Adulto , Anticuerpos Antibacterianos , Femenino , Humanos , Inmunoglobulina A , Inmunoglobulina G , Masculino , Polisacáridos , Embarazo , Infecciones Estreptocócicas/diagnóstico , Streptococcus agalactiae
5.
Anaesthesia ; 76(3): 357-365, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-32851648

RESUMEN

Our study investigated whether pre-operative screening and treatment for anaemia and suboptimal iron stores in a patient blood management clinic is cost effective. We used outcome data from a retrospective cohort study comparing colorectal surgery patients admitted pre- and post-implementation of a pre-operative screening programme. We applied propensity score weighting techniques with multivariable regression models to adjust for differences in baseline characteristics between groups. Episode-level hospitalisation costs were sourced from the health service clinical costing data system; the economic evaluation was conducted from a Western Australia Health System perspective. The primary outcome measure was the incremental cost per unit of red cell transfusion avoided. We compared 441 patients screened in the pre-operative anaemia programme with 239 patients not screened; of the patients screened, 180 (40.8%) received intravenous iron for anaemia and suboptimal iron stores. The estimated mean cost of screening and treating pre-operative anaemia was AU$332 (£183; US$231; €204) per screened patient. In the propensity score weighted analysis, screened patients were transfused 52% less red cell units when compared with those not screened (rate ratio = 0.48, 95%CI 0.36-0.63, p < 0.001). The mean difference in total screening, treatment and hospitalisation cost between groups was AU$3776 lower in the group screened (£2080; US$2629; €2325) (95%CI AU$1604-5947, p < 0.001). Screening elective patients pre-operatively for anaemia and suboptimal iron stores reduced the number of red cell units transfused. It also resulted in lower total costs than not screening patients, thus demonstrating cost effectiveness.


Asunto(s)
Anemia/diagnóstico , Anemia/terapia , Cirugía Colorrectal/economía , Análisis Costo-Beneficio/métodos , Hierro/sangre , Cuidados Preoperatorios/métodos , Anemia/economía , Estudios de Cohortes , Análisis Costo-Beneficio/economía , Análisis Costo-Beneficio/estadística & datos numéricos , Procedimientos Quirúrgicos Electivos/economía , Transfusión de Eritrocitos/economía , Femenino , Costos de la Atención en Salud/estadística & datos numéricos , Humanos , Hierro/economía , Masculino , Persona de Mediana Edad , Cuidados Preoperatorios/economía , Estudios Retrospectivos , Australia Occidental
6.
AJNR Am J Neuroradiol ; 40(4): 648-651, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-30679221

RESUMEN

On the basis of animal models, glymphatic flow disruption is hypothesized to be a factor in the development of Alzheimer's disease. We report the first quantitative study of glymphatic flow in man, combining intrathecal administration of gadobutrol with serial T1 mapping to produce contrast concentration maps up to 3 days postinjection, demonstrating performing a quantitative study using the techniques described feasibility and providing data on pharmacokinetics.


Asunto(s)
Sistema Glinfático/diagnóstico por imagen , Imagen por Resonancia Magnética/métodos , Neuroimagen/métodos , Encéfalo , Medios de Contraste/administración & dosificación , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Inyecciones Espinales , Masculino , Persona de Mediana Edad , Compuestos Organometálicos/administración & dosificación
7.
J Dev Orig Health Dis ; 10(1): 108-114, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-30626455

RESUMEN

The preconception, pregnancy and immediate postpartum and newborn periods are times for mothers and their offspring when they are especially vulnerable to major stressors - those that are sudden and unexpected and those that are chronic. Their adverse effects can transcend generations. Stressors can include natural disasters or political stressors such as conflict and/or migration. Considerable evidence has accumulated demonstrating the adverse effects of natural disasters on pregnancy outcomes and developmental trajectories. However, beyond tracking outcomes, the time has arrived for gathering more information related to identifying mechanisms, predicting risk and developing stress-reducing and resilience-building interventions to improve outcomes. Further, we need to learn how to encapsulate both the quantitative and qualitative information available and share it with communities and authorities to mitigate the adverse developmental effects of future disasters, conflicts and migrations. This article briefly reviews prenatal maternal stress and identifies three contemporary situations (wildfire in Fort McMurray, Alberta, Canada; hurricane Harvey in Houston, USA and transgenerational and migrant stress in Pforzheim, Germany) where current studies are being established by Canadian investigators to test an intervention. The experiences from these efforts are related along with attempts to involve communities in the studies and share the new knowledge to plan for future disasters or tragedies.


Asunto(s)
Salud Materna , Efectos Tardíos de la Exposición Prenatal , Estrés Psicológico/terapia , Escritura , Adolescente , Adulto , Canadá , Tormentas Ciclónicas , Desastres , Femenino , Migración Humana , Humanos , Persona de Mediana Edad , Embarazo , Resultado del Embarazo , Estrés Psicológico/complicaciones , Incendios Forestales
8.
Am J Physiol Endocrinol Metab ; 316(1): E16-E33, 2019 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-30153063

RESUMEN

Polycystic ovary syndrome (PCOS) is highly associated with cardiometabolic risk and the metabolic syndrome (MetS), predisposing women to increased risk of developing type 2 diabetes and cardiovascular disease. Metformin is commonly used to treat insulin resistance-glucose intolerance, and flutamide, an androgen receptor (AR) antagonist, is used to target hyperandrogenemia and dyslipidemia. Currently, the physiological mechanism of action of these treatments on androgen, lipidogenic, and insulin signaling pathways remains unclear in PCOS. The aim of this study was to investigate the effects and mechanisms of action of metformin and flutamide on plasma lipid-apolipoprotein (Apo)B-lipoprotein and insulin-glucose metabolism, and endocrine-reproductive indices in a PCOS-prone MetS rodent model. PCOS-prone rodents were treated with metformin (300 mg/kg body wt), flutamide (30 mg/kg body wt), or metformin + flutamide combination treatment for 6 wk. Metformin was shown to improve fasting insulin and HOMA-IR, whereas flutamide and combination treatment were shown to reduce plasma triglycerides, ApoB48, and ApoB100, and this was associated with decreased intestinal secretion of ApoB48/triglyceride. Flutamide and metformin were shown to reduce plasma androgen indices and to improve ovarian primary and preovulatory follicle frequency. Metformin treatment increased hepatic estrogen receptor (ER)α, and metformin-flutamide decreased intestinal AR and increased ERα mRNA expression. Metformin-flutamide treatment upregulated hepatic and intestinal insulin signaling, including insulin receptor, MAPK1, and AKT2. In conclusion, cardiometabolic risk factors, in particular ApoB-hypertriglyceridemia, are independently modulated via the AR, and understanding the contribution of AR and insulin-signaling pathways further may facilitate the development of targeted interventions in high-risk women with PCOS and MetS.


Asunto(s)
Antagonistas de Andrógenos/farmacología , Glucemia/efectos de los fármacos , Receptor alfa de Estrógeno/efectos de los fármacos , Flutamida/farmacología , Hipoglucemiantes/farmacología , Insulina/metabolismo , Síndrome Metabólico/metabolismo , Metformina/farmacología , Animales , Apolipoproteína B-100/efectos de los fármacos , Apolipoproteína B-100/metabolismo , Apolipoproteína B-48/efectos de los fármacos , Apolipoproteína B-48/metabolismo , Apolipoproteínas B/efectos de los fármacos , Apolipoproteínas B/metabolismo , Glucemia/metabolismo , Enfermedades Cardiovasculares , Modelos Animales de Enfermedad , Receptor alfa de Estrógeno/genética , Femenino , Fase Folicular , Resistencia a la Insulina , Mucosa Intestinal/metabolismo , Hígado/efectos de los fármacos , Hígado/metabolismo , Proteína Quinasa 1 Activada por Mitógenos/efectos de los fármacos , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Folículo Ovárico/efectos de los fármacos , Ovario/efectos de los fármacos , Síndrome del Ovario Poliquístico/metabolismo , Proteínas Proto-Oncogénicas c-akt/efectos de los fármacos , Proteínas Proto-Oncogénicas c-akt/metabolismo , ARN Mensajero , Ratas , Receptor de Insulina/efectos de los fármacos , Receptor de Insulina/metabolismo , Riesgo , Triglicéridos/metabolismo
9.
AJNR Am J Neuroradiol ; 39(10): 1806-1813, 2018 10.
Artículo en Inglés | MEDLINE | ID: mdl-30213803

RESUMEN

BACKGROUND AND PURPOSE: The central vein sign is a promising MR imaging diagnostic biomarker for multiple sclerosis. Recent studies have demonstrated that patients with MS have higher proportions of white matter lesions with the central vein sign compared with those with diseases that mimic MS on MR imaging. However, the clinical application of the central vein sign as a biomarker is limited by interrater differences in the adjudication of the central vein sign as well as the time burden required for the determination of the central vein sign for each lesion in a patient's full MR imaging scan. In this study, we present an automated technique for the detection of the central vein sign in white matter lesions. MATERIALS AND METHODS: Using multimodal MR imaging, the proposed method derives a central vein sign probability, πij, for each lesion, as well as a patient-level central vein sign biomarker, ψi. The method is probabilistic in nature, allows site-specific lesion segmentation methods, and is potentially robust to intersite variability. The proposed algorithm was tested on imaging acquired at the University of Vermont in 16 participants who have MS and 15 participants who do not. RESULTS: By means of the proposed automated technique, participants with MS were found to have significantly higher values of ψ than those without MS (ψMS = 0.55 ± 0.18; ψnon-MS = 0.31 ± 0.12; P < .001). The algorithm was also found to show strong discriminative ability between patients with and without MS, with an area under the curve of 0.88. CONCLUSIONS: The current study presents the first fully automated method for detecting the central vein sign in white matter lesions and demonstrates promising performance in a sample of patients with and without MS.


Asunto(s)
Algoritmos , Esclerosis Múltiple/diagnóstico por imagen , Neuroimagen/métodos , Venas/diagnóstico por imagen , Sustancia Blanca/diagnóstico por imagen , Adulto , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Persona de Mediana Edad , Esclerosis Múltiple/patología , Venas/patología , Sustancia Blanca/patología
11.
QJM ; 111(1): 39-45, 2018 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-29340693

RESUMEN

BACKGROUND: People with granulomatosis with polyangiitis (GPA) commonly described long delays before diagnosis. AIM: To study the natural history of GPA prior to diagnosis using primary care data, and determine whether clinical features could be identified to help earlier diagnosis. DESIGN: Case-control study using the Clinical Practice Research Datalink. METHODS: We compared primary care activity and clinical features between cases and 10 matched controls. RESULTS: We identified 757 cases and matched 7546 controls. Compared to controls, cases had more GP consultations and overall healthcare activity in the 5 years prior to their diagnosis, with a marked increase in the year before diagnosis, and particularly in the last 3 months. However, consultations were mostly for symptoms that were not specifically related to GPA. In the year prior to diagnosis, the most frequent and strongly predictive clinical features of GPA were Ear Nose and Throat (ENT) symptoms [34.5% of cases, odds ratio (OR) 10.5, 95% confidence intervals (CI) 8.6-12.7], and general (constitutional) symptoms (21.5% of cases, OR 9.0, 95% CI 7.1-11.3). In the year before diagnosis a larger number of cases attended secondary care (382, 50.5%) than had records of clinical features of GPA. CONCLUSIONS: After discussing our findings, we conclude that it would be difficult to identify cases of GPA earlier in primary care. Our results support a need for heightened awareness of this condition among secondary care clinicians, especially those assessing emergency admissions, and in the clinics which were most frequently attended by cases 3-12 months prior to diagnosis.


Asunto(s)
Granulomatosis con Poliangitis/diagnóstico , Granulomatosis con Poliangitis/fisiopatología , Atención Primaria de Salud/estadística & datos numéricos , Atención Secundaria de Salud/estadística & datos numéricos , Anciano , Estudios de Casos y Controles , Diagnóstico Precoz , Femenino , Humanos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Reino Unido
12.
Psychopharmacology (Berl) ; 235(2): 547-550, 2018 02.
Artículo en Inglés | MEDLINE | ID: mdl-28795211

RESUMEN

Psychedelic drugs are creating ripples in psychiatry as evidence accumulates of their therapeutic potential. An important question remains unresolved however: how are psychedelics effective? We propose that a sense of connectedness is key, provide some preliminary evidence to support this, and suggest a roadmap for testing it further.


Asunto(s)
Alucinógenos , Psiquiatría
13.
Psychopharmacology (Berl) ; 235(2): 399-408, 2018 02.
Artículo en Inglés | MEDLINE | ID: mdl-29119217

RESUMEN

RATIONALE: Recent clinical trials are reporting marked improvements in mental health outcomes with psychedelic drug-assisted psychotherapy. OBJECTIVES: Here, we report on safety and efficacy outcomes for up to 6 months in an open-label trial of psilocybin for treatment-resistant depression. METHODS: Twenty patients (six females) with (mostly) severe, unipolar, treatment-resistant major depression received two oral doses of psilocybin (10 and 25 mg, 7 days apart) in a supportive setting. Depressive symptoms were assessed from 1 week to 6 months post-treatment, with the self-rated QIDS-SR16 as the primary outcome measure. RESULTS: Treatment was generally well tolerated. Relative to baseline, marked reductions in depressive symptoms were observed for the first 5 weeks post-treatment (Cohen's d = 2.2 at week 1 and 2.3 at week 5, both p < 0.001); nine and four patients met the criteria for response and remission at week 5. Results remained positive at 3 and 6 months (Cohen's d = 1.5 and 1.4, respectively, both p < 0.001). No patients sought conventional antidepressant treatment within 5 weeks of psilocybin. Reductions in depressive symptoms at 5 weeks were predicted by the quality of the acute psychedelic experience. CONCLUSIONS: Although limited conclusions can be drawn about treatment efficacy from open-label trials, tolerability was good, effect sizes large and symptom improvements appeared rapidly after just two psilocybin treatment sessions and remained significant 6 months post-treatment in a treatment-resistant cohort. Psilocybin represents a promising paradigm for unresponsive depression that warrants further research in double-blind randomised control trials.


Asunto(s)
Antidepresivos/uso terapéutico , Trastorno Depresivo Resistente al Tratamiento/tratamiento farmacológico , Trastorno Depresivo Resistente al Tratamiento/psicología , Alucinógenos/uso terapéutico , Psilocibina/uso terapéutico , Sistemas de Apoyo Psicosocial , Adulto , Terapia Combinada , Trastorno Depresivo Resistente al Tratamiento/diagnóstico , Método Doble Ciego , Estudios de Factibilidad , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Factores de Tiempo , Resultado del Tratamiento
15.
CPT Pharmacometrics Syst Pharmacol ; 5(5): 283-91, 2016 05.
Artículo en Inglés | MEDLINE | ID: mdl-27299941

RESUMEN

Anti-transferrin receptor (TfR)-based bispecific antibodies have shown promise for boosting antibody uptake in the brain. Nevertheless, there are limited data on the molecular properties, including affinity required for successful development of TfR-based therapeutics. A complex nonmonotonic relationship exists between affinity of the anti-TfR arm and brain uptake at therapeutically relevant doses. However, the quantitative nature of this relationship and its translatability to humans is heretofore unexplored. Therefore, we developed a mechanistic pharmacokinetic-pharmacodynamic (PK-PD) model for bispecific anti-TfR/BACE1 antibodies that accounts for antibody-TfR interactions at the blood-brain barrier (BBB) as well as the pharmacodynamic (PD) effect of anti-BACE1 arm. The calibrated model correctly predicted the optimal anti-TfR affinity required to maximize brain exposure of therapeutic antibodies in the cynomolgus monkey and was scaled to predict the optimal affinity of anti-TfR bispecifics in humans. Thus, this model provides a framework for testing critical translational predictions for anti-TfR bispecific antibodies, including choice of candidate molecule for clinical development.


Asunto(s)
Anticuerpos Biespecíficos/administración & dosificación , Encéfalo/efectos de los fármacos , Sistemas de Liberación de Medicamentos/métodos , Diseño de Fármacos , Receptores de Transferrina/antagonistas & inhibidores , Animales , Anticuerpos Biespecíficos/química , Anticuerpos Biespecíficos/metabolismo , Barrera Hematoencefálica/efectos de los fármacos , Barrera Hematoencefálica/metabolismo , Encéfalo/metabolismo , Humanos , Macaca fascicularis , Estudios Prospectivos , Receptores de Transferrina/metabolismo
16.
Ann Rheum Dis ; 75(9): 1583-94, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27338776

RESUMEN

In this article, the 2009 European League Against Rheumatism (EULAR) recommendations for the management of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) have been updated. The 2009 recommendations were on the management of primary small and medium vessel vasculitis. The 2015 update has been developed by an international task force representing EULAR, the European Renal Association and the European Vasculitis Society (EUVAS). The recommendations are based upon evidence from systematic literature reviews, as well as expert opinion where appropriate. The evidence presented was discussed and summarised by the experts in the course of a consensus-finding and voting process. Levels of evidence and grades of recommendations were derived and levels of agreement (strengths of recommendations) determined. In addition to the voting by the task force members, the relevance of the recommendations was assessed by an online voting survey among members of EUVAS. Fifteen recommendations were developed, covering general aspects, such as attaining remission and the need for shared decision making between clinicians and patients. More specific items relate to starting immunosuppressive therapy in combination with glucocorticoids to induce remission, followed by a period of remission maintenance; for remission induction in life-threatening or organ-threatening AAV, cyclophosphamide and rituximab are considered to have similar efficacy; plasma exchange which is recommended, where licensed, in the setting of rapidly progressive renal failure or severe diffuse pulmonary haemorrhage. These recommendations are intended for use by healthcare professionals, doctors in specialist training, medical students, pharmaceutical industries and drug regulatory organisations.


Asunto(s)
Vasculitis Asociada a Anticuerpos Citoplasmáticos Antineutrófilos/tratamiento farmacológico , Manejo de la Enfermedad , Inmunosupresores/uso terapéutico , Vasculitis Asociada a Anticuerpos Citoplasmáticos Antineutrófilos/patología , Biopsia/normas , Humanos , Intercambio Plasmático , Recurrencia , Inducción de Remisión/métodos , Retratamiento/métodos
17.
Int J Paleopathol ; 12: 1-10, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29539515

RESUMEN

Adolescence is a unique period in human development encompassing sexual maturation (puberty) and the physical and psychological transition into adulthood. It is a crucial time for healthy development and any adverse environmental conditions, poor nutrition, or chronic infection can alter the timing of these physical changes; delaying menarche in girls or the age of peak height velocity in boys. This study explores the impact of chronic illness on the tempo of puberty in 607 adolescent skeletons from medieval England (AD 900-1550). A total of 135 (22.2%) adolescents showed some delay in their pubertal development, and this lag increased with age. Of those with a chronic condition, 40.0% (n=24/60) showed delay compared to only 20.3% (n=111/547) of the non-pathology group. This difference was statistically significant. A binary logistic regression model demonstrated a significant association between increasing delay in pubertal stage attainment with age in the pathology group. This is the first time that chronic conditions have been directly associated with a delay in maturation in the osteological record, using a new method to assess stages of puberty in skeletal remains.

18.
Opt Express ; 23(24): 31206-15, 2015 Nov 30.
Artículo en Inglés | MEDLINE | ID: mdl-26698749

RESUMEN

We demonstrate a compact, robust, and stable terahertz source based on a novel two section digital distributed feedback laser diode and plasmonic photomixer. Terahertz wave generation is achieved through difference frequency generation by pumping the plasmonic photomixer with two output optical beams of the two section digital distributed feedback laser diode. The laser is designed to offer an adjustable terahertz frequency difference between the emitted wavelengths by varying the applied currents to the laser sections. The plasmonic photomixer is comprised of an ultrafast photoconductor with plasmonic contact electrodes integrated with a logarithmic spiral antenna. We demonstrate terahertz wave generation with 0.15-3 THz frequency tunability, 2 MHz linewidth, and less than 5 MHz frequency stability over 1 minute, at useful power levels for practical imaging and sensing applications.


Asunto(s)
Láseres de Semiconductores , Iluminación/instrumentación , Dispositivos Ópticos , Refractometría/instrumentación , Resonancia por Plasmón de Superficie/instrumentación , Imágen por Terahertz/instrumentación , Diseño de Equipo , Análisis de Falla de Equipo , Radiación Terahertz
19.
Acta Anaesthesiol Scand ; 59(4): 434-40, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25684372

RESUMEN

BACKGROUND: Laparoscopic surgery causes specific post-operative discomfort and intraoperative cardiovascular, pulmonary, and splanchnic changes. The CO2 pneumoperitoneum-related intra-abdominal pressure (IAP) remains one of the main drivers of these changes. We investigated the influence of deep neuromuscular blockade (NMB) on IAP and surgical conditions. METHODS: This is an open prospective single-subject design study in 20 patients (14 female/6 male) undergoing laparoscopic cholecystectomy. Inclusion criteria were 18 years or older, and American Society of Anesthesiologists classification 1 to 3. Under a standardised anaesthesia, lowest IAP providing adequate surgical conditions was assessed without NMB and with deep NMB [post-tetanic count (PTC)<2] with rocuronium. The differences between IAP allowing for an adequate surgical field before and after administration of rocuronium were determined, as were effects of patient gender, age, and body mass index. RESULTS: Mean IAP without NMB was 12.75 (standard deviation 4.49) mmHg. Immediately after achieving a deep NMB, this was 7.20 (2.51). This pressure difference of 5.55 mmHg (5.08, P<0.001) dropped to 3.00 mmHg (4.30, P<0.01) after 15 min. Higher IAP differences were found in women compared with men. A modest inverse relationship was found between pressure difference and age. CONCLUSIONS: We found an almost 25% lower IAP after a deep NMB compared with no block in laparoscopic cholecystectomy. Younger and female patients appear to benefit more from deep neuromuscular blockade to reduce IAP.


Asunto(s)
Colecistectomía Laparoscópica/métodos , Bloqueo Neuromuscular/métodos , Abdomen , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Androstanoles , Femenino , Humanos , Masculino , Persona de Mediana Edad , Fármacos Neuromusculares no Despolarizantes , Presión , Estudios Prospectivos , Rocuronio , Adulto Joven
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