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1.
Br J Surg ; 108(9): 1090-1096, 2021 09 27.
Artículo en Inglés | MEDLINE | ID: mdl-33975337

RESUMEN

BACKGROUND: Data on the long-term symptom burden in patients surviving oesophageal cancer surgery are scarce. The aim of this study was to identify the most prevalent symptoms and their interactions with health-related quality of life. METHODS: This was a cross-sectional cohort study of patients who underwent oesophageal cancer surgery in 20 European centres between 2010 and 2016. Patients had to be disease-free for at least 1 year. They were asked to complete a 28-symptom questionnaire at a single time point, at least 1 year after surgery. Principal component analysis was used to assess for clustering and association of symptoms. Risk factors associated with the development of severe symptoms were identified by multivariable logistic regression models. RESULTS: Of 1081 invited patients, 876 (81.0 per cent) responded. Symptoms in the preceding 6 months associated with previous surgery were experienced by 586 patients (66.9 per cent). The most common severe symptoms included reduced energy or activity tolerance (30.7 per cent), feeling of early fullness after eating (30.0 per cent), tiredness (28.7 per cent), and heartburn/acid or bile regurgitation (19.6 per cent). Clustering analysis showed that symptoms clustered into six domains: lethargy, musculoskeletal pain, dumping, lower gastrointestinal symptoms, regurgitation/reflux, and swallowing/conduit problems; the latter two were the most closely associated. Surgical approach, neoadjuvant therapy, patient age, and sex were factors associated with severe symptoms. CONCLUSION: A long-term symptom burden is common after oesophageal cancer surgery.


Asunto(s)
Neoplasias Esofágicas/cirugía , Esofagectomía/métodos , Medición de Resultados Informados por el Paciente , Complicaciones Posoperatorias/epidemiología , Anciano , Estudios Transversales , Europa (Continente)/epidemiología , Femenino , Estudios de Seguimiento , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Calidad de Vida , Estudios Retrospectivos , Factores de Tiempo , Resultado del Tratamiento
2.
Dis Esophagus ; 34(7)2021 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-32944747

RESUMEN

Esophagectomy causes postprandial symptoms associated with an exaggerated postprandial gut hormone response. This study aimed to compare the gastrointestinal transit time of patients 1 year after esophagectomy with unoperated controls, including its relation to satiety gut hormone release. In this cross-sectional study, consecutive, disease-free patients after esophagectomy with pyloroplasty were compared with unoperated control subjects to assess gastric emptying (GE) and cecal arrival time (CAT). Serial plasma samples were collected before, and for 300 minutes after, a mixed-meal challenge. Body composition was assessed, and symptom scores were calculated. Eleven patients 1 year post-esophagectomy (age: 62.6 ± 9.8, male: 82%) did not show a significantly different GE pattern compared with 10 control subjects (P = 0.245). Rather, patients could be categorized bimodally as exhibiting either rapid or slow GE relative to controls. Those with rapid GE trended toward a higher postprandial symptom burden (P = 0.084) without higher postprandial glucagon-like peptide-1 (GLP-1) secretion (P = 0.931). CAT was significantly shorter after esophagectomy (P = 0.043) but was not significantly associated with GE, GLP-1 secretion, or symptom burden. Neither early nutrient delivery to the proximal small intestine nor to the colon explains the exaggerated postprandial GLP-1 response after esophagectomy. GE varies significantly in these patients despite consistent pyloric management.


Asunto(s)
Esofagectomía , Vaciamiento Gástrico , Estudios Transversales , Péptido 1 Similar al Glucagón , Humanos , Masculino , Periodo Posprandial
3.
Br J Surg ; 106(6): 735-746, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-30883706

RESUMEN

BACKGROUND: Oesophagectomy is associated with reduced appetite, weight loss and postprandial hypoglycaemia, the pathophysiological basis of which remains largely unexplored. This study aimed to investigate changes in enteroendocrine function after oesophagectomy. METHODS: In this prospective study, 12 consecutive patients undergoing oesophagectomy were studied before and 10 days, 6, 12 and 52 weeks after surgery. Serial plasma total fasting ghrelin, and glucagon-like peptide 1 (GLP-1), insulin and glucose release following a standard 400-kcal mixed-meal stimulus were determined. CT body composition and anthropometry were assessed, and symptom scores calculated using European Organisation for Research and Treatment of Cancer (EORTC) questionnaires. RESULTS: At 1 year, two of the 12 patients exhibited postprandial hypoglycaemia, with reductions in bodyweight (mean(s.e.m.) 17·1(3·2) per cent, P < 0·001), fat mass (21.5(2.5) kg versus 25.5(2.4) kg before surgery; P = 0·014), lean body mass (51.5(2.2) versus 54.0(1.8) kg respectively; P = 0·003) and insulin resistance (HOMA-IR: 0.84(0.17) versus 1.16(0.20); P = 0·022). Mean(s.e.m.) fasting ghrelin levels decreased from postoperative day 10, but had recovered by 1 year (preoperative: 621·5(71·7) pg/ml; 10 days: 415·1(59·80) pg/ml; 6 weeks: 309·0(42·0) pg/ml; 12 weeks: 415·8(52·1) pg/ml; 52 weeks: 547·4(83·2) pg/ml; P < 0·001) and did not predict weight loss (P = 0·198). Postprandial insulin increased progressively at 10 days, 6, 12 and 52 weeks (mean(s.e.m.) insulin AUC0-30 min : fold change 1·7(0·4), 2·0(0·4), 3·5(0·7) and 4·0(0·8) respectively; P = 0·001). Postprandial GLP-1 concentration increased from day 10 after surgery (P < 0·001), with a 3·3(1·8)-fold increase at 1 year (P < 0·001). Peak GLP-1 level was inversely associated with the postprandial glucose nadir (P = 0·041) and symptomatic neuroglycopenia (Sigstad score, P = 0·017, R2 = 0·45). GLP-1 AUC predicted loss of weight (P = 0·008, R2 = 0·52) and fat mass (P = 0·010, R2 = 0·64) at 1 year. CONCLUSION: Altered enteroendocrine physiology is associated with early satiety, weight loss and postprandial hypoglycaemia after oesophagectomy.


Asunto(s)
Esofagectomía , Hormonas Gastrointestinales/sangre , Hipoglucemia/etiología , Complicaciones Posoperatorias/etiología , Adulto , Anciano , Biomarcadores/sangre , Glucemia/metabolismo , Composición Corporal , Femenino , Estudios de Seguimiento , Ghrelina/sangre , Péptido 1 Similar al Glucagón/sangre , Humanos , Hipoglucemia/sangre , Hipoglucemia/diagnóstico , Hipoglucemia/fisiopatología , Insulina/sangre , Masculino , Persona de Mediana Edad , Evaluación de Resultado en la Atención de Salud , Complicaciones Posoperatorias/sangre , Complicaciones Posoperatorias/diagnóstico , Complicaciones Posoperatorias/fisiopatología , Periodo Posprandial , Estudios Prospectivos , Respuesta de Saciedad , Pérdida de Peso
4.
Br J Surg ; 106(10): 1341-1351, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-31282584

RESUMEN

BACKGROUND: It remains controversial whether neoadjuvant chemoradiation (nCRT) for oesophageal cancer influences operative morbidity, in particular pulmonary, and quality of life. This study combined clinical outcome data with systematic evaluation of pulmonary physiology to determine the impact of nCRT on pulmonary physiology and clinical outcomes in locally advanced oesophageal cancer. METHODS: Consecutive patients treated between 2010 and 2016 were included. Three-dimensional conformal radiation was standard, with a lung dose-volume histogram of V20 less than 25 per cent, and total radiation between 40 and 41·4 Gy. Forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and diffusion capacity for carbon monoxide (DLCO) were assessed at baseline and 1 month after nCRT. Radiation-induced lung injury (grade 2 or greater), comprehensive complications index (CCI) and pulmonary complications were monitored prospectively. Health-related quality of life was assessed among disease-free patients in survivorship. RESULTS: Some 228 patients were studied. Comparing pulmonary physiology values before with those after nCRT, FEV1 decreased from mean(s.d.) 96·8(17·7) to 91·5(20·4) per cent (-3·6(10·6) per cent; P < 0·001), FVC from 104·9(15·6) to 98·1(19·8) per cent (-3·2(11·9) per cent; P = 0·005) and DLCO from 97·6(20·7) to 82·2(20·4) per cent (-14·8(14·0) per cent; P < 0·001). Five patients (2·2 per cent) developed radiation-induced lung injury precluding surgical resection. Smoking (P = 0·005) and increased age (P < 0·001) independently predicted percentage change in DLCO. Carboplatin and paclitaxel with 41·4 Gy resulted in a greater DLCO decline than cisplatin and 5-fluorouracil with 40 Gy (P = 0·001). On multivariable analysis, post-treatment DLCO predicted CCI (P = 0·006), respiratory failure (P = 0·020) and reduced physical function in survivorship (P = 0·047). CONCLUSION: These data indicate that modern nCRT alters pulmonary physiology, in particular diffusion capacity, which is linked to short- and longer-term clinical consequences, highlighting a potentially modifiable index of risk.


ANTECEDENTES: El tema de si en el cáncer de esófago la quimiorradioterapia neoadyuvante (neoadjuvant chemoradiation, nCRT) repercute sobre la morbilidad postoperatoria, especialmente sobre la morbilidad pulmonar y la calidad de vida de los pacientes que sobreviven sigue siendo controvertido. Este estudio combina datos sobre resultados clínicos con una evaluación sistemática de la fisiología pulmonar para determinar el impacto de la nCRT sobre la fisiología pulmonar y los resultados clínicos en el cáncer de esófago localmente avanzado. MÉTODOS: Se incluyeron pacientes consecutivos tratados entre 2010-2016. La radioterapia conformal 3D fue la estándar, con un histograma dosis-volumen del pulmón V20 < 25% y radiación entre 40-41,4 Gy. Se evaluaron el volumen espiratorio forzado (forced expiratory volume, FEV1), la capacidad vital forzada (forced vital capacity, FVC) y la capacidad de difusión del monóxido de carbono (diffusion capacity for carbon monoxide, DLCO) al inicio y un mes tras la nCRT. La lesión pulmonar inducida por la radioterapia (EORTC grado ≥ 2), el índice de complicaciones integral (comprehensive complications index, CCI), grado de Clavien-Dindo, y complicaciones pulmonares fueron analizadas de manera prospectiva. Se evaluó la calidad de vida relacionada con la salud entre los pacientes supervivientes libres de enfermedad (EORTC QLQ-C30, OG25, OES18). RESULTADOS: Se estudiaron un total de 228 pacientes. Al comparar los valores de la fisiología pulmonar antes y después de la nCRT respectivamente, la FEV1 disminuyó de 96,8 ± 17,7% a 91,5 ± 20,4% (-3,6 ± 10,6%, P = 0,0002), la FVC de 104,9 ± 15,6 a 98,1 ± 19,8% (-3,2 ± 11,9%, P = 0,005) y la DLCO de 97,6 ± 20,7 a 82,2 ± 20,4% (-14,8 ± 14,0%, P < 0,0001). Cinco pacientes (2,2%) desarrollaron lesión pulmonar relacionada con la radioterapia impidiendo la resección quirúrgica. Los factores predictores independientes de %ΔDLCO fueron el hábito tabáquico (P = 0,005) y la edad avanzada (P < 0,001). El tratamiento con carboplatino/paclitaxel/41,4Gy determinó un mayor descenso de la DLCO en comparación con cisplatino/5-fluorouracilo/40Gy (P = 0,001). En el análisis multivariable, la DLCO tras el tratamiento fue una variable predictora de CCI (P = 0,006), fracaso respiratorio/intubación prolongada (P = 0,020) y reducción de la función física en los supervivientes (P = 0,047). CONCLUSIÓN: Estos datos indican que la moderna nCRT altera la fisiología pulmonar, especialmente la difusión pulmonar, con consecuencias clínicas a corto y largo plazo. La DLCO podría constituir un factor de riesgo potencialmente modificable.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Quimioradioterapia Adyuvante/métodos , Neoplasias Esofágicas/terapia , Calidad de Vida , Trastornos Respiratorios/etiología , Monóxido de Carbono/análisis , Carboplatino/administración & dosificación , Esofagectomía/métodos , Femenino , Volumen Espiratorio Forzado/fisiología , Humanos , Masculino , Persona de Mediana Edad , Terapia Neoadyuvante , Paclitaxel/administración & dosificación , Complicaciones Posoperatorias/etiología , Cuidados Preoperatorios/métodos , Capacidad Vital/fisiología
5.
World J Urol ; 37(3): 561-566, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30039387

RESUMEN

PURPOSE: Cranberry supplements are commonly used as a natural deterrent to urinary tract infection. However, one small study (n = 5) which showed an increase in urinary oxalate levels following cranberry supplementation has led to its use with caution among patients susceptible to nephrolithiasis. Furthermore, most commonly available cranberry tablet preparations contain vitamin C, which has been independently shown to increase urinary oxalate excretion. The aim of this study is to investigate the influence of cranberry supplementation on urinary oxalate excretion. METHODS: Fifteen participants were randomised to receive cranberry tablets alone or cranberry tablets containing vitamin C. Tablets were taken at the manufacturers recommended dosage for a period of 14 days. Participants provided a 24 h urine collection at trial entry and day 14. Urinary variables were compared to assess for changes in oxalate levels. RESULTS: The median age was 27 years (21-43). There was no difference in the 24 h urine volume pre or post commencement of cranberry tablets (1.7 vs 2 L, p = 0.07). An increase in median urinary oxalate excretion was observed in participants taking both cranberry-only tablets (0.10 mmol/day) and tablets containing vitamin C (1.15 mmol/day). CONCLUSION: Dietary supplementation with cranberry increases urinary oxalate excretion and should be avoided in patients at risk of urolithiasis.


Asunto(s)
Ácido Ascórbico/farmacología , Suplementos Dietéticos , Nefrolitiasis/orina , Oxalatos/orina , Preparaciones de Plantas/farmacología , Eliminación Renal/efectos de los fármacos , Vaccinium macrocarpon , Vitaminas/farmacología , Adulto , Femenino , Humanos , Masculino , Factores de Riesgo , Adulto Joven
6.
Int J Audiol ; 58(11): 754-760, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31195858

RESUMEN

Objective: To investigate whether British children's performance is equivalent to North American norms on the listening in spatialised noise-sentences test (LiSN-S). Design: Prospective study comparing the performance of a single British group of children to North-American norms on the LiSN-S (North American version). Study sample: The British group was composed of 46 typically developing children, aged 6-11 years 11 months, from a mainstream primary school in London. Results: No significant difference was observed between the British's group performance and the North-American norms for Low-cue, High-cue, Spatial Advantage and Total Advantage measure. The British group presented a significantly lower performance only for Talker Advantage measure (z-score: 0.35, 95% confidence interval -0.12 to -0.59). Age was significantly correlated with all unstandardised measures. Conclusion: Our results indicate that, when assessing British children, it would be appropriate to add a corrective factor of 0.35 to the z-score value obtained for the Talker Advantage in order to compare it to the North-American norms. This strategy would enable the use of LiSN-S in the UK to assess auditory stream segregation based on spatial cues.


Asunto(s)
Trastornos del Desarrollo del Lenguaje/diagnóstico , Prueba del Umbral de Recepción del Habla/estadística & datos numéricos , Niño , Señales (Psicología) , Femenino , Humanos , Lenguaje , Masculino , Ruido , Estudios Prospectivos , Valores de Referencia , Localización de Sonidos , Percepción del Habla , Prueba del Umbral de Recepción del Habla/métodos , Reino Unido , Estados Unidos
7.
Ir Med J ; 110(4): 544, 2017 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-28665083

RESUMEN

The aim of this study was to identify and analyse all articles published by Irish radiology departments in the medical literature since the year 2000. The PubMed database was searched to identify and review all articles published by radiologists based in the Republic of Ireland or Northern Ireland. Citation counts were then obtained and the top ten most cited articles were identified. There were 781 articles published during the study period. Of these, 558 (71%) were published in radiology journals and the remaining 223 (29%) were published in general medical journals. Abdominal radiology was the most represented sub-specialty (33% of all articles). There was a general trend of increased publications per year. Only 75 (9.6%) of articles were collaborative efforts by more than one radiology department. Irish radiology departments have a considerable research output and this has increased since the year 2000. More collaborative research between Irish radiology departments is encouraged.


Asunto(s)
Bibliometría , Radiología/estadística & datos numéricos , Investigación Biomédica , Humanos , Irlanda , Irlanda del Norte , Publicaciones Periódicas como Asunto/estadística & datos numéricos , PubMed
8.
J Clin Invest ; 80(5): 1238-44, 1987 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-2890654

RESUMEN

Entamoeba histolytica adheres to human colonic mucus, colonic epithelial cells, and other target cells via a galactose (Gal) or N-acetyl-D-galactosamine (GalNAc) inhibitable surface lectin. Blockade of this adherence lectin with Gal or GalNAc in vitro prevents amebic killing of target cells. We have identified and purified the adherence lectin by two methods: affinity columns derivatized with galactose monomers or galactose terminal glycoproteins, and affinity columns and immunoblots prepared with monoclonal antibodies that inhibit amebic adherence. By both methods the adherence lectin was identified as a 170-kD secreted and membrane-bound amebic protein. The surface location of the lectin was confirmed by indirect immunofluorescence. Purified lectin competitively inhibited amebic adherence to target cells by binding to receptors on the target Chinese hamster ovary cells in a Gal-inhibitable manner.


Asunto(s)
Asialoglicoproteínas , Entamoeba histolytica/fisiología , Hemaglutininas/aislamiento & purificación , Animales , Anticuerpos Monoclonales , Unión Competitiva , Adhesión Celular , Línea Celular , Cromatografía de Afinidad , Cricetinae , Electroforesis en Gel de Poliacrilamida , Técnica del Anticuerpo Fluorescente , Galactosa , Galectinas , Hemaglutininas/metabolismo , Técnicas para Inmunoenzimas , Técnicas Inmunológicas , Orosomucoide/análogos & derivados
9.
Ir J Med Sci ; 186(1): 63-67, 2017 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-27271165

RESUMEN

BACKGROUND: Breast cancer in women under 40 years of age is rare and typically presents symptomatically. The optimal imaging modality for this patient group is controversial. Most women undergo ultrasonography with/without mammography. Young women typically have dense breasts, which can obscure the features of malignancy on film mammography, however, initial studies have suggested that digital mammography may have a more accurate diagnostic performance in younger women. Ultrasound generally performs well in this age group, although it is poor at detecting carcinoma in situ (DCIS). AIMS: To evaluate the comparative diagnostic performance of ultrasonography and digital mammography in the initial diagnostic evaluation of women under 40 years of age with symptomatic breast cancer. METHODS: Retrospective review of all women under the age of 40 years managed at our symptomatic breast cancer unit from January 2009 to December 2015. RESULTS: There were 120 patients that met the inclusion criteria for this study. The sensitivity of ultrasonography and digital mammography for breast cancer in this patient group was 95.8 and 87.5 %, respectively. The patients with a false negative mammographic examination were more likely to have dense breasts (p < 0.01). Five patients had a false negative ultrasonographic examination, withal of whom were diagnosed with DCIS detected by mammography. CONCLUSION: This study demonstrates the superior sensitivity of ultrasound for breast cancer in women under the age of 40 years, however, the results show that digital mammography has an important complimentary role in the comprehensive assessment of these patients, particularly in the diagnosis of DCIS.


Asunto(s)
Neoplasias de la Mama/diagnóstico , Mamografía/métodos , Ultrasonografía Mamaria/métodos , Adulto , Mama/diagnóstico por imagen , Mama/patología , Neoplasias de la Mama/diagnóstico por imagen , Carcinoma in Situ/diagnóstico por imagen , Femenino , Humanos , Estudios Retrospectivos , Sensibilidad y Especificidad
10.
J Affect Disord ; 92(1): 125-31, 2006 May.
Artículo en Inglés | MEDLINE | ID: mdl-16469389

RESUMEN

BACKGROUND: Descriptions of aged patients with bipolar (BP) disorder have commented on cognitive impairments. However, the literature regarding cognitive test performance in this population has apparently been scant. METHOD: 1. We reviewed studies reporting cognitive performance in aged BP patients. 2. We compared the performance of elderly BP manic patients and aged community comparison subjects on the Mini-Mental State Examination (MMSE) and the Mattis Dementia Rating Scale (DRS). RESULTS: 1. Seven published studies of cognitive measures in aged BP patients were identified. They utilized different assessment methods and addressed different illness states, but they indicate impairments in these patients. 2. In our sample, the manic patients (n=70) had lower MMSE scores and DRS scores than did the comparison subjects (n=37). In these patients, cognitive scores were not significantly associated with Mania Rating Scale scores. LIMITATIONS: The patients in our study were assessed cross-sectionally, and they were treated naturalistically. CONCLUSIONS: Manic or depressed BP elders have impaired cognitive function; in some patients these impairments may persist. Research characterizing these impairments and their clinical implications is warranted.


Asunto(s)
Trastorno Bipolar/epidemiología , Trastorno Bipolar/psicología , Trastornos del Conocimiento/epidemiología , Adulto , Anciano , Trastornos del Conocimiento/diagnóstico , Humanos , Persona de Mediana Edad , Pruebas Neuropsicológicas
11.
Cardiovasc Res ; 32(1): 138-47, 1996 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-8776411

RESUMEN

OBJECTIVES: Electrical alternans and mechanical alternans are both associated with cardiac ischaemia and in the case of electrical alternans there is a strong link with serious ventricular arrhythmia. We elected to investigate the relationship between electrical and mechanical alternans in control and acutely ischaemic myocardium in the intact porcine heart to determine the nature of their interaction and in particular to determine if abnormal mechanical events play a role in arhythmogenesis as has been suggested in non-ischaemic preparations. METHODS: We used rapid atrial pacing to induce regional mechanical alternans and pulsus alternans before and then at 5-min intervals after the onset of acute ischaemia induced by a 30-min ligation of a diagonal branch of the left anterior descending artery. Regional mechanical activity is measured with epicardial tripodal strain gauges and regional electrical activity is measured using suction-based monophasic action potential electrodes. To test whether alternate stretching of ischaemic segments during pulsus alternans contributed to electrical alternans we simulated pulsus alternans by clamping the proximal aorta on alternate beats. RESULTS: In control areas there was a constant discordant relationship between peak systolic pressure during alternans and action potential duration. In contrast, the ischaemic areas showed electromechanical alternans that was most frequently concordant. Clamping the proximal aorta on alternate beats produced an electrical alternans in control areas but not in the ischaemic area. CONCLUSIONS: Pulsus alternans during acute ischaemia is associated with electrical alternans that can be out of phase in control and ischaemic areas. This could increase electrical dispersion which may be pro-arrhythmic.


Asunto(s)
Potenciales de Acción/fisiología , Arritmias Cardíacas/fisiopatología , Estimulación Cardíaca Artificial , Contracción Miocárdica/fisiología , Isquemia Miocárdica/fisiopatología , Animales , Porcinos
12.
Cardiovasc Res ; 32(1): 148-57, 1996 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-8776412

RESUMEN

AIMS: Increased sympathetic stimulation is known to be arrhythmogenic. Likewise increased loading of the myocardium can directly generate arrhythmias. The interaction between the two on the electrophysiology of the myocardium has not been investigated before. We investigated the effect of dobutamine infusion on the shortening of the monophasic action potential duration secondary to increased loading. This was investigated during steady-state pacing and during an alteration in beat-to-beat interval in the form of a restitution curve. METHODS: Pigs were anaesthetised and their hearts exposed. Monophasic action potentials and segment lengths were recorded from the anterior surface of the left ventricle. The loading of the ventricle was increased by transiently occluding the aorta. Steady-state pacing and a restitution curve were performed. Recordings were taken before and during dobutamine infusion. RESULTS: At steady state, increased loading of the heart shortened the monophasic action potential duration by a mean (+/- s.e.m.) of 4.0 (+/- 0.5) ms (P < 0.001). During dobutamine infusion this shortening of the monophasic action potential increased. Shortening of the action potential duration increased with the dose of dobutamine up to 10 micrograms/kg/min after which a plateau was reached. By comparison to control, dobutamine depressed the electrical restitution curve at short test pulse intervals did not significantly alter the plateau. Increased loading elevated the initial section of the electrical restitution curve at short test pulse intervals and depressed the plateau in both the control recordings and those taken during dobutamine infusion. Increased loading increased the amplitude of the supernormal phase of the electrical restitution curve in control recordings and those taken during dobutamine infusion. Sympathetic stimulation by dobutamine during the steady state potentiates the effect of mechanoelectric feedback on the myocardium. The effect on the restitution curve varies with test pulse interval. At short test pulse intervals the effect of sympathetic stimulation dominates with only minor antagonistic modification by increased loading. However, at longer test pulse intervals the effect of mechanoelectric feedback is equal to that of sympathetic stimulation and is synergistic with it. CONCLUSIONS: The mechanically induced changes we describe in the normal pig heart in situ are relatively small. However, they are in the right direction to possibly contribute to arrhythmia under pathological conditions where mechanical as well as electrophysiological inhomogeneity is prominent.


Asunto(s)
Potenciales de Acción/efectos de los fármacos , Arritmias Cardíacas/fisiopatología , Dobutamina/farmacología , Corazón/efectos de los fármacos , Transducción de Señal/fisiología , Animales , Estimulación Cardíaca Artificial , Retroalimentación , Femenino , Masculino , Porcinos
13.
Cardiovasc Res ; 28(4): 528-34, 1994 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-8181042

RESUMEN

OBJECTIVE: The electrophysiological events accompanying early ischaemia are important. The aim of this study was to investigate mechano-electric feedback in acute regional myocardial ischaemia in the intact heart in situ by measuring the change in action potential duration in response to increased ventricular loading imposed by transient aortic occlusion. METHODS: 11 landrace pigs were anaesthetised and their hearts exposed. A pneumatically operated blood pressure clamp was placed around the aorta. Monophasic action potentials and an index of segment motion were recorded from the epicardium in and around the ischaemic area produced by a snare placed around a coronary artery. Ventricular and systemic arterial pressures were measured. An initial aortic clamp was performed during which control recordings were taken. The coronary artery was then tied and the aorta clamped for 5-10 s every 5 min for the duration of the 30 min tie. Recordings were taken from the ischaemic area and non-ischaemic areas. RESULTS: Aortic clamp before ischaemia increased intraventricular diastolic and systolic pressure and reduced action potential duration in all the areas studied (p < 0.001). During acute regional myocardial ischaemia aortic clamping resulted in significantly more shortening of the action potential in the ischaemic area after 10 min of ischaemia than in the control area (5 ms v 10 ms, p = 0.008). Over the following 20 min the degree of shortening decreased. The greater shortening at 10 min could not be attributed to changes in the end diastolic segment length or peak ventricular pressure and could thus represent a change in the expression of mechano-electric feedback by ischaemic myocardium rather than a change in loading conditions. CONCLUSIONS: During the first 30 min following a coronary artery occlusion mechano-electric feedback in the ischaemic myocardium varies with time.


Asunto(s)
Potenciales de Acción/fisiología , Corazón/fisiopatología , Contracción Miocárdica/fisiología , Isquemia Miocárdica/fisiopatología , Animales , Arritmias Cardíacas/fisiopatología , Retroalimentación , Femenino , Masculino , Porcinos
14.
Cardiovasc Res ; 27(9): 1639-44, 1993 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-8287443

RESUMEN

OBJECTIVE: The aim was to investigate the behaviour of regional myocardium during mechanical alternans in a multidirectional manner. METHODS: Mechanical alternans was induced in 12 anaesthetised open chested pigs by rapid atrial pacing. In contrast to previous studies, regional mechanical activity was simultaneously assessed at up to three different sites on the left ventricle using epicardial measuring devices able to provide multidirectional information on segment motion. Pressure-length loops were plotted to assess different patterns of segmental motion. The integral of pressure and length was calculated to obtain a regional work index for each beat. RESULTS: Pressure-length loops revealed profound abnormalities in segment motion and work index during regional mechanical alternans. Myocardial segments either performed alternate amounts of positive work on each beat or alternate amounts of positive and negative work on each beat. Alternating segments contracted out of phase with each other and were occasionally stretched during systole. CONCLUSIONS: The spatio-temporal heterogeneity of regional mechanical behaviour is greatly increased during mechanical alternans.


Asunto(s)
Cardiopatías/fisiopatología , Corazón/fisiopatología , Anestesia General , Animales , Estimulación Cardíaca Artificial , Modelos Animales de Enfermedad , Porcinos
15.
Biol Psychiatry ; 30(7): 703-10, 1991 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-1958767

RESUMEN

Perceptual asymmetries as indicated by dichotic listening tasks have been associated with both subtype of depression and response to antidepressant treatment. To examine the association between this relatively new measure and more traditional measures of hypothalamic-pituitary-adrenal axis (HPA) activation in depression, we assessed perceptual asymmetry and basal plasma cortisol in a sample of depressed outpatients undergoing a double-blind, placebo-controlled medication trial. Each measure was examined for its ability to predict response to treatment. Perceptual asymmetry was significantly associated with plasma cortisol levels, and was also a significant predictor of treatment response. The association between plasma cortisol and treatment response did not reach significance. Our findings are limited by relatively small sample sizes but encourage further examination of perceptual asymmetry measures as predictors of treatment response and in relation to HPA activation in depression.


Asunto(s)
Atención Ambulatoria , Antidepresivos/uso terapéutico , Trastorno Depresivo/tratamiento farmacológico , Trastorno Depresivo/fisiopatología , Pruebas de Audición Dicótica , Dominancia Cerebral/efectos de los fármacos , Dominancia Cerebral/fisiología , Hidrocortisona/sangre , S-Adenosilmetionina/uso terapéutico , Percepción del Habla/efectos de los fármacos , Percepción del Habla/fisiología , Adulto , Trastorno Depresivo/psicología , Dexametasona , Método Doble Ciego , Femenino , Humanos , Sistema Hipotálamo-Hipofisario/efectos de los fármacos , Sistema Hipotálamo-Hipofisario/fisiopatología , Masculino , Sistema Hipófiso-Suprarrenal/efectos de los fármacos , Sistema Hipófiso-Suprarrenal/fisiopatología , Pronóstico
16.
Arch Neurol ; 54(6): 707-12, 1997 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-9193205

RESUMEN

OBJECTIVE: To assess the reliability and stability of a standardized road test for healthy aging people and those with dementia of the Alzheimer type (DAT). DESIGN: A prospective study involving patients with DAT and age-matched healthy controls in which subjects' driving performance was evaluated by several raters in an initial and a follow-up road test. SETTING: Urban medical school and urban highways and streets. SUBJECTS: A convenience sample of 58 controls, 36 subjects with very mild DAT, and 29 subjects with mild DAT. RESULTS: Analysis of road test ability of controls (2 subjects [3%] failed the test), very mild DAT subjects (7 subjects [19%] failed), and mild DAT subjects (12 subjects [41%] failed) disclosed a significant association between driving performance and dementia status (chi 2[4] = 20.65 [N = 123]; P < .001; Kendall tau-b = 0.306). Interrater reliability for assessment of driving performance ranged from kappa = 0.85 to 0.96. One-month test-retest stability on the road test was 0.76 (quantitative scoring) and 0.53 (clinical judgment). CONCLUSIONS: Dementia adversely affects driving performance even in its mild stages, although some persons with DAT seem to drive safely for some time after disease onset. A traffic-interactive, performance-based road test that examines cognitive behaviors provides an accurate and reliable functional assessment of driving ability.


Asunto(s)
Enfermedad de Alzheimer/fisiopatología , Enfermedad de Alzheimer/psicología , Conducción de Automóvil , Desempeño Psicomotor , Anciano , Estudios de Casos y Controles , Femenino , Humanos , Masculino , Persona de Mediana Edad , Missouri , Pruebas Neuropsicológicas , Estudios Prospectivos , Valores de Referencia , Reproducibilidad de los Resultados , Índice de Severidad de la Enfermedad
17.
Arch Clin Neuropsychol ; 13(4): 339-47, 1998 May.
Artículo en Inglés | MEDLINE | ID: mdl-14590613

RESUMEN

Previous studies have revealed working memory impairments in individuals with dementia of the Alzheimer type (DAT) using visually and auditorily presented verbal materials, and visually presented nonverbal materials. Based on findings from behavioral and neuropathological studies, impairments in working memory for auditorily presented nonverbal materials have been hypothesized as well. Results of a study conducted by Kurylo, Corkin, Allard, Zatorre, and Growden (1993), however, failed to support this hypothesis. In the current investigation, perception and working memory for nonverbal auditory information (tones) were assessed using same-different discrimination tasks. Participants included individuals with no dementia, very mild DAT, and mild DAT. Unlike the findings from the study conducted by Kurylo and colleagues, our results suggest intact tone perception but a progressive decline in working memory for auditory nonverbal information with advancing DAT. A similar decline was also noted on a task assessing working memory for auditorily presented verbal information.

18.
Braz J Med Biol Res ; 43(4): 359-66, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-20445951

RESUMEN

The objective of this study was to investigate the phenomenon of learning generalization of a specific skill of auditory temporal processing (temporal order detection) in children with dyslexia. The frequency order discrimination task was applied to children with dyslexia and its effect after training was analyzed in the same trained task and in a different task (duration order discrimination) involving the temporal order discrimination too. During study 1, one group of subjects with dyslexia (N = 12; mean age = 10.9 + or - 1.4 years) was trained and compared to a group of untrained dyslexic children (N = 28; mean age = 10.4 + or - 2.1 years). In study 2, the performance of a trained dyslexic group (N = 18; mean age = 10.1 + or - 2.1 years) was compared at three different times: 2 months before training, at the beginning of training, and at the end of training. Training was carried out for 2 months using a computer program responsible for training frequency ordering skill. In study 1, the trained group showed significant improvement after training only for frequency ordering task compared to the untrained group (P < 0.001). In study 2, the children showed improvement in the last interval in both frequency ordering (P < 0.001) and duration ordering (P = 0.01) tasks. These results showed differences regarding the presence of learning generalization of temporal order detection, since there was generalization of learning in only one of the studies. The presence of methodological differences between the studies, as well as the relationship between trained task and evaluated tasks, are discussed.


Asunto(s)
Estimulación Acústica/métodos , Percepción Auditiva/fisiología , Aprendizaje Discriminativo/fisiología , Dislexia/fisiopatología , Adolescente , Niño , Femenino , Humanos , Masculino , Índice de Severidad de la Enfermedad
20.
Braz J Med Biol Res ; 42(7): 647-54, 2009 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-19578644

RESUMEN

Studies have shown that dyslexic children present a deficiency in the temporal processing of auditory stimuli applied in rapid succession. However, discussion continues concerning the way this deficiency can be influenced by temporal variables of auditory processing tests. Therefore, the purpose of the present study was to analyze by auditory temporal processing tests the effect of temporal variables such as interstimulus intervals, stimulus duration and type of task on dyslexic children compared to a control group. Of the 60 children evaluated, 33 were dyslexic (mean age = 10.5 years) and 27 were normal controls (mean age = 10.8 years). Auditory processing tests assess the abilities of discrimination and ordering of stimuli in relation to their duration and frequency. Results showed a significant difference in the average accuracy of control and dyslexic groups considering each variable (interstimulus intervals: 47.9 +/- 5.5 vs 37.18 +/- 6.0; stimulus duration: 61.4 +/- 7.6 vs 50.9 +/- 9.0; type of task: 59.9 +/- 7.9 vs 46.5 +/- 9.0) and the dyslexic group demonstrated significantly lower performance in all situations. Moreover, there was an interactive effect between the group and the duration of stimulus variables for the frequency-pattern tests, with the dyslexic group demonstrating significantly lower results for short durations (53.4 +/- 8.2 vs 48.4 +/- 11.1), as opposed to no difference in performance for the control group (62.2 +/- 7.1 vs 60.6 +/- 7.9). These results support the hypothesis that associates dyslexia with auditory temporal processing, identifying the stimulus-duration variable as the only one that unequally influenced the performance of the two groups.


Asunto(s)
Estimulación Acústica/métodos , Trastornos de la Percepción Auditiva/etiología , Dislexia/complicaciones , Trastornos de la Percepción Auditiva/diagnóstico , Trastornos de la Percepción Auditiva/fisiopatología , Estudios de Casos y Controles , Niño , Dislexia/fisiopatología , Femenino , Humanos , Masculino , Factores de Tiempo
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