Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 62
Filtrar
1.
Curr Oncol ; 27(1): e1-e8, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-32218662

RESUMEN

Background: Pancreatic cancer (pcc) is one of the most lethal types of cancer, and surgery remains the optimal treatment modality for patients with resectable tumours. The objective of the present study was to examine and compare trends in the survival rate based on treatment modality in patients with pcc. Methods: This population-based retrospective analysis included all patients with known-stage pcc in Ontario between 2007 and 2015. Flexible parametric models were used to conduct the survival analysis. Survival rates were calculated based on treatment modality, while adjusting for patient- and tumour-specific covariates. Results: The study included 6437 patients. We found no noticeable improvement in survival for patients with stage iii or iv tumours; however, for stage i disease, the 1-, 2-, and 5-year survival rates increased over time to 81% from 51%, to 71% from 35%, and to 61% from 22% respectively. Most improvements were seen for surgical modalities, with 2-year survivals increasing to 89% from 65% for distal pancreatectomy (dp) without radiation (rt) or chemotherapy (ctx), to 65% from 37% for dp plus rt or ctx, to 60% from 44% for Whipple-only, and to 50% from 36% for Whipple plus rt or ctx. Lastly, 5-year survival improved to 81% from 52% for dp only, to 41% from 12% for dp plus rt or ctx, to 49% from 25% for Whipple-only, and to 26% from 12% for Whipple plus rt or ctx. Conclusions: Most cases of pcc continue to be diagnosed at a late stage, with poor short-term and long-term prognoses. After adjustment for patient age, sex, and year of diagnosis, the survival for stage i tumours and for surgical modalities increased over time. Further research is needed to identify the reasons for improvement in survival during the study period.


Asunto(s)
Neoplasias Pancreáticas/terapia , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neoplasias Pancreáticas/mortalidad , Estudios Retrospectivos , Análisis de Supervivencia , Neoplasias Pancreáticas
2.
Curr Oncol ; 25(5): 338-341, 2018 10.
Artículo en Inglés | MEDLINE | ID: mdl-30464683

RESUMEN

Background: Cancer research is essential in evaluating the safety and effectiveness of emerging cancer treatments, which in turn can lead to ground-breaking advancements in cancer care. Given limited research funding, allocating resources in alignment with societal burden is essential. However, evidence shows that such alignment does not typically occur. The objective of the present study was to provide an updated overview of site-specific cancer research investment in Canada and to explore potential discrepancies between the site-specific burden and the level of research investment. Methods: The 10 cancer sites with the highest mortality in 2015-which included brain, female breast, colorectal, leukemia, lung, non-Hodgkin lymphoma, ovary, pancreas, prostate, and uterus-were selected for the analysis. Information about site-specific research investment and cancer burden (raw incidence and mortality) was obtained from the Canadian Cancer Research Survey and Statistics Canada's cansim (the Canadian Socio-Economic Information Management System) respectively. The ratio of site-specific research investment to site-specific burden was used as an indicator of overfunding (ratio > 1) or underfunding (ratio < 1). Results: The 3 cancer sites with the highest research investments were leukemia, prostate, and breast, which together represented 51.3% of 2015 cancer research funding. Conversely, the 3 cancer sites with the lowest investments were uterus, pancreas, and ovary, which together represented 7.8% of 2015 research funding. Relative to site-specific cancer burden, the lung, uterus, and colorectal sites were consistently the most underfunded. Conclusions: Observed discrepancies between cancer burden and research investment indicate that some cancer sites (such as lung, colorectal, and uterus) seem to be underfunded when site-specific incidence and mortality are taken into consideration.


Asunto(s)
Investigación Biomédica/economía , Neoplasias/economía , Apoyo a la Investigación como Asunto , Canadá , Humanos , Asignación de Recursos
3.
Dis Esophagus ; 29(5): 472-8, 2016 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25809620

RESUMEN

This prospective population-based study was designed to evaluate treatment choices in patients with new manometrically diagnosed achalasia and their outcomes. Patients referred to the esophageal function laboratory were enrolled after a new manometric diagnosis of achalasia. Patients completed an initial achalasia symptom score validated questionnaire on their symptom severity, duration, treatment pre-diagnosis and Medical Outcomes Study 36-item Short-Form (SF-36) survey. Treatment decisions were made by the referring physician and the patient. Follow-up questionnaires were completed every 3 months for 1 year. Patients who chose not to undergo treatment at 1-year follow-up completed another questionnaire after 5 years. Between January 2004 and January 2005, 83 of 124 eligible patients were enrolled. Heller myotomy was performed on 31 patients, three patients received botulinum toxin injections, and 25 patients received 29 pneumatic balloon dilatations. Twenty-four patients chose to receive no treatment. Following treatment, patients treated with surgery, dilatation and botulinum toxin had an average improvement in achalasia symptom score of 23 +/- 12.2, 17 +/- 10.9, and 9 +/- 14, respectively. Patients receiving no treatment had worsening symptoms with a symptom score change of -3.5 +/- 11.4. Surgery and dilatation resulted in significant improvement (P < 0.01) relative to no treatment. In univariate logistic regression, symptom severity score (odds ratio [OR] 1.04, 95% confidence interval [CI] 1.00 to 1.08), sphincter tone (OR 1.04, 95% CI 1.00 to 1.09), difficulty swallowing liquids (OR 3.21, 95% 1.15 to 8.99), waking from sleep (OR 2.75, 95% 1.00 to 7.61), and weight loss (OR 5.99, 95% CI 1.93 to 18.58) were all significant in predicting that patients would select treatment. In the multivariate analysis, older age (OR 1.05, 95% CI 1.01 to 1.09) and weight loss (OR 3.91, 95% CI 1.02 to 15.2) were statistically significant for undergoing treatment. At 5 years, five (21%) of those who had initially declined treatment at 1 year ultimately chose a treatment. Patients who finally chose Heller myotomy had lower mental component dimension scores on the SF-36 at 1 year than those who did not. This study shows that almost one third of patients with manometrically diagnosed achalasia choose not to undergo treatment within 1 year of their diagnosis. Patients who are more symptomatic appear to be more likely to undergo treatment by univariate analysis. In multivariate analysis, increasing age and weight loss are predictive of those who will undergo treatment, with weight loss having the greatest influence. Patients who choose not to undergo treatment make lifestyle changes to maintain their quality of life, and only a minority of them ultimately undergo treatment.


Asunto(s)
Acalasia del Esófago/terapia , Prioridad del Paciente/estadística & datos numéricos , Negativa del Paciente al Tratamiento/estadística & datos numéricos , Toxinas Botulínicas/administración & dosificación , Dilatación/métodos , Dilatación/estadística & datos numéricos , Acalasia del Esófago/fisiopatología , Esofagoscopía/métodos , Esofagoscopía/estadística & datos numéricos , Femenino , Estudios de Seguimiento , Humanos , Modelos Logísticos , Masculino , Manometría , Persona de Mediana Edad , Análisis Multivariante , Neurotoxinas/administración & dosificación , Oportunidad Relativa , Estudios Prospectivos , Estudios Retrospectivos , Índice de Severidad de la Enfermedad , Encuestas y Cuestionarios , Resultado del Tratamiento
4.
Phys Rev Lett ; 104(16): 161101, 2010 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-20482038

RESUMEN

We report studies of ultrahigh-energy cosmic-ray composition via analysis of depth of air shower maximum (X(max)), for air shower events collected by the High-Resolution Fly's Eye (HiRes) observatory. The HiRes data are consistent with a constant elongation rate d/d[log(E)] of 47.9+/-6.0(stat)+/-3.2(syst) g/cm2/decade for energies between 1.6 and 63 EeV, and are consistent with a predominantly protonic composition of cosmic rays when interpreted via the QGSJET01 and QGSJET-II high-energy hadronic interaction models. These measurements constrain models in which the galactic-to-extragalactic transition is the cause of the energy spectrum ankle at 4x10(18) eV.

5.
Phys Rev Lett ; 100(10): 101101, 2008 Mar 14.
Artículo en Inglés | MEDLINE | ID: mdl-18352170

RESUMEN

The High Resolution Fly's Eye (HiRes) experiment has observed the Greisen-Zatsepin-Kuzmin suppression (called the GZK cutoff) with a statistical significance of five standard deviations. HiRes' measurement of the flux of ultrahigh energy cosmic rays shows a sharp suppression at an energy of 6 x 10(19) eV, consistent with the expected cutoff energy. We observe the ankle of the cosmic-ray energy spectrum as well, at an energy of 4 x 10(18) eV. We describe the experiment, data collection, and analysis and estimate the systematic uncertainties. The results are presented and the calculation of the statistical significance of our observation is described.

6.
Surg Endosc ; 21(12): 2178-82, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-17514394

RESUMEN

BACKGROUND: Anterior fundoplication (AF) following laparoscopic Heller myotomy (LHM) for achalasia may prevent esophageal leaks and gastroesophageal reflux but cause dysphagia. Our study attempts to determine the effect of AF on esophageal leaks, nuclear medicine esophageal clearance (EC), symptom frequency (SF), and Van Trappen symptom scores (SS) for dysphagia, regurgitation, and heartburn. METHODS: Between 1995 and 2004, pre- and postoperative (2-12 months) EC, SF, and SS scores were compared in 95 patients undergoing LHM for achalasia with AF (n = 71) and without (n = 24) AF. RESULTS: There were no leaks or deaths. Laparoscopic Heller myotomy decreased the frequency of postoperative dysphagia, regurgitation, and heartburn with AF (96% preoperation versus 6% postoperation, 94% versus 3%, 58% versus 6%) (p = 0.001) and without AF (100% versus 0%, 83% versus 0%, 50% versus 4%) (p = 0.001). Laparoscopic Heller myotomy improved all SS in both groups. There was no difference between postoperative dysphagia (1.38 +/- 0.64 versus 1.17 +/- 38) p = 0.06, regurgitation (1.17 +/- 51 versus 1.04 +/- 0.20) p = 0.08, and heartburn (1.29 +/- 62 versus 1.53 +/- 0.80) p = 0.185 scores between the AF and no-AF group, respectively. There is a trend toward improvement in dysphagia and regurgitation in the no-AF group. Laparoscopic Heller myotomy improved EC in the supine and upright positions in both groups of patients (p = 0.001). There was an improved mean change in EC (10 min upright) in the no-AF group versus the AF group (50.7% +/- 30.8 versus 29.7% +/- 30.2) p = 0.004. CONCLUSIONS: Laparoscopic Heller myotomy improves esophageal transit and the frequency and severity of dysphagia, heartburn, and regurgitation in a safe manner. Patients without AF show a statistically better upright EC with a trend toward improved dysphagia and regurgitation.


Asunto(s)
Acalasia del Esófago/fisiopatología , Acalasia del Esófago/cirugía , Esófago/fisiopatología , Fundoplicación/métodos , Laparoscopía , Adulto , Anciano , Deglución , Trastornos de Deglución/etiología , Trastornos de Deglución/fisiopatología , Trastornos de Deglución/prevención & control , Acalasia del Esófago/complicaciones , Femenino , Fundoplicación/efectos adversos , Fundoplicación/normas , Reflujo Gastroesofágico/etiología , Reflujo Gastroesofágico/fisiopatología , Reflujo Gastroesofágico/prevención & control , Pirosis/etiología , Pirosis/fisiopatología , Pirosis/prevención & control , Humanos , Masculino , Persona de Mediana Edad , Postura , Índice de Severidad de la Enfermedad
7.
Int J Obes (Lond) ; 31(2): 292-8, 2007 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-16755283

RESUMEN

OBJECTIVE: To evaluate and describe retention rates and weight loss in clients participating in a commercial weight loss program. SUBJECTS: A total of 60 164 men and women ages 18-79 years who enrolled in the Jenny Craig Platinum program between May 2001 and May 2002. METHODS: Retention rates, mean weight loss and percent weight loss were calculated on a weekly basis for the 52-week period following initial enrollment in the weight loss program. Clients were categorized based on final week of participation in the program (weeks 1-4, weeks 5-13, weeks 14-26, weeks 27-39 and weeks 40-52) and weight loss was calculated at final week. A subgroup of clients was identified based on attendance through 13, 26 and 52 weeks. Mean and percent weight loss was calculated for these subgroups of clients. RESULTS: Of the 60 164 men and women who enrolled in the weight loss program, 73% were retained in the program after 4 weeks, 42% at 13 weeks, 22% at 26 weeks and 6.6% at 52 weeks. Clients who dropped out of the program during the first 4 weeks lost 1.1+/-1.6% (mean+/-s.d.) of their initial body weight, whereas clients who dropped out between 40 and 52 weeks lost 12.0+/-7.2%. Clients in the 13-week, 26-week and 52-week cohorts lost 8.3+/-3.3, 12.6+/-5.1 and 15.6+/-7.5% of their initial body weight, respectively. CONCLUSION: Weight loss was greater among clients who were retained in the program longer. The findings from this study suggest that a commercial weight loss program can be an effective weight loss tool for individuals who remain active in the program.


Asunto(s)
Obesidad/terapia , Cooperación del Paciente , Pérdida de Peso , Adolescente , Adulto , Anciano , Peso Corporal , Comercio , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Obesidad/fisiopatología , Obesidad/psicología , Evaluación de Programas y Proyectos de Salud , Resultado del Tratamiento
9.
Surg Endosc ; 16(5): 777-80, 2002 May.
Artículo en Inglés | MEDLINE | ID: mdl-11997820

RESUMEN

BACKGROUND: Wrap disruption or intrathoracic herniation of a fundoplication is a dreaded complication of laparoscopic foregut surgery. This problem may often be related to postoperative nausea and vomiting (PONV). This study aimed to investigate the occurrence of PONV and its management in patients undergoing laparoscopic foregut procedures. METHODS: Between January 31 and May 23, 2000, 104 patients undergoing laparoscopic foregut procedures (fundoplication, myotomy, or paraesophageal hernia repair) were followed prospectively. Their postoperative course was documented along with the occurrence and management of PONV. All laparoscopic foregut surgery patients are managed postoperatively with a uniform clinical pathway, and their care is focused on a nursing unit with skill and experience in postoperative management. RESULTS: Nausea was documented in the postanesthesia care unit (PACU) for 30.1% of the patients, and for 59.6% of the patients during their nursing unit stay. Antiemetics were given to all the patients with documented nausea. Emesis was noted in 1.9% of the patients in the PACU, as compared with 3.8% of the patients on the floor. In one of the patients with nursing unit emesis, an acute wrap herniation into the chest occurred, necessitating a return to the operating room for correction. The patients with a history of postoperative nausea did not have a higher rate of PONV than in those with no history of postoperative nausea. The use of preoperative or intraoperative antiemetics did not appear to alter the occurrence of PONV. Postoperative nausea occurred in 60% of the patients administered preoperative antiemetic, as compared with 64% of the patients who received no preoperative antiemetic. The average length of hospital stay was longer in those with PONV than in those with no PONV (2.6 vs 1.8 days). CONCLUSION: Nausea after laparoscopic foregut procedures is common, occurring twice as often on the nursing unit as in the PACU. The occurrence of PONV leads to a longer hospital stay, and can result in significant sequelae requiring reoperation. The use of preoperative or intraoperative antiemetics does not alter the frequency of postoperative nausea, suggesting the need to develop effective preemptive regimens for patients undergoing laparoscopic foregut procedures. The high rate of PONV and its potential risk of damage to a fundoplication and hiatal hernia repair should lead surgeons to consider whether laparoscopic foregut procedures should ever be performed on an outpatient basis.


Asunto(s)
Fundoplicación/efectos adversos , Fundoplicación/estadística & datos numéricos , Laparoscopía/efectos adversos , Laparoscopía/estadística & datos numéricos , Náusea y Vómito Posoperatorios/epidemiología , Antieméticos/efectos adversos , Antieméticos/uso terapéutico , Índice de Masa Corporal , Unión Esofagogástrica/cirugía , Femenino , Fundoplicación/métodos , Hernia Hiatal/cirugía , Humanos , Laparoscopía/métodos , Tiempo de Internación , Masculino , Persona de Mediana Edad , Náusea y Vómito Posoperatorios/prevención & control , Náusea y Vómito Posoperatorios/terapia , Cuidados Preoperatorios/efectos adversos , Cuidados Preoperatorios/métodos , Estudios Prospectivos , Factores Sexuales
10.
Int J Obes Relat Metab Disord ; 26(6): 805-13, 2002 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12037651

RESUMEN

OBJECTIVE: To examine the relation between fitness and fibrinogen, white blood cell count, uric acid and metabolic syndrome across levels of adiposity in apparently healthy, nonsmoking men. DESIGN: Cross-sectional study of 4057 men from the Aerobics Center Longitudinal Study examining the age-adjusted resting levels and risk of having a clinically significant elevation of fibrinogen, white blood cell count, uric acid and metabolic syndrome score across nine fitness-body fatness combinations. Fitness categories (low fitness, moderately fit or high fitness) were based on a maximal treadmill test. Body mass index (BMI) <25.0 was classified as normal weight, BMI > or = 25.0 but <30.0 as overweight and BMI > or = 30.0 as obese. RESULTS: Fitness (inversely) and BMI (directly) were independently related to the age-adjusted values of all four variables (P for trend P<0.0001 for each). For all four variables, the greatest age-adjusted risk of having a clinically relevant value was found in the low fitness-obese category and the lowest age-adjusted risk was found in the high fitness-normal weight group. CONCLUSION: Fibrinogen, white blood cells, uric acid and metabolic syndrome score are independently related to both fitness (inversely) and fatness (directly). Within levels of fatness, risk for significant elevations in fibrinogen, white blood cells, uric acid and metabolic syndrome score is lower for the higher fitness groups.


Asunto(s)
Composición Corporal , Fibrinógeno/análisis , Recuento de Leucocitos , Síndrome Metabólico/fisiología , Aptitud Física , Ácido Úrico/sangre , Tejido Adiposo , Adulto , Constitución Corporal , Índice de Masa Corporal , Estudios Transversales , Humanos , Modelos Logísticos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Obesidad/fisiopatología , Oportunidad Relativa
11.
Arch Ophthalmol ; 119(9): 1254-7, 2001 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-11545629

RESUMEN

OBJECTIVE: To determine concentrations of ofloxacin and ciprofloxacin hydrochloride in aqueous humor after topical or combined topical and oral administration in eyes with filtering blebs. DESIGN: A prospective, investigator-masked, randomized, controlled comparative study involving 36 eyes of 34 patients with functioning filtering blebs who were to undergo cataract surgery. Treatment groups received either topical ofloxacin or topical ciprofloxacin (instillation of 0.3% ophthalmic solution every 30 minutes for 4 hours before surgery), or a combined topical plus oral regimen (ciprofloxacin hydrochloride, four 100-mg tablets, or ofloxacin, one 400-mg tablet, administered 24-26, 12-14, and 2 hours preceding surgery). The main outcome measure was antibiotic concentration measured by chromatographic separation and mass spectrometry of aqueous samples obtained during surgery. RESULTS: Topical antibiotic treatment yielded mean concentrations of ofloxacin, 0.75 microg/mL, and ciprofloxacin, 0.21 microg/mL, in aqueous. With combined topical and oral therapy, significantly more ofloxacin was measured than ciprofloxacin (3.84 microg/mL vs 0.35 microg/mL [P<.001]). The combination regimen produced significantly greater ofloxacin levels than did topical therapy alone (P =.007). CONCLUSIONS: Ofloxacin penetrates better than ciprofloxacin into the aqueous of eyes with filtering blebs, particularly after combined topical and oral administration, by which ofloxacin reaches more than a 10-fold greater concentration than does ciprofloxacin. Combined topical and oral therapy with ofloxacin may be beneficial in the treatment of bleb-associated infections.


Asunto(s)
Antiinfecciosos/farmacocinética , Humor Acuoso/metabolismo , Ciprofloxacina/farmacocinética , Cirugía Filtrante , Ofloxacino/farmacocinética , Administración Oral , Administración Tópica , Adulto , Anciano , Anciano de 80 o más Años , Disponibilidad Biológica , Cromatografía Líquida de Alta Presión , Quimioterapia Combinada , Femenino , Cromatografía de Gases y Espectrometría de Masas , Humanos , Masculino , Persona de Mediana Edad , Soluciones Oftálmicas , Estudios Prospectivos
12.
Surg Endosc ; 15(8): 823-6, 2001 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11443451

RESUMEN

BACKGROUND: Laparoscopic fundoplication (LF) procedures have been shown to be safe and effective for the control of gastroesophageal reflux disease (GERD). Preliminary reports suggest that LF can be performed safely in an ambulatory surgery center. We report on our extensive experience with outpatient LF. METHODS: Since May 1995, we have performed laparoscopic antireflux procedures in 557 consecutive patients at a freestanding outpatient surgery center. All patients had esophageal manometrics and esophagogastroduodenoscopy (EGD) within 1 year of their surgical procedure. This series included 16 patients with large paraesophageal hernias (mostly type III) and 22 patients with prior antireflux procedures. Most patients (n = 494) underwent Nissen fundoplication. RESULTS: Patients were typically given clear liquids 6 hs postoperatively and discharged home in


Asunto(s)
Fundoplicación/métodos , Reflujo Gastroesofágico/cirugía , Laparoscopía/métodos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Procedimientos Quirúrgicos Ambulatorios/métodos , Femenino , Fundoplicación/efectos adversos , Humanos , Laparoscopía/efectos adversos , Masculino , Persona de Mediana Edad
13.
J Community Health ; 26(1): 39-50, 2001 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-11297189

RESUMEN

The use of hormone replacement therapy (HRT) is a controversial decision for many women, yet few studies have evaluated the socio-demographic, psychological, and behavioral correlates of HRT use. This cross-sectional, mailed survey evaluated the associations of socioeconomic status, preventive health behaviors, knowledge and perceptions about HRT-related risks and benefits with HRT use among 428 women 50-70 years old in Vermont. The overall prevalence of HRT use was 40%. Women of moderate to high income were three times more likely than those of low income to use HRT. HRT use was significantly higher among women whose physician had encouraged use (58%) than among those who received ambivalent recommendations from their physicians (20%). Hysterectomy, higher income, younger age, regular adherence to cervical cancer screening, and recommendation by a provider were significantly associated with HRT use in multivariate analyses. There were no differences in HRT use according to level of concern about heart disease, osteoporosis, or breast cancer. A recommendation by a health care provider is a powerful predictor of HRT use, but disparities in use exist by socioeconomic status. Future research should examine why lower income women are less likely to use HRT and whether the discrepancy is due to inconsistent recommendations by health care providers.


Asunto(s)
Terapia de Reemplazo de Estrógeno/estadística & datos numéricos , Aceptación de la Atención de Salud/estadística & datos numéricos , Atención Primaria de Salud , Factores Socioeconómicos , Anciano , Estudios Transversales , Toma de Decisiones , Femenino , Conductas Relacionadas con la Salud , Humanos , Persona de Mediana Edad , New York , Posmenopausia , Factores de Riesgo , Encuestas y Cuestionarios , Vermont
15.
Hear Res ; 146(1-2): 143-52, 2000 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10913891

RESUMEN

To understand the auditory neural response to electrical stimuli similar to those used in a cochlear implant, it will be necessary to understand the neural refraction and summation response kinetics. Evidence exists indicating that the cell soma may alter the auditory neural response kinetics and could be the site of conduction failure for excitation initiated on the peripheral process. There is, however, reason to believe that the excitation site in some healthy, type I neurons and in pathological, type III neurons is the central process of the cell. To characterize the neural response to activation at a controlled central process site, cat auditory neurons were stimulated with an intrameatal electrode, and the summation and refraction response kinetics were measured. This approach was used to: (1) characterize the behavior of the neural response to central process excitation; (2) make comparisons between intrameatal excitation at a known central site and scala tympani excitation at an unknown site; and (3) provide membrane characterization free from the possible alteration of membrane kinetics produced by the cell soma. The membrane kinetics measured using intrameatal stimulation differ from those recorded with scala tympani stimulation indicating that the mechanisms for scala tympani and intrameatal stimulation differ.


Asunto(s)
Cóclea/inervación , Nervio Coclear/fisiología , Modelos Neurológicos , Animales , Umbral Auditivo , Gatos , Membrana Celular/fisiología , Implantes Cocleares , Estimulación Eléctrica , Estudios de Evaluación como Asunto , Potenciales Evocados Auditivos del Tronco Encefálico , Neuronas/fisiología
16.
J Biol Chem ; 275(39): 29980-5, 2000 Sep 29.
Artículo en Inglés | MEDLINE | ID: mdl-10913135

RESUMEN

Microtubule-damaging agents arrest cells at G(2)/M and induce apoptosis in association with phosphorylation of the anti-apoptotic proteins Bcl-2 and Bcl-X(L). Because microtubule inhibitors activate JNK, we sought to determine whether JNK was responsible for Bcl-2/Bcl-X(L) phosphorylation in KB-3 cells treated with vinblastine. Two major endogenous forms of JNK, p46(JNK1) and p54(JNK2), were present in KB-3 cells, and both isoforms were activated by vinblastine as determined by Mono Q chromatography. We used antisense oligonucleotides (AS) to specifically inhibit their expression. A combination of AS-JNK1 with AS-JNK2 inhibited by 80% vinblastine-induced phosphorylation of two known JNK substrates, c-Jun and ATF-2. In addition, AS-JNK1/2 inhibited vinblastine-induced phosphorylation of Bcl-2 by 85% and that of Bcl-X(L) by 65%. Stable expression of the JNK scaffold protein JIP-1 blocked vinblastine-induced phosphorylation of c-Jun and ATF-2, but did not affect Bcl-2/Bcl-X(L) phosphorylation, confirming a bifurcation in JNK signaling involving both nuclear and non-nuclear substrates. Vinblastine-induced phosphorylation of Raf-1 was unaffected by AS-JNK1/2 and was associated with loss of activity for MEK substrate in vitro and inactivation of ERK in vivo. These results provide evidence for a direct role of the JNK pathway in apoptotic regulation through Bcl-2/Bcl-X(L) phosphorylation.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales , Quinasas de Proteína Quinasa Activadas por Mitógenos/metabolismo , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Proteínas Proto-Oncogénicas c-raf/metabolismo , Vinblastina/farmacología , Proteínas Portadoras/metabolismo , Activación Enzimática , Humanos , Isoenzimas/metabolismo , Sistema de Señalización de MAP Quinasas , Proteína Quinasa 8 Activada por Mitógenos , Proteína Quinasa 9 Activada por Mitógenos , Proteínas Quinasas Activadas por Mitógenos/genética , Oligonucleótidos Antisentido/farmacología , Fosforilación , Células Tumorales Cultivadas , Proteína bcl-X
17.
Eur J Pediatr Surg ; 10 Suppl 1: 13-7, 2000 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11214824

RESUMEN

INTRODUCTION: Tethering is assumed to be the primary cause of deterioration seen in children with transitional lipomyelomeningocele as they age. The inevitability of deterioration has led to recommendations for prophylactic interventions to stabilize or prevent further clinical deterioration. OBJECTIVE: Determine the frequency and patterns of functional deterioration observed after successful untethering in patients with transitional lipomyelomeningocele and compare functional outcomes with what is known regarding untreated patients. METHODS: Fifty patients having transitional LMMC, treated at a single institution and followed in a multidisciplinary clinic were retrospectively reviewed to determine their clinical status prior to untethering, and the time to development of new symptoms or signs following untethering. RESULTS: 82% of patients were diagnosed and 78% underwent untethering prior to one year of age. All patients had a cutaneous lumbosacral lipoma, 22 patients were considered normal at presentation and 28 showed abnormalities on clinical examination. Forty-nine patients were untethered successfully and all were available for follow-up ranging from 2 to 138 months (mean 39 months). Acute morbidity was limited to transient neurogenic bladder dysfunction and minor wound complications. Late clinical deterioration occurred in the majority of patients. Orthopedic and neurological deterioration occurred over the first 60 months following untethering and urological deterioration occurred thereafter. CONCLUSIONS: Functional loss after untethering is common and the pattern of loss is likely a reflection of the ability to detect abnormalities in this infant population. Untethering does not usually result in permanent acute morbidity, and does not prevent longer-term functional deterioration. The ratio of asymptomatic to symptomatic patients at follow-up in this operative series is similar to age-matched historical series of untreated patients.


Asunto(s)
Lipoma/cirugía , Meningomielocele/cirugía , Complicaciones Posoperatorias/epidemiología , Espina Bífida Oculta/complicaciones , Neoplasias de la Médula Espinal/cirugía , Colombia Británica/epidemiología , Niño , Preescolar , Femenino , Humanos , Lactante , Lipoma/complicaciones , Región Lumbosacra , Masculino , Meningomielocele/complicaciones , Enfermedades Musculoesqueléticas/epidemiología , Enfermedades Musculoesqueléticas/etiología , Enfermedades del Sistema Nervioso/epidemiología , Enfermedades del Sistema Nervioso/etiología , Estudios Retrospectivos , Neoplasias de la Médula Espinal/complicaciones , Análisis de Supervivencia , Factores de Tiempo , Resultado del Tratamiento , Enfermedades Urológicas/epidemiología , Enfermedades Urológicas/etiología
18.
Hear Res ; 127(1-2): 108-18, 1999 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-9925022

RESUMEN

We describe a novel signal processing strategy for cochlear implants designed to emphasize stochastic independence across the excited neural population. The strategy is based on the observation that high rate pulse trains may produce random spike patterns in auditory nerve fibers that are statistically similar to those produced by spontaneous activity in the normal cochlea. We call this activity 'pseudospontaneous'. A supercomputer-based computational model of a population of auditory nerve fibers suggests that different average rates of pseudospontaneous activity can be created by varying the stimulus current of a fixed-amplitude, high-rate pulse train, e.g. 5000 pps. Electrically-evoked compound action potentials recorded in a human cochlear implant subject are consistent with the hypothesis that such a stimulus can desynchronize the fiber population. This desynchronization may enhance neural representation of temporal detail and dynamic range with a cochlear implant and eliminate a major difference between acoustic and electric hearing.


Asunto(s)
Nervio Vestibulococlear/fisiología , Implantes Cocleares , Estimulación Eléctrica , Potenciales Evocados/fisiología , Potenciales Evocados Auditivos/fisiología , Humanos , Modelos Neurológicos , Fibras Nerviosas/fisiología , Procesos Estocásticos
19.
Am J Otol ; 19(6): 758-61, 1998 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-9831150

RESUMEN

OBJECTIVE: This study aimed to assess, in one profoundly hearing impaired subject, potential benefits and limitations in placing bilaterally implanted scala tympani electrode arrays under control of a single speech processor. STUDY DESIGN: All available stimulation sites in both ears were compared in studies of pitch discrimination and pitch ranking, identifying three bilateral pairs capable of supporting interaural comparisons with no perceptible difference in pitch. Using those pairs, the subject's ability to lateralize sound was studied as a function of interaural time delay and interaural amplitude difference. Consonant identification scores were obtained for continuous interleaved sampling processors using various unilateral and bilateral combinations of electrodes. RESULTS: For loudness-matched stimuli composed of 50-msec bursts of 80-microsec/phase pulses at 480 pulses/sec, the subject was able to identify the ear receiving the earlier onset for interaural delays at least as brief as 150 microsec for all three matched pairs. For similar simultaneous stimuli, the subject could identify the ear receiving the louder signal for the smallest deviations from loudness-matched amplitudes available from the implanted electronics. The consonant studies found no evidence that bilateral stimulation per se degrades speech processor performance, even for arbitrary divisions of information between the two ears. Additional contralateral as well as ipsilateral channels were observed to improve speech processor performance. CONCLUSIONS: The ability of this subject to lateralize sounds on the basis of interaural delay or loudness difference, combined with the consonant identification results, supports further use of coordinated binaural stimulation to improve cochlear implant users' ability to understand speech, especially in the presence of competing speech noise.


Asunto(s)
Implantes Cocleares , Equipos de Comunicación para Personas con Discapacidad , Sordera/fisiopatología , Sordera/cirugía , Procesamiento de Señales Asistido por Computador , Percepción del Habla , Adulto , Sordera/microbiología , Encefalitis/complicaciones , Humanos , Listeriosis/complicaciones , Percepción Sonora , Localización de Sonidos , Resultado del Tratamiento
20.
Vision Res ; 38(22): 3655-62, 1998 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-9893796

RESUMEN

Scotopic sensitivity was compared in young and older adults in good eye health after individualized correction for age-related changes in lens density and control of pupil diameter. Unlike earlier studies on this topic, fundus photography and a grading scale were used to characterize macular health in the older sample. Twenty-four young adults (mean age 27) and 25 older adults (mean age 70 years) underwent scotopic sensitivity testing after 30 min of dark adaptation. Light sensitivity for a 450 nm target was measured at 4, 7, 32, and 38 degrees both nasally and temporally along the horizontal meridian. Lens density was estimated using Sample's method. On average, older adults exhibited a 0.5 log unit decrease in sensitivity even with lens density taken into account, which did not vary with target eccentricity or nasal/temporal hemifield. Although 60% of older subjects exhibited fundoscopic signs of early age-related maculopathy (ARM), even those free from these signs demonstrated a half log unit sensitivity loss, suggesting that this impairment may represent a biological aging process. We found no psychophysical evidence that scotopic sensitivity loss in older adults with relatively good retinal health is accentuated in the peri-macula, even though anatomical studies on donor retinas from older adults have indicated that this area has heightened rod loss.


Asunto(s)
Envejecimiento/fisiología , Adaptación a la Oscuridad , Percepción Visual/fisiología , Adulto , Anciano , Sensibilidad de Contraste , Femenino , Humanos , Cristalino , Masculino , Psicofísica , Retina/anatomía & histología , Agudeza Visual , Campos Visuales
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA