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1.
Prog Urol ; 32(11): 776-783, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35941009

RESUMEN

BACKGROUND: A weakened pelvic floor is less efficient counteracting the increased intra-abdominal pressure during exercise. While intra-abdominal pressure is higher in Sit-up than in Curl-up, Sit-up continues to be practiced in fitness classes. This raises the question of whether it has advantages over the Curl-up for instance in reducing the interrecti distance (IRD), a goal searched by many parous women. IRD has been shown to be acutely reduced during Curl-up. OBJECTIVES: To determine if the IRD is more reduced during Sit-up than during Curl-up. METHODS: Parous women with an IRD greater than 15mm were included in the study. IRD was measured at 20mm above umbilicus with a caliper in Head-lift, Curl-up, Sit-up and Drawing-in+Curl-up. IRD was compared across the four conditions using a one-way Anova test with repeated measures and Bonferroni correction between pairwise comparisons. RESULTS: Nineteen parous women aged between 28 and 54 participated in this study. Compared to Head-lift (20.3±3.9mm), the IRD was significantly decreased during the Curl-up (12.2±3.0mm) and the Sit-up (12.1±3.6mm), but not during the Drawing-in+Curl-up (18.4±4.9mm). There was no significant difference in IRD between Curl-up and Sit-up. CONCLUSION: IRD was similarly acutely reduced during Curl-up and Sit-up. The long-term effect of Curl-up on the IRD and on the pelvic floor muscles needs to be studied. IMPACT: To reduce IRD in parous women Curl-up rather than Sit-up should be practiced. Fitness coaches should consider this information especially with classes attended by parous women, many of whom complain about pelvic floor disorders. LEVEL OF EVIDENCE: EL05.


Asunto(s)
Trastornos del Suelo Pélvico , Diafragma Pélvico , Adulto , Estudios Transversales , Ejercicio Físico , Femenino , Humanos , Persona de Mediana Edad , Ultrasonografía
2.
ESMO Open ; 7(2): 100400, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35247870

RESUMEN

BACKGROUND: Microsatellite instability (MSI)/mismatch repair deficiency (dMMR) is a key genetic feature which should be tested in every patient with colorectal cancer (CRC) according to medical guidelines. Artificial intelligence (AI) methods can detect MSI/dMMR directly in routine pathology slides, but the test performance has not been systematically investigated with predefined test thresholds. METHOD: We trained and validated AI-based MSI/dMMR detectors and evaluated predefined performance metrics using nine patient cohorts of 8343 patients across different countries and ethnicities. RESULTS: Classifiers achieved clinical-grade performance, yielding an area under the receiver operating curve (AUROC) of up to 0.96 without using any manual annotations. Subsequently, we show that the AI system can be applied as a rule-out test: by using cohort-specific thresholds, on average 52.73% of tumors in each surgical cohort [total number of MSI/dMMR = 1020, microsatellite stable (MSS)/ proficient mismatch repair (pMMR) = 7323 patients] could be identified as MSS/pMMR with a fixed sensitivity at 95%. In an additional cohort of N = 1530 (MSI/dMMR = 211, MSS/pMMR = 1319) endoscopy biopsy samples, the system achieved an AUROC of 0.89, and the cohort-specific threshold ruled out 44.12% of tumors with a fixed sensitivity at 95%. As a more robust alternative to cohort-specific thresholds, we showed that with a fixed threshold of 0.25 for all the cohorts, we can rule-out 25.51% in surgical specimens and 6.10% in biopsies. INTERPRETATION: When applied in a clinical setting, this means that the AI system can rule out MSI/dMMR in a quarter (with global thresholds) or half of all CRC patients (with local fine-tuning), thereby reducing cost and turnaround time for molecular profiling.


Asunto(s)
Neoplasias Colorrectales , Inestabilidad de Microsatélites , Inteligencia Artificial , Neoplasias Colorrectales/diagnóstico , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/patología , Reparación de la Incompatibilidad de ADN/genética , Detección Precoz del Cáncer , Humanos
3.
ESMO Open ; 7(2): 100419, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35305400

RESUMEN

BACKGROUND: The programmed death-ligand 1 inhibitor atezolizumab had shown clinical activity against several advanced malignancies. PATIENTS AND METHODS: This phase II, open-label basket study (NCT02458638) was conducted in 16 main cohorts of patients aged ≥18 years with stage III or IV solid tumors. In stage I, 12 patients were enrolled into each cohort. Treatment was atezolizumab 1200 mg intravenously every 3 weeks until loss of clinical benefit or unacceptable toxicity. The primary efficacy endpoint was the non-progression rate (NPR) at 18 weeks in treated, assessable patients. NPR ≤20% was not of interest for development as monotherapy, and NPR ≥40% was defined as the threshold of benefit/success. If ≥3 patients had non-progressive disease in stage I (interim analysis), 13 additional patients could be enrolled into stage II (final analysis). Secondary efficacy and safety endpoints were also evaluated. RESULTS: Overall, 474 patients were enrolled and treated; 433 were included in the efficacy set. Due partly to slow recruitment because of competing trials and limited efficacy at interim analyses, enrollment was stopped early, including in cohorts that passed stage I boundaries of success. NPR was >20% in five cohorts: cervical cancer {n = 27; NPR 44.4% [95% confidence interval (CI) 25.5% to 64.7%]}; follicular/papillary thyroid cancer [n = 11; 54.5% (95% CI 23.4% to 83.3%)]; thymoma [n = 13; 76.9% (95% CI: 46.2% to 95.0%)]; gastroenteropancreatic (GEP) and lung neuroendocrine tumors [NETs; n = 24; 41.7% (95% CI 22.1% to 63.4%)], and low/intermediate grade carcinoid GEP and lung NETs [n = 12; 58.3% (95% CI 27.7% to 84.8%)]. Treatment-related adverse events occurred in 55.3% of patients overall, and at grade 3, 4, and 5 in 10.3%, 1.7%, and 0.4%, respectively. CONCLUSIONS: Atezolizumab monotherapy was effective in the cervical cancer cohort. The interim benefit threshold was crossed in patients with follicular/papillary thyroid cancer, thymoma, and GEP and lung NETs, but recruitment was stopped before these signals could be confirmed in stage II. Safety was consistent with previous findings.


Asunto(s)
Anticuerpos Monoclonales Humanizados , Neoplasias , Adolescente , Adulto , Anticuerpos Monoclonales Humanizados/efectos adversos , Femenino , Humanos , Neoplasias/tratamiento farmacológico , Neoplasias/patología , Timoma , Neoplasias del Timo , Cáncer Papilar Tiroideo , Neoplasias de la Tiroides , Neoplasias del Cuello Uterino
4.
Eur J Nucl Med Mol Imaging ; 48(12): 3918-3924, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34018010

RESUMEN

PURPOSE: A high expression of fibroblast activation protein (FAP) was observed in multiple sarcomas, indicating an enormous potential for PET/CT using 68Ga-radiolabeled inhibitors of FAP (FAPI). Therefore, this retrospective study aimed to evaluate the role of the novel hybrid imaging probe for sarcomas as a first clinical evaluation. METHODS: A cohort of 15 patients underwent 68Ga-FAPI-PET/CT for staging or restaging. The acquisition of PET scans was performed 60 min after administration of 127 to 308 MBq of the tracer. The uptake of 68Ga-FAPI in malignant tissue as well as in healthy organs was quantified by standardized uptake values SUVmean and SUVmax. RESULTS: Excellent tumor-to-background ratios (> 7) could be achieved due to low background activity and high SUVmax in primary tumors (median 7.16), local relapses (median 11.47), and metastases (median 6.29). The highest uptake was found for liposarcomas and high-grade disease (range 18.86-33.61). A high SUVmax (> 10) was observed for clinically more aggressive disease. CONCLUSION: These preliminary findings suggest a high potential for the clinical use of 68Ga-FAPI-PET/CT for patients diagnosed with sarcoma.


Asunto(s)
Tomografía Computarizada por Tomografía de Emisión de Positrones , Sarcoma , Humanos , Ligandos , Recurrencia Local de Neoplasia , Estudios Retrospectivos , Sarcoma/diagnóstico por imagen
5.
Eur J Cancer ; 90: 122-129, 2018 02.
Artículo en Inglés | MEDLINE | ID: mdl-29306769

RESUMEN

BACKGROUND: Immune checkpoint therapy has dramatically changed treatment options in patients with metastatic melanoma. However, a relevant part of patients still does not respond to treatment. Data regarding the prognostic or predictive significance of preexisting immune responses against tumour antigens are conflicting. Retrospective data suggested a higher clinical benefit of ipilimumab in melanoma patients with preexisting NY-ESO-1-specific immunity. PATIENTS AND METHODS: Twenty-five patients with previously untreated or treated metastatic melanoma and preexisting humoural immune response against NY-ESO-1 received ipilimumab at a dose of 10 mg/kg in week 1, 4, 7, 10 followed by 3-month maintenance treatment for a maximum of 48 weeks. Primary endpoint was the disease control rate (irCR, irPR or irSD) according to immune-related response criteria (irRC). Secondary endpoints included the disease control rate according to RECIST criteria, progression-free survival and overall survival (OS). Humoural and cellular immune responses against NY-ESO-1 were analysed from blood samples. RESULTS: Disease control rate according to irRC was 52%, irPR was observed in 36% of patients. Progression-free survival according to irRC was 7.8 months, according to RECIST criteria it was 2.9 months. Median OS was 22.7 months; the corresponding 1-year survival rate was 66.8%. Treatment-related grade 3 AEs occurred in 36% with no grade 4-5 AEs. No clear association was found between the presence of NY-ESO-1-specific cellular or humoural immune responses and clinical activity. CONCLUSION: Ipilimumab demonstrated clinically relevant activity within this biomarker-defined population. NY-ESO-1 positivity, as a surrogate for a preexisting immune response against tumour antigens, might help identifying patients with a superior outcome from immune checkpoint blockade. CLINICAL TRIAL INFORMATION: NCT01216696.


Asunto(s)
Antígenos de Neoplasias/inmunología , Antineoplásicos Inmunológicos/uso terapéutico , Ipilimumab/uso terapéutico , Melanoma/tratamiento farmacológico , Melanoma/inmunología , Proteínas de la Membrana/inmunología , Neoplasias Cutáneas/tratamiento farmacológico , Neoplasias Cutáneas/inmunología , Adulto , Anciano , Anciano de 80 o más Años , Supervivencia sin Enfermedad , Femenino , Humanos , Inmunidad Humoral , Masculino , Melanoma/mortalidad , Persona de Mediana Edad , Neoplasias Cutáneas/mortalidad , Melanoma Cutáneo Maligno
6.
Leukemia ; 31(7): 1570-1581, 2017 07.
Artículo en Inglés | MEDLINE | ID: mdl-27890927

RESUMEN

Despite therapeutic advances, multiple myeloma (MM) remains an incurable disease, predominantly because of the development of drug resistance. The activator protein-1 (AP-1) transcription factor family has been implicated in a multitude of physiologic processes and tumorigenesis; however, its role in MM is largely unknown. Here we demonstrate specific and rapid induction of the AP-1 family member JunB in MM cells when co-cultured with bone marrow stromal cells. Supporting a functional key role of JunB in MM pathogenesis, knockdown of JUNB significantly inhibited in vitro MM cell proliferation and survival. Consistently, induced silencing of JUNB markedly decreased tumor growth in a murine MM model of the microenvironment. Subsequent gene expression profiling revealed a role for genes associated with apoptosis, DNA replication and metabolism in driving the JunB-mediated phenotype in MM cells. Importantly, knockdown of JUNB restored the response to dexamethasone in dexamethasone-resistant MM cells. Moreover, 4-hydroxytamoxifen-induced activation of a JunB-ER fusion protein protected dexamethasone-sensitive MM cells against dexamethasone- and bortezomib-induced cytotoxicity. In summary, our results demonstrate for the first time a specific role for AP-1/JunB in MM cell proliferation, survival and drug resistance, thereby strongly supporting that this transcription factor is a promising new therapeutic target in MM.


Asunto(s)
Médula Ósea/patología , Mieloma Múltiple/patología , Factores de Transcripción/fisiología , Microambiente Tumoral , Animales , Bortezomib/farmacología , Proliferación Celular , Dexametasona/farmacología , Resistencia a Antineoplásicos , Femenino , Humanos , Ratones , Mieloma Múltiple/tratamiento farmacológico , Mieloma Múltiple/mortalidad , FN-kappa B/fisiología
8.
Neurobiol Dis ; 75: 177-85, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25576395

RESUMEN

Electrophysiological changes in basal ganglia neurons are hypothesized to underlie motor dysfunction in Parkinson's disease (PD). Previous results in head-restrained MPTP-treated non-human primates have suggested that increased bursting within the basal ganglia and related thalamic and cortical areas may be a hallmark of pathophysiological activity. In this study, we investigated whether there is increased bursting in substantia nigra pars reticulata (SNpr) output neurons in anesthetized and awake, head-restrained unilaterally lesioned 6-OHDA mice when compared to control mice. Confirming previous studies, we show that there are significant changes in the firing rate and pattern in SNpr neuron activity under urethane anesthesia. The regular firing pattern of control urethane-anesthetized SNpr neurons was not present in the 6-OHDA-lesioned group, as the latter neurons instead became phase locked with cortical slow wave activity (SWA). Next, we examined whether such robust electrophysiological changes between groups carried over to the awake state. SNpr neurons from both groups fired at much higher frequencies in the awake state than in the anesthetized state and surprisingly showed only modest changes between awake control and 6-OHDA groups. While there were no differences in firing rate between groups in the awake state, an increase in the coefficient of variation (CV) was observed in the 6-OHDA group. Contrary to the bursting hypothesis, this increased CV was not due to changes in bursting but was instead due to a mild increase in pausing. Together, these results suggest that differences in SNpr activity between control and 6-OHDA lesioned mice may be strongly influenced by changes in network activity during different arousal and behavioral states.


Asunto(s)
Potenciales de Acción/fisiología , Anestésicos/farmacología , Neuronas/fisiología , Trastornos Parkinsonianos/fisiopatología , Porción Reticular de la Sustancia Negra/fisiopatología , Vigilia/fisiología , Potenciales de Acción/efectos de los fármacos , Animales , Ritmo beta/efectos de los fármacos , Dopamina/metabolismo , Ratones Endogámicos C57BL , Ratones Transgénicos , Microelectrodos , Actividad Motora/fisiología , Corteza Motora/efectos de los fármacos , Corteza Motora/fisiopatología , Neuronas/efectos de los fármacos , Oxidopamina , Trastornos Parkinsonianos/patología , Porción Reticular de la Sustancia Negra/efectos de los fármacos , Porción Reticular de la Sustancia Negra/patología , Restricción Física , Uretano/farmacología , Vigilia/efectos de los fármacos
9.
Br Poult Sci ; 55(5): 585-91, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25188272

RESUMEN

Water used in a modern poultry processing line was tested from October 2005 to June 2006 to determine the level of bacteria in an abattoir in Germany. A total of 420 water samples were taken from 14 processing sites (PSs), at 10 times, and from three different hours of the working shift at three sampling hours (SHs) at 5:00 a.m. (SH 1), 9:00 a.m. (SH 2) and 12:00 a.m. (SH 3). Each sample was assessed for the aerobic plate count (APC) and the prevalence of Salmonella, Campylobacter, Listeria and Yersinia over 30 sampling weeks. The APC numbers of each PS from three SHs were compared, and the prevalence of Salmonella, Campylobacter, Listeria and Yersinia from each PS of three SHs was determined as well as change from the initial PS to the end of the processing line. A total of 46 water samples were positive for Salmonella, 120 positive for Campylobacter and 4 positive for Listeria. None of the water samples was found to be positive for Yersinia. During the course of the day, the APC increased. Salmonella was mostly found during SH 1 (5 a.m.) in water from all PSs. A high number of Campylobacter were observed at SH 2 (9 a.m.) and SH 3 (12 a.m.) from all PSs. The results show that water, which is still used in substantial amounts in present poultry processing technology, can serve as a carrier for Salmonella and Campylobacter. The findings indicate that birds might progressively contaminate the equipment and become contaminated via the same equipment, that water at every processing position of the line constitutes a risk and that more attention should be paid to effective water management in the processing plan.


Asunto(s)
Mataderos , Infecciones por Campylobacter/veterinaria , Pollos , Infecciones por Enterobacteriaceae/veterinaria , Microbiología de Alimentos , Listeriosis/veterinaria , Enfermedades de las Aves de Corral/epidemiología , Microbiología del Agua , Animales , Campylobacter/aislamiento & purificación , Infecciones por Campylobacter/epidemiología , Infecciones por Campylobacter/microbiología , Recuento de Colonia Microbiana/veterinaria , Enterobacteriaceae/aislamiento & purificación , Infecciones por Enterobacteriaceae/epidemiología , Infecciones por Enterobacteriaceae/microbiología , Manipulación de Alimentos , Alemania/epidemiología , Listeria/aislamiento & purificación , Listeriosis/epidemiología , Listeriosis/microbiología , Enfermedades de las Aves de Corral/microbiología , Prevalencia , Factores de Riesgo
10.
Ann Oncol ; 25(5): 1018-25, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24585720

RESUMEN

BACKGROUND: Initially, unresectable colorectal liver metastases can be resected after response to chemotherapy. While cetuximab has been shown to increase response and resection rates, the survival outcome for this conversion strategy needs further evaluation. PATIENTS AND METHODS: Patients with technically unresectable and/or ≥5 liver metastases were treated with FOLFOX/cetuximab (arm A) or FOLFIRI/cetuximab (arm B) and evaluated with regard to resectability every 2 months. Tumour response and secondary resection data have been reported previously. A final analysis of overall survival (OS) and progression-free survival (PFS) was carried out in December 2012. RESULTS: Between December 2004 and March 2008, 56 patients were randomised to arm A, 55 to arm B. The median OS was 35.7 [95% confidence interval (CI) 27.2-44.2] months [arm A: 35.8 (95% CI 28.1-43.6), arm B: 29.0 (95% CI 16.0-41.9) months, HR 1.03 (95% CI 0.66-1.61), P = 0.9]. The median PFS was 10.8 (95% CI 9.3-12.2) months [arm A: 11.2 (95% CI 7.2-15.3), arm B: 10.5 (95% CI 8.9-12.2) months, HR 1.18 (95% CI 0.79-1.74), P = 0.4]. Patients who underwent R0 resection (n = 36) achieved a better median OS [53.9 (95% CI 35.9-71.9) months] than those who did not [21.9 (95% CI 17.1-26.7) months, P < 0.001]. The median disease-free survival for R0 resected patients was 9.9 (95% CI 5.8-14.0) months, and the 5-year OS rate was 46.2% (95% CI 29.5% to 62.9%). CONCLUSIONS: This study confirms a favourable long-term survival for patients with initially sub-optimal or unresectable colorectal liver metastases who respond to conversion therapy and undergo secondary resection. Both FOLFOX/FOLFIRI plus cetuximab, appear to be appropriate regimens for 'conversion' treatment in patients with K-RAS codon 12/13/61 wild-type tumours. Thus, liver surgery can be considered curative or alternatively as an additional 'line of therapy' in those patients who are not cured. CLINICAL TRIAL NUMBER: NCT00153998, www.clinicaltrials.gov.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Camptotecina/análogos & derivados , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Hepáticas/tratamiento farmacológico , Anciano , Anticuerpos Monoclonales Humanizados/administración & dosificación , Camptotecina/uso terapéutico , Cetuximab , Neoplasias Colorrectales/mortalidad , Neoplasias Colorrectales/patología , Supervivencia sin Enfermedad , Femenino , Fluorouracilo/uso terapéutico , Humanos , Estimación de Kaplan-Meier , Leucovorina/uso terapéutico , Neoplasias Hepáticas/mortalidad , Neoplasias Hepáticas/secundario , Masculino , Persona de Mediana Edad , Análisis Multivariante , Compuestos Organoplatinos/uso terapéutico , Modelos de Riesgos Proporcionales , Resultado del Tratamiento
11.
Bone Marrow Transplant ; 49(3): 443-8, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24317122

RESUMEN

Patients undergoing allo-HCT often experience a substantial loss in physical performance. We have recently published the general effectiveness of an exercise intervention in 105 allo-HCT patients on physical performance and psychosocial well-being. However, predictor variables for differentiated treatment response remained unclear. To determine the impact of basic physical performance on treatment response, we assessed muscle strength and endurance performance at four assessment points before and after allo-HCT. The exercise group started training 2 weeks before admission and ended 6-8 weeks after discharge. Comparing initially fit with unfit classified patients, the fit patients lost 31% of the strength of the knee-extensors, whereas the unfit patients lost only 1% (P<0.05). For endurance capacity, fit patients lost 4% of their walking capability, whereas unfit patients gained 13% (P<0.05). The individual percent change was statistically different at the 0.05 level in all measures of physical performance. Individual training response in allo-HCT patients strongly depends on the initial physical performance level. Unfit patients can be trained safely and may benefit more from this exercise intervention than fit patients. This result is of major clinical relevance and should encourage hematologists to promote exercise even more in impaired/unfit allo-HCT patients.


Asunto(s)
Terapia por Ejercicio/métodos , Terapia por Ejercicio/psicología , Neoplasias Hematológicas/psicología , Neoplasias Hematológicas/terapia , Trasplante de Células Madre Hematopoyéticas , Calidad de Vida , Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Fuerza Muscular , Estudios Prospectivos , Trasplante Homólogo , Resultado del Tratamiento , Caminata , Adulto Joven
12.
J Neurophysiol ; 110(12): 2792-805, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24068758

RESUMEN

Numerous studies have suggested that alpha-synuclein plays a prominent role in both familial and idiopathic Parkinson's disease (PD). Mice in which human alpha-synuclein is overexpressed (ASO) display progressive motor deficits and many nonmotor features of PD. However, it is unclear what in vivo pathophysiological mechanisms drive these motor deficits. It is also unknown whether previously proposed pathophysiological features (i.e., increased beta oscillations, bursting, and synchronization) described in toxin-based, nigrostriatal dopamine-depletion models are also present in ASO mice. To address these issues, we first confirmed that 5- to 6-mo-old ASO mice have robust motor dysfunction, despite the absence of significant nigrostriatal dopamine degeneration. In the same animals, we then recorded simultaneous single units and local field potentials (LFPs) in the substantia nigra pars reticulata (SNpr), the main basal ganglia output nucleus, and one of its main thalamic targets, the ventromedial nucleus, as well as LFPs in the primary motor cortex in anesthetized ASO mice and their age-matched, wild-type littermates. Neural activity was examined during slow wave activity and desynchronized cortical states, as previously described in 6-hydroxydopamine-lesioned rats. In contrast to toxin-based models, we found a small decrease, rather than an increase, in beta oscillations in the desynchronized state. Similarly, synchronized burst firing of nigral neurons observed in toxin-based models was not observed in ASO mice. Instead, we found more subtle changes in pauses of SNpr firing compared with wild-type control mice. Our results suggest that the pathophysiology underlying motor dysfunction in ASO mice is distinctly different from striatal dopamine-depletion models of parkinsonism.


Asunto(s)
Ritmo beta , Neuronas/fisiología , Enfermedad de Parkinson Secundaria/fisiopatología , Enfermedad de Parkinson/fisiopatología , Sustancia Negra/fisiopatología , Tálamo/fisiopatología , alfa-Sinucleína/genética , Potenciales de Acción , Animales , Humanos , Masculino , Ratones , Corteza Motora/fisiopatología , Neuronas/metabolismo , Oxidopamina/toxicidad , Enfermedad de Parkinson/genética , Enfermedad de Parkinson Secundaria/inducido químicamente , Sustancia Negra/citología , Sustancia Negra/metabolismo , Tálamo/citología , Tálamo/metabolismo , alfa-Sinucleína/metabolismo
13.
Nano Lett ; 12(9): 4953-9, 2012 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-22935029

RESUMEN

Stacking of two-dimensional electron gases (2DEGs) obtained by δ-doping of Ge and patterned by scanning probe lithography is a promising approach to realize ultrascaled 3D epitaxial circuits, where multiple layers of active electronic components are integrated both vertically and horizontally. We use atom probe tomography and magnetotransport to correlate the real space 3D atomic distribution of dopants in the crystal with the quantum correction to the conductivity observed at low temperatures, probing if closely stacked δ-layers in Ge behave as independent 2DEGs. We find that at a separation of 9 nm the stacked-2DEGs, while interacting, still maintain their individuality in terms of electron transport and show long phase coherence lengths (∼220 nm). Strong vertical electron confinement is crucial to this finding, resulting in an interlayer scattering time much longer (∼1000 × ) than the scattering time within the dopant plane.


Asunto(s)
Gases/química , Germanio/química , Nanoestructuras/química , Nanoestructuras/ultraestructura , Conductividad Eléctrica , Transporte de Electrón , Campos Magnéticos , Ensayo de Materiales , Tamaño de la Partícula , Estadística como Asunto , Temperatura
15.
Nat Commun ; 3: 935, 2012 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-22760634

RESUMEN

Fabrication of ultrasharp probes is of interest for many applications, including scanning probe microscopy and electron-stimulated patterning of surfaces. These techniques require reproducible ultrasharp metallic tips, yet the efficient and reproducible fabrication of these consumable items has remained an elusive goal. Here we describe a novel biased-probe field-directed sputter sharpening technique applicable to conductive materials, which produces nanometer and sub-nanometer sharp W, Pt-Ir and W-HfB(2) tips able to perform atomic-scale lithography on Si. Compared with traditional probes fabricated by etching or conventional sputter erosion, field-directed sputter sharpened probes have smaller radii and produce lithographic patterns 18-26% sharper with atomic-scale lithographic fidelity.

16.
Neuroscience ; 219: 92-110, 2012 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-22659567

RESUMEN

A neuron's phase response curve (PRC) shows how inputs arriving at different times during the spike cycle differentially affect the timing of subsequent spikes. Using a full morphological model of a globus pallidus (GP) neuron, we previously demonstrated that dendritic conductances shape the PRC in a spike frequency-dependent manner, suggesting different functional roles of perisomatic and distal dendritic synapses in the control of patterned network activity. In the present study we extend this analysis to examine the impact of physiologically realistic high conductance states on somatic and dendritic PRCs and the time course of spike train perturbations. First, we found that average somatic and dendritic PRCs preserved their shapes and spike frequency dependence when the model was driven by spatially-distributed, stochastic conductance inputs rather than tonic somatic current. However, responses to inputs during specific synaptic backgrounds often deviated substantially from the average PRC. Therefore, we analyzed the interactions of PRC stimuli with transient fluctuations in the synaptic background on a trial-by-trial basis. We found that the variability in responses to PRC stimuli and the incidence of stimulus-evoked added or skipped spikes were stimulus-phase-dependent and reflected the profile of the average PRC, suggesting commonality in the underlying mechanisms. Clear differences in the relation between the phase of input and variability of spike response between dendritic and somatic inputs indicate that these regions generally represent distinct dynamical subsystems of synaptic integration with respect to influencing the stability of spike time attractors generated by the overall synaptic conductance.


Asunto(s)
Globo Pálido/fisiología , Modelos Neurológicos , Neuronas/fisiología , Sinapsis/fisiología , Potenciales de Acción/fisiología , Humanos
17.
Gait Posture ; 35(1): 29-35, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21872474

RESUMEN

In this study we investigated the effect of a mechanical perturbation of unexpected timing during human running. With the use of a powered exoskeleton, we evoked a dorsiflexion of the right ankle during its swing phase while subjects ran on a treadmill. The perturbation resulted in an increase of the right ankle dorsiflexion of at least 5°. The first two as well as the next five steps after the perturbation were analyzed to observe the possible immediate and late biomechanical adjustments. In all cases subjects continued to run after the perturbation. The immediate adjustments were the greatest and the most frequent when the delay between the right ankle perturbation and the subsequent right foot touch-down was the shortest. For example, the vertical impact peak force was strongly modified on the first step after the perturbations and this adjustment was correlated to a right ankle angle still clearly modified at touch-down. Some late adjustments were observed in the subsequent steps predominantly occurring during left steps. Subjects maintained the step length and the step period as constant as possible by adjusting other step parameters in order to avoid stumbling and continue running at the speed imposed by the treadmill. To our knowledge, our experiments are the first to investigate perturbations of unexpected timing during human running. The results show that humans have a time-dependent, adapted strategy to maintain their running pattern.


Asunto(s)
Articulación del Tobillo/fisiología , Carrera/fisiología , Adulto , Fenómenos Biomecánicos , Pie/fisiología , Humanos , Masculino
18.
Neuroscience ; 198: 44-53, 2011 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-21835227

RESUMEN

The globus pallidus consists of the external (GPe) and the internal (GPi) segments. The GPe and GPi have different functional roles. The GPe is located centrally within multiple basal ganglia feedforward and feedback connections. The GPi is an output nucleus of the basal ganglia. A complex interplay between intrinsic pacemaking conductances and the balance of glutamatergic and GABAergic input largely determines the rate and pattern of firing of pallidal neurons. The initial part of this article introduces recent findings made in vivo that are related to the roles of glutamatergic and GABAergic inputs in the control of pallidal activity. The latter part describes the roles of intrinsic mechanisms of GPe neurons in the integration of the synaptic inputs. The presence of dendritic voltage-gated sodium channels may allow the initiation of dendritic spikes, giving distal inputs on the long and thin GPe dendrites an opportunity to strongly shape spiking activity. Basal ganglia disorders including Parkinson's disease, hemiballismus, and dystonias are accompanied by increased irregularity and synchronized bursts of pallidal activity. These changes may be in part due to changes in the GABA release in the GPe and GPi, but also involve intrinsic cellular changes in pallidal neurons.


Asunto(s)
Globo Pálido/citología , Red Nerviosa/fisiología , Neuronas/fisiología , Potenciales de Acción/fisiología , Animales , Globo Pálido/fisiología , Red Nerviosa/citología , Vías Nerviosas/fisiología , Neuronas/citología , Neurotransmisores/metabolismo , Sinapsis/fisiología
19.
Int J Comput Dent ; 13(3): 233-50, 2010.
Artículo en Inglés, Alemán | MEDLINE | ID: mdl-20879462

RESUMEN

Treatment data from practices and specialization centers, especially in the increasingly specialized areas which university clinics do not cover, are very important for evaluating the effectiveness and efficiency of dental examination and treatment methods. In the case of paper-based documentation, the evaluation of these data usually fails because of the cost it entails. With the use of electronic medical records, this expense can be markedly lower, provided the data acquisition and storage is structured accordingly. Since access to sensitive person-related data is simplified considerably by this method, such health data are protected, especially on the European level. Other than generally assumed, this protection is not restricted solely to the confidentiality principle, but also comprises the power of disposition over the data (data protection). The result is that from a legal point of view, the treatment data cannot be readily used for scientific studies, not even by dentists and physicians who have collected the data legally during the course of their therapeutic work. The technical separation of treatment data from the personal data offers a legally acceptable solution to this problem. It must ensure that a later assignment to individual persons will not be feasible at a realistic expense ("effective anonymization"). This article describes the legal and information technology principles and their practical implementation, as illustrated by the concept of a respective compliant IT architecture for the dentaConcept CMD fact diagnostic software. Here, a special export function automatically separates the anonymized treatment data and thus facilitates multicentric studies within an institution and among dental practices.


Asunto(s)
Recolección de Datos , Informática Odontológica/legislación & jurisprudencia , Seguridad Computacional , Confidencialidad/legislación & jurisprudencia , Bases de Datos Factuales/legislación & jurisprudencia , Documentación , Registros Electrónicos de Salud/legislación & jurisprudencia , Unión Europea , Alemania , Humanos , Almacenamiento y Recuperación de la Información/métodos , Diseño de Software
20.
Cancer Immunol Immunother ; 59(9): 1389-400, 2010 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-20514540

RESUMEN

Despite spontaneous or vaccination-induced immune responses, pancreatic cancer remains one of the most deadly immunotherapy-resistant malignancies. We sought to comprehend the spectrum of pancreatic tumor-associated antigens (pTAAs) and to assess the clinical relevance of their immunogenicity. An autologous SEREX-based screening of a cDNA library constructed from a pancreatic T3N0M0/GIII specimen belonging to a long-term survivor (36 months) revealed 18 immunogenic pTAA. RT-PCR analysis displayed broad distribution of the identified antigens among normal human tissues. PNLIPRP2 and MIA demonstrated the most distinct pancreatic cancer-specific patterns. ELISA-based screening of sera for corresponding autoantibodies revealed that although significantly increased, the immunogenicity of these molecules was not a common feature in pancreatic cancer. QRT-PCR and immunohistochemistry characterized PNLIPRP2 as a robust acinar cell-specific marker whose decreased expression mirrored the disappearance of parenchyma in the diseased organ, but was not related to the presence of PNLIPRP2 autoantibodies. Analyses of MIA-known to be preferentially expressed in malignant cells-surprisingly revealed an inverse correlation between intratumoral gene expression and the emergence of autoantibodies. MIA(high) patients were autoantibody-negative and had shorter median survival when compared with autoantibody-positive MIA(low) patients (12 vs. 34 months). The observed pTAA spectrum comprised molecules associated with acinar, stromal and malignant structures, thus presenting novel targets for tumor cell-specific therapies as well as for approaches based on the bystander effects. Applying the concept of cancer immunoediting to interpret relationships between gene expression, antitumor immune responses, and clinical outcome might better discriminate between past and ongoing immune responses, consequently enabling prognostic stratification of patients and individual adjustment of immunotherapy.


Asunto(s)
Adenocarcinoma/diagnóstico , Adenocarcinoma/inmunología , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/inmunología , Adenocarcinoma/sangre , Adenocarcinoma/genética , Adenocarcinoma/mortalidad , Anciano , Antígenos de Carbohidratos Asociados a Tumores/genética , Antígenos de Carbohidratos Asociados a Tumores/inmunología , Antígenos de Carbohidratos Asociados a Tumores/metabolismo , Autoanticuerpos/sangre , Clonación Molecular , Ensayo de Inmunoadsorción Enzimática , Femenino , Biblioteca de Genes , Humanos , Inmunoquímica , Lipasa/genética , Lipasa/inmunología , Lipasa/metabolismo , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Páncreas/metabolismo , Páncreas/patología , Neoplasias Pancreáticas/sangre , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/mortalidad , Pronóstico
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