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1.
Bioelectromagnetics ; 45(2): 70-81, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37870271

RESUMEN

Low-frequency (LF) security systems, such as antitheft electronic article surveillance (EAS) gates emit strong magnetic fields that could potentially interfere with neurostimulator operation. Some patients reported pain and shocking sensations near EAS gates, even after they turned off their pulse generator. To investigate the direct voltage induction of EAS systems on neurostimulator leads, we evaluated voltages induced by two EAS systems (14 kHz continuous wave or 58 kHz pulsed) on a 40 cm sacral neurostimulator lead formed in a circular loop attached to a pulse generator that was turned off. The lead and neurostimulator were mounted in a saline-filled rectangular phantom placed within electromagnetic fields emitted by EAS systems. The measured voltage waveforms were applied to computational models of spinal nerve axons to predict whether these voltages may evoke action potentials. Additional in vitro testing was performed on the semicircular lead geometry, to study the effect of lead geometry on EAS induced voltages. While standard neurostimulator testing per ISO 14708-3:2017 recommends electromagnetic compatibility testing with LF magnetic fields for induction of malfunctions of the active electronic circuitry while generating intended stimulating pulses, our results show that close to the EAS antenna frames, the induced voltage on the lead could be strong enough to evoke action potentials, even with the pulse generator turned off. This work suggests that patient reports of pain and shocking sensations when near EAS systems could also be correlated with the direct EAS-induced voltage on neurostimulator lead.


Asunto(s)
Campos Electromagnéticos , Marcapaso Artificial , Humanos , Campos Electromagnéticos/efectos adversos , Campos Magnéticos , Electrónica , Dolor
2.
Horm Metab Res ; 51(2): 120-126, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30602178

RESUMEN

We recently reported the use of optical imaging technology to quantify facial plethora in endogenous Cushing syndrome (CS). In the present study, we studied a larger cohort of patients with Cushing disease (CD) and examined water content fraction as well as blood volume fraction as bio-optic markers for determining the efficacy of this methodology as a predictor of lasting remission after surgery for CS. We imaged 49 patients before and after transsphenoidal surgery (TSS) for Cushing disease (CD); 22 patients were also seen at 3-6 months, and 13 patients 12 months post-operatively. On all patients, we used multi-spectral imaging (MSI) to evaluate hemodynamic distributions as well as water content at a specific area of the face. We found a decrease in blood volume fraction after vs. before surgical treatment in the tested facial area in 37 of the 40 patients, as determined with biochemical markers (p<0.001). All patients that were followed up for up to 12 months showed the same decrease from preoperative values and they remained in remission from CD. We conclude that MSI can be used for the evaluation of remission from CD, at least in the immediate post-operative period and up to one year after surgery. The use of this technology can supplement biochemical and other testing for the evaluation of the various treatment modalities available for patients with CD.


Asunto(s)
Volumen Sanguíneo/fisiología , Imagen Óptica/métodos , Hipersecreción de la Hormona Adrenocorticotrópica Pituitaria (HACT)/diagnóstico por imagen , Adolescente , Adulto , Niño , Femenino , Hemodinámica/fisiología , Humanos , Masculino , Hipersecreción de la Hormona Adrenocorticotrópica Pituitaria (HACT)/sangre , Hipersecreción de la Hormona Adrenocorticotrópica Pituitaria (HACT)/cirugía , Inducción de Remisión , Resultado del Tratamiento , Adulto Joven
3.
Mol Imaging ; 132014.
Artículo en Inglés | MEDLINE | ID: mdl-25022347

RESUMEN

Basal cell carcinoma (BCC), the most common cancer in humans, appears macroscopically and microscopically similar to many other skin lesions, which makes differential diagnosis difficult. We are developing an approach for quantitative molecular imaging of BerEP4, a transmembrane biomarker for BCC, with the goal of increasing the precision and accuracy of diagnosis. This pilot study was conducted to assess the affinity and selectivity of BerEp4 antibody and assess its possible use in designing theranostic probes for BCC. We provide evidence that our photon-counting fluorescence macrodetection system can recover specific signal increases from a film/pellet phantom. Additionally, we show that a two-photon excited fluorescence /backscatter confocal microscopy system can image BerEP4 antibody/antigen complex on the surface of BerEP4-expressing cancer cells in three dimensions. Based on the initial results, BerEP4 seems to be a promising biomarker for molecular imaging of BCC. To prepare BerEP4 for eventual theranostic use, we examined the feasibility of a combined macro-/micro-optical approach to imaging BCC with various histologies. These optical methods, endowed with the ability to monitor treatment in real time, may open an opportunity for noninvasive diagnosis, treatments, and follow-up.


Asunto(s)
Biomarcadores de Tumor/metabolismo , Carcinoma Basocelular/diagnóstico por imagen , Neoplasias Cutáneas/diagnóstico por imagen , Anticuerpos Monoclonales , Carcinoma Basocelular/metabolismo , Línea Celular Tumoral , Humanos , Microscopía Confocal , Fantasmas de Imagen , Proyectos Piloto , Cintigrafía , Neoplasias Cutáneas/metabolismo
5.
iScience ; 26(11): 108140, 2023 Nov 17.
Artículo en Inglés | MEDLINE | ID: mdl-37915592

RESUMEN

Intracortical microstimulation (ICMS) has been used for the development of brain machine interfaces. However, further understanding about the spatiotemporal responses of neurons to different electrical stimulation parameters is necessary to inform the design of optimal therapies. In this study, we employed in vivo electrophysiological recording, two-photon calcium imaging, and electric field simulation to evaluate the acute effect of ICMS on layer II/III neurons. Our results show that stimulation frequency non-linearly modulates neuronal responses, whereas the magnitude of responses is linearly correlated to the electric field strength and stimulation amplitude before reaching a steady state. Temporal dynamics of neurons' responses depends more on stimulation frequency and their distance to the stimulation electrode. In addition, amplitude-dependent post-stimulation suppression was observed within ∼500 µm of the stimulation electrode, as evidenced by both calcium imaging and local field potentials. These findings provide insights for selecting stimulation parameters to achieve desirable spatiotemporal specificity of ICMS.

6.
Mol Imaging ; 11(3): 177-86, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22554482

RESUMEN

Human epidermal growth factor receptor type 2 (HER2) is a well-known biomarker that is overexpressed in many breast carcinomas. HER2 expression level is an important factor to optimize the therapeutic strategy and monitor the treatment. We used albumin binding domain-fused HER2-specific Affibody molecules, labeled with Alexa Fluor750 dye, to characterize HER2 expression in vivo. Near-infrared optical imaging studies were carried out using mice with subcutaneous HER2-positive tumors. Animals were divided into groups of five: no treatment and 12 hours and 1 week after treatment of the tumors with the Hsp90 inhibitor 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG). The compartmental ligands-receptor model, describing binding kinetics, was used to evaluate HER2 expression from the time sequence of the fluorescence images after the intravenous probe injection. The normalized rate of accumulation of the specific fluorescent biomarkers, estimated from this time sequence, linearly correlates with the conventional ex vivo enzyme-linked immunosorbent assay (ELISA) readings for the same tumor. Such correspondence makes properly arranged fluorescence imaging an excellent candidate for estimating HER2 overexpression in tumors, complementing ELISA and other ex vivo assays. Application of this method to the fluorescence data from HER2-positive xenografts reveals that the 17-DMAG treatment results in downregulation of HER2. Application of the AngioSense 750 probe confirmed the antiangiogenic effect of 17-DMAG found with Affibody-Alexa Fluor 750 conjugate.


Asunto(s)
Genes erbB-2 , Espectrometría de Fluorescencia/métodos , Animales , Benzoquinonas/farmacología , Línea Celular Tumoral , Ensayo de Inmunoadsorción Enzimática , Femenino , Proteínas HSP90 de Choque Térmico/antagonistas & inhibidores , Lactamas Macrocíclicas/farmacología , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Neoplasias Experimentales/irrigación sanguínea , Neoplasias Experimentales/tratamiento farmacológico
7.
Radiology ; 256(2): 367-78, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20571122

RESUMEN

PURPOSE: To investigate the potential role of optical tomography in the near-infrared (NIR) spectrum with ultrasonographic (US) localization as a means of differentiating early-stage cancers from benign lesions of the breast. MATERIALS AND METHODS: The protocol was approved by the institutional review boards and was HIPAA compliant; all participants signed an informed consent. One hundred seventy-eight consecutive women (mean age, 52 years; range, 21-89 years) who underwent US-guided biopsy were imaged with a hand-held probe consisting of a coregistered US transducer and an NIR imager. The lesion location provided by coregistered US was used to guide optical imaging. Light absorption was measured at two optical wavelengths. From this measurement, tumor angiogenesis was assessed on the basis of calculated total hemoglobin concentration (tHb) and was correlated with core biopsy results. For patients diagnosed with carcinomas and followed up with subsequent excision, the tHb was correlated with pathologic parameters. RESULTS: There were two in situ carcinomas (Tis), 35 T1 carcinomas, 24 T2-T4 carcinomas, and 114 benign lesions. The mean maximum and mean average tHb of the Tis-T1 group were 102.0 micromol/L +/- 28.5 (standard deviation) and 71.9 micromol/L +/- 18.8, and those of the T2-T4 group were 100.3 micromol/L +/- 26.4 and 67.0 micromol/L +/- 18.3, respectively. The mean maximum and mean average tHb of the benign group were 55.1 micromol/L +/- 22.7 and 39.1 micromol/L +/- 14.9, respectively. Both mean maximum and mean average tHb levels were significantly higher in the malignant groups than they were in the benign group (P < .001). The sensitivity, specificity, positive predictive value, and negative predictive value for Tis-T1 cancers were 92%, 93%, 81%, and 97%. The corresponding values for T2-T4 tumors were 75%, 93%, 69%, and 95%. CONCLUSION: The angiogenesis (tHb) contrast imaged by using the NIR technique with US holds promise as an adjunct to mammography and US for distinguishing early-stage invasive breast cancers from benign lesions.


Asunto(s)
Neoplasias de la Mama/diagnóstico , Técnica de Sustracción , Tomografía Óptica/métodos , Ultrasonografía Mamaria/métodos , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Factibilidad , Femenino , Humanos , Persona de Mediana Edad , Invasividad Neoplásica , Estadificación de Neoplasias , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
8.
J Biomed Opt ; 13(6): 064029, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-19123675

RESUMEN

We develop a new tomographic imaging reconstruction algorithm for a two-layer tissue structure. Simulations and phantom experiments show more accurate reconstruction of target optical properties compared with those results obtained from a semi-infinite tissue model for layered structures. This improvement is mainly attributed to the more accurate estimation of background optical properties and more accurate estimation of weight matrix for imaging reconstruction by considering the light propagation effect in the second layer. Clinical results of breast lesions are also presented to demonstrate the utility of this new imaging algorithm.


Asunto(s)
Algoritmos , Neoplasias de la Mama/patología , Mama/patología , Aumento de la Imagen/métodos , Interpretación de Imagen Asistida por Computador/métodos , Pared Torácica/patología , Tomografía Óptica/métodos , Artefactos , Femenino , Humanos , Persona de Mediana Edad , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
9.
EJNMMI Res ; 8(1): 26, 2018 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-29619584

RESUMEN

BACKGROUND: Assessment of the status of tumor biomarkers in individual patients would facilitate personalizing treatment strategy, and continuous monitoring of those biomarkers and their binding process to the therapeutic drugs would provide a means for early evaluation of the efficacy of therapeutic intervention. Fluorescent probes can accumulate inside the tumor region due to the leakiness of its vascularization and this can make it difficult to distinguish if the measured fluorescence intensity is from probes bound to target receptors or just accumulated unbound probes inside the tumor. In this paper, we have studied the fluorescence lifetime as a means to distinguish bound HER2 specific affibody probes to HER2 receptors. Our imaging system is a time-resolved fluorescence system using a Ti-Sapphire femtosecond pulse laser as source and Time correlated Single photon Counting (TCSPC) system as detector for calculating the lifetime of the contrast agent. HER2-specific Affibody (His6-ZHER2:GS-Cys) (Affibody, Stockholm, Sweden) conjugated with a Dylight750 fluorescent probe (Thermo-Fisher-Scientific, Waltham, Massachusetts) was used as contrast agent and six human cancer cell lines, BT-474, SKOV-3, NCI-N87, MDA-MB-361, MCF-7, and MDA-MB-468, known to express different levels of HER2/neu, are used in athymic mice xenografts. RESULTS: By comparing the lifetime of unbound contrast agent (at the contralateral site) to the fluorescence lifetime at the tumor site, our results show that the fluorescence lifetime decreases as HER2 specific Affibody probes bind to the tumor receptors. A decrease of ~15% (100ps) in tumor fluorescence lifetime was observed in tumors with mid to high HER2 expression. Smaller decreases were observed in tumors with low-level of HER2 receptors and no change was observed in the non-HER2-expressing tumors. CONCLUSIONS: Using HER2-specific Affibody conjugated with the Dylight750 fluorescent probe as contrast agent, we demonstrated in live animals that change in fluorescence lifetime of the bound contrast agent can be used to assess the high to mid-level expression of HER2 expressing tumors in-vivo in only one measurement. The rationale is that the fluorescence lifetime of our specific probe is sensitive to affinity to, and specific interaction with, other molecules.

10.
Brain Behav ; 5(7): e00335, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-26221569

RESUMEN

BACKGROUND: A novel feature extraction technique, Relative-Brain-Signature (RBS), which characterizes subjects' relationship to populations with distinctive neuronal activity, is presented. The proposed method transforms a set of Electroencephalography's (EEG) time series in high dimensional space to a space of fewer dimensions by projecting time series onto orthogonal subspaces. METHODS: We apply our technique to an EEG data set of 77 abstinent alcoholics and 43 control subjects. To characterize subjects' relationship to the alcoholic and control populations, one RBS vector with respect to the alcoholic and one with respect to the control population is constructed. We used the extracted RBS vectors to identify functional biomarkers over the brain of alcoholics. To achieve this goal, the classification algorithm was used to categorize subjects into alcoholics and controls, which resulted in 78% accuracy. RESULTS AND CONCLUSIONS: Using the results of the classification, regions with distinctive functionality in alcoholic subjects are detected. These affected regions, with respect to their spatial extent, are frontal, anterior frontal, centro-parietal, parieto-occiptal, and occipital lobes. The distribution of these regions over the scalp indicates that the impact of the alcohol in the cerebral cortex of the alcoholics is spatially diffuse. Our finding suggests that these regions engage more of the right hemisphere relative to the left hemisphere of the alcoholics' brain.


Asunto(s)
Alcoholismo/fisiopatología , Algoritmos , Encéfalo/fisiopatología , Electroencefalografía/métodos , Adulto , Alcoholismo/clasificación , Mapeo Encefálico , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Procesamiento de Señales Asistido por Computador , Percepción Visual/fisiología , Adulto Joven
11.
J Clin Endocrinol Metab ; 100(10): 3928-33, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26301943

RESUMEN

CONTEXT: Facial plethora is a clinical sign described since ancient times for a variety of diseases. In the 19th century, it was linked to increased blood volume or flow, but this has never been proven. Facial plethora is also one of the earliest described clinical features of Cushing's syndrome (CS). OBJECTIVE: This study aimed to quantify facial plethora changes in CS as an early assessment of cure after surgery using noninvasive near-infrared multispectral imaging (MSI). DESIGN: The longitudinal cohort study was initiated in August 2012 and completed in August 2014. SETTING: Clinical research hospital, National Institutes of Health. PATIENTS: Thirty-four of the 38 patients who received surgical treatment for CS under protocol 97CH0076 during this period were included. INTERVENTION(S): MSI was performed on the right cheek of patients before surgery and 4.9 ± 3.1 days afterward. MAIN OUTCOME MEASURE(S): Average blood volume fraction as measured by MSI and serum cortisol. RESULTS: All but four of the 28 patients (86%) who were assessed as cured by postoperative plasma cortisol measurements of < 3 µg/dL showed a decrease in blood volume fraction (17.7 ± 0.03 vs 15.8 ± 0.03%; P = .0019), whereas an increase was seen in patients with persistent CS (18.5 ± 0.03 vs 21.4 ± 0.04%; P = .0017). Change in blood volume fraction before and after surgery was correlated with postoperative cortisol (rs = 0.58; P = .0003). CONCLUSIONS: Clinical data obtained from 34 patients indicate that a decrease in facial plethora after surgery, as evidenced by a decrease in blood volume fraction, is correlated with CS outcome. This novel technology for the first time identified a physiological mechanism associated with an ancient clinical sign. Furthermore, as a proof of principle, MSI is a promising early marker of cure in patients with CS that complements biochemical and clinical data.


Asunto(s)
Síndrome de Cushing/diagnóstico , Espectroscopía Infrarroja Corta , Adolescente , Hormona Adrenocorticotrópica/sangre , Adulto , Biomarcadores , Niño , Síndrome de Cushing/sangre , Síndrome de Cushing/cirugía , Femenino , Humanos , Hidrocortisona/sangre , Estudios Longitudinales , Masculino , Resultado del Tratamiento , Adulto Joven
12.
Technol Cancer Res Treat ; 13(5): 427-34, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24000992

RESUMEN

HER2 overexpression and amplification of the HER2/neu gene have been found in approximately 25% of invasive breast carcinomas. They are associated with a poor prognosis and resistance to therapy in breast cancer patients. Up to now, clinical evaluation of human epidermal growth factor receptor 2 (HER2) expression is based on ex vivo methods (immunohistochemistry (IHC) or fluorescence in situ hybridization (FISH) staining of biopsied tissue). Our goal is to realize "image and treat" paradigm using targeted fluorescent probes to evaluate expression levels of cell biomarkers responsible for cancer progression and to monitor the efficacy of corresponding monoclonal antibody treatments. We used fluorescent Affibody-based probes for in vivo analysis of HER2 receptors using near-infrared optical imaging that do not interfere with binding of the therapeutic agents to these receptors. We have analyzed two types of breast carcinoma xenografts with significant differences in HER2 expression (31 and 21 according to classification) in the mouse model. Using our kinetic model to analyze the temporal variations of the fluorescence intensity in the tumor area after two subsequent injections allowed us to assess quantitatively the difference in HER2 expression levels for two tumor types (BT-474 and MD-MBA-361). This result was substantiated by ELISA ex vivo assays of HER2 expression in the same tumors.


Asunto(s)
Neoplasias de la Mama/diagnóstico , Colorantes Fluorescentes , Receptor ErbB-2/metabolismo , Animales , Neoplasias de la Mama/metabolismo , Línea Celular Tumoral , Femenino , Colorantes Fluorescentes/administración & dosificación , Humanos , Inyecciones Intravenosas , Ratones Desnudos , Trasplante de Neoplasias , Espectroscopía Infrarroja Corta
13.
Clin Cancer Res ; 20(13): 3531-9, 2014 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-24671949

RESUMEN

PURPOSE: Advances in tumor biology created a foundation for targeted therapy aimed at inactivation of specific molecular mechanisms responsible for cell malignancy. In this paper, we used in vivo fluorescence lifetime imaging with HER2-targeted fluorescent probes as an alternative imaging method to investigate the efficacy of targeted therapy with 17-DMAG (an HSP90 inhibitor) on tumors with high expression of HER2 receptors. EXPERIMENTAL DESIGN: HER2-specific Affibody, conjugated to Alexafluor 750, was injected into nude mice bearing HER2-positive tumor xenograft. The fluorescence lifetime was measured before treatment and monitored after the probe injections at 12 hours after the last treatment dose, when the response to the 17-DMAG therapy was the most pronounced as well as a week after the last treatment when the tumors grew back almost to their pretreatment size. RESULTS: Imaging results showed significant difference between the fluorescence lifetimes at the tumor and the contralateral site (∼0.13 ns) in the control group (before treatment) and 7 days after the last treatment when the tumors grew back to their pretreatment dimensions. However, at the time frame that the treatment had its maximum effect (12 hours after the last treatment), the difference between the fluorescence lifetime at the tumor and contralateral site decreased to 0.03 ns. CONCLUSIONS: The results showed a good correlation between fluorescence lifetime and the efficacy of the treatment. These findings show that in vivo fluorescence lifetime imaging can be used as a promising molecular imaging tool for monitoring the treatment outcome in preclinical models and potentially in patients.


Asunto(s)
Neoplasias de la Mama/diagnóstico , Fluorescencia , Imagen Molecular , Animales , Benzoquinonas/administración & dosificación , Benzoquinonas/metabolismo , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/metabolismo , Línea Celular Tumoral , Modelos Animales de Enfermedad , Femenino , Proteínas HSP90 de Choque Térmico/antagonistas & inhibidores , Proteínas HSP90 de Choque Térmico/metabolismo , Xenoinjertos , Humanos , Rayos Infrarrojos , Lactamas Macrocíclicas/administración & dosificación , Lactamas Macrocíclicas/metabolismo , Ratones , Receptor ErbB-2/antagonistas & inhibidores , Receptor ErbB-2/metabolismo , Proteínas Recombinantes de Fusión/administración & dosificación , Proteínas Recombinantes de Fusión/metabolismo , Factores de Tiempo
14.
Front Neurosci ; 8: 393, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25565935

RESUMEN

Cerebral hemodynamics reflect cognitive processes and underlying physiological processes, both of which are captured by functional near infrared spectroscopy (fNIRS). Here, we introduce a novel parameter of Oxygenation Variability directly obtained from fNIRS data -the OV Index-and we demonstrate its use in children. fNIRS data were collected from 17 children (ages 4-8 years), while they performed a standard Go/No-Go task. Data were analyzed using two frequency bands-the first attributed to cerebral autoregulation (CA) (<0.1 Hz) and the second to respiration (0.2-0.3 Hz). Results indicate differences in variability of oscillations of oxygen saturation (SO2) between the two different bands. These pilot data reveal a dynamic relationship between chronological age and OV index in CA associated frequency of <0.1 Hz. Specifically, OV index increased with age between 4 and 6 years. In addition, there was much higher variability in frequencies associated with CA than for respiration across subjects. These findings provide preliminary evidence for the utility of the OV index and are the first to describe the relationship between cerebral autoregulation and age in children using fNIRS methodology.

15.
Stud Health Technol Inform ; 185: 265-97, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23542939

RESUMEN

In vivo optical imaging is being conducted in a variety of medical applications, including optical breast cancer imaging, functional brain imaging, endoscopy, exercise medicine, and monitoring the photodynamic therapy and progress of neoadjuvant chemotherapy. In the past three decades, in vivo diffuse optical breast cancer imaging has shown promising results in cancer detection, and monitoring the progress of neoadjuvant chemotherapy. The use of near infrared spectroscopy for functional brain imaging has been growing rapidly. In fluorescence imaging, the difference between autofluorescence of cancer lesions compared to normal tissues were used in endoscopy to distinguish malignant lesions from normal tissue or inflammation and in determining the boarders of cancer lesions in surgery. Recent advances in drugs targeting specific tumor receptors, such as monoclonal antibodies (mAb), has created a new demand for developing non-invasive in vivo imaging techniques for detection of cancer biomarkers, and for monitoring their down regulations during therapy. Targeted treatments, combined with new imaging techniques, are expected to potentially result in new imaging and treatment paradigms in cancer therapy. Similar approaches can potentially be applied for the characterization of other disease-related biomarkers. In this chapter, we provide a review of diffuse optical and fluorescence imaging techniques with their application in functional brain imaging and cancer diagnosis.


Asunto(s)
Mapeo Encefálico/métodos , Microscopía Fluorescente/métodos , Imagen Molecular/métodos , Análisis Espectral/métodos , Animales , Humanos , Relación Estructura-Actividad
16.
PLoS One ; 8(12): e83887, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24386302

RESUMEN

Diffuse multi-spectral imaging has been evaluated as a potential non-invasive marker of tumor response. Multi-spectral images of Kaposi sarcoma skin lesions were taken over the course of treatment, and blood volume and oxygenation concentration maps were obtained through principal component analysis (PCA) of the data. These images were compared with clinical and pathological responses determined by conventional means. We demonstrate that cutaneous lesions have increased blood volume concentration and that changes in this parameter are a reliable indicator of treatment efficacy, differentiating responders and non-responders. Blood volume decreased by at least 20% in all lesions that responded by clinical criteria and increased in the two lesions that did not respond clinically. Responses as assessed by multi-spectral imaging also generally correlated with overall patient clinical response assessment, were often detectable earlier in the course of therapy, and are less subject to observer variability than conventional clinical assessment. Tissue oxygenation was more variable, with lesions often showing decreased oxygenation in the center surrounded by a zone of increased oxygenation. This technique could potentially be a clinically useful supplement to existing response assessment in KS, providing an early, quantitative, and non-invasive marker of treatment effect.


Asunto(s)
Imagen Molecular , Sarcoma de Kaposi/tratamiento farmacológico , Neoplasias Cutáneas/tratamiento farmacológico , Adulto , Volumen Sanguíneo/efectos de los fármacos , Humanos , Persona de Mediana Edad , Oxígeno/metabolismo , Análisis de Componente Principal , Sarcoma de Kaposi/metabolismo , Sarcoma de Kaposi/fisiopatología , Neoplasias Cutáneas/metabolismo , Neoplasias Cutáneas/fisiopatología , Resultado del Tratamiento
17.
Anal Cell Pathol (Amst) ; 35(5-6): 317-37, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22433452

RESUMEN

In vivo optical imaging is being conducted in a variety of medical applications, including optical breast cancer imaging, functional brain imaging, endoscopy, exercise medicine, and monitoring the photodynamic therapy and progress of neoadjuvant chemotherapy. In the past three decades, in vivo diffuse optical breast cancer imaging has shown promising results in cancer detection, and monitoring the progress of neoadjuvant chemotherapy. The use of near infrared spectroscopy for functional brain imaging has been growing rapidly. In fluorescence imaging, the difference between autofluorescence of cancer lesions compared to normal tissues were used in endoscopy to distinguish malignant lesions from normal tissue or inflammation and in determining the boarders of cancer lesions in surgery. Recent advances in drugs targeting specific tumor receptors, such as AntiBodies (MAB), has created a new demand for developing non-invasive in vivo imaging techniques for detection of cancer biomarkers, and for monitoring their down regulations during therapy. Targeted treatments, combined with new imaging techniques, are expected to potentially result in new imaging and treatment paradigms in cancer therapy. Similar approaches can potentially be applied for the characterization of other disease-related biomarkers. In this chapter, we provide a review of diffuse optical and fluorescence imaging techniques with their application in functional brain imaging and cancer diagnosis.


Asunto(s)
Imagenología Tridimensional/métodos , Óptica y Fotónica/métodos , Animales , Encéfalo/patología , Encéfalo/fisiopatología , Fluorescencia , Humanos , Neoplasias/diagnóstico , Neoplasias/patología , Imagen Óptica
18.
PLoS One ; 7(7): e41016, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22911732

RESUMEN

PURPOSE: Amplification of the HER2/neu gene and/or overexpression of the corresponding protein have been identified in approximately 20% of invasive breast carcinomas. Assessment of HER2 expression in vivo would advance development of new HER2-targeted therapeutic agents and, potentially, facilitate choice of the proper treatment strategy offered to the individual patient. We present novel HER2-specific probes for in vivo evaluation of the receptor status by near-infrared (NIR) optical imaging. EXPERIMENTAL DESIGN: Affibody molecules were expressed, purified, and labeled with NIR-fluorescent dyes. The binding affinity and specificity of the obtained probe were tested in vitro. For in vivo validation, the relationship of the measured NIR signal and HER2 expression was characterized in four breast cancer xenograft models, expressing different levels of HER2. Accumulation of Affibody molecules in tumor tissue was further confirmed by ex vivo analysis. RESULTS: Affibody-DyLight conjugates showed high affinity to HER2 (K(D) = 3.66±0.26). No acute toxicity resulted from injection of the probes (up to 0.5 mg/kg) into mice. Pharmacokinetic studies revealed a relatively short (37.53±2.8 min) half-life of the tracer in blood. Fluorescence accumulation in HER2-positive BT-474 xenografts was evident as soon as a few minutes post injection and reached its maximum at 90 minutes. On the other hand, no signal retention was observed in HER2-negative MDA-MB-468 xenografts. Immunostaining of extracted tumor tissue confirmed penetration of the tracer into tumor tissue. CONCLUSIONS: The results of our studies suggest that Affibody-DyLight-750 conjugate is a powerful tool to monitor HER2 status in a preclinical setting. Following clinical validation, it might provide complementary means for assessment of HER2 expression in breast cancer patients (assuming availability of proper NIR scanners) and/or be used to facilitate detection of HER2-positive metastatic lesions during NIR-assisted surgery.


Asunto(s)
Neoplasias de la Mama/diagnóstico , Neoplasias de la Mama/metabolismo , Imagen Óptica , Receptor ErbB-2/metabolismo , Proteínas Recombinantes de Fusión/metabolismo , Secuencia de Aminoácidos , Animales , Línea Celular Tumoral , Femenino , Fluorescencia , Humanos , Ligandos , Ratones , Datos de Secuencia Molecular , Unión Proteica , Proteínas Recombinantes de Fusión/administración & dosificación , Proteínas Recombinantes de Fusión/química , Trasplante Heterólogo
19.
PLoS One ; 7(2): e31881, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22384092

RESUMEN

One of the most important factors in choosing a treatment strategy for cancer is characterization of biomarkers in cancer cells. Particularly, recent advances in Monoclonal Antibodies (MAB) as primary-specific drugs targeting tumor receptors show that their efficacy depends strongly on characterization of tumor biomarkers. Assessment of their status in individual patients would facilitate selection of an optimal treatment strategy, and the continuous monitoring of those biomarkers and their binding process to the therapy would provide a means for early evaluation of the efficacy of therapeutic intervention. In this study we have demonstrated for the first time in live animals that the fluorescence lifetime can be used to detect the binding of targeted optical probes to the extracellular receptors on tumor cells in vivo. The rationale was that fluorescence lifetime of a specific probe is sensitive to local environment and/or affinity to other molecules. We attached Near-InfraRed (NIR) fluorescent probes to Human Epidermal Growth Factor 2 (HER2/neu)-specific Affibody molecules and used our time-resolved optical system to compare the fluorescence lifetime of the optical probes that were bound and unbound to tumor cells in live mice. Our results show that the fluorescence lifetime changes in our model system delineate HER2 receptor bound from the unbound probe in vivo. Thus, this method is useful as a specific marker of the receptor binding process, which can open a new paradigm in the "image and treat" concept, especially for early evaluation of the efficacy of the therapy.


Asunto(s)
Biomarcadores de Tumor/metabolismo , Receptor ErbB-2/metabolismo , Animales , Anticuerpos Monoclonales/metabolismo , Línea Celular Tumoral , Epítopos/química , Femenino , Fluorescencia , Humanos , Concentración de Iones de Hidrógeno , Inmunohistoquímica/métodos , Ratones , Ratones Desnudos , Microscopía Confocal/métodos , Trasplante de Neoplasias , Programas Informáticos , Espectroscopía Infrarroja Corta/métodos , Factores de Tiempo
20.
Biomed Opt Express ; 3(1): 192-205, 2012 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-22254179

RESUMEN

In this paper we discuss results based on using instrumental motion as a signal rather than treating it as noise in Near Infra-Red (NIR) imaging. As a practical application to demonstrate this approach we show the design of a novel NIR hematoma detection device. The proposed device is based on a simplified single source configuration with a dual separation detector array and uses motion as a signal for detecting changes in blood volume in the dural regions of the head. The rapid triage of hematomas in the emergency room will lead to improved use of more sophisticated/expensive imaging facilities such as CT/MRI units. We present simulation results demonstrating the viability of such a device and initial phantom results from a proof of principle device. The results demonstrate excellent localization of inclusions as well as good quantitative comparisons.

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