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BACKGROUND: Endobronchial Ultrasound-guided Transbronchial Needle Aspiration (EBUS-TBNA) has revolutionized the diagnostic approach to mediastinal diseases. Lesions located lateral to the pulmonary artery (trans-PA, Station 5), or in the lumen of the PA (intra-PA) are in the 'blind-spot' of EBUS. OBJECTIVES: We describe a case series where EBUS guided trans-pulmonary or intra-pulmonary aspiration (EBUS-TIPNA) was used for diagnosis. METHODS: Retrospective analysis of 10 patients who had EBUS-TIPNA over 3 years in 2 centres. The inclusion criteria included patients with station 5 lesions, or intrapulmonary artery lesions, where no other option was possible. RESULTS: The study included 4 males and 6 females, mean age 52 years, with 7 trans-PA and 3 intra-PA lesions. Adequacy was seen in 10/10, and a definitive diagnosis was made in 9/10 patients. There were no procedure-related complications. CONCLUSION: EBUS-TIPNA can be done as a safe and successful procedure and adds to the armamentarium of Convex Probe-EBUS (CP-EBUS), in carefully selected patients.
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Biopsia por Aspiración con Aguja Fina Guiada por Ultrasonido Endoscópico/métodos , Pulmón/patología , Arteria Pulmonar/patología , Ultrasonografía/instrumentación , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Biopsia Guiada por Imagen/métodos , Pulmón/irrigación sanguínea , Neoplasias Pulmonares/patología , Ganglios Linfáticos/patología , Masculino , Enfermedades del Mediastino/diagnóstico por imagen , Enfermedades del Mediastino/patología , Mediastino/patología , Persona de Mediana Edad , Estudios Retrospectivos , Tomografía Computarizada por Rayos X/métodos , Ultrasonografía/métodosRESUMEN
BACKGROUND: Prolonged air leak (PAL) is a life-threatening condition that can present either as bronchopleural fistula, or alveolar-pleural fistula (APF). Although numerous bronchoscopic treatments are described, they are either expensive, not widely available in the developing world or have limited success. We describe our experience with a novel customized endobronchial silicone blocker (CESB) for PAL treatment. METHODS: This is a retrospective study of PAL patients who underwent CESB placement. The air leak was localized using a balloon occlusion test. The CESB was uniquely designed by molding silicone stent pieces into a conical shape, deployed with rigid bronchoscopy into the appropriate segment, and reinforced with cyanoacrylate glue to prevent migration. In patients with APF, pleurodesis was performed after leak resolution to prevent recurrence. Following this, the CESB was removed after 6 weeks. RESULTS: Forty-nine CESBs were placed in 31 patients (25 male individuals, 6 female individuals) with mean age of 49.7±19.7 years. The PALs included APF (n=16), bronchopleural fistula (n=14), and airway-mediastinal fistula (n=1). The average diameter of the CESB used was 7.9±2.9 mm. There was resolution of the PAL in 26 of 31 patients (84%). The CESB migrated in 5 patients with no adverse events. Pleurodesis was performed in 13 of 16 patients with APF, to prevent recurrence. No other significant complications were observed. CONCLUSIONS: CESBs represent a safe, effective, and innovative approach in the management of PAL. They should be considered in patients who are not surgical candidates, fail surgery, or those who have a recurrence following surgery.
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Fístula Bronquial/prevención & control , Enfermedades Pleurales/prevención & control , Prótesis e Implantes , Siliconas , Broncoscopía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias , Estudios RetrospectivosRESUMEN
BACKGROUND: Current histopathological classification and TNM staging have limited accuracy in predicting survival and stratifying patients for appropriate treatment. The goal of the study is to determine whether the expression pattern of functionally important regulatory proteins can add additional values for more accurate classification and prognostication of non-small lung cancer (NSCLC). METHODS: The expression of 108 proteins and phosphoproteins in 30 paired NSCLC samples were assessed using Protein Pathway Array (PPA). The differentially expressed proteins were further confirmed using a tissue microarray (TMA) containing 94 NSCLC samples and were correlated with clinical data and survival. RESULTS: Twelve of 108 proteins (p-CREB(Ser133), p-ERK1/2(Thr202/Tyr204), Cyclin B1, p-PDK1(Ser241), CDK4, CDK2, HSP90, CDC2p34, ß-catenin, EGFR, XIAP and PCNA) were selected to build the predictor to classify normal and tumor samples with 97% accuracy. Five proteins (CDC2p34, HSP90, XIAP, CDK4 and CREB) were confirmed to be differentially expressed between NSCLC (n=94) and benign lung tumor (n=19). Over-expression of CDK4 and HSP90 in tumors correlated with a favorable overall survival in all NSCLC patients and the over-expression of p-CREB(Ser133) and CREB in NSCLC correlated with a favorable survival in smokers and those with squamous cell carcinoma, respectively. Finally, the four proteins (CDK4, HSP90, p-CREB and CREB) were used to calculate the risk score of each individual patient with NSCLC to predict survival. CONCLUSION: In summary, our data demonstrated a broad disturbance of functionally important regulatory proteins in NSCLC and some of these can be selected as clinically useful biomarkers for diagnosis, classification and prognosis.
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Dedicated linear endobronchial ultrasound (EBUS) is an established modality in sampling central pulmonary lesions, mediastinal and hilar lymph nodes to diagnose and stage lung malignancies as well as evaluate a number of inflammatory conditions. In addition, power Doppler modality of EBUS allows for vascular evaluation. We describe a case where EBUS visualized a submucosal lesion within a vascular malformation, which was eventually proven to be a carcinoid tumor. Computed tomographic scan of the chest failed to differentiate the 2 structures and bronchoscopy showed no endobronchial component. This case underscores the added diagnostic capabilities of endobronchial Doppler ultrasonography. We suggest considering EBUS in investigating central opacities associated with vascular features within the lung parenchyma when technically feasible.
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Neoplasias de los Bronquios/diagnóstico por imagen , Tumor Carcinoide/diagnóstico por imagen , Endosonografía/métodos , Hallazgos Incidentales , Ultrasonografía Doppler/métodos , Malformaciones Vasculares/diagnóstico por imagen , Neoplasias de los Bronquios/complicaciones , Broncoscopía , Tumor Carcinoide/complicaciones , Diagnóstico Diferencial , Humanos , Masculino , Persona de Mediana Edad , Tomografía Computarizada por Rayos X , Malformaciones Vasculares/complicacionesRESUMEN
Endobronchial stents have been used occasionally to treat benign conditions such as tracheobronchomalacia (TBM). This report describes a unique case of a patient with crescentic TBM in whom Dynamic Y stent was placed on 2 separate occasions to control symptoms and resulted in identical posterior wall stent fractures within a year of stent placement, both times. A silicone Y stent was substituted for the dynamic stent, and it has been effective in controlling symptoms for 9 months without complications. A literature review of cases of fractured Dynamic Y stents is made and factors affecting the choice of stent type for crescentic TBM are explored.
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Falla de Prótesis , Stents/efectos adversos , Traqueobroncomalacia/terapia , Humanos , Masculino , Persona de Mediana Edad , Diseño de Prótesis/efectos adversos , Factores de Riesgo , Siliconas/uso terapéutico , Tomografía Computarizada por Rayos X , Traqueobroncomalacia/diagnóstico por imagen , Resultado del TratamientoRESUMEN
Chronic Obstructive Pulmonary Disease (COPD) frequently has a significant impact on patients' everyday activity. Because of this, accurate measurement of daily activity is of particular interest. Although accelerometers are an objective means of measuring daily activity, these devices sense vibrations and erroneously score motor vehicle travel (MVT) as moderate physical activity. It is the objective of this study to develop a new method to analyze accelerometry data that would accurately classify MVT as non-acceleration, or sitting/standing. As sitting/standing has a different pattern of count-to-count variability than walking, we hypothesized that a rolling standard deviation (RSD), which is a measurement of volatility in the data, would more accurately classify periods of MVT than analysis based on activity counts alone. Twenty-two subjects with COPD were studied. A training set of 15% of the dataset was used to establish an RSD-threshold during MVT based on the upper 95%-confidence interval. The accuracy of the RSD thresholds were tested and presented as sensitivity, specificity and receiver operating curves. Results demonstrated high sensitivity and specificity suggesting that the RSD not only accurately classified MVT, but had a low rate of misclassification. The RSD analysis scored more MVT as sitting/standing than assessment by VMU alone. The accuracy of accelerometers to define the profile of daily activity in sedentary populations, such as those with COPD, is greatly improved.
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Acelerometría , Actividades Cotidianas , Monitoreo Ambulatorio/instrumentación , Actividad Motora/fisiología , Vehículos a Motor , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Ejercicio Físico , Femenino , Humanos , Masculino , Curva ROC , Sensibilidad y Especificidad , Viaje , CaminataRESUMEN
Sphingomyelin (SM), a major sphingolipid in the lipid raft microdomains of the cell membrane, is synthesized by plasma membrane-bound sphingomyelin synthase 2 (SMS2). SMS2 is required for the maintenance of plasma membrane microdomain fluidity and receptor-mediated responses to inflammation in macrophages. However, the exact mechanism of SMS2 activation in endothelial barrier disruption and lung injury is not fully understood. To define the role of SMS activation in lung injury, we hypothesized that the inhibition of SM synthesis may provide protection against acute lung injury (ALI) by preserving endothelial barrier function. Using SMS2-silencing RNA (siRNA) treatment in human pulmonary endothelial cells (HPAECs) and tricyclodecan-9-yl-xanthogenate (D609), a competitive inhibitor of SMS, and phosphatidylcholine-specific phospholipase C in a murine model of bacterial LPS injury, we studied the role of sphingomyelin synthesis in ALI. Results show that pretreating mice with D609 significantly attenuated LPS-induced lung injury, as measured by a significant decrease in wet to dry ratio, bronchoalveolar lavage fluid cell and protein counts, and myeloperoxidase activity in lung tissue. Similarly, LPS-induced endothelial barrier disruption was significantly reduced in HPAECs pretreated with D609 or SMS2 siRNA, as demonstrated by an increase in paracellular integrity on an FITC-dextran assay, by the inhibition of LPS-induced stress fibers, and by the formation of cortical actin rings and lamellipodia at the periphery. These results indicate that D609 attenuates LPS-mediated endothelial barrier dysfunction and lung injury in mice through inhibition of SMS, suggesting a novel and essential role of SMS inhibition in modulating endothelial barrier integrity via actin cytoskeletal activation, with a potential therapeutic role in ALI.
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Hidrocarburos Aromáticos con Puentes/farmacología , Citoesqueleto/metabolismo , Células Endoteliales/metabolismo , Lesión Pulmonar/metabolismo , Arteria Pulmonar/metabolismo , Esfingomielinas/biosíntesis , Tionas/farmacología , Transferasas (Grupos de Otros Fosfatos Sustitutos)/metabolismo , Actinas/biosíntesis , Animales , Células Cultivadas , Humanos , Lipopolisacáridos/inmunología , Pulmón/irrigación sanguínea , Lesión Pulmonar/inducido químicamente , Ratones , Norbornanos , Interferencia de ARN , ARN Interferente Pequeño , Esfingomielinas/metabolismo , Tiocarbamatos , Transferasas (Grupos de Otros Fosfatos Sustitutos)/antagonistas & inhibidores , Transferasas (Grupos de Otros Fosfatos Sustitutos)/genética , Fosfolipasas de Tipo C/metabolismoRESUMEN
BACKGROUND: The frequency of oxygen desaturation during daily activities in chronic obstructive pulmonary disease (COPD) is poorly defined. The BODE index predicts survival in COPD. The purpose of this study was to determine the relationship between BODE scores and oxygen saturation during daily activities. METHODS: Seventy-eight patients with COPD (FEV(1) = 37%) underwent ambulatory oximetry and activity monitoring. We defined four activity categories: Walking, Slow-Intermittent-Walking (SIW), Active-Not-Walking (ANW), and Rest. We quantified oxygen desaturation during activity using a desaturation index (DSI = % time oxygen saturation <90%). BODE scores were categorized into three groups: group I (0-3), II (4-6), and III (7-10). RESULTS: The percentage of patients demonstrating oxygen desaturation (DSI ≥ 10%) during each activity was 55% for Walking, 35% for SIW, 15% for ANW, and 28% for Rest. There was a strong association between BODE score and desaturation for Walking and SIW. During Walking, 21, 44, and 86% of patients in BODE groups I, II, and III, respectively, demonstrated desaturation. The DSI for Walking and SIW was increased in patients in BODE groups II and III compared to group I (P < 0.006, P < 0.007, respectively). BODE score was also linked to long-term oxygen therapy (LTOT) usage; the majority of patients not on LTOT (89%) had a BODE score <7. The majority of patients on LTOT (84%) demonstrated desaturation during Walking, but 42% of patients not on LTOT also demonstrated desaturation. In this subgroup of patients not on LTOT, all patients with a BODE score ≥ 7 demonstrated desaturation during Walking. CONCLUSIONS: The link between the BODE index and oxygen desaturation during daily activities suggests that desaturation is linked to disease severity. Our data suggest that patients with a BODE score ≥ 7 should be evaluated for desaturation during daily activities. Use of the BODE index to screen for exertional desaturation may have value as a tool that can lead to the earlier identification of patients who may be candidates for LTOT.
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Actividades Cotidianas , Oxígeno/sangre , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Índice de Severidad de la Enfermedad , Anciano , Estudios de Cohortes , Humanos , Masculino , Persona de Mediana Edad , Oximetría , Oxígeno/uso terapéutico , Enfermedad Pulmonar Obstructiva Crónica/mortalidad , Caminata/fisiologíaRESUMEN
Sphingomyelin synthase (SMS) catalyzes the synthesis of sphingomyelin (SM) and is required for maintenance of plasma membrane microdomain fluidity. Of the two isoforms of mammalian SMS, SMS1 is mostly present in the trans-Golgi apparatus, whereas SMS2 is predominantly found at the plasma membrane. SMS2 has a role in receptor mediated response to inflammation in macrophages, however, the role of SMS2 in vascular permeability, pulmonary edema, and lung injury have not been investigated. To define the role of SMS activation in lung injury, we utilized a lipopolysaccharide (LPS)-induced lung edema model. SMS activity was measured and correlated with the severity of lung injury. Within 4 h of LPS treatment, SMS activity was increased significantly and remained upregulated up to 24 h. Comparison of LPS-induced lung injury in SMS2 knockout (SMS2(-/-)) and wild-type littermate control mice showed that inflammation, cytokine induction, and lung injury were significantly inhibited in SMS2(-/-) mice. Our results suggest that a deficiency of SMS2 can diminish the extent of pulmonary edema and lung injury. Furthermore, we show that depletion of SMS2 was sufficient to decrease MAP kinase-JNK activation, severity of LPS-induced pulmonary neutrophil influx, and inflammation, suggesting a novel role of SMS2 activation in lung injury.
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Lesión Pulmonar/enzimología , Lesión Pulmonar/patología , Transferasas (Grupos de Otros Fosfatos Sustitutos)/deficiencia , Actinas/metabolismo , Animales , Citoesqueleto/metabolismo , Células Endoteliales/enzimología , Células Endoteliales/patología , Activación Enzimática , Regulación Enzimológica de la Expresión Génica , Interleucina-6/metabolismo , Lipopolisacáridos , Pulmón/enzimología , Pulmón/patología , Lesión Pulmonar/inducido químicamente , Lesión Pulmonar/complicaciones , Ratones , Proteína Quinasa 8 Activada por Mitógenos/metabolismo , FN-kappa B/metabolismo , Neumonía/complicaciones , Neumonía/patología , ARN Mensajero/genética , ARN Mensajero/metabolismo , Esfingomielinas/biosíntesis , Factores de Tiempo , Transcripción Genética , Transferasas (Grupos de Otros Fosfatos Sustitutos)/antagonistas & inhibidores , Transferasas (Grupos de Otros Fosfatos Sustitutos)/genética , Transferasas (Grupos de Otros Fosfatos Sustitutos)/metabolismo , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
PURPOSE: Patients with chronic obstructive pulmonary disease with a low profile of daily activity have poor health outcomes. Although walking is a common activity, it may not be the most relevant physical activity to measure in this population. It was the purpose of this study to determine the accelerometer-defined thresholds that discriminate a range of daily activities and use these thresholds to assess activity profiles among stages of disease severity. METHODS: Subjects with chronic obstructive pulmonary disease (N = 57) completed a standardized sequence of activities that comprised sitting, standing, and walking while wearing an accelerometer on the waist and an actigraph on the wrist. Using a calibration procedure, accelerometer output was translated into speeds. Speeds were estimated for each interval in the testing sequence. Walking and nonacceleration thresholds were derived from the intervals to define 4 activity categories: walking, slow/intermittent walking, active-not-walking, and rest. Subjects wore the 2 devices for 2 days. Accelerometer output was then classified into 1 of the activity categories. Percent time spent in activity categories and speeds generated were compared among Global Initiative for Obstructive Lung Disease (GOLD) stages. RESULTS: The waist-worn accelerometer accurately estimated speeds. Speed thresholds for walking and nonacceleration were 0.70 mph and 0.25 mph, respectively. Among GOLD stages, those with more severe obstruction spent less time in the walking categories and generated slower speeds. CONCLUSIONS: The accuracy of these methods to detect a range of physical activities enhances the utility of accelerometers in comparing daily activity in sedentary populations. Measurements of the more subtle activities offer an appealing new area of study.
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Monitoreo Ambulatorio/instrumentación , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Caminata/fisiología , Aceleración , Anciano , Humanos , Índice de Severidad de la EnfermedadRESUMEN
Malignant primary tracheal tumors are extremely rare. The most common malignant primary tracheal tumors are squamous cell carcinoma and adenoid cystic carcinomas. In this brief report, we describe a patient who presented with a primary papillary squamous cell carcinoma in-situ at multiple areas in the trachea with a significant airway obstruction. Our case was successfully managed using a combination of electrocautery and argon photocoagulation for endotracheal ablation of the tumor and adjuvant external beam radiotherapy.
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Chronic obstructive pulmonary disease (COPD) is associated with significant morbidity and mortality. Its possible association with obstructive sleep apnea is a major cause of concern for clinicians. As the prevalence of both COPD and sleep apnea continues to rise, further investigation of this interaction is needed. In addition, COPD patients are at risk for hypoventilation during sleep due to the underlying respiratory dysfunction. In this study, 13 COPD subjects and 13 non-COPD control subjects were compared for the presence and severity of obstructive sleep apnea and nocturnal hypoventilation. All 26 subjects had presented to a sleep clinic and showed no signs of daytime hypoxemia. After matching for BMI and age, COPD subjects had a similar prevalence of sleep apnea with a lower degree of severity compared to the control subjects. However, less severe events, such as RERA, occurred at similar rates between the two groups. There was no significant difference between groups in the magnitude of oxyhemoglobin desaturation during sleep. Interestingly, severity and presence of nocturnal hypoxemia correlated with that of sleep apnea in the control group, but not in the COPD subjects. In conclusion, COPD without daytime hypoxemia was not a risk factor for sleep apnea or nocturnal hypoventilation in this study.
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Hipoventilación/diagnóstico , Hipoxia , Enfermedad Pulmonar Obstructiva Crónica/complicaciones , Apnea Obstructiva del Sueño/diagnóstico , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Ciudad de Nueva York , Índice de Severidad de la EnfermedadRESUMEN
Post-obstructive pneumonia is the result of airway obstruction, commonly due to lung cancer. The majority of patients with lung cancer are non-operable and incurable at initial presentation. The clinical course of these patients is steadily downhill with complicating events such as post-obstructive pneumonia, respiratory failure, pleural effusion, and severe debilitation. Non-invasive conventional options for post-obstructive pneumonia include broad-spectrum antibiotics, combined with attempts at relieving the obstruction using radiation therapy. There is scant literature on the natural course of post-obstructive pneumonia, disease resolution, and optimal treatment. With the recent surge in technologic advances in interventional pulmonology, multiple airway recanalizaton options are now available. In this paper, we describe the causes of post-obstructive pneumonia, and the role of interventional pulmonary procedures in -establishing an open airway.
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OBJECTIVE: Elevated plasma levels of endothelial microparticles (EMPs) are associated with the presence of clinical atherosclerosis. Considering the anti-inflammatory properties of HMG-CoA reductase inhibitors on the endothelium, we studied the effect of fluvastatin on the release of EMPs in cultured human coronary artery endothelial cells (HCAEC). METHODS AND RESULTS: EMPs were generated in TNF-alpha-activated HCAECs. The absolute number of EMPs was enumerated using a novel two-color flow cytometric immunostaining technique with TruCount beads as an internal reference. EMPs are defined as EC membrane vesicles (1-2 microm in size) with a characteristic immunophenotype. The addition of fluvastatin to TNF-alpha-activated HCAECs significantly suppressed EMP release. Fluvastatin suppressed TNF-alpha-induced Rho activation. The Rho-kinase inhibitor, Y-27632, reproduced the effect of statin. CONCLUSION: EMP release from TNF-alpha-activated HCAECs is suppressed by fluvastatin. In addition, the Rho/Rho-kinase may play an important role in modulating EMP release.
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Endotelio Vascular/efectos de los fármacos , Endotelio Vascular/metabolismo , Ácidos Grasos Monoinsaturados/farmacología , Indoles/farmacología , Glicoproteínas de Membrana/sangre , Glicoproteínas de Membrana/efectos de los fármacos , Proteínas Serina-Treonina Quinasas/metabolismo , Factor de Necrosis Tumoral alfa/farmacología , Antígenos CD , Arterias/efectos de los fármacos , Arterias/metabolismo , Células Cultivadas , Vasos Coronarios/efectos de los fármacos , Vasos Coronarios/metabolismo , Endoglina , Endotelio Vascular/citología , Activación Enzimática/efectos de los fármacos , Fluvastatina , Humanos , Integrina alfaV/metabolismo , Péptidos y Proteínas de Señalización Intracelular , Glicoproteínas de Membrana/inmunología , Tamaño de la Partícula , Receptores de Superficie Celular , Transducción de Señal/efectos de los fármacos , Transducción de Señal/fisiología , Molécula 1 de Adhesión Celular Vascular/metabolismo , Quinasas Asociadas a rhoRESUMEN
Apoptosis is a contributing cause of myocyte loss in ischemic heart disease. Recent work has shown that erythropoietin (EPO) offers protection against apoptosis in a wide variety of tissues. We demonstrate that the erythropoietin receptor (EPOR) is expressed in the neonatal rat ventricular myocyte (NRVM). Exposure of NRVMs to hypoxia, with recombinant human EPO, significantly decreased apoptosis as measured by TUNEL, flow cytometry, and caspase 3/7 like activity when compared to hypoxia treatment alone. EPO administered at the initiation of coronary artery occlusion in the rat significantly decreased apoptosis in the myocardial ischemic region. In the NRVM, EPO increased the activity of Akt. The anti-apoptotic effect of EPO was abrogated by co-treatment with LY294002, a specific blocker of phosphatidylinositol 3-kinase (PI3-K). Our study demonstrates that EPO inhibits apoptosis in the NRVM exposed to hypoxia, through an Akt-dependent pathway. EPO also inhibits apoptosis in the in vivo rat model of myocardial ischemia.
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Apoptosis , Eritropoyetina/fisiología , Hipoxia , Miocardio/citología , Miocardio/patología , Proteínas Serina-Treonina Quinasas , Proteínas Proto-Oncogénicas/metabolismo , Animales , Caspasa 3 , Caspasa 7 , Caspasas/metabolismo , Eritropoyetina/metabolismo , Citometría de Flujo , Ventrículos Cardíacos/citología , Inmunohistoquímica , Etiquetado Corte-Fin in Situ , Masculino , Isquemia Miocárdica , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt , Ratas , Ratas Sprague-Dawley , Receptores de Eritropoyetina/fisiologíaRESUMEN
Tuberculosis (TB) persists as a worldwide health crisis. Nearly one third of the world's population is infected with TB and it remains a critical public health issue. In the past two decades, international efforts have focused on improving identification of those infected with TB as well as supporting molecular microbiologists in developing better diagnostic techniques. Furthermore, implementation of programs such as directly observed therapy have assisted more patients in receiving and completing therapy. This review aims to identify some of the more relevant findings in the field of TB over the past few years with a special emphasis on TB in urban communities.
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SUMMARY: We tested three oxidant sensitive fluoroprobes (dihydrorhodamine [DHR], 2',7'-dichlorodihydrofluorescein [H(2)DCF], and dihydroethidium [DHE]) for interactions with three inhibitors of mitochondrial electron transport. DHR, H(2)DCF, and DHE produced large time-dependent increases in fluorescence in a cell-free medium that contained either of the site III inhibitors antimycin (A) and 2-heptyl-4-hydroxy-quinoline-N-oxide but minimal increases in medium that contained another site III inhibitor, myxothiazol (Mx). The interactions between A and each of the fluoroprobes occurred at concentrations of agent/probe that are frequently used in experiments designed to investigate cellular oxidant production. To define more effectively the nature of these agent/probe interactions, we determined the oxygen dependence of the interactions between A and each probe. The A/H(2)DCF and A/DHR interactions either were highly oxygen-dependent or exhibited a small degree of oxygen dependence, respectively, whereas the A/DHE interaction was oxygen-independent. Finally, we determined multiple ways to reduce the impact of the agent/probe interaction on data acquisition. The addition of either fetal bovine serum (10%) or albumin (5%) to the media abolished the A/DHR and A/H(2)DCF interactions. Shifting the excitation wavelength of DHE (from 470 to 530 nm) reduced measurement of the A/DHE interaction while preserving measurement of the intracellular signal. Collectively, these results emphasize the importance of testing for interactions between agents and probes, because these interactions can interfere with the accurate interpretation of experimental results. In addition, the methods presented for circumventing these interactions may be applicable to other experiments in which agent/probe interactions are an obstacle to accurate interpretation of the experimental results.