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1.
Cancer Causes Control ; 35(6): 973-979, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38421511

RESUMEN

PURPOSE: Previous studies have shown that individuals living in areas with persistent poverty (PP) experience worse cancer outcomes compared to those living in areas with transient or no persistent poverty (nPP). The association between PP and melanoma outcomes remains unexplored. We hypothesized that melanoma patients living in PP counties (defined as counties with ≥ 20% of residents living at or below the federal poverty level for the past two decennial censuses) would exhibit higher rates of incidence-based melanoma mortality (IMM). METHODS: We used Texas Cancer Registry data to identify the patients diagnosed with invasive melanoma or melanoma in situ (stages 0 through 4) between 2000 and 2018 (n = 82,458). Each patient's PP status was determined by their county of residence at the time of diagnosis. RESULTS: After adjusting for demographic variables, logistic regression analyses revealed that melanoma patients in PP counties had statistically significant higher IMM compared to those in nPP counties (17.4% versus 11.3%) with an adjusted odds ratio of 1.35 (95% CI 1.25-1.47). CONCLUSION: These findings highlight the relationship between persistent poverty and incidence-based melanoma mortality rates, revealing that melanoma patients residing in counties with persistent poverty have higher melanoma-specific mortality compared to those residing in counties with transient or no poverty. This study further emphasizes the importance of considering area-specific socioeconomic characteristics when implementing place-based interventions to facilitate early melanoma diagnosis and improve melanoma treatment outcomes.


Asunto(s)
Melanoma , Pobreza , Humanos , Melanoma/mortalidad , Melanoma/epidemiología , Texas/epidemiología , Femenino , Incidencia , Masculino , Pobreza/estadística & datos numéricos , Persona de Mediana Edad , Adulto , Anciano , Sistema de Registros , Adulto Joven , Neoplasias Cutáneas/mortalidad , Neoplasias Cutáneas/epidemiología
2.
Cancer Causes Control ; 34(5): 407-420, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-37027053

RESUMEN

PURPOSE: The social vulnerability index (SVI), developed by the Centers for Disease Control and Prevention, is a novel composite measure encompassing multiple variables that correspond to key social determinants of health. The objective of this review was to investigate innovative applications of the SVI to oncology research and to employ the framework of the cancer care continuum to elucidate further research opportunities. METHODS: A systematic search for relevant articles was performed in five databases from inception to 13 May 2022. Included studies applied the SVI to analyze outcomes in cancer patients. Study characteristics, patent populations, data sources, and outcomes were extracted from each article. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. RESULTS: In total, 31 studies were included. Along the cancer care continuum, five applied the SVI to examine geographic disparities in potentially cancer-causing exposures; seven in cancer diagnosis; fourteen in cancer treatment; nine in treatment recovery; one in survivorship care; and two in end-of-life care. Fifteen examined disparities in mortality. CONCLUSION: In highlighting place-based disparities in patient outcomes, the SVI represents a promising tool for future oncology research. As a reliable geocoded dataset, the SVI may inform the development and implementation of targeted interventions to prevent cancer morbidity and mortality at the neighborhood level.


Asunto(s)
Neoplasias , Vulnerabilidad Social , Estados Unidos , Humanos , Neoplasias/terapia , Centers for Disease Control and Prevention, U.S. , Continuidad de la Atención al Paciente , Medición de Riesgo
3.
Clin Exp Dermatol ; 48(8): 903-908, 2023 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-37191210

RESUMEN

BACKGROUND: Merkel cell carcinoma (MCC) is a highly aggressive neuroendocrine cutaneous carcinoma aetiologically linked to the Merkel cell polyomavirus (MCPyV). Immune checkpoint inhibitors are currently the first-line therapy for metastatic MCC; however, the treatment is effective in only about half of patients, highlighting the need for alternative therapies. Selinexor (KPT-330) is a selective inhibitor of nuclear exportin 1 (XPO1) and has been shown to inhibit MCC cell growth in vitro, but the pathogenesis has not been established. Decades of research have established that cancer cells significantly upregulate lipogenesis to meet an increased demand for fatty acids and cholesterol. Treatments that inhibit lipogenic pathways may halt cancer cell proliferation. AIM: To determine the effect of increasing doses of selinexor on fatty acid and cholesterol synthesis in MCPyV-positive MCC (MCCP) cell lines and aid in elucidating the mechanism by which selinexor prevents and reduces MCC growth. METHODS: MKL-1 and MS-1 cell lines were treated with increasing doses of selinexor for 72 h. Protein expression quantification was determined using chemiluminescent Western immunoblotting and densitometric analysis. Fatty acids and cholesterol were quantified using free fatty acid assay and cholesterol ester detection kits. RESULTS: Selinexor causes statistically significant reductions of the lipogenic transcription factors sterol regulatory element-binding proteins 1 and 2, and lipogenic enzymes acetyl-CoA carboxylase, fatty acid synthase, squalene synthase and 3ß-hydroxysterol Δ-24-reductase in a dose-dependent manner in two MCCP cell lines. Although inhibiting the fatty acid synthesis pathway results in meaningful decreases in fatty acids, the cellular cholesterol levels did not demonstrate such reductions. CONCLUSION: For patients with metastatic MCC refractory to immune checkpoint inhibitors, selinexor may provide clinical benefit through the inhibition of the lipogenesis pathway; however, further research and clinical trials are needed to evaluate these findings.


Asunto(s)
Carcinoma de Células de Merkel , Neoplasias Cutáneas , Humanos , Carcinoma de Células de Merkel/patología , Inhibidores de Puntos de Control Inmunológico , Lipogénesis , Línea Celular , Neoplasias Cutáneas/patología , Ácidos Grasos
4.
Dermatol Surg ; 49(4): 343-347, 2023 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-36799879

RESUMEN

BACKGROUND: Repair options for Mohs surgical defects include primary closure, flap or graft, or healing by second intention. These options may not be optimal in all cases. A dehydrated complete human placental membrane (dCHPM) allograft may serve as an alternative repair option. OBJECTIVE: To assess the aesthetic and functional outcomes of an alternative repair technique for Mohs surgical defects of the nose. METHODS: Twenty patients with Mohs surgical defects of the nose repaired with a dCHPM allograft were retrospectively identified. Photographs were used to demonstrate surgical technique and outcomes. Two blinded observers evaluated final outcomes using the Patient and Observer Scar Assessment Scale. RESULTS: Observers rated the scar outcome a combined mean score of 8.4 ± 3.2 (scale 5-50). Patients rated their outcomes a mean of 12.6 ± 7.4 (scale 6-60). The mean "Overall Opinion score" was 2.5 ± 1.8 by patients and 1.9 ± 1.3 by observers (scale 1-10). LIMITATIONS: This was a single institution study with a small sample size. CONCLUSION: Our study demonstrates that dCHPM allografts are a viable alternative repair option for Mohs surgical defects of the nose.


Asunto(s)
Cicatriz , Neoplasias Nasales , Embarazo , Humanos , Femenino , Cicatriz/cirugía , Estudios Retrospectivos , Cirugía de Mohs , Placenta/cirugía , Nariz/cirugía , Nariz/patología , Neoplasias Nasales/cirugía , Aloinjertos
5.
J Cancer Educ ; 38(1): 364-369, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-35013902

RESUMEN

Educational interventions to support Primary Care Provider (PCP) performance of skin cancer examinations typically train PCPs to "triage and refer," an approach that may result in diagnostic delays in regions without appropriate access to dermatology care. To address the needs of PCPs and patients in regions without appropriate access to dermatology care, we developed a multi-faceted pilot intervention, including a curriculum and telementoring, designed to support PCP performance of skin cancer detection examinations. Our intervention offers two levels of proficiency: "triage and refer" and "diagnose and manage." The pilot intervention was conducted in collaboration with the Texas Tech University of Health Sciences Center El Paso, TX Family and Community Medicine Department (TTUHSC-El Paso). Participation in the intervention was voluntary, and 18-22 family medicine resident physicians completed the intervention tests. The participating family medicine resident physicians demonstrated statistically significant gains in knowledge and self-efficacy at the immediate post-intervention time points. Further adaption of the pilot intervention is needed to meet the needs of practicing PCPs. The pilot tests require further adaption and validation. Translating education delivery from live/synchronous to interactive virtual/asynchronous modules will support greater educational dissemination, and telementoring support is essential to address challenging cases encountered during patient care.


Asunto(s)
Neoplasias Cutáneas , Humanos , Neoplasias Cutáneas/diagnóstico , Neoplasias Cutáneas/prevención & control , Texas , Educación Médica Continua , Curriculum , Atención Primaria de Salud
6.
Clin Exp Dermatol ; 47(7): 1354-1357, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35120268

RESUMEN

Merkel cell carcinoma (MCC) is a highly lethal cutaneous carcinoma, which in ~80% of cases in the USA is aetiologically linked to Merkel cell polyomavirus (MCPyV). Immune checkpoint inhibitors (ICIs) can successfully treat ~50% of patients with metastatic MCC, but some MCCs are refractory to ICIs, possibly due to altered DNA damage response (DDR). Selinexor, an anticancer therapy that is currently approved in combination with chemotherapy for multiple myeloma, downregulates the small T and large T tumour antigens in MCC through selective inhibition of nuclear exportin 1 (XPO1). We examined the effect of varying doses of selinexor on DDR protein expression in MCPyV-positive and MCPyV-negative MCC cells. Selinexor was found to inhibit DDR protein expression in both MCPyV-positive and MCPyV-negative cells. Addition of selinexor alone or combined with ICI may be a promising treatment for MCC, but further in vivo research and clinical trials are required to validate these findings.


Asunto(s)
Carcinoma de Células de Merkel , Poliomavirus de Células de Merkel , Neoplasias Cutáneas , Carcinoma de Células de Merkel/tratamiento farmacológico , Carcinoma de Células de Merkel/patología , Daño del ADN , Humanos , Hidrazinas , Poliomavirus de Células de Merkel/genética , Neoplasias Cutáneas/genética , Triazoles
7.
J Drugs Dermatol ; 21(7): 797-798, 2022 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-35816058

RESUMEN

A lack of clinical trials devoted specifically to treatment protocols in minority groups and diverse individuals with skin of color (SOC) exists. Treatment decisions often vary based on patient cultural preferences and have differing efficacies based on skin type. As such, it is important to evaluate the diversity of participants being included in dermatology clinical trials.


Asunto(s)
Acné Vulgar , Acné Vulgar/diagnóstico , Acné Vulgar/tratamiento farmacológico , Ensayos Clínicos como Asunto , Humanos , Piel , Pigmentación de la Piel
8.
J Card Surg ; 37(5): 1233-1239, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35187728

RESUMEN

OBJECTIVE: The study aimed to evaluate the indications and describe the aortic valve reconstruction techniques by Ozaki's procedure in Vietnam and report mid-term outcomes of this technique in Vietnam. METHODS: Between June 2017 and December 2019, 72 patients diagnosed with isolated aortic valve disease, with a mean age of 52.9 (19-79 years old), and a male:female ratio of 3:1 underwent aortic valve reconstruction surgery by Ozaki's technique at Cardiovascular Center, E Hospital, Vietnam. RESULTS: The aortic valve diseases consisted of aortic stenosis (42%), aortic regurgitation (28%), and a combination of both (30%). In addition, the proportion of aortic valves with bicuspid morphology and small annulus (≤21 mm) was 28% and 38.9%, respectively. The mean aortic cross-clamp time was 106 ± 13.8 min, mean cardiopulmonary bypass time was 136.7 ± 18.5 min, and 2.8% of all patients required conversion to prosthetic valve replacement surgery. The mean follow-up time was 26.4 months (12-42 months), the survival rate was 95.8%, the reoperation rate was 2.8%, and rate of postoperative moderate or higher aortic valve regurgitation was 4.2%. Postoperative valvular hemodynamics was favorable, with a peak pressure gradient of 16.1 mmHg and an effective orifice area index of 2.3 cm2 . CONCLUSIONS: This procedure was safe and effective, with favorable valvular hemodynamics and a low rate of valvular degeneration. However, more long-term follow-up data are needed.


Asunto(s)
Insuficiencia de la Válvula Aórtica , Estenosis de la Válvula Aórtica , Implantación de Prótesis de Válvulas Cardíacas , Adulto , Anciano , Válvula Aórtica/cirugía , Insuficiencia de la Válvula Aórtica/cirugía , Estenosis de la Válvula Aórtica/cirugía , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Pericardio/trasplante , Resultado del Tratamiento , Vietnam/epidemiología , Adulto Joven
9.
J Nematol ; 51: 1-10, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31088027

RESUMEN

The interaction between Fusarium oxysporum f. sp. vasinfectum (Fov) and Meloidogyne incognita (root-knot nematode) resulting in Fusarium wilt (FW) of cotton is well-known. Although Belonolaimus longicaudatus (sting nematode) can also interact with Fov and cause FW, it has long been believed that virtually all of the FW in Georgia is caused by the interaction of Fov with M. incognita. In recent years, FW has been reported more frequently in Georgia, which suggests that something affecting the disease complex may have changed. In 2015 and 2016, a survey of 27 Georgia cotton fields in 10 counties was conducted. At least 10 soil and stem samples per field were collected from individual plants showing symptoms of FW to quantify plant-parasitic nematode levels and identify Fov races. Fov race 1 was identified in all samples in 2015, but one sample also had the LA110 genotype and another sample also had the LA108 genotype. In 2016, all Fov races and genotypes found in 2015 were present, however, MDS-12 and LA127/140 also were found. Meloidogyne incognita was present in 18% of fields in 2015 and 40% in 2016, whereas B. longicaudatus was present in all fields in 2015 and 75% of fields in 2016. Regardless of whether they occurred separately or together, M. incognita and B. longicaudatus were present, respectively, in 18% and 55% of individual samples in 2015 and 40% and 51% in 2016. However, M. incognita without B. longicaudatus was found in 7% of samples in 2015 and 34% in 2016, whereas B. longicaudatus without M. incognita was found in 45% of samples in 2015 and 44% in 2016. We conclude that Fov race 1 continues to be the dominant race in Georgia and many instances of FW in Georgia may be due to Fov interacting with B. longicaudatus and not M. incognita as previously believed.The interaction between Fusarium oxysporum f. sp. vasinfectum (Fov) and Meloidogyne incognita (root-knot nematode) resulting in Fusarium wilt (FW) of cotton is well-known. Although Belonolaimus longicaudatus (sting nematode) can also interact with Fov and cause FW, it has long been believed that virtually all of the FW in Georgia is caused by the interaction of Fov with M. incognita. In recent years, FW has been reported more frequently in Georgia, which suggests that something affecting the disease complex may have changed. In 2015 and 2016, a survey of 27 Georgia cotton fields in 10 counties was conducted. At least 10 soil and stem samples per field were collected from individual plants showing symptoms of FW to quantify plant-parasitic nematode levels and identify Fov races. Fov race 1 was identified in all samples in 2015, but one sample also had the LA110 genotype and another sample also had the LA108 genotype. In 2016, all Fov races and genotypes found in 2015 were present, however, MDS­12 and LA127/140 also were found. Meloidogyne incognita was present in 18% of fields in 2015 and 40% in 2016, whereas B. longicaudatus was present in all fields in 2015 and 75% of fields in 2016. Regardless of whether they occurred separately or together, M. incognita and B. longicaudatus were present, respectively, in 18% and 55% of individual samples in 2015 and 40% and 51% in 2016. However, M. incognita without B. longicaudatus was found in 7% of samples in 2015 and 34% in 2016, whereas B. longicaudatus without M. incognita was found in 45% of samples in 2015 and 44% in 2016. We conclude that Fov race 1 continues to be the dominant race in Georgia and many instances of FW in Georgia may be due to Fov interacting with B. longicaudatus and not M. incognita as previously believed.

10.
Analyst ; 143(12): 2819-2827, 2018 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-29774908

RESUMEN

Fluorescence signal enhancement induced by the binding of intercalators to DNA has been broadly utilized in various DNA detection methods. In most instances the increase in fluorescence intensity is associated with a concomitant increase of fluorescence lifetime. This increase of the fluorescence lifetime presents an additional opportunity to increase detection sensitivity. In this paper, we present a new approach to significantly enhance the sensitivity in detecting minute DNA concentrations. The approach is based on simultaneous use of time-gated detection and multi-pulse pumping. By using a calibrated burst of short pulses we greatly enhance the contribution of long-lived fluorescence species, thus enabling easy time-gated detection. Using a classic DNA intercalator - Ethidium Bromide (EtBr) - as an example with our novel multi-pulse pumping and time-gated detection technique, we were able to increase detection sensitivity over 70-fold with only 3 pulse excitation. This approach is generic and can be used with any analytical probe (exhibiting about 10 times change in lifetime) that shows an increase in fluorescence signal and fluorescence lifetime upon binding to a target.


Asunto(s)
ADN/análisis , Sustancias Intercalantes/química , Espectrometría de Fluorescencia , Etidio
11.
Nanotechnology ; 28(6): 065705, 2017 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-28050974

RESUMEN

Graphene possesses a number of advantageous properties, however, does not exhibit optical emission, which limits its use in optoelectronics. Unlike graphene, its functional derivative, graphene oxide (GO) exhibits fluorescence emission throughout the visible. Here, we focus on controlled methods for tuning the optical properties of GO. We introduce ozone treatment of reduced graphene oxide (RGO) in order to controllably transform it from non-emissive graphene-like material into GO with a specific fluorescence emission response. Solution-based treatment of RGO for 5-45 min with ∼1.2 g l-1 ozone/oxygen gas mixture yields a drastic color change, bleaching of the absorption in the visible and the stepwise increase in fluorescence intensity and lifetime. This is attributed to the introduction of oxygen-containing functional groups to RGO graphitic platform as detected by the infrared spectroscopy. A reverse process: controllable quenching of this fluorescence is achieved by the thermal treatment of GO in aqueous suspension up to 90 °C. This methodology allows for the wide range alteration of GO optical properties starting from the dark-colored non-emissive RGO material up to nearly transparent highly ozone-oxidized GO showing substantial fluorescence emission. The size of the GO flakes is concomitantly altered by oxidation-induced scission. Semi-empirical PM3 theoretical calculations on HyperChem models are utilized to explore the origins of optical response from GO. Two models are considered, attributing the induced emission either to the localized states produced by oxygen-containing addends or the islands of graphitic carbon enclosed by such addends. Band gap values calculated from the models are in the agreement with experimentally observed transition peak maxima. The controllable variation of GO optical properties in aqueous suspension by ozone and thermal treatments shown in this work provides a route to tune its optical response for particular optoelectronics or biomedical applications.

12.
Phys Chem Chem Phys ; 19(44): 29934-29939, 2017 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-29090298

RESUMEN

Styryl dyes, specifically LDS group dyes, are known solvatochromic and electrochromic probes for monitoring mitochondrial potential in cellular environments. However, the ability of these dyes to respond to fluctuations in viscosity, pH and temperature has not been established. In this study, we demonstrated that LDS 798 (also known as Styryl-11) can sense environmental viscosity (via fluorescence lifetime changes) as well as pH changes (ratiometric intensity change) in the absence of polarity variations. Polarity changes can be probed by spectral changes using LDS 798. Therefore, all properties of the media should be considered, when these types of dyes are used as electrochromic/solvatochromic sensors in cellular environments.

13.
Sensors (Basel) ; 17(12)2017 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-29215582

RESUMEN

This paper describes recent process modifications made to enhance the performance of interline and electron-multiplying charge-coupled-device (EMCCD) image sensors. By use of MeV ion implantation, quantum efficiency in the NIR region of the spectrum was increased by 2×, and image smear was reduced by 6 dB. By reducing the depth of the shallow photodiode (PD) implants, the photodiode-to-vertical-charge-coupled-device (VCCD) transfer gate voltage required for no-lag operation was reduced by 3 V, and the electronic shutter voltage was reduced by 9 V. The thinner, surface pinning layer also resulted in a reduction of smear by 4 dB in the blue portion of the visible spectrum. For EMCCDs, gain aging was eliminated by providing an oxide-only dielectric under its multiplication phase, while retaining the oxide-nitride-oxide (ONO) gate dielectrics elsewhere in the device.

14.
Anal Bioanal Chem ; 408(24): 6649-58, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27457106

RESUMEN

The natural porosity of eggshells allows hen eggs to become contaminated with microbes from the nesting material and environment. Those microorganisms can later proliferate due to the humid ambient conditions while stored in refrigerators, causing a potential health hazard to the consumer. The microbes' volatile organic compounds (mVOCs) are released by both fungi and bacteria. We studied mVOCs produced by aging eggs likely contaminated by fungi and fresh eggs using the non-invasive detection method of gas-phase sampling of volatiles followed by gas chromatography/mass spectrometry (GC/MS) analysis. Two different fungal species (Cladosporium macrocarpum and Botrytis cinerea) and two different bacteria species (Stenotrophomas rhizophila and Pseudomonas argentinensis) were identified inside the studied eggs. Two compounds believed to originate from the fungi themselves were identified. One fungus-specific compound was found in both egg and the fungi: trichloromethane. Graphical abstract Trichloromethane is a potential biomarker of fungal contamination of eggs.


Asunto(s)
Bacterias/aislamiento & purificación , Pollos/microbiología , Cáscara de Huevo/microbiología , Contaminación de Alimentos/análisis , Hongos/aislamiento & purificación , Compuestos Orgánicos Volátiles/análisis , Animales , Diseño de Equipo , Cromatografía de Gases y Espectrometría de Masas/instrumentación , Cromatografía de Gases y Espectrometría de Masas/métodos , Microextracción en Fase Sólida/instrumentación , Microextracción en Fase Sólida/métodos
15.
Intervirology ; 58(6): 382-5, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-27055259

RESUMEN

Merkel cell polyomavirus (MCPyV), trichodysplasia spinulosa-associated polyomavirus (TSPyV), human polyomavirus 6 (HPyV6), and human polyomavirus 7 (HPyV7) are implicated in the pathogeneses of distinct hyperproliferative cutaneous growths and encode small tumor (sT) antigens. The current study demonstrates that the four sT antigens differentially regulate 4E-binding protein 1 (4E-BP1) serine 65 hyperphosphorylation. MCPyV and HPyV7 sT antigens were found to promote the presence of the hyperphosphorylated 4E-BP1-δ isoform, while TSPyV and HPyV6 sT antigens had no significant effects. Given that hyperphosphorylated 4E-BP1 is associated with an aggressive cancer phenotype, our findings confirm the previously reported pathogenicity of MCPyV sT and highlight a novel mechanism by which HPyV7 sT may mediate oncogenesis.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/genética , Antígenos Transformadores de Poliomavirus/inmunología , Poliomavirus de Células de Merkel/inmunología , Fosfoproteínas/genética , Polyomaviridae/inmunología , Infecciones por Polyomavirus/inmunología , Poliomavirus/inmunología , Proteínas de Ciclo Celular , Humanos , Infecciones por Polyomavirus/virología , Neoplasias Cutáneas/virología
17.
Methods ; 66(2): 292-8, 2014 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-23994243

RESUMEN

Applications of fluorescence based imaging techniques for detection in cellular and tissue environments are severely limited by autofluorescence of endogenous components of cells, tissue, and the fixatives used in sample processing. To achieve sufficient signal-to-background ratio, a high concentration of the probe needs to be used which is not always feasible. Since typically autofluorescence is in the nanosecond range, long-lived fluorescence probes in combination with time-gated detection can be used for suppression of unwanted autofluorescence. Unfortunately, this requires the sacrifice of the large portion the probe signal in order to sufficiently filter the background. We report a simple and practical approach to achieve a many-fold increase in the intensity of a long-lived probe without increasing the background fluorescence. Using controllable, well separated bursts of closely spaced laser excitation pulses, we are able to highly increase the fluorescence signal of a long-lived marker over the endogenous fluorescent background and scattering, thereby greatly increasing detection sensitivity. Using a commercially available confocal microscopy system equipped with a laser diode and time correlated single photon counting (TCSPC) detection, we are able to enhance the signal of a long-lived Ruthenium (Ru)-based probe by nearly an order of magnitude. We used 80 MHz bursts of pulses (12.5 ns pulse separation) repeated with a 320 kHz repetition rate as needed to adequately image a dye with a 380 ns lifetime. Just using 10 pulses in the burst increases the Ru signal almost 10-fold without any increase in the background signal.


Asunto(s)
Imagen Óptica/métodos , Animales , Colorantes Fluorescentes/química , Colorantes Fluorescentes/metabolismo , Microscopía Confocal , Microscopía Fluorescente , Ratas , Células Ganglionares de la Retina/metabolismo , Relación Señal-Ruido , Tubulina (Proteína)/metabolismo
18.
Phytopathology ; 105(8): 1036-42, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25894316

RESUMEN

The study of microorganisms that reside on plant leaf surfaces, or phyllosphere microbiology, greatly benefits from the availability of artificial surfaces that mimic in one or more ways the complexity of foliage as a microbial habitat. These leaf surface proxies range from very simple, such as nutrient agars that can reveal the metabolic versatility or antagonistic properties of leaf-associated microorganisms, to the very complex, such as silicon-based casts that replicate leaf surface topography down to nanometer resolution. In this review, we summarize the various uses of artificial surfaces in experimental phyllosphere microbiology and discuss how these have advanced our understanding of the biology of leaf-associated microorganisms and the habitat they live in. We also provide an outlook into future uses of artificial leaf surfaces, foretelling a greater role for microfluidics to introduce biological and chemical gradients into artificial leaf environments, stressing the importance of artificial surfaces to generate quantitative data that support computational models of microbial life on real leaves, and rethinking the leaf surface ('phyllosphere') as a habitat that features two intimately connected but very different compartments, i.e., the leaf surface landscape ('phylloplane') and the leaf surface waterscape ('phyllotelma').


Asunto(s)
Plantas/microbiología , Simulación por Computador , Ecosistema , Epidermis de la Planta/microbiología , Hojas de la Planta/microbiología
19.
Phys Chem Chem Phys ; 16(48): 27037-42, 2014 Dec 28.
Artículo en Inglés | MEDLINE | ID: mdl-25381865

RESUMEN

Fluorescence properties of a novel homodimeric BODIPY dye rotor for Fluorescence Lifetime Imaging Microscopy (FLIM) are reported. Steady state and time resolved fluorescence measurements established the viscosity dependent behaviour in vitro. Homodimeric BODIPY embedded in different membrane mimicking lipid vesicles (DPPC, POPC and POPC plus cholesterol) is demonstrated to be a viable sensor for fluorescence lifetime based viscosity measurements. Moreover, SKOV3 cells readily endocytosed the dye, which accumulated in membranous structures inside the cytoplasm thereby allowing viscosity mapping of internal cell components.


Asunto(s)
Compuestos de Boro/química , Membrana Celular/química , Citoplasma/química , Colorantes Fluorescentes/química , Línea Celular , Dimerización , Humanos , Microscopía Fluorescente , Imagen Óptica , Viscosidad
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