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1.
Clin Colon Rectal Surg ; 37(3): 146-156, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38606044

RESUMO

The coming of age for cancer treatment has experienced exponential growth in the last decade with the addition of immunotherapy as the fourth pillar to the fundamentals of cancer treatment-chemotherapy, surgery, and radiation-taking oncology to an astounding new frontier. In this time, rapid developments in computational biology coupled with immunology have led to the exploration of priming the host immune system through vaccination to prevent and treat certain subsets of cancer such as melanoma and hereditary colorectal cancer. By targeting the immune system through tumor-specific antigens-namely, neoantigens (neoAgs)-the future of cancer prevention may lie within arm's reach by employing neoAg vaccines as an immune-preventive modality for hereditary cancer syndromes like Lynch syndrome. In this review, we discuss the history, current trends, utilization, and future direction of neoAg-based vaccines in the setting of hereditary colorectal cancer.

2.
Gastroenterology ; 166(5): 787-801.e11, 2024 05.
Artigo em Inglês | MEDLINE | ID: mdl-38244726

RESUMO

BACKGROUND & AIMS: Lynch syndrome (LS) carriers develop mismatch repair-deficient neoplasia with high neoantigen (neoAg) rates. No detailed information on targetable neoAgs from LS precancers exists, which is crucial for vaccine development and immune-interception strategies. We report a focused somatic mutation and frameshift-neoAg landscape of microsatellite loci from colorectal polyps without malignant potential (PWOMP), precancers, and early-stage cancers in LS carriers. METHODS: We generated paired whole-exome and transcriptomic sequencing data from 8 colorectal PWOMP, 41 precancers, 8 advanced precancers, and 12 early-stage cancers of 43 LS carriers. A computational pipeline was developed to predict, rank, and prioritize the top 100 detected mutated neoAgs that were validated in vitro using ELISpot and tetramer assays. RESULTS: Mutation calling revealed >10 mut/Mb in 83% of cancers, 63% of advanced precancers, and 20% of precancers. Cancers displayed an average of 616 MHC-I neoAgs/sample, 294 in advanced precancers, and 107 in precancers. No neoAgs were detected in PWOMP. A total of 65% of our top 100 predicted neoAgs were immunogenic in vitro, and were present in 92% of cancers, 50% of advanced precancers, and 29% of precancers. We observed increased levels of naïve CD8+ and memory CD4+ T cells in mismatch repair-deficient cancers and precancers via transcriptomics analysis. CONCLUSIONS: Shared frameshift-neoAgs are generated within unstable microsatellite loci at initial stages of LS carcinogenesis and can induce T-cell responses, generating opportunities for vaccine development, targeting LS precancers and early-stage cancers.


Assuntos
Antígenos de Neoplasias , Neoplasias Colorretais Hereditárias sem Polipose , Sequenciamento do Exoma , Mutação da Fase de Leitura , Humanos , Neoplasias Colorretais Hereditárias sem Polipose/genética , Neoplasias Colorretais Hereditárias sem Polipose/imunologia , Antígenos de Neoplasias/imunologia , Antígenos de Neoplasias/genética , Feminino , Mutação , Masculino , Pessoa de Meia-Idade , Reparo de Erro de Pareamento de DNA/genética , Repetições de Microssatélites , Instabilidade de Microssatélites , Neoplasias Colorretais/genética , Neoplasias Colorretais/imunologia , Neoplasias Colorretais/prevenção & controle , Adulto , Vacinas Anticâncer/imunologia , Vacinas Anticâncer/uso terapêutico
3.
Front Oncol ; 13: 1146825, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37168379

RESUMO

Objective: Lynch Syndrome (LS) carriers have a significantly increased risk of developing colorectal cancer (CRC) during their lifetimes. Further stratification of this patient population may help in identifying additional risk factors that predispose to colorectal carcinogenesis. In most LS patients CRC may arise from adenomas, although an alternative non-polypoid carcinogenesis pathway has been proposed for PMS2 carriers. Using data from our institutional LS cohort, our aim was to describe our current colorectal screening outcomes with a focus on the incidence of adenomas in the context of different MMR genotypes and patient demographics such as gender, race, and ethnicity. Design: We collected demographics, genetic, colonoscopy, and pathology results from a total of 163 LS carriers who obtained regular screening care at MD Anderson Cancer Center. Data were extracted from the electronic health records into a REDCap database for analysis. Logistic regressions were performed to measure the association between MMR variants and the likelihood of adenomas, advanced adenomas, and CRC. Then, we analyzed the cumulative incidences of these outcomes for the first 36 months following enrollment using Kaplan-Meier incidence curves, and Cox proportional hazard regressions. Results: On multivariate analysis, age (≥45 years old) was associated with an increased risk of developing adenomas (P=0.034). Patients with a prior or active cancer status were less likely to develop adenomas (P=0.015), despite of the lack of association between surgical history with this outcome (P=0.868). We found no statistically significant difference in likelihood of adenoma development between MLH1 and MSH2/EPCAM, MSH6, and PMS2 carriers. Moreover, we observed no statistically significant difference in the likelihood of advanced adenomas or CRC for any measured covariates. On Cox proportional hazard, compared to MLH1 carriers, the incidence of adenomas was highest among MSH2/EPCAM carriers during for the first 36-months of follow-up (P<0.001). We observed a non-statistically significant trend for Hispanics having a higher and earlier cumulative incidence of adenomas compared to non-Hispanics (P=0.073). No MMR carrier was more likely to develop advanced adenomas. No difference in the incidence of CRC by MMR gene (P=0.198). Conclusion: Screening recommendations for CRC in LS patients should be based on specific MMR variants and should also be tailored to consider patient demographics.

4.
Front Immunol ; 14: 1162669, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37207208

RESUMO

Background: Recent clinical trial data from Lynch Syndrome (LS) carriers demonstrated that naproxen administered for 6-months is a safe primary chemoprevention that promotes activation of different resident immune cell types without increasing lymphoid cellularity. While intriguing, the precise immune cell types enriched by naproxen remained unanswered. Here, we have utilized cutting-edge technology to elucidate the immune cell types activated by naproxen in mucosal tissue of LS patients. Methods: Normal colorectal mucosa samples (pre- and post-treatment) from a subset of patients enrolled in the randomized and placebo-controlled 'Naproxen Study' were obtained and subjected to a tissue microarray for image mass cytometry (IMC) analysis. IMC data was processed using tissue segmentation and functional markers to ascertain cell type abundance. Computational outputs were then used to quantitatively compare immune cell abundance in pre- and post-naproxen specimens. Results: Using data-driven exploration, unsupervised clustering identified four populations of immune cell types with statistically significant changes between treatment and control groups. These four populations collectively describe a unique cell population of proliferating lymphocytes within mucosal samples from LS patients exposed to naproxen. Conclusions: Our findings show that daily exposure of naproxen promotes T-cell proliferation in the colonic mucosa, which paves way for developing combination of immunoprevention strategies including naproxen for LS patients.


Assuntos
Antineoplásicos , Vacinas Anticâncer , Neoplasias Colorretais Hereditárias sem Polipose , Humanos , Naproxeno/farmacologia , Imunoterapia , Linfócitos , Mucosa Intestinal , Quimioprevenção
5.
Biomedicines ; 10(11)2022 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-36428527

RESUMO

Amniotic fluid (AF) provides critical biological and physical support for the developing fetus. While AF is an excellent source of progenitor cells with regenerative properties, recent investigations indicate that cell-free AF (cfAF), which consists of its soluble components and extracellular vesicles, can also stimulate regenerative and reparative activities. This review summarizes published fundamental, translational, and clinical investigations into the biological activity and potential use of cfAF as a therapeutic agent. Recurring themes emerge from these studies, which indicate that cfAF can confer immunomodulatory, anti-inflammatory, and pro-growth characteristics to the target cells/tissue with which they come into contact. Another common observation is that cfAF seems to promote a return of cells/tissue to a homeostatic resting state when applied to a model of cell stress or disease. The precise mechanisms through which these effects are mediated have not been entirely defined, but it is clear that cfAF can safely and effectively treat cutaneous wounds and perhaps orthopedic degenerative conditions. Additional applications are currently being investigated, but require further study to dissect the fundamental mechanisms through which its regenerative effects are mediated. By doing so, rational design can be used to fully unlock its potential in the biotechnology lab and in the clinic.

6.
Biomedicines ; 10(9)2022 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-36140291

RESUMO

Myofibroblast activation is a cellular response elicited by a variety of physiological or pathological insults whereby cells initiate a coordinated response intended to eradicate the insult and then revert back to a basal state. However, an underlying theme in various disease states is persistent myofibroblast activation that fails to resolve. Based on multiple observations, we hypothesized that the secreted factors harvested from co-culturing amniotic stem cells might mimic the anti-inflammatory state that cell-free amniotic fluid (AF) elicits. We optimized an amnion epithelial and amniotic fluid cell co-culture system, and tested this hypothesis in the context of myofibroblast activation. However, we discovered that co-cultured amniotic cell conditioned media (coACCM) and AF have opposing effects on myofibroblast activation: coACCM activates the epithelial-mesenchymal transition (EMT) and stimulates gene expression patterns associated with myofibroblast activation, while AF does the opposite. Intriguingly, extracellular vesicles (EVs) purified from AF are necessary and sufficient to activate EMT and inflammatory gene expression patterns, while the EV-depleted AF potently represses these responses. In summary, these data indicate that coACCM stimulates myofibroblast activation, while AF represses it. We interpret these findings to suggest that coACCM, AF, and fractionated AF represent unique biologics that elicit different cellular responses that are correlated with a wide variety of pathological states, and therefore could have broad utility in the clinic and the lab.

8.
Mil Med ; 2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34755846

RESUMO

First-time use of Ranger O Low Titer (ROLO) blood and implementation of a forward-walking blood bank using predetermined donors proved essential in the survival of a 33-year-old active duty soldier following a complex blast injury during combat operations. The patient sustained significant bone, soft tissue, and vascular damage and continued to deteriorate despite resuscitation with cold-stored whole blood (WB). Only after utilizing the ROLO battle drill and transfusing with fresh WB was the patient able to be stabilized and evacuated. In this case report, we discuss how ROLO walking blood bank takes the next step in aiding resuscitation, providing smaller, forward-deployed units with blood resupply without the administrative burden of storage, particularly in resource-scarce environments. We provide an overview of WB and contrast its use to that of component therapy. In conjunction with the Golden Hour, ROLO can be incorporated as the standard damage control resuscitation to reduce the risks of noncompressible hemorrhage. By taking precautionary steps in the pre-deployment setting, ROLO offers an invaluable alternative to conventional resuscitation.

9.
Cancer Prev Res (Phila) ; 14(9): 851-862, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34266857

RESUMO

Familial adenomatous polyposis (FAP) is a hereditary colorectal cancer syndrome, which results in the development of hundreds of adenomatous polyps carpeting the gastrointestinal tract. NSAIDs have reduced polyp burden in patients with FAP and synthetic rexinoids have demonstrated the ability to modulate cytokine-mediated inflammation and WNT signaling. This study examined the use of the combination of an NSAID (sulindac) and a rexinoid (bexarotene) as a durable approach for reducing FAP colonic polyposis to prevent colorectal cancer development. Whole transcriptomic analysis of colorectal polyps and matched normal mucosa in a cohort of patients with FAP to identify potential targets for prevention in FAP was performed. Drug-dose synergism of sulindac and bexarotene in cell lines and patient-derived organoids was assessed, and the drug combination was tested in two different mouse models. This work explored mRNA as a potential predictive serum biomarker for this combination in FAP. Overall, transcriptomic analysis revealed significant activation of inflammatory and cell proliferation pathways. A synergistic effect of sulindac (300 µmol/L) and bexarotene (40 µmol/L) was observed in FAP colonic organoids with primary targeting of polyp tissue compared with normal mucosa. This combination translated into a significant reduction in polyp development in ApcMin/+ and ApcLoxP/+-Cdx2 mice. Finally, the reported data suggest miRNA-21 could serve as a predictive serum biomarker for polyposis burden in patients with FAP. These findings support the clinical development of the combination of sulindac and bexarotene as a treatment modality for patients with FAP. PREVENTION RELEVANCE: This study identified a novel chemopreventive regimen combining sulindac and bexarotene to reduce polyposis in patients with FAP using in silico tools, ex vivo, and in vivo models. This investigation provides the essential groundwork for moving this drug combination forward into a clinical trial.


Assuntos
Polipose Adenomatosa do Colo/tratamento farmacológico , Bexaroteno/administração & dosagem , Neoplasias Intestinais/prevenção & controle , Sulindaco/administração & dosagem , Polipose Adenomatosa do Colo/genética , Polipose Adenomatosa do Colo/patologia , Pólipos Adenomatosos/tratamento farmacológico , Pólipos Adenomatosos/genética , Pólipos Adenomatosos/patologia , Adulto , Animais , Anti-Inflamatórios não Esteroides/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinogênese/efeitos dos fármacos , Carcinogênese/genética , Carcinogênese/patologia , Estudos de Casos e Controles , Células Cultivadas , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Células HCT116 , Células HT29 , Humanos , Neoplasias Intestinais/genética , Neoplasias Intestinais/patologia , Masculino , Camundongos , Camundongos Transgênicos
10.
Cancer Res ; 81(10): 2760-2773, 2021 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-34003775

RESUMO

Lynch syndrome is the most common cause of hereditary colorectal cancer and is secondary to germline alterations in one of four DNA mismatch repair (MMR) genes. Here we aimed to provide novel insights into the initiation of MMR-deficient (MMRd) colorectal carcinogenesis by characterizing the expression profile of MMRd intestinal stem cells (ISC). A tissue-specific MMRd mouse model (Villin-Cre;Msh2 LoxP/LoxP ) was crossed with a reporter mouse (Lgr5-EGFP-IRES-creERT2) to trace and isolate ISCs (Lgr5+) using flow cytometry. Three different ISC genotypes (Msh2-KO, Msh2-HET, and Msh2-WT) were isolated and processed for mRNA-seq and mass spectrometry, followed by bioinformatic analyses to identify expression signatures of complete MMRd and haplo-insufficiency. These findings were validated using qRT-PCR, IHC, and whole transcriptomic sequencing in mouse tissues, organoids, and a cohort of human samples, including normal colorectal mucosa, premalignant lesions, and early-stage colorectal cancers from patients with Lynch syndrome and patients with familial adenomatous polyposis (FAP) as controls. Msh2-KO ISCs clustered together with differentiated intestinal epithelial cells from all genotypes. Gene-set enrichment analysis indicated inhibition of replication, cell-cycle progression, and the Wnt pathway and activation of epithelial signaling and immune reaction. An expression signature derived from MMRd ISCs successfully distinguished MMRd neoplastic lesions of patients with Lynch syndrome from FAP controls. SPP1 was specifically upregulated in MMRd ISCs and colocalized with LGR5 in Lynch syndrome colorectal premalignant lesions and tumors. These results show that expression signatures of MMRd ISC recapitulate the initial steps of Lynch syndrome carcinogenesis and have the potential to unveil novel biomarkers of early cancer initiation. SIGNIFICANCE: The transcriptomic and proteomic profile of MMR-deficient intestinal stem cells displays a unique set of genes with potential roles as biomarkers of cancer initiation and early progression.


Assuntos
Carcinogênese/patologia , Neoplasias Colorretais Hereditárias sem Polipose/patologia , Reparo de Erro de Pareamento de DNA , Regulação Neoplásica da Expressão Gênica , Intestinos/fisiopatologia , Células-Tronco/patologia , Transcriptoma , Animais , Apoptose , Carcinogênese/genética , Carcinogênese/metabolismo , Proliferação de Células , Neoplasias Colorretais Hereditárias sem Polipose/genética , Neoplasias Colorretais Hereditárias sem Polipose/metabolismo , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína 2 Homóloga a MutS/fisiologia , Prognóstico , Proteoma/análise , Proteoma/metabolismo , Receptores Acoplados a Proteínas G/fisiologia , Células-Tronco/metabolismo , Taxa de Sobrevida , Células Tumorais Cultivadas
11.
Gynecol Oncol ; 159(3): 869-876, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33032822

RESUMO

OBJECTIVE: Pathogenic variations in the homologous recombination (HR) gene, BRCA1 interacting protein C-terminal helicase 1 (BRIP1) increase the risk for ovarian cancer. PARP inhibitors (PARPi) exert a synthetic lethal effect in BRCA-mutated ovarian cancers. Effective HR requires cooperation between BRCA1 and BRIP1; therefore, BRIP1-incompetancy may predict vulnerability to synthetic lethality. Here we investigated the response of ovarian epithelial cells with defective BRIP1 function to PARPi, and compared these cells to those lacking BRCA1 activity. METHODS: We engineered Chinese Hamster ovarian (CHO) epithelial cells to express deficient BRIP1 or BRCA1, and exposed them to olaparib with or without carboplatin or cisplatin. We assessed cellular proliferation and survival; we calculated inhibitory concentrations and combination and reduction drug indices. RESULTS: BRIP1 and BRCA1 inactivation impedes HR activity, decreases cellular proliferation and compromises DNA damage recovery. Platinum agent exposure impairs cellular survival. Olaparib exposure alone decreases cell viability in BRCA1-deficient cells, although has no effect on BRIP1-deficient cells. Combining carboplatin or cisplatin with olaparib synergistically attenuates cellular survival, consistent with synthetic lethality. CONCLUSIONS: BRIP1-deficient ovarian epithelial cells exhibit defective HR, resulting in synthetic lethality when exposed to a platinum agent/PARPi combination. PARPi alone had no effect; this lack of effect may result from distinguishing molecular properties of BRIP1and/or consequences of genomic background. Our study identifies altered BRIP1 as a target for precision medicine-based therapies for ovarian cancers. This investigation supports consideration of the use of a platinum agent/PARPi combination in ovarian cancers depending upon genetic profile and genomic background.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Proteínas de Grupos de Complementação da Anemia de Fanconi/genética , Neoplasias Ovarianas/tratamento farmacológico , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , RNA Helicases/genética , Animais , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Proteína BRCA1/genética , Células CHO , Carboplatina/farmacologia , Carboplatina/uso terapêutico , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Cisplatino/farmacologia , Cisplatino/uso terapêutico , Cricetulus , Sinergismo Farmacológico , Proteínas de Grupos de Complementação da Anemia de Fanconi/deficiência , Feminino , Humanos , Terapia de Alvo Molecular/métodos , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/patologia , Ftalazinas/farmacologia , Ftalazinas/uso terapêutico , Piperazinas/farmacologia , Piperazinas/uso terapêutico , Inibidores de Poli(ADP-Ribose) Polimerases/uso terapêutico , Medicina de Precisão/métodos , RNA Helicases/deficiência , Reparo de DNA por Recombinação/efeitos dos fármacos , Mutações Sintéticas Letais/efeitos dos fármacos
12.
Front Microbiol ; 8: 519, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28421041

RESUMO

Areas within an agricultural field in the same season often differ in crop productivity despite having the same cropping history, crop genotype, and management practices. One hypothesis is that abiotic or biotic factors in the soils differ between areas resulting in these productivity differences. In this study, bulk soil samples collected from a high and a low productivity area from within six agronomic fields in Illinois were quantified for abiotic and biotic characteristics. Extracted DNA from these bulk soil samples were shotgun sequenced. While logistic regression analyses resulted in no significant association between crop productivity and the 26 soil characteristics, principal coordinate analysis and constrained correspondence analysis showed crop productivity explained a major proportion of the taxa variance in the bulk soil microbiome. Metagenome-wide association studies (MWAS) identified more Bradyrhizodium and Gammaproteobacteria in higher productivity areas and more Actinobacteria, Ascomycota, Planctomycetales, and Streptophyta in lower productivity areas. Machine learning using a random forest method successfully predicted productivity based on the microbiome composition with the best accuracy of 0.79 at the order level. Our study showed that crop productivity differences were associated with bulk soil microbiome composition and highlighted several nitrogen utility-related taxa. We demonstrated the merit of MWAS and machine learning for the first time in a plant-microbiome study.

13.
Plant Dis ; 97(5): 568-578, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-30722216

RESUMO

The soybean crop is one of the most important crops worldwide, as the seeds are used for both protein meal and vegetable oil. Soybean acreage covers an estimated 6% of the arable land in the world, and since the 1970s, soybean has had the highest percent increase of hectares in production compared to any other major crop. As demand for soybean continues to rise, the production area and worldwide trade are likely to increase. Biotic constraints, such as pathogens, pests, and weeds, can be detrimental to soybean production, causing significant negative impacts to yield. To successfully reduce losses caused by pathogens and pests, various practices such as cultural and seed sanitation techniques, pesticide applications, and deployment of resistance are used. For many years, public institutions have conducted regional yield trials on both private and public sector soybean cultivars. In Illinois, the University of Illinois Variety Testing Program created a public database for growers. Prompted in part by disease reports on cultivars entered into the Variety Testing Program, the Illinois Soybean Association began providing funds in 1998 to obtain additional information from regional trials to benefit growers in the state. The researchers in the Soybean Variety Testing Program conduct replicated field trials and evaluate these plots for agronomic characteristics such as height, lodging, maturity, and yield. In addition to standard yield trial data, protein and oil content are analyzed.

14.
Phytopathology ; 101(6): 750-6, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21561316

RESUMO

Infection of soybean plants with Soybean mosaic virus (SMV), which is transmitted by aphids and through seed, can cause significant reductions in seed production and quality. Because seedborne infections are the primary sources of inoculum for SMV infections in North America, host-plant resistance to seed transmission can limit the pool of plants that can serve as sources of inoculum. To examine the inheritance of SMV seed transmission in soybean, crosses were made between plant introductions (PIs) with high (PI88799), moderate (PI60279), and low (PI548391) rates of transmission of SMV through seed. In four F(2) populations, SMV seed transmission segregated as if conditioned by two or more genes. Consequently, a recombinant inbred line population was derived from a cross between PIs 88799 and 548391 and evaluated for segregation of SMV seed transmission, seed coat mottling, and simple sequence repeat markers. Chromosomal regions on linkage groups C1 and C2 were significantly associated with both transmission of isolate SMV 413 through seed and SMV-induced seed coat mottling, and explained ≈42.8 and 46.4% of the variability in these two traits, respectively. Chromosomal regions associated with seed transmission and seed coat mottling contained homologues of Arabidopsis genes DCL3 and RDR6, which encode enzymes involved in RNA-mediated transcriptional and posttranscriptional gene silencing.


Assuntos
Glycine max/virologia , Vírus do Mosaico/patogenicidade , Doenças das Plantas/virologia , Locos de Características Quantitativas/genética , Sementes/virologia , Animais , Afídeos/genética , Cruzamentos Genéticos , Genes de Plantas/genética , Repetições Minissatélites/genética , Vírus do Mosaico/genética , Filogenia , Doenças das Plantas/genética , Polimorfismo de Nucleotídeo Único , Interferência de RNA , Sementes/genética , Sementes/fisiologia , Glycine max/genética , Glycine max/fisiologia
15.
J Appl Physiol (1985) ; 110(3): 619-26, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21164152

RESUMO

Light suppresses melatonin in humans, with the strongest response occurring in the short-wavelength portion of the spectrum between 446 and 477 nm that appears blue. Blue monochromatic light has also been shown to be more effective than longer-wavelength light for enhancing alertness. Disturbed circadian rhythms and sleep loss have been described as risk factors for astronauts and NASA ground control workers, as well as civilians. Such disturbances can result in impaired alertness and diminished performance. Prior to exposing subjects to short-wavelength light from light-emitting diodes (LEDs) (peak λ = 469 nm; 1/2 peak bandwidth = 26 nm), the ocular safety exposure to the blue LED light was confirmed by an independent hazard analysis using the American Conference of Governmental Industrial Hygienists exposure limits. Subsequently, a fluence-response curve was developed for plasma melatonin suppression in healthy subjects (n = 8; mean age of 23.9 ± 0.5 years) exposed to a range of irradiances of blue LED light. Subjects with freely reactive pupils were exposed to light between 2:00 and 3:30 AM. Blood samples were collected before and after light exposures and quantified for melatonin. The results demonstrate that increasing irradiances of narrowband blue-appearing light can elicit increasing plasma melatonin suppression in healthy subjects (P < 0.0001). The data were fit to a sigmoidal fluence-response curve (R(2) = 0.99; ED(50) = 14.19 µW/cm(2)). A comparison of mean melatonin suppression with 40 µW/cm(2) from 4,000 K broadband white fluorescent light, currently used in most general lighting fixtures, suggests that narrow bandwidth blue LED light may be stronger than 4,000 K white fluorescent light for suppressing melatonin.


Assuntos
Ritmo Circadiano/fisiologia , Ritmo Circadiano/efeitos da radiação , Iluminação/métodos , Melatonina/sangue , Estimulação Luminosa/métodos , Retina/fisiologia , Retina/efeitos da radiação , Cor , Relação Dose-Resposta à Radiação , Humanos , Taxa de Depuração Metabólica/efeitos da radiação , Doses de Radiação , Semicondutores , Adulto Jovem
16.
J Parasitol ; 88(4): 657-63, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12197110

RESUMO

The parasitic copepod Neoergasilus japonicus, native to eastern Asia, was first collected from 4 species of fish (fathead minnow, Pimephales promelas; largemouth bass, Micropterus salmoides; pumpkinseed sunfish, Lepomis gibbosus; and yellow perch, Perca flavescens) in July 1994 in Saginaw Bay, Lake Huron, Michigan. Further sampling in the bay in 2001 revealed infections on 7 additional species (bluegill, Lepomis macrochirus; carp, Cyprinus carpio; channel catfish, Ictalurus punctatus; goldfish, Carassius auratus; green sunfish, Lepomis cyanellus; rock bass, Ambloplites rupestris; and smallmouth bass, Micropterus dolomieu). An additional 21 species examined in 2001 were devoid of the parasite. A limited collection of fish from Lake Superior (n = 8) and Lake Michigan (n = 46) in 1994 showed no infection. Neoergasilus japonicus is most frequently found attached to the dorsal fin and, in decreasing frequency, on the anal, tail, pelvic, and pectoral fins. Prevalence generally ranged from 15 to 70 and intensity from 1 to 10. The greatest number of copepods on a single host was 44. The copepod Neoergasilus japonicus appears to disperse over long distances rather quickly, spreading across Europe in 20 yr and then moving on to North America over a span of 10 yr. Its main vehicle of transport and introduction into the Great Lakes is probably exotic fish hosts associated with the fish-culture industry.


Assuntos
Crustáceos , Peixes/parasitologia , Animais , Carpas/parasitologia , Peixes-Gato/parasitologia , Crustáceos/anatomia & histologia , Água Doce , Great Lakes Region , Perciformes/parasitologia
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