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1.
Genome Med ; 15(1): 55, 2023 07 20.
Artículo en Inglés | MEDLINE | ID: mdl-37475004

RESUMEN

BACKGROUND: Cyclin-dependent kinase 4/6 inhibitor (CDK4/6) therapy plus endocrine therapy (ET) is an effective treatment for patients with hormone receptor-positive/human epidermal receptor 2-negative metastatic breast cancer (HR+/HER2- MBC); however, resistance is common and poorly understood. A comprehensive genomic and transcriptomic analysis of pretreatment and post-treatment tumors from patients receiving palbociclib plus ET was performed to delineate molecular mechanisms of drug resistance. METHODS: Tissue was collected from 89 patients with HR+/HER2- MBC, including those with recurrent and/or metastatic disease, receiving palbociclib plus an aromatase inhibitor or fulvestrant at Samsung Medical Center and Seoul National University Hospital from 2017 to 2020. Tumor biopsy and blood samples obtained at pretreatment, on-treatment (6 weeks and/or 12 weeks), and post-progression underwent RNA sequencing and whole-exome sequencing. Cox regression analysis was performed to identify the clinical and genomic variables associated with progression-free survival. RESULTS: Novel markers associated with poor prognosis, including genomic scar features caused by homologous repair deficiency (HRD), estrogen response signatures, and four prognostic clusters with distinct molecular features were identified. Tumors with TP53 mutations co-occurring with a unique HRD-high cluster responded poorly to palbociclib plus ET. Comparisons of paired pre- and post-treatment samples revealed that tumors became enriched in APOBEC mutation signatures, and many switched to aggressive molecular subtypes with estrogen-independent characteristics. We identified frequent genomic alterations upon disease progression in RB1, ESR1, PTEN, and KMT2C. CONCLUSIONS: We identified novel molecular features associated with poor prognosis and molecular mechanisms that could be targeted to overcome resistance to CKD4/6 plus ET. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03401359. The trial was posted on 18 January 2018 and registered prospectively.


Asunto(s)
Neoplasias de la Mama , Humanos , Femenino , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Multiómica , Receptor ErbB-2/genética , Receptor ErbB-2/análisis , Receptor ErbB-2/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Receptores de Estrógenos/genética , Receptores de Estrógenos/análisis , Receptores de Estrógenos/uso terapéutico , Estrógenos/uso terapéutico
2.
Target Oncol ; 16(6): 773-787, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34694529

RESUMEN

BACKGROUND: Sasanlimab is a monoclonal antibody that binds to the programmed cell death receptor 1 (PD-1). Anti-PD-1 monoclonal antibodies have improved patient clinical outcomes; however, not all treated patients derive clinical benefit. Further insights on potential biomarkers beyond PD-L1 expression levels would help to identify the patients most likely to respond to treatment. OBJECTIVE: This study evaluated tumor biopsies from patients treated with intravenous or subcutaneous sasanlimab to identify biomarkers of response and characterize pharmacodynamic activity. METHODS: Anti-PD-1/PD-ligand 1 (PD-L1)-naive patients with advanced solid tumors received sasanlimab intravenously at 1, 3, or 10 mg/kg every 3 weeks (n = 23) or subcutaneously at 300 mg every 4 weeks (n = 15). Best tumor percentage change from baseline was determined by RECIST. Whole-exome DNA and RNA sequencing were performed in tumor samples collected from treated patients at protocol-defined timepoints. PD-L1 and CD8 protein expression were evaluated in tumor biopsies by immunohistochemistry. Associations with response were assessed by linear regression analysis. RESULTS: Baseline tumor mutational burden (TMB), as well as PD-L1 and CD8 expression, were significantly associated with response to sasanlimab across the multiple dose levels, routes of administration, and range of tumor types evaluated. TMB is an independent biomarker from the various tumor inflammatory genes and signatures evaluated. Gene set enrichment analysis showed that higher baseline expression levels of genes related to the interferon-γ and PD-1 signaling pathways and the cell cycle were significantly associated with response to sasanlimab across tumor types. No differences were observed between routes of administration with regard to response to sasanlimab for the biomarkers of interest (TMB, PD-L1, CD8, and interferon-γ signature). Evaluation of pharmacodynamic changes showed increased tumor expression of genes enriched in adaptive immune response pathways. CONCLUSIONS: Our findings indicate an active, immunomodulatory mechanism for the anti-PD-1 antibody sasanlimab across different tumor types and routes of administration. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT02573259; registered October 2015.


Asunto(s)
Antígeno B7-H1 , Neoplasias , Anticuerpos Monoclonales/uso terapéutico , Biomarcadores de Tumor/metabolismo , Expresión Génica , Humanos , Inhibidores de Puntos de Control Inmunológico , Interferón gamma/genética , Neoplasias/tratamiento farmacológico , Neoplasias/genética , Receptor de Muerte Celular Programada 1
3.
Nat Commun ; 11(1): 6175, 2020 12 02.
Artículo en Inglés | MEDLINE | ID: mdl-33268821

RESUMEN

To elucidate the effects of neoadjuvant chemotherapy (NAC), we conduct whole transcriptome profiling coupled with histopathology analyses of a longitudinal breast cancer cohort of 146 patients including 110 pairs of serial tumor biopsies collected before treatment, after the first cycle of treatment and at the time of surgery. Here, we show that cytotoxic chemotherapies induce dynamic changes in the tumor immune microenvironment that vary by subtype and pathologic response. Just one cycle of treatment induces an immune stimulatory microenvironment harboring more tumor infiltrating lymphocytes (TILs) and up-regulation of inflammatory signatures predictive of response to anti-PD1 therapies while residual tumors are immune suppressed at end-of-treatment compared to the baseline. Increases in TILs and CD8+ T cell proportions in response to NAC are independently associated with pathologic complete response. Further, on-treatment immune response is more predictive of treatment outcome than immune features in paired baseline samples although these are strongly correlated.


Asunto(s)
Antígeno B7-H1/genética , Neoplasias de la Mama/tratamiento farmacológico , Carcinoma Ductal de Mama/tratamiento farmacológico , Regulación Neoplásica de la Expresión Génica , Linfocitos Infiltrantes de Tumor/efectos de los fármacos , Terapia Neoadyuvante/métodos , Antraciclinas/uso terapéutico , Antígeno B7-H1/antagonistas & inhibidores , Antígeno B7-H1/inmunología , Neoplasias de la Mama/genética , Neoplasias de la Mama/inmunología , Neoplasias de la Mama/mortalidad , Linfocitos T CD8-positivos/efectos de los fármacos , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/patología , Carcinoma Ductal de Mama/genética , Carcinoma Ductal de Mama/inmunología , Carcinoma Ductal de Mama/mortalidad , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/inmunología , Ciclofosfamida/uso terapéutico , Supervivencia sin Enfermedad , Docetaxel/uso terapéutico , Receptor alfa de Estrógeno/genética , Receptor alfa de Estrógeno/inmunología , Femenino , Perfilación de la Expresión Génica , Humanos , Inmunidad Innata , Factores Reguladores del Interferón/genética , Factores Reguladores del Interferón/inmunología , Estudios Longitudinales , Linfocitos Infiltrantes de Tumor/inmunología , Linfocitos Infiltrantes de Tumor/patología , Neoplasia Residual , Receptor ErbB-2/genética , Receptor ErbB-2/inmunología , Trastuzumab/uso terapéutico , Resultado del Tratamiento , Microambiente Tumoral/efectos de los fármacos , Microambiente Tumoral/genética , Microambiente Tumoral/inmunología
4.
Br J Cancer ; 122(11): 1630-1637, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32238921

RESUMEN

BACKGROUND: In this first-in-human, Phase 1 study of a microRNA-based cancer therapy, the recommended Phase 2 dose (RP2D) of MRX34, a liposomal mimic of microRNA-34a (miR-34a), was determined and evaluated in patients with advanced solid tumours. METHODS: Adults with various solid tumours refractory to standard treatments were enrolled in 3 + 3 dose-escalation cohorts and, following RP2D determination, expansion cohorts. MRX34, with oral dexamethasone premedication, was given intravenously daily for 5 days in 3-week cycles. RESULTS: Common all-cause adverse events observed in 85 patients enrolled included fever (% all grade/G3: 72/4), chills (53/14), fatigue (51/9), back/neck pain (36/5), nausea (36/1) and dyspnoea (25/4). The RP2D was 70 mg/m2 for hepatocellular carcinoma (HCC) and 93 mg/m2 for non-HCC cancers. Pharmacodynamic results showed delivery of miR-34a to tumours, and dose-dependent modulation of target gene expression in white blood cells. Three patients had PRs and 16 had SD lasting ≥4 cycles (median, 19 weeks, range, 11-55). CONCLUSION: MRX34 treatment with dexamethasone premedication demonstrated a manageable toxicity profile in most patients and some clinical activity. Although the trial was closed early due to serious immune-mediated AEs that resulted in four patient deaths, dose-dependent modulation of relevant target genes provides proof-of-concept for miRNA-based cancer therapy. CLINICAL TRIAL REGISTRATION: NCT01829971.


Asunto(s)
Antineoplásicos/administración & dosificación , Antineoplásicos/efectos adversos , MicroARNs/administración & dosificación , MicroARNs/efectos adversos , Neoplasias/tratamiento farmacológico , Adulto , Anciano , Anciano de 80 o más Años , Antineoplásicos/farmacocinética , Femenino , Humanos , Liposomas/efectos adversos , Liposomas/farmacocinética , Masculino , Dosis Máxima Tolerada , MicroARNs/farmacocinética , Persona de Mediana Edad , Nanopartículas/administración & dosificación , Nanopartículas/efectos adversos
5.
Gynecol Oncol ; 150(2): 318-323, 2018 08.
Artículo en Inglés | MEDLINE | ID: mdl-29929922

RESUMEN

OBJECTIVE: To assess the performance of a symptom index (SI) and multivariate biomarker panel in the identification of ovarian cancer in women presenting for surgery with an adnexal mass. STUDY DESIGN: Prospective study of patients seen at a tertiary medical center. Following consent, patients completed an SI and preoperative serum was collected for individual markers (CA 125) and a second-generation FDA-cleared biomarker test (MIA2G). Results for the SI and MIA2G were correlated with operative findings and surgical pathology. Logistic regression modeling was performed to assess the interaction of the SI with MIA2G to determine the risk of malignancy (ROM). RESULTS: Of the 218 patients enrolled, the mean age was 53.6 years (range 18-86). One-hundred and forty-seven patients (67.4%) were postmenopausal. Sixty-four patients (29.4%) had epithelial ovarian cancer or fallopian tube cancer (EOC/FTC) and 17 (7.8%) had borderline ovarian tumors. A positive SI or MIA2G correctly identified 96.1% of patients with EOC/FTC. Using logistic regression, we found that both SI and MIA2G score were significantly associated with ROM (p < 0.001). In a simulation with disease prevalence set at 5%, patients with a negative SI and a MIA2G score of 6 had a ROM of 1.8% whereas patients with the same MIA2G and positive SI had a 10.5% ROM, nearly a 6-fold higher risk. CONCLUSIONS: The combination of a patient-reported symptom index and refined biomarker panel allows for improved accuracy in the assessment for ovarian cancer in patients with an adnexal mass. This strategy could offer a personalized approach to addressing ROM to triage patients with an adnexal mass to appropriate care.


Asunto(s)
Anexos Uterinos/patología , Enfermedades de los Anexos/sangre , Biomarcadores de Tumor/sangre , Neoplasias Ováricas/sangre , Enfermedades de los Anexos/patología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Modelos Logísticos , Persona de Mediana Edad , Neoplasias Ováricas/metabolismo , Neoplasias Ováricas/patología , Valor Predictivo de las Pruebas , Adulto Joven
6.
Int J Gynecol Cancer ; 27(2): 233-238, 2017 02.
Artículo en Inglés | MEDLINE | ID: mdl-27870706

RESUMEN

OBJECTIVE: This study aimed to evaluate the predictive ability of a multivariate biomarker test in combination with a symptom index (SI) to identify ovarian cancer in a cohort of women planning to undergo surgery for a pelvic mass. METHODS: This was a prospective study of patients seen at a tertiary care medical center. Following consent, patients completed an SI and preoperative serum was collected for a Food and Drug Administration-cleared multivariate biomarker test [multivariate index assay (MIA)]. Results for the SI and MIA were correlated with operative findings and surgical pathology. RESULTS: Of 218 patients enrolled, 124 (56.9%) had benign disease and 94 (43.1%) had borderline tumors or carcinomas. Sixty-six patients had a primary ovarian or fallopian tube cancer. The median age of patients enrolled in this study was 54 years (interquartile range, 44-63 years), of whom 148 (67.9%) were postmenopausal. More than a third (36.3%) of patients with benign masses was accurately identified as low risk by MIA and SI. The sensitivity and negative predictive value (NPV) of the SI relative to primary ovarian cancer was 87.9% (95% CI, 77.9%-93.7%) and 91.6% (95% CI, 84.3%-95.7%), respectively. The sensitivity and NPV of CA125 was 75.4% (95% CI, 63.7%-84.2%) and 86.4% (95% CI, 79.1%-91.5%), respectively, and the sensitivity and NPV of the MIA were 93.9% (95% CI, 85.4%-97.6%) and 94.5% (95% CI, 94.5%-100%), respectively. The overall sensitivity for the combination of MIA plus SI was 100% (66/66; 95% CI, 94.5%-100%), and specificity was 36.3% (45/124; 95% CI, 28.4%-45.0%), with an NPV of 100% (95% CI, 92.1%-100%). CONCLUSIONS: The addition of a patient-reported SI, which captures subjective symptoms in an objective manner, improved the sensitivity of MIA across all stages and subtypes of ovarian cancer.


Asunto(s)
Biomarcadores de Tumor/sangre , Neoplasias Ováricas/sangre , Neoplasias Ováricas/diagnóstico , Adulto , Femenino , Humanos , Persona de Mediana Edad , Neoplasias Ováricas/patología , Valor Predictivo de las Pruebas , Estudios Prospectivos , Reproducibilidad de los Resultados , Índice de Severidad de la Enfermedad
7.
Med Care ; 55(3): 244-251, 2017 03.
Artículo en Inglés | MEDLINE | ID: mdl-27787351

RESUMEN

BACKGROUND: Opportunities to leverage observational data for precision medicine research are hampered by underlying sources of bias and paucity of methods to handle resulting uncertainty. We outline an approach to account for bias in identifying comorbid associations between 2 rare genetic disorders and type 2 diabetes (T2D) by applying a positive and negative control disease paradigm. RESEARCH DESIGN: Association between 10 common and 2 rare genetic disorders [Hereditary Fructose Intolerance (HFI) and α-1 antitrypsin deficiency] and T2D was compared with the association between T2D and 7 negative control diseases with no established relationship with T2D in 4 observational databases. Negative controls were used to estimate how much bias and variance existed in datasets when no effect should be observed. RESULTS: Unadjusted association for common and rare genetic disorders and T2D was positive and variable in magnitude and distribution in all 4 databases. However, association between negative controls and T2D was 200% greater than expected indicating the magnitude and confidence intervals for comorbid associations are sensitive to systematic bias. A meta-analysis using this method demonstrated a significant association between HFI and T2D but not for α-1 antitrypsin deficiency. CONCLUSIONS: For observational studies, when covariate data are limited or ambiguous, positive and negative controls provide a method to account for the broadest level of systematic bias, heterogeneity, and uncertainty. This provides greater confidence in assessing associations between diseases and comorbidities. Using this approach we were able to demonstrate an association between HFI and T2D. Leveraging real-world databases is a promising approach to identify and corroborate potential targets for precision medicine therapies.


Asunto(s)
Comorbilidad , Diabetes Mellitus Tipo 2/epidemiología , Intolerancia a la Fructosa/epidemiología , Estudios Observacionales como Asunto/métodos , Deficiencia de alfa 1-Antitripsina/epidemiología , Bases de Datos Factuales , Humanos , Proyectos de Investigación
8.
J Clin Endocrinol Metab ; 101(3): 945-52, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26672639

RESUMEN

CONTEXT: The relationship between rising body mass index (BMI) and prospective risk of nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH) is virtually absent. OBJECTIVE: Determine the extent of the association between BMI and risk of future NAFLD diagnosis, stratifying by sex and diabetes. DESIGN: Two prospective studies using Humedica and Health Improvement Network (THIN) with 1.54 and 4.96 years of follow-up, respectively. SETTING: Electronic health record databases. PARTICIPANTS: Patients with a recorded BMI measurement between 15 and 60 kg/m(2), and smoking status, and 1 year of active status before baseline BMI. Patients with a diagnosis or history of chronic diseases were excluded. INTERVENTIONS: None. MAIN OUTCOME MEASURE: Recorded diagnosis of NAFLD/NASH during follow-up (Humedica International Classification of Diseases, Ninth Revision code 571.8, and read codes for NAFLD and NASH in THIN). RESULTS: Hazard ratios (HRs) were calculated across BMI categories using BMI of 20-22.5 kg/m(2) as the reference category, adjusting for age, sex, and smoking status. Risk of recorded NAFLD/NASH increased linearly with BMI and was approximately 5-fold higher in Humedica (HR = 4.78; 95% confidence interval, 4.17-5.47) and 9-fold higher in THIN (HR = 8.93; 7.11-11.23) at a BMI of 30-32.5 kg/m(2) rising to around 10-fold higher in Humedica (HR = 9.80; 8.49-11.32) and 14-fold higher in THIN (HR = 14.32; 11.04-18.57) in the 37.5- to 40-kg/m(2) BMI category. Risk of NAFLD/NASH was approximately 50% higher in men and approximately double in those with diabetes. CONCLUSIONS: These data quantify the consistent and strong relationships between BMI and prospectively recorded diagnoses of NAFLD/NASH and emphasize the importance of weight reduction strategies for prevention and management of NAFLD.


Asunto(s)
Índice de Masa Corporal , Enfermedad del Hígado Graso no Alcohólico/epidemiología , Adulto , Complicaciones de la Diabetes/epidemiología , Registros Electrónicos de Salud , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Factores de Riesgo , Factores Sexuales , Fumar/epidemiología
9.
PLoS One ; 9(5): e97139, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24858947

RESUMEN

Hyperglycemia resulting from type 2 diabetes mellitus (T2DM) is the main cause of diabetic complications such as retinopathy and neuropathy. A reduction in hyperglycemia has been shown to prevent these associated complications supporting the importance of glucose control. Glucokinase converts glucose to glucose-6-phosphate and determines glucose flux into the ß-cells and hepatocytes. Since activation of glucokinase in ß-cells is associated with increased risk of hypoglycemia, we hypothesized that selectively activating hepatic glucokinase would reduce fasting and postprandial glucose with minimal risk of hypoglycemia. Previous studies have shown that hepatic glucokinase overexpression is able to restore glucose homeostasis in diabetic models; however, these overexpression experiments have also revealed that excessive increases in hepatic glucokinase activity may also cause hepatosteatosis. Herein we sought to evaluate whether liver specific pharmacological activation of hepatic glucokinase is an effective strategy to reduce hyperglycemia without causing adverse hepatic lipids changes. To test this hypothesis, we evaluated a hepatoselective glucokinase activator, PF-04991532, in Goto-Kakizaki rats. In these studies, PF-04991532 reduced plasma glucose concentrations independent of changes in insulin concentrations in a dose-dependent manner both acutely and after 28 days of sub-chronic treatment. During a hyperglycemic clamp in Goto-Kakizaki rats, the glucose infusion rate was increased approximately 5-fold with PF-04991532. This increase in glucose infusion can be partially attributed to the 60% reduction in endogenous glucose production. While PF-04991532 induced dose-dependent increases in plasma triglyceride concentrations it had no effect on hepatic triglyceride concentrations in Goto-Kakizaki rats. Interestingly, PF-04991532 decreased intracellular AMP concentrations and increased hepatic futile cycling. These data suggest that hepatoselective glucokinase activation may offer glycemic control without inducing hepatic steatosis supporting the evaluation of tissue specific activators in clinical trials.


Asunto(s)
Diabetes Mellitus Experimental/complicaciones , Activadores de Enzimas/farmacología , Glucoquinasa/metabolismo , Hiperglucemia/complicaciones , Hiperglucemia/tratamiento farmacológico , Imidazoles/farmacología , Hígado/efectos de los fármacos , Hígado/enzimología , Ácidos Nicotínicos/farmacología , Animales , Activadores de Enzimas/efectos adversos , Activadores de Enzimas/uso terapéutico , Glucosa/metabolismo , Hepatocitos/efectos de los fármacos , Hepatocitos/metabolismo , Imidazoles/efectos adversos , Imidazoles/uso terapéutico , Hígado/patología , Masculino , Ácidos Nicotínicos/efectos adversos , Ácidos Nicotínicos/uso terapéutico , Enfermedad del Hígado Graso no Alcohólico/inducido químicamente , Especificidad de Órganos , Ratas
10.
Toxicol Sci ; 131(1): 292-301, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22982684

RESUMEN

Cardiotoxicity is one of the leading causes of drug attrition. Current in vitro models insufficiently predict cardiotoxicity, and there is a need for alternative physiologically relevant models. Here we describe the gene expression profile of human-induced pluripotent stem cell-derived cardiocytes (iCC) postthaw over a period of 42 days in culture and compare this profile to human fetal and adult as well as adult cynomolgus nonhuman primate (NHP, Macaca fascicularis) heart tissue. Our results indicate that iCC express relevant cardiac markers such as ion channels (SCN5A, KCNJ2, CACNA1C, KCNQ1, and KCNH2), tissue-specific structural markers (MYH6, MYLPF, MYBPC3, DES, TNNT2, and TNNI3), and transcription factors (NKX2.5, GATA4, and GATA6) and lack the expression of stem cell markers (FOXD3, GBX2, NANOG, POU5F1, SOX2, and ZFP42). Furthermore, we performed a functional evaluation of contractility of the iCC and showed functional and pharmacological correlations with myocytes isolated from adult NHP hearts. These results suggest that stem cell-derived cardiocytes may represent a novel in vitro model to study human cardiac toxicity with potential ex vivo and in vivo translation.


Asunto(s)
Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos , Miocardio/metabolismo , Miocitos Cardíacos/efectos de los fármacos , Células Madre Pluripotentes/citología , Transcriptoma/efectos de los fármacos , Animales , Señalización del Calcio/efectos de los fármacos , Técnicas de Cultivo de Célula , Diferenciación Celular , Evaluación Preclínica de Medicamentos , Perfilación de la Expresión Génica , Humanos , Macaca fascicularis , Miocitos Cardíacos/metabolismo
11.
J Avian Med Surg ; 27(4): 285-93, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24640930

RESUMEN

Handling, including blood collection, has often been discouraged in molting penguins because it is considered an additional stress imposed on birds already experiencing major physiologic stress associated with molting. To evaluate the degree of physiologic stress posed by molting, we compared the hematologic and plasma biochemical values and hormone levels of molting and nonmolting African penguins, Spheniscus demersus. Five male and 5 female penguins randomly chosen were given complete physical examinations, were weighed, and blood samples were taken at 7 time points before, during, and after the molt. Data were analyzed by linear mixed-model analysis of variance. Throughout the study, behavior and appetite remained normal. Catecholamine levels were highly variable within and among subjects, whereas mean corticosterone levels were significantly different between baseline, molt, and postmolt values. Significant differences from baseline values were observed in many of the hematologic analytes; however, only decreases in hematocrit and red blood cell count values were considered clinically significant. Anemia due to experimentally induced blood loss as a possible cause of the significant hematologic changes was ruled out based on results of a follow-up control study during the nonmolt season, which showed no significant changes in hematocrit level or total red blood cell counts when using similar sampling protocols, which indicates that these changes were associated with molt.


Asunto(s)
Muda/fisiología , Spheniscidae/sangre , Spheniscidae/fisiología , Animales , Análisis Químico de la Sangre/veterinaria , Catecolaminas/sangre , Catecolaminas/metabolismo , Plumas , Femenino , Masculino , Valores de Referencia , Estrés Fisiológico/fisiología
12.
Bioinformatics ; 27(3): 359-67, 2011 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-21148161

RESUMEN

MOTIVATION: We propose a Bayesian ensemble method for survival prediction in high-dimensional gene expression data. We specify a fully Bayesian hierarchical approach based on an ensemble 'sum-of-trees' model and illustrate our method using three popular survival models. Our non-parametric method incorporates both additive and interaction effects between genes, which results in high predictive accuracy compared with other methods. In addition, our method provides model-free variable selection of important prognostic markers based on controlling the false discovery rates; thus providing a unified procedure to select relevant genes and predict survivor functions. RESULTS: We assess the performance of our method several simulated and real microarray datasets. We show that our method selects genes potentially related to the development of the disease as well as yields predictive performance that is very competitive to many other existing methods. AVAILABILITY: http://works.bepress.com/veera/1/.


Asunto(s)
Teorema de Bayes , Perfilación de la Expresión Génica/métodos , Análisis de Secuencia por Matrices de Oligonucleótidos/métodos , Neoplasias Encefálicas/genética , Neoplasias de la Mama/genética , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Modelos Genéticos , Análisis de Supervivencia
13.
Evol Dev ; 7(5): 429-39, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-16174036

RESUMEN

The rodent mandible has become a paradigm for studies on the development and evolution of complex morphological structures. We use a combination of geometric and multivariate morphometric methods in order to assess the correspondence between integration patterns and a priori biological models in the context of evolutionary shape divergence in the mandible of rodents of the family Echimyidae. The correlation of shape distances among operational taxonomic units (individuals, species, genera) in separate morphogenetic components allowed the construction of integration matrices among mandible components for data sets corresponding to varying levels of genetic divergence (intergeneric, interspecific, and intrapopulational). The integration matrices were associated with a priori biological (developmental, genetical, modular) models, and the maximum integration axes (singular warps) were compared with realized axes of maximum interspecific variation (relative warps). The integration pattern and intensity were not stable in data sets with different levels of genetic divergence, and the varying functional demands during the ecological radiation in the family were probably responsible for the differences in observed integration patterns. Developmental and genetic models were significantly associated with the interspecific integration patterns observed, suggesting a role for neutral evolution during the evolutionary divergence of mandible shape. However, directional and stabilizing selection were not discarded as processes responsible for the generation of interspecific integration. The choreography of the morphogenetic components in the mandible is highly flexible and the integrated groups of components can be reorganized depending on functional demands during evolutionary shape changes.


Asunto(s)
Mandíbula/anatomía & histología , Filogenia , Animales , Modelos Biológicos , Ratas
14.
Naturwissenschaften ; 89(8): 357-60, 2002 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-12435036

RESUMEN

Most harvestmen are nocturnal, nonacoustical, and nonvisual arthropods. They have a pair of exocrine glands on the cephalothorax that produce defensive volatile secretions. We investigated in the field the possible alarm effect of these secretions in the gregarious harvestman Goniosoma aff. proximum. A cotton swab soaked with the species' own exudate (treatment), or with water (control), was held 1-2 cm from the center of harvestmen aggregations. The results showed that the gland secretion elicits an alarm response in Goniosoma: whereas 73.3% of the aggregations dispersed after being stimulated with the gland exudate, only 3.3% responded to the water control. Respondent groups are larger than nonrespondent groups, and the time of reaction to the secretion was inversely related to group size. This is the first demonstration of a chemically-mediated alarm effect in harvestmen. The alarm response in gregarious harvestmen has possibly evolved as a by-product of a primarily defensive reaction in the context of predator avoidance. The discovery of this novel function of scent-gland secretion is meaningful in view of the widespread occurrence of gregarious habit among species of the order Opiliones.


Asunto(s)
Arácnidos/fisiología , Glándulas Odoríferas/metabolismo , Animales , Comunicación
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