RESUMO
Epigenetic silencing of O-6-methylguanine-DNA methyltransferase (MGMT) promoter via methylation in a glioblastoma (GBM), has been correlated with a more favourable response to alkylating chemotherapeutic agents such as temozolomide. The use of global methylation surrogates such as Long Interspersed Nucleotide Element 1 (LINE1) may also be valuable in order to fully understand these highly heterogeneous tumours. In this study, we analysed both original and recurrent GBMs in 22 patients (i.e. 44 tumours), for both MGMT and LINE1 methylation status. In the 22 patients: 14 (63.6%) displayed MGMT methylation stability in the recurrent GBM versus 8 (36.4%), with instability of methylation status. No significant differences in overall and progression free survival was evident between these two groups. LINE1 methylation status remained stable for 12 (54.5%) of recurrent GBM patients versus 9 (41%) of the patients with instability in LINE1 methylation status (p = 0.02), resulting in an increase in overall survival of the stable LINE1 group (p = 0.04). The results obtained demonstrated major epigenetic instability of GBMs treated with temozolomide as part of the STUPP protocol. GBMs appear to undergo selective evolution post-treatment, and have the ability to recur with a newly reprogrammed epigenetic status. Selective targeting of the altered epigenomes in recurrent GBMs may facilitate the future development of both prognostic biomarkers and enhanced therapeutic strategies.
Assuntos
Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/terapia , Metilação de DNA , Metilases de Modificação do DNA/metabolismo , Enzimas Reparadoras do DNA/metabolismo , Glioblastoma/metabolismo , Glioblastoma/terapia , Proteínas Supressoras de Tumor/metabolismo , Adulto , Idoso , Protocolos Antineoplásicos , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Neoplasias Encefálicas/genética , Metilases de Modificação do DNA/genética , Enzimas Reparadoras do DNA/genética , Feminino , Glioblastoma/genética , Humanos , Isocitrato Desidrogenase/genética , Isocitrato Desidrogenase/metabolismo , Masculino , Pessoa de Meia-Idade , Recidiva , Resultado do Tratamento , Proteínas Supressoras de Tumor/genética , Adulto JovemRESUMO
BACKGROUND: Heart rate variability (HRV) is known to be reduced in depression; however, is unclear whether this is a consequence of the disorder or due to antidepressant medication. METHODS: We analysed data on 4750 participants from the first wave of The Irish Longitudinal Study on Ageing (TILDA). Time [standard deviation of normal to normal intervals (SDNN ms2)] and frequency domain [low frequency (LF) and high frequency (HF)] measures of HRV were derived from 3-lead surface electrocardiogram records obtained during 10 min of supine rest. Depression was assessed using the Center for Epidemiologic Studies - Depression scale. RESULTS: Participants on antidepressants [with (n = 80) or without depression (n = 185)] differed significantly from controls (not depressed and not taking antidepressants n = 4107) on all measures of HRV. Depressed participants not taking antidepressants (n = 317) did not differ from controls on any measures of HRV. In linear regression analysis adjusted for relevant factors all antidepressants were associated with lower measures HRV. Participants on selective serotonin reuptake inhibitors (SSRIs) had higher measures of HRV relative to participants on tricyclic antidepressants or serotonin-norepinephrine reuptake inhibitors respectively. CONCLUSIONS: Our results suggest that reductions in HRV observed among depressed older adults are driven by the effects of antidepressant medications. SSRIs have less impact on HRV than other antidepressants but they are still associated with lower measures of HRV. Study limitations include the use of a self-report measure of depression and floor effects of age on HRV could have limited our ability to detect an association between HRV and depression.
Assuntos
Antidepressivos de Segunda Geração/uso terapêutico , Antidepressivos Tricíclicos/uso terapêutico , Depressão/tratamento farmacológico , Frequência Cardíaca/efeitos dos fármacos , Inibidores Seletivos de Recaptação de Serotonina/uso terapêutico , Idoso , Eletrocardiografia , Feminino , Humanos , Irlanda , Modelos Lineares , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Inquéritos e QuestionáriosRESUMO
INTRODUCTION: Computed tomography (CT) imaging has become indispensable in the management of medical oncology patients. Risks associated with high cumulative effective dose (CED) are relevant in testicular cancer patients. Split-bolus protocols, whereby the contrast medium injection is divided into two, followed by combining the required phase images in a single scan acquisition has been shown to provide images of comparable image quality and less radiation dose compared to single-bolus split-phase CT for various indications. We retrospectively evaluated the performance of split-bolus and single-bolus protocols in patients having follow-up CT imaging for testicular cancer surveillance. METHODS: 45 patients with testicular cancer undergoing surveillance CT imaging of the thorax, abdomen, and pelvis who underwent split-bolus and single-bolus protocols were included. Quantitative image quality analysis was conducted by placing region of interests in pre-defined anatomical sub-structures within the abdominal cavity. The signal-to-noise ratio (SNR) and radiation dose in the form of dose length product (DLP) and effective dose (ED) were recorded. RESULTS: The DLP and ED for the single-bolus, split-phase acquisition was 506 ± 89 mGy cm and 7.59 ± 1.3 mSv, respectively. For the split-bolus, single-phase acquisition, 397 ± 94 mGy∗cm and 5.95 ± 1.4 mSv, respectively (p < 0.000). This represented a 21.5 % reduction in radiation dose exposure. The SNR for liver, muscle and fat for the single-bolus were 7.4, 4.7 and 8, respectively, compared to 5.5, 3.8 and 7.4 in the split-bolus protocol (p < 0.001). CONCLUSION: In a testicular cancer patient cohort undergoing surveillance CT imaging, utilization of a split-bolus single-phase acquisition CT protocol enabled a significant reduction in radiation dose whilst maintaining subjective diagnostic acceptability. IMPLICATIONS FOR PRACTICE: Use of split-bolus, single-phase acquisition has the potential to reduce CED in surveillance of testicular cancer patients.
Assuntos
Neoplasias Embrionárias de Células Germinativas , Neoplasias Testiculares , Masculino , Humanos , Estudos Retrospectivos , Neoplasias Testiculares/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Meios de ContrasteRESUMO
Turkey liver xanthine dehydrogenase containing the full complement of molybdenum, flavin and iron-sulphur prosthetic groups is, as normally isolated, a mixture of functional and non-functional enzyme. The latter apparently lacks the cyanolysable persulphide groups essential to the oxidation of xanthine and to interaction with arsenite. These groups are not required for the oxidation of NADH by Methylene Blue. That KI treatment effects a differential release of flavin from xanthine-prereduced and NADH-prereduced enzyme merely reflects the degree of functionality of the preparations used and may not be taken as evidence for non-equivalence of the flavin chromophores.
Assuntos
Cetona Oxirredutases , Fígado/enzimologia , Xantina Desidrogenase , Animais , Arsênio , Sítios de Ligação , Cianetos , Flavinas , Ferro , Molibdênio , Enxofre , Tiocianatos , Perus , Xantina Desidrogenase/antagonistas & inibidoresRESUMO
Puppy hearts were engrafted to C6-deficient rabbits, and also to complement-sufficient animals in order to determine the influence of the sixth component of complement on xenograft rejection. Delayed rejection was observed in the puppy hearts engrafted to the C6-deficient animals indicating that complement sufficiency of C6 is required for hyperacute xenograft rejection.