Role of p53 in Human Cancers

TP53 codes tumor protein 53-p53 that controls the cell cycle through binding DNA directly and induces reversible cell-cycle arrest. The protein activates DNA repair genes if mutated DNA will be repaired or activates apoptotosis if the damaged DNA cannot be fixed. Therefore, p53, so-called the “guardian of the genome,” promote cell survival by allowing for DNA repair. However, the tumor-suppressor function of p53 is either lost or gained through mutations in half of the human cancers. In this work, functional perturbation of the p53 mechanism is elaborated at the breast, bladder, liver, brain, lung cancers, and osteosarcoma. Mutation of wild-type p53 not only diminishes tumor suppressor activity but transforms it into an oncogenic structure. Further, malfunction of the TP53 leads accumulation of additional oncogenic mutations in the cell genome. Thus, disruption of TP53 dependent survival pathways promotes cancer progression. This oncogenic TP53 promotes cell survival, prevents cell death through apoptosis, and contributes to the proliferation and metastasis of tumor cells. The purpose of this chapter is to discuss the contribution of mutant p53 to distinct cancer types

Budget and midrange hotel managers' perceptions of and responses to Airbnb Evidence from Istanbul

Purpos

Coping with reintermediation: the case of SMHEs

The structure of hospitality distribution has experienced profound changes within the last few decades. With the evolution and spread of internet, a substantial number of consumers started to use electronic channels for hotel bookings. This has resulted in disintermediation of traditional offline travel agencies. Yet, it has also initiated a new type of middleman to emerge and grow. Much powerful than its former version, online travel agencies (OTAs) bring about some benefits but also challenges particularly for small and medium sized independent hotels (SMHEs). This paper focuses on the difficulties SMHEs face during this transformation. The characteristics of SMHEs, the evolution of channels and the role of OTAs were discussed based on a qualitative study. 22 SMHE managers were interviewed about their perceptions of OTAs and challenges with reintermediation. Based on the data the challenges were grouped under; complexity, dependency, unfair competition and commodification. Solutions to complications of reintermediation for SMHEs and directions for future research are suggested

Who is happier among preclinical medical students: the impact of chronotype preference

tan, makbule neslisah/0000-0002-3262-7815WOS: 000533744800001PubMed: 32396746Most studies and systematic reviews of the psychological health of medical students have investigated the negative aspects of depression and anxiety. Evidence from several studies suggests depressive symptoms are common in medical school students. Moreover, evening chronotype is considered a risk factor for the development of depression. However, surprisingly no study has assessed the possible relationship between chronotypes and happiness. the aims of this study were to: (a) assess happiness and its predictors among Turkish preclinical medical students, (b) identify chronotype preferences, and (c) determine whether these predictors mediate the relationship between chronotype and happiness. Sociodemographic and clinical data collection form, Oxford Happiness Questionnaire short form (OHQ-SF), and Morningness-Eveningness Questionnaire (MEQ) were used to collect data. in this cross-sectional study, 564 students in their pre-clinical year properly completed the questionnaires. the mean age was 19.89 +/- 1.37 years (range: 17-26 years). the mean total OHQ-SF score was 23.09 +/- 4.23. Female students were significantly happier than male students (p =.042). Thirty-eight (6.7%) students were morning type, 376 (66.7%) were intermediate type, and 150 (26.6%) were evening type. the distribution of chronotypes did not differ by gender (p =.085). Evening types showed significantly lower OHQ-SF scores than morning (p <.001) and intermediate types (p <.001). MEQ scores were positively correlated with OHQ-SF scores (Pearson, r =.245, p <.001). Multivariate analyses showed that gender, perceived economic resources, physical activity, depression diagnosed the previous 12 months, stressful life events and chronotypes were predictors of happiness among Turkish preclinical medical students. These six variables explained 15% of the total variance of happiness. in conclusion, this study identified evening-type individuals showed less happiness in comparison to the morning-type and intermediate-type individuals. There was a significant relationship between happiness and chronotype, even when controlling for confounding variables, such as age, gender, and others. This information could have clinical implications and contribute to chronobiological approaches for the protection of psychological health