Mutations in the BRAF gene have recently been detected in a wide range of neoplastic lesions with a particularly high prevalence in melanoma and papillary thyroid carcinoma (PTC). The hot-spot mutation BRAF(V599E) is frequently detected in PTC (36-69%), in contrast to its absence in other benign or malignant thyroid lesions. In order to unravel whether there is any association between the occurrence of the BRAF mutation and the histological pattern of PTC, in this study a previous series of 50 PTCs was extended to 134 cases, including ten cases of PTC-related entities-hyalinizing trabecular tumour (HTT) and mucoepidermoid carcinoma (MEC). Using PCR/SSCP and sequencing, the BRAF(V599E) mutation was detected in 45 of the 124 PTCs (36%). No mutations were detected in any case of HTT and MEC. BRAF(V599E) was present in 75% of Warthin-like PTCs and 53% of conventional PTCs, whereas no BRAF(V599E) mutations were detected in any of the 32 cases of the follicular variant of PTC. BRAF(V599E) was also detected in 6 of 11 cases of the oncocytic variant of PTC that displayed a papillary or mixed follicular-papillary growth pattern and in none of the four oncocytic PTCs with a follicular growth pattern. A distinct mutation in BRAF (codon K600E) was detected in three cases of the follicular variant of PTC. This study has confirmed the high prevalence of BRAF(V599E) in PTC and has shown that the mutation is almost exclusively seen in PTC with a papillary or mixed follicular-papillary growth pattern, regardless of the cytological features of the neoplastic cells. The results support the existence of an oncocytic variant of PTC that should be separated from the oncocytic variant of follicular carcinoma and suggest that the follicular variant of PTC may be genetically different from conventional PTC.
Background During COVID-19 pandemic, healthcare workers (HCWs) have had high workload and have been exposed to multiple psychosocial stressors. The aim of this study was to evaluate HCWs in terms of the relative contributions of socio-demographic and mental health variables on three burnout dimensions: personal, work-related, and client-related burnout. Methods A cross-sectional study was performed using an online questionnaire spread via social networks. A snowball technique supported by health care institutions and professional organizations was applied. Results A total of 2008 subjects completed the survey. Gender, parental status, marriage status, and salary reduction were found to be significant factors for personal burnout. Health problems and direct contact with infected people were significantly associated with more susceptibility to high personal and work-related burnout. Frontline working positions were associated with all three dimensions. Higher levels of stress and depression in HCWs were significantly associated with increased levels of all burnout dimensions. Higher levels of satisfaction with life and resilience were significantly associated with lower levels of all burnout dimensions. Conclusions All three burnout dimensions were associated with a specific set of covariates. Consideration of these three dimensions is important when designing future burnout prevention programs for HCWs.
PurposeThe main purpose of this paper is to investigate the relationship of job attitudes to personality traits in a hospitality setting.Design/methodology/approachThe author uses a questionnaire at two hotel chains in the western US to ascertain the variables. Employees that are surveyed are all non‐management personnel.FindingsThe author finds that job attitudes, specifically, organizational commitment and job satisfaction are significantly related to the personality traits, the big five and locus of control.Research limitations/implicationsThe number of hotel employees studied is 159. A larger sample size could increase the validity of the findings.Practical implicationsThis paper encourages hotel management to consider the use of personality tests in the selection of hotel employees as the results suggest that certain traits are related to an employee's job satisfaction and organizational commitment.Originality/valueThe paper is original in the sense that prior work has mainly focused on the employee job attitude in relation to how the employee perceives the workplace. There have been limited investigations into the relationship between personality and job attitudes. This paper suggests that dispositions may play a role in the attitude of the employee.
Two theories have emerged in the managerial control literature as to the best way for organizations to ensure that managers are acting in the firm's best interest: agency theory, which stresses controlling decision-makers through monitoring and incentives aligned with organizational goals, and stewardship theory, which stresses that decision-makers will act in the organization's best interest even in the absence of controls. Much of the research investigating the utility of these two positions is based on archival data where actual decision-making can only be inferred. In this study, we utilize a laboratory methodology in order to determine if decision-makers actually make different decisions when under the types of control (or lack thereof) suggested in these two theories. The results of this study show that individuals under agency controls invest more in alternatives that maximize profits of an organization than individuals under stewardship controls. Copyright 2003 Blackwell Publishing Ltd..
Solid cell nests of the human thyroid gland are composed of main cells and C cells. In order to investigate the putative stem cell nature of the role for solid cell nests, we evaluated the histological features, and the immunohistochemical expression of p63, bcl-2, telomerase catalytic subunit, and two proliferative markers (Ki-67 and minichromosome maintenance protein 2), in a series of 24 cases of solid cell nests. Proliferative indices were determined in (a) solid cell nests, (b) thyroid follicular cells in the vicinity of solid cell nests within a low-power field, and (c) distant thyroid tissue, at a distance of at least three low-power fields from solid cell nests. In 15 cases of solid cell nests (62.5%), mixed follicles were observed; papillary formations were observed in four cases (16.6%), and ciliated cells were observed in the lining of microcysts associated with two cases (8.3%). Salivary gland-type tissue, cartilage islands, adipose and fibrous tissues, and small nerves were also associated with some cases of solid cell nests. We observed that the main cells of the solid cell nests express consistently telomerase, although at lower levels than p63, and show strong cytoplasmic immunoreactivity for bcl-2, which is associated with an increased differentiation potential. We also observed that despite their relative low proliferative index, main cells of the solid cell nests display higher proliferation than follicular cells in the vicinity and follicular cells in more distant thyroid tissue. We conclude that main cells of the solid cell nests apparently harbor the minimal properties of a stem cell phenotype (capacity for both self-renewal, conferred by telomerase activity, and differentiation to one or more than one type of specialized cells, given by the high expression of p63 and bcl-2) and may thus represent a pool of stem cells of the adult thyroid.
Background-Heart failure has been associated with impaired cardiac sympathetic neuronal function. Cardiac imaging with radiolabeled agents that are substrates for the neuronal norepinephrine transporter (NET) has demonstrated the potential to identify individuals at risk of cardiac events. N- 18 F]fluoro-propoxy)-benzyl]-guanidine (LMI1195) is a newly developed 18 F-labeled NET substrate designed to allow cardiac neuronal imaging with the high sensitivity, resolution, and quantification afforded by positron emission tomography (PET). Methods and Results-LMI1195 was evaluated in comparison with norepinephrine (NE) in vitro and 123 I-metaiodobenzylguanidine (MIBG) in vivo. The affinity (K i ) of LMI1195 for NET was 5.16Ϯ2.83 mol/L, similar to that of NE (3.36Ϯ2.77 mol/L) in a cell membrane-binding assay. Similarly, LMI1195 uptake kinetics examined in a human neuroblastoma cell line had K m and V max values of 1.44Ϯ0.76 mol/L and 6.05Ϯ3.09 pmol/million cells per minute, comparable to NE (2.01Ϯ0.85 mol/L and 6.23Ϯ1.52 pmol/million cells per minute). In rats, LMI1195 heart uptake at 15 and 60 minutes after intravenous administration was 2.36Ϯ0.38% and 2.16Ϯ0.38% injected dose per gram of tissue (%ID/g), similar to 123 I-MIBG (2.14Ϯ0.30 and 2.19Ϯ0.27%ID/g). However, the heart to liver and lung uptake ratios were significantly higher for LMI1195 than for 123 I-MIBG. In rabbits, desipramine (1 mg/kg), a selective NET inhibitor, blocked LMI1195 heart uptake by 82%, which was more effective than 123 I-MIBG (53%), at 1 hour after dosing. Sympathetic denervation with 6-hydroxydopamine, a neurotoxin, resulted in a marked (79%) decrease in LMI1195 heart uptake. Cardiac PET imaging with LMI1195 in rats, rabbits, and nonhuman primates revealed clear myocardium with low radioactivity levels in the blood, lung, and liver. Imaging in rabbits pretreated with desipramine showed reduced heart radioactivity levels in a dose-dependent manner. Additionally, imaging in sympathetically denervated rabbits resulted in low cardiac image intensity with LMI1195 but normal perfusion images with flurpiridaz F 18, a PET myocardial perfusion imaging agent. In nonhuman primates pretreated with desipramine (0.5 mg/kg), imaging with LMI1195 showed a 66% decrease in myocardial uptake. In a rat model of heart failure, the LMI1195 cardiac uptake decreased as heart failure progressed. Conclusions-LMI1195 is a novel 18 F imaging agent retained in the heart through the NET and allowing evaluation of the cardiac sympathetic neuronal function by PET imaging. (Circ Cardiovasc Imaging. 2011;4:435-443.)
The goal of this research is the development of tumor imaging and radiotherapeutic agents based on targeting of the integrin alpha(v)beta(3) (vitronectin receptor). Macrocyclic chelator DOTA has been conjugated to peptidomimetic vitronectin receptor antagonist SH066 to give TA138. TA138 and (89)Y-TA138 retain antagonist properties and high affinity for integrin alpha(v)beta(3) (IC(50) = 12 and 18 nM, respectively), and good selectivity versus integrin alpha(IIb)beta(3) (IC(50) > 10,000 nM). TA138 forms stable complexes with (111)In and (90)Y in > 95% RCP. (111)In-TA138 demonstrates high tumor uptake in the c-neu Oncomouse (Charles River Laboratories [Charles River, Canada]) mammary adenocarcinoma model (9.39% ID/g at 2 hours PI) and low background activity. Blood clearance is rapid and excretion is renal. Tumors are visible as early as 0.5 hours PI. Radiotherapy studies in the c-neu Oncomouse model demonstrated a slowing of tumor growth at a dose of 15 mCi/m(2), and a regression of tumors at a dose of 90 mCi/m(2).
Metaplastic carcinomas of the breast (MCBs) are unusual neoplasms characterized by an admixture of glandular epithelial components, which frequently exhibit features of squamous differentiation, and mesenchymal malignant components. Regardless of the presence of myoepithelial features in MCB, no consensus concerning their putative histogenesis has yet been achieved. Recently, novel putative myoepithelial markers have been developed, including p63, maspin, and P-cadherin. We assessed the expression of these myoepithelial markers in MCBs and compared their expression with classic myoepithelial markers. Immunohistochemistry using the streptavidinbiotin-peroxidase complex technique with antibodies raised against p63, maspin, P-cadherin, actin (clones CGA7, 1A4 and HHF35), cytokeratin 14 (Ck14), and vimentin was performed on 16 MCBs (7 matrix-producing MCBs, 6 adenosquamous MCBs, and 3 MCBs with heterologous elements). In healthy breast lobules and ducts adjacent to the tumors, myoepithelial cells showed distinctive and consistent immunoreactivity for p63, maspin, P-cadherin, actin, S-100 protein, and Ck14. Matrix-producing MCBs were positive for maspin in all cases, for p63 in 4 of 7 cases, and for P-cadherin in 4 of 7 cases. Adenosquamous MCB showed immunoreactivity for p63, maspin, and P-cadherin in 5 of 6 cases. All novel myoepithelial markers and Ck14 decorated squamous cell islands. MCBs with heterologous elements were positive for p63 in 1 case, for maspin in all 3 cases, and for P-cadherin in 2 cases. All cases showed at least one of the novel myoepithelial markers. Eleven of 16 cases were positive for actin. Eleven of 14 cases reacted with Ck14, and all cases that stained for S-100 protein (9 of 9) and vimentin (13 of 13) were also positive. Based on our findings, the balance of probabilities favors that MCBs may have a basal or myoepithelial cell histogenesis and differentiation.
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