286 research outputs found
The influence of shc proteins and aging on whole body energy expenditure and substrate utilization in mice.
While it has been proposed that Shc family of adaptor proteins may influence aging by regulating insulin signaling and energy metabolism, the overall impact of Shc proteins on whole body energy metabolism has yet to be elucidated. Thus, the purpose of this study was to determine the influence of Shc proteins and aging on whole body energy metabolism in a mouse model under ambient conditions (22°C) and acute cold exposure (12°C for 24 hours). Using indirect respiration calorimetry, we investigated the impact of Shc proteins and aging on EE and substrate utilization (RQ) in p66 Shc-/- (ShcKO) and wild-type (WT) mice. Calorimetry measurements were completed in 3, 15, and 27 mo mice at 22°C and 12°C. At both temperatures and when analyzed across all age groups, ShcKO mice demonstrated lower 24 h total EE values than that of WT mice when EE data was expressed as either kJ per mouse, or adjusted by body weight or crude organ mass (ORGAN) (P≤0.01 for all). The ShcKO mice also had higher (P<0.05) fed state RQ values than WT animals at 22°C, consistent with an increase in glucose utilization. However, Shc proteins did not influence age-related changes in energy expenditure or RQ. Age had a significant impact on EE at 22°C, regardless of how EE data was expressed (P<0.05), demonstrating a pattern of increase in EE from age 3 to 15 mo, followed by a decrease in EE at 27 mo. These results indicate a decline in whole body EE with advanced age in mice, independent of changes in body weight (BW) or fat free mass (FFM). The results of this study indicate that both Shc proteins and aging should be considered as factors that influence energy expenditure in mice
The influence of shc proteins on the whole body energetic response to calorie restriction initiated in 3-month-old mice.
There is increasing evidence that Shc proteins play a role in energy metabolism, and we have previously reported that knockdown of Shc proteins influences the energetic response to acute (3 days) calorie restriction (CR) in 18-month-old mice. Whether Shc proteins play a role in the metabolic response to CR in younger mice has yet to be elucidated. Hence, we sought to determine the impact of 3 days and longer term (2 months) CR on energy expenditure (EE) and respiratory quotient (RQ) in 3 month-old Shc knockout (ShcKO) and wild-type (WT) mice. ShcKO mice decreased (P < 0.001) EE normalized for body weight (EEBW) by 3 days of CR, while no such change was observed in WT animals. However, both ShcKO and WT mice decreased (P < 0.001) EEBW at 2 months of CR and there were no differences in body weight between the ShcKO and WT mice at either 3 days or 2 months of CR. Consistent with increased fatty acid oxidation, only ShcKO mice maintained decreased (P < 0.001) 24 h RQ through 2 months of CR, suggesting that they were able to maintain increased fatty acid oxidation for a longer period of time than WT mice. These results indicate that Shc proteins may contribute to some of the acute energetic responses to CR
‘This is a problem (.)’ : discursive construction of the organisational ‘problems’ in a multinational corporate workplace
Problem solving in the workplace is a high stakes activity that has important implications for organisations and individuals. Although problem-solving has attracted a lot of attention, there is little research on the interactional aspects of problem-solving processes. There are also few attempts to make interactional research relevant to business studies on organisational problems. In this thesis, I adopt a discursive approach and understand problems as locally produced in and through interaction. I draw on one case study and discuss data collected in one multinational company. Through interviews and interactional data, the thesis investigates how organisational ‘problems’ are constructed (and occasionally solved). The discussion focuses on the discursive resources employees draw upon in formulating problems and their professional roles and responsibilities negotiated in problem solving meetings. Special attention is paid to the meeting event and the HQ-subsidiary context in relation to the ways in which issues are negotiated and ratified as ‘problems’.
The findings show that in interviews, language and culture, as abstract concepts, constitute key resources for the construction of organisational problems. In participants’ talk about language and culture, the individuals’ ideologies are enacted, and the abstract concepts become critical means for positioning (them)selves and others in the organisational setting. In problem-solving meetings, I focus on interactional activities which emerge in the timeframe of the meeting event. The patterns of these activities are not linear but shaped by the participants’ interactional and institutional positioning through which their professional roles are enacted. I argue that the processes of constructing organisational problems are contingent on the ability of individuals to access and challenge dominant institutional and professional discourses and ideologies. Based on the analysis, I propose a model that visualises interactional moves that constitute problem-solving activities in the meeting event. I conclude the discussion of the data by also proposing a model on the HQ-subsidiary relationships as emergent in the problem-solving interaction
Share of Wallet in Loyalty Research: Issues and a Methodology to Address Them
In a competitive market environment, share of wallet is a key measure for customer relationship management. Share of wallet analysis enables the firm to be more proactive in their ability to target customers to increase additional spending. Although share of wallet is important as a measure of customer loyalty, there is a dearth of research which focuses on share of wallet per se. In this paper, we briefly review the share of wallet literature in the context of its value to loyalty researchers. We illustrate some issues regarding share of wallet in identifying loyalty and then discuss the development of a methodology to alleviate the issues by introducing an adjusted share of wallet approach, “Share of Wallet Index” (SOWI). SOWI is calculated by multiplying by the square root of the percent that each customer is above and below the median spend in the category times the raw share of wallet measure.
The SOWI approach offers a useful tradeoff between modeling total dollars and modeling raw share of wallet by taking into account both category spend and category share. It also contributes to the literature on customer relationship management and loyalty and advances the empirical analysis on the customer loyalty behavior. This research provides several managerial implications. First, this share of wallet index may help firms to identify additional revenue opportunities when more effort is used with specific customers. Second, firms can understand their relative competitive positions in the market place. We discuss limitations and future research opportunities
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Dysregulated Choline, Methionine, and Aromatic Amino Acid Metabolism in Patients with Wilson Disease: Exploratory Metabolomic Profiling and Implications for Hepatic and Neurologic Phenotypes.
Wilson disease (WD) is a genetic copper overload condition characterized by hepatic and neuropsychiatric symptoms with a not well-understood pathogenesis. Dysregulated methionine cycle is reported in animal models of WD, though not verified in humans. Choline is essential for lipid and methionine metabolism. Defects in neurotransmitters as acetylcholine, and biogenic amines are reported in WD; however, less is known about their circulating precursors. We aimed to study choline, methionine, aromatic amino acids, and phospholipids in serum of WD subjects. Hydrophilic interaction chromatography-quadrupole time-of-flight mass spectrometry was employed to profile serum of WD subjects categorized as hepatic, neurologic, and pre-clinical. Hepatic transcript levels of genes related to choline and methionine metabolism were verified in the Jackson Laboratory toxic milk mouse model of WD (tx-j). Compared to healthy subjects, choline, methionine, ornithine, proline, phenylalanine, tyrosine, and histidine were significantly elevated in WD, with marked alterations in phosphatidylcholines and reductions in sphingosine-1-phosphate, sphingomyelins, and acylcarnitines. In tx-j mice, choline, methionine, and phosphatidylcholine were similarly dysregulated. Elevated choline is a hallmark dysregulation in WD interconnected with alterations in methionine and phospholipid metabolism, which are relevant to hepatic steatosis. The elevated phenylalanine, tyrosine, and histidine carry implications for neurologic manifestations and are worth further investigation
Topical clobetasol for the treatment of toxic epidermal necrolysis: study protocol for a randomized controlled trial.
BackgroundToxic epidermal necrolysis (TEN) is a rare systemic allergic drug eruption with high patient mortality. Currently, no established treatments have been shown to be effective for TEN beyond supportive care. Prior studies of systemic corticosteroids have yielded conflicting data, with some showing a possible benefit and others reporting in increased mortality. However, topical steroids have shown promise for treatment of ocular sequelae of TEN, such as scarring and vision loss. We have designed a randomized controlled trial to evaluate topical clobetasol for treatment of the epidermal manifestations of TEN. In addition, we propose genetic studies to characterize the TEN transcriptome and alterations in cutaneous gene expression that might occur following topical steroid treatment.Methods/designThis split-body randomized, double-blind, placebo-controlled Phase IIa proof-of-concept trial will evaluate the safety and efficacy of once-daily topical clobetasol applied to the skin of patients with TEN. This multicenter trial will recruit a total of 15 patients between the ages of 12 and 85 from the University of California Davis Medical Center and Shriners Hospital for Children inpatient burn units. Designated treatment areas on opposite sides of the body will be treated with blinded clobetasol 0.05% ointment or control petrolatum ointment daily for 14 days. On day 3 of therapy, a biopsy will be taken from the treated area for genetic studies. The primary study aims will be to establish the safety of topical clobetasol treatment and determine the time to cessation of skin detachment for the control and clobetasol-treated areas. Secondary endpoints will evaluate efficacy using parameters such as time to 90% re-epithelialization and percentage of affected skin at 0, 3, 6, 9, 12 and 15 days. Genomic DNA and RNA will be obtained from biopsy samples, to characterize the TEN transcriptome and identify changes in gene expression after topical steroid treatment.DiscussionTopical steroids have shown promise for treating ocular complications of TEN, but to date have not been evaluated for cutaneous manifestations of the disease. This trial will investigate clinical and molecular outcomes of topical clobetasol application and hopefully provide insight into the disease pathophysiology.Trial registrationClinicalTrials.gov NCT02319616. https://clinicaltrials.gov/ct2/show/NCT02351037
Mice with low levels of Shc proteins display reduced glycolytic and increased gluconeogenic activities in liver.
Shc proteins play a role in energy metabolism through interaction with the insulin receptor. The aim of this study was to determine whether Shc proteins influence liver glycolysis and gluconeogenesis under both fed and fasted states. Decreased glycolytic and increased gluconeogenic and transamination enzyme activities were observed in ShcKO versus WT mice. Levels of key regulatory metabolites, such as fructose-2,6-bisphosphate, matched the activity of metabolic pathways. Protein levels of glycolytic and gluconeogenic enzymes were not different. pAMPK protein levels increased with fasting and were higher in ShcKO versus WT mice. Therefore, Shc proteins play a role in shifting the metabolism from glucose oxidation to gluconeogenesis and lipid catabolism and should be considered as regulators of fuel selection. Fuel selection and utilization could play a critical role in healthy aging. Characterization of metabolic events in ShcKO mice would help to elucidate how metabolism is influenced by these proteins
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