Age-related changes in the metabolism of cholesterol in rat liver microsomes

The effects of aging on the hepatic metabolism of cholesterol were studied in 1-, 6- and 24-month-old male Sprague-Dawley rats. Microsomal 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity, which regulates cholesterol biosynthesis, decreased from 835±144 (SEM) pmol/min/mg protein in the youngest group to 219±34 and 205±53 pmol/min/mg protein (p<0.001) in the 6- and 24-month-old groups, respectively. Cholesterol 7α-hydroxylase activity, which governs bile acid synthesis, was gradually reduced from 70±14 pmol/min/mg protein in the 1-month-old group to 32±7 and 16±3 pmol/min/mg protein (p<0.05) in the 6- and 24-month-old groups, respectively. Acyl coenzyme A:cholesterol acyltransferase activity, which catalyzes the esterification of cholesterol, averaged 431±47 and 452 ±48 pmol/min/mg protein in the 1- and 6-month-old groups, respectively, and was increased to 585±55 pmol/min/mg protein (p<0.05) in the 24-month-old group. The level of total cholesterol showed an age-related increase from 1.56±0.16 mg/g liver in the 1-month-old group to 1.70±0.15 and 2.20±0.19 mg/g liver (p<0.05) in the 6- and 24-month-old groups, respectively. The increase was mainly caused by an accumulation of esterified cholesterol. We conclude that a marked decrease in HMG-CoA reductase occurs between 1 and 6 months of age; thereafter the enzyme activity stays unchanged. The activity of cholesterol 7α-hydroxylase decreases progressively and drastically with age, whereas the capacity for esterifying cholesterol increases slightly. We speculate that the reduced conversion of cholesterol to bile acids may be one explanation of the age-related increase of plasma cholesterol seen in rats.     

Experimental zones: two cases of exploring frames of participation in a dialogic museum

Abstract

A matter of concern for dialogic institutions such as museums is the struggle to find appropriate ways of integrating social media and digital technologies into dialogues with visitors. This paper addresses how co-creation and experimental methods may be applied in a situated, natural environment, exploring how these technologies may be shaped to support museum visitor relations. The concept ‘experimental zone’ is suggested as a format for a collaborative design space where digital media-based dialogues are explored in line with professional practices. This concept is discussed in relation to two design experiments undertaken in collaboration with the Norwegian Museum of Science and Technology.     

Matters of becoming,experimental zones for making museums public with social media

Making things public challenges existing matters of concern and, in design, may also be about changing them. This paper advances the concept of translation from early ANT literature and explores it in order to support co-designing for making things public. We elaborate on how translations may be understood as moves and transformations of practices and objects that require both time and learning. We discuss how translations may include the emerging, situated, fluid, enacted, experiential and the material, and suggest co-design to rethink translation as a temporal process of learning and ‘becoming’. Our aim is to demonstrate a mutual theoretical influence between ANT and co-design. Our conceptual reflection is based on a museum design case where museum staff and the authors explore new communicational modes of social media. The project established a longitudinal ‘experimental zone’ as space and time for design in the everyday practice of the museum. The paper reflects upon the value of ANT as a framework for rethinking the design–use divide using concepts of learning and translations to bring awareness of co-design as temporal, fluid and emerging processes of becoming.     

Studying creativity training programs: A methodological analysis

Throughout decades of creativity research, a range of creativity training programs have been developed, tested, and analyzed. In 2004 Scott and colleagues published a meta‐analysis of all creativity training programs to date, and the review presented here sat out to identify and analyze studies published since the seminal 2004 review. Focusing on quantitative studies of creativity training programs for adults, our systematic review resulted in 22 publications. All studies were analyzed, but comparing the reported effectiveness of training across studies proved difficult due to methodological inconsistencies, variations in reporting of results as well as types of measures used. Thus a consensus for future studies is called for to answer the question: Which elements make one creativity training program more effective than another? This is a question of equal relevance to academia and industry, as creativity training is a tool that can contribute to enhancement of organizational creativity and subsequently innovation. However, to answer the question, future studies of creativity training programs need to be carefully designed to contribute to a more transparent landscape. Thus this paper proposes a methodological research standard consisting of three criteria, to which researchers can look when designing future studies of the effectiveness of creativity training.     

Thematic Apperception Test: Some evidence bearing on the "hero assumption."

2 experiments are presented which test the assumption that there is customarily a single figure in TAT stories which is particularly revealing of the Ss own attributes. In a group of 30 female Ss it was demonstrated that hero figures were more often identified as similar to self or else denied as similar. Following a frustration experience aggressive acts carried out by heroes against others and against the self and also aggressive acts carried out by others against the hero all increased. These findings were regarded as evidence for the hero assumption. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of pregnenolone-16α-carbonitrile on the metabolism of cholesterol in rat liver microsomes

The effects of pregnenolone-16α-carbonitrile (PCN) on hepatic metabolism of cholesterol were studied in rat liver microsomes in order to clarify the underlying mechanisms of the PCN-induced biliary hypersecretion of cholesterol. Male Sprague-Dawley rats were fed a diet supplemented with 0.05% of PCN for one week. The microsomal activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase, regulating cholesterol biosynthesis, decreased from 577 ± 46 (SEM) to 367 ± 38 pmol/min/mg protein compared to the controls. Cholesterol 7 α-hydroxylase activity, governing bile acid synthesis, was 9.0 ± 1.1 pmol/min/mg protein in the treated group and 34.8 ± 7.4 pmol/min/mg protein in the controls, a reduction of 74% (P<0.01). The acyl CoA:cholesterol acyltransferase (ACAT) activity, catalyzing the esterification of cholesterol, remained unchanged, as did the levels of total and free cholesterol in liver homogenates and microsomes. The results of this study provide evidence that the increase in biliary cholesterol secretion during PCN treatment is not caused by a change in ACAT activity, but can be explained by a decreased catabolism of cholesterol to bile acids.     

Designing for Young Visitors’ Co-composition of Doubts in Cultural Historical Exhibitions

This paper reports from a design experiment that investigated how social media may introduce new types of participation in museum exhibitions. We used the perspectives of assemblage and co-composition as frameworks to rethink participation in museums. The design experiment's aim was to give visitors an experience of the uncertainties and doubts of historical knowledge creation by inviting visitors to participate in solving dilemmas and filling gaps in the reconstruction of a Viking boat. We introduced three design concepts in our lab-based exhibition experiment—collecting, reflecting and sharing—to capture the social interactions and collaborative media production that enacts the exhibition assembly. We conclude that visitors’ reflections may evolve through participatory activities of collecting and sharing, and social media may open possibilities for new types of interpretation and learning activities in museum exhibitions.