A. de Graaf

Radioimmunochemical determination of carbamoyl-phosphate synthase (ammonia) content of adult rat liver

1. Rabbit antiserum was raised against purified carbamoyl-phosphate synthase (ammonia) from rat liver. 2. The antiserum proved to be specific in double-diffusion test and reacted in an in situ immunohistochemical test on rat liver proteins fractionated on a sodium dodecyl sulphate polyacrylamide gel only in the region where carbamoyl-phosphate synthase (ammonia) migrated. 3. This antiserum was used for setting up a radioimmunochemical determination of carbamoyl-phosphate synthase (ammonia) in cetyltrimethylammonium bromide extracts of rat liver. To obtain reproducible results in this assay it was necessary to treat the unlabelled ligand with sodium dodecyl sulphate and dithiothreitol. This treatment led to a large increase in the percentage of labelled ligand displaceable by added unlabelled ligand. 4. Radioimmunochemical determination showed that adult rat liver (3-month old) contains 5.5 mg carbamoyl-phosphate synthase (ammonia) protein per gram wet weight.

The Differential Impact of Statistical and Narrative Evidence on Beliefs, Attitude, and Intention: A Meta-Analysis

Although “evidence” is often used as an important argument in persuasive health campaigns, it remains unclear what type of evidence has the strongest impact on particular outcome variables. We conducted a meta-analysis in which the effects of statistical and narrative evidence on beliefs, attitude, and intention were separately compared. Statistical evidence was found to have a stronger influence than narrative evidence on beliefs and attitude, whereas narrative evidence had a stronger influence on intention. We explain these findings in terms of the match between the specific characteristics of the two types of evidence and those of the outcome variables. Statistical evidence, beliefs, and attitude all relate primarily to cognitive responses, whereas both narrative evidence and intention relate more specifically to affective responses. We conclude that communication professionals developing health campaigns should match the type of evidence to the main communication objectives.

Control of the changes in rat-liver carbamoyl-phosphate synthase (ammonia) protein levels during ontogenesis: Evidence for a perinatal change in immunoreactivity of the enzyme

To analyze the changes in rat-liver carbamoyl-phosphate synthase (Cpase) protein levels during ontogenesis, these levels were determined by means of two independent methods, i.e. radioimmunoassay and densitometric assay. During normal development the changes in catalytic activity of Cpase are accompanied by equivalent changes in the quantities of enzyme protein. We have obtained evidence for the existence of a perinatal Cpase which is immunochemically different from adult Cpase as immunoreactivity of Cpase decreases in the perinatal period and remains constant thereafter.

A physiologically based in silico kinetic model predicting plasma cholesterol concentrations in humans

Increased plasma cholesterol concentration is associated with increased risk of cardiovascular disease. This study describes the development, validation, and analysis of a physiologically based kinetic (PBK) model for the prediction of plasma cholesterol concentrations in humans. This model was directly adapted from a PBK model for mice by incorporation of the reaction catalyzed by cholesterol ester transfer protein and contained 21 biochemical reactions and eight different cholesterol pools. The model was calibrated using published data for humans and validated by comparing model predictions on plasma cholesterol levels of subjects with 10 different genetic mutations (including familial hypercholesterolemia and Smith-Lemli-Opitz syndrome) with experimental data. Average model predictions on total cholesterol were accurate within 36% of the experimental data, which was within the experimental margin. Sensitivity analysis of the model indicated that the HDL cholesterol (HDL-C) concentration was mainly dependent on hepatic transport of cholesterol to HDL, cholesterol ester transfer from HDL to non-HDL, and hepatic uptake of cholesterol from non-HDL-C. Thus, the presented PBK model is a valid tool to predict the effect of genetic mutations on cholesterol concentrations, opening the way for future studies on the effect of different drugs on cholesterol levels in various subpopulations in silico.

Reduction in phosphoenolpyruvate carboxykinase in rat liver parenchymal cells following experimentally induced cholestasis

SummaryThe effect of experimentally induced cholestasis on the amount of phosphoenolpyruvate carboxykinase (PEPCK) was studied immunohistochemically in rat liver parenchyma. In control liver, the enzyme was mainly localized periportally and, although the enzyme content was much reduced, this distribution pattern was maintained up to 2 weeks after ligation of the common bile duct. At 4 and 8 weeks after ligation the enzyme content in parenchymal cells remained low, but became distributed homogeneously throughout the liver parenchyma. This suggests that after bile duct ligation, gluconeogenesis from lactate is impaired. This may well be the cause of the adaptive changes to enhance the glycogenolytic capacity of parenchymal cells to maintain as far as possible a constant blood glucose level.

Alcohol Makes Others Dislike You: Reducing the Positivity of Teens’ Beliefs and Attitudes Toward Alcohol Use

This study tests the effects of the portrayal of negative consequences of alcohol use on beliefs and attitudes toward alcohol consumption. In a between-subjects experiment (N = 108), participants were randomly assigned to watch one of three conditions. One group of participants watched a version of an edited episode of the reality program Jersey Shore in which alcohol use had negative consequences, another group watched a version of the episode in which alcohol use had more positive consequences, and a control group was not exposed to any program. Results showed that participants who saw the version with negative consequences had more negative beliefs about alcohol and more negative attitudes toward beer than participants who saw the more positive consequences and participants in the control condition. This indicates that the portrayal of negative consequences can have positive outcomes for viewers’ health beliefs and attitudes, reducing their positivity toward alcohol use.This study tests the effects of the portrayal of negative consequences of alcohol use on beliefs and attitudes toward alcohol consumption. In a between-subjects experiment (N = 108), participants were randomly assigned to watch one of three conditions. One group of participants watched a version of an edited episode of the reality program Jersey Shore in which alcohol use had negative consequences, another group watched a version of the episode in which alcohol use had more positive consequences, and a control group was not exposed to any program. Results showed that participants who saw the version with negative consequences had more negative beliefs about alcohol and more negative attitudes toward beer than participants who saw the more positive consequences and participants in the control condition. This indicates that the portrayal of negative consequences can have positive outcomes for viewers’ health beliefs and attitudes, reducing their positivity toward alcohol use.

Limitations in the applicability of the complement‐fixation test for the estimation of specificity of histone antisera

Among the different histone classes, the ~y~ne-~~h histone class reveals the greatest in&a-specitic variability [ 1,2]. This class contains a number of histone Hl variants. A remarkable lysine-rich histone variant is histone H5, that has been described as erythrocyte specific in a variety of species [3--s] among which ~e~fo~~s f6]. In order to determine the developmental stage in which H5 appears and to andlyse in detail in which cells this occurs, we set up an indirect immunofluorescent technique on tissue sections from several developments stages, using antibodies elicited against HI and HS from ~e~o~~s, respectively. These antibodies were specific as determined by a complement fixation assay and by an in situ immune peroxidase assay with histones fractionated on a polyacrylamide get as shown before f6]_ Unexpectedly, we found in tissue sections from Xenopus Eaevis tadpoles, that anti-H5 serum reacted, not only with erythrocyte nuclei, but also with nuclei from other cell types, that are not considered to differentiate into erythrocytes (e.g. myotomes) [7 J. This observation could be of potential importance for considerations on developments mechanisms of tissue differentiation. However, a trivial explanation that would invalidate this finding would be a crossreaction of this anti-H5 serum with histone Hl, because of the expected high degree of homology between Hi and H.5 (cf. [S]). Thus, in spite of the observed specificity in the

Effects of issue involvement and framing of a responsible drinking message on attitudes, intentions, and behavior

To decrease the prevalence and the amount of alcohol consumption among students, health messages advocating responsible alcohol behavior can be used. However, it is unclear whether responsible drinking messages are most effective when they use a gain frame, presenting the advantages of responsible drinking, or a loss frame, presenting the disadvantages of irresponsible drinking. This study tests the effects of framing and the moderating role of involvement with the issue of responsible drinking. A three-wave, between-subjects, experimental study was conducted, in which participants (N = 90) were exposed to either a gain- or loss-framed message about responsible drinking behavior at Wave 2. At all three waves, attitudes, intentions and behavior toward responsible drinking were measured. Results showed that for participants with low issue- involvement, a gain frame led to more positive attitudes and intentions toward responsible alcohol use, whereas a loss frame did not have any effects for them. For participants with high issue involvement, a loss frame led to more positive attitudes and intentions toward responsible alcohol use, whereas a gain frame did not have an effect on attitude and only a delayed effect on intention. However, there were no effects of frame and issue involvement on adhering to the guideline of responsible alcohol use and average drinking behavior.

The onset of type 2 diabetes: Proposal for a multi-scale model

Background Type 2 diabetes mellitus (T2D) is a common age-related disease, and is a major health concern, particularly in developed countries where the population is aging, including Europe. The multi-scale immune system simulator for the onset of type 2 diabetes (MISSION-T2D) is a European Union-funded project that aims to develop and validate an integrated, multilevel, and patient-specific model, incorporating genetic, metabolic, and nutritional data for the simulation and prediction of metabolic and inflammatory processes in the onset and progression of T2D. The project will ultimately provide a tool for diagnosis and clinical decision making that can estimate the risk of developing T2D and predict its progression in response to possible therapies. Recent data showed that T2D and its complications, specifically in the heart, kidney, retina, and feet, should be considered a systemic disease that is sustained by a pervasive, metabolically-driven state of inflammation. Accordingly, there is an urgent need (1) to understand the complex mechanisms underpinning the onset of this disease, and (2) to identify early patient-specific diagnostic parameters and related inflammatory indicators. Objective We aim to accomplish this mission by setting up a multi-scale model to study the systemic interactions of the biological mechanisms involved in response to a variety of nutritional and metabolic stimuli and stressors. Methods Specifically, we will be studying the biological mechanisms of immunological/inflammatory processes, energy intake/expenditure ratio, and cell cycle rate. The overall architecture of the model will exploit an already established immune system simulator as well as several discrete and continuous mathematical methods for modeling of the processes critically involved in the onset and progression of T2D. We aim to validate the predictions of our models using actual biological and clinical data. Results This study was initiated in March 2013 and is expected to be completed by February 2016. Conclusions MISSION-T2D aims to pave the way for translating validated multilevel immune-metabolic models into the clinical setting of T2D. This approach will eventually generate predictive biomarkers for this disease from the integration of clinical data with metabolic, nutritional, immune/inflammatory, genetic, and gut microbiota profiles. Eventually, it should prove possible to translate these into cost-effective and mobile-based diagnostic tools.

Systematic construction of a conceptual minimal model of plasma cholesterol levels based on knockout mouse phenotypes

Elevated plasma cholesterol, a well-known risk factor for cardiovascular diseases, is the result of the activity of many genes and their encoded proteins in a complex physiological network. We aim to develop a minimal kinetic computational model for predicting plasma cholesterol levels. To define the scope of this model, it is essential to discriminate between important and less important processes influencing plasma cholesterol levels. To this end, we performed a systematic review of mouse knockout strains and used the resulting dataset, named KOMDIP, for the identification of key genes that determine plasma cholesterol levels. Based on the described phenotype of mouse knockout models, 36 of the 120 evaluated genes were marked as key genes that have a pronounced effect on the plasma cholesterol concentration. The key genes include well-known genes, e.g., Apoe and Ldlr, as well as genes hardly linked to cholesterol metabolism so far, e.g., Plagl2 and Slc37a4. Based on the catalytic function of the genes, a minimal conceptual model was defined. A comparison with nine conceptual models from literature revealed that each of the individual published models is less complete than our model. Concluding, we have developed a conceptual model that can be used to develop a physiologically based kinetic model to quantitatively predict plasma cholesterol levels.