Altruism Heterogeneity and Quality Competition Among Healthcare Providers

New empirical evidence shows substantial heterogeneity in the altruism of healthcare providers. Spurred by this evidence, we build a spatial quality competition model with altruism heterogeneity. We find that more altruistic healthcare providers supply relatively higher quality levels and position themselves closer to the center. Whether the social planner prefers more or less horizontal differentiation is in general ambiguous and depends on the level of altruism. The more altruistic healthcare providers are, the more likely it is that the social planner prefers greater horizontal differentiation to offset costly quality competition.Neue empirische Evidenz für Leistungsanbieter im Gesundheitswesen zeigt, dass es erhebliche Heterogenität im Grad des Altruismus gibt. Auf Basis dieser neuen Evidenz entwickeln wir ein räumliches Wettbewerbsmodell, in dem Leistungsanbieter mittels Qualität konkurrieren und das für Heterogenität im Grad des Altruismus erlaubt. Wir finden, dass Leistungsanbieter, die durch einen relativ höheren Grad an Altruismus gekennzeichnet sind, auch höhere Qualitäten anbieten und sich zentraler allokieren (niedrigere horizontale Differenzierung). Ob aus der sozialen Perspektive mehr oder weniger horizontale Differenzierung bevorzugt wird, hängt von dem Grad des Altruismus ab. Je höher der Grad des Altruismus, desto wahrscheinlicher ist es, dass der Sozialplaner mehr horizontale Differenzierung bevorzugt, um den Qualitätswettbewerb einzuschränken

Proc. Natl. Acad. Sci. U. S. A.

Caspases form a family of proteinases required for the initiation and execution phases of apoptosis. Distinct proapoptotic stimuli lead to activation of the initiator caspases-8 and -9, which in turn activate the common executioner caspases-3 and -7 by proteolytic cleavage. Whereas crystal structures of several active caspases have been reported, no three-dimensional structure of an uncleaved caspase zymogen is available so far. We have determined the 2.9-Angstrom crystal structure of recombinant human C285A procaspase-7 and have elucidated the activation mechanism of caspases. The overall fold of the homodimeric procaspase-7 resembles that of the active tetrameric caspase-7. Each monomer is organized in two structured subdomains connected by partially flexible linkers, which asymmetrically occupy and block the central cavity, a typical feature of active caspases. This blockage is incompatible with a functional substrate binding site/active site. After proteolytic cleavage within the flexible linkers, the newly formed chain termini leave the cavity and fold outward to form stable structures. These conformational changes are associated with the formation of an intact active-site cleft. Therefore, this mechanism represents a formerly unknown type of proteinase zymogen activation

Risk and time preferences in individuals with lifestyle-related and non-lifestyle-related cardiovascular diseases: a pilot study

Objectives To (1) pilot a study of behavioural characterisation based on risk and time preferences in clinically well-characterised individuals, (2) assess the distribution of preferences in this population and (3) explore differences in preferences between individuals with ‘lifestyle-related’ (LS) and ‘non-lifestyle-related’ (NLS) cardiovascular diseases.Design Cross-sectional study with an economic online experiment to collect risk and time preferences, a detailed clinical characterisation and a sociodemographic and lifestyle survey. A definition of LS and NLS groups was developed.Setting Specialist outpatient clinics of the clinic for cardiology and pneumology of the University Hospital Düsseldorf and patients from a cardiology practice in Düsseldorf.Participants A total of 74 individuals with cardiovascular diseases.Outcomes Risk and time preferences.Results The implementation of the study process, including participant recruitment and data collection, ran smoothly. The medical checklist, the survey and the time preference instrument were well received. However, the conceptual understanding of the risk preference instrument resulted in inconsistent choices for many participants (47%). The remaining individuals were more risk averse (27%) than risk seeking (16%) and risk neutral (10%). Individuals in our sample were also more impatient (49%) than patient (42%). The participant classification showed that 65% belonged to the LS group, 19% to the NLS group and 16% could not be assigned (unclear allocation to lifestyle (ULS) group). Excluding the ULS group, we show that individuals in the LS group were more risk seeking, and unexpectedly, more patient than those in the NLS group.Conclusions The process of the pilot study and its results can be used as a basis for the design of the main study. The differences in risk and time preferences between the LS and NLS groups provide us with a novel hypothesis for unhealthy behaviours: individuals never give up a bad habit, they simply postpone the latter, which can be tested alongside other additional research questions

Structure

Riboflavin synthase catalyzes the disproportionation of 6,7- dimethyl-8-ribityllumazine affording riboflavin and 5-amino-6- ribitylamino-2,4(1H,3H)-pyrimidinedione. We have determined the structure of riboflavin synthase from Schizosaccharomyces pombe in complex with the substrate analog, 6-carboxyethyl-7-oxo-8- ribityllumazine at 2.1 Angstrom resolution. In contrast to the homotrimeric solution state of native riboflavin synthase, we found the enzyme to be monomeric in the crystal structure. Structural comparison of the riboflavin synthases of S. pombe and Escherichia coli suggests oligomer contact sites and delineates the catalytic site for dimerization of the substrate and subsequent fragmentation of the pentacyclic intermediate. The pentacyclic substrate dimer was modeled into the proposed active site, and its stereochemical features were determined. The model suggests that the substrate molecule at the C- terminal domain donates a four-carbon unit to the substrate molecule bound at the N-terminal domain of an adjacent subunit in the oligomer

Studies on the reaction mechanism of riboflavin synthase: X-ray crystal structure of a complex with 6-carboxyethyl-7-oxo-8- ribityllumazine

Riboflavin synthase catalyzes the disproportionation of 6,7- dimethyl-8-ribityllumazine affording riboflavin and 5-amino-6- ribitylamino-2,4(1H,3H)-pyrimidinedione. We have determined the structure of riboflavin synthase from Schizosaccharomyces pombe in complex with the substrate analog, 6-carboxyethyl-7-oxo-8- ribityllumazine at 2.1 Angstrom resolution. In contrast to the homotrimeric solution state of native riboflavin synthase, we found the enzyme to be monomeric in the crystal structure. Structural comparison of the riboflavin synthases of S. pombe and Escherichia coli suggests oligomer contact sites and delineates the catalytic site for dimerization of the substrate and subsequent fragmentation of the pentacyclic intermediate. The pentacyclic substrate dimer was modeled into the proposed active site, and its stereochemical features were determined. The model suggests that the substrate molecule at the C- terminal domain donates a four-carbon unit to the substrate molecule bound at the N-terminal domain of an adjacent subunit in the oligomer

Structural basis for the activation of human procaspase-7

Caspases form a family of proteinases required for the initiation and execution phases of apoptosis. Distinct proapoptotic stimuli lead to activation of the initiator caspases-8 and -9, which in turn activate the common executioner caspases-3 and -7 by proteolytic cleavage. Whereas crystal structures of several active caspases have been reported, no three-dimensional structure of an uncleaved caspase zymogen is available so far. We have determined the 2.9-Angstrom crystal structure of recombinant human C285A procaspase-7 and have elucidated the activation mechanism of caspases. The overall fold of the homodimeric procaspase-7 resembles that of the active tetrameric caspase-7. Each monomer is organized in two structured subdomains connected by partially flexible linkers, which asymmetrically occupy and block the central cavity, a typical feature of active caspases. This blockage is incompatible with a functional substrate binding site/active site. After proteolytic cleavage within the flexible linkers, the newly formed chain termini leave the cavity and fold outward to form stable structures. These conformational changes are associated with the formation of an intact active-site cleft. Therefore, this mechanism represents a formerly unknown type of proteinase zymogen activation