Health and (other) Asset Holdings

The empirical literature on the asset allocation and medical expenditures of U.S. households consistently shows that risky portfolio shares are increasing in both wealth and health whereas health investment shares are decreasing in these same variables. Despite this evidence, most of the existing models treat financial and health-related choices separately. This paper bridges this gap by proposing a tractable framework for the joint determination of optimal consumption, portfolio and health investments. We solve for the optimal rules in closed form and show that the model can theoretically reproduce the empirical facts. Capitalizing on this closed-form solution, we perform a structural estimation of the model on HRS data. Our parameter estimates are reasonable and confirm the relevance of all the main characteristics of the model.

Frequent users of emergency departments present very high prevalence of mental health and substance use disorders, which are largery underdiagnosed by clinicians.

Background: The objective of this study was to determine if mental health and substance use diagnoses were equally detected in frequent users (FUs) compared to infrequent users (IUs) of emergency departments (EDs). Methods: In a sample of 399 adult patients (>= 18 years old) admitted to a teaching hospital ED, we compared the mental health and substance use disorders diagnoses established clinically and consigned in the medical files by the ED physicians to data obtained in face-to-face research interviews using the Primary Care Evaluation of Mental Disorders (PRIME-MD) and the Alcohol, Smoking and Involvement Screening Test (ASSIST). Between November 2009 and June 2010, 226 FUs (>4 visits within a year) who attended the ED were included, and 173 IUs (<= 4 visits within a year) were randomly selected from a pool of identified patients to comprise the comparison group. Results: For mental health disorders identified by the PRIME-MD, FUs were more likely than IUs to have an anxiety (34 vs. 16%, Chi2(1) = 16.74, p <0.001), depressive (47 vs. 25%, Chi2(1) = 19.11, p <0.001) or posttraumatic stress (PTSD) disorder (11 vs. 5%, Chi2(1) = 4.87, p = 0.027). Only 3/76 FUs (4%) with an anxiety disorder, 16/104 FUs (15%) with a depressive disorder and none of the 24 FUs with PTSD were detected by the ED medical staff. None of the 27 IUs with an anxiety disorder, 6/43 IUs (14%) with a depressive disorder and none of the 8 IUs with PTSD were detected. For substance use disorders identified by the ASSIST, FUs were more at risk than IUs for alcohol (24 vs. 7%, Chi2(1) = 21.12, p <0.001) and drug abuse/dependence (36 vs. 25%, Chi2(1) = 5.52, p = 0.019). Of the FUs, 14/54 (26%) using alcohol and 8/81 (10%) using drugs were detected by the ED physicians. Of the IUs, 5/12 (41%) using alcohol and none of the 43 using drugs were detected. Overall, there was no significant difference in the rate of detection of mental health and substance use disorders between FUs and IUs (Fisher's Exact Test: anxiety, p = 0.567; depression, p = 1.000; PTSD, p = 1.000; alcohol, p = 0.517; and drugs, p = 0.053). Conclusions: While the prevalence of mental health and substance use disorders was higher among FUs, the rates of detection were not significantly different for FUs vs. IUs. However, it may be that drug disorders among FUs were more likely to be detected.

Roles of PPARs in health and disease.

In developed societies, chronic diseases such as diabetes, obesity, atherosclerosis and cancer are responsible for most deaths. These ailments have complex causes involving genetic, environmental and nutritional factors. There is evidence that a group of closely related nuclear receptors, called peroxisome proliferator-activated receptors (PPARs), may be involved in these diseases. This, together with the fact that PPAR activity can be modulated by drugs such as thiazolidinediones and fibrates, has instigated a huge research effort into PPARs. Here we present the latest developments in the PPAR field, with particular emphasis on the physiological function of PPARs during various nutritional states, and the possible role of PPARs in several chronic diseases.

Comparison of organ doses and image quality between CT and flat panel XperCT scans in wrist and inner ear examinations.

The aim of this study was to evaluate and compare organ doses delivered to patients in wrist and petrous bone examinations using a multislice spiral computed tomography (CT) and a C-arm cone-beam CT equipped with a flat-panel detector (XperCT). For this purpose, doses to the target organ, i.e. wrist or petrous bone, together with those to the most radiosensitive nearby organs, i.e. thyroid and eye lens, were measured and compared. Furthermore, image quality was compared for both imaging systems and different acquisition modes using a Catphan phantom. Results show that both systems guarantee adequate accuracy for diagnostic purposes for wrist and petrous bone examinations. Compared with the CT scanner, the XperCT system slightly reduces the dose to target organs and shortens the overall duration of the wrist examination. In addition, using the XperCT enables a reduction of the dose to the eye lens during head scans (skull base and ear examinations).

Treatment of acute uncomplicated falciparum malaria with artemether-lumefantrine in nonimmune populations: a safety, efficacy, and pharmacokinetic study.

The efficacy and safety of artemether-lumefantrine for the treatment of malaria in nonimmune populations are not well defined. In this study, 165 nonimmune patients from Europe and non-malarious areas of Colombia with acute, uncomplicated falciparum malaria or mixed infection including P. falciparum were treated with the six-dose regimen of artemether-lumefantrine. The parasitologic cure rate at 28 days was 96.0% for the per protocol population (119/124 patients). Median times to parasite clearance and fever clearance were 41.5 and 36.8 hours, respectively. No patient had gametocytes after Day 7. Treatment was well tolerated; most adverse events were mild to moderate and seemed to be related to malaria. There were few serious adverse events, none of which were considered to be drug-related. No significant effects on ECG or laboratory parameters were observed. In conclusion, the six-dose regimen of artemether-lumefantrine was effective and well tolerated in the treatment of acute uncomplicated falciparum malaria in nonimmune patients.

Health and (Other) Asset Holdings

Despite clear evidence of correlations between financial and medical statuses and decisions, most models treat financial and health-related choices separately. This article bridges this gap by proposing a tractable dynamic framework for the joint determination of optimal consumption, portfolio holdings, health investment, and health insurance. We solve for the optimal rules in closed form and capitalize on this tractability to gain a better understanding of the conditions under which separation between financial and health-related decisions is sensible, and of the pathways through which wealth and health determine allocations, welfare and other variables of interest such as expected longevity or the value of health. Furthermore we show that the model is consistent with the observed patterns of individual allocations and provide realistic estimates of the parameters that confirm the relevance of all the main characteristics of the model.

State-of-the-art of 3D cultures (organs-on-a-chip) in safety testing and pathophysiology.

Integrated approaches using different in vitro methods in combination with bioinformatics can (i) increase the success rate and speed of drug development; (ii) improve the accuracy of toxicological risk assessment; and (iii) increase our understanding of disease. Three-dimensional (3D) cell culture models are important building blocks of this strategy which has emerged during the last years. The majority of these models are organotypic, i.e., they aim to reproduce major functions of an organ or organ system. This implies in many cases that more than one cell type forms the 3D structure, and often matrix elements play an important role. This review summarizes the state of the art concerning commonalities of the different models. For instance, the theory of mass transport/metabolite exchange in 3D systems and the special analytical requirements for test endpoints in organotypic cultures are discussed in detail. In the next part, 3D model systems for selected organs--liver, lung, skin, brain--are presented and characterized in dedicated chapters. Also, 3D approaches to the modeling of tumors are presented and discussed. All chapters give a historical background, illustrate the large variety of approaches, and highlight up- and downsides as well as specific requirements. Moreover, they refer to the application in disease modeling, drug discovery and safety assessment. Finally, consensus recommendations indicate a roadmap for the successful implementation of 3D models in routine screening. It is expected that the use of such models will accelerate progress by reducing error rates and wrong predictions from compound testing.

Objective assessment of image quality in conventional and digital mammography taking into account dynamic range.

The goal of this work is to develop a method to objectively compare the performance of a digital and a screen-film mammography system in terms of image quality. The method takes into account the dynamic range of the image detector, the detection of high and low contrast structures, the visualisation of the images and the observer response. A test object, designed to represent a compressed breast, was constructed from various tissue equivalent materials ranging from purely adipose to purely glandular composition. Different areas within the test object permitted the evaluation of low and high contrast detection, spatial resolution and image noise. All the images (digital and conventional) were captured using a CCD camera to include the visualisation process in the image quality assessment. A mathematical model observer (non-prewhitening matched filter), that calculates the detectability of high and low contrast structures using spatial resolution, noise and contrast, was used to compare the two technologies. Our results show that for a given patient dose, the detection of high and low contrast structures is significantly better for the digital system than for the conventional screen-film system studied. The method of using a test object with a large tissue composition range combined with a camera to compare conventional and digital imaging modalities can be applied to other radiological imaging techniques. In particular it could be used to optimise the process of radiographic reading of soft copy images.

Exposure to bioaerosols, respiratory health and lung-specific proteins: a prospective study in garbage and wastewater workers.

Objectives To prospectively assess respiratory health in wastewater workers and garbage collectors over 5 years. Methods Exposure, respiratory symptoms and conditions, spirometry and lung-specific proteins were assessed yearly in a cohort of 304 controls, 247 wastewater workers and 52 garbage collectors. Results were analysed with random coefficient models and linear regression taking into account several potential confounders. Results Symptoms, spirometry and lung-specific proteins were not affected by occupational exposure. Conclusions In this population no effects of occupational exposure to bioaerosols were found, probably because of good working conditions.

Lymphoid stroma in health and disease

Summary Secondary lymphoid organs (SLOB), such as lymph nodes and spleen, are the sites where primary immune responses are initiated. T lymphocytes patrol through the blood and SLOs on the search for pathogens which are presented to them as antigens by dendritic cells. Stromal cells in the Tzone - so called T zone fibroblastic reticular cells (TRCs) -are critical in organizing the migration of T cells and dendritic cells by producing the chemoattractants CCL19 and CCL21 and by forming a network which T cells use as a guidance system. They also form a system of small channels or conduits that allow rapid transport of small antigen molecules or cytokines from the subcapsular sinus to high endothelial venules. The phenotype and function of TRCs have otherwise remained largely unknown. We found a critical role for lymph node access in CD4+ and CD8+ T cell homeostasis and identified TRCs within these organs as the major source of interleukin-7 (IL-7). IL-7 is an essential survival factor for naïve T lymphocytes of which the cellular source in the periphery had been poorly defined. In vitro, TRC were able to prevent the death of naïve T but not of B lymphocytes by secreting IL-7 and the CCR7 ligand CCL 19. Using gene-targeted mice, we show anon-redundant function of CCL19 in T cell homeostasis. The data suggest that TRCs regulate T cell numbers by providing a limited reservoir of survival factors for which T cells have to compete. They help to maintain a diverse T cell repertoire granting full immunocompetence. To determine whether TRCs also play a role in pathology, we characterized so-called tertiary lymphoid organs (TLOs) that often develop at sites of chronic inflammation. We show that TLOs resemble lymph nodes or Peyer's patches not only with regard to lymphoid cells. TLOs formed extensive TRC networks and a functional conduit system in all three marine inflammation models tested. In one model we dissected the cells and signals leading to the formation of these structures. We showed that they critically depend on the presence of lymphotoxin and lymphoid tissue inducer cells. TRCs in TLOs also produce CCL19, GCL21 and possibly IL-7 which are all involved in the development of TLOs. Stromal cells therefore play a central role in the onset and perpetuation of chronic inflammatory diseases and could be an interesting target for therapy. Résumé Le système immunitaire est la défense de notre corps contre toutes sortes d'infections et de tumeurs. II est constitué de différentes populations de lymphocytes qui patrouillent constamment le corps à la recherche de pathogène. Parmi eux, les lymphocytes T et B passent régulièrement dans les organes lymphoïdes secondaires (SLO) qui sont les sites d'initiation de la réponse immunitaire. Les lymphocytes T sont recrutés du sang aux SLO où ils cherchent leur antigène respectif présenté par des cellules dendritiques. Des cellules stromales dans la zone T -nommées fibroblastic reticular cells' (TRC) -sécrètent des chimiokines CCL19 et CCL21 et ainsi facilitent les rencontres entre lymphocytes T et cellules dendritiques. De plus, elles forment un réseau que les lymphocytes T utilisent comme système de guidage. Ce réseau forme des petits canaux (ou conduits) qui permettent le transport rapide, d'antigène soluble ou de cytokines, de la lymphe aux veinules à endothelium épais (HEV). Le phénotype ainsi que les autres fonctions des TRCs demeurent encore à ce jour inconnus. Nous avons trouvé que l'accès des lymphocytes T CD4+ et CD8+ aux ganglions joue un rôle central pour l'homéostasie. Interleukin-7 (IL-7) est un facteur de survie essentiel pour les lymphocytes T naïfs dont la source cellulaire dans la périphérie était mal définie. Nous avons identifié les TRCs dans les ganglions comme source principale d'interleukin-7 (IL-7). In vitro, les TRCs étaient capable de prévenir la mort des lymphocytes T mais pas celle de lymphocytes B grâce à la sécrétion d'IL-7 et de CCL19. En utilisant des souris déficientes du gène CCL19, nous avons observé que l'homéostasie des lymphocytes T dépend aussi de CCL19 in vivo. Les données suggèrent que les TRCs aident à maintenir un répertoire large et diversifié de cellules T et ainsi l'immunocompétence. Pour déterminer si les TRCs pourraient jouer un rote également dans la pathologie, nous avons caractérisé des organes lymphoïdes tertiaires (TLOs) souvent associés avec l'inflammation chronique. Les TLOs ressemblent à des ganglions ou des plaques de Peyer pas seulement en ce qui concerne la présence de lymphocytes. Nous avons constaté que les TLOs forment des réseaux de TRC et un système fonctionnel de conduits. La formation de ces structures est fortement diminuée dans l'absence du signal lymphotoxin ou des cellules connues comme ymphoid tissue-inducer tells: Les TRCs dans les TLOs produisent les chimiokines CCL19, CCL21 et possiblement aussi IL-7 qui sont impliquées dans le développement des TLOs. Les cellules stromales jouent donc un rôle central dans l'initation et la perpétuation des maladies inflamatoires chroniques et pourraient être une cible intéressante pour la thérapie.