Using random assignment to measure court accessibility for low-income divorce seekers.

We conducted a field experiment in which 311 low-income individuals seeking a divorce were randomly assigned to receive access to a pro bono lawyer (versus minimal help) to assist with filing for divorce. Examining court records, we found that assignment to an attorney made a large difference in whether participants filed for and obtained a divorce. Three years after randomization, 46% of the treated group had terminated their marriages in the proper legal venue, compared to 9% of the control group. Among "compliers"-participants who obtained representation only if assigned to receive it-those with lawyers were far more likely to file for and obtain a divorce than those not assigned lawyers. Because divorce implicates fundamental constitutional interests and can be effectuated only by resort to the courts, the US Constitution requires that dissolution of marriage be made achievable regardless of ability to pay. Yet, we observed few low-income individuals who were able to initiate divorce suits on their own. Through interviews and archival research, we identified barriers that low-income litigants faced in navigating the divorce system, including mandatory wait times, limited hours at important facilities, and burdensome paperwork sometimes requiring access to photocopiers and typewriters. This study therefore documents a salient instance in which a civil legal process was inaccessible to those without lawyers, even though their legal issues were straightforward, involving few if any matters for courts to adjudicate.

Serotonergic innervation of the amygdala is increased in autism spectrum disorder and decreased in Williams syndrome.

BACKGROUND: Williams syndrome (WS) and autism spectrum disorder (ASD) are neurodevelopmental disorders that demonstrate overlapping genetic associations, dichotomous sociobehavioral phenotypes, and dichotomous pathological differences in neuronal distribution in key social brain areas, including the prefrontal cortex and the amygdala. The serotonergic system is critical to many processes underlying neurodevelopment and is additionally an important neuromodulator associated with behavioral variation. The amygdala is heavily innervated by serotonergic projections, suggesting that the serotonergic system is a significant mediator of neuronal activity. Disruptions to the serotonergic system, and atypical structure and function of the amygdala, are implicated in both WS and ASD. METHODS: We quantified the serotonergic axon density in the four major subdivisions of the amygdala in the postmortem brains of individuals diagnosed with ASD and WS and neurotypical (NT) brains. RESULTS: We found opposing directions of change in serotonergic innervation in the two disorders, with ASD displaying an increase in serotonergic axons compared to NT and WS displaying a decrease. Significant differences (p < 0.05) were observed between WS and ASD data sets across multiple amygdala nuclei. LIMITATIONS: This study is limited by the availability of human postmortem tissue. Small sample size is an unavoidable limitation of most postmortem human brain research and particularly postmortem research in rare disorders. CONCLUSIONS: Differential alterations to serotonergic innervation of the amygdala may contribute to differences in sociobehavioral phenotype in WS and ASD. These findings will inform future work identifying targets for future therapeutics in these and other disorders characterized by atypical social behavior.

Local photocurrent mapping and cell performance behaviour on a nanometre scale for monolithically interconnected Cu(In,Ga)Se2 solar cells.

The local efficiency of lamellar shaped Cu(In,Ga)Se2 solar cells has been investigated using scanning near-field optical microscopy (SNOM). Topographic and photocurrent measurements have been performed simultaneously with a 100 nm tip aperture. The lamellar shaped solar cell with monolithic interconnects (P scribe) has been investigated on a nanometre scale for the first time at different regions using SNOM. It was found that, the cell region between P1 and P2 significantly contributes to the solar cells overall photocurrent generation. The photocurrent produced depends locally on the sample topography and it is concluded that it is mainly due to roughness changes of the ZnO:Al/i-ZnO top electrode. Regions lying under large grains of ZnO produce significantly less current than regions under small granules. The observed photocurrent features were allocated primarily to the ZnO:Al/i-ZnO top electrode. They were found to be independent of the wavelength of the light used (532 nm and 633 nm).

Evolution of opto-electronic properties during film formation of complex semiconductors.

Optical and electrical properties of complex semiconducting alloys like Cu(In,Ga)Se2 (CIGS) are strongly influenced by the reaction pathways occurring during their deposition process. This makes it desirable to observe and control these properties in real-time during the deposition. Here we show for the first time the evolution of the band gap and the sub-band-gap defect absorption of CIGS thin film as well as surface roughness during a three-stage co-evaporation process by means of an optical analysis technique, based on white light reflectometry (WLR). By simultaneously recording structural information with in-situ energy dispersive X-ray diffraction and X-ray fluorescence we can directly correlate the evolution of opto-electronic material parameters with the structural properties of the film during growth. We find that the surface roughness and the sub-gap light absorption can be correlated with the phase evolution during the transformation from (In,Ga)2Se3 to Cu(In,Ga)Se2 by the incorporation of Cu into the film. Sub-bandgap light absorption is found to be influenced by the Cu-saturated growth phase and is lowered close to the points of stoichiometry, allowing for an advanced process design.

Humanized Mouse Models for Transplant Immunology.

Our understanding of the molecular pathways that control immune responses, particularly immunomodulatory molecules that control the extent and duration of an immune response, have led to new approaches in the field of transplantation immunology to induce allograft survival. These molecular pathways are being defined precisely in murine models and translated into clinical practice; however, many of the newly available drugs are human-specific reagents. Furthermore, many species-specific differences exist between mouse and human immune systems. Recent advances in the development of humanized mice, namely, immunodeficient mice engrafted with functional human immune systems, have led to the availability of a small animal model for the study of human immune responses. Humanized mice represent an important preclinical model system for evaluation of new drugs and identification of the mechanisms underlying human allograft rejection without putting patients at risk. This review highlights recent advances in the development of humanized mice and their use as preclinical models for the study of human allograft responses.

IMP3 promotes stem-like properties in triple-negative breast cancer by regulating SLUG.

IMP3 (insulin-like growth factor-2 mRNA binding protein 3) is an oncofetal protein whose expression is prognostic for poor outcome in several cancers. Although IMP3 is expressed preferentially in triple-negative breast cancer (TNBC), its function is poorly understood. We observed that IMP3 expression is significantly higher in tumor initiating than in non-tumor initiating breast cancer cells and we demonstrate that IMP3 contributes to self-renewal and tumor initiation, properties associated with cancer stem cells (CSCs). The mechanism by which IMP3 contributes to this phenotype involves its ability to induce the stem cell factor SOX2. IMP3 does not interact with SOX2 mRNA significantly or regulate SOX2 expression directly. We discovered that IMP3 binds avidly to SNAI2 (SLUG) mRNA and regulates its expression by binding to the 5' UTR. This finding is significant because SLUG has been implicated in breast CSCs and TNBC. Moreover, we show that SOX2 is a transcriptional target of SLUG. These data establish a novel mechanism of breast tumor initiation involving IMP3 and they provide a rationale for its association with aggressive disease and poor outcome.

Generation of ß cell-specific human cytotoxic T cells by lentiviral transduction and their survival in immunodeficient human leucocyte antigen-transgenic mice.

Several ß cell antigens recognized by T cells in the non-obese diabetic (NOD) mouse model of type 1 diabetes (T1D) are also T cell targets in the human disease. While numerous antigen-specific therapies prevent diabetes in NOD mice, successful translation of rodent findings to patients has been difficult. A human leucocyte antigen (HLA)-transgenic mouse model incorporating human ß cell-specific T cells might provide a better platform for evaluating antigen-specific therapies. The ability to study such T cells is limited by their low frequency in peripheral blood and the difficulty in obtaining islet-infiltrating T cells from patients. We have worked to overcome this limitation by using lentiviral transduction to 'reprogram' primary human CD8 T cells to express three T cell receptors (TCRs) specific for a peptide derived from the ß cell antigen islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP265-273 ) and recognized in the context of the human class I major histocompatibility complex (MHC) molecule HLA-A2. The TCRs bound peptide/MHC multimers with a range of avidities, but all bound with at least 10-fold lower avidity than the anti-viral TCR used for comparison. One exhibited antigenic recognition promiscuity. The ß cell-specific human CD8 T cells generated by lentiviral transduction with one of the TCRs released interferon (IFN)-γ in response to antigen and exhibited cytotoxic activity against peptide-pulsed target cells. The cells engrafted in HLA-A2-transgenic NOD-scid IL2rγ(null) mice and could be detected in the blood, spleen and pancreas up to 5 weeks post-transfer, suggesting the utility of this approach for the evaluation of T cell-modulatory therapies for T1D and other T cell-mediated autoimmune diseases.

Extensive double humanization of both liver and hematopoiesis in FRGN mice.

Preclinical research in animals often fails to adequately predict the outcomes observed in human patients. Chimeric animals bearing individual human tissues have been developed to provide improved models of human-specific cellular processes. Mice transplanted with human hematopoietic stem cells can be used to study human immune responses, infections of blood cells and processes of hematopoiesis. Animals with humanized livers are useful for modeling hepatotropic infections as well as drug metabolism and hepatotoxicity. However, many pathophysiologic processes involve both the liver and the hematolymphoid system. Examples include hepatitis C/HIV co-infection, immune mediated liver diseases, liver injuries with inflammation such as steatohepatitis and alcoholic liver disease. We developed a robust protocol enabling the concurrent double-humanization of mice with mature hepatocytes and human blood. Immune-deficient, fumarylacetoacetate hydrolase (Fah(-/-)), Rag2(-/-) and Il2rg(-/-) deficient animals on the NOD-strain background (FRGN) were simultaneously co-transplanted with adult human hepatocytes and hematopoietic stem cells after busulfan and Ad:uPA pre-conditioning. Four months after transplantation the average human liver repopulation exceeded 80% and hematopoietic chimerism also was high (40-80% in bone marrow). Importantly, human macrophages (Kupffer cells) were present in the chimeric livers. Double-chimeric FRGN mice will serve as a new model for disease processes that involve interactions between hepatocytes and hematolymphoid cells.

Systemic delivery of triplex-forming PNA and donor DNA by nanoparticles mediates site-specific genome editing of human hematopoietic cells in vivo.

In vivo delivery is a major barrier to the use of molecular tools for gene modification. Here we demonstrate site-specific gene editing of human cells in vivo in hematopoietic stem cell-engrafted NOD.Cg-Prkdc(scid)IL2rγ(tm1Wjl) (abbreviated NOD-scid IL2rγ(null)) mice, using biodegradable nanoparticles loaded with triplex-forming peptide nucleic acids (PNAs) and single-stranded donor DNA molecules. In vitro screening showed greater efficacy of nanoparticles containing PNAs/DNAs together over PNA-alone or DNA-alone. Intravenous injection of particles containing PNAs/DNAs produced modification of the human CCR5 gene in hematolymphoid cells in the mice, with modification confirmed at the genomic DNA, mRNA and functional levels. Deep sequencing revealed in vivo modification of the CCR5 gene at frequencies of 0.43% in hematopoietic cells in the spleen and 0.05% in the bone marrow: off-target modification in the partially homologous CCR2 gene was two orders of magnitude lower. We also induced specific modification in the ß-globin gene using nanoparticles carrying ß-globin-targeted PNAs/DNAs, demonstrating this method's versatility. In vivo testing in an enhanced green fluorescent protein-ß-globin reporter mouse showed greater activity of nanoparticles containing PNAs/DNAs together over DNA only. Direct in vivo gene modification, such as we demonstrate here, would allow for gene therapy in systemic diseases or in cells that cannot be manipulated ex vivo.

Effect of added dead space on sleep disordered breathing at high altitude.

OBJECTIVE: Sleep disordered breathing with central apnea or hypopnea frequently occurs at high altitude and is thought to be caused by a decrease in blood CO(2) level. The aim of this study was to assess the effects of added respiratory dead space on sleep disordered breathing. METHODS: Full polysomnographies were performed on 12 unacclimatized swiss mountaineers (11 males, 1 female, mean age 39 ± 12 y.o.) in Leh, Ladakh (3500 m). In random order, half of the night was spent with a 500 ml increase in dead space through a custom designed full face mask and the other half without it. RESULTS: Baseline data revealed two clearly distinct groups: one with severe sleep disordered breathing (n=5, AHI>30) and the other with moderate to no disordered breathing (n=7, AHI<30). DS markedly improved breathing in the first group (baseline vs DS): apnea hypopnea index (AHI) 70.3 ± 25.8 vs 29.4 ± 6.9 (p=0.013), oxygen desaturation index (ODI): 72.9 ± 24.1/h vs 42.5 ± 14.4 (p=0.031), whereas it had no significant effect in the second group or in the total population. Respiratory events were almost exclusively central apnea or hypopnea. Microarousal index, sleep efficiency, and sleep architecture remained unchanged with DS. A minor increase in mean PtcCO(2) (n=3) was observed with DS. CONCLUSION: A 500 ml increase in dead space through a fitted mask may improve nocturnal breathing in mountaineers with severe altitude-induced sleep disordered breathing.

Allografts stimulate cross-reactive virus-specific memory CD8 T cells with private specificity.

Viral infections have been associated with the rejection of transplanted allografts in humans and mice, and the induction of tolerance to allogeneic tissues in mice is abrogated by an ongoing viral infection and inhibited in virus-immune mice. One proposed mechanism for this 'heterologous immunity' is the induction of alloreactive T cell responses that cross-react with virus-derived antigens. These cross-reactive CD8 T cells are generated during acute viral infection and survive into memory, but their ability to partake in the immune response to allografts in vivo is not known. We show here that cross-reactive, virus-specific memory CD8 T cells from mice infected with LCMV proliferated in response to allografts. CD8 T cells specific to several LCMV epitopes proliferated in response to alloantigens, with the magnitude and hierarchy of epitope-specific responses varying with the private specificities of the host memory T cell repertoire, as shown by adoptive transfer studies. Last, we show that purified LCMV-specific CD8 T cells rejected skin allografts in SCID mice. These findings therefore implicate a potential role for heterologous immunity in virus-induced allograft rejection.

AATF mediates an antiapoptotic effect of the unfolded protein response through transcriptional regulation of AKT1.

Endoplasmic reticulum (ER) stress-mediated cell death has an important role in the pathogenesis of chronic diseases, including diabetes and neurodegeneration. Although proapoptotic programs activated by ER stress have been extensively studied, identification and characterization of antiapoptotic programs that counteract ER stress are currently incomplete. Through the gene expression profiling of beta-cells lacking Wolfram syndrome 1 gene (WFS1), a causative gene for Wolfram syndrome, we discovered a novel antiapoptotic gene of the unfolded protein response (UPR), apoptosis antagonizing transcription factor (AATF). Here, we study the regulation of AATF, identify its target genes, and determine the basis for its antiapoptotic activities in response to ER stress. We show that AATF is induced by ER stress through the PERK-eIF2alpha pathway and transcriptionally activates the v-akt murine thymoma viral oncogene homolog 1 (AKT1) gene through signal transducer and activator of transcription 3 (Stat3), which sustains Akt1 activation and promotes cell survival. Ectopic expression of AATF or a constitutively active form of AKT1 confers on cells resistance to ER stress-mediated cell death, whereas RNAi-mediated knockdown of AATF or AKT1 renders cells sensitive to ER stress. We also discovered a positive crosstalk between the AATF and WFS1 signaling pathways. Thus, WFS1 deficiency or AATF deficiency mediates a self-perpetuating cycle of cell death. Our results reveal a novel antiapoptotic program relevant to the treatment of diseases caused by ER stress-mediated cell death.

Human peripheral blood leucocyte non-obese diabetic-severe combined immunodeficiency interleukin-2 receptor gamma chain gene mouse model of xenogeneic graft-versus-host-like disease and the role of host major histocompatibility complex.

Immunodeficient non-obese diabetic (NOD)-severe combined immune-deficient (scid) mice bearing a targeted mutation in the gene encoding the interleukin (IL)-2 receptor gamma chain gene (IL2rgamma(null)) engraft readily with human peripheral blood mononuclear cells (PBMC). Here, we report a robust model of xenogeneic graft-versus-host-like disease (GVHD) based on intravenous injection of human PBMC into 2 Gy conditioned NOD-scid IL2rgamma(null) mice. These mice develop xenogeneic GVHD consistently (100%) following injection of as few as 5 x 10(6) PBMC, regardless of the PBMC donor used. As in human disease, the development of xenogeneic GVHD is highly dependent on expression of host major histocompatibility complex class I and class II molecules and is associated with severely depressed haematopoiesis. Interrupting the tumour necrosis factor-alpha signalling cascade with etanercept, a therapeutic drug in clinical trials for the treatment of human GVHD, delays the onset and progression of disease. This model now provides the opportunity to investigate in vivo mechanisms of xenogeneic GVHD as well as to assess the efficacy of therapeutic agents rapidly.

Non-obese diabetic-recombination activating gene-1 (NOD-Rag1 null) interleukin (IL)-2 receptor common gamma chain (IL2r gamma null) null mice: a radioresistant model for human lymphohaematopoietic engraftment.

Immunodeficient hosts engrafted with human lymphohaematopoietic cells hold great promise as a preclinical bridge for understanding human haematopoiesis and immunity. We now describe a new immunodeficient radioresistant non-obese diabetic mice (NOD) stock based on targeted mutations in the recombination activating gene-1 (Rag1(null)) and interleukin (IL)-2 receptor common gamma chain (IL2rgamma(null)), and compare its ability to support lymphohaematopoietic cell engraftment with that achieved in radiosensitive NOD.CB17-Prkdc(scid) (NOD-Prkdc(scid)) IL2rgamma(null) mice. We observed that immunodeficient NOD-Rag1(null) IL2rgamma(null) mice tolerated much higher levels of irradiation conditioning than did NOD-Prkdc(scid) IL2rgamma(null) mice. High levels of human cord blood stem cell engraftment were observed in both stocks of irradiation-conditioned adult mice, leading to multi-lineage haematopoietic cell populations and a complete repertoire of human immune cells, including human T cells. Human peripheral blood mononuclear cells also engrafted at high levels in unconditioned adult mice of each stock. These data document that Rag1(null) and scid stocks of immunodeficient NOD mice harbouring the IL2rgamma(null) mutation support similar levels of human lymphohaematopoietic cell engraftment. NOD-Rag1(null) IL2rgamma(null) mice will be an important new model for human lymphohaematopoietic cell engraftment studies that require radioresistant hosts.

A new immunodeficient hyperglycaemic mouse model based on the Ins2Akita mutation for analyses of human islet and beta stem and progenitor cell function.

AIMS/HYPOTHESIS: To develop and validate a new immunodeficient mouse strain that spontaneously develops a non-autoimmune hyperglycaemia to serve as a diabetic host for human islets and human beta stem and progenitor cells without the need for induction of hyperglycaemia by toxic chemicals with their associated side effects. METHODS: We generated and characterised a new strain of immunodeficient spontaneously hyperglycaemic mice, the NOD-Rag1null Prf1null Ins2Akita strain and compared this strain with the NOD-scid Il2rgammanull (also known as Il2rg) immunodeficient strain rendered hyperglycaemic by administration of a single dose of streptozotocin. Hyperglycaemic mice were transplanted with human islets ranging from 1,000 to 4,000 islet equivalents (IEQ) and were monitored for normalisation of blood glucose levels. RESULTS: NOD-Rag1null Prf1null Ins2Akita mice developed spontaneous hyperglycaemia, similar to Ins2Akita-harbouring strains of immunocompetent mice. Histological examination of islets in the host pancreas validated the spontaneous loss of beta cell mass in the absence of mononuclear cell infiltration. Human islets transplanted into spontaneously diabetic NOD-Rag1null Prf1null Ins2Akita and chemically diabetic NOD-scid Il2rgammanull mice resulted in a return to euglycaemia that occurred with transplantation of similar beta cell masses. CONCLUSIONS/INTERPRETATION: The NOD-Rag1null Prf1null Ins2Akita mouse is the first immunodeficient, spontaneously hyperglycaemic mouse strain described that is based on the Ins2Akita mutation. This strain is suitable as hosts for human islet and human beta stem and progenitor cell transplantation in the absence of the need for pharmacological induction of diabetes. This strain of mice also has low levels of innate immunity and can be engrafted with a human immune system for the study of human islet allograft rejection.

Humanized SCID mouse models for biomedical research.

There is a growing need for effective animal models to carry out experimental studies on human hematopoietic and immune systems without putting individuals at risk. Progress in development of small animal models for the in vivo investigation of human hematopoiesis and immunity has seen three major breakthroughs over the last three decades. First, CB 17-Prkdc(scid) (abbreviated CB 17-scid) mice were discovered in 1983, and engraftment of these mice with human fetal tissues (SCID-Hu model) and peripheral blood mononuclear cells (Hu-PBL-SCID model) was reported in 1988. Second, NOD-scid mice were developed and their enhanced ability to engraft with human hematolymphoid tissues as compared with CB17-scid mice was reported in 1995. NOD-scid mice have been the "gold standard" for studies of human hematolymphoid engraftment in small animal models over the last 10 years. Third, immunodeficient mice bearing a targeted mutation in the IL-2 receptor common gamma chain (IL2rgamma(null)) were developed independently by four groups between 2002 and 2005, and a major increase in the engraftment and function of human hematolymphoid cells as compared with NOD-scid mice has been reported. These new strains of immunodeficient IL2rgamma(null) mice are now being used for studies in human hematopoiesis, innate and adaptive immunity, autoimmunity, infectious diseases, cancer biology, and regenerative medicine. In this chapter, we discuss the current state of development of these strains of mice, the remaining deficiencies, and how approaches used to increase the engraftment and function of human hematolymphoid cells in CB 17-scid mice and in previous models based on NOD-scid mice may enhance human hematolymphoid engraftment and function in NOD-scid IL2rgamma(null) mice.

Determinants of memory in experimental filarial infections in mice.

In this communication, we examine the determinants and duration of memory responses against filarial parasites using an intraperitoneal mouse model of Brugia pahangi infection. We assessed the role of T cells in the memory response against B. pahangi larvae by transferring splenic T cells from wild-type mice primed with L3 into T-cell-deficient mice. We found that mice reconstituted with primed T cells cleared intraperitoneal infections with infective larvae in an accelerated manner. To determine the components that may be responsible for the memory response, we transferred unfractionated T cells or purified CD4+ T cells or CD8+ T cells from BALB/cByJ mice primed a month earlier with L3 into T-cell-deficient BALB/c TCRbeta-/- mice. Recipients were challenged 10 days after adoptive transfer. Our data demonstrated that while either CD4+ or CD8+ T cells are able to confer some level of protection, both are required for an optimal recall response. To evaluate the longevity of the memory response, we primed several groups of wild-type mice at different times over a year. These mice were then challenged with a single injection of B. pahangi L3. The gap between the priming and second injections of larvae ranged between 4 and 60 weeks. We found that the memory responses in BALB/cByJ mice lasted over a year whereas those in C57BL/6 mice waned more rapidly.

Different mechanisms control peripheral and central tolerance in hematopoietic chimeric mice.

Regulatory T cells (Treg) are important in peripheral tolerance, but their role in establishing and maintaining hematopoietic mixed chimerism and generating central tolerance is unclear. We now show that costimulation blockade using a donor-specific transfusion and anti-CD154 antibody applied to mice given bone marrow and simultaneously transplanted with skin allografts leads to hematopoietic chimerism and permanent skin allograft survival. Chimeric mice bearing intact skin allografts fail to generate effector/memory T cells against allogeneic targets as shown by the absence of IFNgamma-producing CD44(high)CD8+ T cells and in vivo cytotoxicity. Depletion of Tregs by injection of anti-CD4 or anti-CD25 antibody prior to costimulation blockade prevents chimerism, shortens skin allograft survival and leads to generation of effector/memory cytotoxic T cells. Depletion of Tregs by injection of anti-CD4 or anti-CD25 antibody two months after transplantation leads to loss of skin allografts even though mice remain chimeric and exhibit little in vivo cytotoxicity. In contrast, chimerism is lost, but skin allografts survive following naïve T-cell injection. We conclude that hematopoietic chimerism and peripheral tolerance may be maintained by different mechanisms in mixed hematopoietic chimeras.

Multiple drug prescribing by general practitioners in a German region: Implications for drug interactions and patient safety.

OBJECTIVE: An increased number of drugs used by patients enhances the risk of potentially hazardous drug interactions. So far, no representative data are available about how common this problem is in German general practices. METHODS: We performed a retrospective analysis using a prescription database for a German region. The 50 general practitioners (out of 1,457) who wrote the most prescriptions during January to March 2003 were included. Data on 4,153 patients who were prescribed at least 10 drugs were analyzed for 92 predefined Drug Combinations Prone to Interact (DCPI) to a clinically relevant extent and possible contraindications. RESULTS: From 92 DCPIs, 71 occurred in the analyzed population between 1 and 275 times. The total number of DCPI cases was 1,295, which included 10% (n = 129) of contraindicated combinations. Among 4,153 analyzed patients, 822 patients (19.8%) were affected by at least 1 DCPI. In 268 patients (6.5%), multiple DCPIs occurred. The most frequently found drug pairs were digitalis/diuretics, digitalis/calcium channel blockers, and theophylline/quinolones. Among contraindicated combinations, tricyclic antidepressants, St. John's wort and antiarrhythmic drugs were most frequently involved. In about 1/3 of patients treated for chronic heart failure, pharmacotherapy appeared not to be guideline-adherent. CONCLUSION: Drug interactions, especially in polypharmacotherapy, represent a potential hazard which must be taken into account by the prescribing physician. Our study is the first to use a prescription database for the evaluation of drug prescriptions within a German region.