Coronary artery disease and revascularization associated with immune checkpoint blocker myocarditis – report from an international registry

Purpose

Immune-checkpoint-blocker (ICB) associated myocarditis (ICB-myocarditis) may present similarly and/or overlap with other cardiac pathology including acute coronary syndrome presenting a challenge for prompt clinical diagnosis.

Methods

An international registry was used to retrospectively identify cases of ICB-myocarditis. Presence of coronary artery disease (CAD) was defined as coronary artery stenosis >70% in patients undergoing coronary angiogram.

Results

Among 261 patients with clinically suspected ICB-myocarditis who underwent a coronary angiography, CAD was present in 59/261 (22.6%) (Table 1). Coronary revascularization was performed during the index hospitalization in 19/59 (32.2%) patients. Patients undergoing coronary revascularization less frequently received steroids administration within 24h of admission compared to the other groups (p=0.029). Myocarditis related 90-day mortality was 9/17 (52.7%) in the revascularized cohort, compared to 5/31 (16.1%) in those not revascularized and 25/156 (16.0%) in those without CAD (p=0.001). irAE-related 90-day mortality was 9/17 (52.7%) in the revascularized cohort, compared to 6/31 (19.4%) in those not revascularized and 31/156 (19.9%) in no CAD groups (p=0.007) (Figure 1). All-cause 90-day mortality was 11/17 (64.7%) in the revascularized cohort, compared to 13/31 (41.9%) in no revascularization and 60/158 (38.0%) in no CAD groups (p=0.10). After adjustment on age and sex, coronary revascularization remained associated with ICB-myocarditis-related death at 90 days (Hazard ratio [HR]=4.03, 95%confidence interval [CI] 1.84–8.84, p<0.001) and was marginally associated with all-cause death (HR=1.88, 95% CI 0.98–3.61, p=0.057).

Conclusion

CAD may exist concomitantly with ICB-myocarditis and portend a poorer outcome when revascularization is performed. This is potentially mediated thru delayed diagnosis and treatment or more severe presentation of ICB-myocarditis.

Funding Acknowledgement

Type of funding sources: None.

A miRNA derived from the 17/92 cluster is a novel player in programming pulmonary hypertension in response to gestational hypoxia via NADPH oxidases and the mTOR pathway

Background

Gestational hypoxia can lead to intrauterine growth restriction (IUGR) and programming of cardiovascular diseases in adulthood via different, although not completely understood, epigenetic mechanisms. We have previously shown that reactive oxygen species (ROS) derived from NADPH oxidases contribute to hypoxia induced pulmonary hypertension (PH). However, their role in disease programming by gestational hypoxia is not resolved.

Purpose

We aimed to elucidate the role of NADPH oxidases and redox sensitive miRNAs in the cardiovascular response of adult offspring to transient gestational hypoxia.

Methods

Wildtype (WT) and nmf333 mice, lacking a functional p22phox dependent NADPH oxidase, were exposed to gestational hypoxia from E10.5 to E11.5. Embryos and adult offspring were analyzed by functional, immunohistochemical and molecular methods including mRNA and miRNA profiling. miRNA mimics or inhibitors were applied in vivo and in vitro using embryoid bodies (EBs). Heart samples from patients with right heart disease associated with congenital heart disease (CHD) were used to validate target miRNA expression.

Results

Transient gestational hypoxia was sufficient to induce IUGR in embryos and pulmonary hypertension (PH) characterized by right ventricular hypertrophy, increased right ventricular pressure and pulmonary vascular remodeling in adult offspring from WT mice while p22phox-deficient nmf333 mice were protected. Cardiac mRNA and miRNA profiling followed by qPCR validation identified several single miRNAs derived from the 17/92 miRNA cluster as downregulated by gestational hypoxia and NADPH oxidases in embryos and adult offspring hearts. In vitro analyses using EBs validated a single miRNA from this cluster to be sufficient to induce cardiac differentiation in response to hypoxia and p22phox, and target analyses identified the mTOR pathway as dysregulated. Treatment with an inhibitor targeting this miRNA was sufficient to induce PH in adult mice, while treating offspring derived from gestational hypoxia pregnancies with an miRNA mimic prevented the development of PH in the adult and dysregulation of the mTOR pathway. Importantly, expression of this single miRNA from the miRNA 17/92 cluster was negatively correlated to right ventricular pressure in CHD patients.

Conclusions

In this study, we demonstrate that gestational hypoxia programs PH in adulthood by upregulating NADPH oxidases and downregulating miRNAs derived from the 17/92 cluster subsequently affecting the mTOR pathway. Since dysregulation of a single miRNA from this cluster induced not only PH but was also associated with right ventricular pressure in CHD patients, these findings might open novel options for diagnosis, prevention and treatment of right heart disease.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): DZHK (German Centre for Cardiovascular Research)

Induktion einer strickleiterartigen Narbe an der Wange einer 28-jährigen Frau nach Laserung eines Naevus araneus mittels KTP-Laser

Die 28-jährige Patientin stellte sich zur Behandlung einer kosmetisch störenden Gefäßläsion an der Wange vor. Es wurde eine Lasertherapie vorgeschlagen und vereinbart. Es entstanden unmittelbar nach der Laserbehandlung Schmerzen und eine Rötung; später eine entstellende Narbe.

Die Gutachter der Gutachterkommission bei der Ärztekammer Nordrhein beurteilten die Behandlung als fehlerhaft.

Laserbehandlungen zählen insgesamt zu den risikoreicheren Therapien in der Dermatologie. Häufiger als andere Behandlungsoptionen beurteilen die Begutachter die Behandlungen als fehlerhaft.

Patientensicherheit: Die Lasertherapie gehört zu den risikoreicheren Therapieoptionen in der Dermatologie

Seit der Erstbeschreibung von Lasern und den ersten Anwendungen in der Dermatologie hat die Lasertherapie innerhalb des dermatologischen therapeutischen Armamentariums enorm an Bedeutung zugenommen.

Da sie häufig bei ästhetischen Indikationen Anwendung findet, sind hohe Sicherheitsanforderungen zu gewährleisten, ansonsten kommt es zu unangenehmen juristischen Streitigkeiten. Eine retrospektive Analyse anhand der Fälle der Gutachterkammer für ärztliche Behandlungsfehler hat gezeigt, dass Lasertherapien zu den risikoreicheren therapeutischen Optionen in der Dermatologie gehören.

Predictors of steroid-refractory immune checkpoint inhibitor associated myocarditis

Background/Introduction

Immune checkpoint inhibitor (ICI)-associated myocarditis has a high mortality rate of approximately 50%. Clinical decompensation often occurs despite first-line treatment with corticosteroids. Factors associated with steroid failure are currently unknown.

Purpose

To identify predictors of steroid failure in patients with ICI-associated myocarditis.

Methods

We developed a web-based registry to collect and study 157 cases with clinical manifestations of ICI-associated myocarditis across 16 countries. Steroid failure was defined as patients who were escalated to immunomodulators after ≥1mg/kg daily dose of prednisone or had in-hospital death due to myocarditis despite ≥1mg/kg daily dose of prednisone. Steroid response was defined as all other patients treated with steroids without escalation to immunomodulators and without death due to myocarditis. A multivariate logistic model accounting for age and sex was used to predict association with steroid failure.

Results

Compared to steroid responsive cases, steroid failure was more likely to result in fulminant myocarditis (56.7% vs 19.6%, OR=5.37 [2.62–10.98] p<0.001) and all-cause in-hospital mortality (49.1% vs 12.9%, OR=6.50 [2.86–14.73] p<0.001) with shorter time from presentation to death (27.5 vs 43.0 days HR: 2.56 [1.45–4.50] p=0.001). When adjusting for age and sex, cases were more likely to be steroid-refractory if they were female (46.7% vs 30.1%, OR=2.77 [1.31–5.85] p=0.007), higher body mass index (27.2 vs 22.0, OR=1.09 [1.01–1.18] p=0.012), had higher intake creatine kinase (2800.5 vs 528.0 U/L, OR=1.48 [1.14–1.90] p=0.003) had higher intake troponin T (1.40 vs 0.25 ng/mL OR=1.63 [1.00–2.64] p=0.049), or had one or more concomitant non-cardiac immune-related adverse event (90.0% vs 74.2%, OR=3.10 [1.14–8.25] p<0.026). The only immune-related adverse events independently associated with steroid failure in myocarditis were myasthenia gravis-like syndrome (26.7% vs 8.2%, OR=3.84 [1.47–10.10] p=0.006) and myositis (45.0% vs 24.7%, OR=2.38 [1.16–4.92] p=0.018). Steroid failure was not significantly associated with cardiovascular or autoimmune history but was associated with a history of thymoma (12.0% vs 2.6%, OR=18.86 [0.10–356.7] p=0.05)

Conclusion(s)

Features such as female sex, high body mass index, and pre-existing thymoma as well as findings of elevated cardiac biomarkers and other non-cardiac immune-related adverse events – particularly myositis and myasthenia gravis-like syndrome – may represent a steroid-refractory phenotype of ICI-associated myocarditis. These results suggest that a multidisciplinary approach to diagnosing concomitant non-cardiac immune related adverse events is key to risk-stratifying ICI-associated myocarditis.

Forrest Plot

Funding Acknowledgement

Type of funding source: Private hospital(s). Main funding source(s): National Institutes of Health

Effects of isoflavones on breast tissue and the thyroid hormone system in humans: a comprehensive safety evaluation

Isoflavones are secondary plant constituents of certain foods and feeds such as soy, linseeds, and red clover. Furthermore, isoflavone-containing preparations are marketed as food supplements and so-called dietary food for special medical purposes to alleviate health complaints of peri- and postmenopausal women. Based on the bioactivity of isoflavones, especially their hormonal properties, there is an ongoing discussion regarding their potential adverse effects on human health. This review evaluates and summarises the evidence from interventional and observational studies addressing potential unintended effects of isoflavones on the female breast in healthy women as well as in breast cancer patients and on the thyroid hormone system. In addition, evidence from animal and in vitro studies considered relevant in this context was taken into account along with their strengths and limitations. Key factors influencing the biological effects of isoflavones, e.g., bioavailability, plasma and tissue concentrations, metabolism, temporality (pre- vs. postmenopausal women), and duration of isoflavone exposure, were also addressed. Final conclusions on the safety of isoflavones are guided by the aim of precautionary consumer protection.

Control of the coherence behavior in a SFG interferometer through the multipump phases command

In this paper, we report on a novel method to control the coherence behavior in a sum frequency generation interferometer powered by two independent pump lines. At the output of the interferometer, the two incoherent fringe patterns must be superimposed to maximize the contrast. The first step consists in canceling the differential group delay. The second one uses the phase control on one pump to synchronize the fringe patterns. This innovative method is experimentally demonstrated with a setup involving a 1544 nm signal and two pump lines around 1064 nm leading to a converted signal around 630 nm. It can be easily extended to a greater number of pump lines.

Contamination of organic nutrient sources with potentially toxic elements, antibiotics and pathogen microorganisms in relation to P fertilizer potential and treatment options for the production of sustainable fertilizers: A review

Organic nutrient sources such as farmyard manure, sewage sludge, their biogas digestates or other animal by-products can be valuable fertilizers delivering organic matter to the soil. Currently, especially phosphorus (P) is in the focus of research since it is an essential plant nutrient with finite resources, estimated to last only for some more decades. Efficient utilization of organic P sources in agriculture will help to preserve P resources and thereby has the potential to close nutrient cycles and prevent unwanted P-losses to the environment, one of the major causes for eutrophication of water bodies. Unfortunately, organic P sources usually contain also various detrimental substances, such as potentially toxic elements or organic contaminants like pharmaceuticals as well as pathogenic microorganisms. Additionally, the utilization of some of these substrates such as sewage sludge or animal by-products is legally limited in agriculture because of the potential risk to contaminate sites with potentially toxic elements and organic contaminants. Thus, to close nutrient cycles it is important to develop solutions for the responsible use of organic nutrient sources. The aim of this review is to give an overview of the contamination of the most important organic nutrient sources with potentially toxic elements, antibiotics (as one important organic contaminant) and pathogenic microorganisms. Changes in manure and sewage sludge management as well as the increasing trend to use such substrates in biogas plants will be discussed with respect to potential risks posed to soils and water bodies. Some examples for abatement options by which contamination can be reduced to produce P fertilizers with high amounts of plant available P forms are presented.

Safety and efficacy of insulin degludec/liraglutide (IDegLira) added to sulphonylurea alone or to sulphonylurea and metformin in insulin-naïve people with Type 2 diabetes: the DUAL IV trial

AIM

To investigate the safety and efficacy of insulin degludec/liraglutide (IDegLira), a novel combination product, as add-on therapy for people with Type 2 diabetes uncontrolled on sulphonylurea therapy.

METHODS

In this 26-week, double-blind trial, adults with Type 2 diabetes [HbA_1c 53-75 mmol/mol (7.0-9.0%)] were randomized to IDegLira (n = 289) or placebo (n = 146) as add-on to pre-trial sulphonylurea ± metformin, titrating to a fasting glycaemic target of 4.0-6.0 mmol/l. Treatment initiation was at 10 dose steps, and maximum dose was 50 dose steps (50 units insulin degludec/1.8 mg liraglutide).

RESULTS

The mean HbA_1c decreased from 63 mmol/mol (7.9%) to 46 mmol/mol (6.4%) with IDegLira and to 57 mmol/mol (7.4%) with placebo [estimated treatment difference -11 mmol/mol (95% CI -13; -10) or -1.02% (95% CI -1.18; -0.87); P < 0.001]. The HbA_1c target of 53 mmol/mol (<7%) was achieved by 79.2% of participants in the IDegLira group vs 28.8% in the placebo group [estimated odds ratio 11.95 (95% CI 7.22; 19.77); P < 0.001]. Mean weight change was +0.5 kg with IDegLira vs -1.0 kg with placebo [estimated treatment difference 1.48 kg (95% CI 0.90; 2.06); P < 0.001]. Confirmed hypoglycaemia occurred in 41.7 and 17.1% of IDegLira- and placebo-treated participants, respectively, with rates of 3.5 vs 1.4 events/patient-years of exposure [estimated rate ratio 3.74 (95% CI 2.28; 6.13); P < 0.001]. IDegLira was generally well tolerated. The rates of serious adverse events were 20.3 and 8.0 per 100 patient-years of exposure with IDegLira and placebo, respectively, without obvious patterns in the type of events.

CONCLUSIONS

IDegLira can be used in people uncontrolled with sulphonylurea ± metformin to improve efficacy with a safety profile in line with previous DUAL trials.

GvHD after umbilical cord blood transplantation for acute leukemia: an analysis of risk factors and effect on outcomes

Using the Center for International Blood and Marrow Transplant Research (CIBMTR) registry, we analyzed 1,404 UCBT patients [single (< 18 years) = 810, double (≥ 18 years) = 594] with acute leukemia to define the incidence of acute and chronic graft-vs.-host disease (GVHD), analyze clinical risk factors and investigate outcomes. After single UCBT, 100-day incidence of grades II–IV aGVHD was 39% (95% CI, 36–43%), grades III–IV aGVHD was 18% (95% CI, 15–20%), and 1-year cGVHD was 27% (95% CI, 24–30%). After double UCBT, 100-day incidence of grades II–IV aGVHD was 45% (95% CI, 41%–49%), grades III–IV aGVHD was 22% (95% CI, 19–26%), and 1-year cGVHD was 26% (95% CI, 22–29%). For single UCBT, multivariate analysis showed that absence of anti-thymocyte globulin (ATG) was associated with aGVHD, whereas prior aGVHD was associated with cGVHD. For double UCBT, absence of ATG and myeloablative conditioning were associated with aGVHD, while prior aGVHD predicted for cGVHD. Grades III–IV aGVHD led to worse survival whereas cGVHD had no significant effect on disease-free or overall survival. GVHD is prevalent after UCBT with severe aGVHD leading to higher mortality. Future research in UCBT should prioritize prevention of GVHD.

Assessment of the diagnostic value of dual-energy CT and MRI in the detection of iatrogenically induced injuries of anterior cruciate ligament in a porcine model

INTRODUCTION

Magnetic resonance imaging (MRI) is the standard of reference for the non-invasive evaluation of ligament injuries of the knee. The development of dual-energy CT (DE-CT) made it possible to differentiate between tissues of different density by two simultaneous CT measurements with different tube voltages. This approach enables DE-CT to discriminate ligament structures without intra-articular contrast media injection. The aims of this study were on the one hand to determine the delineation of the anterior cruciate ligament (ACL) and on the other hand to assess the diagnostic value of DE-CT and MRI in the detection of iatrogenically induced injury of the ACL in a porcine knee joint model.

MATERIALS AND METHODS

Twenty porcine hind legs, which were placed in a preformed cast in order to achieve a standardized position, were scanned using DE-CT. Thereafter, a 1.5-T MRI using a standard protocol was performed. The imaging procedures were repeated with the same parameters after inducing defined lesions (total or partial incision) on the ACL arthroscopically. After post-processing, two radiologists and two orthopedic surgeons first analyzed the delineation of the ACL and then, using a consensus approach, the iatrogenically induced lesions. The result of the arthrotomy was defined as the standard of reference.

RESULTS

The ACL could be visualized both on DE-CT and MRI in 100% of the cases. As for the MRI, the sensitivity and specificity of detecting the cruciate ligament lesion respectively compared with the defined arthrotomy was 66.7% and 78.6% for intact cruciate ligaments, 100% and 75% in the case of a complete lesion, 33.3% and 78.6% for lesions of the anteromedial bundle, and 0% and 100% for lesions of the posterolateral bundle. In comparison, DE-CT demonstrated a sensitivity and specificity of 66.7% and 71.4% in the case of intact cruciate ligaments, 75% and 68.8% in the case of completely discontinued ACLs, 0% and 92.9% in the case of lesions of the anteromedial bundle, and 25% and 87.5% in the case of lesions of the posterolateral bundle.

CONCLUSIONS

The present ex vivo experiment shows that both study modalities (DE-CT and MRI) are equal with regard to the delineation of the ACL, while MRI achieved higher sensitivity and specificity regarding iatrogenically induced complete ACL lesions. DE-CT could be a possible alternative to MRI for certain indications in the diagnosis of a knee ligament injury.

3-Methylcholanthrene (3-MC) and 4-chlorobiphenyl (PCB3) genotoxicity is gender-related in Fischer 344 transgenic rats

Polychlorinated biphenyls (PCBs) are a class of persistent organic pollutants with myriad biological effects, including carcinogenicity. We present data showing gender-specific genotoxicity in Fischer 344 transgenic BigBlue rodents exposed to 4-chlorobiphenyl (PCB3), a hydroxylated metabolite, and the positive control 3-methylcholanthrene (3-MC) where female rats are more resistant to the genotoxic effects of the test compounds compared to their male counterparts. This difference is further highlighted through our examination of gene expression, organ-specific weight changes, and tissue morphology. The purpose of the present study was to explore the complex and multifaceted issues of lower molecular weight PCBs as initiators of carcinogenesis, by examining the mutagenicity of PCB3, a hydroxylated metabolite (4'-OH-PCB3), and 3-methylcholanthrene (3-MC, positive control) in a transgenic rodent model. Previous findings indicated that PCB3 is mutagenic in the liver of male BigBlue transgenic rats under identical exposure conditions. We expected that female rats would be equally, if not more sensitive than male rats, since a 2-year carcinogenesis bioassay with Sprague-Dawley rats and commercial PCB mixtures reported much higher liver cancer rates in female than in male rats. The current study, however, revealed a similar trend in the mutation frequencies across all four treatment groups in females as reported previously in males, but increased variability among animals within each group and a lower overall effect, led to non significant differences in mutation frequencies. A closer analysis of the possible reasons for this negative result using microarray, organ weight and histology data comparisons shows that female Fischer 344 rats 1) had a higher baseline mutation frequency in the corn oil control group and greater variability than male rats; 2) responded with robust gene expression changes, which may also play a role in our observation of 3) highly increased liver, spleen, and lung weight in 3-MC and PCB3-treated female rats and thus changed distribution and kinetics of the test compounds. Our analysis indicates that female transgenic BigBlue Fischer 344 rats are more resistant to PCB3 and 3-MC genotoxicity compared to their male counterparts.

Cumulative cultural dynamics and the coevolution of cultural innovation and transmission: an ESS model for panmictic and structured populations

When individuals in a population can acquire traits through learning, each individual may express a certain number of distinct cultural traits. These traits may have been either invented by the individual himself or acquired from others in the population. Here, we develop a game theoretic model for the accumulation of cultural traits through individual and social learning. We explore how the rates of innovation, decay, and transmission of cultural traits affect the evolutionary stable (ES) levels of individual and social learning and the number of cultural traits expressed by an individual when cultural dynamics are at a steady-state. We explore the evolution of these phenotypes in both panmictic and structured population settings. Our results suggest that in panmictic populations, the ES level of learning and number of traits tend to be independent of the social transmission rate of cultural traits and is mainly affected by the innovation and decay rates. By contrast, in structured populations, where interactions occur between relatives, the ES level of learning and the number of traits per individual can be increased (relative to the panmictic case) and may then markedly depend on the transmission rate of cultural traits. This suggests that kin selection may be one additional solution to Rogers's paradox of nonadaptive culture.

Is sociality driven by the costs of dispersal or the benefits of philopatry? A role for kin-discrimination mechanisms

The role of ecological constraints in promoting sociality is currently much debated. Using a direct-fitness approach, we show this role to depend on the kin-discrimination mechanisms underlying social interactions. Altruism cannot evolve under spatially based discrimination, unless ecological constraints prevent complete dispersal. Increasing constraints enhances both the proportion of philopatric (and thereby altruistic) individuals and the level of altruistic investments conceded in pairwise interactions. Familiarity-based discrimination, by contrast, allows philopatry and altruism to evolve at significant levels even in the absence of ecological constraints. Increasing constraints further enhances the proportion of philopatric (and thereby altruistic) individuals but not the level of altruism conceded. Ecological constraints are thus more likely to affect social evolution in species in which restricted cognitive abilities, large group size, and/or limited period of associative learning force investments to be made on the basis of spatial cues.

The evolution of trans-generational altruism: kin selection meets niche construction

A cornerstone result of sociobiology states that limited dispersal can induce kin competition to offset the kin selected benefits of altruism. Several mechanisms have been proposed to circumvent this dilemma but all assume that actors and recipients of altruism interact during the same time period. Here, this assumption is relaxed and a model is developed where individuals express an altruistic act, which results in posthumously helping relatives living in the future. The analysis of this model suggests that kin selected benefits can then feedback on the evolution of the trait in a way that promotes altruistic helping at high rates under limited dispersal. The decoupling of kin competition and kin selected benefits results from the fact that by helping relatives living in the future, an actor is helping individuals that are not in direct competition with itself. A direct consequence is that behaviours which actors gain by reducing the common good of present and future generations can be opposed by kin selection. The present model integrates niche-constructing traits with kin selection theory and delineates demographic and ecological conditions under which altruism can be selected for; and conditions where the 'tragedy of the commons' can be reduced.

Communication and understanding of prognosis among stage IV lung and GI cancer patients

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Background: Patients' understanding of prognosis is essential to informed decision making about treatment options. There is little data on what prognostic information oncologists communicate to patients and what patients actually understand about their prognosis. Methods: We audio taped consultations between 90 newly diagnosed stage IV non small cell lung cancer patients and stage IV GI cancer patients and medical oncologists at academic teaching hospitals. Interactions were audio taped until patients arrived at a treatment decision. Audiotapes were digitized, coded and analyzed using the RIAS system. All conversation relating to prognosis was blocked, coded and analyzed. After meeting with an oncologist patients were surveyed about their understanding of prognosis and desire for information about life expectancy. Results: 276 patients were contacted of whom 190 consented to participate. 87 patients were ineligible, 13 patients withdrew from the study, and complete data were obtained on 90 patients. The mean age of participants was 62 years (±11), 65% were women. Analysis of the audiotapes revealed that in 78% of cases oncologists told patients that their cancer was not curable. When patients were surveyed, however, only 32% of those who were told that their cancer was not curable actually understood that there was no cure for their cancer (CI 0.19–0.45). Patients’ age, gender, education, and marital status were not associated with an understanding of prognosis. Patient factors associated with understanding of prognosis included a desire for good and bad medical information (CI 0.75–0.99; p<0.0001), an interest in knowing the likelihood that treatment would cure their disease (CI 0.54–0.94; p<0.01), and a belief that information about life expectancy would influence their medical decisions (CI 0.56–0.94; p<0.01). Conclusion: In a majority of cases oncologists actually told patients that their cancer is not curable. Most patients, however, did not understand what was communicated. Patients’ understanding of prognosis is determined not only by what oncologists communicate, but also by patients’ desire for prognostic information.

No significant financial relationships to disclose.

Evaluation of the probe dihydrocalcein acetoxymethylester as an indicator of reactive oxygen species formation and comparison with oxidative DNA base modification determined by modified alkaline elution technique

Reactive oxygen species (ROS) play a predominant role in various diseases and the development of fast and easy methods for the quantification of intracellular ROS represents an important goal. Therefore, the aim of the present study was the evaluation of the fluorogenic probe dihydrocalcein acetoxymethylester (AM) for the detection of intracellular ROS. A flow cytometric method was developed using MCF-7 cells and the kinetics of ester hydrolysis and the cellular distribution and stability of calcein were characterized using calcein AM. Then, MCF-7 cells were challenged with model agents for the generation of singlet oxygen (illumination with visible light), peroxyl and hydroxyl radicals (tert-butylhydroperoxide, tBHP), superoxide anion radicals (potassium dioxide), and the intracellular formation of superoxide anion radicals by redox cycling (menadione) and the formation of calcein was compared with the induction of oxidative DNA base modifications assessed by modified alkaline elution technique. Every model agent significantly induced formamidopyrimidine-DNA glycosylase-sensitive sites (i.e. oxidative DNA base modifications) and most also induced DNA strand breaks. In contrast, exclusively tBHP and illumination with visible light induced the intracellular formation of calcein. In conclusion, though intracellular oxidation of dihydrocalcein represents a fast screening method, it detects a limited spectrum of ROS.

Artificial organs: a new option for treating osteoarthritis

Osteoarthritis is usually regarded as a localized disease whose optimal treatment is a therapy applied directly to the affected joint. Unfortunately, current local therapies such as repeated intraarticular injections or constant infusions are associated with a higher risk of infection. One way to overcome this would be to transfer substances made locally by cells within the joint. However, attempts using direct vector transfers or intraarticular injections of ex vivo modified cells could not achieve a sustained protein secretion over several months. Another method of delivering biological factors (i.e.growth hormones) intraarticularly is to transplant an artificial organ, capable of supporting the regeneration of natural cartilage, directly into the affected joint The main difficulty of having to produce bioactive factors over a long period of time is overcome by implanting a chamber-like system filled with either genetically modified cells or a drug-releasing matrix. This drug delivery system would be located at a peripheral site of the joint and could release substances directly into the joint cavity which would be transported via the synovial fluid and/or diffused to the chondrocytes or synoviocytes.

An evolutionary analysis of the relationship between spite and altruism

We investigate the selective pressures on a social trait when evolution occurs in a population of constant size. We show that any social trait that is spiteful simultaneously qualifies as altruistic. In other words, any trait that reduces the fitness of less related individuals necessarily increases that of related ones. Our analysis demonstrates that the distinction between "Hamiltonian spite" and "Wilsonian spite" is not justified on the basis of fitness effects. We illustrate this general result with an explicit model for the evolution of a social act that reduces the recipient's survival ("harming trait"). This model shows that the evolution of harming is favoured if local demes are of small size and migration is low (philopatry). Further, deme size and migration rate determine whether harming evolves as a selfish strategy by increasing the fitness of the actor, or as a spiteful/altruistic strategy through its positive effect on the fitness of close kin.

The evolution of cooperation and altruism--a general framework and a classification of models

One of the enduring puzzles in biology and the social sciences is the origin and persistence of intraspecific cooperation and altruism in humans and other species. Hundreds of theoretical models have been proposed and there is much confusion about the relationship between these models. To clarify the situation, we developed a synthetic conceptual framework that delineates the conditions necessary for the evolution of altruism and cooperation. We show that at least one of the four following conditions needs to be fulfilled: direct benefits to the focal individual performing a cooperative act; direct or indirect information allowing a better than random guess about whether a given individual will behave cooperatively in repeated reciprocal interactions; preferential interactions between related individuals; and genetic correlation between genes coding for altruism and phenotypic traits that can be identified. When one or more of these conditions are met, altruism or cooperation can evolve if the cost-to-benefit ratio of altruistic and cooperative acts is greater than a threshold value. The cost-to-benefit ratio can be altered by coercion, punishment and policing which therefore act as mechanisms facilitating the evolution of altruism and cooperation. All the models proposed so far are explicitly or implicitly built on these general principles, allowing us to classify them into four general categories.