An investigation of sleep problems, gastrointestinal symptoms, comorbid psychopathology and challenging behavior in children and adolescents with Down Syndrome.

BACKGROUND: Down syndrome (DS) is one of the most common chromosomal abnormalities, and children with DS have increased risks of receiving diagnoses of specific comorbidities. AIMS: This study aimed to assess the frequencies and relationships between sleep problems, gastrointestinal (GI) symptoms, comorbid psychopathology, and challenging behavior. METHODS AND PROCEDURES: The Children's Sleep Habits Questionnaire, Gastrointestinal Symptom Inventory, Autism Spectrum Disorder-Comorbid for Children, and Behavior Problems Inventory-Short Form were completed by 123 parents of children and adolescents with DS. OUTCOMES AND RESULTS: The frequency of GI symptoms was 74.8 %, with high frequencies also found for: sleep problems (100 %), challenging behavior (100 %), and moderate to severe levels of comorbid psychopathology (tantrum=80 %; repetitive behavior=63 %; avoidant behavior=82 %; worry/depressed=61 %; conduct behavior=100 %; over-eating=100 %; under-eating=100 %). A significant moderate correlation was found between total GI symptoms and self-injurious behavior frequency. Children who presented with abdominal pain engaged in self-injurious behavior more frequently than those with no abdominal pain. CONCLUSIONS AND IMPLICATIONS: Findings indicated a high frequency of sleep problems, comorbid psychopathology, GI symptoms, and challenging behavior and demonstrated a relationship between GI symptoms and self-injurious behavior in children and adolescents with DS. This research illustrated the importance of investigating comorbid conditions in individuals with DS. WHAT THIS PAPER ADDS?: Down Syndrome (DS) is a genetic condition characterized by trisomy 21 and is a leading cause of intellectual disability worldwide. The prevalence of DS is commonly associated with advanced maternal age and is associated with multiple comorbid conditions. The current study aimed to investigate the frequency of and relationship between sleep problems, gastrointestinal symptoms, comorbid psychopathology, and challenging behavior in children and adolescents with DS. High-frequency levels were found for sleep problems (100 %), challenging behavior (100 %), gastrointestinal symptoms (74.8 %), and moderate to severe levels of the different comorbid psychopathologies (tantrum=80 %; repetitive behavior=63 %; avoidant behavior=82 %; worry/depressed=61 %; conduct behavior=100 %; over-eating=100 %; under-eating=100 %). Results indicated a significant difference in self-injurious behavior frequency between individuals who presented with abdominal pain and those who did not. This study is the first to investigate the relationship of multiple comorbid conditions in a sample of children with DS. This paper adds to the literature by demonstrating the frequency of a number of comorbid conditions in children and adolescents with DS. The paper also adds novel findings to the literature by investigating the relationships between comorbid conditions in this population. The findings of this paper highlighted the frequency and comorbidities that exist between gastrointestinal symptoms, sleep problems, comorbid psychopathology, and challenging behavior. Analyses indicated that those who presented with abdominal pain, engaged in self-injurious behavior more frequently. Sleep problems, gastrointestinal symptoms, comorbid psychopathology, and challenging behavior in children and adolescents with Down Syndrome.

The high cost of care and limited evidence on cost-effective strategies for Lewy body dementia: systematic review of evidence.

BACKGROUND: Lewy body dementia (LBD) is a prevalent yet frequently underdiagnosed form of dementia, accounting for up to 15% of all dementia cases. AIMS: This study aims to increase awareness and advocacy for LBD by gathering and critically assessing the economic evidence, including the cost of illness and cost-effectiveness of interventions for managing LBD. METHOD: A systematic literature review was undertaken with EMBASE, Medline, CINAHL, PsycINFO, NHS Economic Evaluation Database and EconLit. This search was supplemented by grey literature on Google Scholar and reviewing the reference lists of identified studies. The papers included in the review were published between 2008 and 2023, and involved participants with LBD (dementia with Lewy bodies or Parkinson's disease dementia), which either addressed the cost of illness or conducted an economic evaluation. RESULTS: Thirteen papers were included, comprising ten cost-of-illness studies and three economic evaluations. The cost of LBD tends to be higher than that of other forms of dementia, such as Alzheimer's disease, and these costs escalate more steeply as the disease progresses. These cost differences may not be solely influenced by the subtype of dementia, but possibly also by patient characteristics like physical and cognitive abilities. Cost-effectiveness of potential interventions for LBD is limited. CONCLUSIONS: Despite numerous drug trials and other interventions for dementia, very few have targeted LBD, let alone explored the cost-effectiveness of such therapies for LBD. This disparity highlights the urgent need for cost-effective strategies and interventions targeting LBD. We propose the establishment of universally accepted standards for LBD research.

A novel method for the percutaneous induction of myocardial infarction by occlusion of small coronary arteries in the rabbit.

Arrhythmic sudden cardiac death (SCD) is an important cause of mortality following myocardial infarction (MI). The rabbit has similar cardiac electrophysiology to humans and is therefore an important small animal model to study post-MI arrhythmias. The established approach of surgical coronary ligation results in thoracic adhesions that impede epicardial electrophysiological studies. Adhesions are absent following a percutaneously induced MI, which is also associated with reduced surgical morbidity and so represents a clear refinement of the approach. Percutaneous procedures have previously been described in large rabbits (3.5-5.5 kg). Here, we describe a novel method of percutaneous MI induction in smaller rabbits (2.5-3.5 kg) that are readily available commercially. New Zealand White rabbits (n = 51 males, 3.1 ± 0.3 kg) were anesthetized using isoflurane (1.5-3%) and underwent either a percutaneous MI procedure involving microcatheter tip deployment (≤1.5 Fr, 5 mm), coronary ligation surgery, or a sham procedure. Electrocardiography (ECG) recordings were used to confirm ST-segment elevation indicating coronary occlusion. Blood samples (1 and 24 h) were taken for cardiac troponin I (cTnI) levels. Ejection fraction (EF) was measured at 6-8 wk. Rabbits were then euthanized (Euthatal) and hearts were processed for magnetic resonance imaging and histology. Mortality rates were similar in both groups. Scar volume, cTnI, and EF were similar between both MI groups and significantly different from their respective sham controls. Thus, percutaneous coronary occlusion by microcatheter tip deployment is feasible in rabbits (2.5-3.5 kg) and produces an MI with similar characteristics to surgical ligation with lower procedural trauma and without epicardial adhesions.NEW & NOTEWORTHY Surgical coronary ligation is the standard technique to induce myocardial infarction (MI) in rabbits but is associated with procedural trauma and the generation of thoracic adhesions. Percutaneous coronary occlusion avoids these shortcomings and is established in pigs but has only been applicable to large rabbits because of a mismatch between the equipment used and target vessel size. Here, we describe a new scalable approach to percutaneous MI induction that is safe and effective in 2.5-3.5-kg rabbits.

A novel binary pesticidal protein from Chryseobacterium arthrosphaerae controls western corn rootworm by a different mode of action to existing commercial pesticidal proteins.

The western corn rootworm (WCR) Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae) remains one of the economically most important pests of maize (Zea mays) due to its adaptive capabilities to pest management options. This includes the ability to develop resistance to some of the commercial pesticidal proteins originating from different strains of Bacillus thuringiensis. Although urgently needed, the discovery of new, environmentally safe agents with new modes of action is a challenge. In this study we report the discovery of a new family of binary pesticidal proteins isolated from several Chryseobacterium species. These novel binary proteins, referred to as GDI0005A and GDI0006A, produced as recombinant proteins, prevent growth and increase mortality of WCR larvae, as does the bacteria. These effects were found both in susceptible and resistant WCR colonies to Cry3Bb1 and Cry34Ab1/Cry35Ab1 (reassigned Gpp34Ab1/Tpp35Ab1). This suggests GDI0005A and GDI0006A may not share the same binding sites as those commercially deployed proteins and thereby possess a new mode of action. This paves the way towards the development of novel biological or biotechnological management solutions urgently needed against rootworms.

The role of basement membranes in cardiac biology and disease.

Basement membranes (BMs) are highly specialised extracellular matrix (ECM) structures that within the heart underlie endothelial cells (ECs) and surround cardiomyocytes and vascular smooth muscle cells. They generate a dynamic and structurally supportive environment throughout cardiac development and maturation by providing physical anchorage to the underlying interstitium, structural support to the tissue, and by influencing cell behaviour and signalling. While this provides a strong link between BM dysfunction and cardiac disease, the role of the BM in cardiac biology remains under-researched and our understanding regarding the mechanistic interplay between BM defects and their morphological and functional consequences remain important knowledge-gaps. In this review, we bring together emerging understanding of BM defects within the heart including in common cardiovascular pathologies such as contractile dysfunction and highlight some key questions that are now ready to be addressed.

Defining treatment-resistant depression.

BACKGROUND: Varying conceptualizations of treatment-resistant depression (TRD) have made translating research findings or systematic reviews into clinical practice guidelines challenging and inconsistent. METHODS: We conducted a review for the Centers for Medicare & Medicaid Services and the Agency for Healthcare Research and Quality to clarify how experts and investigators have defined TRD and to review systematically how well this definition comports with TRD definitions in clinical trials through July 5, 2019. RESULTS: We found that no consensus definition existed for TRD. The most common TRD definition for major depressive disorder required a minimum of two prior treatment failures and confirmation of prior adequate dose and duration. The most common TRD definition for bipolar disorder required one prior treatment failure. No clear consensus emerged on defining adequacy of either dose or duration. Our systematic review found that only 17% of intervention studies enrolled samples meeting the most frequently specified criteria for TRD. Depressive outcomes and clinical global impressions were commonly measured; functional impairment and quality-of-life tools were rarely used. CONCLUSIONS: Two key steps are critical to advancing TRD research: (a) Developing a consensus definition of TRD that addresses how best to specify the number of prior treatment failures and the adequacy of dose and duration; and (b) identifying a core package of outcome measures that can be applied in a standardized manner. Our recommendations about stronger approaches to designing and conducting TRD research will foster better evidence to translate into clearer guidelines for treating patients with this serious condition.

Mice Lacking Alternatively Activated (M2) Macrophages Show Impairments in Restorative Sleep after Sleep Loss and in Cold Environment.

The relationship between sleep, metabolism and immune functions has been described, but the cellular components of the interaction are incompletely identified. We previously reported that systemic macrophage depletion results in sleep impairment after sleep loss and in cold environment. These findings point to the role of macrophage-derived signals in maintaining normal sleep. Macrophages exist either in resting form, classically activated, pro-inflammatory (M1) or alternatively activated, anti-inflammatory (M2) phenotypes. In the present study we determined the contribution of M2 macrophages to sleep signaling by using IL-4 receptor α-chain-deficient [IL-4Rα knockout (KO)] mice, which are unable to produce M2 macrophages. Sleep deprivation induced robust increases in non-rapid-eye-movement sleep (NREMS) and slow-wave activity in wild-type (WT) animals. NREMS rebound after sleep deprivation was ~50% less in IL-4Rα KO mice. Cold exposure induced reductions in rapid-eye-movement sleep (REMS) and NREMS in both WT and KO mice. These differences were augmented in IL-4Rα KO mice, which lost ~100% more NREMS and ~25% more REMS compared to WTs. Our finding that M2 macrophage-deficient mice have the same sleep phenotype as mice with global macrophage depletion reconfirms the significance of macrophages in sleep regulation and suggests that the main contributors are the alternatively activated M2 cells.

Hormone Therapy for the Primary Prevention of Chronic Conditions in Postmenopausal Women: Evidence Report and Systematic Review for the US Preventive Services Task Force.

Importance: Postmenopausal status coincides with increased risks for chronic conditions such as heart disease, osteoporosis, cognitive impairment, or some types of cancers. Previously, hormone therapy was used for the primary prevention of these chronic conditions. Objective: To update evidence for the US Preventive Services Task Force on the benefits and harms of hormone therapy in reducing risks for chronic conditions. Data Sources: MEDLINE, Cochrane Library, EMBASE, and trial registries from June 1, 2011, through August 1, 2016. Surveillance for new evidence in targeted publications was conducted through July 1, 2017. Study Selection: English-language randomized clinical trials reporting health outcomes. Data Extraction and Synthesis: Dual review of abstracts, full-text articles, and study quality; meta-analyses when at least 3 similar studies were available. Main Outcomes and Measures: Beneficial or harmful changes in risks for various chronic conditions. Results: Eighteen trials (n = 40 058; range, 142-16 608; mean age, 53-79 years) were included. Women using estrogen-only therapy compared with placebo had significantly lower risks, per 10 000 person-years, for diabetes (-19 cases [95% CI, -34 to -3]) and fractures (-53 cases [95% CI, -69 to -39]). Risks were statistically significantly increased, per 10 000 person-years, for gallbladder disease (30 more cases [95% CI, 16 to 48]), stroke (11 more cases [95% CI, 2 to 23]), venous thromboembolism (11 more cases [95% CI, 3 to 22]), and urinary incontinence (1261 more cases [95% CI, 880 to 1689]). Women using estrogen plus progestin compared with placebo experienced significantly lower risks, per 10 000 person-years, for colorectal cancer (-6 cases [95% CI, -9 to -1]), diabetes (-14 cases [95% CI, -24 to -3), and fractures (-44 cases [95% CI, -71 to -13). Risks, per 10 000 person-years, were significantly increased for invasive breast cancer (9 more cases [95% CI, 1 to 19]), probable dementia (22 more cases [95% CI, 4 to 53]), gallbladder disease (21 more cases [95% CI, 10 to 34]), stroke (9 more cases [95% CI, 2 to 19]), urinary incontinence (876 more cases [95% CI, 606 to 1168]), and venous thromboembolism (21 more cases [95% CI, 12 to 33]). Conclusions and Relevance: Hormone therapy for the primary prevention of chronic conditions in menopausal women is associated with some beneficial effects but also with a substantial increase of risks for harms. The available evidence regarding benefits and harms of early initiation of hormone therapy is inconclusive.

Comparative Benefits and Harms of Complementary and Alternative Medicine Therapies for Initial Treatment of Major Depressive Disorder: Systematic Review and Meta-Analysis.

OBJECTIVES: To report the comparative benefits and harms of exercise and complementary and alternative medicine (CAM) treatments with second-generation antidepressants (SGA) for major depressive disorder (MDD). DESIGN: Systematic review and meta-analysis. SETTINGS: Outpatient clinics. SUBJECTS: Adults, aged 18 years and older, with MDD receiving an initial treatment attempt with SGA. INTERVENTIONS: Any CAM or exercise intervention compared with an SGA. OUTCOME MEASURES: Treatment response, remission, change in depression rating, adverse events, treatment discontinuation, and treatment discontinuation due to adverse events. RESULTS: We found 22 randomized controlled trials for direct comparisons and 127 trials for network meta-analyses, including trials of acupuncture, omega-3 fatty acids, S-adenosyl methionine, St. John's wort, and exercise. For most treatment comparisons, we found no differences between treatment groups for response and remission. However, the risk of bias of these studies led us to conclude that the strength of evidence for these findings was either low or insufficient. The risk of treatment harms and treatment discontinuation attributed to adverse events was higher for selective serotonin receptor inhibitors than for St. John's wort. CONCLUSIONS: Although we found little difference in the comparative efficacy of most CAM therapies or exercise and SGAs, the overall poor quality of the available evidence base tempers any conclusions that we might draw from those trials. Future trials should incorporate patient-oriented outcomes, treatment expectancy, depressive severity, and harms assessments into their designs; antidepressants should be administered over their full dosage ranges; and larger trials using methods to reduce sampling bias are needed.

Primary Care Screening and Treatment for Latent Tuberculosis Infection in Adults: Evidence Report and Systematic Review for the US Preventive Services Task Force.

IMPORTANCE: Five to ten percent of individuals with latent tuberculosis infection (LTBI) progress to active tuberculosis (TB) disease. Identifying and treating LTBI is a key component of the strategy for reducing the burden of TB disease. OBJECTIVE: To review the evidence about targeted screening and treatment for LTBI among adults in primary care settings to support the US Preventive Services Task Force in updating its 1996 recommendation. DATA SOURCES: MEDLINE, Cochrane Library, and trial registries, searched through August 3, 2015; references from pertinent articles; and experts. Literature surveillance was conducted through May 31, 2016. STUDY SELECTION: English-language studies of LTBI screening, LTBI treatment with recommended pharmacotherapy, or accuracy of the tuberculin skin test (TST) or interferon-gamma release assays (IGRAs). Studies of individuals for whom LTBI screening and treatment is part of public health surveillance or disease management were excluded. DATA EXTRACTION AND SYNTHESIS: Two investigators independently reviewed abstracts and full-text articles. When at least 3 similar studies were available, random-effects meta-analysis was used to generate pooled estimates of outcomes. MAIN OUTCOMES AND MEASURES: Sensitivity, specificity, reliability, active TB disease, mortality, hepatotoxicity, and other harms. RESULTS: The review included 72 studies (n = 51 711). No studies evaluated benefits and harms of screening compared with no screening. Pooled estimates for sensitivity of the TST at both 5-mm and 10-mm induration thresholds were 0.79 (5-mm: 95% CI, 0.69-0.89 [8 studies, n = 803]; 10 mm: 95% CI, 0.71-0.87 [11 studies; n = 988]), and those for IGRAs ranged from 0.77 to 0.90 (57 studies; n = 4378). Pooled estimates for specificity of the TST at the 10-mm and 15-mm thresholds and for IGRAs ranged from 0.95 to 0.99 (34 studies; n = 23 853). A randomized clinical trial (RCT) of 24 weeks of isoniazid in individuals with pulmonary fibrotic lesions and LTBI (n = 27 830) found a reduction in absolute risk of active TB at 5 years from 1.4% to 0.5% (relative risk [RR], 0.35 [95% CI, 0.24-0.52]) and an increase in absolute risk for hepatoxicity from 0.1% to 0.5% (RR, 4.59 [95% CI, 2.03-10.39]) for 24 weeks of daily isoniazid compared with placebo. An RCT (n = 6886) found that 3 months of once-weekly rifapentine plus isoniazid was noninferior to 9 months of isoniazid alone for preventing active TB. The risk difference for hepatoxicity comparing isoniazid with rifampin ranged from 3% to 7%, with a pooled RR of 3.29 (95% CI, 1.72-6.28 [3 RCTs; n = 1327]). CONCLUSIONS AND RELEVANCE: No studies evaluated the benefits and harms of screening compared with no screening. Both the TST and IGRAs are moderately sensitive and highly specific within countries with low TB burden. Treatment reduced the risk of active TB among the populations included in this review. Isoniazid is associated with higher rates of hepatotoxicity than placebo or rifampin.

Effects of Macrophage Depletion on Sleep in Mice.

The reciprocal interaction between the immune system and sleep regulation has been widely acknowledged but the cellular mechanisms that underpin this interaction are not completely understood. In the present study, we investigated the role of macrophages in sleep loss- and cold exposure-induced sleep and body temperature responses. Macrophage apoptosis was induced in mice by systemic injection of clodronate-containing liposomes (CCL). We report that CCL treatment induced an immediate and transient increase in non-rapid-eye movement sleep (NREMS) and fever accompanied by decrease in rapid-eye movement sleep, motor activity and NREMS delta power. Chronically macrophage-depleted mice had attenuated NREMS rebound after sleep deprivation compared to normal mice. Cold-induced increase in wakefulness and decrease in NREMS, rapid-eye movement sleep and body temperature were significantly enhanced in macrophage-depleted mice indicating increased cold sensitivity. These findings provide further evidence for the reciprocal interaction among the immune system, sleep and metabolism, and identify macrophages as one of the key cellular elements in this interplay.

Comparative Benefits and Harms of Antidepressant, Psychological, Complementary, and Exercise Treatments for Major Depression: An Evidence Report for a Clinical Practice Guideline From the American College of Physicians.

BACKGROUND: Primary care patients and clinicians may prefer options other than second-generation antidepressants for the treatment of major depressive disorder (MDD). The comparative benefits and harms of antidepressants and alternative treatments are unclear. PURPOSE: To compare the benefits and harms of second-generation antidepressants and psychological, complementary and alternative medicine (CAM), and exercise treatments as first- and second-step interventions for adults with acute MDD. DATA SOURCES: English-, German-, and Italian-language studies from multiple electronic databases (January 1990 to September 2015); trial registries and gray-literature databases were used to identify unpublished research. STUDY SELECTION: Two investigators independently selected comparative randomized trials of at least 6 weeks' duration on health outcomes of adult outpatients; nonrandomized studies were eligible for harms. DATA EXTRACTION: Reviewers abstracted data on study design, participants, interventions, and outcomes; rated the risk of bias; and graded the strength of evidence. A senior reviewer confirmed data and ratings. DATA SYNTHESIS: 45 trials met inclusion criteria. On the basis of moderate-strength evidence, cognitive behavioral therapy (CBT) and antidepressants led to similar response rates (relative risk [RR], 0.90 [95% CI, 0.76 to 1.07]) and remission rates (RR, 0.98 [CI, 0.73 to 1.32]). In trials, antidepressants had higher risks for adverse events than most other treatment options; no information from nonrandomized studies was available. The evidence was too limited to make firm conclusions about differences in the benefits and harms of antidepressants compared with other treatment options as first-step therapies for acute MDD. For second-step therapies, different switching and augmentation strategies provided similar symptom relief. LIMITATION: High dropout rates, dosing inequalities, small sample sizes, and poor assessment of adverse events limit confidence in the evidence. CONCLUSION: Given their similar efficacy, CBT and antidepressants are both viable choices for initial treatment of MDD. PRIMARY FUNDING SOURCE: Agency for Healthcare Research and Quality.

Comparative benefits and harms of second generation antidepressants and cognitive behavioral therapies in initial treatment of major depressive disorder: systematic review and meta-analysis.

STUDY QUESTION: What are the benefits and harms of second generation antidepressants and cognitive behavioral therapies (CBTs) in the initial treatment of a current episode of major depressive disorder in adults? METHODS: This was a systematic review including qualitative assessment and meta-analyses using random and fixed effects models. Medline, Embase, the Cochrane Library, the Allied and Complementary Medicine Database, PsycINFO, and the Cumulative Index to Nursing and Allied Health Literature were searched from January 1990 through January 2015. The 11 randomized controlled trials included compared a second generation antidepressant CBT. Ten trials compared antidepressant monotherapy with CBT alone; three compared antidepressant monotherapy with antidepressant plus CBT. SUMMARY ANSWER AND LIMITATIONS: Meta-analyses found no statistically significant difference in effectiveness between second generation antidepressants and CBT for response (risk ratio 0.91, 0.77 to 1.07), remission (0.98, 0.73 to 1.32), or change in 17 item Hamilton Rating Scale for Depression score (weighted mean difference, -0.38, -2.87 to 2.10). Similarly, no significant differences were found in rates of overall study discontinuation (risk ratio 0.90, 0.49 to 1.65) or discontinuation attributable to lack of efficacy (0.40, 0.05 to 2.91). Although more patients treated with a second generation antidepressant than receiving CBT withdrew from studies because of adverse events, the difference was not statistically significant (risk ratio 3.29, 0.42 to 25.72). No conclusions could be drawn about other outcomes because of lack of evidence. Results should be interpreted cautiously given the low strength of evidence for most outcomes. The scope of this review was limited to trials that enrolled adult patients with major depressive disorder and compared a second generation antidepressant with CBT, and many of the included trials had methodological shortcomings that may limit confidence in some of the findings. WHAT THIS STUDY ADDS: Second generation antidepressants and CBT have evidence bases of benefits and harms in major depressive disorder. Available evidence suggests no difference in treatment effects of second generation antidepressants and CBT, either alone or in combination, although small numbers may preclude detection of small but clinically meaningful differences. Funding, competing interests, data sharing This project was funded under contract from the Agency for Healthcare Research and Quality by the RTI-UNC Evidence-based Practice Center. Detailed methods and additional information are available in the full report, available at http://effectivehealthcare.ahrq.gov/.

Prodrug applications for targeted cancer therapy.

Prodrugs are widely used in the targeted delivery of cytotoxic compounds to cancer cells. To date, targeted prodrugs for cancer therapy have achieved great diversity in terms of target selection, activation chemistry, as well as size and physicochemical nature of the prodrug. Macromolecular prodrugs such as antibody-drug conjugates, targeted polymer-drug conjugates and other conjugates that self-assemble to form liposomal and micellar nanoparticles currently represent a major trend in prodrug development for cancer therapy. In this review, we explore a unified view of cancer-targeted prodrugs and highlight several examples from recombinant technology that exemplify the prodrug concept but are not identified as such. Recombinant "prodrugs" such as engineered anthrax toxin show promise in biological specificity through the conditionally targeting of multiple cellular markers. Conditional targeting is achieved by structural complementation, the spontaneous assembly of engineered inactive subunits or fragments to reconstitute functional activity. These complementing systems can be readily adapted to achieve conditionally bispecific targeting of enzymes that are used to activate low-molecular weight prodrugs. By leveraging strengths from medicinal chemistry, polymer science, and recombinant technology, prodrugs are poised to remain a core component of highly focused and tailored strategies aimed at conditionally attacking complex molecular phenotypes in clinically relevant cancer.

Structural complementation of the catalytic domain of pseudomonas exotoxin A.

The catalytic moiety of Pseudomonas exotoxin A (domain III or PE3) inhibits protein synthesis by ADP-ribosylation of eukaryotic elongation factor 2. PE3 is widely used as a cytocidal payload in receptor-targeted protein toxin conjugates. We have designed and characterized catalytically inactive fragments of PE3 that are capable of structural complementation. We dissected PE3 at an extended loop and fused each fragment to one subunit of a heterospecific coiled coil. In vitro ADP-ribosylation and protein translation assays demonstrate that the resulting fusions-supplied exogenously as genetic elements or purified protein fragments-had no significant catalytic activity or effect on protein synthesis individually but, in combination, catalyzed the ADP-ribosylation of eukaryotic elongation factor 2 and inhibited protein synthesis. Although complementing PE3 fragments are catalytically less efficient than intact PE3 in cell-free systems, co-expression in live cells transfected with transgenes encoding the toxin fusions inhibits protein synthesis and causes cell death comparably as intact PE3. Complementation of split PE3 offers a direct extension of the immunotoxin approach to generate bispecific agents that may be useful to target complex phenotypes.

A molecular picture of motion in polyolefins.

We examined three united atom models in light of their description of polyolefin dynamics and investigated the relative influence of various potentials on the resulting dynamics. Results were compared with a collection of experimental data on polyethylene, poly(ethylene-alt-propylene), polypropylene, and head-to-head polypropylene, including quasielastic neutron scattering measurements that we report for two of these materials. For materials with branching, differences between force fields are apparent at low temperature, with the NERD force field most accurate. Differences between NERD and the others are the strength of nonbonded interactions and the height of torsional barriers. We artificially raised each, both of which leads to a slow down in dynamics similar to that observed when lowering temperature. Increasing nonbonded interaction strength slows dynamics with the Vogel dependence of the alpha-relaxation, while raising torsional barriers, slows dynamics with the Arrhenius dependence of the beta-relaxation.