The Chronic Kidney Disease in Children study is a cohort of about 600 children with chronic kidney disease (CKD) in the United States and Canada. The independent variable for our observations was a measurement of glomerular filtration rate (GFR) by iohexol disappearance (iGFR) at the first two visits one year apart and during alternate years thereafter. In a previous report, we had developed GFR estimating equations utilizing serum creatinine, blood urea nitrogen, height, gender and cystatin C measured by an immunoturbidimetric method; however the correlation coefficient of cystatin C and GFR (-0.69) was less robust than expected. Therefore, 495 samples were re-assayed using immunonephelometry. The reciprocal of immunonephelometric cystatin C was as well correlated with iGFR as was height/serum creatinine (both 0.88). We developed a new GFR estimating equation using a random 2/3 of 965 person-visits and applied it to the remaining 1/3 as a validation data set. In the validation data set, the correlation of the estimated GFR with iGFR was 0.92 with high precision and no bias; 91% and 45% of eGFR values were within 30% and 10% of iGFR, respectively. This equation works well in children with CKD in a range of GFR from 15 to 75 ml/min per 1.73 m2. Further studies are needed to establish the applicability to children of normal stature and muscle mass, and higher GFR.

Previous studies of the conditional ablation of TGF-β activated kinase 1 (TAK1) in mice indicate that TAK1 has an obligatory role in the survival and/or development of hematopoietic stem cells, B cells, T cells, hepatocytes, intestinal epithelial cells, keratinocytes, and various tissues, primarily because of these cells’ increased apoptotic sensitivity, and have implicated TAK1 as a critical regulator of the NF-κB and stress kinase pathways and thus a key intermediary in cellular survival. Contrary to this understanding of TAK1’s role, we report a mouse model in which TAK1 deletion in the myeloid compartment that evoked a clonal myelomonocytic cell expansion, splenomegaly, multi-organ infiltration, genomic instability, and aggressive, fatal myelomonocytic leukemia. Unlike in previous reports, simultaneous deletion of TNF receptor 1 (TNFR1) failed to rescue this severe phenotype. We found that the features of the disease in our mouse model resemble those of human chronic myelomonocytic leukemia (CMML) in its transformation to acute myeloid leukemia (AML). Consequently, we found TAK1 deletion in 13 of 30 AML patients (43%), thus providing direct genetic evidence of TAK1’s role in leukemogenesis.

Since stimulation of transient receptor potential channels of the vanilloid receptor subtype 1 (TRPV1) mitigates acute kidney injury (AKI) and endogenous N-acyl dopamine derivatives are able to activate TRPV1, we tested if synthetic N-octanoyl-dopamine (NOD) activates TRPV1 and if it improves AKI. These properties of NOD and its intrinsic anti-inflammatory character were compared with those of dopamine (DA). TRPV1 activation and anti-inflammatory properties of NOD and DA were tested using primary cell cultures in vitro. The influence of NOD and DA on AKI was tested in a prospective, randomized, controlled animal study with 42 inbred male Lewis rats (LEW, RT1), treated intravenously with equimolar concentrations of DA or NOD one hour before the onset of warm ischemia and immediately before clamp release. NOD, but not DA, activates TRPV1 channels in isolated dorsal root ganglion neurons (DRG) that innervate several tissues including kidney. In TNFα stimulated proximal tubular epithelial cells, inhibition of NFκB and subsequent inhibition of VCAM1 expression by NOD was significantly stronger than by DA. NOD improved renal function compared to DA and saline controls. Histology revealed protective effects of NOD on tubular epithelium at day 5 and a reduced number of monocytes in renal tissue of DA and NOD treated rats. Our data demonstrate that NOD but not DA activates TRPV1 and that NOD has superior anti-inflammatory properties in vitro. Although NOD mitigates deterioration in renal function after AKI, further studies are required to assess to what extend this is causally related to TRPV1 activation and/or desensitization.

Human pluripotent stem cell-derived cardiomyocytes (hPSC-CM) are being investigated as a new source of cardiac cells for drug safety assessment. We developed a novel scalable high content microscopy-based method for the detection of cell death in hPSC-CM that can serve for future predictive in vitro cardio-toxicological screens. Using rat neonatal ventricular cardiomyocytes (RVNC) or hPSC-CM, assays for nuclear remodelling, mitochondrial status, apoptosis and necrosis were designed using a combination of fluorescent dyes and antibodies on an automated microscopy platform. This allowed the observation of a chelerythrine-induced concentration-dependent apoptosis to necrosis switch and time-dependent progression of early apoptotic cells towards a necrotic-like phenotype. Susceptibility of hPSC-CM to chelerythrine-stimulated apoptosis varied with time after differentiation, but at most time points, hPSC-CM were more resistant than RVNC. This simple and scalable humanized high-content assay generates accurate cardiotoxicity profiles that can serve as a base for further assessment of cardioprotective strategies and drug safety.

Electronic supplementary material

The online version of this article (doi:10.1007/s12265-012-9396-1) contains supplementary material, which is available to authorized users.

Background

The prevalence, diagnostics and therapy of the burnout syndrome are increasingly discussed in the public. The unclear definition and diagnostics of the burnout syndrome are scientifically criticized. There are several therapies with unclear evidence for the treatment of burnout in existence.

Objectives

The health technology assessment (HTA) report deals with the question of usage and efficacy of different burnout therapies.

Methods

For the years 2006 to 2011, a systematic literature research was done in 31 electronic databases (e.g. EMBASE, MEDLINE, PsycINFO). Important inclusion criteria are burnout, therapeutic intervention and treatment outcome.

Results

17 studies meet the inclusion criteria and are regarded for the HTA report. The studies are very heterogeneous (sample size, type of intervention, measuring method, level of evidence). Due to their study design (e.g. four reviews, eight randomized controlled trials) the studies have a comparable high evidence: three times 1A, five times 1B, one time 2A, two times 2B and six times 4. 13 of the 17 studies are dealing with the efficacy of psychotherapy and psychosocial interventions for the reduction of burnout (partly in combination with other techniques). Cognitive behaviour therapy leads to the improvement of emotional exhaustion in the majority of the studies. The evidence is inconsistent for the efficacy of stress management and music therapy. Two studies regarding the efficacy of Qigong therapy do not deliver a distinct result. One study proves the efficacy of roots of Rhodiola rosea (evidence level 1B). Physical therapy is only in one study separately examined and does not show a better result than standard therapy.

Discussion

Despite the number of studies with high evidence the results for the efficacy of burnout therapies are preliminary and do have only limited reach. The authors of the studies complain about the low number of skilled studies for the therapy of burnout. Furthermore, they point to the insufficient evaluation of the therapy studies and the need for further research. Some authors report the effects of considerable natural recovering.

Numerous limitations affect the quality of the results. Intervention contents and duration, study design and study size are very diverse and do not permit direct comparison. Most of the samples are small by size with low statistical power, long-term follow-ups are missing. Comorbidities and parallel utilized therapies are insufficient documented or controlled. Most of the studies use the Maslach Burnout Inventory (MBI) as diagnostic or outcome-tool, but with different cut-off-points. It should be noticed that the validity of the MBI as diagnostic tool is not proved. Ethical, juridical and social determining factors are not covered or discussed in the studies.

Conclusion

The efficacy of therapies for the treatment of the burnout syndrome is insufficient investigated. Only for cognitive behavioural therapy (CBT) exists an adequate number of studies which prove its efficacy. Big long-term experimental studies are missing which compare the efficacy of the single therapies and evaluate their evidence. The natural recovering without any therapy needs further research. Additionally, it has to be examined to what extent therapies and their possible effects are thwarted by the conditions of the working place and the working conditions.

Hepatocellular carcinoma (HCC) is a leading cause of cancer mortality with nearly 700 000 deaths occurring annually. Hepatitis B virus (HBV) is a major contributor to HCC and acquired mutations in the HBV genome may accelerate its pathogenesis. In this study, a matched case–control investigation of 345 men who died of HCC and 625 controls were nested within a cohort of male hepatitis B surface antigen (HBsAg) carriers from Qidong, China. Matched preserving odds ratios (ORs) were used as a measure of association and 95% confidence intervals (CIs) as a measure of precision. Real-time polymerase chain reaction allowed for a quantitative comparison of the levels of the HBV 1762T/1764A mutation in cases and controls. A total of 278 (81%) of the cases were positive for the HBV 1762T/1764A mutation compared with 250 (40%) of the controls. The matched preserving OR of 6.72 (95% CI: 4.66 to 9.68) strongly indicated that cases were significantly more probably than controls to have the mutation. Plasma levels of DNA harboring the HBV mutation were on average 15-fold higher in cases compared with controls (P < 0.001). Most strikingly, the level of the mutation in the 20 controls who later developed and died of HCC were on average 274-fold higher than controls who did not develop HCC. Thus, within this cohort of HBsAg carriers at high risk of developing HCC, individuals positive for the HBV 1762T/1764A mutation at enrollment were substantially more probably to subsequently develop HCC, with a higher concentration of the mutation in plasma enhancing predisposition for cancer development.

Fibroblast growth factors 19 (FGF19) and 21 (FGF21) have emerged as key regulators of energy metabolism. Several studies have been conducted to understand the mechanism of FGF19 and FGF21 action, however, the data presented has often been inconsistent and at times contradictory. Here in a single study we compare the mechanisms mediating FGF19/FGF21 actions, and how similarities/differences in actions at the cellular level between these two factors translate to common/divergent physiological outputs. Firstly, we show that in cell culture FGF19/FGF21 are very similar, however, key differences are still observed differentiating the two. In vitro we found that both FGF's activate FGFRs in the context of βKlotho (KLB) expression. Furthermore, both factors alter ERK phosphorylation and glucose uptake with comparable potency. Combination treatment of cells with both factors did not have additive effects and treatment with a competitive inhibitor, the FGF21 delta N17 mutant, also blocked FGF19's effects, suggestive of a shared receptor activation mechanism. The key differences between FGF21/FGF19 were noted at the receptor interaction level, specifically the unique ability of FGF19 to bind/signal directly via FGFR4. To determine if differential effects on energy homeostasis and hepatic mitogenicity exist we treated DIO and ob/ob mice with FGF19/FGF21. We find comparable efficacy of the two proteins to correct body weight and serum glucose in both DIO and ob/ob mice. Nevertheless, FGF21 and FGF19 had distinctly different effects on proliferation in the liver. Interestingly, in vivo blockade of FGF21 signaling in mice using ΔN17 caused profound changes in glycemia indicative of the critical role KLB and FGF21 play in the regulation of glucose homeostasis. Overall, our data demonstrate that while subtle differences exist in vitro the metabolic effects in vivo of FGF19/FGF21 are indistinguishable, supporting a shared mechanism of action for these two hormones in the regulation of energy balance.

Short stem prostheses that preserve the femoral neck are becoming more and more popular. The CFP (collum femoris preserving) has been introduced especially for the treatment of younger patients. However, information about remodelling, complications and learning curve are thus far rare. We present a retrospective study of 155 patients (average age 59.3 ± 9.9 years) who underwent total hip replacement with the CFP prosthesis. Follow-up was obtained 74.3 ± 9.4 months postoperatively. The Harris hip score revealed excellent and good results in 96%. One stem had to be exchanged due to aseptic loosening revealing a survival rate of 99% and 100% for stem and cup, respectively. Radiological analysis showed typical patterns of remodelling with apearance of cortical thickening predominantly in the distal part of the prosthesis. Implant related revision rate was <1%, with further complication rate independent of the surgeon’s individual experience. With regard to outcome, survivorship and complication rate, the medium-term results of the CFP prosthesis are promising.

Beneficial effects of dietary phospholipids (PLs) have been mentioned since the early 1900's in relation to different illnesses and symptoms, e.g. coronary heart disease, inflammation or cancer. This article gives a summary of the most common therapeutic uses of dietary PLs to provide an overview of their approved and proposed benefits; and to identify further investigational needs.

From the majority of the studies it became evident that dietary PLs have a positive impact in several diseases, apparently without severe side effects. Furthermore, they were shown to reduce side effects of some drugs. Both effects can partially be explained by the fact that PL are highly effective in delivering their fatty acid (FA) residues for incorporation into the membranes of cells involved in different diseases, e.g. immune or cancer cells. The altered membrane composition is assumed to have effects on the activity of membrane proteins (e.g. receptors) by affecting the microstructure of membranes and, therefore, the characteristics of the cellular membrane, e.g. of lipid rafts, or by influencing the biosynthesis of FA derived lipid second messengers. However, since the FAs originally bound to the applied PLs are increased in the cellular membrane after their consumption or supplementation, the FA composition of the PL and thus the type of PL is crucial for its effect. Here, we have reviewed the effects of PL from soy, egg yolk, milk and marine sources. Most studies have been performed in vitro or in animals and only limited evidence is available for the benefit of PL supplementation in humans. More research is needed to understand the impact of PL supplementation and confirm its health benefits.

Hypersensitivity reactions against non-steroidal anti-inflammatory drugs (NSAIDs) like propyphenazone (PP) and diclofenac (DF) can manifest as Type I-like allergic reactions 1. In clinical practice, diagnosis of drug hypersensitivity is mainly performed by patient history, as skin testing is not reliable and oral provocation testing bears life-threatening risks for the patient 2. Hence, evidence for an underlying IgE-mediated pathomechanism is hard to obtain.

Here, we present an in vitro method based on the use of human basophils derived from drug-hypersensitive patients that mimics the allergic effector reaction in vivo. As basophils of drug-allergic patients carry IgE molecules specific for the culprit drug, they become activated upon IgE receptor crosslinking and release allergic effector molecules. The activation of basophils can be monitored by the determination of the upregulation of CD63 surface expression using flow cytometry 3.

In the case of low molecular weight drugs, conjugates are designed to enable IgE receptor crosslinking on basophils. As depicted in Figure 1, two representatives of NSAIDs, PP and DF, are covalently bound to human serum albumin (HSA) via a carboxyl group reacting with the primary amino group of lysine residues. DF carries an intrinsic carboxyl group and, thus, can be used directly 4, whereas a carboxyl group-containing derivative of PP had to be organochemically synthesized prior to the study 1.

The coupling degree of the low molecular weight compounds on the protein carrier molecule and their spatial distribution is important to guarantee crosslinking of two IgE receptor molecules. The here described protocol applies high performance-size exclusion chromatography (HPSEC) equipped with a sequential refractive index (RI) and ultra violet (UV) detection system for determination of the coupling degree.

As the described methodology may be applied for other drugs, the basophil activation test (BAT) bears the potential to be used for the determination of IgE-mediated mechanisms in drug hypersensitivity. Here, we determine PP hypersensitivity as IgE-mediated and DF hypersensitivity as non-IgE-mediated by BAT.

Background. Vaccination effectively prevents seasonal influenza. To promote vaccination adherence, it is necessary to understand the motivational process that underlies vaccination behavior. This was examined along with the moderating influence of past behavior on intention formation. Methods. German employees (N = 594) completed questionnaires at baseline and at 7-month followup. Regression analyses were conducted for mediation and moderated mediation. Results. Intention at Time 1 mediated the effect of risk perception, and positive and negative outcome expectancies on Time 2 vaccination. Past behavior moderated this effect: there was a mediation effect for risk perception and outcome expectancies only for those individuals who did not participate annually. Conclusions. Risk perception and outcome expectancies influenced intentions to receive vaccination, which in turn predicted participation. Hence, these social-cognitive variables could be targeted in vaccination campaigns to increase intentions. However, vaccination experience affected the formation of intentions and should be accounted for when developing interventions.

It is widely recognized that the dramatic increase in health care costs in the United States has not led to a corresponding improvement in the health care experience of patients or the clinical outcomes of medical care. In no area of medicine is this more true than in the area of spine related disorders (SRDs). Costs of medical care for SRDs have skyrocketed in recent years. Despite this, there is no evidence of improvement in the quality of this care. In fact, disability related to SRDs is on the rise. We argue that one of the key solutions to this is for the health care system to have a group of practitioners who are trained to function as primary care practitioners for the spine. We explain the reasons we think a primary spine care practitioner would be beneficial to patients, the health care system and society, some of the obstacles that will need to be overcome in establishing a primary spine care specialty and the ways in which these obstacles can be overcome.

Objective

This is an observational prospective cohort study to explore the treatment effect of mechanical vs. manual manipulation for acute low back pain.

Methods

Ninety two patients with a history of acute low back pain were recruited from 3 private chiropractic offices, 2 of which utilized manual lumbar manipulation and 1 used mechanical instrument manipulation (Activator) as their primary modes of treatment. The chiropractors used their “treatment as usual” protocols for a maximum of 8 visits or 4 weeks, which ever occurred first. Primary outcome measures were changes in Numeric Pain Rating Scale (NPRS) and Oswestry Disability Index (ODI) scores from baseline to 4 weeks. The linear regression models were adjusted for baseline NPRS and ODI scores, age, and treatment expectancy.

Results

Comparison of baseline characteristics did not show any significant differences between the groups except for age (38.4 vs. 49.7 years; p < .001) and treatment expectancy (5.7 vs. 6.3; p = .003). Linear regression revealed significantly lower NPRS scores in the manual manipulation group at four weeks [β = −1.2; 95% CI (−2.1, −.28)] but no significant difference in ODI scores between the two groups at four weeks [β = 1.5; 95% CI (−8.3, 2.4)]. Treatment expectancy, but not age, was found to have a significant main effect on both NPRS and ODI scores at 4 weeks. Exploratory analysis of the clinical patterns of care between the clinicians revealed significant differences in treatment frequency, duration, modality and radiograph usage between the 2 cohorts.

Conclusions

This study highlights the challenges inherent with conducting research that allows for “treatment-as-usual”. The data and experience derived from this investigational study will be used to design a future randomized clinical trial in which tighter controls will be imposed on the treatment protocol.

Background

Although symptoms of sleepiness and fatigue are common among adults with Chronic Kidney Disease (CKD), little is known about the prevalence of these symptoms in children with CKD.

Study Design

Cross-sectional analysis within a cohort study.

Setting & Participants

We describe the frequency and severity of sleep problems and fatigue, and we assess the extent of their association with measured glomerular filtration rate (mGFR) and Health-Related Quality of Life (HRQOL) among 301 participants of the Chronic Kidney Disease in Children cohort.

Outcomes and Measurements

Sleep and fatigue-related items from the Pediatric Quality of Life Inventory 4.0 Generic Scales and the CKD-related Symptoms List were used.

Results

Median mGFR was 42.0 ml/min/1.73m2 (25th–75th percentiles, 31.2–53.2) [EF1]and median age was 13.9 years (25th–75th percentiles, 10.8–16.2). Children with mGFR 40-<50, 30-<40, or <30 had 2.07 (95% CI, 1.05–4.09), 2.35 (95% CI 1.17, 4.72) and 2.59 (95% CI 1.15, 5.85) higher odds of having more severe parent reports of low energy than children with mGFR ≥50. Compared to participants with mGFR ≥50, those with mGFR <30 had 3.92 (95% CI 1.37, 11.17) higher odds of reporting more severe weakness, and those with mGFR 40-<50 had 2.95 (95% CI 1.26, 6.88) higher odds of falling asleep during the day. Low energy, trouble sleeping and weakness were associated with lower HRQOL scores.

Limitations

Symptoms of sleep and fatigue represent the child or parent’s perception of symptom severity, while individual items can lead to imprecise measurements of sleep and fatigue.

Conclusions

Lower mGFR was associated with increased weakness, low energy, and daytime sleepiness. Furthermore, a strong association between trouble sleeping, low energy and weakness with decrements in overall HRQOL was observed. Detection and treatment of poor sleep and fatigue may improve the development and HRQOL of children and adolescents with CKD.

Human embryonic stem cell-derived cardiomyocytes (hESC-CM) are being developed for tissue repair and as a model system for cardiac physiology and pathophysiology. However, the signaling requirements of their growth have not yet been fully characterized. We showed that hESC-CM retain their capacity for increase in size in long-term culture. Exposing hESC-CM to hypertrophic stimuli such as equiaxial cyclic stretch, angiotensin II, and phenylephrine (PE) increased cell size and volume, percentage of hESC-CM with organized sarcomeres, levels of ANF, and cytoskeletal assembly. PE effects on cell size were separable from those on cell cycle. Changes in cell size by PE were completely inhibited by p38–MAPK, calcineurin/FKBP, and mTOR blockers. p38–MAPK and calcineurin were also implicated in basal cell growth. Inhibitors of ERK, JNK, and CaMK II partially reduced PE effects; PKG or GSK3β inhibitors had no effect. The role of p38–MAPK was confirmed by an additional pharmacological inhibitor and adenoviral infection of hESC-CM with a dominant-inhibitory form of p38–MAPK. Infection of hESC-CM with constitutively active upstream MAP2K3b resulted in an increased cell size, sarcomere and cytoskeletal assembly, elongation of the cells, and induction of ANF mRNA levels. siRNA knockdown of p38–MAPK inhibited PE-induced effects on cell size. These results reveal an important role for active protein kinase signaling in hESC-CM growth and hypertrophy, with potential implications for hESC-CM as a novel in vitro test system. This article is part of a special issue entitled, "Cardiovascular Stem Cells Revisited".

Research Highlights

► Human embryonic stem cell-derived cardiomyocytes increase in size. ► Their growth is stimulated by classical physiological and pathological hypertrophic agents. ► A number of hypertrophic pathways act in this process, including p38–MAPK, calcineurin, FKBP, mTOR, HDAC II, ERK, JNK, and CAMK II. ► The regulation of cell growth and cell cycle progression are separable processes. ► The development of the cells can be a tool for the cardiac researcher or pharmaceutical industry.

Rationale

Germline ablation of the cytoskeletal protein nonmuscle myosin II-B (NMII-B) results in embryonic lethality with defects in both the brain and heart. Tissue specific ablation of NMII-B by a Cre-recombinase strategy should avoid embryonic lethality and permit study of the function of NMII-B in adult hearts.

Objective

To understand the function of NMII-B in adult mouse hearts and to see if the brain defects found in germline ablated mice influence cardiac development.

Methods and Results

We used a loxP/Cre-recombinase strategy to specifically ablate NMII-B in the brains or hearts of mice. Mice ablated for NMII-B in neural tissues, die between postnatal day 12 and 22 without showing cardiac defects. Mice deficient in NMII-B only in cardiac myocytes (BαMHC/BαMHC mice) do not show brain defects. However BαMHC/BαMHC mice display novel cardiac defects not seen in NMII-B germline ablated mice. Most of the BαMHC/BαMHC mice are born with enlarged cardiac myocytes some of which are multinucleated, reflecting a defect in cytokinesis. Between 6–10 months they develop a cardiomyopathy which includes interstitial fibrosis and infiltration of the myocardium and pericardium with inflammatory cells. Four of five BαMHC/BαMHC hearts develop marked widening of intercalated discs.

Conclusion

By avoiding the embryonic lethality found in germline-ablated mice we were able to study the function of NMII-B in adult mice and show that absence of NMII-B in cardiac myocytes results in cardiomyopathy in the adult heart. We also define a role for NMII-B in maintaining the integrity of intercalated discs.

Endocardial cushions are precursors of mature atrioventricular (AV) valves. Their formation is induced by signaling molecules originating from the AV myocardium, including bone morphogenetic proteins (BMPs). Here, we hypothesized that BMP signaling plays an important role in the AV myocardium during the maturation of AV valves from the cushions. To test our hypothesis, we used a unique Cre/lox system to target the deletion of a floxed Alk3 allele, the type IA receptor for BMPs, to cardiac myocytes of the AV canal (AVC). Lineage analysis indicated that cardiac myocytes of the AVC contributed to the tricuspid mural and posterior leaflets, the mitral septal leaflet, and the atrial border of the annulus fibrosus. When Alk3 was deleted in these cells, defects were seen in the same leaflets, ie, the tricuspid mural leaflet and mitral septal leaflet were longer, the tricuspid posterior leaflet was displaced and adherent to the ventricular wall, and the annulus fibrosus was disrupted resulting in ventricular preexcitation. The defects seen in mice with AVC-targeted deletion of Alk3 provide strong support for a role of Alk3 in human congenital heart diseases, such as Ebstein’s anomaly. In conclusion, our mouse model demonstrated critical roles for Alk3 signaling in the AV myocardium during the development of AV valves and the annulus fibrosus.

Certain protein-design calculations involve using an experimentally determined high-resolution structure as a template to identify new sequences that can adopt the same fold. This approach has led to the successful design of many novel, well-folded, native-like proteins. Although any atomic-resolution structure can serve as a template in such calculations, most successful designs have used high-resolution crystal structures. Because there are many proteins for which crystal structures are not available, it is of interest whether NMR templates are also appropriate. We have analyzed differences between using X-ray and NMR templates in side-chain repacking and design calculations. We assembled a database of 29 proteins for which both a high-resolution X-ray structure and an ensemble of NMR structures are available. Using these pairs, we compared the rotamericity, χ1-angle recovery and native-sequence recovery of X-ray and NMR templates. We carried out design using RosettaDesign on both types of templates, and compared the energies and packing qualities of the resulting structures. Overall, the X-ray structures were better templates for use with Rosetta. However, for ∼20% of proteins, a member of the reported NMR ensemble gave rise to designs with similar properties. Re-evaluating RosettaDesign structures with other energy functions indicated much smaller differences between the two types of templates. Ultimately, experiments are required to confirm the utility of particular X-ray and NMR templates. But our data suggest that the lack of a high-resolution X-ray structure should not preclude attempts at computational design if an NMR ensemble is available.

Background

The atrioventricular (AV) node is essential for the sequential excitation and optimized contraction of the adult multichambered heart; however, relatively little is known about its formation from the embryonic AV canal. A recent study demonstrated that signaling by Alk3, the type 1a receptor for bone morphogenetic proteins, in the myocardium of the AV canal was required for the development of both the AV valves and annulus fibrosus. To test the hypothesis that bone morphogenetic protein signaling also plays a role in AV node formation, we investigated conduction system function and AV node morphology in adult mice with conditional deletion of Alk3 in the AV canal.

Methods and Results

High-resolution optical mapping with correlative histological analysis of 28 mutant hearts revealed 4 basic phenotypic classes based on electrical activation patterns and volume-conducted ECGs. The frequency of AV node conduction and morphological abnormalities increased from no detectable anomalies (class I) to severe defects (class IV), which included the presence of bypass tracts, abnormal ventricular activation patterns, fibrosis of the AV node, and twin AV nodes.

Conclusion

The present findings demonstrate that bone morphogenetic protein signaling is required in the myocardium of the AV canal for proper AV junction development, including the AV node.

Objectives

To determine if a history of injection drug use influences genotypic PI resistance to antiretroviral agents..

Methods

We assessed the presence of resistance mutations in PI-naive injection drug users (IDUs) and non-IDUs participating in the Women’s Interagency HIV Study. Eighteen HIV-infected participants who reported injection drug use prior to study enrollment and 32 HIV-infected non-IDUs contributed a total of 34 and 65 person-visits, respectively to analyses.

Results

Based on data from multiple clones obtained from different time points from each individual we determined that primary PI resistance mutations were more frequent among person-visits contributed by IDUs (24%) than non-IDUs (8%, p=0.05). While neither reached statistical significance, diversity was higher within the protease region among study visits carrying PI resistant clones at both the nucleotide level (2.66 vs. 2.35; p=0.08) and at the amino acid level (1.60 vs. 1.32; p=0.23). Most of the primary resistance mutations could not be detected using the standard population sequencing employed in the clinical setting. Five of six individuals in whom clones encoding PI resistance mutations were identified failed PI-containing HAART within 12 months of therapy initiation.

Conclusions

Our findings indicate that more aggressive sampling for resistance mutations among viral clones prior to HAART initiation might permit selection of more effective treatment, particularly in IDUs.

Whether hepatitis C virus coinfection might accelerate atherosclerosis in HIV-infected individuals is unclear. We examined the relationship of HIV and hepatitis C virus with carotid artery intima media thickness and the presence of carotid plaques in the Women’s Interagency HIV Study. Hepatitis C virus infection was not associated with greater carotid artery intima media thickness after adjustment for demographic and traditional cardiovascular risk factors. Further follow-up is needed to clarify whether HIV/hepatitis C virus coinfection may be associated with a greater risk of carotid plaque.

Background

Evidence suggesting an increased risk of cardiovascular disease in HIV-infected individuals has heightened the need to understand the relation of HIV infection, antiretroviral therapy use, and non–HIV-related factors with insulin resistance (IR).

Methods

Prospective study of 1614 HIV-infected and 604 HIV-uninfected participants from the Women’s Interagency HIV Study between October 2000 and March 2007. Homeostasis model assessment (HOMA)–estimated IR at 11,019 semiannual visits.

Results

HIV-infected women reporting highly active antiretroviral therapy (HAART) had higher median HOMA than HIV-uninfected women {1.20 [95% confidence interval (CI): 1.11 to 1.30] times higher for those reporting protease inhibitor–containing HAART; 1.10 (95% CI: 1.01 to 1.20) times higher for those reporting non–protease inhibitor–containing HAART}. Among HIV-infected, cumulative exposure to nucleoside reverse transcriptase inhibitors (NRTIs) of >3 years was associated with HOMA 1.13 (95% CI: 1.02 to 1.25) times higher than the HOMA without any cumulative NRTI exposure. Cumulative exposure to the NRTI stavudine of >1 year was associated with HOMA 1.15 (95% CI: 1.05 to 1.27) times higher than the HOMA without any cumulative stavudine use. Family history of diabetes, hepatitis C virus seropositivity, higher body mass index, or reporting menopause was associated with higher HOMA.

Conclusions

Longer cumulative exposure to NRTI; in particular, stavudine is associated with greater IR in HIV-infected women.