Identification and assessment of the 1,6-dihydroxy-pyridin-2-one moiety as privileged scaffold for HBV ribonuclease H inhibition

The Hepatitis B Virus (HBV) ribonuclease H (RNase H) although promising remains an unexploited therapeutic target. HBV RNase H inhibition causes premature termination of viral minus-polarity DNA strands, prevents the synthesis of the viral positive-polarity DNA strand, and causes accumulation of RNA:DNA heteroduplexes within viral capsids. As part of our ongoing research to develop more potent anti-HBV RNase H inhibitors, we designed, synthesized and analyzed a library of 18 novel compounds (17 N-hydroyxpyridinedione (HPD) imine derivatives and 1 barbituric acid analogue) as potential leads for HBV treatment development. In cell assays, fourteen HPDs showed significant anti-HBV activity with EC50s from 1.1 to 2.5 μM and selectivity indices (SI) of up to 58. Three of them exhibited more than 3-fold improvement in the SI over the best previous HPD imine (SI = 13). To gain insight to the interaction between the tested compounds and the active site of HBV RNase H, docking experiments were undertaken. In almost all binding poses, the novel HPDs coordinated both active site Mg2+ ions via their oxygen trident. Furthermore, the novel HPDs displayed high cell permeability and solubility as well as good drug-like properties. These results reveal that HPD imines can be significantly active and selective HBV inhibitors, and that the HPD scaffold merits further development towards anti-HBV agents.

Repurposing N-hydroxy thienopyrimidine-2,4-diones (HtPD) as inhibitors of human cytomegalovirus pUL89 endonuclease: Synthesis and biological characterization

The terminase complex of human cytomegalovirus (HCMV) is required for viral genome packaging and cleavage. Critical to the terminase functions is a metal-dependent endonuclease at the C-terminus of pUL89 (pUL89-C). We have previously reported metal-chelating N-hydroxy thienopyrimidine-2,4-diones (HtPD) as inhibitors of human immunodeficiency virus 1 (HIV-1) RNase H. In the current work, we have synthesized new analogs and resynthesized known analogs of two isomeric HtPD subtypes, anti-HtPD (13), and syn-HtPD (14), and characterized them as inhibitors of pUL89-C. Remarkably, the vast majority of analogs strongly inhibited pUL89-C in the biochemical endonuclease assay, with IC50 values in the nM range. In the cell-based antiviral assay, a few analogs inhibited HCMV in low μM concentrations. Selected analogs were further characterized in a biophysical thermal shift assay (TSA) and in silico molecular docking, and the results support pUL89-C as the protein target of these inhibitors. Collectively, the biochemical, antiviral, biophysical, and in silico data reported herein indicate that the isomeric HtPD chemotypes 13-14 can serve as valuable chemical platforms for designing improved inhibitors of HCMV pUL89-C.

8-Hydroxy-1,6-naphthyridine-7-carboxamides as Inhibitors of Human Cytomegalovirus pUL89 Endonuclease

Human cytomegalovirus (HCMV) replication requires a metal-dependent endonuclease at the C-terminus of pUL89 (pUL89-C) for viral genome packaging and cleavage. We have previously shown that pUL89-C can be pharmacologically inhibited with designed metal-chelating compounds. We report herein the synthesis of a few 8-hydroxy-1,6-naphthyridine subtypes, including 5-chloro (subtype 15), 5-aryl (subtype 16), and 5-amino (subtype 17) variants. Analogs were studied for the inhibition of pUL89-C in a biochemical endonuclease assay, a biophysical thermal shift assay (TSA), in silico molecular docking, and for the antiviral potential against HCMV in cell-based assays. These studies identified eight analogs of 8-hydroxy-1,6-naphthyridine-7-carboxamide subtypes for further characterization, most of which inhibited pUL89-C with single-digit μM IC50 values, and conferred antiviral activity in μM range. TSA and molecular modeling of selected analogs corroborate their binding to pUL89-C. Collectively, our biochemical, antiviral, biophysical and in silico data suggest that 8-hydroxy-1,6-naphthyridine-7-carboxamide subtypes can be used for designing inhibitors of HCMV pUL89-C.

4,5-Dihydroxypyrimidine Methyl Carboxylates, Carboxylic Acids, and Carboxamides as Inhibitors of Human Cytomegalovirus pUL89 Endonuclease

Human cytomegalovirus (HCMV) terminase complex entails a metal-dependent endonuclease at the C-terminus of pUL89 (pUL89-C). We report herein the design, synthesis, and characterization of dihydroxypyrimidine (DHP) acid (14), methyl ester (13), and amide (15) subtypes as inhibitors of HCMV pUL89-C. All analogs synthesized were tested in an endonuclease assay and a thermal shift assay (TSA) and subjected to molecular docking to predict binding affinity. Although analogs inhibiting pUL89-C in the sub-μM range were identified from all three subtypes, acids (14) showed better overall potency, substantially larger thermal shift, and considerably better docking scores than esters (13) and amides (15). In the cell-based antiviral assay, six analogs inhibited HCMV with moderate activities (EC₅₀ = 14.4-22.8 μM). The acid subtype (14) showed good in vitro ADME properties, except for poor permeability. Overall, our data support the DHP acid subtype (14) as a valuable scaffold for developing antivirals targeting HCMV pUL89-C.

Discovery of N-benzyl hydroxypyridone carboxamides as a novel and potent antiviral chemotype against human cytomegalovirus (HCMV)

Current drugs for treating human cytomegalovirus (HCMV) infections are limited by resistance and treatment-associated toxicities. In developing mechanistically novel HCMV antivirals, we discovered an N-benzyl hydroxypyridone carboxamide antiviral hit (8a) inhibiting HCMV in submicromolar range. We describe herein the structure–activity relationship (SAR) for 8a, and the characterization of potent analogs for cytotoxicity/cytostatic property, the preliminary mechanism of action, and the absorption, distribution, metabolism and excretion (ADME) properties. The SAR revealed a few pharmacophore features conferring optimal antiviral profile, including the 5-OH, the N-1 benzyl, at least one –CH₂− in the linker, and a di-halogen substituted phenyl ring in the amide moiety. In the end, we identified numerous analogs with sub-micromolar antiviral potency and good selectivity index. The preliminary mechanism of action characterization used a pUL89-C biochemical endonuclease assay, a virus entry assay, a time-of-addition assay, and a compound withdrawal assay. ADME profiling measuring aqueous solubility, plasma and liver microsomal stability, and parallel artificial membrane permeability assay (PAMPA) permeability demonstrated largely favorable drug-like properties. Together, these studies validate the N-benzyl hydroxypyridone carboxamide as a viable chemotype for potent and mechanistically distinct antivirals against HCMV.

1393 The Impact of Using A Virtual Reality Surgical Curriculum to Train Scrub Practitioners in Complex Orthopaedic Surgery

Background

The training scrub practitioners receive varies considerably in comparison to their surgical counterpart, although their performance is key to a proficient surgical team. For infrequent procedures that require specific and often intricate equipment such as revision total knee arthroplasty (RTKA), their training may be limited to an initial guidance session by company representatives. This study aims to evaluate the impact of using a virtual reality (VR) curriculum to train scrub practitioners in the performance of a RTKA.

Method

Ten orthopaedic scrub practitioners were enrolled into VR training across four sessions. Each VR session consisted of training where participants were guided through the assembly of equipment and steps of the surgery. In the concluding three sessions, each training session was supplemented by an assessment session in VR without guidance. The outcomes measured in VR assessment were incorrect procedural sequence, duration of surgery and efficiency of movement. The transfer of skills outside VR were assessed pre-training and post-training by the participants performance in a sequence of tasks using real equipment.

Results

All participants enhanced their surgical performance in successive assessed VR sessions reducing their operative time by 47%, assistive prompts by 75% and dominant hand motion by 28%. Improvements in VR showed effective transfer when assessed using real equipment with participants achieving superior scores post-training (11.3% versus 83.5%).

Conclusions

VR enables safe learning and provides measurable feedback of procedural steps and technical skills of complex orthopaedic surgery. VR is an effective training tool for scrub practitioners, with transfer to the real world.

Synthetic Derivatives of Ciclopirox are Effective Inhibitors of Cryptococcus neoformans

Opportunistic fungal infections caused by Cryptococcus neoformans are a significant source of mortality in immunocompromised patients. They are challenging to treat because of a limited number of antifungal drugs, and novel and more effective anticryptococcal therapies are needed. Ciclopirox olamine, a N-hydroxypyridone, has been in use as an approved therapeutic agent for the treatment of topical fungal infections for more than two decades. It is a fungicide, with broad activity across multiple fungal species. We synthesized 10 N-hydroxypyridone derivatives to develop an initial structure-activity understanding relative to efficacy as a starting point for the development of systemic antifungals. We screened the derivatives for antifungal activity against C. neoformans and Cryptococcus gattii and counter-screened for specificity in Candida albicans and two Malassezia species. Eight of the ten show inhibition at 1-3 μM concentration (0.17-0.42 μg per mL) in both Cryptococcus species and in C. albicans, but poor activity in the Malassezia species. In C. neoformans, the N-hydroxypyridones are fungicides, are not antagonistic with either fluconazole or amphotericin B, and are synergistic with multiple inhibitors of the mitochondrial electron transport chain. They appear to function primarily by chelating iron within the active site of iron-dependent enzymes. This preliminary structure-activity relationship points to the need for a lipophilic functional group at position six of the N-hydroxypyridone ring and identifies positions four and six as sites where further substitution may be tolerated. These molecules provide a clear starting point for future optimization for efficacy and target identification.

A mid-throughput HBV replication inhibition assay capable of detecting ribonuclease H inhibitors

The hepatitis B virus (HBV) ribonuclease H (RNaseH) is a promising but unexploited drug target. Inhibiting the RNaseH blocks viral reverse transcription by truncating the minus-polarity DNA strand, causing accumulation of RNA:DNA heteroduplexes, and abrogating plus-polarity DNA synthesis. Screening for RNaseH inhibitors is complicated by the presence of the minus-polarity DNA strand even when replication is fully inhibited because this residual DNA can be detected by standard screening assays that measure reduction in total HBV DNA accumulation. We previously developed a strand-preferential qPCR assay that detects RNaseH replication inhibitors by measuring preferential suppression of the viral plus-polarity DNA strand. However, this assay employed cells grown in 6- or 12-well plates and hence was of very low throughput. Here, we adapted the assay to a 96-well format and conducted a proof-of-principle screen of 727 compounds. The newly developed assay is a valuable tool for anti-HBV drug discovery, particularly when screening for RNaseH inhibitors.

Should we routinely perform a post-operative hemoglobin check following unicompartmental knee arthroplasty?

OBJECTIVES

To study the significance of checking post-operative hemoglobin and hematocrit following unicompartmental knee arthroplasty (UKA).

SETTING

Single center. Multiple surgeons.

DESIGN

Retrospective case series. Level of evidence IV.

MATERIALS AND METHODS

Following institutional approval, a retrospective analysis of all patients undergoing UKA at our level one academic university hospital was conducted. Operative records of all patients undergoing primary UKA were reviewed between March 2016 and March 2019. Patients' pre-operative hemoglobin and hematocrit, BMI, co-morbidities, application of tourniquet, tourniquet time, administration of tranexamic acid, need for post-operative blood transfusion, hospital length of stay, complications, and re-admission were all recorded. Blood loss was estimated using the post-operative hematocrit.

RESULTS

A total number of 155 patients were included. There were 70 females (45%) and 85 males (55%). The mean age was 66 ± 10 years. Median pre-op blood volume was 4700 mLs (interquartile range (IQR); 4200-5100). Median blood loss was 600 mLs (IQR; 400-830). Mean pre-op hemoglobin was 135 ± 14 g/L and mean post-op hemoglobin was 122 ± 13 g/L. No patient had a post-op hemoglobin under 80 g/L (range 93-154). No patients in our study needed transfusion.

CONCLUSION

The results of our study indicated that post-operative hemoglobin and hematocrit check proved unnecessary in all of our patients and could have been omitted from post-operative routines. We conclude that routine post UKA check of hemoglobin and hematocrit can be avoided and be saved for special circumstances depending on patient's physiology.

Divergent synthesis of a thiolate-based α-hydroxytropolone library with a dynamic bioactivity profile

Here we describe a rapid and divergent synthetic route toward structurally novel αHTs functionalized with either one or two thioether or sulfonyl appendages. Evaluation of this library against hepatitis B and herpes simplex virus, as well as the pathogenic fungus Cryptococcus neoformans, and a human hepatoblastoma (HepDES19) revealed complementary biological profiles and new lead compounds with sub-micromolar activity against each pathogen.

Inhibition of HBV replication by N-hydroxyisoquinolinedione and N-hydroxypyridinedione ribonuclease H inhibitors

We recently developed a screening system capable of identifying and evaluating inhibitors of the Hepatitis B virus (HBV) ribonuclease H (RNaseH), which is the only HBV enzyme not targeted by current anti-HBV therapies. Inhibiting the HBV RNaseH blocks synthesis of the positive-polarity DNA strand, causing early termination of negative-polarity DNA synthesis and accumulation of RNA:DNA heteroduplexes. We previously reported inhibition of HBV replication by N-hydroxyisoquinolinediones (HID) and N-hydroxypyridinediones (HPD) in human hepatoma cells. Here, we report results from our ongoing efforts to develop more potent anti-HBV RNaseH inhibitors in the HID/HPD compound classes. We synthesized and screened additional HIDs and HPDs for preferential suppression of positive-polarity DNA in cells replicating HBV. Three of seven new HIDs inhibited HBV replication, however, the therapeutic indexes (TI = CC50/EC50) did not improve over what we previously reported. All nine of the HPDs inhibited HBV replication with EC50s ranging from 110 nM to 4 μM. Cellular cytotoxicity was evaluated by four assays and CC50s ranged from 15 to >100 μM. The best compounds have a calculated TI of >300, which is a 16-fold improvement over the primary HPD hit. These studies indicate that the HPD compound class holds potential for antiviral discovery.

Development and content validation of measures assessing adherence barriers and behaviors for use in clinical care

BACKGROUND

Providers are often unaware of poor adherence to prescribed medications for their patients with chronic diseases.

OBJECTIVE

To develop brief, computer-administered patient-reported measures in English and Spanish assessing adherence behaviors and barriers. Design, Participants, and Main Measures: Item pools were constructed from existing measures of medication adherence behaviors and barriers, which informed development of a patient concept elicitation interview guide to identify medication adherence behavior and barrier-related concepts. Two hundred six patients either living with HIV (PLWH) or without were interviewed. Interviews were coded, concepts matched to item pool content, and new items were developed for novel concepts. A provider/investigator team highlighted clinically relevant items. Cognitive interviews were conducted with patients on final candidate items (n = 37). The instruments were administered to 2081 PLWH.

KEY RESULTS

Behavioral themes from concept elicitation interviews included routines incorporating time of day, placement, visual cues, and intentionality to miss or skip doses. Barrier themes included health-related (e.g. depressed mood, feeling ill), attitudes/beliefs (e.g., need for medication), access (e.g., cost/insurance problems), and circumstantial barriers (e.g., lack of privacy, disruption of daily routine). The final instruments included 6 behavior items, and 1 barrier item with up to 23 response options. PLWH endorsed a mean (SD) of 3.5 (1.1) behaviors. The 201 PLWH who missed ≥2 doses in the previous week endorsed a mean (SD) of 3.1 (2.5) barriers. The intraclass correlation coefficient (ICC) for the numbers of behaviors endorsed in 61 PLWH after 4-16 days was 0.54 and for the number of barriers for the 20 PLWH with ≥2 missed doses the ICC was 0.89, representing fair and excellent test-retest reliability.

CONCLUSION

Measures of medication adherence behaviors and barriers were developed for use with patients living with chronic diseases focusing on clinical relevance, brevity, and content validity for use in clinical care.

Initial development and pilot testing of observer-reported outcomes (ObsROs) for children with cystic fibrosis ages 0-11years

PURPOSE

Patient-reported outcomes are important clinical trial endpoints. Young children may not be able to reliably report on how they feel or function, so observer-reported outcomes (ObsROs) may be more appropriate for them. The purpose of this study was to develop and pilot field test electronic parent-reported observational instruments for children with cystic fibrosis (CF) 0-6 and 7-11years of age.

METHODS

We performed concept elicitation interviews with parents of children with CF ≤11years of age to elicit the respiratory signs they could observe at baseline and during an acute respiratory illness. The resulting instruments were refined based on interviews with parents and clinicians. We conducted a pilot field test to evaluate test-retest reliability and the ability of items to distinguish well and sick periods.

RESULTS

The instruments consist of 17 items assessing respiratory signs and observable CF-related impacts. Test-retest reliability was acceptable for both age groups but discrimination was low for ages 7-11, likely reflecting less direct observation of older children by their parents.

CONCLUSIONS

An ObsRO for children with CF ages 0-6 appears promising, while self-report may be more appropriate for children >6years of age. Next steps for the 0-6year old instrument will be utilizing it as an exploratory endpoint in clinical trials to enable item reduction, scale development, and further reliability and validity testing. Ultimately, this ObsRO could be a promising endpoint for early intervention trials in young children with CF.

Medication understanding among patients living with multiple chronic conditions: Implications for patient-reported measures of adherence

BACKGROUND

Low health literacy is associated with poor medication adherence and poor health outcomes. Limited understanding of prescribed medications may decrease validity of patient-reported adherence measures.

OBJECTIVES

To assess knowledge of names and purposes of prescribed medications among patients with multiple chronic conditions.

METHODS

Individual interviews were conducted with a convenience sample of patients from six U.S. primary care clinics. Participants (n = 57) were English and/or Spanish-speaking patients prescribed 3+ medications for chronic conditions, for which non-adherence may lead to disability or death. In individual interviews, patients were asked to name their medications, explain the purpose of each, and to explain how they distinguish them from one another. Interviews were audio recorded, transcribed, and coded; coded content was quantified by 1) whether or not the patient could name medications; 2) method of categorizing medications; 3) whether or not the purpose of the medication was understood. Descriptive statistics were compiled using Fisher's exact test to determine the relationship between patient knowledge and medication characteristics.

RESULTS

Thirty percent of patients could not name at least one of their medications; 19% did not know their purpose; 30% held misconceptions about the purpose of one or more medications. There was no significant difference in ability to name medications or state their medication's purpose between patients using medi-sets, pre-packaged rolls, or blister packs, and patients who stored pills in their original containers (p = 0.56 and p = 0.73, respectively), or across demographic groups (p = 0.085 to 0.767).

CONCLUSIONS

Many patients demonstrated difficulty identifying the name and purpose of prescribed medications; this did not differ by demographic group or medication storage type. Patients may benefit from routine review of medications with their provider in order to improve health literacy, outcomes, and patient-reported adherence measurement.

Inhibition of hepatitis B virus replication by N-hydroxyisoquinolinediones and related polyoxygenated heterocycles

We previously reported low sensitivity of the hepatitis B virus (HBV) ribonuclease H (RNaseH) enzyme to inhibition by N-hydroxyisoquinolinedione (HID) compounds. Subsequently, our biochemical RNaseH assay was found to have a high false negative rate for predicting HBV replication inhibition, leading to underestimation of the number of HIDs that inhibit HBV replication. Here, 39 HID compounds and structurally related polyoxygenated heterocycles (POH), N-hydroxypyridinediones (HPD), and flutimides were screened for inhibition of HBV replication in vitro. Inhibiting the HBV RNaseH preferentially blocks synthesis of the positive-polarity DNA strand and causes accumulation of RNA:DNA heteroduplexes. Eleven HIDs and one HPD preferentially inhibited HBV positive-polarity DNA strand accumulation. EC₅₀s ranged from 0.69 μM to 19 μM with therapeutic indices from 2.4 to 71. Neither the HIDs nor the HPD had an effect on the ability of the polymerase to elongate DNA strands in capsids. HBV RNaseH inhibition by the HIDs was confirmed with an improved RNaseH assay and by detecting accumulation RNA:DNA heteroduplexes in HBV capsids from cells treated with a representative HID. Therefore, the HID scaffold is more promising for anti-HBV drug discovery than we originally reported, and the HPD scaffold may hold potential for antiviral development. The preliminary structure-activity relationship will guide optimization of the HID/HPDs as HBV inhibitors.

Hepatitis B virus genetic diversity has minimal impact on sensitivity of the viral ribonuclease H to inhibitors

Hepatitis B virus (HBV) causes hepatitis, cirrhosis, liver failure, and liver cancer, but the current therapies that employ either nucelos(t)ide analogs or (pegylated)interferon α do not clear the infection in the large majority of patients. Inhibitors of the HBV ribonuclease H (RNaseH) that are being developed with the goal of producing anti-HBV drugs are promising candidates for use in combination with the nucleos(t)ide analogs to improve therapeutic efficacy. HBV is genetically very diverse, with at least 8 genotypes that differ by ≥8% at the sequence level. This diversity is reflected in the viral RNaseH enzyme, raising the possibility that divergent HBV genotypes or isolates may have varying sensitivity to RNaseH inhibitors. To evaluate this possibility, we expressed and purified 18 patient-derived RNaseHs from genotypes B, C, and D. Basal RNaseH activity and sensitivity to three novel RNaseH inhibitors from three different chemotypes were assessed. We also evaluated four consensus HBV RNaseHs to determine if such sequences would be suitable for use in antiviral drug screening. The patient-derived enzymes varied by over 10-fold in their basal RNaseH activities, but they were equivalently sensitive to each of the three inhibitors. Similarly, all four consensus HBV RNaseH enzymes were active and were equally sensitive to an RNaseH inhibitor. These data indicate that a wide range of RNaseH sequences would be suitable for use in antiviral drug screening, and that genotype- or isolate-specific genetic variations are unlikely to present a barrier during antiviral drug development against the HBV RNaseH.

Systematic review: patient-reported outcome measures in coeliac disease for regulatory submissions

BACKGROUND

New therapeutics are moving into phase 3 clinical trials for the treatment of coeliac disease, a condition with no established therapies other than gluten-free diet. These trials will require a meaningful, validated and fit for purpose patient-reported outcome measure (PROM) to quantify the symptomatic improvement of patients.

AIM

To evaluate existing PROMs for suitability in a Food and Drug Administration (FDA) approval trial for a coeliac disease therapeutic.

METHOD

We performed a systematic search in five online databases (MedLine, EmBase, Web of Science, CENTRAL, CINAHL) for studies that enrolled patients with coeliac disease and used PROMs. Studies included in this review had to measure some PROM concept, be patient administered and based upon a previously validated instrument with published measurement properties.

RESULTS

Our literature search identified 2706 unique records of which 199 ultimately qualified for abstraction. The majority of PROMs used in studies of coeliac disease was generic and did not measure numerous symptoms or concerns of interest to patients. Four PROMs were found to contain appropriate content for use in an FDA trial: the coeliac disease-specific modification of the Gastrointestinal Symptoms Rating Scale (CeD-GSRS), Psychological General Well-Being Index (PGWB), the Celiac Disease Symptom Diary (CDSD) and the Celiac Disease Patient Reported Outcome (CeD-PRO). The GSRS and PGWB are most often used together and are two of the most extensively used measures in coeliac disease. The CDSD and CeD-PRO were developed exclusively for trials in coeliac disease but have much less published information on their measurement properties.

CONCLUSIONS

While we did not find PROMs that currently meet the stated expectations of the FDA for regulatory purposes, four PROMs (CeD-GSRS, PGWB, CDSD and CeD-PRO) appear to contain appropriate content and with modest additional validation work could meet scientific standards for valid and sensitive measures of disease and treatment outcome. Specifically, what is needed for these instruments is an understanding of how sensitive they are to real changes in-patient condition, how stable they are over a period of time when health status should not have changed (test-retest reliability) as well as how they correlate with other measures of patient functioning such as intestinal biopsy. All of these objectives could feasibly be accomplished over a short cohort study of patients with biopsy-defined coeliac disease undergoing gluten challenge.

Mode of communication, perceived level of understanding, and perceived quality of life in youth who are deaf or hard of hearing

Given the important role of parent-youth communication in adolescent well-being and quality of life, we sought to examine the relationship between specific communication variables and youth perceived quality of life in general and as a deaf or hard-of-hearing (DHH) individual. A convenience sample of 230 youth (mean age = 14.1, standard deviation = 2.2; 24% used sign only, 40% speech only, and 36% sign + speech) was surveyed on communication-related issues, generic and DHH-specific quality of life, and depression symptoms. Higher youth perception of their ability to understand parents' communication was significantly correlated with perceived quality of life as well as lower reported depressive symptoms and lower perceived stigma. Youth who use speech as their single mode of communication were more likely to report greater stigma associated with being DHH than youth who used both speech and sign. These findings demonstrate the importance of youths' perceptions of communication with their parents on generic and DHH-specific youth quality of life.

Weight loss and changes in generic and weight-specific quality of life in obese adolescents

PURPOSE

To investigate how weight loss correlates with changes in generic and weight-specific quality of life (QoL).

METHODS

Youth generic (YQOL-S) and weight-specific instruments (YQOL-W) from 133 youth age 11-19 were analyzed at the beginning and end of 4-week immersion camp sessions known to produce weight loss. Paired samples t tests were used to test mean difference between baseline and final Body Mass Index (BMI) and YQOL-S and YQOL-W scores. YQOL-S and YQOL-W scores were transformed to values between 0 and 100, with higher values indicating better QOL. Cohen's d effect sizes were calculated to assess magnitude of effects. Percent weight loss (as % of baseline weight), change in BMI (baseline kg/m²-follow-up kg/m²), and change in % overweight ((BMI-50th% BMI for age and sex)/50th% BMI for age and sex × 100) were calculated. Multiple regressions were used to model final YQOL scores in the 11-14 and 15-19 age groups as functions of each measure of weight change, sex, age, and baseline YQOL score.

RESULTS

Youth experienced significant reductions in BMI (Mean change = 3.7, SD = 1.4, t = 34.1, P < 0.001) and in the other measures of weight change. YQOL-S and YQOL-W scores improved significantly (P < 0.001), and effect sizes were 0.61 and 0.66, respectively.

CONCLUSION

Changes in generic and weight-specific quality of life scores are associated with weight loss. The weight-specific measure is slightly more sensitive to weight changes; however, when controlling for modifiers, the YQOL-W remained significantly associated with weight loss, while the generic QoL measure did not.

Patient-reported respiratory symptoms in cystic fibrosis

BACKGROUND

Cystic fibrosis (CF) specific patient-derived and reported symptom tools are critical steps toward evaluating the outcomes of new therapies for CF.

METHODS

We conducted 25 in-depth qualitative interviews using the Day Reconstruction Method and 9 cognitive interviews at two CF programs, the University of Washington and Seattle Children's Hospital and Regional Medical Center. The interviews were audio-recorded and transcribed, and then coded and analyzed for themes relating to pulmonary symptoms and related psychosocial impacts.

RESULTS

Six pulmonary symptoms were identified as central to CF: cough, sputum production, wheeze, chest tightness, difficulty breathing/shortness of breath, and fever. Emotional impacts included frustration, sadness/depression, irritability, worry, difficulty sleeping; while activity impacts included time spent sitting or lying down, reduction of usual activities, and missing school or work. In all, 8 symptom items, 4 emotional impacts items, and 4 activity impacts were selected for inclusion on a new daily diary. We also assessed triggers for seeking care.

CONCLUSIONS

Using a qualitative inductive methodology, we have obtained patient centered data regarding pulmonary symptoms and burdens and have created a novel patient reported outcome measure for CF. Future studies will assess the validity of the instruments.

Remote sensing-based predictors improve distribution models of rare, early successional and broadleaf tree species in Utah

Compared to bioclimatic variables, remote sensing predictors are rarely used for predictive species modelling. When used, the predictors represent typically habitat classifications or filters rather than gradual spectral, surface or biophysical properties. Consequently, the full potential of remotely sensed predictors for modelling the spatial distribution of species remains unexplored. Here we analysed the partial contributions of remotely sensed and climatic predictor sets to explain and predict the distribution of 19 tree species in Utah. We also tested how these partial contributions were related to characteristics such as successional types or species traits.We developed two spatial predictor sets of remotely sensed and topo-climatic variables to explain the distribution of tree species. We used variation partitioning techniques applied to generalized linear models to explore the combined and partial predictive powers of the two predictor sets. Non-parametric tests were used to explore the relationships between the partial model contributions of both predictor sets and species characteristics.More than 60% of the variation explained by the models represented contributions by one of the two partial predictor sets alone, with topo-climatic variables outperforming the remotely sensed predictors. However, the partial models derived from only remotely sensed predictors still provided high model accuracies, indicating a significant correlation between climate and remote sensing variables. The overall accuracy of the models was high, but small sample sizes had a strong effect on cross-validated accuracies for rare species.Models of early successional and broadleaf species benefited significantly more from adding remotely sensed predictors than did late seral and needleleaf species. The core-satellite species types differed significantly with respect to overall model accuracies. Models of satellite and urban species, both with low prevalence, benefited more from use of remotely sensed predictors than did the more frequent core species.Synthesis and applications. If carefully prepared, remotely sensed variables are useful additional predictors for the spatial distribution of trees. Major improvements resulted for deciduous, early successional, satellite and rare species. The ability to improve model accuracy for species having markedly different life history strategies is a crucial step for assessing effects of global change.

Quality of life and health-risk behaviors among adolescents

PURPOSE

To assess the association between health-risk behaviors and self-perceived quality of life among adolescents

METHODS

A sample of 2801 students (957 seventh and eighth graders and 1844 ninth through twelfth graders) completed the Teen Assessment Survey (TAP) and the surveillance module of the Youth Quality of Life Instrument (YQOL-S). TAP responses were used to determine health-risks related to tobacco use, alcohol use, illicit drug use, and high risk sexual behavior. Separate multivariate analyses of variance showed mean differences in contextual and perceptual items of the YQOL-S for each health-risk behavior. Differences among engagers (adolescents who often engage), experimenters (occasionally engage), and abstainers (never engage) in the health-risk behavior were evaluated by gender and junior/senior high school groups.

RESULTS

In general, adolescent abstainers reported higher quality of life (QoL) than engagers and experimenters on YQOL-S items. Adolescents who engaged in multiple risk behaviors scored even lower than those who engaged in only one health-risk behavior. Experimenters tended to rate their QoL more similar to that of abstainers than to that of engagers.

CONCLUSIONS

The framework of QoL proved useful in the evaluation of adolescents' engagement in health-risk behaviors. Additionally, assessing the areas of QoL that differ between the groups may provide information for planning interventions aimed at risk reduction among engagers and experimenters.

Abnormal cardiovascular responses to exercise during the development of obesity in dogs

This study examined the control of cardiovascular dynamics in response to exercise during the development of obesity in dogs. Left atrial pressure (LAP), mean arterial pressure, and cardiac output (CO) were determined both at rest and in response to treadmill exercise (5.6 km/h, 10% grade) first during a control, lean state and then, once a week while the dogs were maintained on a high fat diet (HFD) for 4 weeks. Body weight increased from 22.8 +/- 1.1 to 33.1 +/- 2.0 kg after 4 weeks of HFD. The dogs developed mild hypertension with increases in resting CO, heart rate, and LAP. The response to exercise was characterized by a decrease in LAP when the dogs were lean and, in contrast, by a dramatic increase in LAP during the development of obesity. In addition, after the third week, the dogs could no longer maintain exercise at the original level. These results suggest that abnormal left ventricular function may occur very early during the development of canine obesity.

Transcatheter occlusion of Blalock-Taussig shunts: technical options

PURPOSE

This review of findings in children undergoing transcatheter shunt occlusion was carried out to describe and compare the results of four different embolization techniques.

PATIENTS AND METHODS

A retrospective review of clinical, radiologic, and cardiac catheterization records was carried out for 18 consecutive pediatric patients referred for Blalock-Taussig shunt occlusion at one institution. Technical aspects included the use of three devices--steel wire/fiber coils, detachable latex balloons, and ductal occlusion devices--and four techniques--direct transarterial placement, transarterial placement with proximal or with distal flow control, and transvenous delivery.

RESULTS

Occlusion of the shunt was attempted in 17 patients (mean age, 6.2 years). Shunt occlusion was successful in 14 patients. Embolization of a device into the pulmonary circulation occurred in five patients, and was most frequent with transarterial delivery without flow control or with proximal flow control (in four of six). Transarterial occlusion with distal flow control and transvenous delivery of ductal occluder devices were the most reliable methods of occluding shunts without distal stenosis, with success in eight of nine cases with the former technique and all of three with the latter technique.

CONCLUSIONS

Transarterial embolization of Blalock-Taussig shunts carries a risk of device embolization to the pulmonary circulation; this is best avoided by the use of distal flow control or transvenous placement of a ductal occlusion device.

Sweet's syndrome with multifocal sterile osteomyelitis

Sweet's syndrome is a rare condition characterized by fever, leukocytosis, dense dermal infiltration of leukocytes, and painful indurated cutaneous plaques. We describe a 23-month-old male infant with the typical cutaneous manifestations of Sweet's syndrome and painful extremities that limited ambulation. Evaluation revealed multifocal sterile osteomyelitis of both tibia. After the institution of systemic corticosteroid therapy, the patient's symptoms resolved, and bone scans normalized. After one year of follow-up, the patient has intermittent recrudescences that resolve during corticosteroid therapy. Sterile multifocal osteomyelitis represents another clinical manifestation of Sweet's syndrome.

Xanthine dehydrogenase from Drosophila melanogaster: a comparison of the kinetic parameters of the pure enzyme from two wild-type isoalleles differing at a putative regulatory site

Xanthine dehydrogenase (XDH) from Drosophila melanogaster has been purified to homogeneity by immunoaffinity chromatography, and its kinetic parameters determined. Drosophila XDH exhibits ordered binding for substrate and NAD+, analogous to the corresponding enzymes from vertebrate sources. The wild-type enzyme exhibits a Km for xanthine of 2.4 X 10(-5) M, and for NAD+ of 4.0 X 10(-5) M. XDH purified from a genetic variant exhibiting elevated levels of enzyme activity has similar kinetic constants. The results provide further evidence that the site of variation in the latter strain results in higher steady state numbers of XDH molecules per fly.