Molecular docking, molecular dynamics simulations and binding free energy studies of interactions between Mycobacterium tuberculosis Pks13, PknG and bioactive constituents of extremophilic bacteria

Mycobacterial pathogens present a significant challenge to disease control efforts globally due to their inherent resistance to multiple antibiotics. The rise of drug-resistant strains of Mycobacterium tuberculosis has prompted an urgent need for innovative therapeutic solutions. One promising way to discover new tuberculosis drugs is by utilizing natural products from the vast biochemical space. Multidisciplinary methods can used to harness the bioactivity of these natural products. This study aimed to evaluate the antimycobacterial efficacy of functional crude extracts from bacteria isolated from gold mine tailings in South Africa. Bacterial strains were identified using 16S rRNA sequencing. The crude extracts obtained from the bacteria were tested against Mycobacterium tuberculosis H37Rv, Mycobacterium smegmatis mc2155, and Mycobacterium aurum A+. Untargeted HPLC-qTOF and molecular networking were used to identify the functional constituents present in extracts that exhibited inhibitory activity. A virtual screening workflow (VSW) was used to filter compounds that were strong binders to Mycobacterium tuberculosis Pks13 and PknG. The ligands returned from the VSW were subjected to optimization using density functional theory (DFT) at M06-2X/6-311++ (d,p) level of theory and basis set implemented in Gaussian16 Rev.C01. The optimized ligands were re-docked against Mycobacterium tuberculosis Pks13 and PknG. Molecular dynamics simulation and molecular mechanics generalized born surface area were used to evaluate the stability of the protein-ligand complexes formed by the identified hits. The hit that showed promising binding characteristics was virtually modified through multiple synthetic routes using reaction-driven enumeration. Three bacterial isolates showed significant activity against the two strains of Mycobacterium, while only two, Bacillus subtilis and Bacillus licheniformis, exhibited activity against both Mycobacterium tuberculosis H37Rv, Mycobacterium smegmatis mc2155, and Mycobacterium aurum A+. The tentatively identified compounds from the bacterial crude extracts belonged to various classes of natural compounds associated with antimicrobial activity. Two compounds, cyclo-(L-Pro-4-OH-L-Leu) and vazabitide A, showed strong binding against PknG and Pks13, with pre-MD MM-GBSA values of - 42.8 kcal/mol and - 47.6 kcal/mol, respectively. The DFT-optimized compounds exhibited the same docking scores as the ligands optimized using the OPSL-4 force field. After modifying vazabitide A, its affinity to the Pks13 binding site increased to - 85.8 kcal/mol, as revealed by the post-MD MM-GBSA analysis. This study highlights the potential of bacteria isolates from gold mine tailings as a source of new scaffolds for designing and optimizing anti-Mycobacterium agents. These agents synthesized in-silico can be further tested in-vitro to evaluate their efficacy.

Efficacies and ADME properties of redox active methylene blue and phenoxazine analogues for use in new antimalarial triple drug combinations with amino-artemisinins

Efforts to develop new artemisinin triple combination therapies effective against artemisinin-tolerant strains of Plasmodium falciparum based on rational combinations comprising artemisone or other amino-artemisinins, a redox active drug and a third drug with a different mode of action have now been extended to evaluation of three potential redox partners. These are the diethyl analogue AD01 of methylene blue (MB), the benzo [α]phenoxazine PhX6, and the thiosemicarbazone DpNEt. IC50 values in vitro against CQ-sensitive and resistant P. falciparum strains ranged from 11.9 nM for AD01-41.8 nM for PhX6. PhX6 possessed the most favourable pharmacokinetic (PK) profile: intrinsic clearance rate CLint was 21.47 ± 1.76 mL/min/kg, bioavailability was 60% and half-life was 7.96 h. AD01 presented weaker, but manageable pharmacokinetic properties with a rapid CLint of 74.41 ± 6.68 mL/min/kg leading to a half-life of 2.51 ± 0.07 h and bioavailability of 15%. DpNEt exhibited a half-life of 1.12 h and bioavailability of 8%, data which discourage its further examination, despite a low CLint of 10.20 mL/min/kg and a high Cmax of 6.32 µM. Efficacies of AD01 and PhX6 were enhanced synergistically when each was paired with artemisone against asexual blood stages of P. falciparum NF54 in vitro. The favourable pharmacokinetics of PhX6 indicate this is the best partner among the compounds examined thus far for artemisone. Future work will focus on extending the drug combination studies to artemiside in vitro, and conducting efficacy studies in vivo for artemisone with each of PhX6 and the related benzo[α]phenoxazine SSJ-183.

Tandem LC-MS Identification of Antitubercular Compounds in Zones of Growth Inhibition Produced by South African Filamentous Actinobacteria

Novel antitubercular compounds are urgently needed to combat drug-resistant Mycobacterium tuberculosis (Mtb). Filamentous actinobacteria have historically been an excellent source of antitubercular drugs. Despite this, drug discovery from these microorganisms has fallen out of favour due to the continual rediscovery of known compounds. To increase the chance of discovering novel antibiotics, biodiverse and rare strains should be prioritised. Subsequently, active samples need to be dereplicated as early as possible to focus efforts on truly novel compounds. In this study, 42 South African filamentous actinobacteria were screened for antimycobacterial activity using the agar overlay method against the Mtb indicator Mycolicibacterium aurum under six different nutrient growth conditions. Known compounds were subsequently identified through extraction and high-resolution mass spectrometric analysis of the zones of growth inhibition produced by active strains. This allowed the dereplication of 15 hits from six strains that were found to be producing puromycin, actinomycin D and valinomycin. The remaining active strains were grown in liquid cultures, extracted and submitted for screening against Mtb in vitro. Actinomadura napierensis B60^T was the most active sample and was selected for bioassay-guided purification. This resulted in the identification of tetromadurin, a known compound, but which we show for the first time to have potent antitubercular activity, with the MIC₉₀s within the range of 73.7-151.6 nM against M. tuberculosis H37Rv^Tin vitro under different test conditions. This shows that South African actinobacteria are a good source of novel antitubercular compounds and warrant further screening. It is also revealed that active hits can be dereplicated by HPLC-MS/MS analysis of the zones of growth inhibition produced by the agar overlay technique.

The evaluation of ADME and pharmacokinetic properties of decoquinate derivatives for the treatment of malaria

The emergence of Plasmodium falciparum (Pf) parasite strains tolerant of the artemisinin component and resistant to the other drug component in artemisinin combination therapies (ACTs) used for treatment now markedly complicates malaria control. Thus, development of new combination therapies are urgently required. For the non-artemisinin component, the quinolone ester decoquinate (DQ) that possesses potent activities against blood stage Pf and acts on a distinct target, namely the Pf cytochrome bc₁ complex, was first considered. However, DQ has poor drug properties including high lipophilicity and exceedingly poor aqueous solubility (0.06 μg/ml), rendering it difficult to administer. Thus, DQ was chemically modified to provide the secondary amide derivative RMB005 and the quinoline O-carbamate derivatives RMB059 and RMB060. The last possesses sub-nanomolar activities against multidrug resistant blood stages of Pf, and P. berghei sporozoite liver stages. Here we present the results of ADME analyses in vitro and pharmacokinetic analyses using C57BL/6 mice. The amide RMB005 had a maximum mean whole blood concentration of 0.49 ± 0.02 µM following oral administration; however, the area under the curve (AUC), elimination half-life (t_1/2) and bioavailability (BA) were not significantly better than those of DQ. Surprisingly, the quinoline O-carbamates which can be recrystallized without decomposition were rapidly converted into DQ in human plasma and blood samples. The maximum concentrations of DQ reached after oral administration of RMB059 and RMB060 were 0.23 ± 0.05 and 0.11 ± 0.01 µM, the DQ elimination half-lives were 4.79 ± 1.66 and 4.66 ± 1.16 h, and the DQ clearance were 19.40 ± 3.14 and 21.50 ± 3.38 respectively. Under these assay conditions, the BA of DQ could not be calculated Overall although RMB059 and -060 are labile in physiological medium with respect to the DQ parent, the potential to apply these as prodrugs is apparent from the current data coupled with their ease of preparation.

A Novel Ventilator Design for COVID-19 and Resource-Limited Settings

There has existed a severe ventilator deficit in much of the world for many years, due in part to the high cost and complexity of traditional ICU ventilators. This was highlighted and exacerbated by the emergence of the COVID-19 pandemic, during which the increase in ventilator production rapidly overran the global supply chains for components. In response, we propose a new approach to ventilator design that meets the performance requirements for COVID-19 patients, while using components that minimise interference with the existing ventilator supply chains. The majority of current ventilator designs use proportional valves and flow sensors, which remain in short supply over a year into the pandemic. In the proposed design, the core components are on-off valves. Unlike proportional valves, on-off valves are widely available, but accurate control of ventilation using on-off valves is not straightforward. Our proposed solution combines four on-off valves, a two-litre reservoir, an oxygen sensor and two pressure sensors. Benchtop testing of a prototype was performed with a commercially available flow analyser and test lungs. We investigated the accuracy and precision of the prototype using both compressed gas supplies and a portable oxygen concentrator, and demonstrated the long-term durability over 15 days. The precision and accuracy of ventilation parameters were within the ranges specified in international guidelines in all tests. A numerical model of the system was developed and validated against experimental data. The model was used to determine usable ranges of valve flow coefficients to increase supply chain flexibility. This new design provides the performance necessary for the majority of patients that require ventilation. Applications include COVID-19 as well as pneumonia, influenza, and tuberculosis, which remain major causes of mortality in low and middle income countries. The robustness, energy efficiency, ease of maintenance, price and availability of on-off valves are all advantageous over proportional valves. As a result, the proposed ventilator design will cost significantly less to manufacture and maintain than current market designs and has the potential to increase global ventilator availability.

Discovery of Novel Cyclic Ethers with Synergistic Antiplasmodial Activity in Combination with Valinomycin

With drug resistance threatening our first line antimalarial treatments, novel chemotherapeutics need to be developed. Ionophores have garnered interest as novel antimalarials due to their theorized ability to target unique systems found in the Plasmodium-infected erythrocyte. In this study, during the bioassay-guided fractionation of the crude extract of Streptomyces strain PR3, a group of cyclodepsipeptides, including valinomycin, and a novel class of cyclic ethers were identified and elucidated. Further study revealed that the ethers were cyclic polypropylene glycol (cPPG) oligomers that had leached into the bacterial culture from an extraction resin. Molecular dynamics analysis suggests that these ethers are able to bind cations such as K⁺, NH₄⁺ and Na⁺. Combination studies using the fixed ratio isobologram method revealed that the cPPGs synergistically improved the antiplasmodial activity of valinomycin and reduced its cytotoxicity in vitro. The IC₅₀ of valinomycin against P. falciparum NF54 improved by 4-5-fold when valinomycin was combined with the cPPGs. Precisely, it was improved from 3.75 ± 0.77 ng/mL to 0.90 ± 0.2 ng/mL and 0.75 ± 0.08 ng/mL when dosed in the fixed ratios of 3:2 and 2:3 of valinomycin to cPPGs, respectively. Each fixed ratio combination displayed cytotoxicity (IC₅₀) against the Chinese Hamster Ovary cell line of 57-65 µg/mL, which was lower than that of valinomycin (12.4 µg/mL). These results indicate that combinations with these novel ethers may be useful in repurposing valinomycin into a suitable and effective antimalarial.

The Critical Importance of Spatial and Temporal Scales in Designing and Interpreting Immune Cell Migration Assays

Intravital microscopy and other direct-imaging techniques have allowed for a characterisation of leukocyte migration that has revolutionised the field of immunology, resulting in an unprecedented understanding of the mechanisms of immune response and adaptive immunity. However, there is an assumption within the field that modern imaging techniques permit imaging parameters where the resulting cell track accurately captures a cell's motion. This notion is almost entirely untested, and the relationship between what could be observed at a given scale and the underlying cell behaviour is undefined. Insufficient spatial and temporal resolutions within migration assays can result in misrepresentation of important physiologic processes or cause subtle changes in critical cell behaviour to be missed. In this review, we contextualise how scale can affect the perceived migratory behaviour of cells, summarise the limited approaches to mitigate this effect, and establish the need for a widely implemented framework to account for scale and correct observations of cell motion. We then extend the concept of scale to new approaches that seek to bridge the current "black box" between single-cell behaviour and systemic response.

Toward New Transmission-Blocking Combination Therapies: Pharmacokinetics of 10-Amino-Artemisinins and 11-Aza-Artemisinin and Comparison with Dihydroartemisinin and Artemether

As artemisinin combination therapies (ACTs) are compromised by resistance, we are evaluating triple combination therapies (TACTs) comprising an amino-artemisinin, a redox drug, and a third drug with a different mode of action. Thus, here we briefly review efficacy data on artemisone, artemiside, other amino-artemisinins, and 11-aza-artemisinin and conduct absorption, distribution, and metabolism and excretion (ADME) profiling in vitro and pharmacokinetic (PK) profiling in vivo via intravenous (i.v.) and oral (p.o.) administration to mice. The sulfamide derivative has a notably long murine microsomal half-life (t1/2 > 150 min), low intrinsic liver clearance and total plasma clearance rates (CLint 189.4, CLtot 32.2 ml/min/kg), and high relative bioavailability (F = 59%). Kinetics are somewhat similar for 11-aza-artemisinin (t1/2 > 150 min, CLint = 576.9, CLtot = 75.0 ml/min/kg), although bioavailability is lower (F = 14%). In contrast, artemether is rapidly metabolized to dihydroartemisinin (DHA) (t1/2 = 17.4 min) and eliminated (CLint = 855.0, CLtot = 119.7 ml/min/kg) and has low oral bioavailability (F) of 2%. While artemisone displays low t1/2 of <10 min and high CLint of 302.1, it displays a low CLtot of 42.3 ml/min/kg and moderate bioavailability (F) of 32%. Its active metabolite M1 displays a much-improved t1/2 of >150 min and a reduced CLint of 37.4 ml/min/kg. Artemiside has t1/2 of 12.4 min, CLint of 673.9, and CLtot of 129.7 ml/kg/min, likely a reflection of its surprisingly rapid metabolism to artemisone, reported here for the first time. DHA is not formed from any amino-artemisinin. Overall, the efficacy and PK data strongly support the development of selected amino-artemisinins as components of new TACTs.

Wearable Technology May Assist in Retraining Foot Strike Patterns in Previously Injured Military Service Members: A Prospective Case Series

A rearfoot strike (RFS) pattern with increased average vertical loading rates (AVLR) while running has been associated with injury. This study evaluated the ability of an instrumented sock, which provides real-time foot strike and cadence audio biofeedback, to transition previously injured military service members from a RFS to a non-rearfoot strike (NRFS) running pattern. Nineteen RFS runners (10 males, 9 females) were instructed to wear the instrumented socks to facilitate a change in foot strike while completing an independent walk-to-run progression and lower extremity exercise program. Kinetic data were collected during treadmill running while foot strike was determined using video analysis at initial (T1), post-intervention (T2), and follow-up (T3) data collections. Nearly all runners (18/19) transitioned to a NRFS pattern following intervention (8 ± 2.4 weeks after the initial visit). Most participants (16/18) maintained the transition at follow-up (5 ± 0.8 weeks after the post-intervention visit). AVLR of the involved and uninvolved limb decreased 29% from initial [54.7 ± 13.2 bodyweights per sec (BW/s) and 55.1 ± 12.7 BW/s] to post-intervention (38.7 ± 10.1 BW/s and 38.9 ± 10.0 BW/s), respectively. This effect persisted 5-weeks later at follow-up, representing an overall 30% reduction on the involved limb and 24% reduction on the uninvolved limb. Cadence increased from the initial to the post-intervention time-point (p = 0.045); however, this effect did not persist at follow-up (p = 0.08). With technology provided feedback from instrumented socks, approximately 90% of participants transitioned to a NRFS pattern, decreased AVLR, reduced stance time and maintained these running adaptations 5-weeks later.

Comparison of chest X-ray interpretation by Emergency Department clinicians and radiologists in suspected COVID-19 infection: a retrospective cohort study

Objectives

We describe the inter-rater agreement between Emergency Department (ED) clinicians and reporting radiologists in the interpretation of chest X-rays (CXRs) in patients presenting to ED with suspected COVID-19.

Methods

We undertook a retrospective cohort study of patients with suspected COVID-19. We compared ED clinicians' and radiologists' interpretation of the CXRs according to British Society of Thoracic Imaging (BSTI) guidelines, using the area under the receiver operator curve (ROC area).

Results

CXRs of 152 cases with suspected COVID-19 infection were included. Sensitivity and specificity for 'classic' COVID-19 CXR findings reported by ED clinician was 84 and 83%, respectively, with a ROC area of 0.84 (95%CI 0.77 to 0.90). Accuracy improved with ED clinicians' experience, with ROC areas of 0.73 (95%CI 0.45 to 1.00), 0.81 (95%CI 0.73 to 0.89), 1.00 (95%CI 1.00 to 1.00) and 0.90 (95%CI 0.70 to 1.00) for foundation year doctors, senior house officers, higher speciality trainees and ED consultants, respectively (p < 0.001).

Conclusions

ED clinicians demonstrated moderate inter-rater agreement with reporting radiologists according to the BSTI COVID-19 classifications. The improvement in accuracy with ED clinician experience suggests training of junior ED clinicians in the interpretation of COVID-19 related CXRs might be beneficial. Large-scale survey studies might be useful in the further evaluation of this topic.

Advances in knowledge

This is the first study to examine inter-rater agreement between ED clinicians and radiologists in regards to COVID-19 CXR interpretation.Further service configurations such as 24-hr hot reporting of CXRs can be guided by these data, as well as an ongoing, nationwide follow-up study.

Repetitive Head Impacts in Football Do Not Impair Dynamic Postural Control

PURPOSE

The purpose of this study was to assess the effect of repetitive head impacts experienced by football players compared to noncontact athletes on dynamic postural control during both single-task (ST) and dual-task (DT) conditions.

METHODS

Thirty-four football players wearing accelerometer instrumented helmets and 13 cheerleaders performed a dynamic postural control battery, consisting of ST and DT gait initiation, gait, and gait termination, both prior to and following the football season. A 2 (group) × 2 (time) repeated measures ANOVA compared performance across 32 dynamic postural outcomes. A linear regression was performed on postural control change scores with common head impact kinematics serving as the independent variables.

RESULTS

The football players experienced a mean of 538.1 ± 409.1 head impacts in the season with a mean linear acceleration of 27.8g ± 3.2g. There were no significant interactions for any of the ST or DT dynamic postural control tasks. There was a significant relationship between head impact kinematics and the lateral center of pressure displacement during the anticipatory postural adjustment phase (r = 0.26, P = 0.010) and transitional phase (r = 0.511, P = 0.042) during ST gait initiation. For both measures, the number of impacts exceeding 98g was the only significant predictor of decreased center of pressure displacement.

CONCLUSIONS

A single competitive football season did not adversely affect dynamic postural control when comparing football players to cheerleaders who do not experience repetitive head impacts. Furthermore, there were limited relationships with head impact kinematics suggesting that a single season of football does not adversely affect most outcome measures of instrumented dynamic postural control. These findings are consistent with most studies which fail to identify clinical differences related to repetitive head impacts.

Association of Optic Nerve Head Drusen with Best Vitelliform Macular Dystrophy: A Case Series

Purpose

To report the association of optic nerve head (ONH) drusen with Best vitelliform macular dystrophy (BVMD).

Methods

Chart review.

Patients

Five patients from 3 families.

Results

Multimodal imaging and ophthalmic examination demonstrated findings consistent with ONH drusen, in association with BVMD, in 5 patients.

Conclusion

We report the association of BVMD with ONH drusen in 5 patients. This combination has previously been reported only once. We recommend that patients with a diagnosis of BVMD undergo autofluorescence and ultrasound imaging of the optic nerve to help facilitate this diagnosis, as some ONH drusen can be buried.

Integrated geometric and mechanical analysis of an image-based lymphatic valve

Lymphatic valves facilitate the lymphatic system's role in maintaining fluid homeostasis. Malformed valves are found in several forms of primary lymphœdema, resulting in incurable swelling of the tissues and immune dysfunction. Their experimental study is complicated by their small size and operation in low pressure and low Reynolds number environments. Mathematical models of these structures can give insight and complement experimentation. In this work, we present the first valve geometry reconstructed from confocal imagery and used in the construction of a subject-specific model in a closing mode. A framework is proposed whereby an image is converted into a valve model. An FEA study was performed to identify the significance of the shear modulus, the consequences of smoothing the leaflet surface and the effect of wall motion on valve behaviour. Smoothing is inherent to any analysis from imagery. The nature of the image, segmentation and meshing all cause attenuation of high-frequency features. Smoothing not only causes loss of surface area but also the loss of high-frequency geometric features which may reduce stiffness. This work aimed to consider these effects and inform studies by taking a manual reconstruction and through manifold harmonic analysis, attenuating higher frequency features to replicate lower resolution images or lower degree-of-freedom reconstructions. In conclusion, two metrics were considered: trans-valvular pressure required to close the valve, ΔP_c, and the retrograde volume displacement after closure. The higher ΔP_c, the greater the volume of lymph that will pass through the valve during closure. Retrograde volume displacement after closure gives a metric of compliance of the valve and for the quality of the valve seal. In the case of the image-specific reconstructed valve, removing features with a wavelength longer than four μm caused changes in ΔP_c. Varying the shear modulus from 10 kPa to 60 kPa caused a 3.85-fold increase in the retrograde volume displaced. The inclusion of a non-rigid wall caused ΔP_c to increase from 1.56 to 2.52 cmH₂O.

The effect of minimalist footwear and instruction on running: an observational study

Background

It is not known whether the effects on altered running style which are attributed to minimalist footwear can be achieved by verbal instructions in standard running shoes (SRS).

Aim

To explore the effect of Vibram FiveFingers (VFF) versus SRS plus running instruction on lower extremity spatiotemporal parameters and lower limb joint kinematics.

Methods

35 healthy subjects (mean=30 years, 18 females) were assessed on two occasions with 3D motion analysis. At each session subjects ran on a treadmill (3.58 m/s) for 2 min in either VFF or SRS (randomised order); with and without running instruction. Differences between spatiotemporal parameters and lower limb joint kinematics between conditions were assessed using a 2x2 repeated-measures ANOVA.

Results

Wearing VFF significantly increased cadence (p<0.001) and reduced stride length (p<0.01). Prior to initial contact, both instruction and VFF significantly increased foot (p<0.001 and p=0.02, respectively) and ankle (p<0.001 and p=0.02, respectively) plantarflexion, while wearing VFF significantly increased knee extension (p=0.04). At initial contact, instruction significantly increased knee flexion (p=0.04), and foot (p=0.001) and ankle (p=0.03) plantarflexion. At mid-stance and toe-off, instruction significantly increased knee flexion (p=0.048 and p<0.001, respectively) and foot plantarflexion (p<0.001 and p=0.01, respectively). Instruction had a greater effect on increasing knee flexion (p=0.007) and plantarflexion angle (p<0.001) when subjects wore SRS and VFF, respectively.

Conclusion

Alterations in spatiotemporal parameters observed when running in VFF are likely to be attributable to the minimalist footwear. However, the kinematic adaptations observed following instruction suggests that changes in joint angles previously attributed to minimalist footwear alone may be similarly achieved with instruction.

The association of flushing bother, impact, treatment satisfaction and discontinuation of niacin therapy

BACKGROUND

Niacin has lipid-modifying efficacy and cardiovascular benefit, but is underutilised because of niacin-induced flushing (NIF). This real-world, prospective, observational study characterised the severity and impact of NIF symptoms among participants who were newly prescribed extended-release (ER) niacin.

METHODS

Participants were surveyed daily during week 1 of therapy, at weeks 5, 9, 13, and at months 7, 10 and 13. Surveys included the Flushing Symptom Questionnaire (FSQ), which includes the Global Flushing Severity Score (GFSS) question, the Flushing Impact Questionnaire (FIQ) and the Treatment Satisfaction Questionnaire for Medication (TSQM).

RESULTS

Overall, 306 participants were enrolled. During week 1, 30.0% of participants reported a maximum GFSS ≥ 4 (moderate or greater). Mean FIQ domain scores increased with increasing flushing severity, primarily driven by the Irritation/Frustration domain. By week 13, only 2.5% of participants had attained a 2 g ER niacin dose. By month 13, 43.5% (n = 133) had discontinued ER niacin. At discontinuation, only 3.1% of participants had attained the 2 g dose. Over half of the participants who discontinued experienced flushing symptoms: 82% reported moderate to extreme flushing (GFSS ≥ 4), and 68% reported severe to extreme flushing (GFSS ≥ 7). Participants who discontinued and had flushing side effects reported high degrees of impact in the FIQ Irritation/Frustration domain, and high dissatisfaction as a result of side effects, as measured by the TSQM.

CONCLUSION

In a real-world setting, NIF side effects were bothersome and had an impact on the continuation of therapy.

A discrete-choice experiment of United Kingdom patients' willingness to risk adverse events for improved function and pain control in osteoarthritis

OBJECTIVE

To assess patient preferences for treatment-related benefits and risks associated with the use of nonsteroidal anti-inflammatory drugs (NSAIDs) in the management of osteoarthritis (OA).

DESIGN

Using a chronic-illness panel in the United Kingdom, patients 45 years or older with a self-reported diagnosis of OA were eligible to participate in the study. Patient preferences were assessed using a discrete-choice experiment that compared hypothetical treatment profiles of benefits and risks consistent with NSAID use. Benefit outcomes (ambulatory pain, resting pain, stiffness, and difficulty doing daily activities) were presented on a 0-to-100 mm scale. Risk outcomes (bleeding ulcer, stroke, and myocardial infarction [MI]) were expressed as probabilities over a fixed time period. Each patient answered 10 choice tasks comparing different treatment profiles. Preference weights were estimated using a random-parameters logit model.

RESULTS

Final sample included 294 patients. Patients ranked reductions in ambulatory pain and difficulty doing daily activities (both: 6.32; 95% confidence interval [CI]: 5.0-7.6) as the most important benefit outcomes, followed by reductions in resting pain (2.80; 95% CI: 1.8-3.8) and stiffness (2.65; 95% CI: 0.9-4.4). Incremental changes (3%) in the risk of MI or stroke were assessed as the most important risk outcomes (10.00; 95% CI: 8.2-11.8; and 8.90; 95% CI: 7.3-10.5, respectively).

CONCLUSION

Patients ranked ambulatory pain as a more important benefit than resting pain; likely due to its impact on ability to do daily activities. For a 25-mm reduction, patients were willing to accept four times the risk of MI in ambulatory pain vs resting pain.

Titration of synaptotagmin I expression differentially regulates release of norepinephrine and neuropeptide Y

Synaptotagmin (syt) I is a Ca(2+) sensor that has been thought to trigger all vesicle secretion with similar mechanisms. However, given the calcium and stimulation requirements of small clear, and large dense core vesicles, we hypothesized that syt I expression differentially regulates vesicle release. Therefore, in this study, we generated multiple stable cell lines of PC12 cells that each had a different and stable level of syt I expression. We determined the functional effects of titrated syt I expression on transmitter release from the two vesicle types, and showed that the transmitters, norepinephrine (NE) and neuropeptide Y (NPY), each have a threshold level of syt I expression required for their release that is different for the two transmitter types. We used carbon fiber amperometry to measure release of NE from single vesicles, and found that release ranged from 50% to 100% in the syt I-targeted cells compared to release from control cells. We used an immunoassay to measure NPY release and found that NPY release was abolished in cells that had abolished syt I expression, but cell lines that expressed 50-60% of control levels of syt I exhibited NPY release levels comparable to release of NPY from control cells. Furthermore, the vesicle fusion pore exhibited a reduced open duration when syt I was abolished, but a longer open duration time for 50% syt I expression than control cells. Therefore, vesicles have a threshold for syt I that is required to control opening of the fusion pore, expansion, and full fusion to release large dense core proteins, but not for full fusion of the small molecules like NE.

Measuring flushing symptoms with extended-release niacin using the flushing symptom questionnaire: results from a randomised placebo-controlled clinical trial

INTRODUCTION

Niacin is underutilised because of flushing. Lack of a quantitative tool to assess niacin-induced flushing has precluded the objective evaluation of flushing associated with extended-release (ER) niacin formulations. We developed the Flushing Symptom Questionnaire((c)) (FSQ), a quantitative tool to assess patient-reported flushing, and assessed its ability to characterise ER niacin-induced flushing.

METHODS

This study focused on the responses to one question in the FSQ, the Global Flushing Severity Score (GFSS), reported on a 0-10 scale (none = 0, mild = 1-3, moderate = 4-6, severe = 7-9 and extreme = 10) to assess flushing during ER niacin initiation (week 1) and maintenance (weeks 2-8).

RESULTS

Flushing severity with ER niacin was greatest during week 1 and remained greater than placebo for the study duration. During weeks 2-8, 40% of patients on ER niacin vs. 8% of those on placebo had > 1 day/week with 'moderate or greater' GFSS.

CONCLUSIONS

In conclusion, the GFSS component of the FSQ was a sensitive and responsive quantitative measure of ER niacin-induced flushing that will aid in the objective comparison of novel strategies intended to improve tolerability and adherence to niacin, an agent proven to reduce cardiovascular risk.

Neurotrophin-mediated neuroprotection of hippocampal neurons following traumatic brain injury is not associated with acute recovery of hippocampal function

Traumatic brain injury (TBI) causes selective hippocampal cell death which is believed to be associated with the cognitive impairment observed in both clinical and experimental settings. The endogenous neurotrophin-4/5 (NT-4/5), a TrkB ligand, has been shown to be neuroprotective for vulnerable CA3 pyramidal neurons after experimental brain injury. In this study, infusion of recombinant NT-4/5 increased survival of CA2/3 pyramidal neurons to 71% after lateral fluid percussion brain injury in rats, compared with 55% in vehicle-treated controls. The functional outcome of this NT-4/5-mediated neuroprotection was examined using three hippocampal-dependent behavioral tests. Injury-induced impairment was evident in all three tests, but interestingly, there was no treatment-related improvement in any of these measures. Similarly, injury-induced decreased excitability in the Schaffer collaterals was not affected by NT-4/5 treatment. We propose that a deeper understanding of the factors that link neuronal survival to recovery of function will be important for future studies of potentially therapeutic agents.

In vivo and ex vivo MRI detection of localized and disseminated neural stem cell grafts in the mouse brain

The application of stem cells as delivery vehicles opens up the opportunity for targeting therapeutic proteins to the damaged or degenerating central nervous system. Neural stem cell (NSC) lines have been shown to engraft, differentiate and correct certain central nervous system diseases. The present study was performed to test the ability of magnetic resonance imaging (MRI) in detecting transplanted NSCs under conditions of limited migration in the normal adult mouse brain versus widespread migration when the cells are transplanted neonatally. The C17.2 NSC line was labeled in vitro with superparamagnetic iron oxide (SPIO) particles and the labeled cells were implanted intracranially. Serial in vivo gradient echo MR imaging was performed using a 4.7 T horizontal bore magnet. High resolution ex vivo images of the isolated brains were performed at 9.4 T, and the presence of iron was correlated with Prussian blue staining in histological sections. Adult animals injected with SPIO-labeled stem cells exhibited hypointense regions near the injection site that were observed up to 32 days after injection. In neonatally transplanted animals, MR signal intensity from transplanted NSCs was not apparent in in vivo imaging but ex vivo MR images revealed small hypointense regions throughout the brain including the olfactory bulbs, cortex and the cerebellum, reflecting the wide distribution of the engrafted cells. These regions were correlated with Prussian blue staining, which confirmed the presence of SPIO particles inside the engrafted cells. We have shown that MRI is capable of differentiating localized and widespread engraftment of C17.2 stem cells in the central nervous system.

Use of gastroprotective agents and discontinuations due to dyspepsia with the selective cyclooxygenase-2 inhibitor etoricoxib compared with non-selective NSAIDs

BACKGROUND

Most nonsteroidal anti-inflammatory drugs (NSAIDs) are non-selective cyclooxygenase-1 (COX-1) and COX-2 inhibitors and are associated with upper gastrointestinal (GI) dyspeptic symptoms often resulting in GI co-medication usage or treatment discontinuation.

OBJECTIVE

To compare the rates of new use of gastroprotective agents and discontinuations due to dyspepsia with the COX-2 selective inhibitor etoricoxib compared with non-selective NSAIDs.

RESEARCH DESIGN AND METHODS

This pre-specified combined analysis used data from nine randomized, double-blind, controlled, clinical trials with etoricoxib in patients with osteoarthritis, rheumatoid arthritis, chronic low back pain, or ankylosing spondylitis. The cumulative incidences of (1) new use (new prescription or increased dose) of gastroprotective agents (GPA) and (2) discontinuation due to dyspeptic symptoms were compared among patients treated with etoricoxib (60 mg, 90 mg, or 120 mg daily) vs. non-selective NSAIDs (diclofenac 50 mg. t.i.d. or naproxen 500 mg. b.i.d.).

RESULTS

The overall rates/100 patient-years for new use of GPAs were 9.1 and 13.0 for etoricoxib and NSAIDs, respectively (RR = 0.75; 95% confidence interval [CI] 0.64, 0.89; p < 0.001). A benefit with etoricoxib was seen in the first 6 months when most new GPA usage occurred; after 6 months new use of GPAs was similar between etoricoxib and NSAIDs. The rates/100 patient-years of treatment discontinuation due to dyspeptic symptoms with etoricoxib and NSAIDs were 1.5 and 2.7, respectively (RR = 0.60; 95% CI 0.41, 0.87; p = 0.007). Analyses of placebo-controlled treatment periods showed significantly more new GPA use and more discontinuations due to dyspeptic symptoms with NSAIDs vs. placebo, but not with etoricoxib vs. placebo.

CONCLUSION

In this combined analysis of clinical trials of patients with OA, RA, chronic low back pain, or AS, new use of gastroprotective agents was significantly lower with etoricoxib than with the comparator non-selective NSAIDs during the initial 6 months of treatment and similar thereafter. There were significantly fewer discontinuations for dyspeptic symptoms with etoricoxib than with NSAIDs over the entire follow-up period.

Initiation of antihypertensive therapy among new users of cyclooxygenase-2-selective and nonselective NSAIDs

BACKGROUND

The comparative effects of cyclooxygenase-2- (COX-2) selective inhibitors and nonselective, nonsteroidal anti-inflammatory drugs (NSAIDs) on blood pressure are debated. Clinicians have been concerned about the need for antihypertensive treatment following therapy with these agents.

OBJECTIVE

To compare initiation of antihypertensive treatment among new users of the COX-2-selective inhibitor rofecoxib and of nonselective NSAIDs in clinical practice.

METHODS

Retrospective cohort study using the MediPlus (UK) database that covers 1.8 million patients throughout the UK. Patients included were at least 50 years of age, had at least 1 prescription for either diclofenac, ibuprofen, naproxen or rofecoxib (drugs of interest, DOIs), and had no prescription for any NSAID, COX-2 inhibitor, or antihypertensive treatment during the 6 months prior to their first/index prescription date. A subset of patients, classified as chronic and persistent new users, had at least 3 prescriptions of the index prescription DOI and did not switch to another DOI during the 6-month follow-up period. Logistic regression analysis, adjusted for potential predictors, was used to assess initiation of new antihypertensive treatment.

RESULTS

18,737 suitable patients were identified (diclofenac 7,861, ibuprofen 8,423, naproxen 1,556 and rofecoxib 897). Those using rofecoxib were older and more likely to be female than those using NSAIDs. During the 6 months following the index prescription, 7.0% of all new users and 11.5% of chronic and persistent new users initiated antihypertensive treatment. After adjusting for potential predictors there were no statistically significant differences in the risk of initiating antihypertensive treatment between new or chronic and persistent new users of rofecoxib, diclofenac, ibuprofen and naproxen (p > 0.05).

CONCLUSION

The results of this study did not indicate any significant differences in the initiation of antihypertensive therapy among patients who were prescribed rofecoxib and NSAIDs, even after multiple prescriptions.

Materials for restoration of primary teeth: 2. Glass ionomer derivatives and compomers

A wide variety of materials have been used for the restoration of primary teeth. Resin-modified glass ionomers and the more recently introduced viscous glass ionomers have been developed from conventional glass ionomer materials in an attempt to overcome the suboptimal properties of conventional glass ionomers. These materials would appear to have the necessary physical characteristics for restorations in load-bearing situations in primary teeth, as have the resin-based compomer materials, which now have well documented success rates in a number of studies. The first of these two articles described 'traditional' restorative materials, including amalgam and conventional glass ionomer, for the restoration of primary teeth. This paper describes materials derived from traditional glass ionomers in an attempt to overcome the suboptimal properties of conventional glass ionomers and resin-based materials such as compomer.

Use of nonsteroidal anti-inflammatory drugs and gastroprotective agents before the advent of cyclooxygenase-2-selective inhibitors: analysis of a large United States claims database

BACKGROUND

Previous studies have shown that 20% to 40% of patients requiring nonsteroidal anti-inflammatory drugs (NSAIDs) are concomitantly prescribed gastroprotective agents (GPAs) such as proton pump inhibitors (PPIs) and H2-receptor antagonists.

OBJECTIVE

The purpose of this study was to examine NSAID prescription patterns and the concurrent use of GPAs in a large national sample of patients who were prescribed NSAIDs for the first time.

METHODS

Patterns of NSAID use, particularly chronic NSAID use, and of concomitant use of GPAs were examined using a large US-based prescription database. Patients with at least 1 NSAID prescription dispensed between May 1 and August 31, 1998, were identified. Persons with any NSAID prescription within 4 months prior to the first (index) prescription were excluded. The remaining patients were defined as new NSAID users and then classified as chronic users (> or = 30 days of supply of NSAIDs during the 120 days of follow-up after the first NSAID prescription) or acute users (<30 days of NSAID supply during the 120 days of follow-up). Concomitant GPA use was defined as receipt of any GPA prescription between the fill date of NSAID prescription and 125% of days of supply. NSAIDs included diclofenac/misoprostol (in a fixed combination), diclofenac, naproxen, nabumetone, ibuprofen, and "other" (comprising several less frequently prescribed agents). Patients were classified as users of a particular NSAID based on the first NSAID prescription they received. GPAs included PPIs, H2-receptor antagonists, and misoprostol.

RESULTS

A total of 3,028,808 new NSAID users were identified. Chronic NSAID users (47.8% of the sample) were older than acute users. The percentage of new chronic users aged > or = 65 years for each of the NSAIDs was 41.2% for diclofenac/ misoprostol, 33.0% for nabumetone, 30.8% for diclofenac, 20.4% for naproxen, and 20.3% for ibuprofen. The percentage of women was higher among patients treated with diclofenac/misoprostol than among patients treated with all other NSAIDs (P < 0.001). During the 120 days of follow-up, the percentages of NSAID users with concomitant GPA use were 22.7% for diclofenac/misoprostol, 16.3% for diclofenac, 11.5% for naproxen, 18.0% for nabumetone, 12.3% for ibuprofen, and 14.8% for other NSAIDs. Based on days of supply, the rates of concomitant GPA use were 31.1%, 23.6%, 17.6%, 27.3%, 18.8%, and 22.5% for diclofenac/misoprostol, diclofenac, naproxen, nabumetone, ibuprofen, and other NSAID users, respectively. Among those who were taking GPAs before the NSAID index prescription date, -89% continued GPA therapy.

CONCLUSIONS

Approximately 22% of the days of NSAID supply were covered by GPAs. Prior GPA use was the strongest predictor of subsequent concomitant GPA/ NSAID use. Differences in GPA use were observed among patients using different NSAIDs.

Materials for restoration of primary teeth: I. Conventional materials and early glass ionomers

This paper demonstrates how the treatment of primary dentition may present the clinician with increased difficulties compared with the preparation and placement of restorations in adult dentition. Established dental materials (dental amalgam and conventional glass ionomer cements) and less well established alternative materials (copper cements) are reviewed. The use of amalgam to restore primary dentition is the subject of concern amongst the dental profession in terms of lack of adhesion and potential toxicity concerns, while the low tensile strength of traditional glass ionomer cements make them less suitable for the restoration of primary dentition.

Gastrointestinal medications and procedures in osteoarthritis patients treated with rofecoxib compared with nonselective NSAIDs

CONTEXT

Patients treated with nonselective cyclooxygenase inhibitors (nonsteroidal anti-inflammatory drugs [NSAIDs]) often experience dyspepsia and upper gastrointestinal (GI) adverse effects, and frequently require GI comedications and diagnostic procedures.

OBJECTIVE

This study combined existing data to test the hypothesis that GI comedications and GI diagnostic procedures occur less frequently in osteoarthritis (OA) patients treated with rofecoxib compared with nonselective NSAIDs.

DESIGN

Combined analysis of 8 randomized controlled clinical trials.

SETTING

Rheumatology and general practice clinics.

PATIENTS

Men and women aged 40 years and older with OA.

INTERVENTIONS

Random assignment to placebo (n = 514), rofecoxib (n = 3357; 12.5, 25, or 50 mg daily combined; average 24.7 mg), or NSAIDs (n = 1564; ibuprofen 800 mg thrice daily, diclofenac 50 mg thrice daily, or nabumetone 1500 mg daily, combined).

MAIN OUTCOME MEASURES

The cumulative incidence of patients using GI comedications (antacids, antispasmodics, antiflatulents, antiregurgitants, H2 antagonists, proton pump inhibitors, sucralfate, prostaglandins, other antiulcer therapy) and needing GI procedures (upper GI barium studies, upper or lower GI endoscopies) over 12 months.

RESULTS

Compared with those treated with NSAIDs, patients treated with rofecoxib had a significantly lower incidence of GI comedication use (17.5% vs 27.0%, P <.001) and GI procedures (3.3% vs 5.3%, P =.02) over 12 months. Similar results were seen in analyses of protocols with placebo; in these studies, rates of GI comedications and procedures were highest with NSAIDs, while those with rofecoxib and placebo were similar to each other.

CONCLUSIONS

OA patients treated with rofecoxib for up to 12 months required significantly less GI comedication and significantly fewer GI procedures than those treated with NSAIDs.

Economic evaluation of rofecoxib versus nonselective nonsteroidal anti-inflammatory drugs for the treatment of osteoarthritis

BACKGROUND

Results of phase III clinical trials of rofecoxib, a selective inhibitor of cyclooxygenase 2, have shown that osteoarthritis patients treated with rofecoxib had significantly fewer clinically significant gastrointestinal (GI) adverse events than those who received nonselective nonsteroidal anti-inflammatory drugs (NSAIDs).

OBJECTIVE

This paper explores the potential economic implications of the use of rofecoxib versus nonselective NSAIDs for the treatment of osteoarthritis via a decision analytic model based on rofecoxib clinical data and the published literature.

METHODS

Base-case 1-year analyses were done with data on GI adverse events, specifically perforations, ulcers, and bleeds (PUBs), obtained from a prespecified pooled analysis of the rofecoxib clinical trials. Analyses were also performed using pooled results of two 12-week endoscopic surveillance trials, with adjustments for silent ulcers of 40% and 85%.

RESULTS

Under base-case conditions, the expected cost savings in GI problems and comedications averted with rofecoxib versus NSAIDs was 0.81 dollars per day, representing an 85% offset of the difference in drug price. For rofecoxib versus NSAIDs, the expected cost per PUB avoided with rofecoxib was 4738 dollars, and expected cost per year of life saved was 18,614 dollars. In analyses based on endoscopic data, therapy with rofecoxib was less expensive than therapy with NSAIDs, regardless of silent ulcer adjustment. Results were most sensitive to prophylactic GI comedication rates, and were robust over a range of model assumptions and costs.

CONCLUSIONS

In this analysis based on differences in clinically significant GI events for osteoarthritis patients, cost differences between rofecoxib and NSAIDs were markedly offset by expected cost savings in GI problems and comedications averted with rofecoxib. Costs per year of life saved with rofecoxib versus NSAIDs were well within accepted benchmarks for cost-effectiveness. When endoscopic data alone were considered, rofecoxib was cost saving across all assumptions about silent ulcer rates.

Effect of rofecoxib therapy on measures of health-related quality of life in patients with osteoarthritis

BACKGROUND

Bodily pain and physical disability can negatively impact health-related quality of life (HRQL) in patients with osteoarthritis (OA).

OBJECTIVE

To assess the effects of treatment with a new agent, rofecoxib, on HRQL in patients with OA.

STUDY DESIGN

Randomized, double-blind, 6-week clinical trial comparing treatment with rofecoxib, 5 to 50 mg, with placebo in 672 patients with OA of the hip or knee.

MAIN OUTCOME MEASURE

Patient HRQL was assessed at baseline and at the end of treatment using the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36).

RESULTS

At 6 weeks, mean change from baseline in all SF-36 mental and physical health domain scores demonstrated significant improvement with rofecoxib use (P < .05 for all doses for all SF-36 domains), with evidence of a dose-response relation. Improvements in mental and physical HRQL domains with rofecoxib treatment were significantly greater than those with placebo treatment (P < .05 for each dose of rofecoxib vs placebo for all domains except general health) and highly correlated with improvements observed using disease-specific OA outcome measures such as the Western Ontario and McMaster Universities Osteoarthritis Index-visual Analog 3.0 OA index pain and physical function subscales. The effect of rofecoxib vs placebo treatment on mental health largely disappeared after adjustment for improvement in OA disease-specific measures.

CONCLUSIONS

Rofecoxib treatment increased physical and mental HRQL domain scores on the SF-36. Improvements in mental health with rofecoxib use primarily resulted from effective treatment of OA (i.e., reduction in pain and improvement in physical function).

Gastrointestinal-related healthcare resource usage associated with a fixed combination of diclofenac and misoprostol versus other NSAIDs

OBJECTIVE

To compare gastrointestinal (GI) healthcare resource use (HCRU) and associated costs in patients taking a fixed combination of diclofenac and misoprostol versus other nonsteroidal anti-inflammatory drugs (NSAIDs).

METHODS

We analysed a sample (49,033 patients) of the Government of Quebec Health Insurance Agency database. Patients were included in the study if they did not have GI events during the year preceding the date of their first NSAID prescription dispensing (the index date). Patients were followed up for 2 years. A 3-stage model was used to determine the factors that influenced the direct medical costs of GI HCRU: (i) a logistic regression model (model 1) to estimate the risk of GI HCRU; (ii) a linear regression model (model 2) to estimate the direct costs of GI HCRU for those who had such events; (iii) multiplying the estimated risks from model 1 by the estimated costs from model 2 gave the estimated direct costs of GI HCRU for all patients.

STUDY PERSPECTIVE

Provincial government of Quebec, Canada.

RESULTS

1,533 patients were prescribed diclofenac/misoprostol at the index date and 10,540 another NSAID. Comorbidity markers were not significantly different between the 2 groups. Of the diclofenac/misoprostol patients, 23 (1.5%) were hospitalised for GI problems compared with 194 (1.8%) of the NSAID group; 403 (26.3%) of diclofenac/misoprostol patients used gastroprotective agents compared with 2,849 (27.0%) of the NSAID patients; 118 (7.7%) of diclofenac/misoprostol patients had GI diagnostic tests compared with 682 (6.5%) of the NSAID patients. The average direct medical cost of GI HCRU was 310.52 Canadian dollars ($Can)/patient (1997 values) in the diclofenac/misoprostol group compared with $Can231.19/patient (1997 values) in the NSAID group. When adjusted for baseline factors, the ratio of the total direct medical cost of GI HCRU in the diclofenac/misoprostol group to that of the NSAID group was 1.15 (95% confidence interval: 0.89, 1.48).

CONCLUSIONS

Our data showed no significant differences in GI HCRU among patients taking diclofenac/misoprostol compared with those taking NSAIDs.

Minimal perceptible clinical improvement with the Western Ontario and McMaster Universities osteoarthritis index questionnaire and global assessments in patients with osteoarthritis

OBJECTIVE

To determine the minimal perceptible clinical improvement (MPCI) in patients with osteoarthritis (OA) with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire, and patient and investigator global assessment of disease status in randomized clinical trials for treatment of OA.

METHODS

Subjects with OA of the knee or hip were randomized to receive either rofecoxib 12.5 or 25 mg once daily, ibuprofen 800 mg 3 times daily, or placebo for 6 weeks. The WOMAC and global assessments were completed at baseline and Weeks 2, 4, and 6. A patient global assessment of response to therapy (0 to 4 scale) was used to "anchor" the WOMAC scores. MPCI was defined as the difference in mean change from baseline in WOMAC (100 mm normalized visual analog scale, VAS) between patients with 0 = "None" global response to therapy and patients with 1 = "Poor" global response to therapy.

RESULTS

MPCI was determined to be 9.7, 9.3, and 10.0 mm for the WOMAC pain, physical function and stiffness subscales, respectively, and 11.1 mm for WOMAC question 1: Pain walking on a flat surface. The MPCI for the investigator was 0.4 with investigator assessment of disease status reported on a 0 to 4 Likert scale. Of note, the estimated MPCI for the WOMAC and investigator globals were similar irrespective of treatment, sex, age, or geographic region.

CONCLUSION

In this analysis, mean changes of roughly 9 to 12 mm (100 mm normalized VAS) on WOMAC scales were perceptible changes to patients with hip and knee OA. A mean decrease of 0.4 in global disease status (0 to 4 Likert scale) as assessed by the investigator corresponded to the patients' MPCI. Understanding the minimal perceptible differences may permit a better assessment of the clinical relevance of therapeutic interventions in OA.

Gastrointestinal tolerability of the selective cyclooxygenase-2 (COX-2) inhibitor rofecoxib compared with nonselective COX-1 and COX-2 inhibitors in osteoarthritis

BACKGROUND

Most nonsteroidal anti-inflammatory drugs (NSAIDs) are nonselective cyclooxygenase (COX-1 and COX-2) inhibitors and are associated with a variety of upper gastrointestinal (GI) tract symptoms. The roles of COX-1 and COX-2 in the pathogenesis of these symptoms are unclear. To test whether COX-2 inhibition with rofecoxib would have greater GI tolerability than nonselective COX-1 and COX-2 inhibition, we compared the incidences of (1) treatment discontinuations for GI adverse events (AEs) and (2) prespecified dyspeptic-type GI AEs among patients with osteoarthritis treated with rofecoxib vs NSAIDs.

METHODS

A prespecified, combined analysis of investigator-reported GI AEs in all 8 double-blind, randomized, phase 2b/3 osteoarthritis trials of rofecoxib was conducted. Patients included men and women with osteoarthritis (N = 5435); there was no upper age limit for entry. Treatments tested included rofecoxib, 12.5, 25, or 50 mg (combined), vs ibuprofen, diclofenac, or nabumetone (combined). Primary outcomes were the time (by survival analysis) to (1) treatment discontinuation due to GI AEs and (2) first reported dyspeptic-type GI AE. Between-treatment comparisons were made by log-rank test.

RESULTS

The number of treatment discontinuations caused by GI AEs during 12 months was significantly lower (P=.02) with rofecoxib vs NSAIDs (8.2 vs 12.0 per 100 patient-years; relative risk, 0.70; 95% confidence interval, 0.52-0.94). The incidence of prespecified dyspeptic-type GI AEs during the first 6 months was significantly lower (P=.02) with rofecoxib vs NSAIDs (69.3 vs 85.2 per 100 patient-years; relative risk, 0.85; 95% confidence interval, 0.74-0.97). However, the difference between treatments in dyspeptic-type GI AEs was attenuated after 6 months.

CONCLUSION

Rofecoxib was associated with a lower incidence of treatment discontinuations due to GI AEs over 12 months and a lower incidence of dyspeptic-type GI AEs over 6 months than treatment with nonselective COX inhibitors, or NSAIDs. Arch Intern Med. 2000;160:2998-3003

Application of the National Cholesterol Education Program and joint European treatment criteria and clinical benefit in the Air Force/Texas Coronary Atherosclerosis Prevention Study (AFCAPS/TexCAPS)

AIMS

The Air Force/Texas Coronary Atherosclerosis Prevention Study reported that diet with lovastatin, 20-40 mg daily, reduced the risk for a first coronary event by 37%. Because only 17% of this cohort would have qualified for drug therapy according to current U.S. guidelines, we assessed clinical benefit by risk categories.

METHODS AND RESULTS

The main outcome measures were event rates of first acute major coronary events stratified by National Cholesterol Education Program and European criteria and target goal. Both those who would and would not be eligible for drug therapy, according to National Cholesterol Education Program guidelines, benefited from intervention. As expected, drug-eligible participants (event rate: lovastatin 1%/year, placebo 1.87%/year [relative risk 0.53, 95% confidence interval: 0.33, 0.84]) were at greater absolute risk for acute major coronary events than non-eligible participants (lovastatin 0.62%/year, placebo 0.93%/year [relative risk 0.67, 95% confidence interval: 0.51, 0.88]). Similar results were found using European guidelines for coronary risk management. Treatment to a target goal suggested a non-significant trend to greater benefit.

CONCLUSIONS

The consistent relative benefit across risk categories suggests that it may be possible to improve identification of at-risk persons who would benefit from primary prevention, and to recommend appropriate goals of such treatment.

Gastrointestinal symptoms and health related quality of life in patients with arthritis

OBJECTIVE

To evaluate the relationship between gastrointestinal (GI) symptoms and health related quality of life (QOL) in patients with osteoarthritis (OA) and rheumatoid arthritis (RA).

METHODS

A total of 1773 patients with arthritis participating in a longterm outcome study (OA of the hip or knee = 648, RA = 1125) completed mailed surveys that included assessments of GI symptoms and overall GI symptom severity, Short Form-36, the visual analog scale (VAS) for the EuroQol (Health QOL), a VAS global disease severity scale, and measures of disease and psychological status. The overall response rate exceeded 85%.

RESULTS

Dyspepsia (heartburn, bloating, or belching) and upper abdominal/epigastric pain were identified as the most important GI contributors to reduction in QOL, and the simultaneous presence of both these symptoms was associated with lower QOL (54.5) compared to those without symptoms (70.9) on the 0-100 Health QOL scale. Similarly, those in the upper tertile of the global GI severity scale had Health QOL scores of 55.7 compared to 76.4 for those in the lower tertile. These differences in GI symptoms and GI severity, however, were reduced substantially when the effects of functional disability, pain, and depression were adjusted for: 62.3 to 68.6 (p = 0.003) and 63.7 to 70.3 (p<0.001) for the GI symptoms and GI severity scales, respectively.

CONCLUSION

QOL is significantly impaired among unselected arthritis patients with GI symptoms compared to those without these symptoms. Dyspepsia and upper abdominal/epigastric pain are more strongly related to QOL measures than other GI symptoms, and are common among arthritis patients. It is possible to construct a simple scale of these 2 symptoms or to use the VAS GI severity scale and get a clinically useful idea of the current level of GI distress and alteration of QOL by GI problems. Two components of impairment can be identified, one that is smaller and unrelated to disease or psychological factors, and a second that is larger and includes these factors. Because GI symptoms can alter function, pain, and psychological status, it is likely that the true effect of GI symptoms on QOL is somewhere between the unadjusted and adjusted values cited above.

Air Force/Texas Coronary Atherosclerosis Prevention Study (AFCAPS/TexCAPS): baseline characteristics and comparison with USA population

BACKGROUND

Results of the Air Force/Texas Coronary Atherosclerosis Prevention Study (AFCAPS/TexCAPS) demonstrated that treatment with lovastatin, in addition to modifications of diet and lifestyle, reduced the rate of first acute major coronary events compared with placebo in a cohort that included participants with average to mildly elevated total levels of cholesterol, and below average levels of high-density lipoprotein cholesterol, women, and elderly subjects.

OBJECTIVE

To describe the baseline characteristics of the study's cohort.

DESIGN

This was a double-blind, placebo-controlled, primary-prevention trial in which Americans with average to mildly elevated total levels of cholesterol [4.65-6.83 mmol/l (180-264 mg/dl)] and no clinical evidence of atherosclerotic cardiovascular disease were randomly allocated either 20-40 mg/day lovastatin or placebo in addition to a low-saturated fat, low-cholesterol diet. Baseline characteristics of the study cohort are described, and the characteristics of a USA reference population based upon NHANES III data are provided for comparison.

RESULTS

The study includes 5608 men (85%) and 997 women (15%) with mean total cholesterol level 5.71 +/- 0.54 mmol/l (221 +/- 21 mg/dl), low-density lipoprotein cholesterol level 3.88 +/- 0.44 mmol/l (150 +/- 17 mg/dl), high-density lipoprotein cholesterol 0.96 +/- 0.15 mmol/l (37 +/- 6 mg/dl), and median triglyceride level 1.78 +/- 0.86 mmol/l (158 +/- 76 mg/dl). The mean age is 58 years (ranges 45-73 years for men and 55- 73 years for women). The participants are 89% white, 7% Hispanic, and 3% black.

CONCLUSION

Results from AFCAPS/TexCAPS will be applicable to large segments of populations; in the USA alone, eight million share the demographic and baseline-lipid-level characteristics of the study cohort.

Gastrointestinal health care resource use and costs associated with nonsteroidal antiinflammatory drugs versus acetaminophen: retrospective cohort study of an elderly population

OBJECTIVE

To estimate gastrointestinal (GI) health care resource use and direct costs associated with prescription nonsteroidal antiinflammatory drugs (NSAIDs) in an elderly population.

METHODS

Using the Government of Quebec's health insurance database, we obtained the medical, pharmaceutical, and demographic records of 73,850 senior citizens who, between 1993 and 1997, had either an NSAID or an acetaminophen prescription dispensed. The date of their first dispensed prescription for an NSAID or acetaminophen was termed their index date. Patients who were not taking oral corticosteroids or anticoagulants at their index date, were not diagnosed with cancer at their index date, and were not hospitalized and did not have any GI events during the year prior to their index date were included in the study. Patients who had a dispensed NSAID prescription at their index date formed the NSAID cohort; the others formed the acetaminophen cohort. All patients were followed up for 2 years. The daily direct costs of GI events incurred during NSAID therapy by the NSAID cohort were compared with those incurred during a similar followup period by the acetaminophen cohort. The difference in these average daily costs was attributed to NSAID use.

RESULTS

The NSAID cohort included 5,268 senior citizens and the acetaminophen cohort 2,245. More GI adverse events were observed in the NSAID cohort (odds ratio 2.48, 95% confidence interval 2.06, 3.00). The average daily direct cost of GI events for a day of NSAID therapy attributed to the NSAIDs was $0.84 (Canadian). On average, for each Canadian dollar spent on NSAIDs, an additional $0.66 was spent on their side effects.

CONCLUSION

Safer alternatives to NSAIDs would significantly reduce medical care costs for patients in need of NSAID therapy.

Relation between baseline and on-treatment lipid parameters and first acute major coronary events in the Air Force/Texas Coronary Atherosclerosis Prevention Study (AFCAPS/TexCAPS)

BACKGROUND

The Air Force/Texas Coronary Atherosclerosis Prevention Study (AFCAPS/TexCAPS) is the first primary-prevention study in a cohort with average total cholesterol (TC) and LDL cholesterol (LDL-C) and below-average HDL cholesterol (HDL-C). Treatment with lovastatin (20 to 40 mg/d) resulted in a 25% reduction in LDL-C and a 6% increase in HDL-C, as well as a 37% reduction in risk for first acute major coronary event (AMCE), defined as fatal or nonfatal myocardial infarction, unstable angina, or sudden cardiac death. This article describes the relation between baseline and on-treatment lipid and apolipoprotein (apo) parameters and subsequent risk for AMCEs.

METHODS AND RESULTS

With all available data from the entire 6605-patient cohort, a prespecified Cox backward stepwise regression model identified outcome predictors, and logistic regression models examined the relation between lipid variables and AMCE risk. Baseline LDL-C, HDL-C, and apoB were significant predictors of AMCE; only on-treatment apoB and the ratio of apoB to apoAI were predictive of subsequent risk; on-treatment LDL-C was not. When event rates were examined across tertiles of baseline lipids, a consistent benefit of treatment with lovastatin was observed.

CONCLUSIONS

Persons with average TC and LDL-C levels and below-average HDL-C may obtain significant clinical benefit from primary-prevention lipid modification. On-treatment apoB, especially when combined with apoAI to form the apoB/AI ratio, may be a more accurate predictor than LDL-C of risk for first AMCE.

Adverse upper gastrointestinal effects of rofecoxib compared with NSAIDs

CONTEXT

Nonsteroidal anti-inflammatory drug (NSAID)-induced gastrointestinal (GI) toxic effects, such as upper GI tract perforations, symptomatic gastroduodenal ulcers, and upper GI tract bleeding (PUBs), are thought to be attributable to cyclooxygenase 1 (COX-1) inhibition. Rofecoxib specifically inhibits COX-2 and has demonstrated a low potential for causing upper GI injury.

OBJECTIVE

To compare the incidence of PUBs in patients with osteoarthritis treated with rofecoxib vs NSAIDs.

DESIGN

Prespecified analysis of all 8 double-blind, randomized phase 2b/3 rofecoxib osteoarthritis trials conducted from December 1996 through March 1998, including one 6-week dose-ranging study, two 6-week efficacy studies vs ibuprofen and placebo, two 1-year efficacy studies vs diclofenac, two 6-month endoscopy studies vs ibuprofen and placebo, and one 6-week efficacy study vs nabumetone and placebo.

SETTING

Multinational sites. Participants Osteoarthritis patients (N = 5435; mean age, 63 years [range, 38-94 years]; 72.9% women).

INTERVENTIONS

Rofecoxib, 12.5, 25, or 50 mg/d (n = 1209, 1603, and 545, respectively, combined) vs ibuprofen, 800 mg 3 times per day (n = 847), diclofenac, 50 mg 3 times per day (n = 590); or nabumetone, 1500 mg/d (n = 127) (combined).

MAIN OUTCOME MEASURE

Cumulative incidence of PUBs for rofecoxib vs NSAIDs, based on survival analysis of time to first PUB diagnosis, using PUBs that met pre-specified criteria judged by a blinded, external adjudication committee.

RESULTS

The incidence of PUBs over 12 months was significantly lower with rofecoxib vs NSAIDs (12-month cumulative incidence, 1.3% vs 1.8%; P = .046; rate per 100 patient-years, 1.33 vs 2.60; relative risk, 0.51; 95% confidence interval, 0.26-1.00). The cumulative incidence of dyspeptic GI adverse experiences was also lower with rofecoxib vs NSAIDS over 6 months (23.5% vs 25.5%; P = .02), after which the incidence rates converged.

CONCLUSION

In a combined analysis of 8 trials of patients with osteoarthritis, treatment with rofecoxib was associated with a significantly lower incidence of PUBs than treatment with NSAIDs.

Effects of the amyloid precursor protein Glu693-->Gln 'Dutch' mutation on the production and stability of amyloid beta-protein

Hereditary cerebral haemorrhage with amyloidosis, Dutch type (HCHWA-D), is a cerebral amyloidosis characterized by prominent vascular deposits and fatal haemorrhages. The disorder is caused by a point mutation in codon 693 of the gene encoding the amyloid precursor protein (APP), resulting in a Glu-->Gln amino acid substitution at position 22 of the amyloid beta-protein (Abeta) region. The pathogenetic mechanisms of HCHWA-D are unknown but could involve alterations in the proteolytic processing of APP and in amyloid fibril formation. We examined Abeta production and stability by using cultured human embryonic kidney 293 cells stably expressing wild-type or 'Dutch' APP. Radiosequencing and quantitative immunoprecipitation experiments showed that cells expressing Dutch APP secreted increased quantities of Abeta peptides beginning at Asp1, and of truncated peptides beginning at Val18 and Phe19. The ratio of levels of 4 kDa (Abeta) to 3 kDa (p3) peptides remained constant due to co-ordinate decreases in other peptide species. Novel truncated or elongated peptides were not observed. Pulse-chase experiments showed that the Dutch mutation did not affect the stability of the Abeta or p3 populations. These results are consistent with a disease process in which the Dutch mutation results in the production of Abeta peptides with enhanced propensities for fibrillogenesis, leading to accelerated vascular deposition and disease.

Comparison of the responsiveness and relative effect size of the western Ontario and McMaster Universities Osteoarthritis Index and the short-form Medical Outcomes Study Survey in a randomized, clinical trial of osteoarthritis patients

OBJECTIVE

This study compares the responsiveness and relative effect sizes of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) with the Medical Outcomes Study Short Form Health Survey (SF-36) in a randomized clinical trial for treatment of osteoarthritis (OA).

METHODS

Patients with OA of the knee or hip were randomized to receive either placebo or 2,400 mg/day of ibuprofen for 28 days. Patients completed the WOMAC and SF-36 at baseline and days 7, 14, and 28 of the trial.

RESULTS

Patients receiving ibuprofen showed significant improvement in WOMAC pain, physical functioning, and the total score, while improvement was detected only for bodily pain on the SF-36. The WOMAC detected significant differences between ibuprofen and placebo for pain and physical functioning, whereas the SF-36 detected differences for the bodily pain subscale.

CONCLUSION

These results suggest the WOMAC has greater power to detect treatment differences than the SF-36, with respect to pain and physical functioning, in OA clinical trials.

Diabetes mellitus and its complications in an African-American community: project DIRECT

Project DIRECT (Diabetes Intervention Reaching and Educating Communities Together) is a multilevel community-based intervention project designed to address diabetes and its complications in an African-American community. This article presents results of the Project DIRECT pilot study and describes risk factors for diabetes, diabetes prevalence, complications, and care practices. During 1993, a pilot study was conducted among persons 20 to 74 years of age in Wake County, North Carolina. The study involved household interviews and examinations, and more extensive health center interviews and examinations based on the race of the head of the household, previous diagnosis of diabetes, and results of capillary glucose tests done in the household. Of the black population aged 20 to 74 years, 52 +/- 3% reported being inactive and 51 +/- 3% were overweight; the prevalence of diagnosed diabetes was 5.2 +/- 0.9%; the prevalence of undiagnosed diabetes was 5.7 +/- 2.7%; and the prevalence of impaired glucose tolerance was 11.4 +/- 7.5%. Blacks with diabetes were significantly more likely than nonblacks with diabetes to have uncontrolled hypertension and to smoke cigarettes. Blacks with diabetes were significantly less likely to report having health insurance or to have a private health-care provider. Diabetes mellitus is a major public health problem in the African-American community of Wake County. Modifiable risk factors for diabetes and undiagnosed diabetes are common. Project DIRECT is attempting to improve the health-related quality of life of this population by reducing the burden of diabetes and its complications through a multilevel, community-based intervention.

Heparin-binding properties of the amyloidogenic peptides Abeta and amylin. Dependence on aggregation state and inhibition by Congo red

Aggregation and deposition of the 40-42-residue amyloid beta-protein (Abeta) are early and necessary neuropathological events in Alzheimer's disease. An understanding of the molecular interactions that trigger these events is important for therapeutic strategies aimed at blocking Abeta plaque formation at the earliest stages. Heparan sulfate proteoglycans may play a fundamental role since they are invariably associated with Abeta and other amyloid deposits at all stages. However, the nature of the Abeta-heparan sulfate proteoglycan binding has been difficult to elucidate because of the strong tendency of Abeta to self-aggregate. Affinity co-electrophoresis can measure the binding of proteoglycans or glycosaminoglycans to proteins without altering the physical state of the protein during the assay. We used affinity co-electrophoresis to study the interaction between Abeta and the glycosaminoglycan heparin and found that the aggregation state of Abeta governs its heparin-binding properties: heparin binds to fibrillar but not nonfibrillar Abeta. The amyloid binding dye, Congo red, inhibited the interaction in a specific and dose-dependent manner. The "Dutch" mutant AbetaE22Q peptide formed fibrils more readily than wild type Abeta and it also attained a heparin-binding state more readily, but, once formed, mutant and wild type fibrils bound heparin with similar affinities. The heparin-binding ability of aggregated AbetaE22Q was reversible with incubation in a solvent that promotes alpha-helical conformation, further suggesting that conformation of the peptide is important. Studies with another human amyloidogenic protein, amylin, suggested that its heparin-binding properties were also dependent on aggregation state. These results demonstrate the dependence of the Abeta-heparin interaction on the conformation and aggregation state of Abeta rather than primary sequence alone, and suggest methods of interfering with this association.

Ritodrine- and terbutaline-induced hypokalemia in preterm labor: mechanisms and consequences

The effects of ritodrine and terbutaline on potassium homeostasis, renal function, and cardiac rhythm were assessed in women treated with these drugs for preterm labor. Timed blood and urine samples were obtained for two hours before and during six hours of intravenous ritodrine (N = 5) and terbutaline (N = 5) administered in pharmacologically equivalent doses. No differences were found in any parameters affecting potassium homeostasis or renal function between these drugs. A decrease in mean plasma potassium of 0.9 mEq/liter occurred after 30 minutes of drug infusion (4.2 +/- 0.1 to 3.3 +/- 0.1 mEq/liter, P < 0.005) before any significant changes in plasma glucose (75.0 +/- 4.7 to 93.7 +/- 6.1 mg/dl, P = NS) or plasma insulin (12.4 +/- 6.0 to 28.4 +/- 5.1 mU/ml, P = NS). The mean plasma potassium after four hours of drug infusion was 2.5 +/- 0.1 mEq/liter. Plasma insulin rose to a level known to induce cellular potassium uptake (39.2 +/- 7.7 mU/ml) after 60 minutes of drug therapy and remained at this level for four hours. Hyperlactatemia occurred at four hours (4.7 +/- 0.8 mmol/liter) and the plasma lactate/pyruvate ratio increased in a 10:1 ratio. Both drugs significantly reduced glomerular filtration rate, sodium, potassium, and chloride excretion and urinary flow rate. Changes in acid-base homeostasis, plasma aldosterone, or renal potassium excretion did not contribute to ritodrine-or terbutaline-induced hypokalemia. In 83 women with preterm labor randomly assigned to ritodrine (N = 42) or terbutaline (N = 41), the maximum decrease in plasma potassium occurred after six hours of drug infusion. During Holter monitoring, 3 of 14 women treated with ritodrine or terbutaline developed symptomatic cardiac arrhythmias at the lowest plasma potassium while no women treated with saline and morphine (N = 12) developed cardiac arrhythmias (P = 0.14). We conclude that ritodrine and terbutaline induce profound hypokalemia by stimulating cellular potassium uptake and both drugs cause significant renal sodium and fluid retention and cardiac arrhythmias. Careful monitoring of electrolytes, fluid balance, and cardiac rhythm should occur during tocolytic therapy with ritodrine or terbutaline.

Timing of hard palatal closure: a critical long-term analysis

The controversy about timing of cleft palate surgical procedures is focused on early palatoplasty for improved speech versus delayed hard palate repair for undisturbed facial growth. Timing and technique of palate repair are the most important influences on speech and facial growth, yet there is no consensus on the age or technique for surgery. The Oxford Cleft Palate Study was initiated to evaluate critically the long-term follow-up of 44 patients with early versus late closure of the hard palate. A multidisciplinary approach was used to determine the incidence of speech deficiencies, palatal fistulas, maxillofacial growth disturbances, and hearing abnormalities and to assess objectively the long-term effects of two different treatment modalities on the cleft palate patient. The 44 patients were selected randomly, interviewed, and examined by the multidisciplinary Oxford Cleft Palate Study team. The average age at follow-up in the early closure group was 17.0 years versus 18.2 years in the late closure group. There was a similar number of unilateral and bilateral clefts in both the early and late closure groups. The hard palate was closed in the early group at an average age of 10.8 months versus 48.6 months in the late closure group. All operative procedures in each group were performed by the same senior plastic surgery consultant. Both consultants have since retired and did not participate in the study. Each patient was evaluated by the same plastic surgeon, speech pathologist, orthodontist, and otologist. All examiners were blinded in that they were unaware of the type or timing of the surgical technique and had no prior knowledge of or access to the patient's medical records. Furthermore, none of the examiners participated in the initial care and surgery of these patients. Statistically significant greater speech deficiencies were noted with delayed hard palate closure, especially in articulation, nasal resonance, intelligibility, and substitution pattern assessment (overall intelligibility, p < 0.01). Likewise, the persistent palatal fistula rate in the late closure group was 35 percent in comparison with 5 percent for the early closure group (p <0.02). No significant differences in hearing or maxillofacial growth impairment were delineated in either group. Our data suggest that delaying hard palate closure results in significant speech impairment without a beneficial maxillofacial growth response.