Cucurbitacins Elicit Anti-Platelet Activity via Perturbation of the Cytoskeleton and Integrin Function.

Cucurbitacins are dietary compounds that have been shown to elicit a range of anti-tumour, anti-inflammatory and anti-atherosclerotic activities. Originally identified as signal transducer and activator of transcription, STAT, inhibitors, a variety of mechanisms of action have since been described, including dysregulation of the actin cytoskeleton and disruption of integrin function. Integrin outside-in signalling and cytoskeletal rearrangements are critical for the propagation of stable thrombus formation and clot retraction following platelet adhesion at the site of vessel damage. The effects of cucurbitacins on platelet function and thrombus formation are unknown. We report for the first time anti-platelet and anti-thrombotic effects of cucurbitacins B, E and I in human platelets. Treatment of platelets with cucurbitacins resulted in attenuation of platelet aggregation, secretion and fibrinogen binding following stimulation by platelet agonists. Cucurbitacins were also found to potently inhibit other integrin- and cytoskeleton-mediated events, including adhesion, spreading and clot retraction. Further investigation of cytoskeletal dynamics found treatment with cucurbitacins altered cofilin phosphorylation, enhanced activation and increased F actin polymerisation and microtubule assembly. Disruption to cytoskeletal dynamics has been previously shown to impair integrin activation, platelet spreading and clot retraction. Anti-platelet properties of cucurbitacins were found to extend to a disruption of stable thrombus formation, with an increase in thrombi instability and de-aggregation under flow. Our research identifies novel, anti-platelet and anti-thrombotic actions of cucurbitacins that appear to be linked to dysregulation of cytoskeletal dynamics and integrin function.

Atmospheric conditions and composition that influence PM2.5 oxidative potential in Beijing, China.

Epidemiological studies have consistently linked exposure to PM2.5 with adverse health effects. The oxidative potential (OP) of aerosol particles has been widely suggested as a measure of their potential toxicity. Several acellular chemical assays are now readily employed to measure OP; however, uncertainty remains regarding the atmospheric conditions and specific chemical components of PM2.5 that drive OP. A limited number of studies have simultaneously utilised multiple OP assays with a wide range of concurrent measurements and investigated the seasonality of PM2.5 OP. In this work, filter samples were collected in winter 2016 and summer 2017 during the atmospheric pollution and human health in a Chinese megacity campaign (APHH-Beijing), and PM2.5 OP was analysed using four acellular methods: ascorbic acid (AA), dithiothreitol (DTT), 2,7-dichlorofluorescin/hydrogen peroxidase (DCFH) and electron paramagnetic resonance spectroscopy (EPR). Each assay reflects different oxidising properties of PM2.5, including particle-bound reactive oxygen species (DCFH), superoxide radical production (EPR) and catalytic redox chemistry (DTT/AA), and a combination of these four assays provided a detailed overall picture of the oxidising properties of PM2.5 at a central site in Beijing. Positive correlations of OP (normalised per volume of air) of all four assays with overall PM2.5 mass were observed, with stronger correlations in winter compared to summer. In contrast, when OP assay values were normalised for particle mass, days with higher PM2.5 mass concentrations (µgm-3) were found to have lower mass-normalised OP values as measured by AA and DTT. This finding supports that total PM2.5 mass concentrations alone may not always be the best indicator for particle toxicity. Univariate analysis of OP values and an extensive range of additional measurements, 107 in total, including PM2.5 composition, gas-phase composition and meteorological data, provided detailed insight into the chemical components and atmospheric processes that determine PM2.5 OP variability. Multivariate statistical analyses highlighted associations of OP assay responses with varying chemical components in PM2.5 for both mass- and volume-normalised data. AA and DTT assays were well predicted by a small set of measurements in multiple linear regression (MLR) models and indicated fossil fuel combustion, vehicle emissions and biogenic secondary organic aerosol (SOA) as influential particle sources in the assay response. Mass MLR models of OP associated with compositional source profiles predicted OP almost as well as volume MLR models, illustrating the influence of mass composition on both particle-level OP and total volume OP. Univariate and multivariate analysis showed that different assays cover different chemical spaces, and through comparison of mass- and volume-normalised data we demonstrate that mass-normalised OP provides a more nuanced picture of compositional drivers and sources of OP compared to volume-normalised analysis. This study constitutes one of the most extensive and comprehensive composition datasets currently available and provides a unique opportunity to explore chemical variations in PM2.5 and how they affect both PM2.5 OP and the concentrations of particle-bound reactive oxygen species.

Is the Writing on the Wall for Current Medical Oaths? A Brief Historical Review of Oath Taking at Medical Schools.

Oaths recited in medical schools provide valuable insight into the medical profession's evolving core of ethical commitments. This study presents a brief overview of medical oaths, and how they came to attain their current prominence. The authors examine medical oaths used in twentieth-century North America (the USA and Canada) through a critical review of six studies on oath administration and content that were undertaken between 1928 and 2004. While oath-taking became almost universally prevalent in twentieth-century North American medical schools, the ethical content of oaths grew increasingly heterogeneous. The findings challenge assumptions about the content of medical oaths. They also create dynamic markers for gauging the variability in the current ethical milieus of medical education, providing a basis for evaluating future direction.

Financial Vulnerability of Dairy Farms Challenged by Johne's Disease to Changes in Farm Payment Support.

Johne's disease is an endemic contagious bacterial infection of ruminants which is prevalent in the United Kingdom and elsewhere. It can lower financial returns on infected farms by reducing farm productivity through output losses and control expenditures. A farm-level analysis of the economics of the disease was conducted taking account of farm variability and different disease prevalence levels. The aim was to assess the financial impacts of a livestock disease on farms and determine their financial vulnerability if farm support payments were to be removed under future policy reforms. A farm-level optimization model, ScotFarm, was used on 50 Scottish dairy farms taken from the Farm Business Survey to determine the impacts of the disease. A counterfactual comparison of five alternative "disease" scenarios with a "no-disease" scenario was carried out to evaluate economic impact of the disease. The extent of a farm's reliance on direct support payments was considered to be an indicator of their financial vulnerability. Under this definition, farms were grouped into three financial vulnerability risk categories; "low risk," "medium risk," and "high risk" farms. Results show that farms are estimated to incur a loss of 32% on average of their net profit under a standard disease prevalence level. Farms in the "low risk" and "medium risk" categories were estimated to have a lower financial impact of the disease (22 and 28% reduction on farm net profit, respectively) which, along with their lower reliance on farm direct support payments, indicate they would be more resilient to the disease under future changes in farm payment support. On the contrary, farms in the "high risk" category were estimated to have a reduction of 50% on their farm net profit. A majority of these farms (61%) in the "high risk" category move from being profitable to loss making under the standard disease scenario when farm support payments are removed. Of these, 15% do so because of the impact of the disease. These farms will be more vulnerable if changes were to be made in farm support payments under future agricultural policy reforms.

Molecular Basis of Altered hERG1 Channel Gating Induced by Ginsenoside Rg3.

Outward current conducted by human ether-à-go-go-related gene type 1 (hERG1) channels is a major determinant of action potential repolarization in the human ventricle. Ginsenoside 20(S)-Rg3 [Rg3; (2S,3R,4S,5S,6R)-2-[(2R,3R,4S,5S,6R)-4,5-dihydroxy-2-[[(3S,5R,8R,9R,10R,12R,13R,14R,17S)-12-hydroxy-17-[(2S)-2-hydroxy-6-methylhept-5-en-2-yl]-4,4,8,10,14-pentamethyl-2,3,5,6,7,9,11,12,13,15,16,17-dodecahydro-1H-cyclopenta[a]phenanthren-3-yl]oxy]-6-(hydroxymethyl)oxan-3-yl]oxy-6-(hydroxymethyl)oxane-3,4,5-triol], an alkaloid isolated from the root of Panax ginseng, slows the rate of hERG1 deactivation, induces channels to open at more negative potentials than normal, and increases current magnitude. The onset of Rg3 action is extremely fast, suggesting that it binds to an extracellular accessible site on the channel to alter its gating. Here we used a scanning mutagenesis approach to identify residues in the extracellular loops and transmembrane segments of hERG1 that might interact with Rg3. Single or multiple residues of hERG1 were mutated to Ala or Cys and the resulting mutant channels were heterologously expressed in Xenopus oocytes. The effects of Rg3 on the voltage dependence of activation and the deactivation rate of mutant channel currents were characterized using the two-microelectrode voltage clamp technique. Mutation to Ala of specific residues in the S1 (Tyr420), S2 (Leu452, Phe463), and S4 (Ile521, Lys525) segments partially inhibited the effects of Rg3 on hERG1. The double mutant Y420A/L452A nearly eliminated the effects of Rg3 on voltage-dependent channel gating but did not prevent the increase in current magnitude. These findings together with molecular modeling suggest that Rg3 alters the gating of hERG1 channels by interacting with and stabilizing the voltage sensor domain in an activated state.

Restoration of mutant bestrophin-1 expression, localisation and function in a polarised epithelial cell model.

Autosomal recessive bestrophinopathy (ARB) is a retinopathy caused by mutations in the bestrophin-1 protein, which is thought to function as a Ca2+-gated Cl- channel in the basolateral surface of the retinal pigment epithelium (RPE). Using a stably transfected polarised epithelial cell model, we show that four ARB mutant bestrophin-1 proteins were mislocalised and subjected to proteasomal degradation. In contrast to the wild-type bestrophin-1, each of the four mutant proteins also failed to conduct Cl- ions in transiently transfected cells as determined by whole-cell patch clamp. We demonstrate that a combination of two clinically approved drugs, bortezomib and 4-phenylbutyrate (4PBA), successfully restored the expression and localisation of all four ARB mutant bestrophin-1 proteins. Importantly, the Cl- conductance function of each of the mutant bestrophin-1 proteins was fully restored to that of wild-type bestrophin-1 by treatment of cells with 4PBA alone. The functional rescue achieved with 4PBA is significant because it suggests that this drug, which is already approved for long-term use in infants and adults, might represent a promising therapy for the treatment of ARB and other bestrophinopathies resulting from missense mutations in BEST1.

Identification of the Intracellular Na+ Sensor in Slo2.1 Potassium Channels.

Slo2 potassium channels have a very low open probability under normal physiological conditions, but are readily activated in response to an elevated [Na(+)]i (e.g. during ischemia). An intracellular Na(+) coordination motif (DX(R/K)XXH) was previously identified in Kir3.2, Kir3.4, Kir5.1, and Slo2.2 channel subunits. Based loosely on this sequence, we identified five potential Na(+) coordination motifs in the C terminus of the Slo2.1 subunit. The Asp residue in each sequence was substituted with Arg, and single mutant channels were heterologously expressed in Xenopus oocytes. The Na(+) sensitivity of each of the mutant channels was assessed by voltage clamp of oocytes using micropipettes filled with 2 M NaCl. Wild-type channels and four of the mutant Slo2.1 channels were rapidly activated by leakage of NaCl solution into the cytoplasm. D757R Slo2.1 channels were not activated by NaCl, but were activated by the fenamate niflumic acid, confirming their functional expression. In whole cell voltage clamp recordings of HEK293 cells, wild-type but not D757R Slo2.1 channels were activated by a [NaCl]i of 70 mM. Thus, a single Asp residue can account for the sensitivity of Slo2.1 channels to intracellular Na(+). In excised inside-out macropatches of HEK293 cells, activation of wild-type Slo2.1 currents by 3 mM niflumic acid was 14-fold greater than activation achieved by increasing [NaCl]i from 3 to 100 mM. Thus, relative to fenamates, intracellular Na(+) is a poor activator of Slo2.1.

Assessment of soybean injury from glyphosate using airborne multispectral remote sensing.

BACKGROUND: Glyphosate drift onto off-target sensitive crops can reduce growth and yield and is of great concern to growers and pesticide applicators. Detection of herbicide injury using biological responses is tedious, so more convenient and rapid detection methods are needed. The objective of this research was to determine the effects of glyphosate on biological responses of non-glyphosate-resistant (non-GR) soybean and to correlate vegetation indices (VIs) derived from aerial multispectral imagery. RESULTS: Plant height, shoot dry weight and chlorophyll (CHL) content decreased gradually with increasing glyphosate rate, regardless of weeks after application (WAA). Accordingly, soybean yield decreased by 25% with increased rate from 0 to 0.866 kg AI ha(-1) . Similarly to biological responses, the VIs derived from aerial imagery - normalized difference vegetation index, soil adjusted vegetation index, ratio vegetation index and green NDVI - also decreased gradually with increasing glyphosate rate, regardless of WAA. CONCLUSION: The VIs were highly correlated with plant height and yield but poorly correlated with CHL, regardless of WAA. This indicated that indices could be used to determine soybean injury from glyphosate, as indicated by the difference in plant height, and to predict the yield reduction due to crop injury from glyphosate.

Concerted all-or-none subunit interactions mediate slow deactivation of human ether-à-go-go-related gene K+ channels.

During the repolarization phase of a cardiac action potential, hERG1 K(+) channels rapidly recover from an inactivated state then slowly deactivate to a closed state. The resulting resurgence of outward current terminates the plateau phase and is thus a key regulator of action potential duration of cardiomyocytes. The intracellular N-terminal domain of the hERG1 subunit is required for slow deactivation of the channel as its removal accelerates deactivation 10-fold. Here we investigate the stoichiometry of hERG1 channel deactivation by characterizing the kinetic properties of concatenated tetramers containing a variable number of wild-type and mutant subunits. Three mutations known to accelerate deactivation were investigated, including R56Q and R4A/R5A in the N terminus and F656I in the S6 transmembrane segment. In all cases, a single mutant subunit induced the same rapid deactivation of a concatenated channel as that observed for homotetrameric mutant channels. We conclude that slow deactivation gating of hERG1 channels involves a concerted, fully cooperative interaction between all four wild-type channel subunits.

Glyphosate-resistant and glyphosate-susceptible Palmer amaranth (Amaranthus palmeri S. Wats.): hyperspectral reflectance properties of plants and potential for classification.

BACKGROUND: Palmer amaranth (Amaranthus palmeri S. Wats.) is a troublesome agronomic weed in the southern United States, and several populations have evolved resistance to glyphosate. This paper reports on spectral signatures of glyphosate-resistant (GR) and glyphosate-sensitive (GS) plants, and explores the potential of using hyperspectral sensors to distinguish GR from GS plants. RESULTS: GS plants have higher light reflectance in the visible region and lower light reflectance in the infrared region of the spectrum compared with GR plants. The normalized reflectance spectrum of the GR and GS plants had best separability in the 400-500 nm, 650-690 nm, 730-740 nm and 800-900 nm spectral regions. Fourteen wavebands from within or near these four spectral regions provided a classification of unknown set of GR and GS plants, with a validation accuracy of 94% for greenhouse-grown plants and 96% for field-grown plants. CONCLUSIONS: GR and GS Palmer amaranth plants have unique hyperspectral reflectance properties, and there are four distinct regions of the spectrum that can separate the GR from GS plants. These results demonstrate that hyperspectral imaging has potential application to distinguish GR from GS Palmer amaranth plants (without a glyphosate treatment), with future implications for glyphosate resistance management. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Hair cortisol as a biomarker of stress among a first nation in Canada.

BACKGROUND: Cortisol level in hair is increasingly being used as a biomarker of chronic stress. Members of First Nation communities in Canada are experiencing stress related to a higher incidence of chronic diseases, socioeconomic factors, the state of their environment, and cultural oppression. This study aimed to investigate hair cortisol as a biomarker of stress in this population. MATERIALS AND METHODS: Hair samples were collected from the posterior vertex of 55 Walpole Island First Nation (WIFN) volunteers and compared with white volunteers living in and around London, ON, Canada. An enzyme-linked immunosorbent assay technique was used to measure cortisol content in 1 cm of hair, considered to represent 1 month of growth. In parallel, the Perceived Stress Scale (PSS), which measures short-term stress, was also completed. RESULTS: Median hair cortisol level (range) in WIFN volunteers was 177 (93-273) ng/g, significantly higher than the median hair cortisol in the healthy white controls of 116 (26-204) ng/g (P < 0.0001, Mann-Whitney U test). Hair cortisol correlated positively with gender, smoking status, and self-reported diabetes. Unlike hair cortisol, the Perceived Stress Scale did not differentiate between the First Nation and control population. CONCLUSIONS: The increased hair cortisol concentrations among WIFN volunteers compared with volunteers from a non-First Nation community suggests higher levels of chronic stress. The causes for this apparent increased stress are likely due to factors such as socioeconomic and poorer health and are worthy of further evaluation. The results highlight the difference between acute stress measured for short periods of time compared with chronic stress, measured by hair analysis.

Mechanistic insight into human ether-à-go-go-related gene (hERG) K+ channel deactivation gating from the solution structure of the EAG domain.

Human ether-à-go-go-related gene (hERG) K(+) channels have a critical role in cardiac repolarization. hERG channels close (deactivate) very slowly, and this is vital for regulating the time course and amplitude of repolarizing current during the cardiac action potential. Accelerated deactivation is one mechanism by which inherited mutations cause long QT syndrome and potentially lethal arrhythmias. hERG deactivation is highly dependent upon an intact EAG domain (the first 135 amino acids of the N terminus). Importantly, deletion of residues 2-26 accelerates deactivation to a similar extent as removing the entire EAG domain. These and other experiments suggest the first 26 residues (NT1-26) contain structural elements required to slow deactivation by stabilizing the open conformation of the pore. Residues 26-135 form a Per-Arnt-Sim domain, but a structure for NT1-26 has not been forthcoming, and little is known about its site of interaction on the channel. In this study, we present an NMR structure for the entire EAG domain, which reveals that NT1-26 is structurally independent from the Per-Arnt-Sim domain and contains a stable amphipathic helix with one face being positively charged. Mutagenesis and electrophysiological studies indicate that neutralizing basic residues and breaking the amphipathic helix dramatically accelerate deactivation. Furthermore, scanning mutagenesis and molecular modeling studies of the cyclic nucleotide binding domain suggest that negatively charged patches on its cytoplasmic surface form an interface with the NT1-26 domain. We propose a model in which NT1-26 obstructs gating motions of the cyclic nucleotide binding domain to allosterically stabilize the open conformation of the pore.

Relationship between hair cortisol concentrations and depressive symptoms in patients with coronary artery disease.

OBJECTIVE: Concentrations of cortisol in hair, a novel marker of longer-term cortisol status, were compared in depressed versus nondepressed patients with coronary artery disease (CAD). METHODS: 20 mg hair samples of 3 cm length were collected from 121 patients attending a cardiac rehabilitation program, 34 of whom suffered from depressive symptoms. RESULTS: Controlling for age, gender, coronary artery bypass grafting, history of depression, and time since most recent acute coronary syndrome, cortisol concentrations (P = 0.162) did not predict severity of depression. Younger age (P = 0.003) was a significant predictor of depressive symptoms. Perceived stress was not associated with long-term cortisol concentrations (P = 0.161). CONCLUSIONS: Cortisol concentrations in hair do not predict depressive symptoms in CAD patients attending cardiac rehabilitation.

Biological responses to glyphosate drift from aerial application in non-glyphosate-resistant corn.

BACKGROUND: Glyphosate drift from aerial application onto susceptible crops is inevitable, yet the biological responses to glyphosate drift in crops are not well characterized. The objectives of this research were to determine the effects of glyphosate drift from a single aerial application (18.3 m swath, 866 g AE ha(-1)) on corn injury, chlorophyll content, shikimate level, plant height and shoot dry weight in non-glyphosate-resistant (non-GR) corn. RESULTS: One week after application (WAA), corn was killed at 3 m from the edge of the spray swath, with injury decreasing to 18% at 35.4 m downwind. Chlorophyll content decreased from 78% at 6 m to 22% at 15.8 m, and it was unaffected beyond 25.6 m at 1 WAA. Shikimate accumulation in corn decreased from 349% at 0 m to 93% at 15.8 m, and shikimate levels were unaffected beyond 25.6 m downwind. Plant height and shoot dry weight decreased gradually with increasing distance. At a distance of 35.4 m, corn height was reduced by 14% and shoot dry weight by 10% at 3 WAA. CONCLUSIONS: Corn injury and other biological responses point to the same conclusion, that is, injury from glyphosate aerial drift is highest at the edge of the spray swath and decreases gradually with distance. The LD(50) (the lethal distance that drift must travel to cause a 50% reduction in biological response) ranged from 12 to 26 m among the biological parameters when wind speed was 11.2 km h(-1) and using a complement of CP-09 spray nozzles on spray aircraft.

Agronomic and environmental implications of enhanced s-triazine degradation.

Novel catabolic pathways enabling rapid detoxification of s-triazine herbicides have been elucidated and detected at a growing number of locations. The genes responsible for s-triazine mineralization, i.e. atzABCDEF and trzNDF, occur in at least four bacterial phyla and are implicated in the development of enhanced degradation in agricultural soils from all continents except Antarctica. Enhanced degradation occurs in at least nine crops and six crop rotation systems that rely on s-triazine herbicides for weed control, and, with the exception of acidic soil conditions and s-triazine application frequency, adaptation of the microbial population is independent of soil physiochemical properties and cultural management practices. From an agronomic perspective, residual weed control could be reduced tenfold in s-triazine-adapted relative to non-adapted soils. From an environmental standpoint, the off-site loss of total s-triazine residues could be overestimated 13-fold in adapted soils if altered persistence estimates and metabolic pathways are not reflected in fate and transport models. Empirical models requiring soil pH and s-triazine use history as input parameters predict atrazine persistence more accurately than historical estimates, thereby allowing practitioners to adjust weed control strategies and model input values when warranted.

Testosterone concentrations in hair of hypogonadal men with and without testosterone replacement therapy.

BACKGROUND: The measurement of testosterone (T) is essential for the diagnosis of male hypogonadism and for monitoring treatment. Samples need to be obtained at specific times in relation to the diurnal rhythm and therapeutic T injections. In this study, we explored the measurement of T in hair as an alternative method to assess gonadal status and long-term T exposure in men. SUBJECTS AND METHODS: Thirty-six male subjects comprising 17 healthy volunteers, 10 untreated hypogonadal men, and nine hypogonadal men receiving T injections were studied. T was measured in serum and in hair. T in hair was measured using a commercially available salivary T enzyme immunoassay kit adapted for this use. RESULTS: The T concentration in the hair of hypogonadal men receiving T injections was significantly higher than that in untreated hypogonadal volunteers, but not eugonadal men. Median T concentrations were 3.66 (range, 0.82-15.00), 0.94 (range, 0.33-3.68), and 1.85 (range, 0.58-3.06) pg/g hair, respectively. CONCLUSIONS: T in hair reflects gonadal status in men and may be useful for monitoring T therapy over several weeks to months in hypogonadal men.

Stress pathways to spontaneous preterm birth: the role of stressors, psychological distress, and stress hormones.

The authors investigated a large number of stressors and measures of psychological distress in a multicenter, prospective cohort study of spontaneous preterm birth among 5,337 Montreal (Canada)-area women who delivered from October 1999 to April 2004. In addition, a nested case-control analysis (207 cases, 444 controls) was used to explore potential biologic pathways by analyzing maternal plasma corticotrophin-releasing hormone (CRH), placental histopathology, and (in a subset) maternal hair cortisol. Among the large number of stress and distress measures studied, only pregnancy-related anxiety was consistently and independently associated with spontaneous preterm birth (for values above the median, adjusted odds ratio = 1.8 (95% confidence interval: 1.3, 2.4)), with a dose-response relation across quartiles. The maternal plasma CRH concentration was significantly higher in cases than in controls in crude analyses but not after adjustment (for concentrations above the median, adjusted odds ratio = 1.1 (95% confidence interval: 0.8, 1.6)). In the subgroup (n = 117) of participants with a sufficient maternal hair sample, hair cortisol was positively associated with gestational age. Neither maternal plasma CRH, hair cortisol, nor placental histopathologic features of infection/inflammation, infarction, or maternal vasculopathy were significantly associated with pregnancy-related anxiety or any other stress or distress measure. The biologic pathways underlying stress-induced preterm birth remain poorly understood.

Comparing hyperlipidemia control with daily versus twice-weekly simvastatin.

BACKGROUND: Costs associated with the use of hydroxymethylglutaryl coenzyme A reductase inhibitors are increasing. Finding ways to manage hyperlipidemia at lower costs is critical to all healthcare systems. OBJECTIVE: To assess effectiveness, safety, cost, and patients' satisfaction when converting hyperlipemic patients taking simvastatin daily to simvastatin twice weekly. METHODS: This nonrandomized, open-label, proof-of-concept study converted patients treated with simvastatin 10 or 20 mg daily to 40 or 80 mg twice weekly, respectively, for 12 weeks. The lipid profiles at enrollment, week 6, and week 12 were compared using repeated-measures ANOVA. The percentage of patients attaining the appropriate low-density lipoprotein cholesterol (LDL-C) goal was determined. RESULTS: Thirty-one patients completed the study. The proportion of patients at the LDL-C goal was not statistically different between enrollment and week 12 (87% vs 68%; p = 0.068). The mean LDL-C value +/- SD at weeks 6 and 12 increased compared with enrollment (112 +/-20, 111 +/-17, and 97 +/- 17 mg/dL, respectively; p < 0.001). Three (10%) patients reported nonadherence to the twice-weekly regimen. Seventeen (55%) patients reported that both regimens were equally convenient or preferred the twice-weekly regimen. Estimated cost-savings at our institution associated with this regimen would be $32 000 per 1000 patients per year. CONCLUSIONS: The twice-weekly regimen safely maintained most of the patients at their LDL-C goal level, and over half the patients found this regimen to be the same or easier to follow than a daily regimen. Large outcome studies evaluating this approach are needed.