Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)

Control of the unidirectional motor in Rhodobacter sphaeroides

The control of the flagellar motor in Rhodobacter sphaeroides was investigated. Unlike most flagellar motors which are controlled by reversing the direction of rotation, the R. sphaeroides motor is controlled via a stop-start mechanism. Advanced optical microscopy was employed alongside genetic, biochemical, and behavioural techniques.High-resolution measurements of rotating beads on flagellar stubs revealed that the R. sphaeroides motor is similar to its E. coli counterpart, rotating counterclockwise at comparable torques/speeds (1,300 pNnm/rad at stall torque), and exhibiting transient step changes in speed. The mean stop duration, mean stop frequency (number of stops per s), and run bias (fraction of time spent rotating) of wild-type at steady-state were 0.66 ± 1.01 s, 0.31 ± 0.19 s-1, and 0.80 ± 0.20, respectively.Manipulating signal inputs to the motor genetically, or by exposing cells to chemotactic stimuli revealed that (i) without chemotactic stimulation the motor rotates continuously, (ii) phosphorylated CheYs are required to stop the motor, and (iii) the chemotaxis system cannot control the speed of rotation of the motor (termed chemokinesis) as previously reported. Complementation studies revealed that CheY3, CheY4, and CheY5 are functionally equivalent. The copy numbers per cell of important CheYs were found to vary greatly under the conditions tested (To determine how CheY-P binding causes the motor to stop, external force (viscous flow or optical tweezers) was applied to chemotactically stopped motors. CheY-P binding might either cause the torque-generating units to disengage from the rotor, analogous to a clutch, or trigger the rotor to jam, analogous to a brake. The rotor resisted re-orientation during a chemotactic stop implying that the motor was held in a locked state. The value of torque resisting forward motion (keeping it locked) was estimated to be 2-3 x stall torque (2,500-4,000 pNnm/rad).Furthermore beads attached to flagellar stubs stop at fixed angles for several seconds, showing no large-scale Brownian motion. Step analysis revealed that these stop events occur at 27-28 discrete angles around the motor, which most likely reflect the periodicity of the rotor (i.e. copies of FliG). This represents the first experimental resolution of steps in the rotation of a wild-type bacterial flagellar motor with a full complement of torque-generating units.</p

A molecular brake, not a clutch, stops the Rhodobacter sphaeroides flagellar motor

Many bacterial species swim by employing ion-driven molecular motors that power the rotation of helical filaments. Signals are transmitted to the motor from the external environment via the chemotaxis pathway. In bidirectional motors, the binding of phosphorylated CheY (CheY-P) to the motor is presumed to instigate conformational changes that result in a different rotor-stator interface, resulting in rotation in the alternative direction. Controlling when this switch occurs enables bacteria to accumulate in areas favorable for their survival. Unlike most species that swim with bidirectional motors, Rhodobacter sphaeroides employs a single stop-start flagellar motor. Here, we asked, how does the binding of CheY-P stop the motor in R. sphaeroides—using a clutch or a brake? By applying external force with viscous flow or optical tweezers, we show that the R. sphaeroides motor is stopped using a brake. The motor stops at 27–28 discrete angles, locked in place by a relatively high torque, approximately 2–3 times its stall torque

Inducible-Expression Plasmid for Rhodobacter sphaeroides and Paracoccus denitrificans▿ †

We have developed a stable isopropyl-β-d-thiogalactopyranoside (IPTG)-inducible-expression plasmid, pIND4, which allows graduated levels of protein expression in the alphaproteobacteria Rhodobacter sphaeroides and Paracoccus denitrificans. pIND4 confers kanamycin resistance and combines the stable replicon of pMG160 with the lacIq gene from pYanni3 and the lac promoter, PA1/04/03, from pJBA24