Preclinical to Clinical Translation of CNS Transporter Occupancy of TD-9855, a Novel Norepinephrine and Serotonin Reuptake Inhibitor

Background:

Monoamine reuptake inhibitors exhibit unique clinical profiles that reflect distinct engagement of the central nervous system (CNS) transporters.

Methods:

We used a translational strategy, including rodent pharmacokinetic/pharmacodynamic modeling and positron emission tomography (PET) imaging in humans, to establish the transporter profile of TD-9855, a novel norepinephrine and serotonin reuptake inhibitor.

Results:

TD-9855 was a potent inhibitor of norepinephrine (NE) and serotonin 5-HT uptake in vitro with an inhibitory selectivity of 4- to 10-fold for NE at human and rat transporters. TD-9855 engaged norepinephrine transporters (NET) and serotonin transporters (SERT) in rat spinal cord, with a plasma EC₅₀ of 11.7ng/mL and 50.8ng/mL, respectively, consistent with modest selectivity for NET in vivo.Accounting for species differences in protein binding, the projected human NET and SERT plasma EC₅₀ values were 5.5ng/mL and 23.9ng/mL, respectively. A single-dose, open-label PET study (4–20mg TD-9855, oral) was conducted in eight healthy males using the radiotracers [¹¹C]-3-amino-4- [2-[(di(methyl)amino)methyl]phenyl]sulfanylbenzonitrile for SERT and [¹¹C]-(S,S)-methylreboxetine for NET. The long pharmacokinetic half-life (30–40h) of TD-9855 allowed for sequential assessment of SERT and NET occupancy in the same subject. The plasma EC₅₀ for NET was estimated to be 1.21ng/mL, and at doses of greater than 4mg the projected steady-state NET occupancy is high (>75%). After a single oral dose of 20mg, SERT occupancy was 25 (±8)% at a plasma level of 6.35ng/mL.

Conclusions:

These data establish the CNS penetration and transporter profile of TD-9855 and inform the selection of potential doses for future clinical evaluation.     

Good Functional Recovery of Complex Elbow Dislocations Treated With Hinged External Fixation: A Multicenter Prospective Study

BackgroundAfter a complex dislocation, some elbows remain unstable after closed reduction or fracture treatment. Function after treatment with a hinged external fixator theoretically allows collateral ligaments to heal without surgical reconstruction. However, there is a lack of prospective studies that assess functional outcome, pain, and ROM.Questions/purposesWe asked: (1) In complex elbow fracture-dislocations, does treatment with a hinged external fixator result in reduction of disability and pain, and in improvement in ROM, function, and quality of life? (2) Does delayed treatment (7 days or later) have a negative effect on ROM after 1 year? (3) What are the complications seen after external fixator treatment?MethodsDuring a 2-year period, 11 centers recruited 27 patients 18 years or older who were included and evaluated at 2 and 6 weeks and at 3, 6, and 12 months after surgery as part of this prospective case series. During the study period, the participating centers agreed on general indications for use of the hinged external fixator, which included persistent instability after closed reduction alone or closed reduction combined with surgical treatment of associated fracture(s), when indicated. Functional outcome was evaluated using the Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH; primary outcome) score, the Mayo Elbow Performance Index (MEPI), the Oxford Elbow Score, and the level of pain (VAS). ROM, adverse events, secondary interventions, and radiographs also were evaluated. A total of 26 of the 27 patients (96%) were available for followup at 1 year.ResultsAll functional and pain scores improved. The median QuickDASH score decreased from 30 (25^th–75^th percentiles [P₂₅–P₇₅], 23–40) at 6 weeks to 7 (P₂₅–P₇₅, 2–12) at 1 year with a median difference of −25 (p < 0.001). The median MEPI score increased from 80 (P₂₅–P₇₅, 64–85) at 6 weeks to 100 (P₂₅–P₇₅, 85–100) at 1 year with a median difference of 15 (p < 0.001). The median Oxford Elbow Score increased from 60 (P₂₅–P₇₅, 44–68) at 6 weeks to 90 (P₂₅–P₇₅, 73–96) at 1 year with a median difference of 29 (p < 0.001). The median VAS decreased from 2.8 (P₂₅–P₇₅, 1.0–5.0) at 2 weeks to 0.5 (P₂₅–P₇₅, 0.0–1.9) at 1 year with a median difference of −2.1 (p = 0.001). ROM also improved. The median flexion-extension arc improved from 50° (P₂₅–P₇₅, 33°–80°) at 2 weeks to 118° (P₂₅–P₇₅, 105°–138°) at 1 year with a median difference of 63° (p < 0.001). Similarly, the median pronation-supination arc improved from 90° (P₂₅–P₇₅, 63°–124°) to 160° (P₂₅–P₇₅, 138°–170°) with a median difference of 75° (p < 0.001). At 1 year, the median residual deficit compared with the uninjured side was 30° (P₂₅–P₇₅, 5°–35°) for the flexion-extension arc, and 3° (P₂₅–P₇₅, 0°–25°) for the pronation-supination arc. Ten patients (37%) experienced a fixator-related complication, and seven patients required secondary surgery (26%). One patient reported recurrent instability.ConclusionsA hinged external elbow fixator provides enough stability to start early mobilization after an acute complex elbow dislocation and residual instability. This was reflected in good functional outcome scores and only slight disability despite a relatively high complication rate.

Level of Evidence

Level IV, therapeutic study.     

Recombination in vitro between herpes simplex virus type 1 a sequences.

We have partially purified an activity from extracts of cells infected with herpes simplex virus type 1 that mediates recombination between repeated copies of the 317-base-pair a sequence of herpes simplex virus type 1. Recombination leads to deletion of a lacZ indicator gene situated between two directly repeated copies of the a sequence and is scored by transformation of lacZ- Escherichia coli. The two products of the reaction can be observed directly by restriction enzyme digestion and Southern blot analysis. The recombinase activity is also detectable, but at a lower level, in uninfected cell extracts. The DNA substrate must contain the two a sequences arranged in direct orientation to generate the lacZ deletion. However, when the a sequences are arranged in inverted orientation, an inversion results. A substrate with two homologous sequences of size and G + C content similar to the a sequence undergoes recombination at a much lower frequency. The reaction requires a divalent cation (Mg2+ or Mn2+) but not ATP or any other nucleoside triphosphate. The simple requirements and specificity for the a sequence suggest that the recombination may proceed by a site-specific mechanism.     

Chronic Q fever: review of the literature and a proposal of new diagnostic criteria

A review was performed to determine clinical aspects and diagnostic tools for chronic Q fever. We present a Dutch guideline based on literature and clinical experience with chronic Q fever patients in The Netherlands so far. In this guideline diagnosis is categorized as proven, possible or probable chronic infection based on serology, PCR, clinical symptoms, risk factors and diagnostic imaging.