A PDE10A inhibitor CPL500036 is a novel agent modulating striatal function devoid of most neuroleptic side-effects

Background: Phosphodiesterase 10A (PDE10A) is expressed almost exclusively in the striatum and its inhibition is suggested to offer potential treatment in disorders associated with basal ganglia. We evaluated the selectivity, cytotoxicity, genotoxicity, pharmacokinetics and potential adverse effects of a novel PDE10A inhibitor, CPL500036, in vivo. Methods: The potency of CPL500036 was demonstrated by microfluidic technology, and selectivity was investigated in a radioligand binding assay against 44 targets. Cardiotoxicity in vitro was evaluated in human ether-a-go-go related gene (hERG)-potassium channel-overexpressing cells by the patch-clamp method and by assessing key parameters in 3D cardiac spheroids. Cytotoxicity was determined in H1299, HepG2 and SH-SY5Y cell lines. The Ames test was used for genotoxicity analyses. During in vivo studies, CPL500036 was administered by oral gavage. CPL500036 exposure were determined by liquid chromatography-tandem mass spectrometry and plasma protein binding was assessed. The bar test was employed to assess catalepsy. Prolactin and glucose levels in rat blood were measured by ELISAs and glucometers, respectively. Cardiovascular safety in vivo was investigated in dogs using a telemetry method. Results: CPL500036 inhibited PDE10A at an IC50 of 1 nM, and interacted only with the muscarinic M2 receptor as a negative allosteric modulator with an IC50 of 9.2 µM. Despite inhibiting hERG tail current at an IC25 of 3.2 μM, cardiovascular adverse effects were not observed in human cardiac 3D spheroids or in vivo. Cytotoxicity in vitro was observed only at > 60 μM and genotoxicity was not recorded during the Ames test. CPL500036 presented good bioavailability and penetration into the brain. CPL500036 elicited catalepsy at 0.6 mg/kg, but hyperprolactinemia or hyperglycemic effects were not observed in doses up to 3 mg/kg. Conclusion: CPL500036 is a potent, selective and orally bioavailable PDE10A inhibitor with a good safety profile distinct from marketed antipsychotics. CPL500036 may be a compelling drug candidate.

Photothermal spectroscopy of CO2 in an intracavity mode-locked fiber laser configuration

A novel configuration of a photothermal gas sensor is demonstrated. Photothermal-induced gas refractive index (RI) modulation is probed by a simple, mode-locked (ML) ring cavity fiber laser, operating in the 1.55 µm wavelength region. The measured gas sample is placed in an open-path section of the ML laser and the RI variations directly translate to its optical path-length change, which is easily detectable as pulse repetition frequency deviations. Wavelength modulation spectroscopy (WMS) technique was used along with a custom-built FM demodulator simplifying the signal retrieval and acquisition. Normalized noise equivalent coefficient calculated for the sensor was 1 x 10^-5 cm^-1 W Hz^-1/2.

Hollow core fiber-assisted absorption spectroscopy of methane at 3.4 µm

A laser-based spectrometer exploiting a novel Kagome-type hollow core photonic crystal fiber, which serves as a gas cell is demonstrated. Low attenuation of this silica-based fiber in the 3.4 µm wavelength region enables accessing strong, fundamental transitions of methane, which was used as a target analyte in the presented experiment. With an all-fiber differential frequency generation source combined with wavelength modulation spectroscopy technique detection limit at single parts-per-million by volume level was obtained. These results show potential for developing compact and sensitive Kagome-fiber-based mid-infrared laser spectrometers.

Heterodyne interferometric signal retrieval in photoacoustic spectroscopy

A new heterodyne interferometric method for optical signal detection in photoacoustic or photothermal spectroscopy is demonstrated and characterized. It relies on using one laser beam for the photoacoustic excitation of the gas sample that creates refractive index changes along the beam path, while another laser beam is used to measure these changes. A heterodyne-based detection of path-length changes is presented that does not require the interferometer to be balanced or stabilized, which significantly simplifies the optical design. We discuss advantages of this new approach to photoacoustic signal detection and the new sensing arrangements that it enables. An open-path photoacoustic spectroscopy of carbon dioxide at 2003 nm and a novel sensing configuration that enables three-dimensional spatial gas distribution measurement are experimentally demonstrated.

Compact all-fiber figure-9 dissipative soliton resonance mode-locked double-clad Er:Yb laser

The first demonstration of a compact all-fiber figure-9 double-clad erbium-ytterbium laser working in the dissipative soliton resonance (DSR) regime is presented. Mode-locking was achieved using a nonlinear amplifying loop (NALM) resonator configuration. The laser was assembled with an additional 475 m long spool of SMF28 fiber in the NALM loop in order to obtain large net-anomalous cavity dispersion (-10.4  ps²), and therefore ensure that DSR would be the dominant mode-locking mechanism. At maximum pump power (4.78 W) the laser generated rectangular-shaped pulses with 455 ns duration and an average power of 950 mW, which at a repetition frequency of 412 kHz corresponds to a record energy of 2.3 μJ per pulse.

Dissipative soliton resonance mode-locked double clad Er:Yb laser at different values of anomalous dispersion

Emission of an all-fiber, Dissipative Soliton Resonance (DSR) mode-locked, Double-Clad (DC), Erbium-Ytterbium (Er:Yb) laser configuration is investigated under several different values of large anomalous dispersion. The laser was mode-locked by means of Nonlinear Amplifying Loop Mirror (NALM) in a Figure-8 (F8) resonator configuration. The boundaries of anomalous dispersion in which the laser operated in purely DSR regime was experimentally verified by changing the length of passive SMF28 fiber spliced into the NALM. The influence of 6 different values of dispersion (-1.061 ps² to -10.7 ps²) on the pulse properties is presented and discussed.

Amplification of noise-like pulses generated from a graphene-based Tm-doped all-fiber laser

We report on the generation of noise-like pulse (NLP) trains in a Tm-doped fiber laser mode-locked by multilayer graphene saturable absorber. The spectral bandwidth obtained directly from the oscillator exceeds 60 nm, centered at 1950 nm, with 23.5 MHz repetition rate. The pulses were also amplified in a fully fiberized amplifier based on a double-cladding Tm-doped fiber. The system was capable of delivering 1.21 W of average power, which corresponds to 51.5 nJ energy stored in the noise-like bundle. We believe that the presented source might serve as a pump for supercontinuum generation in highly nonlinear fibers.

All-fiber Ho-doped mode-locked oscillator based on a graphene saturable absorber

In this Letter, we demonstrate a graphene mode-locked, all-fiber Ho-doped fiber laser generating 1.3 nJ energy pulses directly from the oscillator. The graphene used as a saturable absorber was obtained via chemical vapor deposition on copper substrate and immersed in a poly(methyl methacrylate) support. The laser generated ultrashort soliton pulses at 2080 nm with bandwidth up to 6.1 nm. The influence of the output coupling ratio and the SA modulation depth on the mode-locking performance was also investigated.

Spectral coherence in all-normal dispersion supercontinuum in presence of Raman scattering and direct seeding from sub-picosecond pump

Intensity stability and wavelength correlations of near-infrared supercontinuum generation are studied in all-normal flattened dispersion, all-solid soft glass photonic crystal fiber. We use dispersive Fourier transformation method to measure shot-to-shot resolved spectra under pumping from a sub-picosecond, fiber-based chirped pulse amplification (CPA) system. For the first time to our knowledge, we demonstrate how unconverted radiation from pump, propagating in the photonic cladding of the fiber, improves the measured degree of coherence in the spectrum and influences its wavelength correlation by seeding of multiple four-wave-mixing / Raman scattering components. The presented results suggest a convenient and simple way of stabilizing of shot-to-shot coherence in sub-picosecond fiber laser pumped, normal-dispersion supercontinuum sources by direct, pump-related seeding.

Chirped laser dispersion spectroscopy with differential frequency generation source

A feasibility study of open-path methane detection at 3.4 μm using chirped laser dispersion spectroscopy (CLaDS) based on nonlinear differential frequency generation (DFG) laser source is performed. Application of a DFG source based on telecom laser sources and modulators allows mid-infrared CLaDS system to be optimized for measurements of gases at atmospheric conditions for which modulation in the GHz range is required. Excellent agreement between observed CLaDS signals and spectroscopic models has been observed.

Wavelength tunability and pulse duration control in frequency shifted feedback Er-doped fiber lasers

This paper presents the experimental studies on the all-fiber frequency shifted feedback erbium laser. Impact of the gain section profile on laser operation is shown. Two methods of wavelength tuning are presented. We obtained 8.3 and 10 nm tuning range in electrical and manual tuning respectively. Pulse duration can be also controlled and changed from 2 to 5 ps. The shortest pulses duration we have obtained was 1.7 ps.

Endoluminal phototherapy for prevention of restenosis: preliminary results at 6-month follow-up

OBJECTIVE

The objective of this observational study was to investigate safety and efficacy of laser phototherapy (LPh) in prevention of restenosis after percutaneous coronary intervention (PCI).

BACKGROUND DATA

Laser irradiation is known to cause a limitation of the local inflammatory cascade and a stimulation of proliferation of specific cells. Based on the results of previous experiments proving the beneficial effects of laser light on the activity of vascular and inflammatory cells, we attempted to use these properties to prevent restenosis.

METHODS

Laser phototherapy was performed in 41 patients after stent implantation or balloon angioplasty. Illumination power of 100 mW and energy dose equal to 9 J/cm(2) was used. Patients were monitored for major adverse cardiac events (MACE) after 30 days and 6 months. At 6 months, angiography as a control was performed to assess the influence of LPh on restenosis rate.

RESULTS

Angiographic follow-up (n = 30) revealed restenosis in 9% and 25% of patients after stent implantation and balloon angioplasty, respectively. The MACE rate was 4.5% and 12.5% in stent and balloon-treated patients, respectively.

CONCLUSIONS

Laser phototherapy gives very promising results in restenosis prevention, especially after stent implantation. The treatment method is safe, with a low rate of MACE in follow-up.

Photostimulation of coronary arteries with low power laser radiation: preliminary results for a new method in invasive cardiology therapy

BACKGROUND

The main problem after percutaneous coronary intervention (PCI) is restenosis affecting the site where dilatation is performed. In order to minimize its occurrence, the method of intravascular laser photostimulation (LP) with low power irradiation has been developed. The new procedure is carried out during PCI.

MATERIAL/METHODS

A special setup was prepared for intravascular photostimulation with 808 nm wavelength laser diode and special diffuser, delivering the laser light into the coronary artery. The construction of the device makes it possible to irradiate the coronary artery in the place of previously performed of dilatation, in an satisfactory and programmable manner and with uniform intensity. We describe our own, unique LP procedure. Two pilot LP procedures carried out in our clinic are described here. The patients were diagnosed before treatment and followed up three and six months after the LP procedure with non invasive tests. After six months, a control angiography was also performed.

RESULTS

The procedures were well tolerated. In both cases the follow-up examinations showed no evidence of restenosis.

CONCLUSIONS

The new, innovative technique of intravascular low power laser photostimulation is a relatively inexpensive and easy to use treatment method. No negative side effects were observed after two procedures. The results obtained are very promising. Because the group of treated patients is still too small, the results cannot yet be subjected to statistical analysis.