Freestanding sample holder for ultrafast optical spectroscopy at low temperatures

Ultrafast optical spectroscopy techniques are often employed to gain information about samples that are liquid at room temperature and frozen at cryogenic temperatures. However, the measurements suffer from the presence of unwanted, non-resonant signals originating in the sample cell walls. Most of these artifacts can be avoided in the measurements performed at room temperature by using liquid jet systems, i.e., by removing the sample cell. However, these systems cannot be used in low temperature measurements, when the sample is frozen. Herein we describe a freestanding sample holder that allows low temperature ultrafast spectroscopy measurements free of artifacts caused by the sample cell.

Abstract P5-14-04: Preoperative single-fraction partial breast radiotherapy – Initial results from a novel phase I dose-escalation protocol with exploration of radiation response biomarkers

Purpose/Objectives(s): Women with biologically favorable early stage breast cancer are increasingly treated with accelerated partial breast techniques. However, many alternative techniques require costly specialized equipment not routinely available in most radiation oncology facilities. In addition, suboptimal cosmetic outcomes have been reported with the external beam technique, possibly related to large post-operative treatment volumes. To address these issues, we designed a phase I dose-escalation protocol to determine the maximally tolerated dose (MTD) of a single radiosurgery treatment delivered preoperatively to the intact tumor plus a small margin.

Materials/Methods: Women aged 55 or older with clinically node negative, ER and/or PR+, HER2-, T1 invasive carcinomas were enrolled (n = 26). Patients with low/intermediate grade in situ disease <2cm were also included (n = 6). Breast MRI was required for target volume delineation. An intensity-modulated treatment plan was designed to deliver 15, 18, or 21Gy in a single fraction. An additional breast MRI, including T1-weighted, T2-weighted, diffusion-weighted and dynamic-contrast enhanced imaging, was obtained prior to lumpectomy which took place within 10 days of radiation treatment. Acute toxicity was assessed 3-4 weeks after radiation and any grade 3/4 toxicity possibly, probably, or definitely related to treatment was considered dose limiting.

Tumor tissue was obtained from diagnostic and lumpectomy specimens. Immunohistochemistry (IHC) for Fas was performed on paraffin-embedded samples before and after radiation. A histoscore was created using the average membrane and cytoplasmic staining intensity multiplied by the percentage of positive cells.

Results: Thirty-two women were treated, 8 each at the 15, 18, and 21Gy dose levels with an additional expansion cohort at the final 21Gy dose level. The maximally tolerated dose was not reached. Three patients required post-operative conventional radiation due to high-risk tumor features (ex. larger primary, nodal involvement).

At a median follow-up of 6.8 months, primarily mild toxicities (grade 1-2 dermatitis, fibrosis, and pain) were noted. At 6 months (n = 20), all reported cosmetic outcomes are excellent or good. At 12 months (n = 10), 80% are excellent or good. Both patients with a fair/poor cosmetic outcome received radiosurgery plus post-operative conventional treatment; one experienced grade 3 breast atrophy. There have been no local or distant recurrences to date.

Post-treatment MRIs were obtained in 20/32 patients, with early indicators of decreased cell density and increased vascular permeability. Sixteen patients had evaluable paired IHC and six demonstrated significant Fas up-regulation after radiation. The mean combined post-treatment histoscore was about twice as high as the mean pre-treatment score.

Conclusion: Preoperative stereotactic radiotherapy to the intact breast tumor can be delivered with widely available clinical tools in a convenient single fraction, and provides a unique opportunity to study breast cancer radiation response. 21Gy did not yield dose-limiting toxicity and will be utilized for future studies.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-14-04.

Nociceptive and pro-inflammatory effects of dimethylallyl pyrophosphate via TRPV4 activation

BACKGROUND AND PURPOSE

Sensory neuronal and epidermal transient receptor potential ion channels (TRPs) serve an important role as pain sensor molecules. While many natural and synthetic ligands for sensory TRPs have been identified, little is known about the endogenous activator for TRPV4. Recently, we reported that endogenous metabolites produced by the mevalonate pathway regulate the activities of sensory neuronal TRPs. Here, we show that dimethylallyl pyrophosphate (DMAPP), a substance produced by the same pathway is an activator of TRPV4.

EXPERIMENTAL APPROACH

We examined the effects of DMAPP on sensory TRPs using Ca²⁺ imaging and whole-cell electrophysiology experiments with a heterologous expression system (HEK293T cells transfected with individual TRP channels), cultured sensory neurons and keratinocytes. We then evaluated nociceptive behavioural and inflammatory changes upon DMAPP administration in mice in vivo.

KEY RESULTS

In the HEK cell heterologous expression system, cultured sensory neurons and keratinocytes, µM concentrations of DMAPP activated TRPV4. Agonistic and antagonistic potencies of DMAPP for other sensory TRP channels were examined and activation of TRPV3 by camphor was found to be inhibited by DMAPP. In vivo assays, intraplantar injection of DMAPP acutely elicited nociceptive flinches that were prevented by pretreatment with TRPV4 blockers, indicating that DMAPP is a novel pain-producing molecule through TRPV4 activation. Further, DMAPP induced acute inflammation and noxious mechanical hypersensitivities in a TRPV4-dependent manner.

CONCLUSIONS AND IMPLICATIONS

Overall, we found a novel sensory TRP acting metabolite and suggest that its use may help to elucidate the physiological role of TRPV4 in nociception and associated inflammation.

Q-switched neodymium-doped Y3Al5O12-based silica fiber laser

We present pulsed laser operation in a Nd-doped, Y3Al5O12-based silica fiber. The fiber was fabricated using the rod-in-tube technique with a Nd:YAG crystal rod as the core material and a silica tube for the cladding material. A spectroscopy study revealed that the core region had become amorphous in the process of fiber drawing. Q-switched pulsed laser operation was realized at a wavelength of 1058 nm when the fiber was cladding pumped at a wavelength of 808 nm. The laser delivered 38 μJ of energy in 65 ns pulses. The extracted energy was limited due to the multimodal operation of the fiber. Laser slope efficiency in continuous wave operation reached 52%. The spectroscopic properties of the fabricated fiber are discussed and compared to a Nd:YAG crystal and a Nd:Al-doped silica fiber.

SU-E-T-296: Optimization of the Energy Selection System with Varying Magnetic Field for Laser-Accelerated Proton Beams

PURPOSE

Laser-based accelerated proton beams are unsuitable for clinical use because of their broad energy spectra. For this reason, it is essential to employ an energy selection system (ESS). The purpose of this study is to determine optimum parameters of the ESS which uses a varying magnetic field to generate Bragg-peak.

METHODS

We simulated an accelerated proton beams using radiation pressure acceleration mechanism with carbon-proton mixture target. The density ratio (n = 6) between the protons and the carbon ions is one of optimization parameters in determining the accelerating mechanisms. The ESS was implemented by the Geant4 Monte Carlo toolkit. In order to optimize the hole size and position of the energy selection collimator, and magnetic field at ESS, these parameters were simulated for acquiring energy and dose distributions by changing each values.

RESULTS

The proton energy distributions had a poly-energetic distribution after passing through the ESS. As the magnetic field was increased, the mean energy of the proton beams also was increased. Also as the hole size was increased, the energy bandwidth of proton passed through the ESS was increased. The hole size and position of the energy selection collimator were effectively optimized to 2 cm and 5 cm from the z-axis, respectively.

CONCLUSIONS

We simulated laser-accelerated proton beams using ESS for generation of Bragg-peak. Our results suggest that the ESS with magnetic field variation can effectively generate a Bragg-peak suitable for use in proton radiation therapy. Our ESS can be applied to pencil beam scanning proton therapy.

17(R)-resolvin D1 specifically inhibits transient receptor potential ion channel vanilloid 3 leading to peripheral antinociception

BACKGROUND AND PURPOSE

Transient receptor potential ion channel vanilloid 3 (TRPV3) is expressed in skin keratinocytes and plays an important role in thermal and chemical nociceptions in the periphery. The presence of TRPV3 inhibitors would improve our understanding of TRPV3 function and help to develop receptor-specific analgesics. However, little is known about physiological substances that specifically inhibit TRPV3 activity. Here, we investigated whether 17(R)-resolvin D1 (17R-RvD1), a naturally occurring pro-resolving lipid specifically affects TRPV3 activity.

EXPERIMENTAL APPROACH

We examined the effect of 17R-RvD1 on sensory TRP channels using Ca(2+) imaging and whole cell electrophysiology experiments in a HEK cell heterologous expression system, cultured sensory neurons and keratinocytes. We also examined changes in sensory TRP agonist-specific acute licking/flicking or flinching behaviours and mechanical and thermal pain behaviours using Hargreaves, Randall-Selitto and von Frey assay systems in the absence and presence of inflammation.

KEY RESULTS

We showed that 17R-RvD1 specifically suppresses TRPV3-mediated activity at nanomolar and micromolar concentrations. The voltage-dependence of TRPV3 activation by camphor was shifted rightwards by 17R-RvD1, which indicates its inhibitory mechanism is as a result of a shift in voltage-dependence. Consistently, TRPV3-specific acute pain behaviours were attenuated by locally injected 17R-RvD1. Moreover, the administration of 17R-RvD1 significantly reversed the thermal hypersensitivity that occurs during an inflammatory response. Knockdown of epidermal TRPV3 blunted these antinociceptive effects of 17R-RvD1.

CONCLUSIONS AND IMPLICATIONS

17R-RvD1 is a novel natural inhibitory substance specific for TRPV3. The results of our behavioural studies suggest that 17R-RvD1 has acute analgesic potential via TRPV3-specific mechanisms.

Antimicrobial traits of tea- and cranberry-derived polyphenols against Streptococcus mutans

There are over 750 species of bacteria that inhabit the human oral cavity, but only a small fraction of those are attributed to causing plaque-related diseases such as caries. Streptococcus mutans is accepted as the main cariogenic agent and there is substantial knowledge regarding the specific virulence factors that render the organism a pathogen. There has been rising interest in alternative, target-specific treatment options as opposed to nonspecific mechanical plaque removal or application of broad-spectrum antibacterials that are currently in use. The impact of diet on oral health is undeniable, and this is directly observable in populations that consume high quantities of polyphenol-rich foods or beverages. Such populations have low caries incidence and better overall oral health. Camellia sinensis, the plant from which various forms of tea are derived, and Vaccinium macrocarpon (American cranberry fruit) have received notable attention both for their prevalence in the human diet as well as for their unique composition of polyphenols. The biologically active constituents of these plants have demonstrated potent enzyme-inhibitory properties without being bactericidal, a key quality that is important in developing therapies that will not cause microorganisms to develop resistance. The aim of this review is to consider studies that have investigated the feasibility of tea, cranberry, and other select plant derivatives as a potential basis for alternative therapeutic agents against Streptococcus mutans and to evaluate their current and future clinical relevance.

Resolvin D1 attenuates activation of sensory transient receptor potential channels leading to multiple anti-nociception

BACKGROUND AND PURPOSE

Temperature-sensitive transient receptor potential ion channels (thermoTRPs) expressed in primary sensory neurons and skin keratinocytes play a crucial role as peripheral pain detectors. Many natural and synthetic ligands have been found to act on thermoTRPs, but little is known about endogenous compounds that inhibit these TRPs. Here, we asked whether resolvin D1 (RvD1), a naturally occurring anti-inflammatory and pro-resolving lipid molecule is able to affect the TRP channel activation.

EXPERIMENTAL APPROACH

We examined the effect of RvD1 on the six thermoTRPs using Ca(2+) imaging and whole cell electrophysiology experiments using the HEK cell heterologous expression system, cultured sensory neurons and HaCaT keratinocytes. We also checked changes in agonist-specific acute licking/flicking or flinching behaviours and TRP-related mechanical and thermal pain behaviours using Hargreaves, Randall-Selitto and von Frey assay systems with or without inflammation.

KEY RESULTS

RvD1 inhibited the activities of TRPA1, TRPV3 and TRPV4 at nanomolar and micromolar levels. Consistent attenuations in agonist-specific acute pain behaviours by immediate peripheral administration with RvD1 were also observed. Furthermore, local pretreatment with RvD1 significantly reversed mechanical and thermal hypersensitivity in inflamed tissues.

CONCLUSIONS AND IMPLICATIONS

RvD1 was a novel endogenous inhibitor for several sensory TRPs. The results of our behavioural studies suggest that RvD1 has an analgesic potential via these TRP-related mechanisms.

Laser modulation of heat and capsaicin receptor TRPV1 leads to thermal antinociception

Er,Cr:YSGG lasers are used clinically in dentistry. The advantages of laser therapy include minimal thermal damage and the alleviation of pain. This study examined whether the Er,Cr:YSGG laser has in vivo and in vitro antinociceptive effects in itself. In capsaicin-evoked acute licking/shaking tests and Hargreaves tests, laser irradiation with an aerated water spray suppressed nociceptive behavior in mice. Laser irradiation attenuated TRPV1 activation by capsaicin in Ca(2+) imaging experiments with TRPV1-overexpressing cells and cultured trigeminal neurons. Therefore, the laser-induced behavioral changes are probably due to the loss of TRPV1 activity. TRPV4 activity was also attenuated, but limited mechanical antinociception by the laser was observed. The laser failed to alter the other receptor functions, which indicates that the antinociceptive effect of the laser is dependent on TRPV1. These results suggest that the Er,Cr:YSGG laser has analgesic effects via TRPV1 inhibition. Such mechanistic approaches may help define the laser-sensitive pain modality and increase its beneficial uses.

Performance comparison of Zr-based and Bi-based erbium-doped fiber amplifiers

In this Letter, we present a comprehensive comparison of the performance of a zirconia-based erbium-doped fiber amplifier (Zr-EDFA) and a bismuth-based erbium-doped fiber amplifier (Bi-EDFA). The experimental results reveal that a Zr-EDFA can achieve comparable performance to the conventional Bi-EDFA for C-band and L-band operations. With a combination of both Zr and Al, we could achieve a high erbium-doping concentration of about 2800 ppm (parts per million) in the glass host without any phase separations of rare earths. The Zr-based erbium-doped fiber (Zr-EDF) was fabricated using in a ternary glass host, zirconia-yttria-aluminum codoped silica fiber through a solution-doping technique along with modified chemical vapor deposition. At a high input signal of 0 dBm, a flat gain at average value of 13 dB is obtained with a gain variation of less than 2 dB within the wavelength region of 1530-1575 nm and using 2 m of Zr-EDF and 120 mW pump power. The noise figures are less than 9.2 at this wavelength region. It was found that a Zr-EDFA can achieve even better flat-gain value and bandwidth as well as lower noise figure than the conventional Bi-EDFA.