SU-E-T-06: A Mathematical Explanation to Tumor's Response to Perfusion and Hypoxic Fraction after Radiation

PURPOSE

To develop a dynamic model that explains oxygen dynamics between the microvascular perfusion and the hypoxic cell population inside a tumor.

METHODS

Bussink et al (Radiat Res 153(4), p.398 (2000)) observed fast oxygen dynamics, faster than cell-death. Based on a simplified three-compartment-model: the microvasculature, well-oxygenated, and hypoxic tumor cell populations. We applied a first-order differential model for the tumor's transient response as a function of oxygen content within the blood vessels. The sink terms in our model for each compartment are fast changing parameters because radiation rapidly changes the oxygen consumption of the tumor cell in a time scale which is much faster than the population changes of the tumor. Transportation balance condition is also applied for each compartment.

RESULTS

Our simulation results can explain the experimental data in Bussink et al's (Radiat Res 153(4), p.398 (2000)) paper. We provide an explanation for the relative complex behavior of the microvascular perfusion after radiation that emphasizes the role of dynamic metabolic changes in addition to population changes.

CONCLUSIONS

A newly developed dynamic model leads our understanding to the interrelationship between microvascular oxygen content within the blood vessels and the hypoxia state of the tumor to a deeper level, which has the potential to provide the theoretical foundation for the patient' specific adaptive radiotherapy.

SU-E-J-197: A Novel Optical Interstitial Fiber Spectroscopic System for Real-Time Tissue Micro-Vascular Hemodynamics Monitoring

PURPOSE

To demonstrate a novel interstitial optical fiber spectroscopic system, based on diffuse optical spectroscopies with spectral fitting, for the simultaneous monitoring of tumor blood volume and oxygen tension. The technique provides real-time, minimally-invasive and quantification of tissue micro-vascular hemodynamics.

METHODS

An optical fiber prototype probe characterizesthe optical transport in tissue between two large Numerical Aperture (NA) fibers of 200μm core diameter (BFH37-200, ThorLabs) spaced 3-mm apart. Two 21-Ga medical needles are used to protect fiber ends and to facilitate tissue penetration with minimum local blunt trauma in nude mice with xenografts. A 20W white light source (HL-2000-HP, Ocean Optics) is coupled to one fiber with SMA adapter. The other fiber is used to collect light, which is coupled into the spectrometer (QE65000 with Spectrasuite Operating software and OmniDriver, Ocean Optics). The wavelength response of the probe depends on the wavelength dependence of the light source, and of the light signal collection that includes considerable scatter, modeled with Monte-Carlo techniques (S. Jacques 2010 J. of Innov. Opt. Health Sci. 2 123-9). Measured spectra of tissue are normalized by a measured spectrum of a white standard, yielding the transmission spectrum. A head-and-neck xenograft on the flank of a live mouse is used for development.

RESULTS

The optical fiber probe delivers and collects light at an arbitrary depth in the tumor. By spectral fitting of the measured transmission spectrum, an analysis of blood volume and oxygen tension is obtained from the fitting parameters in real time.

CONCLUSIONS

A newly developed optical fiber spectroscopic system with an optical fiber probe takes spectroscopic techniques to a much deeper level in a tumor, which has potential applications for real-time monitoring hypoxic cell population dynamics for an eventual adaptive therapy metric of particular use in hypofractionated radiotherapy.

SU-E-J-196: In-Vivo Tumor Blood-Oxygen Content Measurement via Interstitial Optical Transmission Spectroscopy

PURPOSE

To demonstrate the application of in-vivo diffuse optical transmission spectroscopy in quantifying oxygen saturation in interstitial tissue, and to use this technique to examine reoxygenation dynamics in real-time as tumors responds to radiotherapy.

METHODS

Two 200 micron core fiber optics were threaded through two 21 gauge hypodermic needles: one coupled to an OceanOptics QE65000 spectrometer, and the other to an Ocean Optics HL-2000-HP 20W light source. These needles were fixed approximately 3 mm apart, and inserted into nude mice with human head- and-neck tumor xenografts. The oxygen saturation was then measured as a function of time after irradiation at intervals of 0.5, 1, 2, 6, 12, and 24, to measure the tumors' prompt oxygen saturation response to radiation.

RESULTS

Blood volume, deoxy and oxy-hemoglobin concentrations were measured through least-squares fitting of transmission spectra. Furthermore, various configurations of interstitial fiber optic probes were explored to optimize signal strength. Improvement of the optical coupling to the biological system and a concurrent increase in source intensity are the main two focuses for boosting signal strength.

CONCLUSIONS

This work has the potential to give an understanding of the time-scales of hypoxia and reoxygenation in vivo as tumors respond to radiation injury. This technique is of particular interest for hypofractionated therapies particularly treatments of only two or three treatments, where optimizing treatment timing can increase the tumorcidal effect of the remaining fractions.

Secular trends in the prevalence of general and abdominal obesity among Chinese adults, 1993-2009

The objective of this study is to examine the trends in body mass index (BMI), waist circumference (WC) and prevalence of overweight (BMI 25-27.49 kg m(-2) ), general obesity (BMI ≥ 27.5 kg m(-2) ) and abdominal obesity (WC ≥ 90 cm for men and ≥80 cm for women) among Chinese adults from 1993 to 2009. Data were obtained from the China Health and Nutrition Survey, which was conducted from 1993 to 2009 and included a total of 52,621 Chinese adults. During the period of 1993-2009, mean BMI values increased by 1.6 kg m(-2) among men and 0.8 kg m(-2) among women; mean WC values increased by 7.0 cm among men and 4.7 cm among women. The prevalence of overweight increased from 8.0 to 17.1% among men (P < 0.001) and from 10.7 to 14.4% among women (P < 0.001); the prevalence of general obesity increased from 2.9 to 11.4% among men (P < 0.001) and from 5.0 to 10.1% among women (P < 0.001); the prevalence of abdominal obesity increased from 8.5 to 27.8% among men (P < 0.001) and from 27.8 to 45.9% among women (P < 0.001). Similar significant trends were observed in nearly all age groups and regions for both men and women. The prevalence of overweight, general obesity and abdominal obesity among Chinese adults has increased greatly during the past 17 years.

Ginsenoside-Rd improves outcome of acute ischaemic stroke - a randomized, double-blind, placebo-controlled, multicenter trial

BACKGROUND AND PURPOSE

 Ginsenoside-Rd is a receptor-operated calcium channel antagonist and has shown promise as a neuroprotectant in our phase II study. As an extended work, we sought to confirm its efficacy and safety of Ginsenoside-Rd in patients with acute ischaemic stroke.

METHODS

We conducted a randomized, double-blind, placebo-controlled trial involving 390 patients with acute ischaemic stroke in a 3:1 ratio to receive a 14-day intravenous infusion of Ginsenoside-Rd or placebo within 72 h after the onset of stroke. Our primary end-point was the distribution of disability scores on the modified Rankin scale (mRs) at 90 days.

RESULTS

  The efficacy analysis was based on 386 patients (Ginsenoside-Rd group: 290; placebo group: 96). Ginsenoside-Rd significantly improved the overall distribution of scores on the mRs, as compared with the placebo (P = 0.02; odds ratios [OR], 1.74; 95% confidence interval [CI], 1.08-2.78). There were significant differences between the two groups when we categorized the scores into 0-1 vs. 2-5 (P = 0.01; OR, 2.32; 95% CI, 1.23-4.38; 66.8% vs. 53.1%). It also improved the National Institutes of Health Stroke Scale (NIHSS) at 15 days [P < 0.01; least squares mean (LSM), -0.77; 95% CI, -1.31 to -0.24]. Mortality and rates of adverse events were similar in the two groups.

CONCLUSIONS

  Ginsenoside-Rd improved the primary outcome of acute ischaemic stroke and had an acceptable adverse-event profile.

Psychometric properties of the Chinese version of Dermatology Life Quality Index (DLQI) in 851 Chinese patients with psoriasis

BACKGROUND

The Dermatology Life Quality Index (DLQI) is one of the most frequently used scales to evaluate the impact of skin disease on patients' quality of life (QoL). There has not been psychometric evaluation of the Chinese version of DLQI in Chinese patients with psoriasis.

OBJECTIVE

The objective of this study was to evaluate the psychometric properties of the Chinese version of DLQI.

METHODS

Patients with psoriasis (≥ 18 years old) visiting nine hospitals in various regions of China were enrolled in the study. The DLQI, Psoriasis Disability Index (PDI) and Health Survey Short Form (SF-36) were completed. Severity of psoriasis was assessed by the Psoriasis Area Severity Index (PASI). Reliability was estimated by internal consistency. Validity was assessed using known-groups comparison, convergent validity and construct validity.

RESULTS

In all, 851 patients were included in the study. The internal consistency reliability of the DLQI was high (Cronbach's alpha = 0.91). Known-groups comparison showed that the DLQI discriminated well among patients who differed in age, geographical region, duration of psoriasis and the PASI score. Evidence of convergent validity of the DLQI was proved by high correlations with the PDI and four subscales of SF-36 (role-physical, bodily pain, social functioning and role-emotional): r = 0.52-0.78. Construct validity was proved by the presence of one-factor structure that accounted for 55.9% of the variance and fitted well into the unidimensional model.

CONCLUSION

The Chinese version of DLQI is a reliable and valid measure to assess patient-reported impact of skin disease and could be used in QoL and health outcome studies on Chinese psoriasis patients.

Al2O3 and TiO2 atomic layer deposition on copper for water corrosion resistance

Al(2)O(3) and TiO(2) atomic layer deposition (ALD) were employed to develop an ultrathin barrier film on copper to prevent water corrosion. The strategy was to utilize Al(2)O(3) ALD as a pinhole-free barrier and to protect the Al(2)O(3) ALD using TiO(2) ALD. An initial set of experiments was performed at 177 °C to establish that Al(2)O(3) ALD could nucleate on copper and produce a high-quality Al(2)O(3) film. In situ quartz crystal microbalance (QCM) measurements verified that Al(2)O(3) ALD nucleated and grew efficiently on copper-plated quartz crystals at 177 °C using trimethylaluminum (TMA) and water as the reactants. An electroplating technique also established that the Al(2)O(3) ALD films had a low defect density. A second set of experiments was performed for ALD at 120 °C to study the ability of ALD films to prevent copper corrosion. These experiments revealed that an Al(2)O(3) ALD film alone was insufficient to prevent copper corrosion because of the dissolution of the Al(2)O(3) film in water. Subsequently, TiO(2) ALD was explored on copper at 120 °C using TiCl(4) and water as the reactants. The resulting TiO(2) films also did not prevent the water corrosion of copper. Fortunately, Al(2)O(3) films with a TiO(2) capping layer were much more resilient to dissolution in water and prevented the water corrosion of copper. Optical microscopy images revealed that TiO(2) capping layers as thin as 200 Å on Al(2)O(3) adhesion layers could prevent copper corrosion in water at 90 °C for ~80 days. In contrast, the copper corroded almost immediately in water at 90 °C for Al(2)O(3) and ZnO films by themselves on copper. Ellipsometer measurements revealed that Al(2)O(3) films with a thickness of ~200 Å and ZnO films with a thickness of ~250 Å dissolved in water at 90 °C in ~10 days. In contrast, the ellipsometer measurements confirmed that the TiO(2) capping layers with thicknesses of ~200 Å on the Al(2)O(3) adhesion layers protected the copper for ~80 days in water at 90 °C. The TiO(2) ALD coatings were also hydrophilic and facilitated H(2)O wetting to copper wire mesh substrates.

Comparative proteomic analysis of grain development in two spring wheat varieties under drought stress

Two spring wheat varieties Ningchun 4 and Chinese Spring with good and poor resistance to abiotic stress, respectively, were used to investigate proteomic changes in the developing grains under drought stress by a comparative proteomics approach. A total of 152 protein spots showed at least twofold differences in abundance on two-dimensional electrophoresis (2-DE) maps, of which 28 and 68 protein spots were identified by MALDI-TOF and MALDI-TOF/TOF mass spectrometry, respectively. Of the 96 identified protein spots, six different expression patterns were found and they were involved in stress/defense/detoxification, carbohydrate metabolism, photosynthesis, nitrogen metabolism, storage proteins and some other important functions. Comparative proteomic analysis revealed that under the drought conditions the decreased degree of ascorbate peroxidases was more significant in Chinese Spring than in Ningchun 4 during grain development whereas translationally controlled tumor protein, which was significantly upregulated at 14 DAF, was present in Ningchun 4 and absent in Chinese Spring. The Rubisco large subunit displayed an upregulated expression pattern in Ningchun 4. In addition, two drought-tolerant proteins, triosephosphate isomerase and oxygen-evolving complex showed B and F type expression patterns in Chinese Spring, but D and B types in Ningchun 4, respectively. These differentially expressed proteins might be responsible for the stronger drought resistance of Ningchun 4 compared to Chinese Spring.