Maximal Decline Research Articles

Oxygen is a critical parameter for chondrogenic differentiation of human umbilical cord blood mesenchymal stem cell in 3D-cultures

Oxygen is a critical parameter for chondrogenic differentiation of human umbilical cord blood mesenchymal stem cell in 3D-cultures

Using a non-invasive assessment of lung injury in a murine model of acute lung injury

Arterial oxygen saturation has not been assessed sequentially in conscious mice as a direct consequence of an in vivo murine model of acute lung injury. Here, we report daily changes...

Prediction of Virological Response and Assessment of Resistance Emergence to the HIV-1 Attachment Inhibitor BMS-626529 During 8-Day Monotherapy With Its Prodrug BMS-663068

BMS-663068 is the phosphonooxymethyl prodrug of BMS-626529, a small-molecule attachment inhibitor that targets the HIV-1 envelope glycoprotein gp120 preventing it from binding to CD4 T cells. In vitro investigations have demonstrated considerable variation in susceptibility of different HIV-1 isolates to BMS-626529. BMS-663068 monotherapy in HIV-1-infected subjects produced a mean maximum change from baseline of -1.64 log10 copies per milliliter, but the response was variable. In this analysis, baseline and day 8 samples were analyzed for susceptibility to BMS-626529 and the presence of known HIV-1 attachment inhibitor resistance mutations. In addition, predictors of virological response (maximal HIV-1 RNA decline ≥1 log10 copies per milliliter) and resistance selection were investigated. The only factor associated with reduced virological response was low baseline susceptibility to BMS-626529. There was no apparent relationship between virological response and baseline treatment experience, coreceptor tropism, plasma HIV-1 RNA level, or CD4 T-cell count. Examination of all positions with known BMS-626529 resistance mutations based on in vitro selection studies showed that gp120 M426L was the primary substitution most clearly associated with nonresponse to BMS-663068. There was minimal change in susceptibility to BMS-626529 over the course of the study and no clear evidence of emergence of a known HIV-1 attachment inhibitor resistance mutation in the majority of subjects as measured by standard population-based phenotypic and genotypic approaches. Nonresponse to BMS-663068 was associated with low baseline susceptibility to BMS-626529 and the presence of M426L. In this short-term trial, there was minimal evidence of selection for BMS-626529 high-level resistance over 8 days of monotherapy with BMS-663068 by population-based approaches.

Sulforaphane treatment in men with recurrent prostate cancer.

5017 Background: Diets high in cruciferous vegetables are strongly associated with lower prostate cancer risk. Sulforaphane is a constituent of these foods postulated to harbor the anti-neoplastic activity based on pre-clinical evidence in multiple tumor models. Our own work demonstrates that sulforaphane inhibits HDAC function and suppresses AR signaling in prostate cancer cells (Gibbs, et al PNAS 2009). However, the anti-tumor efficacy and safety of sulforaphane in men with prostate cancer was unknown. Methods: In this single arm study, we treated patients with biochemical (PSA)-recurrence of prostate cancer with 200 µmol of sulforaphane extracts for up to 20 weeks. The primary endpoint was PSA response rate (>50% decline in PSA). Other efficacy endpoints included: maximal PSA decline and percent change in PSA from baseline to end of study. We also analyzed PSA doubling time changes using a mixed effects model. Genotyping for GSTM1 that contributes to sulforaphane metabolism, sulforaphane pharmacokinetics (PK), and pharmacodynamic (PD) measurements of HDAC inhibition in mononuclear cells (MCs) were also performed. Results: Twenty patients were enrolled, and 16/20 (80%) completed the pre-planned 20 weeks of treatment. One patient experienced a PSA decline >50%. Thirty-five percent of patients had lesser PSA declines (3% to 20%), and 15% of patients had a final PSA lower than baseline. There was a significant reduction in PSA doubling time (6 months pre-study vs. 9.4 months on-study, p=.013). Of note, testosterone levels remained non-castrate in all subjects. PK analysis demonstrated that GSTM1 null genotype correlated with longer sulforaphane T1/2 (half-life) (2.6 hours for GSTM1 null vs. 2.1 hours for GSTM1 intact, p=0.04). Sulforaphane treatment also increased histone acetylation in PD assays in MCs. Finally, no grade three adverse events were seen, and only one patient discontinued study treatment for toxicity (grade one GI discomfort). Conclusions: Treatment with 200 µmol per day of sulforaphane is feasible, safe, and inhibits HDAC function. This combined with the preliminary observation of PSA modulation, which may indicate biologic activity, provides the basis for dose escalation studies of sulforaphane in men with prostate cancer. Clinical trial information: NCT01228084.

Significant Decrease in the Incidence of Genital Warts in Young Danish Women After Implementation of a National Human Papillomavirus Vaccination Program

Approximately 90% of genital warts (GWs) are caused by human papillomavirus (HPV) types 6 and 11. Denmark has provided the quadrivalent HPV vaccine to all 12-year-old girls since 2009 and catch-up vaccination to girls up to 15 years since 2008, with up to 80% to 85% vaccine coverage. We determined the incidence of GWs in Denmark since 1996, focusing on the period after licensing of HPV vaccination (October 2006). From the Danish National Patient Register, we identified all hospitalizations and outpatient consultations for GWs between January 1995 and July 2011. Poisson regression was used to estimate average annual percentage changes. The overall incidence of GWs in women increased significantly until 2007, followed by an average yearly decline of 3.1% (95% confidence interval [CI], -5.5 to -0.7). In men, the incidence increased by 6.2% per year from 2004 (95% CI, 4.6-7.8). Stratifying on age, a significant decline was seen only for young women, particularly those aged 16 to 17 years, in whom GWs were virtually eliminated (average annual percentage change, -45.3%; 95% CI, -55.8 to -33.3). The incidences of genital Chlamydia, syphilis, and gonorrhea were stable or increased during the study period. The incidence of GWs decreased substantially among women with high HPV vaccine coverage, pointing to the effect of the national HPV vaccination program.

Sequential effects of cadmium on plant growth, biochemical and cyto-physiological aspects, antioxidant activity, and molecular screening of protein by SDS-PAGE in Trigonella

The present study was designed to investigate the effects of cadmium (Cd) on biochemical, physiological and cytological parameters of Trigonella treated with six different concentrations 0, 25, 50, 75, 100, or 125 ppm of metal. Germination%, root-shoot length, pigment, proline, and protein content showed a continuous decrease with increasing Cd concentrations and the maximal decline was observed at the higher concentration while the frequency of chromosomal aberrations rose with increasing metal concentration. Malondialdehyde content was found to be two-fold higher than control at 125 ppm Cd. On other hand the activities of superoxide dismutase (SOD) and glutathione peroxidase (GDP) rose more than two-fold and the peaked at 75 ppm of Cd. Thus, SOD and GDP were more sensitive to Cd than other involved in reactive oxygen species quenching mechanism. Additionally protein profiling by SDS-PAGE revealed that there was 89% polymorphism and considerable inter-specific variation in the analyzed accessions. Variation in the major bands was present in case of S1 and S5, whereas the accessions showed differences for the minor bands. Three new bands such as 30, 33, and 34 were present only in case of S5 which might be related to improvement of traits studied in Trigonella.

Abstract 2696: Modulation of intracrine androgen signaling in bone metastatic castrate resistant prostate cancer (bmCRPC) by MDV3100

Abstract Background Androgen signaling is a central driver in CRPC. We performed a study to determine the effect of the antiandrogen MDV 3100 on bone marrow infiltrating CRPC. Methods From February 2010 to June 2011, we performed an open-label, observational study of 60 bmCRPC patients (pts), who underwent transilial bone marrow biopsy (BMB) at baseline and 8 weeks of treatment. Pts received MDV3100 160mg orally once daily. The primary objective was to evaluate androgen signaling in bone marrow infiltrating cancer and testosterone in blood (BT) and bone marrow (BMT) and correlate findings with clinical observations. Androgen receptor (AR), CYP17 and phospho Src (pSrc) expression were assessed by immunohistochemistry, and BT and BMT by liquid chromatography mass spectrometry. Findings Maximal PSA decline of Δ50% occurred in 29 (48%) of 60 pts, and α90% in 13 (22%). Tumor involvement in BMB was detected in 28 (47%) pretreatment BMBs. Paired tumor infiltrated BMBs were found in 23 (38%) pts. Pretreatment androgen signaling and pSrc tumor expression is shown in Table 1. Pretreatment intense nuclear AR expression combined with α10% CYP17 tumor expression or increased BMT correlate with Δ50% PSA decline (p value 0.02). AR subcellular localization shift from dominant nuclear to cytoplasmic correlate with Δ50% PSA decline (p value 0.05). Increased pretreatment p-Src expression is associated with lack of PSA decline (p value 0.002). Increase in BMT and BT is observed after 8 weeks of MDV3100. (Mean Pretreatment BMT 0.03 ng/ml, Wk8 BMT 0.04 in 33pts, p value 0.0009) (Pretreatment BT 0.05, wk8 BT 0.066 in 37 pts, p value 0.0001) Interpretation Pretreatment expression profile is consistent with persistent androgen signaling in bmCRPC. MDV3100 induces ‘pharmacodynamic’ changes in Androgen Signaling. AR changes likely account for the reported therapeutic effect of MDV3100. These data prompt exploratory combinations of MDV3100 with Androgen Biosynthesis Inhibitors and src inhibitors. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2696. doi:1538-7445.AM2012-2696

Abstract A2: A Study of the effects of MDV3100 in the tumor microenvironment of bone metastatic castrate resistant prostate cancer (bmCRPC)

Abstract Background: Androgen signaling remains a central driver in castrate-resistant prostate cancer. We performed a study to determine the effect of the antiandrogen MDV 3100 on bone marrow infiltrating CRPC. Methods: From February 2010 to June 2011, we performed an open-label, observational study of 60 bmCRPC patients (pts), who underwent transilial bone marrow biopsy (BMB) at baseline, 8 weeks and end of study. Pts received MDV3100 160mg orally once daily. The primary objective was to evaluate androgen signaling in bone marrow infiltrating cancer and testosterone in blood (BT) and bone marrow (BMT) and correlate findings with clinical observations. Androgen receptor (AR) c-terminus n-terminus, AR Variant 7 (ARV7), ERG, CYP17, phospho Src (pSrc), expression and mitotic index (Ki67 ) were assessed by immunohistochemistry, AR copy number by qPCR and BT and BMT by liquid chromatography mass spectrometry. Initial Findings: Maximal PSA decline of ≥50% occurred in 29 (48%) of 60 pts, and ≥90% in 13 (22%). Tumor involvement in BMB was detected in 28 (47%) pretreatment BMBs. Paired tumor infiltrated BMBs were found in 23 (38%) pts. Increased androgen receptor expression (n-terminal antibody used for IHC) was observed at pretreatment with heterogeneous CYP17 and pSrc extent of expression. Pretreatment intense nuclear AR expression combined with ≥10% CYP17 tumor expression or increased BMT correlate with ≥50% PSA decline (p value 0.02). AR subcellular localization shift from dominant nuclear to cytoplasmic and regression of bone marrow tumor infiltration correlate with ≥50% PSA decline (p value 0.05). Increased pretreatment p-Src expression is associated with lack of PSA decline (p value 0.002). Increase in BMT and BT is observed after 8 weeks of MDV3100 (mean pretreatment BMT 0.026 ng/ml, Wk8 BMT 0.04 in 33pts, p value 0.0001) (pretreatment BT 0.041, wk8 BT 0.066 in 37 pts, p value <0.0001). Interpretation: Pretreatment expression profile is consistent with persistent androgen signaling in bmCRPC. MDV3100 induces pharmacodynamic changes in androgen signaling. AR changes likely account for the reported therapeutic effect of MDV3100. These data prompt exploratory combinations of MDV3100 with androgen biosynthesis inhibitors and src inhibitors. Citation Format: Eleni Efstathiou, Patricia Troncoso, James Mohler, Christopher J. Logothetis, Mark Titus, Dimitra Tsavachidou, Sijin Wen, Anh Hoang, Robynne Ashe, Maria Karlou, Craig Berman. A study of the effects of MDV3100 in the tumor microenvironment of bone metastatic castrate-resistant prostate cancer (bmCRPC) [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr A2.

Pharmacokinetics, Pharmacodynamics, and Tolerability of a Generic Formulation of Exenatide: A Randomized, Open-Label, Single- and Multiple-Dose Study in Healthy Chinese Volunteers

A randomized, open-label, dose-escalating study was designed to assess the pharmacokinetics, pharmacodynamics and tolerability of single and multiple subcutaneous administrations of exenatide in 24 healthy Chinese volunteers. The effects of gender on the pharmacokinetics of exenatide were also evaluated. Subjects were randomized to receive a single and multiple subcutaneous doses of 5 or 10 μg of exenatide. Following the single dose subjects received exenatide twice daily on days 2-4 and once on day 5. Sequential blood samples were collected at regular intervals from 0 to 8 h after single administration. Concomitantly the serum glucose concentrations were measured in each sample. Tolerability was assessed using physical examination, vital signs, laboratory analysis, and by interview of subjects. Pharmacokinetic parameters for exenatide after subcutaneous administration of a single dose of 5-10 μg were as follows: Cmax=77.7 (13.9) and 136.1 (15.2) pg/mL; AUC0-t=184.2 (49.7) and 309.7 (52.3) pg·h/mL; AUC0-∞=225.8 (77.4) and 365.4 (68.8) pg·h/mL; tmax (median [range])=1.00 (0.75-1.50) and 1.00 (0.75-1.50) h; t1/2 (mean [range])=1.4 (0.7-3.2) and 1.8 (1.0-2.5) h, respectively. Because of its short t1/2, Css, min could not be detected in any plasma samples prior to daily dosing on days 3-5. Pharmacokinetic parameters for exenatide after administration of multiple doses of 5 or 10 μg were as follows: Cmax=81.2 (12.2) and 144.5 (13.3) pg/mL; AUC0-t=181.1 (39.4) and 275.6 (45.0) pg·h/mL; AUC0-∞=217.2 (44.8) and 313.3 (48.4) pg·h/mL; tmax=1.10 (0.75-1.25) and 1.00 (1.00-1.25) h; t1/2=1.6 (0.8-2.2) and 1.4 (0.9-2.7) h, respectively. Both doses of exenatide were associated with significant reductions in serum glucose concentrations (P<0.001) when compared to baseline levels. Mean percentage of maximal decline for serum glucose concentrations after single and multiple doses were 15.6% and 19.9% for 5 μg, respectively; as well as 26.3% and 28.7% for 10 μg, respectively. 12 of the 24 subjects reported a total of 75 adverse events. The rate increased with higher doses of exenatide: after 5 μg only one subject experienced at least 1 adverse event but following 10 μg 11 subjects were affected. 2 subjects receiving the higher dose of 10 μg exenatide dropped out because of adverse events (nausea and vomiting). The most common adverse events were of gastrointestinal origin (e. g. decreased appetite, nausea and vomiting) and of mild severity. In conclusion, in healthy Chinese subjects, AUC and Cmax increased in proportion to the dose, whereas t1/2 was independent of dose. The pharmacokinetic parameters after multiple dosing were consistent with those after single doses. No significant gender differences were noted for pharmacokinetic variables. Both exenatide doses were associated with significant reductions in serum glucose levels. Adverse events were mainly of gastrointestinal origin and their incidence was dose-dependent.

Effect of an Acute Consumption of a Moderate Amount of Ethanol on Plasma Endocannabinoid Levels in Humans

Animal experiments have shown that the endocannabinoid system (ECS) plays an important role in the regulation of ethanol intake. We investigated these effects in healthy volunteers who consumed a moderate amount of ethanol (red wine) and measured plasma levels of the endocannabinoids (ECs) anandamide (AEA) and 2-arachidonoylglycerol (2-AG) to test whether alcohol consumption influences the ECS in humans. Grape juice or plain non-sparkling water served as non-alcoholic control liquids. In total, 55 adults were enrolled in this study and assigned to one of three groups drinking either 250 ml of red wine (28.0 g of ethanol, <0.8 g of sugar and 187.5 kcal), grape juice (41.0 g of sugar, 187.5 kcal) or plain water within 10 min. Twenty minutes and 45 min thereafter, AEA, 2-AG, ethanol and glucose levels were determined from venous plasma samples. AEA, 2-AG and plasma glucose levels were significantly reduced after red wine consumption. AEA had its maximal decline at 20 min (from 0.23 ± 0.12 to 0.18 ± 0.07 ng/ml, P < 0.01), whereas the nadir of 2-AG was seen after 45 min and dropped from 6.68 ± 4.13 to 5.49 ± 3.22 ng/ml (P < 0.05). Grape juice highly affected blood glucose level after 20 min, with a return to baseline after 45 min. ECs remained almost unchanged by this intervention. Water intake had no significant effect on AEA (0.21 ± 0.08 at baseline and 0.19 ± 0.06 after 45 min) but resulted in a gradual reduction in 2-AG concentrations which became significant at 45 min when compared with baseline. The consumption of a moderate amount of red wine reduces plasma AEA and 2-AG concentrations, whereas the volume and caloric equivalent of the sugar containing, non-alcoholic liquid grape juice does not affect plasma ECs. Plain water has a differential effect on the ECS by reducing 2-AG concentrations without affecting AEA.

Effect of Dust Aerosol in Patients with Asthma

Objective. Sandstorms frequently cause adverse health effects especially in patients with asthma. The aim of our research was to explore the mechanism of sandstorm-induced asthmatic exacerbation by administering dust aerosol through an environmentally controlled exposure chamber. Methods. Four samples of soil (Ganganagar clay, Bikaner sand, Jaipur sand, and Ganganagar sand) were collected from three sandstorm-prone areas of Rajasthan, the desert state of India. Twenty patients with asthma, who had stable disease with a forced expiratory volume in first second (FEV1) more than 70% of predicted, volunteered to participate in this randomized single-blind placebo-controlled crossover study. The four samples of dust and placebo were administered randomly on 5 study days. FEV1 was measured for the next 60 minutes and the maximal decline in FEV1 (ΔFEV1) from baseline was measured. The samples of dust were also analyzed for particle size and adhesiveness. Results. The maximal decline in FEV1 was observed 15 minutes post-exposure with all dust samples. Mean ΔFEV1 was 0.69 ± 0.08 liters for Ganganagar clay, 0.52 ± 0.06 liters for Bikaner sand, 0.39 ± 0.07 liters for Jaipur sand, and 0.32 ± 0.04 liters for Ganganagar sand dust aerosol samples. Decline in FEV1 correlated with volume of dust particles with size <10 μm (PM10) and adhesiveness of the dust particles. Conclusion. Smaller-size sandstorm dust particles with higher adhesive properties have a greater potential of aggravating asthma.

Effects of Abiraterone Acetate on Androgen Signaling in Castrate-Resistant Prostate Cancer in Bone

Persistent androgen signaling is implicated in castrate-resistant prostate cancer (CRPC) progression. This study aimed to evaluate androgen signaling in bone marrow-infiltrating cancer and testosterone in blood and bone marrow and to correlate with clinical observations. This was an open-label, observational study of 57 patients with bone-metastatic CRPC who underwent transiliac bone marrow biopsy between October 2007 and March 2010. Patients received oral abiraterone acetate (1 g) once daily and prednisone (5 mg) twice daily. Androgen receptor (AR) and CYP17 expression were assessed by immunohistochemistry, testosterone concentration by mass spectrometry, AR copy number by polymerase chain reaction, and TMPRSS2-ERG status by fluorescent in situ hybridization in available tissues. Median overall survival was 555 days (95% CI, 440 to 965+ days). Maximal prostate-specific antigen decline ≥ 50% occurred in 28 (50%) of 56 patients. Homogeneous, intense nuclear expression of AR, combined with ≥ 10% CYP17 tumor expression, was correlated with longer time to treatment discontinuation (> 4 months) in 25 patients with tumor-infiltrated bone marrow samples. Pretreatment CYP17 tumor expression ≥ 10% was correlated with increased bone marrow aspirate testosterone. Blood and bone marrow aspirate testosterone concentrations declined to less than picograms-per-milliliter levels and remained suppressed at progression. The observed pretreatment androgen-signaling signature is consistent with persistent androgen signaling in CRPC bone metastases. This is the first evidence that abiraterone acetate achieves sustained suppression of testosterone in both blood and bone marrow aspirate to less than picograms-per-milliliter levels. Potential admixture of blood with bone marrow aspirate limits our ability to determine the origin of measured testosterone.

Mechanisms underlying muscle fatigue differ between multiple sclerosis patients and controls: A combined electrophysiological and neuroimaging study

Increased sense of fatigue is an important and conspicuous symptom in multiple sclerosis (MS). Muscle fatigue is associated with increased sense of fatigue in MS (Steens et al., 2011). The aim of this study was to investigate mechanisms that can explain muscle fatigue in MS patients and controls. We assessed changes in cortical activation (BOLD), voluntary activation (twitch interpolation) and muscle force during a sustained maximal voluntary contraction (MVC) in twenty MS patients and twenty healthy controls. In control participants, individual differences in force decline (mean 65% MVC, 8 SD) during the sustained maximal contraction could be accounted for by differences in maximal voluntary force (R(2): 0.49, p = 0.001); stronger participants presented a larger force decline. The small decline in voluntary activation (mean 7.8%, 11.8 SD) did not contribute significantly to the force decline. During the sustained contraction, the force decline was accompanied by an increase in cortical activation in the main motor areas. In MS patients, the differences in the decline in force (mean 67% MVC, 9 SD) were significantly associated (R(2): 0.51, p = 0.001) with a decline in voluntary activation (mean 20.1%, 20.6 SD) and not with maximal force or decline in rest twitch. The corresponding cortical activation in motor areas showed an increase in the first two intervals of the sustained contraction but declined during the last interval. Our data indicate that muscle fatigue during a sustained contraction in MS patients is associated with changes in the voluntary activation that are not sufficiently compensated by increased cortical activation. Control participants, however, show increased cortical activation to compensate for these fatigue-related changes in voluntary activation and the major cause of force decline is therefore to be found in the periphery (muscles).

Brain Tumor Therapy-Induced Changes in Normal-Appearing Brainstem Measured With Longitudinal Diffusion Tensor Imaging

To characterize therapy-induced changes in normal-appearing brainstems of childhood brain tumor patients by serial diffusion tensor imaging (DTI). We analyzed 109 DTI studies from 20 brain tumor patients, aged 4 to 23 years, with normal-appearing brainstems included in the treatment fields. Those with medulloblastomas, supratentorial primitive neuroectodermal tumors, and atypical teratoid rhabdoid tumors (n = 10) received postoperative craniospinal irradiation (23.4-39.6 Gy) and a cumulative dose of 55.8 Gy to the primary site, followed by four cycles of high-dose chemotherapy. Patients with high-grade gliomas (n = 10) received erlotinib during and after irradiation (54-59.4 Gy). Parametric maps of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were computed and spatially registered to three-dimensional radiation dose data. Volumes of interest included corticospinal tracts, medial lemnisci, and the pons. Serving as an age-related benchmark for comparison, 37 DTI studies from 20 healthy volunteers, aged 6 to 25 years, were included in the analysis. The median DTI follow-up time was 3.5 years (range, 1.6-5.0 years). The median mean dose to the pons was 56 Gy (range, 7-59 Gy). Three patterns were seen in longitudinal FA and apparent diffusion coefficient changes: (1) a stable or normal developing time trend, (2) initial deviation from normal with subsequent recovery, and (3) progressive deviation without evidence of complete recovery. The maximal decline in FA often occurred 1.5 to 3.5 years after the start of radiation therapy. A full recovery time trend could be observed within 4 years. Patients with incomplete recovery often had a larger decline in FA within the first year. Radiation dose alone did not predict long-term recovery patterns. Variations existed among individual patients after therapy in longitudinal evolution of brainstem white matter injury and recovery. Early response in brainstem anisotropy may serve as an indicator of the recovery time trend over 5 years after radiation therapy.

SU‐D‐BRC‐05: Characterizing Therapy‐Induced Brainstem Injury and Recovery with Serial Diffusion Tensor Imaging

Purpose: To characterize therapy‐induced changes in normal‐appearing brainstems of childhood brain tumor patients by serial diffusion tensor imaging (DTI). Methods: We analyzed sequential DTI of 20 brain tumor patients, aged 4–23 years, with normal‐appearing brainstems included in the radiation treatment fields. Prescribed tumor doses ranged from 54 to 59.4 Gy. Parametric maps of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were computed and registered to three‐dimensional radiation dose data. Volumes of interest included corticospinal tracts, medial lemnisci, and the pons. Serving as an age‐related benchmark for comparison, DTI studies from 20 healthy volunteers, aged 6–25 years, were included in the analysis. Results: The median DTI follow‐up was 3.5 years (range, 1.6–5.0 years). The median mean dose to the pons was 56 Gy (range, 7–59 Gy). Three distinctive patterns of temporal changes in FA and ADC were observed in the pons: (1) a stable or normal developing time trend similar to those observed in healthy children, (2) initial deviation from normal with subsequent recovery, (3) progressive deviation without evidence of complete recovery. In this group of patients without severe brainstem necrosis, maximal decline in FA often occurred 1.5 to 3.5 years after the start of radiation therapy. A full recovery time trend could be observed within 4 years. Patients with incomplete recovery often had a larger decline in FA within the first year. Radiation dose alone did not predict long‐term recovery patterns. Conclusions: Longitudinal DTI analysis revealed variation among individual patients in diffusion properties of brainstems reflecting therapy‐induced white matter injury and recovery. Early response in brainstem anisotropy may serve as an indicator of the recovery time trend over 5 years following radiation therapy. Attention should be given to patients with pronounced early changes since DTI suggested their recovery was slower and less complete than other patients.Acknowledgement: NIH grant HD049888.

Abstract LB-421: Characterization of castrate resistant prostate cancer treated with abiraterone acetate and prednisone

Abstract Background: Recent observations implicate persistent androgen signaling in metastatic castrate-resistant prostate cancer (mCRPC) progression. Inhibition of CYP 17 lyase with abiraterone acetate (AA) prolongs survival of patients (pts.) with mCRPC progressing after docetaxel (de Bono et al ESMO 2010). Despite initial benefit to AA, most pts. develop disease progression. The purpose of this study is to better understand resistance by characterizing mCRPC in bone marrow of pts. on AA. Methods: From October 2007 to March 2010, we performed an open-label, study of 57 pts. with metastatic CRPC, who underwent transilial bone marrow biopsy at baseline, 8 weeks and progression. Pts. received AA, 1 g once daily, and prednisone, 5 mg twice daily. The objective was to evaluate androgen signaling in bone marrow-infiltrating cancer and testosterone in blood and bone marrow and to correlate findings with clinical observations. Androgen receptor (AR) and CYP17 expression was assessed by immunohistochemistry, and testosterone concentration by electrospray tandem mass spectrometry. AR copy numbers ( Real-Time PCR) and TMPRSS2-ERG ( FISH) were assessed in available tissues. Findings: Median overall survival was 555 days (95% CI: 440-965+). Maximal PSA decline of ≥50% occurred in 28 (50%) of 56 pts., and ≥90% in 9 (16%). Homogeneous, intense nuclear AR expression in combination with ≥10% CYP17 tumor expression correlated with longer time to treatment discontinuation (&amp;gt;4 months) in 25 pts. with tumor-infiltrated bone marrow. Pretreatment CYP17 expression of ≥10% in the tumor correlated with increased bone marrow testosterone. Blood and bone marrow testosterone concentration declined to below picogram levels and remained suppressed at progression. AR copy number increased over time in pts. with benefit from treatment as opposed to early progressors (≤ 4 months) where no difference was observed. Over expression of nuclear AR by immunohistochemistry was observed in (9/11) cancers from pts. benefiting, whereas 4/6 cancers from pts. with early progression a significant reduction in nuclear AR was seen. CYP 17 expression was lost in repeat biopsy performed at progression in 6/11 cancers available for analysis from pts. with prolonged response. Interpretation: The pretreatment expression profile observed is consistent with persistent androgen signaling in CRPC bone metastases. This is the first evidence that AA achieves sustained suppression of testosterone in blood and bone marrow to below picogram levels suggesting that progression is testosterone independent. Increased expression of AR in the context of sustained depletion of bone marrow testosterone by AA favors the hypothesis that "native ligand independent AR signaling" is implicated in abiraterone resistance. Our observations provide rationale for a combinatorial androgen signaling inhibition strategy. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-421. doi:10.1158/1538-7445.AM2011-LB-421

Biochemically altered human erythrocytes as a carrier for targeted delivery of primaquine: an In Vitro study

The aim of this study was to investigate human erythrocytes as a carrier for targeted drug delivery of primaquine (PQ). The process of PQ loading in human erythrocytes, as well as the effect of PQ loading on the oxidative status of erythrocytes, was also studied. At PQ concentrations of 2, 4, 6, and 8 mg/mL and an incubation time of 2 h, the ratios of the concentrations of PQ entrapped in erythrocytes to that in the incubation medium were 0.515, 0.688, 0.697 and 0.788, respectively. The maximal decline of erythrocyte reduced glutathione content was observed at 8 mg/mL of PQ compared with native erythrocytes p < 0.001. In contrast, malondialdehyde and protein carbonyl were significantly increased in cells loaded with PQ (p < 0.001). Furthermore, osmotic fragility of PQ carrier erythrocytes was increased in comparison with unloaded cells. Electron microscopy revealed spherocyte formation with PQ carrier erythrocytes. PQ-loaded cells showed sustained drug release over a 48 h period. Erythrocytes were loaded with PQ successfully, but there were some biochemical as well as physiological changes that resulted from the effect of PQ on the oxidative status of drug-loaded erythrocytes. These changes may result in favorable targeting of PQ-loaded cells to reticulo-endothelial organs. The relative impact of these changes remains to be explored in ongoing animal studies.

Resistance exercise‐induced hormonal response under the influence of delayed onset muscle soreness in men and boys

It was hypothesized that exercise-induced muscle damage (EIMD)-related alterations in hormonal responses could be observed if a second exercise bout is performed soon after an identical unaccustomed bout leading to delayed onset muscle soreness (DOMS). Eight men (31 ± 7 years) and eight boys (14 ± 0 years) performed two exercise bouts (E1 and E2, with 48 h rest in between) consisting of three sets of bilateral knee extensions until exhaustion with 40% load. No differences between the groups or bouts were observed in the number of repetitions performed and maximal isometric force decline, or between groups in serum creatine kinase activity and DOMS. Decreased peak epinephrine (EPI) (-38%), growth hormone (GH) (-45%) and cortisol (COR) (-31%) concentrations were found in E2 in men (P<0.05). In men, the peak GH concentration was also lower in E2 and COR was higher in both bouts than in boys. No changes in norepinephrine and testosterone responses were found in either group. The results suggest that in men, the responses of EPI, GH and COR are attenuated when the second bout is performed under the influence of DOMS. In boys, the lack of this attenuation may not be explained by less severe EIMD.

Short-term resistance training with blood flow restriction enhances microvascular filtration capacity of human calf muscles

Resistance training increases muscle strength and endurance but may require high intensity and long duration to enhance capillarity. Vascular occlusion during low-load resistance training augments the strength and endurance gains compared with low-load resistance training alone, but in this study we investigated whether it also promotes microvascular filtration capacity, an index of capillarity. Nine healthy males performed short-term low-intensity resistance training of the calf muscles (four sets of 50 heel raises, three times a week for 4 weeks) under restricted (thigh cuff inflated to 150 mmHg on the non-dominant leg) or unrestricted (dominant leg without thigh cuff) blood flow conditions. Before and after resistance training, calf filtration capacity and resting blood flow were assessed by strain gauge plethysmography, and calf muscle strength and fatigue were assessed respectively by maximal voluntary contraction and force decline during electrically evoked ischaemic contractions in both legs. Calf filtration capacity increased by 26% in the restricted leg but did not increase significantly in the unrestricted leg. Calf muscle strength was 18% greater in the restricted leg but unchanged in the unrestricted leg. Calf muscle fatigue and resting blood flow did not change in either leg. Resistance training promoted microvascular filtration capacity, an effect that was somewhat enhanced by blood flow restriction, and could be due to increased capillarization.

Gemcitabine and nab-paclitaxel in patients with unresectable/borderline resectable pancreatic cancer.

e14675 Background: Targeting the tumor stroma has evolved as a promising therapeutic strategy. Secreted protein acidic rich in cysteine (SPARC) which binds albumin has been putatively linked to enhanced drug delivery of nab-paclitaxel (ABX) to pancreatic tumor stroma. A recent phase I/II study demonstrated a 44% response in patients with metastatic pancreatic cancer treated with gemcitabine (gem) and ABX (Von Hoff et al, ASCO 2009). Based on these encouraging results, a pilot investigation was conducted in patients with unresectable (UR)/borderline resectable (BR) disease. Methods: A retrospective review was done on UR/BR pancreatic ca patients treated at Mayo Clinic Arizona from 3/09-12/09. Patients received gemcitabine 1,000 mg/m2 and nab-paclitaxel 100-125 mg/m2 neoadjuvantly. Demographics, staging, RECIST response, CA19-9 response (defined as > 50% maximal decline), EORTC PET response, post-treatment resectabilty and treatment related toxicities were assessed. Results: 13 patients were treated with this combination (age: median 69, range 47-86 years; sex: male 6, female 7, ECOG: 0-10, 1-3; location: head 8, body 5, median baseline CA19-9: 397 u/mL). A median of 3 cycles of therapy was delivered (range: 3-6). 3/13 (23%) underwent surgical resection with curative intent. CA19-9 response was 13/13 (100%), RECIST response was: PR-9/13 (69%), SD-3/13 (23%) and PD-1/13 (8%). EORTC PET response was: PR-7/10 (70%), SD3/10 (30%). No patients encountered drug related grade 4 or higher toxicities. There were 2 cases of grade 3 neutropenia,1 case of grade 3 anemia and no cases of grade 3 or higher thrombocytopenia; 4 patients had grade 2 neuropathy. Conclusions: Gemcitabine and nab-paclitaxel has a very promising antitumor activity in unresectable and borderline resectable pancreatic cancer patients. Investigation in a larger cohort of patients is ongoing. No significant financial relationships to disclose.