Validated HPLC Method for the Determination of Paclitaxel-related Substances in an Intravenous Emulsion Loaded with a Paclitaxel-Cholesterol Complex

A high-performance liquid chromatography method was developed for the determination of related substances in an intravenous emulsion loaded with a paclitaxel-cholesterol complex. The separation was achieved using Agilent Eclipse XDB-C18 column (150×4.6 mm, 3.5 μm), which was kept at 40°. The gradient mobile phase consisted of acetonitrile and water with a flow rate of 1.2 ml/min. The ultraviolet detection wavelength was set at 227 nm. The preparation of the sample solution began with the addition of anhydrous sodium sulphate to break the emulsion. Then, methanol and ethyl ether were added to pick up the drug and remove the accessories of the emulsion by extraction and centrifugation. Finally, paclitaxel was enriched by a nitrogen blow method and resolved with a mixture of methanol:glacial acetic acid (200:1). The method was proven to be selective, sensitive, robust, linear, repeatable, accurate and suitable for the determination of paclitaxel-related substances in the emulsion formulations, and the major degradation products in the potential pharmaceutical product were 7-epipaclitaxel and 10-deacetylpaclitaxel.

Prognostic significance of apical lymph node metastasis in patients with node-positive rectal cancer

AIM

The aim of this study was to assess the effect of apical lymph node (APN) metastasis in predicting prognosis in curatively treated node-positive rectal cancer. We also investigated the relationship between APN metastasis and the total number of metastatic lymph nodes.

METHOD

A retrospective study was performed of 510 curatively treated patients with node-positive rectal cancer. Clinicopathological variables, including APN status, were assessed in univariate and multivariate analyses. The prognostic significance of APN status in predicting patient outcomes and the relationship between APN status and American Joint Committee on Cancer (AJCC) N stage were analysed.

RESULTS

At a median follow up of 47 months, the 5-year local recurrence (LR) rate, the disease-free survival (DFS) rate and the overall survival (OS) rate were 18.3%, 55.5% and 58.8%, respectively. The 5-year OS rate was 69.6% for patients with no metastasis in APNs (APN(-)) and 40.8% for patients with metastasis in APNs (APN(+)). DFS and OS for patients with undetermined APN status were between those for APN(-) and APN(+). Subgroup analysis gave a 5-year OS rate of 48.7% in Stage N1 patients with APN(+) and 58.8% for Stage N2 patients with APN(-) (P = 0.0004).

CONCLUSION

APN metastasis is an important prognostic factor in node-positive rectal cancer, which provides additional survival-related prognostic classification irrespective of N stage. As the APN is usually outside the radiation field, in the era of multidisciplinary treatment its assessment should be incorporated into prognostic evaluation of rectal cancer.

PIKE mediates EGFR proliferative signaling in squamous cell carcinoma cells

One of the key drivers for squamous cell carcinoma (SCC) proliferation is activation of the epidermal growth factor receptor (EGFR), a known proto-oncogene. However, the mechanism of EGFR-dependent SCC proliferation remains unclear. Our previous studies indicate that epidermal growth factor (EGF)-induced SCC cell proliferation requires the SH3 domain of phospholipase C-γ1 (PLC-γ1), but not its catalytic activity. The SH3 domain of PLC-γ1 is known to activate the short form of nuclear phosphatidylinositol 3-kinase enhancer (PIKE) that enhances the activity of nuclear class Ia phosphatidylinositol 3-kinase (PI3K) required for proliferation. However, PIKE has been described for more than a decade to be present exclusively in neuronal cells. In the present study, we found that PIKE was highly expressed in malignant human keratinocytes (SCC4 and SCC12B2) but had low expression in normal human keratinocytes. Immunohistochemical analysis showed strong nuclear staining of PIKE in human epidermal and tongue SCC specimens but little staining in the adjacent non-cancerous epithelium. Treatment of SCC4 cells with EGF-induced translocation of PLC-γ1 to the nucleus and binding of PLC-γ1 to the nuclear PIKE. Knockdown of PLC-γ1 or PIKE blocked EGF-induced activation of class Ia PI3K and protein kinase C-ζ and phosphorylation of nucleolin in the nucleus as well as EGF-induced SCC cell proliferation. However, inhibition of the catalytic activity of PLC-γ1 had little effect. These data suggest that PIKE has a critical role in EGF-induced SCC cell proliferation and may function as a proto-oncogene in SCC.

Development and comparison of a new personalized warfarin stable dose prediction algorithm in Chinese patients undergoing heart valve replacement

BACKGROUND

Pharmacogenetics-based algorithms would be especially desirable for patients undergoing heart valve replacement (HVR), who are particularly sensitive to warfarin during the initial treatment phase following surgery. We aimed to derive a warfarin dosing algorithm from data of Chinese patients undergoing HVR, and to compare it with previously published dosing algorithms as applied to our HVR patients.

METHODS

641 Chinese HVR patients on stable maintenance dose of warfarin were enrolled from a single clinic site. Data of 321 patients were used to derive a warfarin dosing algorithm using stepwise multiple linear regression analysis. Previously published algorithms were selected from Pubmed database for comparison. The performance of all the algorithms was characterized according to mean absolute error (MAE) and percentage of predicted doses falling within +/- 20% of clinically observed doses (percentage of ideal prediction) in the other 320 patients.

RESULTS

The newly developed algorithm included eight factors: VKORC1-1639G > A, CYP2C9*3, BSA, age, number of increasing INR drugs, smoking habit, preoperative stroke history and hypertension. Our algorithm accounted for 56.4% of variations in the inter-patient warfarin stable doses. All the algorithms showed better performance in a medium-dose (1.88-4.38 mg/day) and high-dose (> or = 4.38 mg/day) groupings than in a low-dose (< or = 1.88 mg/day) grouping. Compared with the 14 previously published algorithms, our algorithm had the lowest MAE (-0.07 mg/day) and the highest percentage of ideal prediction (62.8%) in the total validation cohort.

CONCLUSIONS

Our warfarin dosing algorithm is potentially useful for patients whose population profiles are similar to those of our patients.

Polymorphism identification in the goat <i>THRSP</i> gene and association analysis with growth traits

Abstract. cIn this study, we reported the analysis of THRSP gene polymorphisms in 610 goats of three breeds: Xinong Saanen (SN), Guanzhong (GZ) and Boer (BG). We identified new allelic variant: P2-G39294A (GenBank acc. no. JN618075) in the three goat breeds. At P2 locus, GG, GA and AA genotypes were found in the three goat breeds. The frequencies of G allele were 0.54–0.55 and frequencies of A allele were 0.46–0.45, and the PIC was 0.37. The SNP locus was in Hardy-Weinberg disequilibrium in Boer goat breed (P<0.05). Association of polymorphisms with growth traits was done at P2 locus in Boer goat breed. The result showed that AA genotype had remarkable growth traits at P2 locus (P<0.05). Therefore, these results suggest that THRSP gene is a strong candidate gene that affects growth traits in goat.

The role of nisin in fuel ethanol production with Saccharomyces cerevisiae

AIMS

To investigate the effects of nisin on lactobacilli contamination of yeast during ethanol fermentation and to determine the appropriate concentration required to control the growth of selected lactobacilli in a YP/glucose media fermentation model.

METHODS AND RESULTS

The lowest concentration of nisin tested (5 IU ml(-1) ) effectively controlled the contamination of YP/glucose media with 10(6) CFU ml(-1) lactobacilli. Lactic acid yield decreased from 5.0 to 2. 0 g l(-1) and potential ethanol yield losses owing to the growth and metabolism of Lactobacillus plantarum and Lactobacillus brevis were reduced by 11 and 7.8%, respectively. Approximately, equal concentrations of lactic acid were produced by Lact. plantarum and Lact. brevis in the presence of 5 and 2 IU ml(-1) nisin, respectively, thus demonstrating the relatively higher nisin sensitivity of Lact. brevis for the strains in this study. No differences were observed in the final ethanol concentrations produced by yeast in the absence of bacteria at any of the nisin concentrations tested.

CONCLUSIONS

Metabolism of contaminating bacteria was reduced in the presence of 5 IU ml(-1) nisin, resulting in reduced lactic acid production and increased ethanol production by the yeast.

SIGNIFICANCE AND IMPACT OF THE STUDY

Bacteriocins represent an alternative to the use of antibiotics for the control of bacterial contamination in fuel ethanol plants and may be important in preventing the emergence of antibiotic-resistant contaminating strains.

SU-E-T-154: Online Dose Verification with Gafchromic Film for Fixed-Gantry and Rotational Intensity Modulated Radiation Therapy: A Phantom Study

PURPOSE

The patient specific quality assurance (QA) measurements for fixed-gantry and rotational intensity modulated radiation therapy (IMRT and VMAT/RapidArc) are usually performed on a homogeneous phantom prior to the treatment. The purpose of this study is to develop an online method to verify the delivered dose to the patient on the treatment day.

METHODS

An anthropomorphic (Rando) head phantom was immobilized in treatment position with a thermoplastic mask to simulate a real patient. A sheet of gafchromic film (EBT2) was sandwiched between a 1-cm-thick solid water slab, which was fixed to the Type-S extension board, and the patient's head hold (a pillow used here). The CT images of the Rando phantom were acquired and exported to the treatment planning systems. One step-and-shot fixed-gantry IMRT plan and one RapidArc plan were generated and the dose distributions on the film plane were calculated. The two plans were delivered to the patient (Rando phantom in this study) in the treatment position on a Varian Trilogy linear accelerator with two new films. The films were scanned, and the measurements were compared with the planned doses.

RESULTS

The composite dose distributions measured on the film plane were the actual delivered dose for the treatment. The comparison between the measurement and planned dose profiles shows an agreement within 3% because of the good reproducibility of phantom positioning. Gamma pass rates (using 3mm and 3% criteria) for the IMRT and RapidArc plan were found to be 95% and 94%, respectively.

CONCLUSIONS

The phantom study has demonstrated the feasibility of using gafchromic film for online dose verification. This simple method takes into account the patient heterogeneity and the treatment associated uncertainties such as setup error, intrafraction motions and machine related variations. It can be implemented as an online physics and/or clinical QA tool without taking additional machine time.

Lung spirometry parameters and diffusion capacity are decreased in patients with Type 2 diabetes

AIMS

In cohort studies, Type 2 diabetes mellitus has been associated with decreased forced 1 s expiratory volume and forced vital capacity. We examined if forced vital capacity, forced 1 s expiratory volume and diffusion lung capacity correlate with diabetes mellitus across different races in a clinical setting.

METHODS

We examined the medical records of 19,882 adults 18-97 years of age in our centre from 1 January 2000 to 1 May 2009. After excluding patients with diseases causing abnormal lung function, 4164 subjects were available for analysis. We used multiple linear regressions to examine cross-sectional differences in forced vital capacity, forced 1 s expiratory volume and carbon monoxide diffusing capacity between patients with and without diabetes mellitus, after adjustment for age, sex, race, height, smoking, BMI and heart failure.

RESULTS

Patients with diabetes (n = 560) were older (62 ± 12 vs. 55 ± 16 years), more likely to be men (56 vs. 43%), overweight (BMI 31.7 ± 8.5 vs. 27.3 ± 6.7 kg/m2 ), have heart failure (33 vs. 14%) and less likely to be Caucasians (65 vs. 76%) and never smokers (66 vs. 72%) compared with patients without diabetes (n = 3604). The mean unadjusted values in patients with diabetes vs. those without were: forced vital capacity 2.78 ± 0.91 vs. 3.19 ± 1.03 l; forced 1 s expiratory volume 2.17 ± 0.74 vs. 2.49 ± 0.0.83; and carbon monoxide diffusing capacity 16.67 ± 5.53 vs. 19.18 ± 6.72 ml(-1) min(-1) mmHg, all P < 0.0001. These differences remained significant after adjustment for covariates. After race stratification, only Caucasians with diabetes had a significant decrease in all lung function measures.

CONCLUSIONS

Patients with diabetes have decreased lung function compared with those without diabetes. Caucasians with diabetes have more global lung function impairment compared with African-Americans and Hispanics.

Microarray profiling analysis uncovers common molecular mechanisms of rubella virus, human cytomegalovirus, and herpes simplex virus type 2 infections in ECV304 cells

To study the common molecular mechanisms of various viruses infections that might result in congential cardiovascular diseases in perinatal period, changes in mRNA expression levels of ECV304 cells infected by rubella virus (RUBV), human cytomegalovirus (HCMV), and herpes simplex virus type 2 (HSV-2) were analyzed using a microarray system representing 18,716 human genes. 99 genes were found to exhibit differential expression (80 up-regulated and 19 down-regulated). Biological process analysis showed that 33 signaling pathways including 22 genes were relevant significantly to RV, HCMV and HSV-II infections. Of these 33 biological processes, 28 belong to one-gene biological processes and 5 belong to multiple-gene biological processes. Gene annotation indicated that the 5 multiple-gene biological processes including regulation of cell growth, collagen fibril organization, mRNA transport, cell adhesion and regulation of cell shape, and seven down- or up-regulated genes [CRIM1 (cysteine rich transmembrane BMP regulator 1), WISP2 (WNT1 inducible signaling pathway protein 2), COL12A1 (collagen, type XII, alpha 1), COL11A2 (collagen, type XI, alpha 2), CNTN5 (contactin 5), DDR1 (discoidin domain receptor tyrosine kinase 1), VEGF (vascular endothelial growth factor precursor)], are significantly correlated to RUBV, HCMV and HSV-2 infections in ECV304 cells. The results obtained in this study suggested the common molecular mechanisms of viruses infections that might result in congential cardiovascular diseases.

P3-16-17: The Identification of Novel Microtubule Stabilizing Taccalonolides

Microtubule stabilizing agents, including the taxanes and epothilones, are some of the most important drugs used in the treatment of cancer. All of the microtubule stabilizers used clinically bind within the taxane site on microtubules and work through a similar mechanism of action. We have identified a new class of microtubule stabilizers, the taccalonolides, from plants of the genus Tacca. The most abundant taccalonolides, A and E, are classified as microtubule stabilizers due to their ability to disrupt both interphase and mitotic cellular microtubules, leading to mitotic arrest and apoptosis. However, they are unique from all other microtubule stabilizers in that they do not bind directly to microtubules or stimulate the polymerization of tubulin in biochemical preparations. The taccalonolide structure is characterized by a highly acetylated pentacyclic steroidal skeleton, which is also structurally distinct from all other microtubule targeted agents. The unique structure and mechanism of action of the taccalonolides, together with their ability to circumvent clinically relevant forms of taxane resistance, prompted our efforts to explore the structure-activity relationship of this class of molecules. We have isolated several novel taccalonolides, designated Z, AA, AB, AC, AF and AG, as well as multiple known taccalonolides. Each of these taccalonolides exhibited cellular microtubule stabilizing activity and antiproliferative actions against breast cancer cells. However, profound differences in potencies were noted with IC50 values ranging from 32 nM to 13 μM. These studies demonstrate that microtubule stabilizing activity is a shared trait among this class of molecules and that significant structure-activity relationships exist. Additionally, in vivo antitumor evaluations of taccalonolides A, E and N demonstrate that each of these molecules has activity in vivo and that taccalonolide A is the most effective against a syngeneic mammary model of breast cancer.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-16-17.

Polygamain, a new microtubule depolymerizing agent that occupies a unique pharmacophore in the colchicine site

Bioassay-guided fractionation was used to isolate the lignan polygamain as the microtubule-active constituent in the crude extract of the Mountain torchwood, Amyris madrensis. Similar to the effects of the crude plant extract, polygamain caused dose-dependent loss of cellular microtubules and the formation of aberrant mitotic spindles that led to G(2)/M arrest. Polygamain has potent antiproliferative activities against a wide range of cancer cell lines, with an average IC(50) of 52.7 nM. Clonogenic studies indicate that polygamain effectively inhibits PC-3 colony formation and has excellent cellular persistence after washout. In addition, polygamain is able to circumvent two clinically relevant mechanisms of drug resistance, the expression of P-glycoprotein and the βIII isotype of tubulin. Studies with purified tubulin show that polygamain inhibits the rate and extent of purified tubulin assembly and displaces colchicine, indicating a direct interaction of polygamain within the colchicine binding site on tubulin. Polygamain has structural similarities to podophyllotoxin, and molecular modeling simulations were conducted to identify the potential orientations of these compounds within the colchicine binding site. These studies suggest that the benzodioxole group of polygamain occupies space similar to the trimethoxyphenyl group of podophyllotoxin but with distinct interactions within the hydrophobic pocket. Our results identify polygamain as a new microtubule destabilizer that seems to occupy a unique pharmacophore within the colchicine site of tubulin. This new pharmacophore will be used to design new colchicine site compounds that might provide advantages over the current agents.

Detection of incidental colorectal tumours with 18F-labelled 2-fluoro-2-deoxyglucose positron emission tomography/computed tomography scans: results of a prospective study

AIM

This study assessed the clinical significance of incidental colorectal 2-fluoro-2-deoxyglucose (FDG) uptake using (18) F-FDG positron emission tomography/computed tomography (PET/CT) scans and evaluated the importance of colonoscopy when incidental colorectal FDG uptake was observed.

METHOD

A prospective study was designed and conducted at a single institution over a 2-year period. In patients undergoing PET/CT scans, all with FDG uptake in the colorectum were assigned to have colonoscopy and biopsy. The value of PET/CT scanning was studied by comparison with the colonoscopy and biopsy results.

RESULTS

Among 10,978 PET/CT scans, one or more focal uptakes of FDG in the colorectum were observed in 148 (1.35%) patients. In 136 valid patients, malignant colorectal tumours and polyps were found in 23.5% and 20.5%, respectively,, while the colon in the other 56% was normal. A higher false-positive rate was found in the right colon compared with the distal colorectum (66.2%vs 36.7%, P = 0.004). A significant increase of the maximum standardized uptake (SUVmax) value was found among normal, polyps and cancer groups. Multivariate analysis revealed that SUVmax was the risk factor for predicting colorectal cancer or polyps and FDG uptake in the right colon was a negative predictive factor for finding cancers or polyps.

CONCLUSIONS

Our study proves the necessity of colonoscopy when incidental FDG uptake is found on PET/CT imaging. The false-positive FDG uptake is more commonly observed in the right colon. Although the SUVmax value is higher in cancer patients, a high SUVmax value does not necessarily result in malignancies.

Emu model of full-range femoral head osteonecrosis induced focally by an alternating freezing and heating insult

The emu, a large bipedal bird with hip joint biomechanics similar to humans, was used to establish an experimental model of femoral head osteonecrosis and subsequent femoral head collapse. Focal lesions were induced in 20 adult male emus using an alternating liquid nitrogen freezing and radiofrequency heating insult. At 2, 4, 8, 12 and 16 weeks post-surgery, hip magnetic resonance imaging (MRI) was performed. Before the emus were sacrificed, barium sulphate was infused to the lower extremity to study blood vessel distribution patterns. Femoral samples were scanned by micro-computed tomography (micro-CT) and evaluated histologically. Hip MRI showed changes from broad oedema to femoral head collapse. Emus developed a crippled gait from post-operative week 6. Micro-CT scans and histology showed human-like osteonecrotic changes with an impaired local blood supply. The protocol resulted in consistent full-range osteonecrosis of the femoral head that may serve as a model for testing potential treatments.