Quantitative trait loci for fatty acid composition in longissimus dorsi and abdominal fat: results from a White Duroc x Erhualian intercross F2 population

A whole-genome scan was performed on 660 F(2) animals including 250 barrows and 410 gilts in a White Duroc x Erhualian intercross population to detect quantitative trait loci (QTL) for fatty acid composition in the longissimus dorsi muscle and abdominal fat. A total of 153 QTL including 63 genome-wide significant QTL and 90 suggestive effects were identified for the traits measured. Significant effects were mainly evident on pig chromosomes (SSC) 4, 7, 8 and X. No association was detected on SSC3 and 11. In general, the QTL detected in this study showed distinct effects on fatty acid composition in the longissimus muscle and abdominal fat. The QTL for fatty acid composition in abdominal fat did not correspond to those identified previously in backfat and the majority of QTL for the muscle fatty acid composition were mapped to chromosomal regions different from previous studies. Two regions on SSC4 and SSC7 showed significant pleiotropic effects on monounsaturated (MUFA) and polyunsaturated fatty acid (PUFA) in both longissimus muscle and abdominal fat. Another two QTL with significant multi-faceted effects on MUFA and PUFA in the longissimus muscle were found each on SSC8 and SSCX. Chinese Erhualian alleles were associated with increased ratios of MUFA to saturated fatty acid at most of the QTL detected, showing beneficial effect in terms of human health.

Crystallization and preliminary X-ray analysis of the human respiratory syncytial virus nucleocapsid protein

Human respiratory syncytial virus (HRSV) has a nonsegmented negative-stranded RNA genome which is encapsidated by the HRSV nucleocapsid protein (HRSVN) that is essential for viral replication. HRSV is a common cause of respiratory infection in infants, yet no effective antiviral drugs to combat it are available. Recent data from an experimental anti-HRSV compound, RSV-604, indicate that HRSVN could be the target site for drug action. Here, the expression, purification and preliminary data collection of decameric HRSVN as well as monomeric N-terminally truncated HRSVN mutants are reported. Two different crystal forms of full-length selenomethionine-labelled HRSVN were obtained that diffracted to 3.6 and approximately 5 A resolution and belonged to space group P2(1)2(1)2(1), with unit-cell parameters a = 133.6, b = 149.9, c = 255.1 A, and space group P2(1), with unit-cell parameters a = 175.1, b = 162.6, c = 242.8 A, beta = 90.1 degrees , respectively. For unlabelled HRSVN, only crystals belonging to space group P2(1) were obtained that diffracted to 3.6 A. A self-rotation function using data from the orthorhombic crystal form confirmed the presence of tenfold noncrystallographic symmetry, which is in agreement with a reported electron-microscopic reconstruction of HRSVN. Monomeric HRSVN generated by N-terminal truncation was designed to assist in structure determination by reducing the size of the asymmetric unit. Whilst such HRSVN mutants were monomeric in solution and crystallized in a different space group, the size of the asymmetric unit was not reduced.

Intra- and inter-individual variability in measurements of biomarkers for oxidative damagein vivo: Nutrition and Breast Health Study

Oxidative stress has been implicated in the pathogenesis of various chronic diseases, such as cancer, cardiovascular disease and inflammatory conditions, as well as in ageing. Although a number of markers are now available, little is known about the reliability of single measurements of such markers in healthy individuals. The study examined the distribution of variance for three oxidative stress markers, 8-oxo-2'-deoxyguanosine (8-oxodG), 5-hydroxymethyl-2'-deoxyuridine (5-OHmdU) and total 8-isoprostane-F2alpha, which were measured every 3-6 months over 1 year in blood and breast nipple aspirate fluid (NAF) for 103 premenopausal women. For both plasma and NAF, the between-subject variances of 8-isoprostane-F2alpha were consistently greater than the within-subject variances. Consequently, their reliability coefficients were close to the level of those for cholesterol. On the other hand, the within-subject variances were much greater than the between-subjects variances for blood 5-OHmdU, resulting in low reliability coefficients, i.e. <0.3. Overall, the reliability coefficients for blood 8-oxodG were between those of 8-isoprostane-F2alpha and 5-OHmdU, but closer to those of 8-isoprostane-F2alpha. The results suggest that the reliability of oxidative stress markers may vary considerably depending on the type of marker. Caution should be exercised in selecting markers as well as in determining the number of study subjects or the number of samples per subject in a study. There also may be ample room to optimize laboratory techniques to quantify markers of oxidative DNA damage.

Characterization of the porcine Kisspeptins receptor gene and evaluation as candidate for timing of puberty in sows

Kisspeptins receptor (KISS1R), also called GPR54, is a key regulator of puberty in many species. KISS1R and its genetics in pigs remain unexplored. The objective of this study was to characterize the porcine KISS1R gene and evaluate the association of KISS1R mutations with age at puberty in sows. KISS1R was assigned to pig chromosome 2q21-24 by radiation hybrid mapping. It has a 1438 bp full-length cDNA and spans 3349 bp genomic sequence consisting of five exons and four introns. Semi-quantitative RT-PCR showed that KISS1R transcripts was particularly abundant in the adrenal, prostate, testis, thymus, pituary and hypothalamus. KISS1R mRNA content in the hypothalamus was determined by real-time quantitative RT-PCR, and it fluctuated during the oestrous cycle with the highest level in the luteal phase. Anoestrus sows had markedly lower hypothalamic KISS1R mRNA content than cyclic animals. Seven KISS1R SNPs were identified in the founder animals of a White Duroc x Erhualian intercross. One missense mutation (T/C(245)) showed quite different allele distribution in Chinese and Western breeds. All F(0), F(1) animals and 367 detailed phenotyped cyclic F(2) sows in the White Duroc x Erhualian intercross were genotyped for three KISS1R polymorphisms. No significant association of KISS1R haplotypes and haplotype pairs with age at puberty was observed in the resource population, indicating that mutations in KISS1R are not responsible for divergent age at puberty in White Duroc and Erhualian pigs.

Selection in the making: a worldwide survey of haplotypic diversity around a causative mutation in porcine IGF2

Domestic species allow us to study dramatic evolutionary changes at an accelerated rate due to the effectiveness of modern breeding techniques and the availability of breeds that have undergone distinct selection pressures. We present a worldwide survey of haplotype variability around a known causative mutation in porcine gene IGF2, which increases lean content. We genotyped 34 SNPs spanning 27 kb in 237 domestic pigs and 162 wild boars. Although the selective process had wiped out variability for at least 27 kb in the haplotypes carrying the mutation, there was no indication of an overall reduction in genetic variability of international vs. European local breeds; there was also no evidence of a reduction in variability caused by domestication. The haplotype structure and a plot of Tajima's D against the frequency of the causative mutation across breeds suggested a temporal pattern, where each breed corresponded to a different selective stage. This was observed comparing the haplotype neighbor-joining (NJ) trees of breeds that have undergone increasing selection pressures for leanness, e.g., European local breeds vs. Pietrain. These results anticipate that comparing current domestic breeds will decisively help to recover the genetic history of domestication and contemporary selective processes.

A methodology to model causal relationships on offshore safety assessment focusing on human and organizational factors

INTRODUCTION

Focusing on people and organizations, this paper aims to contribute to offshore safety assessment by proposing a methodology to model causal relationships.

METHOD

The methodology is proposed in a general sense that it will be capable of accommodating modeling of multiple risk factors considered in offshore operations and will have the ability to deal with different types of data that may come from different resources. Reason's "Swiss cheese" model is used to form a generic offshore safety assessment framework, and Bayesian Network (BN) is tailored to fit into the framework to construct a causal relationship model. The proposed framework uses a five-level-structure model to address latent failures within the causal sequence of events. The five levels include Root causes level, Trigger events level, Incidents level, Accidents level, and Consequences level. To analyze and model a specified offshore installation safety, a BN model was established following the guideline of the proposed five-level framework. A range of events was specified, and the related prior and conditional probabilities regarding the BN model were assigned based on the inherent characteristics of each event.

RESULTS

This paper shows that Reason's "Swiss cheese" model and BN can be jointly used in offshore safety assessment. On the one hand, the five-level conceptual model is enhanced by BNs that are capable of providing graphical demonstration of inter-relationships as well as calculating numerical values of occurrence likelihood for each failure event. Bayesian inference mechanism also makes it possible to monitor how a safety situation changes when information flow travel forwards and backwards within the networks. On the other hand, BN modeling relies heavily on experts' personal experiences and is therefore highly domain specific.

IMPACT ON INDUSTRY

"Swiss cheese" model is such a theoretic framework that it is based on solid behavioral theory and therefore can be used to provide industry with a roadmap for BN modeling and implications. A case study of the collision risk between a Floating Production, Storage and Offloading (FPSO) unit and authorized vessels caused by human and organizational factors (HOFs) during operations is used to illustrate an industrial application of the proposed methodology.

R-alpha-lipoic acid and acetyl-L-carnitine complementarily promote mitochondrial biogenesis in murine 3T3-L1 adipocytes

AIMS/HYPOTHESIS

The aim of the study was to address the importance of mitochondrial function in insulin resistance and type 2 diabetes, and also to identify effective agents for ameliorating insulin resistance in type 2 diabetes. We examined the effect of two mitochondrial nutrients, R-alpha-lipoic acid (LA) and acetyl-L-carnitine (ALC), as well as their combined effect, on mitochondrial biogenesis in 3T3-L1 adipocytes.

METHODS

Mitochondrial mass and oxygen consumption were determined in 3T3-L1 adipocytes cultured in the presence of LA and/or ALC for 24 h. Mitochondrial DNA and mRNA from peroxisome proliferator-activated receptor gamma and alpha (Pparg and Ppara) and carnitine palmitoyl transferase 1a (Cpt1a), as well as several transcription factors involved in mitochondrial biogenesis, were evaluated by real-time PCR or electrophoretic mobility shift (EMSA) assay. Mitochondrial complexes proteins were measured by western blot and fatty acid oxidation was measured by quantifying CO2 production from [1-14C]palmitate.

RESULTS

Treatments with the combination of LA and ALC at concentrations of 0.1, 1 and 10 micromol/l for 24 h significantly increased mitochondrial mass, expression of mitochondrial DNA, mitochondrial complexes, oxygen consumption and fatty acid oxidation in 3T3L1 adipocytes. These changes were accompanied by an increase in expression of Pparg, Ppara and Cpt1a mRNA, as well as increased expression of peroxisome proliferator-activated receptor (PPAR) gamma coactivator 1 alpha (Ppargc1a), mitochondrial transcription factor A (Tfam) and nuclear respiratory factors 1 and 2 (Nrf1 and Nrf2). However, the treatments with LA or ALC alone at the same concentrations showed little effect on mitochondrial function and biogenesis.

CONCLUSIONS/INTERPRETATION

We conclude that the combination of LA and ALC may act as PPARG/A dual ligands to complementarily promote mitochondrial synthesis and adipocyte metabolism.

Dynamic contrast-enhanced MRI of benign prostatic hyperplasia and prostatic carcinoma: correlation with angiogenesis

AIM

To investigate the diagnostic and differential diagnostic values of dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) in prostatic diseases, and to investigate the correlation between the parameters of SI-T curves and angiogenesis.

MATERIALS AND METHODS

Twenty-one patients with proven prostatic carcinoma (Pca) and 29 patients with proven benign prostatic hyperplasia (BPH) were examined using DCE MRI. Diagnostic characteristics for differentiation were examined using threshold values for maximum peak time, enhancement degree, and enhancement rate. Then, the signal intensity-time curves (SI-T curves) were analysed, and the correlations between the parameters of SI-T curves and the expression levels of vascular endothelial growth factor (VEGF) and microvascular density (MVD) were investigated. All patents underwent prostatectomy. DCE MRI and histological findings were correlated.

RESULTS

Pca showed stronger enhancement with an earlier peak time, higher enhancement, and enhancement rate (p<0.05). Regarding the type of SI-T curves, in the BPH group six were type A, 10 were type B, and 13 were type C, whereas in the Pca group, 14 were type A, six were type B, and only one was type C (Chi-square test, chi2=13.57, P<0.005). The VEGF and MVD expression levels of Pca were higher than those of BPH. Peak time was negatively correlated with the expression levels of VEGF and MVD, whereas the enhancement degree and enhancement rate showed positive correlations (Pearson correlation, p<0.05).

CONCLUSION

Based on T2-weighted imaging, DCE MRI curves can help to differentiate benign from malignant prostate tissue. In the present study the type C curve was rarely seen with malignant disease, but these results need confirmation.

A novel calcium-sensitive potassium conductance is coupled to P2X3 subunit containing receptors in myenteric neurons of guinea pig ileum

This study characterized P2X receptors in guinea pig ileum myenteric S neurons (n = 124) in vitro using electrophysiological methods. ATP or alpha,beta-methylene ATP (alpha,beta-mATP), an agonist at P2X(1) and P2X(3) subunit containing receptors, depolarized 103 neurons (85%). Pyridoxal-phosphate-6-azophenyl-2',4' disulfonic acid (10 micromol L(-1)) blocked ATP- and alpha,beta-mATP-induced depolarizations. ATP-induced depolarizations and fast excitatory postsynaptic potentials (fEPSPs) were reduced by trinitrophenyl-ATP (10 micromol L(-1)), an antagonist that can block P2X(3) receptors. Ivermectin (10 micromol L(-1)), a modulator of P2X(4) and P2X(4/6) receptors, had no effect on alpha,beta-mATP-induced depolarizations. In 58% of neurons, the alpha,beta-mATP induced-depolarization was followed by an afterhyperpolarization (AHP) (P2X-AHP). Under voltage clamp, alpha,beta-mATP induced an inward current followed by an outward current which reversed polarity at 0 and -80 mV respectively. The P2X-AHP was reduced in low extracellular Ca(2+) solutions. Blockers of large, intermediate and small conductance Ca(2+)-activated K(+) channels or voltage-gated K(+) channels did not inhibit the P2X-AHP. Half of the neurons exhibiting the P2X-AHP contained nitric oxide synthase (NOS)-immunoreactivity (ir). In summary, NOS-ir S neurons express P2X(3) subunit containing P2X receptors. P2X receptors couple to activation of a Ca(2+)-activated K(+) conductance that mediates an AHP. As P2X receptors contribute to fEPSPs, the P2X-AHP may modulate S neuron excitability during purinergic synaptic transmission.

The costs and benefits of reforestation in Liping County, Guizhou Province, China

Reducing greenhouse gases in the atmosphere is becoming a pressing issue for the global community. Afforestation and reforestation are promoted worldwide as an effective means of sequestering carbon. For its national interest and global concerns, China has made great efforts to protect its existing forests and develop programs of afforestation and reforestation. Based on two surveys recently conducted in Liping County, Guizhou province, this paper investigates the economic changes associated with the implementation of the "Grain For Green" policy. Based on the analytical framework of benefit cost analysis, this paper concludes that the implementation of the reforestation of sloping agricultural land policy would not be possible if there were no government subsidies for the peasants. The short term economic returns of land and labour from forestation are substantially lower than those generated from grain or cash crop production on the steep slope lands. The government subsidies provide great economic incentives for peasants to take part in the project. The subsidies in fact have elevated peasant income in rural Liping. The estimated potential economic returns of plantations over the long run indicate that the removal of the government financial subsidies would not create an economic crisis for the peasants if the current market conditions continue.

Characterization of the porcine insulin-like growth factor-binding protein, acid-labile subunit gene: full-length cDNA and DNA sequence, polymorphisms and expression profile

Insulin-like growth factor-binding protein acid-labile subunit (IGFALS) is an important glycoprotein in the circulation complex for insulin-like growth factors-I and -II (IGFs). So far only a partial porcine IGFALS sequence is available. We herein report the isolation, characterization, polymorphism identification and expression analysis of the porcine IGFALS gene. A 2000-bp full-length cDNA sequence was determined with 5'- and 3'-Rapid Amplification of cDNA End (RACE) assay. It contains a 1821-bp open reading frame encoding a protein of 606 amino acids with a calculated molecular mass of 66 kDa and a theoretical isoelectric point of 6.89. The deduced IGFALS protein shares high identity (70-80%) with other mammalian IGFALS. We also obtained a full-length genomic DNA sequence of the gene. Similar to the other mammalian orthologues, particularly in terms of exon size and exon/intron boundaries, the porcine IGFALS gene spans a transcription unit of 2990 bp, consisting of two exons and one intron. Three single nucleotide polymorphisms (synonymous mutations) were identified in the DNA sequence. RT-PCR assays indicate that IGFALS is expressed ubiquitously in pigs and transcripts are particularly abundant in the liver, lung, white adipose tissue, prostate, epididymis, thyroid and bladder.

The g.243A>G mutation in intron 17 of MUC4 is significantly associated with susceptibility/resistance to ETEC F4ab/ac infection in pigs

Using a porcine radiation hybrid panel, we assigned the mucin 4 (MUC4) gene to SSC13q41, which harbours the enterotoxigenic Escherichia coli (ETEC) F4ab/ac receptor locus. In addition, we identified two SNPs in intron 17 of MUC4 (DQ124298:g.243A>G and DQ124298:g.334A>G) in the parental population of a White Duroc x Erhualian cross. Association analysis showed that the MUC4 g.243A>G mutation was strongly associated with ETEC F4ab/ac, and especially with F4ac adhesion phenotypes in the White Duroc x Erhualian resource population, indicating that this polymorphism was in a significant linkage disequlibrium with the ETEC F4ab/ac receptor locus. Because of different linkage disequlibrium values between the ETEC F4ab and F4ac adhesion phenotypes and the MUC4 g.243A>G mutation, we argue that the inheritance of F4ab and F4ac receptors might be under the control of two closely linked loci.

Characterization of polymorphisms of transferrin receptor and their association with susceptibility to ETEC F4ab/ac in pigs

Diarrhoea caused by enterotoxigenic Escherichia coli (ETEC) expressing F4 (F4ab, F4ac and F4ad) fimbriae is a significant cause of mortality and morbidity in newborn and weaned pigs. The locus controlling susceptibility towards ETEC F4ab/ac has been mapped to SSC13q41, in which TFRC (transferrin receptor) was localized and considered as a positional candidate gene for ETEC F4ab/ac receptor. In this study, we determined susceptibility/resistance to ETEC F4ab/ac in a total of 755 F2 animals from a White Duroc x Erhualian intercross using a microscopic enterocyte adhesion assay. We identified two TFRC polymorphisms (SNPs 591 A>G and 632 A>G) in a single exon after comparative sequencing analysis of 2371-bp amplicons containing the complete coding region of TFRC using RNA of eight full-sib F2 animals with susceptible and resistant phenotypes. The intron sequences flanking the two exon polymorphisms were obtained, revealing an intron polymorphism (SNP 291 C>T). We genotyped the 19 founder animals of the White Duroc x Erhualian intercross for the identified polymorphisms, showing that only the 291 C>T polymorphism is a highly informative marker. We further genotyped all 59 F1 and 755 F2 animals for the 291 C>T polymorphism, and the association of this polymorphism with susceptibility/resistance to ETEC F4ab/ac in these F2 animals was evaluated by the transmission disequilibrium test. The result showed that the 291 C>T polymorphism is not a causal mutation, however, has a significant linkage disequilibrium with the ETEC F4ab/ac, especially F4ac receptor locus.

Impairments in deeply-saturated optical parametric amplifiers for amplitude- and phase-modulated signals

We measure impairment of on-off-keyed and differential-phase-shift-keyed signals imposed by gain saturation in a fiber parametric amplifier. Phase modulation is observed to be more robust, particularly for deep (15 dB) saturation.

Preparation and Properties of Poly(lactide-co-glycolide) (PLGA)/ Nano-Hydroxyapatite (NHA) Scaffolds by Thermally Induced Phase Separation and Rabbit MSCs Culture on Scaffolds

Biodegradable polymer/bioceramic composites scaffold can overcome the limitation of conventional ceramic bone substitutes such as brittleness and difficulty in shaping. To better mimic the mineral component and the microstructure of natural bone, novel nano-hydroxyapatite (NHA)/polymer composite scaffolds with high porosity and well-controlled pore architectures as well as high exposure of the bioactive ceramics to the scaffold surface is developed for efficient bone tissue engineering. In this article, regular and highly interconnected porous poly(lactide-co-glycolide) (PLGA)/NHA scaffolds are fabricated by thermally induced phase separation technique. The effects of solvent composition, polymer concentration, coarsening temperature, and coarsening time as well as NHA content on the micro-morphology, mechanical properties of the PLGA/NHA scaffolds are investigated. The results show that pore size of the PLGA/NHA scaffolds decrease with the increase of PLGA concentration and NHA content. The introduction of NHA greatly increase the mechanical properties and water absorption ability which greatly increase with the increase of NHA content. Mesenchymal stem cells are seeded and cultured in three-dimensional (3D) PLGA/NHA scaffolds to fabricate in vitro tissue engineering bone, which is investigated by adhesion rate, cell morphology, cell numbers, and alkaline phosphatase assay. The results display that the PLGA/NHA scaffolds exhibit significantly higher cell growth, alkaline phosphatase activity than PLGA scaffolds, especially the PLGA/NHA scaffolds with 10 wt.% NHA. The results suggest that the newly developed PLGA/NHA composite scaffolds may serve as an excellent 3D substrate for cell attachment and migration in bone tissue engineering.

Blockage of intermediate-conductance-Ca(2+) -activated K(+) channels inhibits progression of human endometrial cancer

Potassium (K(+)) channels have been implicated in proliferation of some tumor cells. However, whether K(+) channels are important to the pathogenesis of endometrial cancer (EC) remains unknown. In the present study, we report that intermediate-conductance Ca(2+)-activated K(+) (IKCa1) channels play a critical role in the development of EC. The expression of IKCa1 at both mRNA and protein levels in EC tissues was greatly increased than that in atypical hyperplasia and normal tissues. Treatment of EC cells with clotrimazole and TRAM-34, two agents known to inhibit IKCa1 channels, suppressed the proliferation of EC cells and blocked EC cell cycle at G(0)/G(1) phase. Similarly, downregulation of IKCa1 by siRNA against IKCa1 inhibited EC cell proliferation and arrested its cell cycle at G(0)/G(1) phase. A clotrimazole-sensitive K(+) current was induced in EC cells in response to the increased Ca(2+). The current density induced by Ca(2+) was greatly reduced by clotrimazole, TRAM-34, charybdotoxin or downregulation of IKCa1 by the siRNA against IKCa1. Furthermore, TRAM-34 and clotrimazole slowed the formation in nude mice of tumor generated by injection of EC cells. Our results suggest that increased activity of IKCa1 channel is necessary for the development of EC.

Biological activities of a novel selective oestrogen receptor modulator derived from raloxifene (Y134)

BACKGROUND AND PURPOSE

Selective oestrogen receptor (ER) modulators (SERMs) are of great value in the treatment of breast cancer and osteoporosis. The aim of this study was to characterize pharmacologically a new class of SERMs synthesized based on the core structure of raloxifene.

EXPERIMENTAL APPROACH

Competitive receptor binding and luciferase-based reporter methods were used to study the bioactivities of raloxifene analogues, followed by efficacy determination in breast cancer cell proliferation assay. ER antagonist effects were investigated in female rats by measuring uterine and mammary gland growth, using wet weight, BrdU incorporation and terminal end bud (TEB) as indicators.

KEY RESULTS

Five analogues, belonging to two different structural series and display higher binding affinities for ERalpha than ERbeta were functionally evaluated. One such analogue, Y134, exhibited potent antagonist activity at ERs in CV-1 cells cotransfected with plasmids containing ERalpha or ERbeta and oestrogen-response element-driven luciferase. The estimated IC(50) value was 0.52 nM for ERalpha and 2.94 nM for ERbeta, comparable to that of raloxifene. Little cytotoxicity was observed at Y134 concentrations below 10 microM. Y134 suppressed oestrogen-stimulated proliferation of ER-positive human breast cancer MCF-7 and T47D cells. At an identical dose, administered to ovariectomized rats, Y134 was more effective than raloxifene at arresting oestrogen-induced outgrowth of TEB and mammary gland DNA synthesis, but their inhibitory effects on the uterus were comparable.

CONCLUSIONS AND IMPLICATIONS

Y134 is a potent ER antagonist with better mammary gland selectivity than raloxifene and shows potential for development as a new SERM for therapeutic use.

A pilot study of weekly versus 3-week docetaxel in combination with capecitabine in patients with anthracycline-pretreated metastatic breast cancer

10771

Background: Capecitabine in combination with docetaxel given every 3 weeks has shown a high degree of activity in anthracycline-pretreated metastatic breast cancer (MBC), but with high toxicities. To improve the therapeutic index, we performed a clinical pilot trial to evaluate the efficacy and safety of weekly or 3-week docetaxel in combination with capecitabine given for 14 days every 21 days. Methods: Patients with at least one measurable lesion were randomized to receive the treatment arms: docetaxel 75mg/m2 on days 1, oral capecitabine 950 mg/m2 twice daily on days 1–14 (Arm A); docetaxel 37.5mg/m2 on days 1 and 8, oral capecitabine 950 mg/m2 twice daily on days 1–14 (arm B). Each cycle was repeated every 3 weeks. Patients remained on study for a maximum 6 cycles or until tumor progression or unacceptable toxicity occurred, response assessments were scheduled every two cycles. Results: 64 pts were enrolled, 62 eligible for safety and tumor assessment. Key baseline variables were well balanced. Dominant site of disease was visceral in 66.1%; 24.2% had ≥3 organ sites of disease; all patients had previously received anthracyclines, 24.2% for MBC. 43. 6% were ER negative and 46.8% were HER-2 overexpress. The overall clinical response rate of all groups was 59.7% (37/62). There was no progressive disease (PD) after two cycles. Efficacy outcomes were similar in the two arms. The response rate of group A and B were 60% (18/30) and 59.4% (19/32) respectively. There were no drug-related deaths observed. Neutropenia was the most common toxicity. In all, the frequence of Grade 3/4 neutropenia were similar in two arm, but Grade 4 neutropenia of Group A 66.7% (20/30) was higher than Group B 34.4% (11/32), P = 0.021. Conclusions: The study confirmed the superior activity of docetaxe-capecitabine combination therapy in anthracycline resistant MBC, and comparing with 3-week schedule, weekly docetaxel plus capecitabine has same high efficacy with a favourable safety profile.

No significant financial relationships to disclose.

Study of brain and whole blood PK/PD of bortezomib in rat models

12036

Background: Bortezomib (Btz) is the first in class proteasome inhibitor and has been approved for treatment of multiple myeloma patients who have received at least 1 prior therapy. The potential for Btz to penetrate the CNS was examined in the rat under two conditions: intact blood brain barrier (BBB) and compromised BBB induced by middle cerebral artery occlusion (MCAO). Methods: Intact BBB: healthy rats received an iv bolus followed by a constant infusion of Btz to steady-state (SS). The blood and brain samples were collected for determination of concentration (Conc) of Btz (PK) and of 20S proteasome activity (PD). The brain samples were collected after a perfusion with saline. Inulin was included in the study in order to determine blood contamination in brain tissues. Compromised BBB: rats underwent MCAO surgery and 1 h later were administered Btz via an iv bolus of 0, 0.1, 0.2 or 0.35 mg/kg. The blood and brain samples were collected through 24 h postdose. Conc of Btz was determined by an LC/MS/MS method. The 20S proteasome activity was measured using an ex vivo assay. Results: 1) Intact BBB: at SS the mean blood Conc of Btz was 140 ng/mL, and proteasome activity in the blood was inhibited by ∼80% compared to the vehicle group (p < 0.0001). In contrast, the brain Conc of Btz was extremely low (∼3 ng/g) with the brain-to-blood ratio of ∼0.02. No difference was observed in brain proteasome activity between the vehicle and Btz-treated groups. 2)The MCAO rat: the PK/PD relationship in the blood was best described by a sigmoid Emax model with an EC50 of 110 ng/mL and gamma factor of 3.8. The model also suggests that there is no proteasome inhibition (PI) when the blood Conc is <40 ng/mL (no effective blood Conc, NOEBC). In the brain, the Cmax of Btz was 22.0 ng/g from the highest dose group, in contrast to the blood Cmax of 164 ng/mL. The increased exposure in the brain of a MCAO rat relative to a normal rat was anticipated as its BBB is impaired. However, the brain Concs were all below the NOEBC. No significant PI was observed in all brain tissues (P>0.1). Conclusion: Very poor brain penetration was observed for Btz in rats. Btz showed PI in whole blood but not in the brain either of normal or MCAO rats following administration of Btz.

[Table: see text]