Sex determination in the blue tilapia (Oreochromis aureus) is thought to be a WZ-ZZ (female heterogametic) system controlled by a major gene. We searched for DNA markers linked to this major gene using the technique of bulked segregant analysis. We identified 11 microsatellite markers on linkage group 3 which were linked to phenotypic sex. The putative W chromosome haplotype correctly predicts the sex of 97% of male and 85% of female individuals. Our results suggest the W locus lies within a few centimorgans of markers GM354, UNH168, GM271 and UNH131. Markers onLG1 also showed a strong association with sex, and indicate the segregation of a male-determining allele in this region. Analysis of epistatic interactions among the loci suggests the action of a dominant male repressor (the W haplotype on LG 3) and a dominant male determiner (the Y haplotype on LG1). These markers have immediate utility for studying the strength of different sex chromosome alleles, and for identifying broodstock carrying copies of the W haplotype.

Lipocalins are involved in the binding of small molecules like sex steroids. We show here that the previously reported tilapia male-specific protein (MSP) is a lipocalin encoded by a variety of paralogous and homologous genes in different tilapia species. Exon-intron boundaries of MSP genes were typical of the six-exon genomic structure of lipocalins, and the transcripts were capable of encoding 200 amino-acid polypeptides that consisted of a putative signal peptide and a lipocalin domain. Cysteine residues are conserved in positions analogous to those forming the three disulfide bonds characteristic of the ligand pocket. The calculated molecular mass of the secreted MSP (20.4 kDa) was less than half of that observed, suggesting that it is highly glycosylated like its homologue tributyltin-binding protein. Analysis of sequence variations revealed three types of paralogs MSPA, MSPB and MSPC. Expression of both MSPA and MSPB was detected in testis. In haploid Oreochromis niloticus embryos, each of these types consisted of two closely related paralogs, and asymmetry between MSP copy numbers on the maternal (six copies) and the paternal (three copies) chromosomes was observed. Using this polymorphism we mapped MSPA and MSPC to linkage group 12 of an F 2 mapping family derived from a cross between O. niloticus and Oreochromis aureus. Females with high MSP copy number were more frequent by more than twofold than males. Gender-MSPC combinations showed significant deviation from expected Mendelian segregation (P ¼ 0.009) suggesting elimination of males with MSPC copies. We discuss different hypotheses to explain this elimination, including possibility for allelic conflict resulted by the hybridization.

SID530 is a new parenteral formulation of docetaxel containing hydroxypropyl-beta-cyclodextrin (HP-β-CD). In this study, a comparative pharmacokinetic study of 2 docetaxel parenteral solutions, SID530 and Taxotere, was carried out. In a crossover experimental design, 6 male cynomolgus monkeys received each formulation by intravenous infusion of a single dose. The concentration of docetaxel in whole blood and plasma was determined using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The 2 formulations showed similar pharmacokinetic parameters in both whole blood and plasma, and displayed comparable values for maximum serum concentration (Cmax), time to peak concentration (Tmax), and area under the concentration-time curve (AUC). The 90% confidence intervals for the ratios of Cmax and AUC values for SID530 to Taxotere were within the acceptable range of 0.80-1.20 in both plasma and whole blood. These findings indicate that SID530 and Taxotere are comparable in terms of their distribution in the blood and their plasma profile; consequently, these drugs are bioequivalent in the monkey.

A method based on frequency domain approaches is presented for the non-linear parameter identification of a structure having non-linear joints. The frequency response function (FRF) of the linear substructure, which can be calculated from the finite element method or measured by an experimental method, is used to calculate its FRFs needed in the parameter identification process. This method is easily applicable to a complex real structure having non-linear joints since it uses the FRF of the substructure. Since this method is performed in the frequency domain, the number of equations can be easily increased to as many as required to identify unknown parameters, not only by just varying the excitation amplitude but also by selecting the excitation frequencies. The validity of this method was tested numerically and experimentally with a cantilever beam having a non-linear element. It was verified through examples that the proposed method is useful to identify the non-linear joint parameters of a structure having arbitrary boundaries.