We suggest that the ovaries removed from ovarian cancer-prone individuals as a preventative measure should be thoroughly examined histologically to identify or rule out microscopic or near-microscopic invasive neoplasms.

Platinum-based chemotherapeutic regimens are ultimately unsuccessful due to intrinsic or acquired drug resistance. Understanding the molecular basis for platinum drug sensitivity/resistance is necessary for the development of new drugs and therapeutic regimens. In an effort to identify such determinants, we evaluated the expression of approximately 4000 genes using cDNA microarray screening in a panel of 14 unrelated human ovarian cancer cell lines derived from patients who were either untreated or treated with platinum-based chemotherapy. These data were analysed relative to the sensitivities of the cells to four platinum drugs (cisdiamminedichloroplatinum (cisplatin), carboplatin, DACH-(oxalato)platinum (II) (oxaliplatin) and cis-diamminedichloro (2-methylpyridine) platinum (II) (AMD473)) as well as the proliferation rate of the cells. Correlation analysis of the microarray data with respect to drug sensitivity and resistance revealed a significant association of Stat1 expression with decreased sensitivity to cisplatin (r ¼ 0.65) and AMD473 (r ¼ 0.76). These results were confirmed by quantitative RT -PCR and Western blot analyses. To study the functional significance of these findings, the full-length Stat1 cDNA was transfected into drug-sensitive A2780 human ovarian cancer cells. The resulting clones that exhibited increased Stat1 expression were three-to five-fold resistant to cisplatin and AMD473 as compared to the parental cells. The effect of inhibiting Jak/Stat signalling on platinum drug sensitivity was investigated using the Janus kinase inhibitor, AG490. Pretreatment of platinum-resistant cells with AG490 resulted in significant increased sensitivity to AMD473, but not to cisplatin or oxaliplatin. Overall, the results indicate that cDNA microarray analysis may be used successfully to identify determinants of drug sensitivity/resistance and future functional studies of other candidate genes from this database may lead to an increased understanding of the drug resistance phenotype.

Horse heart cytochrome c is one of a small number of proteins for which the folding pathway has been elucidated in structural detail by pulsed hydrogen exchange and NMR. Those studies indicated that a partially folded intermediate with interacting N- and C-terminal helices is formed at an early stage of folding when most of the chain is still disordered. This report describes a peptide model for this early intermediate, consisting of a noncovalent complex between a heme-containing N-terminal fragment (residues 1-38) and a synthetic peptide corresponding to the C-terminal helix (residues 87-104). Far-UV circular dichroism and proton NMR indicate that the isolated peptides are largely disordered, but when combined, they form a flexible, yet tightly bound complex with enhanced helical structure. These results emphasize the importance of interactions between marginally stable elements of secondary structure in forming tertiary subdomains in protein folding.

A population pharmacokinetic model for total topotecan has been developed that incorporates measures of body size and renal function to predict total clearance. The model can be used prospectively to obtain a revised and validated model that can then be used to design individualized dosing regimens.