The role of structural factors in the kinetics of cellular uptake of pyrazoloacridines and pyrazolopyrimidoacridines: implications for overcoming multidrug resistance towards leukaemia K562/DOX cells

The appearance of multidrug resistance (MDR) of tumour cells to a wide array of antitumour drugs, structurally diverse and having different mechanisms of action, constitutes the major obstacle to the successful treatment of cancer. Our approach to search for non-cross resistant antitumour agents is based on the rational design of derivatives, which have a high kinetics of passive cellular uptake rendering their active efflux by MDR exporting pumps inefficient. Recently, two families of acridine cytotoxic agents were obtained, pyrazoloacridines (PACs) and pyrazolopyrimidoacridines (PPACs). The aim of this study was to examine molecular basis of the reported differences in retaining cytotoxic activity of these derivatives at cellular level against resistant erythroleukaemia K562/DOX (overexpressing P-glycoprotein) cell line. The study was performed using a spectrofluorometric method, which allows continuous monitoring of the uptake and efflux of fluorescent molecules by living cells. It was demonstrated that the presence of two additional rings, pyrazole and pyrimidine, fused to the acridine chromophore structure (PPAC) favoured more rapid cellular diffusion than the presence of only one additional pyrazole ring (PAC). The presence of hydrophobic substituent OCH3 markedly favoured the cellular uptake of pyrazoloacridines and pyrazolopyrimidoacridines while compounds having hydrophilic substituent OH exhibited very low kinetics of cellular uptake. In contrast, it was found that neither structure of the ring system nor the hydrophobic/hydrophilic character of examined substituents determined the rate of active efflux of these compounds by P-glycoprotein. Our data showed that a nearly linear relation exists between the resistance factor (RF) and lnV+ reflecting the impact of the cellular uptake rate (V+) on the ability of these compounds to overcome MDR.     

Oxcarbazepine pharmacokinetics and tolerability in children with inadequately controlled epilepsy

This two-part, open-label study evaluated the pharmacokinetics, safety, and tolerability of oxcarbazepine as combination therapy in 112 children 2 to 12 years old with inadequately controlled epilepsy. Part I was a pharmacokinetic study in children stratified by age (2-5 years and 6-12 years) and randomized to receive a single oxcarbazepine dose of 5 mg/kg or 15 mg/kg. Mean specific AUC and t(1/2) values of the active metabolite (MHD) were approximately 30% lower in younger children compared with older children, regardless of dose. Part II was a 4-month safety, tolerability, and pharmacokinetic study in which children received oxcarbazepine doses of 11 to 68 mg/kg/day. The mean specific oxcarbazepine daily dose was 38% higher in younger children compared with older children. Similarly, mean trough plasma MHD concentrations were 34% lower in younger children. Six (5%) children discontinued due to adverse events. Oxcarbazepine was safe and well tolerated. Younger children require higher oxcarbazepine doses because of rapid clearance.     

Biomaterial challenges and approaches to stem cell use in bone reconstructive surgery

As life expectancy increases, so does the need to treat large bone defects. New biomaterials combined with osteogenic cells are now being developed as an alternative to autogenous bone grafts. The goal is to make the stem cells adhere to the scaffold, and then grow to differentiate into functional osteogenic cells and organize into healthy bone as the scaffold degrades. Decisive improvements have been made in the fields of stem cell biology, 3-D scaffold fabrication and tissue engineering, but the ideal bone substitute that fulfils all functional and safety requirements has yet to be developed.     

BI-32169, a bicyclic 19-peptide with strong glucagon receptor antagonist activity from Streptomyces sp

A new bicyclic 19-peptide, BI-32169, has been isolated from the culture broth of Streptomyces sp. (DSM 14996). Its structure has been established by amino acid analysis, mass spectrometry, and 2D NMR analysis. BI-32169 consists exclusively of protein amino acids and is cyclized from the side chain of Asp(9) to the N-terminus of Gly(1). One disulfide bond between Cys(6) and Cys(19) forms a bicyclic structure. BI-32169 and its methyl ester derivative showed potent inhibitory activity against the human glucagon receptor (IC(50) 440 and 320 nM, respectively) in a functional cell-based assay.     

Clinical outcome of prophylactic oophorectomy in BRCA1/BRCA2 mutation carriers and events during follow-up

A retrospective study was performed to assess the histopathologic findings in high-risk women undergoing bilateral prophylactic (salpingo)-oophorectomy. The medical files of BRCA1 or BRCA2 mutation carriers and members of a hereditary breast/ovarian cancer (HBOC) family, who had undergone prophylactic surgery, were reviewed. In all, 38 women underwent a bilateral oophorectomy (26 BRCA1, three BRCA2 and nine HBOC, respectively). A total of 90 women underwent bilateral salpingo-oophorectomy (58 BRCA1, six BRCA2, one BRCA1 and 2, 25 HBOC, respectively). At the time of salpingo-oophorectomy, five of 58 BRCA1 carriers (8.6%) were diagnosed with an occult carcinoma: two fallopian tube carcinomas, two ovarian carcinomas and one case was defined as a fallopian tube/ovarian carcinoma. No occult carcinomas were found in the other groups. Of the 38 patients, who underwent a bilateral oophorectomy (mean follow-up 45 months), three of 26 BRCA1 mutation carriers (3.4 in 100 women-years) developed peritoneal papillary serous carcinoma (PPSC) during follow-up. So far, no PPSC have occurred in the 90 women, who underwent a salpingo-oophorectomy (mean follow-up 12 months), including 58 BRCA1 carriers (0 in 60 in women-years). These results contribute to the thesis that BRCA1 germline mutation carriers are not only at risk for ovarian cancer, but also for fallopian tube carcinoma and peritoneal papillary serous carcinoma. Our data suggest that PPSC risk among BRCA2 carriers is lower than among BRCA1 carriers.     

Radiation dose, chemotherapy and risk of soft tissue sarcoma after solid tumours during childhood

Soft tissue sarcoma (STS) is one of the most frequent second primary cancer that occurs during the first 20 years following treatment for a solid cancer in childhood. Our aim was to quantify the risk of STS as a second malignant neoplasm and to investigate its relationship with radiotherapy and chemotherapy. A cohort study of 4,400 3-year survivors of a first solid cancer diagnosed during childhood in France or the United Kingdom, between 1942 and 1985, was followed 15 years on average. In a partially nested case-control study, we matched 25 cases of STS and 121 controls for sex, type of first cancer, age at first cancer and duration of follow-up. Sixteen STS occurred in the cohort, as compared to 0.3 expected from the general population (Standardized Incidence Radio, SIR = 54 (95%CI: 34-89)). The SIR was 113 (95% CI: 62-185) after chemotherapy plus radiotherapy (13 STS), whereas it was 28 (95%CI: 2-125) after chemotherapy alone (1 STS) and 19 (95%CI: 3-60) after radiotherapy alone (2 STS). After adjustment for treatment, there was no evidence of variation in the annual excess of incidence or in the SIR with either age at first cancer or time since 1st cancer. In the case-control study, the risk of a STS was increased with the square of the dose of radiation to the site of STS development and with the administration of Procarbazine. The increased risk of soft tissue sarcoma that occurred after childhood cancer is independently related to exposure to radiotherapy and Procarbazine. A closer surveillance of children treated with this treatment combination is strongly recommended.     

Contralateral axillary sentinel lymph node drainage in breast cancer: a case report

BACKGROUND: Since the introduction of sentinel node (SN) mapping in breast cancer, extra-axillary lymph node sites of breast tumor drainage are discovered in about one-quarter of cases, especially after intraparenchymal injection. In most such cases, an ipsilateral axillary SN is associated with an extra-axillary SN. Non visualization of ipsilateral axillary SN and extra-axillary SN drainage are often associated with an increased risk of axillary involvement. CASE: We report a case of contralateral axillary SN drainage on lymphoscintigraphy in a breast cancer patient with a history of bilateral reduction mammoplasty and no ipsilateral axillary lymph node involvement.