Cytotoxic activity of extracts from Hypochaeris radicata.

Pasture-associated stringhalt is an acquired equine disease characterized by peripheral neuropathy and hyperflexion of the pelvic limbs. The disease occurs most commonly during periods of drought in horses grazing pastures heavily contaminated by Hypochaeris radicata. We hypothesized that stringhalt is caused by neurotoxins elaborated by H. radicata in response to the stress of drought conditions. Supernates were collected from H. radicata that were stressed (or not) by immersion in copper chloride solution, then extracted with ethyl acetate and dried. Dilutions of extracts from stressed (SE) and control, unstressed (UE) plants were incubated with myelinating spinal cord cultures (MSCC) established from fetal Swiss mice, and with spinal ganglion cultures (SGC) and dermal fibroblast cultures derived from neonatal mouse tissues. Cytotoxicity in culture monolayers was evaluated both morphologically by microscopy and by release of lactate dehydrogenase activity into culture supernates. Three different SGC preparations were exposed to a single H. radicata extract and single preparations of fibroblasts and MSCC were exposed to three different extracts. Repin, a plant-derived sesquiterpene lactone neurotoxin, was included as a positive control. Significant dose-dependent cytotoxicity was seen within 24 h in all three culture types when incubated with SE or repin. Complete morphologic destruction of culture monolayers was induced by the highest concentrations tested of SE (100 µg/mL) and repin (30 µg/mL). Cytotoxic effect of SE was significantly greater than that of UE for all three cell types and was not due to copper contamination of the extract. This study has identified a cytotoxic activity in leaf exudates of H. radicata that was upregulated by the model stressor, copper chloride.

The challenge of evaluating a child bereavement programme.

This paper will discuss the challenge of evaluating the efficacy of child bereavement services. Such services are being developed and it is essential that expansion is based on research and evaluation. A literature review details the limited research which has so far been conducted on such interventions. The paper then addresses four key components regarding child bereavement programme evaluation: preliminary evaluation of the Winston's Wish programme; the feasibility and validity of using an experimental method in the evaluation of child bereavement services; the identification of appropriate measures-what are we really attempting to measure with regard to child bereavement interventions; and the importance of measuring the family dynamics of grief-how can we incorporate the Dual Process Model?

Synthesis and in vitro and in vivo antitumor activity of a series of trans platinum antitumor complexes.

The synthesis of a series of platinum complexes of trans coordination geometry [centered around the general formula, trans-ammine(amine)dichlorodihydroxoplatinum(IV) plus corresponding tetrachloroplatinum(IV) or Pt(II) counterparts] is described as part of a drug discovery program to identify more effective platinum-based anticancer drugs, particularly targeted toward the circumvention of resistance to cisplatin. Complexes have been evaluated for antitumor activity using in vitro and in vivo tumor models. In vitro against a panel of cisplatin-sensitive and -resistant human tumor cell lines (predominantly ovarian), many of the trans platinum complexes studied (e.g., 1, R = cyclohexyl) exhibited comparable potency to cisplatin and also overcame acquired cisplatin resistance, where resistance was due mainly to either reduced drug uptake or enhanced platinum-DNA adduct removal. Moreover, 14 trans complexes showed significant in vivo antitumor activity against the subcutaneous murine ADJ/PC6 plasmacytoma model; all were platinum(IV) complexes, 13/14 possessing axial hydroxo ligands the other possessing axial ethylcarbamato ligands. Where tested, all of their respective platinum(II) or tetrachloroplatinum(IV) counterparts were inactive. Notably, three dihydroxoPt(IV) complexes (18, 29, 34) (R = c-hexyl, c-heptyl, and 1-adamantyl) retained some efficacy against a cisplatin-resistant variant of the ADJ/PC6. Compounds 18 (trans-[PtCl2(OH)2NH3-(RNH2)]) R = c-C6H11, 22, R = Me3C, 27, R = n-C6H13, 28, R = PhCH2, and 36 (trans-[PtBr2(OH)2NH3(c-C6H11NH2)]) also produced evidence of antitumor activity (> 5 days growth delay) against subcutaneously grown advanced stage human ovarian carcinoma xenografts. These data demonstrate that a series of trans-ammine(amine)dichlorodihydroxoplatinum(IV) complexes are active in vivo against both murine and human subcutaneous tumor models and represent potential leads to a new generation of platinum-based anticancer drug.