Safety profile of Hoodia gordonii extract: mouse prenatal developmental toxicity study.

Hoodia gordonii extract (0, 5, 15 or 50mg/kg body weight/day, n=24 mice/group) was orally administered by gavage to female CD-1 mice from gestation days 5-17. On gestation day 18 the females were euthanized and examined. Treatment at 50mg/kg/day caused a marked reduction in feed intake and body weight gain. Feed consumption was sporadically reduced at 15 mg/kg/day. At 50 or 15 mg/kg/day fetal weights, ossification of some bones and full and empty uterus weights were reduced. There were no clear maternal or fetal effects at 5mg/kg/day. Reproductive indices were unaffected at all doses and there were no treatment-related malformations, anomalies or variations. The overall study no-observed-adverse-effect level was set at 5mg/kg/day. In summary, at doses that reduced maternal feed consumption, H. gordonii extract delayed fetal development. The fetal effects seen could be consequent to reduced maternal feed consumption, the desired biological activity of the test item.

Safety profile of Hoodia gordonii extract: rabbit prenatal developmental toxicity study.

Hoodia gordonii extract was orally administered by gavage to groups of 22 female New Zealand white rabbits from day 3-28 after mating at doses of 0 (control), 3, 6 or 12 mg/kg bodyweight/day. These doses were reached by a dose escalation phase between days 3 and 7 after mating. As well as a vehicle control group, a control group pair-fed to the high dose was also included. On day 29 after mating the females were euthanized and examined. Treatment at 6 or 12 mg/kg/day was associated with a dose-related reduction in feed intake and bodyweight gain. Feed consumption and bodyweight gain was unaffected at 3mg/kg/day. In spite of marked maternal effects at 12 mg/kg/day, reproductive indices were unaffected at all doses and there were no effects on fetal or placental weights and no morphological changes in the fetuses. The no-observed-effect level (NOEL) for developmental effects was therefore 12 mg/kg/day, and the maternal NOEL was 3mg/kg/day. At doses that caused marked maternal effects, H. gordonii extract did not affect embryonic or fetal development in a species that is considered predictive of developmental toxicity in man.

Chemical characterisation of Hoodia gordonii extract.

The chemical composition of a solvent extract of Hoodia gordonii termed 'H.gordonii extract' has been characterised by hyphenated chromatographic methods and traditional analytical techniques. The extract consists of a mixture of steroid glycosides, fatty acids, plant sterols and polar organic material. High performance liquid chromatography (HPLC) with ultra violet (UV) and mass spectrometric (MS) detection was used to quantify and confirm the identity of a number of steroid glycosides (73.7% w/w) present in the extract. Gas chromatography (GC) with MS and flame ionisation detection (FID) was applied to determine the fatty acid (3.12% w/w) sterol (0.39% w/w) and alcohol (0.03% w/w) content of a saponified sample of the extract. Polar organic material was quantified by gravimetric methodology using C(18) SPE separation and was determined to be a minimum of 3% w/w. Moisture content was measured by Karl Fischer coulometric titration (0.81% w/w). The protein content was investigated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) with SYPRO Ruby staining and a negative result was determined with a limit of detection of <0.001%w/w of protein per band. The chemical composition of the extract remained stable for 19 months when stored in re-sealable plastic bags at ambient (21-24°C) temperature and <60% relative humidity.

Preclinical evaluation of a prostate-targeted gene-directed enzyme prodrug therapy delivered by ovine atadenovirus.

Gene-directed enzyme prodrug therapy (GDEPT) based on the Escherichia coli enzyme, purine nucleoside phosphorylase (PNP), provides a novel strategy for treating slowly growing tumors like prostate cancer (CaP). PNP converts systemically administered prodrug, fludarabine phosphate, to a toxic metabolite, 2-fluoroadenine, that kills PNP-expressing and nearby cells by inhibiting DNA, RNA and protein synthesis. Reporter gene expression directed by a hybrid prostate-directed promoter and enhancer, PSMEPb, was assayed after plasmid transfection or viral transduction of prostate and non-CaP cell lines. Androgen-sensitive (AS) LNCaP-LN3 and androgen-independent (AI) PC3 human CaP xenografts in nude mice were injected intratumorally with an ovine atadenovirus vector, OAdV623, that carries the PNP gene under PSMEPb, formulated with cationic lipid for enhanced infectivity. Fludarabine phosphate was then given intraperitoneally for 5 days at 75 mg/m2/day. PNP expression was evaluated by enzymic conversion of its substrate using reverse phase HPLC. OAdV623 showed excellent in vitro transcriptional specificity for CaP cells. In vivo, expression of PNP persisted for > 6 days after OAdV623 injection and a single treatment provided 100% increase in tumor doubling time and > 50% inhibition of tumor growth for both LNCaP-LN3 and PC3 lines, with increased tumor necrosis and apoptosis and decreased tumor cell proliferation. OAdV623 significantly suppressed the growth of AS and AI human CaP xenografts in mice.

Conditioned suppression of behavior maintained by intracranial stimulation as a function of stimulation intensity.

Conditioned suppression was demonstrated in two experiments with rats lever pressing on a fixed-ration 1 schedule for lateral hypothalamic intracranaial stimulation (ICS)'n Experiment I, conditioned suppression of responding for low-intensity ICS was obtained with a moderate intensity of foot shock, In Experiment II, low and high intensities of ICS were alternated within the same session and the same animal The suppression that was exhibited with low intensity ICS was minimal or absent with high-intensity stimulation, despite the pairing of foot shock with each warning stimulus. Conditioned suppression was a function of ICS intensity, and was independent of response rates. The inverse relationship between ICS intensity and degree os suppression is consistent with a motivational analysis of conditioned suppression. Previous reports of resistance to suppression of behaviors maintained by ICS may now be attributed to the use of high-intensity stimulation.