Synthesis of a stable and orally bioavailable englerin analogue.

Synthesis of analogues of englerin A with a reduced propensity for hydrolysis of the glycolate moiety led to a compound which possessed the renal cancer cell selectivity of the parent and was orally bioavailable in mice.

Early treatment with prednisolone or acyclovir in Bell's palsy.

BACKGROUND: Corticosteroids and antiviral agents are widely used to treat the early stages of idiopathic facial paralysis (i.e., Bell's palsy), but their effectiveness is uncertain. METHODS: We conducted a double-blind, placebo-controlled, randomized, factorial trial involving patients with Bell's palsy who were recruited within 72 hours after the onset of symptoms. Patients were randomly assigned to receive 10 days of treatment with prednisolone, acyclovir, both agents, or placebo. The primary outcome was recovery of facial function, as rated on the House-Brackmann scale. Secondary outcomes included quality of life, appearance, and pain. RESULTS: Final outcomes were assessed for 496 of 551 patients who underwent randomization. At 3 months, the proportions of patients who had recovered facial function were 83.0% in the prednisolone group as compared with 63.6% among patients who did not receive prednisolone (P<0.001) and 71.2% in the acyclovir group as compared with 75.7% among patients who did not receive acyclovir (adjusted P=0.50). After 9 months, these proportions were 94.4% for prednisolone and 81.6% for no prednisolone (P<0.001) and 85.4% for acyclovir and 90.8% for no acyclovir (adjusted P=0.10). For patients treated with both drugs, the proportions were 79.7% at 3 months (P<0.001) and 92.7% at 9 months (P<0.001). There were no clinically significant differences between the treatment groups in secondary outcomes. There were no serious adverse events in any group. CONCLUSIONS: In patients with Bell's palsy, early treatment with prednisolone significantly improves the chances of complete recovery at 3 and 9 months. There is no evidence of a benefit of acyclovir given alone or an additional benefit of acyclovir in combination with prednisolone. (Current Controlled Trials number, ISRCTN71548196 [controlled-trials.com].).

Receptor dependent cellular uptake of synthetic low density lipoprotein by mammalian cells in serum-free tissue culture.

Low density lipoprotein (LDL) is a normal plasma component, which is of interest in a number of research areas such as hypercholesterolaemia, drug targeting in cancer chemotherapy and as a lipid supplement in tissue culture systems. Currently, however, it can only be obtained by extraction from fresh plasma samples, which yields only small quantities. Synthetic LDL (sLDL) has been prepared using readily available lipid components coupled with a synthetic amphiphatic peptide molecule containing the apoprotein B receptor sequence. sLDL was capable of supporting the growth of Chinese Hamster Ovary (CHO) and fibroblast cells in serum-free culture media in a cholesterol-dependent manner that was related to the presence of the receptor peptide molecule. sLDL could be fluorescently labelled with 3,3'-dioctadecyloxalocarbocyanine perchlorate (DiO), and once labelled was assimilated by CHO and fibroblast cells in a time- and temperature-dependent manner that was dependent upon the presence of the receptor peptide. In addition, assimilation was reduced by an excess of unlabelled native LDL. The results indicated that the interaction of sLDL with CHO and fibroblast cells occurred via a receptor dependent system, most likely the LDL cellular receptor. sLDL is therefore a useful, easily obtained substitute for native LDL with potential applications in the areas of drug targeting to cells and serum-free tissue culture systems.

Synthetic low-density lipoprotein, a novel biomimetic lipid supplement for serum-free tissue culture.

Lipid supplementation in serum-free tissue culture employs solubilization techniques to permit the addition of lipids, but these systems are potentially cytotoxic and do not present lipid in a natural form. In this research a simplified preparation method for synthetic low-density lipoprotein (sLDL) has been developed that involves microfluidization of a solvent lipid solution in a simple aqueous solution. This produces material with size and zeta potential characteristics similar to those of native LDL. sLDL supplementation in tissue culture media provides cholesterol concentrations higher than those achieved by 10% serum supplementation and existing chemically defined lipid supplements. sLDL stimulates NS0 and U937 cellular proliferation in completely serum-free media, the former in a lipid concentration dependent manner that is also related to both the receptor peptide structure employed and its concentration on the particle. The greatest NS0 cellular proliferation was obtained at the highest cholesterol concentration tested (0.5 mg/mL), which was 10 times higher than the cholesterol concentration achieved by standard 10% serum supplementation. U937 cellular proliferation was influenced by variation of sLDL's fatty acid constituents with a natural mixture producing maximal effect. Cell uptake studies in NS0 with fluorescently labeled sLDL indicated that assimilation is reduced by competition from native LDL. The planktonic nature of NS0 cell growth meant that cell binding and uptake experiments were difficult to conduct because of cellular aggregation. However, sLDL-induced U937 proliferation is ablated by the presence of an anti-LDL receptor antibody. The results indicate that sLDL uptake is via the LDL receptor and that sLDL can function as a lipid supplement for serum-free media capable of supplementation to cholesterol concentrations up to 0.5 mg/mL. Cellular uptake studies also suggest that sLDL will be useful for the targeting and delivery of materials to cells. sLDL therefore represents a new and promising synthetic biomimetic alternative to native LDL with multiple applications.