Sensitivity of the nested-polymerase chain reaction (PCR) assay for Brugia malayi and significance of 'free' DNA in PCR-based assays.

The blood filtration method was used as the gold standard to determine the detection level of simple blood-spot sampling and nested-polymerase chain reaction (PCR) for Brugia malayi. Of 100 samples, 48 were filtration-positive. Of these, 26 had microfilaria counts that were low enough (<1-29 microfilariae/ml) to accurately assess the limit of detection by nested-PCR.

Simple blood-spot sampling with nested polymerase chain reaction detection for epidemiology studies on Brugia malayi.

In the absence of a suitable Brugia malayi antigen detection assay, PCR remains one of the more sensitive alternatives to Giemsa-stained thick blood films for B. malayi detection. The need for refrigerated storage and transportation of blood has limited the use of PCR for large-scale epidemiology studies in remote endemic areas.

Evidence for a symmetrical requirement for Rab5-GTP in in vitro endosome-endosome fusion.

Early endosome fusion, which has been extensively characterized using an in vitro reconstitution assay, is Rab5-dependent. To examine the requirement for Rab5 on both fusion partners, we prepared cytosol and endosomes depleted of Rab5. Unlike control cytosol, Rab5-depleted cytosol was only marginally active in the in vitro endosome fusion.

In vitro selective glycogen depletion of frog twitch and slow muscle fibres.

Glycogen as measured histochemically with periodic acid-Schiff (PAS) reaction was depleted in frog muscle fibres following electrical stimulation of the nerve. The types of the muscle fibres examined were identified in serial cryostat sections. We used appropriate stimulation regimes which provide a heavy work load only for twitch fibres (at low stimulation frequency) or selectively for slow fibres (contractures in response to high frequency stimulation or pharmacological agents).