PrestoBlue® and AlamarBlue® are equally useful as agents to determine the viability of Acanthamoeba trophozoites.

Acanthamoeba is an opportunistic pathogen which is the causal agent of several human infections such as Granulomatous Amoebic Encephalitis, Acanthamoeba keratitis and other disseminated infections. Furthermore, current therapeutic measures against Acanthamoeba infections are arduous, and show limited efficacy against the cyst stage of Acanthamoeba. There is a pressing need to search and evaluate new therapeutic agents against these protozoa. Our approach for evaluating possible new drugs is an initial in vitro screening assay based on general metabolic activity of the cells. In this study we compare two agents, AlamarBlue® and PrestoBlue® for this initial screen. Both reagents can be used to indicate metabolism by changes in their absorbance or fluorescence. The assay is carried out in a 96-well plate format and fluorescence can be measured after an inoculation period of as little as 10 min, but more typically 96 h. This to the best of our knowledge this is the first time that both compounds are directly compared using absorbance and fluorescence measurement. We conclude that for the specific case of Acanthamoeba both agents AlamarBlue® and PrestoBlue® are equally useful to determine cell viability.

Field evaluation of reduced insecticide spray programs for managing plum curculio, Conotrachelus nenuphar (Coleoptera: Curculionidae), in Alabama peaches.

BACKGROUND: Plum curculio (PC), Conotrachelus nenuphar (Herbst.), is an important pest of peaches in the southeastern United States. Commercially acceptable control of this insect is typically achieved by weekly or biweekly application of broad-spectrum conventional insecticides, resulting in 6-12 sprays per season. Experiments were conducted in a peach orchard in Alabama during 2007-2009 to compare the conventional calendar-based insecticide spray program involving weekly applications of phosmet with three different reduced spray programs using three targeted (well-timed) insecticide sprays (TIS) of phosmet, permethrin or thiamethoxam applied in an alternated fashion. RESULTS: All three TIS programs significantly reduced PC damage at harvest compared with the untreated control in two of the three years (2008 and 2009). Fruit damage due to stink bugs, which are emerging pests of peaches in the region, was also significantly reduced in the TIS programs in both years. In a separate trial in which one of the TIS programs (three targeted sprays of phosmet) was evaluated in a larger peach block in 2009, percentage fruit damage due to PC increased from < 1% in June to ~4% in late July. CONCLUSION: All the TIS programs evaluated provided effective control of PC and represent potential alternatives to the conventional weekly spray program in peaches with concomitant reduction in insecticide usage and associated costs. However, an additional spray may be necessary for effective control of PC and stink bugs in late-season peach varieties.

Didanosine, lamivudine-emtricitabine and efavirenz as initial therapy in naive patients.

There are currently several suitable and different antiretroviral regimens to start highly active antiretroviral therapy (HAART), and many clinicians and patients prefer once-daily therapy. The efficacy and potency of efavirenz (EFV) has been established in many clinical trials and cohort studies; its pharmacokinetics, allowing for a convenient once-daily administration, make EFV one of the first agents to be included in once-daily regimens in naive patients. The two nucleoside reverse transcriptase inhibitors (NRTIs) accompanying the third drug have become the central skeleton, or the 'backbone' of the therapeutic scheme. Among the different NRTI pairs, a didanosine-lamivudine (3TC) or emtricitabine backbone for combination antiretroviral therapy may be a good option compared with any current NRTI-combinations due to its security, tolerance and once-daily dose. In this article, we review the advantages and drawbacks of didanosine-XTC-EFV as the initial regimen of HAART in HIV-infected patients.

High-performance liquid chromatographic method for the determination of HIV-1 non-nucleoside reverse transcriptase inhibitor efavirenz in plasma of patients during highly active antiretroviral therapy.

A new high-performance liquid chromatographic method for the determination of efavirenz in human plasma is described. Quantitative recovery following liquid-liquid extraction with diethylether from 200 microl of human plasma was achieved. Subsequently, the assay was performed with 67 mM potassium dihydrogen phosphate-acetonitrile as a mobile phase, a XTerraRP 18 column protected with a Phenomenex C18 column and UV detection at 246 nm. Linear standard curves were obtained for concentrations ranging from 25 to 15,000 ng/ml. The calculated intra- and inter-day coefficients of variation were below 10%.

Crystallization of beta-galactosidase does not reduce the range of activity of individual molecules.

By use of a capillary electrophoresis-based procedure, it is possible to measure the activity of individual molecules of beta-galactosidase. Molecules from the crystallized enzyme as well as the original enzyme preparation used to grow the crystals both displayed a range of activity of 20-fold or greater. beta-Galactosidase molecules obtained from two different crystals had indistinguishable activity distributions of 31,600 +/- 1100 and 31,800 +/- 1100 reactions min(-1) (enzyme molecule)(-1). This activity was found to be significantly different from that of the enzyme used to grow the crystals, which showed an activity distribution of 38,500 +/- 900 reactions min(-1) (enzyme molecule)(-1).