Type L pyruvate kinase from mouse liver has been studied. The enzyme is strongly inhibited by low concentrations of copper ions, and the inhibition is reversed by fructose 1,6diphosphate. In the absence of inhibitor, fructose 1,6diphosphate also increases the pyruvate kinase activity at pH values higher than 7. Furthermore, the Cu++ inhibition is pH and K+ concentration dependent. Plots of reac...

A new atropine drug-FET sensor, which was made of an ISFET (ion sensitive field effect transistor) and a drug sensitive membrane prepared by adding electric active matter to a β-cyclodextrin solution, was developed. The pH influence, selectivity, response curve, reproducibility, stability, response time and life of this sensor were investigated. A preliminary application of the sensor was discu...

The effects of 1-naphthaleneacetic acid (NAA) and other auxin analogs on the transmembrane potential difference (Em) were compared on tobacco protoplasts isolated from two genotypes differing in their sensitivity to auxins. For both types, NAA modifies Em by inducing at low doses a hyperpolarization, the amplitude of which increased with auxin concentration. Above an optimal concentration this ...

After Fundulus heteroclitus have been for some time in the laboratory, under conditions favorable for growth, and after habituation of the fishes to the simple routine manipulations of the observational procedure required, they are found to give reproducible values of the mean critical flash illumination (I(m)) resulting in response to visual flicker. The measurements were made with equality of...

Methoprene is a growth-regulating insecticide that manifests its toxicity to target organisms by acting as a juvenile hormone agonist. Methoprene similarly may exert toxicity to crustaceans by mimicking or interfering with methyl farnesoate, a crustacean juvenoid. We hypothesized that methoprene interferes with endocrine-regulated processes in crustaceans by several mechanisms involving agonism...

Patients with plasma viral RNA >50,000 copies/mL, despite a protease-inhibitor regimen, received abacavir, amprenavir, and efavirenz to assess efavirenz-amprenavir drug interactions and to evaluate safety and antiviral response. Patients first received amprenavir with abacavir and other nucleoside analogs. Amprenavir levels were measured before and after adding efavirenz. Patients then received...

Cell line cytotoxicity assays have become increasingly popular approaches for genetic and genomic studies of differential cytotoxic response. There are an increasing number of success stories, but relatively little evaluation of the statistical approaches used in such studies. In the vast majority of these studies, concentration response is summarized using curve-fitting approaches, and then su...

A 6-hour application (6-hour pulse) of 1 millimolar azide significantly changed the phase of the potassium uptake rhythm of Lemna gibba G3. The phase response curve obtained was type 0 and very similar to that caused by a 6-hour pulse of low temperature (5 degrees C) or darkness. The magnitude of the phase shift and the type of the phase response curve depended on the concentration of azide. Ho...

Two simple, precise and economical UV spectrophotometric methods have been developed for the estimation of Hydroxychloroquine in pharmaceutical dosage form. Method A applied was area under curve (AUC) in which area under curve was integrated in the wavelength range of 251-261nm using water as a solvent. Method B involves getting first order derivative spectrum of drug solution and measurement o...

Background: The prevalence of genetically determined lactase non-persistence is based on the results of the lactose H 2 breath test. This test, however, is an indirect test, which might lead to misinterpretation. Design: We determined lactase activity in healthy Chinese and Dutch students using a novel C-lactose digestion test. The cut-off value of this test was established in a Chinese populat...