Drought resistance in pearl millet

The influence of wilting on the levels of free proline, soluble proteins, reducing sugars, starch and on the activities of nitrate reductase, invertase, amylase and pyrophosphatases have been studied in the leaf tissue of five cultivars of pearl millet at their vegetative stage under pot culture conditions. The metabolic changes could not be correlated with the yield behaviour of the cultivars under a drought condition in the field.     

Noninvasive Assessment of Tumor VEGF Receptors in Response to Treatment with Pazopanib: A Molecular Imaging Study

Vascular endothelial growth factor (VEGF) and its receptors (VEGFRs) drive angiogenesis, and several VEGFR inhibitors are already approved for use as single agents or in combination with chemotherapy. Although there is a clear benefit with these drugs in a variety of tumors, the clinical response varies markedly among individuals. Therefore, there is a need for an efficient method to identify patients who are likely to respond to antiangiogenic therapy and to monitor its effects over time. We have recently developed a molecular imaging tracer for imaging VEGFRs known as scVEGF/^99mTc; an engineered single-chain (sc) form of VEGF radiolabeled with technetium Tc 99m (^99mTc). After intravenous injection, scVEGF/^99mTc preferentially binds to and is internalized by VEGFRs expressed within tumor vasculature, providing information on prevalence of functionally active receptors. We now report that VEGFR imaging readily detects the effects of pazopanib, a small-molecule tyrosine kinase inhibitor under clinical development, which selectively targets VEGFR, PDGFR, and c-Kit in mice with HT29 tumor xenografts. Immunohistochemical analysis confirmed that the changes in VEGFR imaging reflect a dramatic pazopanib-induced decrease in the number of VEGFR-2⁺/CD31⁺ endothelial cells (ECs) within the tumor vasculature followed by a relative increase in the number of ECs at the tumor edges. We suggest that VEGFR imaging can be used for the identification of patients that are responding to VEGFR-targeted therapies and for guidance in rational design, dosing, and schedules for combination regimens of antiangiogenic treatment.     

Melting characteristics of highly supercoiled DNA

The effect of high supercoil densities on the melting characteristics of a supercoiled DNA has been studied. It is found that although the melting temperature increases abruptly on converting a linear DNA merely into the relaxed circular form, it falls back substantially at high supercoil densities. It is further predicted, in such cases, that the number of melted base pairs should be significantly enhanced even at the physiological temperature, which may facilitate the binding of other molecules to the highly supercoiled DNA.     

Ligand binding isotherm for DNA in the presence of supercoil-induced non-B form: a theoretical analysis

A binding isotherm in the form of a modified McGhee-Von Hippel equation is proposed, on the basis of thermodynamical considerations, to include the non-cooperative binding of extended ligands to supercoiled DNA, where a stretch of non-B form may be present under superhelical stress. It is then studied, on the basis of a non-linear Scatchard plot, how the presence of an intercalating ligand can relax the supercoiled molecule and thus destabilise the non-B stretch, which may be recognised by the existence of a significant kink in the Scatchard plot.     

Removal of endotoxin from antibody preparations for clinical use

Cell Biochemistry and Biophysics - Despite attempts to maintain asepsis, good manufacturing practices, and the use of terminal sterilization by millipore filtration, the nuclear practitioner is...     

Effects of dopamine on chemoreflexes in breathing

The effects of intravenous infusion of dopamine (20 microgram.min) on the steady-state ventilatory and carotid chemoreceptor responses to successive levels of isocapnic hypoxia and hyperoxic hypercapnia were investigated in cats anesthetized with alpha-chloralose. Dopamine infusion was followed by a maximal decrease in ventilation in about 20 s. Thereafter, the effect diminished and stabilized. Termination of dopamine infusion was promptly followed by an increase in ventilation. These ventilatory responses were smaller than the corresponding carotid chemoreceptor responses. The steady-state effect of dopamine infusion was to diminish ventilation at all levels of arterial O2 tension, the decrease being greater during hypoxia than that during hyperoxia. Bilateral section of the carotid sinus nerves significantly diminished but did not abolish the inhibitory effect of dopamine on ventilation during hyperoxia. Thus the ventilatory depression due to dopamine infusion is not entirely due to its effect on the carotid chemoreceptors. Dopamine decreased ventilatory responses to successive levels of hypercapnia by the same magnitude without changing the slope of the response curves. The steady-state relationship between chemoreceptor activity and ventilation shows that the ventilatory equivalent for carotid chemoreceptor activity is increased during dopamine infusion because of its greater inhibitory effect on carotid chemoreceptor activity than on ventilation with the decrease of arterial O2 tension.