The Effects of L(+), D(-), and DL-2-amino-4-phosphonobutyrate (APB) on Electroretinogram and Ganglopn Cell Activity in the Cat Retina

L(+)-, D(-)-, or DL-2-amino-4-phosphonobutyric acid (APB; 2.5- 16 μmol) were injected into the vitreous body of anesthetized adult cats. The retina was stimulated by diffuse square wave light flashes (10- 60 ms). The flash-induced electroretinogram (ERU) and responses of single retinal ganglion cells (RGC) were recorded simultaneously. Intravitreal injection of L(+)APB led to a decrease in the ERG b-wave amplitude and the unmasking of the a-wave. The magnitude and rate of the b-wave reduction were different for the two enantiomers. The threshold dose of D(-)APB was 6 times higher than for L(+)APB. L(+)APB (8.2 ± 1.6 μmol; n=7) decreased the b-wave with an average time constant r = 88.5 min, D(-)APB (13.2 ± 1.1 μmol; n=6) with r = 357.1 min, and DL-APB (8.35 ± 1.1 μmol; n=5) with r = 101.0 min. Concomitant with the reduction of the b-wave, L(+)APB (2.7μmol) inhibited both the spontaneous and light-evoked firing in ON-center ganglion cells. The threshold doses of L(+), D(-) and DL-APB for inhibition of spontaneous adivity and the light response in ON-center cells paralleled those in reducing the ERU h-wave. Low doses of L(+)APB or DL-APB that were effective in blockng ON-center cell activity caused only very small changes in the activity of OFF-center ganglion cells. However, high doses of L(+)APB (≥8.2μmol) or DL-APB (≥13.7 μmol) also decreased the spontaneous and light-evoked activity in OFF-center RGC and first shortened than prolonged the light-induced inhibition of OFF-center RGC.Whitehall Foundation (S93-24

Stroke therapy in traditional Chinese medicine (TCM): prospects for drug discovery and development.

Brain injuries resulting from stroke are a major and increasing public health problem in both developed and developing countries worldwide. China's extensive experience in the use of traditional Chinese medicines (TCMs) in stroke therapy indicates that TCM preparations are effective, with few or no side-effects. There are more than 100 traditional medicines in use for stroke therapy in China. Some of their therapeutic effects in stroke have been confirmed by recent clinical studies. A large number of compounds have been isolated from TCMs and most of these resources have not yet been characterized for pharmacological purposes. Here, this article explains how TCM provides an extensive and knowledge-rich foundation for implementing a strategically focused pharmacological research program aimed at the development of new drugs

Preservation of DNA and protein biofunctionality for bio-MEMS & NEMS fabrication

2006 NSTI Nanotechnology Conference and Trade Show - NSTI Nanotech 2006 Technical Proceedings2294-29

Preservation of DNA and protein biofunctionality for bio-MEMS & NEMS fabrication

2006 NSTI Nanotechnology Conference and Trade Show - NSTI Nanotech 2006 Technical Proceedings2294-29

A non-muscle myosin II motor links NR1 to retrograde trafficking and proteasomal degradation in PC12 cells

10.1016/j.neuint.2009.12.020Neurochemistry International564569-57

Neuroprotective versus neurodestructive effects of NO-related species

Nitric oxide (NO·) can lead to damaging or protective actions in the central nervous system. Here we consider the chemistry of the NO group and its redox-related species that can lead to these exactly opposite ends. In the neurodestructive mode, NO· reacts with superoxide anion (O₂·^-) to form peroxynitrite (ONOO^-), which leads to neuronal injury. In contrast, the reaction of the NO group with cysteine sulfhydryls on the NMDA receptor leads to a decrease in receptor/channel activity, avoidance of excessive Ca²⁺ entry, and thus neuroprotection. Site-directed mutagenesis of recombinant NMDA receptor subunits has recently increased our knowledge of such redox modulation by NO. Transfer of the NO group to cysteine sulfhydryls on the NMDA receptor or other proteins, known as S-nitrosylation, is becoming recognized as a ubiquitous regulatory reaction, akin to phosphorylation, and represents a form of redox modulation in diverse tissues including the brain

Micro flow patterns on demand using surface-chemistry technology

A new technology to pattern surface charges, either negatively or positively, using a standard photolithography process is introduced. Unlimited flow patterns can be generated under an externally applied electric field by electro-osmotic and electrophoretic driving forces to enable fine control of fluid motion in microfluidic devices. Two basic flows, shear and vortical, have been realized experimentally to demonstrate the tremendous potential of this technology, especially in analytical microsystems for genomics or cell biology

DNA kinetics in microfabricated devices

The DNA kinetics in micro-capillary electrophoresis is presented. The mobility and diffusion coefficient of 14bp-DNA fragments as a function of concentration in two types of separation sieving matrices, hydroxyethylcellulose (HEC) polymer solution and agarose gel, are extracted through a series of experiments performed in microfabricated devices. In addition, the motion of a DNA plug through a miter bend and splitting a plug in a branch are quantitatively characterized. The concept of equivalent length is introduced to quantify the effect of a bend on the DNA plug motion. In a branching system, a simple kinematic relationship was discovered relating the quantity of DNA in each downstream branch to its relative channel cross-sectional area