Effects of N-nitropyrazoles on ocular blood flow of rabbits and retinal function recovery of rat eyes after ischemic insults

Real-time fingerprinting of structural isomers using laser induced breakdown spectroscopy

Laser induced breakdown spectroscopy (LIBS) has surfaced as an attractive alternative to mass spectrometry and wet chemistry methods for chemical identification, driven by its real-time, label-free nature. Rapid analysis needs, especially in high-energy materials and pharmaceutical compounds, have further fueled an increasing number of refinements in LIBS. Yet, isomers are seldom identifiable by LIBS as they generate nearly identical spectra. Here we employ a suite of chemometric approaches to exploit the subtle, but reproducible, differences in LIBS spectra acquired from structural isomers, a set of pyrazoles, to develop a sensitive and reliable segmentation method. We also investigate the possible mechanistic principles (causation) behind such spectral variations and confirm their statistically significant nature that empowers the excellent classification performance.

Effects of Dihydrogenation of Flavones and Number of Hydroxy Groups in the Molecules on Ocular Blood Flow in Rabbits and Retinal Function Recovery in Rats

PURPOSE

It has been found that the number of hydroxy groups in the molecule of flavones and flavanones affect the ocular blood flow significantly. However, the effects of dihydrogenation of flavones into flavanones on ocular blood flow and retinal function recovery have not been studied and required investigation.

METHODS

The colored microsphere technique and electroretinography method were used for the study of ocular blood flow and retinal function, respectively.

RESULTS

Maximum effects on ocular blood flow were obtained when there were 3 hydroxy groups in the molecule of flavones and flavanones. Dihydrogenation of flavones to flavanones increased the ocular blood flow further. The same is true for retinal function recovery after ischemic insult.

CONCLUSION

These results indicate that hydrogenation is an excellent way to convert natural flavones into more potent compounds of flavanones.

Release of nitric oxide by N-nitropyrazoles in rabbit lacrimal gland cell culture

PURPOSE

In order to prove the effects of N-nitropyrazoles to increase ocular blood flow and to facilitate retinal function after ischemia are due to nitric oxide (NO) release, eleven N-nitropyrazoles which are known NO donors were used to test their ability to produce NO in rabbit lacrimal gland (RLG) cell cultures.

METHODS

Nitropyrazoles (0.3-3 microg/ml) were added into RLG cell culture and the NO produced was determined with nitrate-nitrite colorimetric assay.

RESULTS

All nitropyrazoles (11 compounds) tested produced NO in various degrees with the highest degree by 13 fold over control (DN-5) and the lowest level by only 2.8 fold over control (DN-7).

CONCLUSION

The results indicated that NO is involved in ocular blood flow increase and retinal function recovery after ischemia by N-nitropyrazoles. However, there is no potency relationship between in vitro data and in vivo data, which is understandable because the experimental environments are different.

Relationship between nitric oxide production and choroidal blood flow

PURPOSE

To invent a drug which can specifically facilitate choroid blood flow via increase of nitric oxide (NO).

METHOD

Cell culture was used for in vitro experiments to determine the production of NO by NO donors and colored microsphere technique was used for in vivo experiments to determine the blood flow in various tissues of rabbit eyes.

RESULTS

ZX-5 and ZX-4 are two geographic isomers with ZX-5 as trans-form and ZX-4 as cis-form. (1-phenyl-3-[3-methoxy-2-propoxy-5-[4-(3,4,5-trimethoxy-phenyl)-1,3-d lane-2-yl]phenyl]thiourea). It was found that ZX-5 released significant amount of NO at 3, 10, 30 microg/ml concentrations and increased choroid blood flow at 1%, 50 microl instillation into eyes. It was not effective on the blood flow of iris or ciliary body. The corresponding ZX-4 was not effective on ocular blood flow nor it released NO.

CONCLUSION

ZX-5 can specifically increase the choroidal blood flow which could be useful to suppress the choroidal neovascularization in age-related macular degeneration (AMD). It is hoped that ZX-5 type of compounds could be used for the treatment/prevention of AMD in the elderly.