Fluctuation of lipid peroxides and related enzyme activities at time of stroke in stroke-prone spontaneously hypertensive rats

The levels of lipid peroxides, determined as thiobarbituric acid reactive substances (TBARS), and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), were examined in the blood from stroke-prone spontaneously hypertensive rats (SHRSP), with and without cerebral lesions, and normotensive Wistar Kyoto (WK) rats. The levels of TBARS in the blood from healthy SHRSP were not significantly different from those of WK rats, while the values of SHRSP (male) with stroke were more than twice as high as those of healthy SHRSP. The activities of SOD and GSH-Px in stroke SHRSP were also statistically different from those of healthy SHRSP.

Ion-exchange chromatographic separation and fluorometric detection of guanidino compounds in physiologic fluids

A high-performance liquid chromatographic procedure has been developed for the separation and fluorometric detection of guanidino compounds in physiologic fluids. All guanidino compounds were separated on a 17 X 0.46 cm cation-exchange column using a stepwise pH gradient. The chromatographic system was designed to enable the use of the specific reagent 9,10-phenanthrenequinone as a means of monitoring the guanidino compounds of physiologic fluids. This new analytical method is so sensitive that it enables the analysis at the picomole level. Our automatic guanidino-compound analyzer was successfully applied to the quantitative determination of all guanidino compounds in physiologic fluids from normal controls and uremic patients.

Quantitative analysis of methylguanidine and guanidine in physiologic fluids by high-performance liquid chromatography-fluorescence detection method

A rapid and sensitive high-performance liquid chromatographic method has been developed for the quantitative analysis of methylguanidine and guanidine in physiological fluids. These quanidino compounds are separated on a 6 x 0.23 cm cation-exchange column with 0.5 M sodium hydroxide solution. The guanidino compounds are detected with a fluorometer, which monitors the fluorescent guanidine derivatives produced by the reaction of the eluted constituents with 9,10-phenanthrenequinone. Sensitivity to sub-nanomole levels of methylguanidine and guanidine is demonstrated. The method was successfully applied to physiological fluids such as serum and cerebrospinal fluid from uremic patients.

Production of prostacyclin-like substance in stroke-prone and stroke-resistant spontaneously hypertensive rats

Activities of aortae to produce prostaglandin (PG) I2-like substance in stroke-prone spontaneously hypertensive rats (SHRSP), stroke-resistant SHR (SHRSR) and normotensive control rats from the Wistar-Kyoto (WK) colony were compared. PGI2-like substance was produced by the incubation of the aortic ring in pH 9.0 borate-buffered saline and the amount produced was estimated by comparison of its anti-aggregatory activity with that produced by known amounts of the sodium salt of synthetic PGI2. Before the development of stroke, amounts of this substance generated in SHRSP and SHRSR were significantly higher than those in WK rats (p less than 0.01 and p less than 0.02, respectively). Remarkably reduced capacity to generate PGI2-like substance was observed in some SHRSP after the development of stroke.

Biomembrane characteristics in stroke-prone spontaneously hypertensive rats (SHRSP)

Biomembrane characteristics in stroke-prone SHR (SHRSP) and stroke-resistant SHR (SHRSR) were examined using erythrocytes as a simplified model. When erythrocytes were exposed to osmotic stress in the process of the migration from a higher to a lower osmotic gradient by the coil planet centrifugation, erythrocytes from SHRSP were hemolyzed at a higher osmotic pressure than those from SHRSR. Such a difference in biomembrane characteristics may be useful for detecting a genetic disposition of stroke.

Glucose metabolism in spontaneously hypertensive rats

Serum glucose levels in SHR (especially SHR selected for a greater hyperglycemic response) tended to be higher at 'fasting' and were significantly higher after peroral glucose administration than those in normotensive WK. However, plasma immunoreactive insulin was not decreased in SHR as compared with WK. No significant acceleration of gluconeogenesis was observed in SHR.