A highly sensitive and reversed-phase high-performance liquid chromatographic method for the determination of the enantiomeric composition of ibuprofen in rat plasma is described. The method is based on the resolution of the diastereomeric amides formed on reaction of the ibuprofen enantiomers with (-)-2-[4-(1-aminoethyl)phenyl]-6-methoxybenzoxazole ((-)-APMB) in the presence of 2,2'-dipyridyl disulphide (DPDS) and triphenylphosphine (TPP) in dichloromethane. The reaction mixture was allowed to stand at room temperature for 5 min, and the reaction was completed by evaporation with a stream of nitrogen at 40 degrees C. The minimum quantifiable concentrations were 0.2 microgram/mL and 0.4 microgram/mL for S-ibuprofen and R-ibuprofen, respectively, in a 10 microL injection volume. The method was applied to the determination of enantiomeric ibuprofen in plasma after oral administration to rats.

2,2'-Dipyridyl↗

PubMedDate not supplied

Alteration in 1,2-diacylglycerol level and its fatty acid composition in hearts during the growth of hamsters.

We measured the amount of 1,2-diacylglycerol (DAG) and its fatty acid composition in hamster hearts of various ages because 1,2-DAG has been recognized to be one of the intracellular second messengers. The highest level in 1,2-DAG was detected in 30-day-old hamster hearts. The heart weight increased about 2.5 times between 30 and 90 days of age. Hamster hearts at 90 days of age had 72% of the 1,2-DAG content at 30 days of age. The amount of 1,2-DAG at 240 days of age was a little lower than that in 90-day-old and 160-day-old hamsters, whereas there was no significant increase in heart weight and only a little gain in body weight between 90 and 240 days of age. The analysis of the fatty acid composition of 1,2-DAG showed an increase in the percentage of 18:0 accompanied by a change in the percentages of other fatty acids with the growth of hamsters. The largest amount of arachidonic acid expressed as 20:4 (n-6) was found at 30 days of age. On the other hand, triglyceride, cholesterol, and major phospholipid components of hamster hearts increased in accordance with growth. In particular, the increase in triglyceride content was remarkable, indicating that myocardial lipidosis may be induced by aging. These results demonstrate that 1,2-DAG may be involved in the synthesis of protein during heart growth and that the alteration of its fatty acid composition is related to the growth of hamsters.

Animals↗

PubMedDate not supplied

1,2-diacylglycerol content in myocardium from spontaneously hypertensive rats during the development of hypertension.

1,2-Diacylglycerol (DAG) has been considered to play an important role as an activator of protein kinase C in the signal transduction of inositol phospholipid metabolism. To examine the relation of 1,2-DAG in heart tissues to cardiac hypertrophy associated with hypertension, we measured the amount of 1,2-DAG in spontaneously hypertensive rat (SHR) hearts at 4, 10 and 20 weeks of age, and in age-matched normotensive Wistar-Kyoto (WKY) rat hearts using thin-layer chromatography with flame ionization detection (TLC-FID). Significant cardiac hypertrophy was found in 4-week-old SHR, while SHR did not yet have significant hypertension. Major phospholipids such as phosphatidylcholine and phosphatidylethanolamine increased from 4 to 20 weeks in the myocardium, but there was no difference between the two strains. The cholesterol levels of 4- and 20-week-old SHR were significantly higher than WKY rats. The 1,2-DAG contents of SHR hearts were significantly higher than WKY rats at 4 weeks. An increase in the RNA content was also observed in 4-week-old SHR hearts. However, analysis of the fatty acid composition of 1,2-DAG revealed no difference between the two strains. However, there was no significant difference in the 1,2-DAG content or in its fatty acid composition between SHR and WKY rat hearts at 10 and 20 weeks of age. It is suggested that an increase in the 1,2-DAG content of SHR hearts during the early stages appears related to the initiation of cardiac hypertrophy in SHR hearts before developed hypertension.

Aging↗

PubMedDate not supplied

A new antithrombogenic RV-PA valved conduit.

A new antithrombogenic right ventricular (RV)-pulmonary artery (PA) valved conduit was developed using a bovine jugular vein containing a natural valve. To maintain the natural and mechanical properties of the venous tissue, a hydrophilic cross-linking reagent, glycerol polyglycidyl ether polyepoxy compound (PC) was used instead of glutaraldehyde (GA). Moreover, to induce antithrombogenicity, heparin was bonded to the inner surface of the bovine jugular vein cross-linked with PC. Conduits of 18 to 20 mm inner diameter (ID) were implanted between the RV and PA in nine dogs weighing 7-17 kg, with the native main PA being ligated proximally. The handling and suturing of the graft was easy and adaptable, and the anastomosis was completed with excellent coaptation and no blood leakage at the suture lines. All animals were chronic survivors, but one animal died of hematemesis on the 438th postoperative day. Grafts were explanted from 182 to 385 days after implantation. The luminal surface of the conduits were white, glistening, and smooth with good coaptation of the cusps, without calcification or degenerative changes except for one cusp that showed a minimal deformation with a small thrombus. Macroscopic and microscopic observation showed that there were no thrombi at the anastomotic lines, but small thrombi on the luminal surface of the conduits near the cusps and in some cusps. Endothelium-like cells were noticed on the luminal surface of the graft, except in the area near the cusps, and on one cusp at 196 days after surgery. These results indicated that the new RV-PA valved conduit provided adequate antithrombogenicity by temporary slow heparin release, followed later by endothelialization of the graft in a low pressure system at 1 year after implantation.

Animals↗

PubMedDate not supplied

Time-dependent increases in syndecan-1 and fibroglycan messenger RNA expression in the infarct zone after experimentally induced myocardial infarction in rats.

BACKGROUND: Syndecan-1 and fibroglycan, heparan sulphate proteoglycans, play important roles in extracellular matrix formation via their biological functions. OBJECTIVE: To examine experimentally the sequential changes in syndecan-1 and fibroglycan messenger RNA (mRNA) expression after acute myocardial infarction. MATERIALS AND METHODS: The left coronary arteries of male Sprague-Dawley rats were ligated and the hearts were excised on days 1-14, 28 and 42. Syndecan-1 and fibroglycan mRNA expression in the infarct and non-infarct zones and in sham-operated hearts was determined by reverse transcriptase-polymerase chain reaction. Amplified products were quantified by densitometry of the electrophoresed bands stained with ethidium bromide and standardized relative to the glyceraldehyde 3-phosphate dehydrogenase or beta-actin mRNA expression. Northern hybridization was also performed in the infarct and non-infarct zones on day 3. RESULTS: Expression both of syndecan-1 and of fibroglycan mRNA began to increase on day 2. The expression attained maximum levels on day 3. The maximum levels of syndecan-1 and fibroglycan expression were, respectively, sevenfold and fivefold the preligation level and the level in the sham-operated hearts. The levels remained elevated until day 14, whereupon they declined gradually, returning to the control levels by around day 42. Northern blotting also demonstrated that there was an increased expression both of syndecan-1 and of fibroglycan mRNA in the infarct compared with that in the non-infarct zone on day 3. CONCLUSION: Our results demonstrated that there are sequential increases in the expression both of syndecan-1 and of fibroglycan mRNA in the infarct zone after experimentally induced myocardial infarction in rats, suggesting that these proteoglycans play some role in the pathological course of infarction.

Animals↗