Brain ischemia was produced in gerbils by contemporary occlusion of both carotid arteries. Definite changes of the energy state in brain demonstrated that carotid occlusion was effective. At short time intervals from occlusion the free fatty acid content, their distribution, and their concentration and specific activity in arachidonate were determined in brain. A noticeable increase of the arachidonate pool and that of other free fatty acids was detected at very early times from occlusion. Specific activity by arachidonate increased after 30-60 seconds from ligation. By examining arachidonate distribution and specific activity in neutral and polar lipids of brain, it is concluded that phosphatidylcholine and phosphatidylinositol represent the more important source for the release of arachidonate during ischemia. Enzymic-mediated phenomena produced free arachidonate from lipids by a mechanism yielding diglycerides further transformed into fatty acids and by lipid degradation through phospholipase A activity.

Animals↗

PubMedDate not supplied

[An ultrastructural analysis of dentin treated with chemical agents].

Dental last generation bonding systems require the total removal of smear layer and smear plug by chemical solutions. Intermediate fluid resin can penetrate the dentinal tubes obtaining a better anchorage to the dental structures. The department of Operative dentistry of the University of Rome "La Sapienza" has carried research observing by means of the SEM the ultrastructural aspect of smear layer and the effect of dentin treatment with five different chemical agents.

Acrylic Resins↗

PubMedDate not supplied

Dentinal adhesive with composite restorations: a clinical and microstructural evaluation.

It is generally accepted that the application of dentin-enamel adhesive should involve not only the etched enamel but also the dentinal surface. For this purpose, new bonding agents requiring dentin etching and the combined use of bifunctional groups (Primers) as well as hydrophilic resins have been introduced. This study used scanning electron microscopy to analyze the relationship between dentin and fluid resin of three bonding agents. The results demonstrated that the adhesive monomers easily penetrated the etched dentin, sealing the dentinal tubules and creating a resin dentin interdiffusion zone (hybrid layer). As a result, the microleakage between dentin and resin composite restorations, responsible for postoperative tooth sensitivity, pulpal inflammatory reaction, and secondary decay, is greatly reduced.

Acid Etching, Dental↗

PubMedDate not supplied

[Primary choledocholithiasis after side-to-side choledochojejunostomy].

Primary choledocholithiasis represents a quite unusual sequela of biliary tract surgery. Primary stones originate in the common bile duct and are soft, smooth, with a yellowish or brown-reddish colour, reproducing the shape of the duct in which arise. The Authors report a review of the cases observed in the division of General and Vascular Surgery-Department of Surgery and Surgical Emergencies of the University of Perugia. From January 1988 to December 1993, 577 laparotomic biliary tract operations were performed, and in 8 cases a re-operation was needed. Among the latter, particularly interesting were 2 cases of primary choledocholithiasis occurred in two patients with bilio-digestive anastomosis previously performed, i.e. two side-to-side Roux-en-Y or Braun loop choledochojejunostomies, respectively. Therefore, primary lithiasis following a choledochojejunostomy occurred when the bilio-digestive anastomoses were performed with the indication of a curative re-operation on the biliary tract. On the contrary, most choledochojejunostomies are performed as a palliative procedure in patients presenting a low survival rate not allowing to develop a Sump Syndrome and a consequent choledocholithiasis, which are long-term complications.

Biliary Tract Surgical Procedures↗

PubMedDate not supplied

Proceedings: DNA/protein ratios in neuronal and glial cells of the rat during myelination.

Explore the source record for details and available documents.

Aging↗