"Cross-stealing" technique for septal perforation closure.

The authors described a technique for the surgical repair of anterior septal perforations of medium size (up to 2 cm). This technique is based on two mucoperichondral (mucoperiosteal) flaps, one from each side of the septum. Four patients have been treated in this way, resulting in permanent and complete closure in three of them.

A-mode diagnostic ultrasound of maxillary sinuses: possibilities and limitations.

The diagnostic possibilities and limitations of A-mode ultrasound of maxillary sinus diseases are presented. A group of 219 subjects suffering from various sinus diseases was examined. All cases were analyzed in parallel by means of X-rays, sinoscopy and ultrasonography.

Stimulation of human nitric oxide synthase by tetrahydrobiopterin and selective binding of the cofactor.

To check the stimulatory potency of the tetrahydro forms of the two major pteridines occurring in human tissues, neopterin and biopterin, NO synthase was purified 6000-fold from human cerebellum. Tetrahydrobiopterin stimulated the activity up to 4.5-fold in a concentration dependent manner with a maximum above 1 microM, whereas tetrahydroneopterin was completely inactive in concentrations up to 100 microM.

Ca2+/calmodulin-dependent cytochrome c reductase activity of brain nitric oxide synthase.

Nitric oxide acts as a widespread signal molecule and represents the endogenous activator of soluble guanylyl cyclase. In endothelial cells and brain tissue, NO is enzymatically formed from L-arginine by Ca2+/calmodulin-regulated NO synthases which require NADPH, tetrahydrobiopterin, and molecular oxygen as cofactors. Here we show that purified brain NO synthase binds to cytochrome c-agarose and exhibits superoxide dismutase-insensitive cytochrome c reductase activity with a Vmax of 10.