Surface-area increase in tissue expansion

In this paper, the subject of surface-area gain in tissue expansion is approached from three sides. With the help of a mathematical approach, the theoretical increase in surface area was calculated in relation to the specifications of the expanders. In an in vitro model, these mathematical data were confirmed to be reliable. To determine the real surface-area gain that takes place in vivo, measurements on pigs were performed. It appears that only about 35 percent of the mathematically expected increase in surface area takes place. Moreover, a clear difference was observed between the surface-area gain for the different shapes of tissue expanders.     

Choline Acetyltransferase in Skeletal Muscle from Patients with Myasthenia Gravis

Abstract— Acetylcholine synthesis in homogenates of human intercostal muscle was measured by a radiochemical method. Choline acetyltransferase activity in control muscle was about 20 nmol.g⁻¹.h⁻¹. The enzyme was found only in the endplate area of the muscle. At high substrate concentrations its activity was overshadowed by the acetylcholine synthesizing activity of a different enzyme not saturated by 10 m m -choline. The nonspecific enzyme was present at and away from the endplate area. Choline acetyltransferase in parasternal samples of intercostal muscle from myasthenia gravis patients was about 2.5 times higher than in samples, taken from a more lateral location, of control patients, but the K _m for choline was not altered (0.24 m m ). It is suggested that in myasthenia gravis the shortage of acetylcholine receptors is partially compensated for by increased synthesis, storage, and release of the transmitter.     

The depressed nasofrontal angle in aesthetic rhinoplasty

Certain patients seeking cosmetic rhinoplasty present with a so-called depressed nasofrontal angle. In this condition, the most careful part of the nasal bone is underdeveloped. This gives the illusion of a nasal hump. Complete removal of this hump will create a hypoplastic nose. Partial reduction of the hump and augmentation in the nasofrontal area are indicated in these patients. Autogenous material is preferable for this purpose. A number of patients are presented with illustration of the technique.     

ANALYSIS OF THE PREFERENTIAL RELEASE OF NEWLY SYNTHESIZED ACETYLCHOLINE BY CORTICAL SLICES FROM RAT BRAIN WITH THE AID OF TWO DIFFERENT LABELLED PRECURSORS

—The release of newly synthesized acetylcholine (ACh) by cortical slices from rat brain in the presence of 25 mm -KCl was studied. The slices were incubated for 5 min in a medium containing both [2-¹⁴C]pyruvate and choline labelled with 3 deuterium atoms (choline-d₃) in order to label at the same time the acetyl moiety and the choline moiety of ACh. The non-labelled ACh and the ACh-d₃ were measured by pyrolysis-gas chromatography/mass spectrometry, and the [^I4C]ACh by liquid scintillation counting. It was found that the newly formed [⁴C]ACh as well as the newly formed ACh-d₃ had a more than 2.5 times greater probability of being released than the preformed non-labelled ACh. These findings strongly suggest that it is not simply the ACh synthesized immediately inside the nerve ending membrane from incoming undiluted labelled choline, which is preferentially released, but that all newly formed ACh has a greater probability of being released than preformed ACh. No preferential release of newly formed ACh was observed when the incubation medium contained 5.6 mm -pyruvate instead of 10 mm -glucose + 0.6 mm -pyruvate. The cause of this difference remains unexplained.     

Acetylcholine Synthesizing Enzymes in Frog Skeletal Muscle

Acetylcholine synthesis in homogenates of frog sartorius muscle was measured by a radiometric method with a low blank. Choline acetyltransferase activity was very low (V_max, 2 nmol g¹ h^?1, K_mfor choline, approx. 50 μ, m ). The enzyme was found only in the endplate area and disappeared after denervation; it was inactivated by 4-(1-naphthylvinyl)pyridine. At high substrate concentrations its activity was overshadowed by the acetylcholine-synthesizing activity of a different enzyme not saturated by 10 mm -choline. The non-specific enzyme was present at and away from the endplate area, and it was not affected by denervation.     

Bases and spaces: resources on the web for accessing the draft human genome - II - After publication of the draft

The volume of human genome sequence and the variety of web-based tools to access it continue to grow at an impressive rate, but a working knowledge of certain key resources can be sufficient to get the most from your genome. This article provides an update to Genome Biology 2000, 1(4):reviews2001.1-2001.5.