Presence of atrial natriuretic peptide in rat thyroid medullary carcinoma cell line

In 1923, Masson described a neoplastic process consisting of papillary hyperplasia of the endothelial cells, with a consequent obliteration of the vascular lumen, followed later by degenerative changes. Masson coined the term vegetant intravascular haemangioendothelioma, however, these days it is more commonly known as papillary endothelial hyperplasia (PEH), or by the pseudonym, Masson's tumour. Although relatively rare, there are numerous accounts of PEH in the literature, describing its predilection for the head and neck region. Our case report describes the finding of a PEH within the paranasal sinuses, a site not previously mentioned even in the largest of series found on literature search. We will then discuss the relevant histological features of the lesion, and its natural history.     

An improved control method of buried-type IPM bearingless motors considering magnetic saturation and magnetic pull variation

An improved control method of the buried-type interior permanent magnet (IPM) bearingless motors has been presented. It is shown that the conventional method is not applicable to this type of IPM bearingless motor for loaded conditions. In IPM bearingless motors, the armature reaction flux is present due to high magnetic permeance with thin permanent magnets and small airgap length. An increase in d-axis flux linkage is caused by armature reaction as a torque-component flux is increased. Thus, it is likely that magnetic saturation occurs in the stator teeth. In addition, a magnetic attractive force caused by the displacement force factor is dependent on the armature reaction flux. A new decoupling controller for the IPM bearingless motor considering magnetic saturation is proposed in this paper. It also considers the influence of magnetic attractive force variations. In addition, a new parameter identification method for the decoupling controller is also proposed. The new controller is found quite suitable to realize successful stable operation of the experimental IPM bearingless motor.     

Effect of alumina addition on hydroxyapatite biocomposites fabricated by underwater-shock compaction

Hydroxyapatite [HAp; Ca₁₀(PO₄)₆(OH)₂] biocomposites are ceramic materials that exhibit excellent bioactivity, but their inherent low fracture strength and toughness render them unusable for practical applications. Alumina (Al₂O₃) is added to improve in mechanical properties without diminution of biocompatibility. Powder mixtures of HAp and Al₂O₃ in various volume ratios (90:10, 80:20, and 70:30) were compacted by underwater shock waves generated by explosives. High explosives of 6900 m s⁻¹ detonation velocity served as the energy generators. The compacts were sintered at 1473, 1573, and 1673 K in order to investigate the influence of sintering temperature. All compacts were found to be free of defects and to have undergone continuous compositional changes to tricalcium phosphate and tetracalcium phosphate. K_1c showed maximum value with HAp–30vol.% Al₂O₃ that have been sintered at 1673 K for 7.2 ks, and the value of 3.0 MPa m^−1/2 is 2.5 times that of HAp monolithic material. The results of optical microscopy, scanning electron microscopy, X-ray diffraction, and other analyses are reported.     

Enhancement of ectopic bone formation in mice with a deficit in Fas-mediated apoptosis

Bone formation is under the control of cytokines as well as growth factors such as bone morphogenetic proteins (BMP). This suggests the possibility that osteogenesis might be modulated by factors which also modulate the immune system. To test whether immune disorders in the host may influence bone formation, we studied BMP-induced bone formation in a C3H/HeJ strain of mice bearing a mutant gene, the lymphoproliferation gene (lpr) or the generalized lymphoproliferative disease gene (gld), both of which are known to be a Fas deletion mutant and a Fas ligand mutant, respectively, and to induce immune disorders via a deficit in Fas-mediated apoptosis. Crude BMP derived from bovine bone were injected into the muscular tissue in the femur of adult C3H/HeJ mice or C3H/HeJ mice bearing an lpr or gld gene. Quantitative analysis of the resulting ectopic bone formation by X-ray photography 2 weeks after injection revealed that the presence of either the lpr or gld gene caused a bone mass significantly larger in dimension than that seen in the wild type mice. Histological examination also revealed the different influence between these mutant genes on the level of bone formation exhibited by hyaline cartilage and bone trabeculae. Based on these results, we discussed the possible mechanisms of the enhanced ectopic bone formation under the deficit in Fas-mediated apoptosis.     

Time- and dose-dependent pharmacokinetics of L-754,394, an HIV protease inhibitor, in rats, dogs and monkeys

L-754,394 is a potent and specific inhibitor of the HIV-1 encoded protease that is essential for the maturation of the infectious virus. The drug exhibited dose-dependent kinetics in all species studied (rat, dog and monkey); the apparent clearance decreased when the dose was increased. However, the dose-dependency cannot be explained by Michaelis-Menten kinetics. L-754,394 in plasma declined log-linearly with time, but with an apparent half-life that increased with dose. The apparent terminal half-life of L-754,394 in rats increased from 20 min at 0.5 mg/kg i.v. to 118 min at 10 mg/kg i.v. Furthermore, L-754,394 exhibited time-dependent pharmacokinetics. After chronic i.v. doses for 7 days (1 mg/kg/dose/day), the apparent clearance of L-754,394 in rats decreased from 87 ml/min/kg after the first dose to 25 ml/min/kg after the last dose. Similar results were observed in dogs and monkeys. In vitro spectral studies indicated that approximately 40 to 60% of the content of cytochrome P-450 was inactivated when L-754,394 (10 microM) was incubated with rat, dog and monkey liver microsomes in the presence of NADPH. Little or no inactivation of cytochrome P-450 was observed when either NADPH or L-754,394 was omitted. In addition, L-754,394 selectively inhibited CYP 2C11-dependent testosterone 2 alpha- and 16 alpha-hydroxylase activity and CYP 3A1/2-dependent testosterone 6 beta-hydroxylase activity, but not CYP 2D1/2-dependent bufuralol 1'-hydroxylase activity nor CYP 1A2-dependent phenacetin O-deethylase activity in rat liver microsomes.(ABSTRACT TRUNCATED AT 250 WORDS)     

Characteristics of muscular contraction caused by magnetic stimulation

Characteristics of muscular contraction induced by magnetic stimulation were studied using isolated gastrocnemius muscles of a frog. The figure-eight coil position was regarded as 0 degrees when the direction of induced current was parallel to the muscle fiber axis, and 90 degrees when the induced current was perpendicular to the muscle fiber axis. Muscular contraction readily occurred with lower outputs of magnetic stimulation at 0 degrees and 180 degrees, but it was weak at 90 degrees and 270 degrees. Magnetic stimulation did not directly induce muscular contraction but it acted on the synapses forming end plates to muscle cells, and muscular contraction occurred if the direction of the eddy current was parallel to the nerve which innervated the muscle cells.