Awakening concentration of desflurane is decreased in patients with obstructive jaundice

BACKGROUND： Some studies suggest that behavioral complications of cholestasis, such as fatigue and pruritus, may be associated with altered neurotransmission in the brain. Because inhaled anesthetics primarily act on ion channels and receptors on the neuronal cell membrane and alter synaptic transmission in the central nervous system,     

Tumor necrosis factor-dependent production of human immunodeficiency virus 1 in chronically infected HL-60 cells

Tumor necrosis factor (TNF) may play a central role in proviral activation and release from latency in cells infected with the human immunodeficiency virus (HIV). We studied viral production and its relation to TNF in a HL-60 cell line (J22-HL-60) infected with a monocytotropic strain of HIV-1JR-FL. Viral production was stimulated to similar levels by TNF, 12-O-tetradecanoyl-phorbol-13-acetate (TPA), and 1,25-dihydroxyvitamin D3 (1,25[OH]2D3). Production of the virus was not suppressed by 3'-azido-3'-deoxythymidine (AZT), indicating that viral production was not caused by superinfection. Low concentrations of TNF (0.1 ng/mL) induced viral production with a short lag period of 8 hours, and this proviral activation was specifically suppressed by anti- TNF antibodies. However, induction of virus production by 1,25(OH)2D3 showed an extended lag period of 2 to 3 days. The effect of 1,25(OH)2D3 on virus production was also blocked by anti-TNF antibodies, which suggests the direct participation of TNF in this process. TNF accumulated in the culture supernatant of cells stimulated with 1,25(OH)2D3 with a kinetics consistent with its involvement in the action of 1,25(OH)2D3 on viral production. The J22-HL-60 cell line produced low levels of virus when cultured in the absence of an external stimulus; however, this basal viral production was suppressed greater than 80% in the presence of anti-TNF antibodies. Corresponding low levels of TNF were detected in the culture supernatants. Viral production decreased slowly with increasing passage of the cells, and no virus was detected in the supernatants of cells maintained in culture for several months. Concomitantly, TNF was no longer detected in the supernatant of these cells, which suggests that endogenous autocrine production of TNF drives viral production in the unstimulated cells. However, viral production was stimulated in these cells by low concentrations (0.1 ng/mL) of added TNF. These results argue for a central role for TNF in HIV proviral activation in chronically infected myeloid cells.     

Quantitation of MR relaxation effects of iron oxide particles in liver and spleen

The relaxation effects and organ distribution of superparamagnetic iron oxide particles for magnetic resonance imaging were measured in rats. T1 and T2 were measured for excised organs, and tissue iron levels were quantified with radiolabeling. Approximately 70% of the injected dose is present in the liver and 10% in the spleen 1 hour after injection. At 20 MHz, the doses required to reduce liver and spleen T2 to half the normal value, as measured with a Carr-Purcell-Meiboom-Gill sequence, were, respectively, 420 and 830 mumol iron injected per kilogram of rat. The transverse relaxation rates increase linearly with injected dose and showed no evidence of saturation. These results suggest that this material is less effective than previously suggested.     

Source of hydrogen peroxide and of chemiluminescence observed in activated human platelet preparations

Human platelet suspensions can be observed to produce small amounts of H2O2 (0.04 nmoles H2O2/min/2.5 X 10(5) cells/cu mm) and measurable chemiluminescence when exposed to target particles for phagocytosis, such as latex spherules. Both H2O2 production and chemiluminescence are characteristic of phagocytosing polymorphonuclear leukocytes (PMN) and analysis of the purified platelets indicates contamination by PMN at the level of 0.2%. The amount of H2O2 produced and the chemiluminescence observed can be duplicated by adding latex spheres to a preparation of PMN at a concentration equivalent to the contaminant in the platelet preparations. We conclude that the H2O2 produced and chemiluminescence observed from activated platelets is due to the presence of small amounts of contaminating PMN. These studies emphasize the importance of controlling for PMN contamination in studies of platelet biochemistry and physiology.