Untitled

Abstract

The effects of platelet activating factor (PAF) and its cell analogs 1-O-alk-1;-enyl-2-acetyl-sn-glycero-3-phosphocholine (1-alkenyl-PAF) and 1-acyl-2-acetyl-sn-glycero-3-phosphocholine (1-acyl-PAF) on chemotaxis of human leukocytes in vitro and their inflammatory and antiinflammatory activities in vivo were studied. Both analogs stimulated chemotaxis of human leukocytes in agarose gel. PAF and 1-alkenyl-PAF induced rat paw edema in the range of doses 0.1-10 and 10-100 micro g per paw, respectively. Paw edema induced by 1-acyl-PAF (10-100 micro g per paw) was more pronounced than that induced by PAF or 1-alkenyl-PAF. The latter also exhibited significant antiinflammatory effect by inhibiting PAF- or carrageenan-induced rat paw edema, and this effect exceeded that of dexamethasone. In these models of inflammation 1-acyl-PAF did not exhibit any antiinflammatory activity. The data suggest that PAF is not the only cell phospholipid mediating inflammation--its cell analogs, 1-acyl-PAF and 1-alkenyl-PAF, may also be involved into the inflammatory response. Possible interrelationships between cellular synthesis of 1-acyl-PAF, its formation in oxidized LDL, biological effects of lysolecithin, and penetration of LDL into the arterial wall are discussed.

Spectroscopy of 142NdO: New results

“…The principal results were the first observation and characterization of the (2)2, (2)3, (2)5, and (1)6 states in their lowest vibrational level and of new vibrational levels in the (1)5 and (2)4 states (m = 1 and m = 1, 2, respectively). Noting that the energies of the observed low-lying states agree very well with those calculated by Kulikov [4] using ligand field theory, the authors concluded that these states arise from the atomic ion Nd 2+ [4f 3 ( 4 I)6s] configuration which is expected to give 56 states, all predicted to lie below 8000 cm À1 . However, for several states only rough estimates of the parameters could be proposed, and a number of fluorescence patterns remained unexplained.…”

“…However, he noticed a splitting of the lines due to X doubling effects in the upper level of the transition, for J > 20 up to J 0 = 29 (the highest level observed in his spectra and also in ours: the regular line pattern breaks off abruptly). The lines reported by Kaledin et al [2] correspond to the upper (a) sublevels identified by Kulikov [4]. We have reanalysed this band and observed the splitting found by Kulikov.…”

“…They failed to observe X doubling up to J 0 = 30. Kulikov [4] reanalysed this transition and confirmed the precedent rotational analysis. However, he noticed a splitting of the lines due to X doubling effects in the upper level of the transition, for J > 20 up to J 0 = 29 (the highest level observed in his spectra and also in ours: the regular line pattern breaks off abruptly).…”

“…Three sets of P, Q, R, fluorescence transitions are observed in all three cases, terminating, respectively, in the levels (1)6 m = 0, (2) Based on the ligand field theory predictions of Kulikov [4], the [4.1] state has been identified as (2)6. The value of X for the [17.3] state cannot be given with confidence as P, Q, R fluorescence transitions exist to X = 5 and X = 6 levels as well; certainly this state borrows some X = 5 and/or X = 6 characters by interaction with neighbouring states.…”

“…These were classified into 10 systems, and spectroscopic constants of a number of levels from rotational analyses of 0-0 bands were given. Kulikov and co-workers [3,4] then used a tunable laser operating between 568 and 628 nm and also the 488 nm line of an Ar + laser to excite fluorescence were able to obtain information about three low-lying states. These works clearly established the X = 4 symmetry of the ground state.…”