Sixteen-channel coherent broadcast network at 155 Mbit/s

An experimental 155.52 Mb/s coherent broadcast network with 16 channels using a conventional distributed feedback (DFB) laser operating at 1540 nm is described. It includes absolute laser frequency stabilization, a fiber span of 74.4 km, and a balanced polarization-diversity single-filter frequency-shift keying (FSK) heterodyne receiver. At a channel spacing of 8.5 GHz a power penalty of 0.3 dB is incurred due to adjacent channel crosstalk     

Stereochemical influence on the stability of radio-metal complexes in vivo. Synthesis and evaluation of the four stereoisomers of 2-(p-nitrobenzyl)-trans-CyDTPA

Distinct differences in in vivo stability of the two diastereomeric C-Functionalized CyDTPA chelating agents, (CHX-A DTPA and CHX-B DTPA, both racemates), as recently reported prompted further investigation as to why differences in configuration produced striking effects on the in vivo stability of their yttrium complexes. To this end, the four individual component stereoisomers of CHX-A and CHX-B were synthesized and ability to bind yttrium was investigated both in vitro and in vivo.     

Sizzled: a secreted Xwnt8 antagonist expressed in the ventral marginal zone of Xenopus embryos

An expression cloning screen was used to isolate a novel gene homologous to the extracellular cysteine-rich domain of frizzled receptors. The gene (which we called sizzled for secreted frizzled) was shown to encode a soluble secreted protein, containing a functional signal sequence but no transmembrane domains. Sizzled (szl) is capable of inhibiting Xwnt8 as assayed by (1) dose-dependent inhibition of siamois induction by Xwnt8 in animal caps, (2) rescue of embryos ventralized by Xwnt8 DNA and (3) inhibition of XmyoD expression in the marginal zone. Szl can dorsalize Xenopus embryos if expressed after the midblastula transition, strengthening the idea that zygotic expression of wnts and in particular of Xwnt8 plays a role in antagonizing dorsal signals. It also suggests that inhibiting ventralizing wnts parallels the opposition of BMPs by noggin and chordin. szl expression is restricted to a narrow domain in the ventral marginal zone of gastrulating embryos. szl thus encodes a secreted antagonist of wnt signaling likely involved in inhibiting Xwnt8 and XmyoD ventrally and whose restricted expression represents a new element in the molecular pattern of the ventral marginal zone.     

Raloxifene and estrogen: comparative bone-remodeling kinetics

The pattern of changes in human bone remodeling produced by raloxifene (60 mg/day) was compared to that of estrogen (given as hormone replacement therapy) in 33 early postmenopausal women randomly assigned to raloxifene, estrogen, or no treatment. Remodeling was measured using calcium tracer kinetic methods employed under a constant diet and full metabolic balance conditions. Studies were performed at baseline and, to detect both early and late remodeling changes, at 4 and 31 weeks of treatment. Both raloxifene and estrogen produced a significant positive calcium balance shift at each treatment measurement point: +74 and +60 mg/day at 4 weeks, and +60 and +91 mg/day at 31 weeks for raloxifene and estrogen, respectively. Externally, this balance change was due to a highly significant fall in the urinary calcium level and marginal improvement in calcium absorption efficiency. Internally, bone resorption was significantly reduced at both measurement points: -64 and -60 mg/day at 4 weeks, and -82 and -162 mg/day at 31 weeks for raloxifene and estrogen, respectively. Bone formation was not significantly affected by either agent at 4 weeks; at 31 weeks, formation was reduced by estrogen, but not by raloxifene. Thus, at 4 weeks, the general pattern of remodeling change was identical for the two agents. At 31 weeks, remodeling suppression was greater for estrogen than for raloxifene; however, remodeling balance was the same for the two agents. We conclude that raloxifene and estrogen affect the bone remodeling apparatus similarly, and that raloxifene, therefore, is acting on bone as an estrogen agonist.     

RS-102221: a novel high affinity and selective, 5-HT2C receptor antagonist

The 5-HT2C receptor is one of three closely related receptor subtypes in the 5-HT2 receptor family. 5-HT2A and 5-HT2B selective antagonists have been described. However, no 5-HT2C selective antagonists have yet been disclosed. As part of an effort to further explore the function of 5-HT2C receptors, we have developed a selective 5-HT2C receptor antagonist, RS-102221 (a benzenesulfonamide of 8-[5-(5-amino-2,4-dimethoxyphenyl) 5-oxopentyl]-1,3,8-triazaspiro[4.5]decane-2,4-dione). This compound exhibited nanomolar affinity for human (pKi = 8.4) and rat (pKi = 8.5) 5-HT2C receptors. The compound also demonstrated nearly 100-fold selectivity for the 5-HT2C receptor as compared to the 5-HT2A and 5-HT2B receptors. RS-102221 acted as an antagonist in a cell-based microphysiometry functional assay (pA2 = 8.1) and had no detectable intrinsic efficacy. Consistent with its action as a 5-HT2C receptor antagonist, daily dosing with RS-102221 (2 mg/kg intraperitoneal) increased food-intake and weight-gain in rats. Surprisingly, RS-102221 failed to reverse the hypolocomotion induced by the 5-HT2 receptor agonist 1-(3-chlorophenyl)piperazine (m-CPP). It is concluded that RS-102221 is the first selective, high affinity 5-HT2C receptor antagonist to be described.