Dendritic cells (DCs) are strong activators of primary T cell responses. Their priming ability is acquired upon encounter with maturation stimuli. To identify the genes that are differentially expressed upon maturation induced by exposure to Gram-negative bacteria, a kinetic study of DC gene expression was done with microarrays representing 11,000 genes and ESTs (expressed sequence tags). Approximately 3000 differentially expressed transcripts were identified. We found that functional interleukin 2 (IL-2) mRNA, which gave rise to IL-2 production, was transiently up-regulated at early time-points after bacterial encounter. In contrast, macrophages did not produce IL-2 upon bacterial stimulation. Thus, IL-2 is an additional key cytokine that confers unique T cell stimulatory capacity to DCs.

The conformational behavior of four [Ln(DOTA)(H(2)O)](-) systems (Ln = La, Gd, Ho, and Lu) has been characterized by means of ab initio calculations performed in vacuo and in aqueous solution, the latter by using the polarizable continuum model (PCM). Calculated molecular geometries and conformational energies of the [Ln(DOTA)(H(2)O)](-) systems, and interconversion mechanisms, barriers, and (13)C NMR spectra of the [Lu(DOTA)](-) complex are compared with experimental values. For each system, geometry optimizations, performed in vacuo and in solution at the HF/3-21G level and using a 46+4f(n) core electron effective core potential (ECP) for lanthanides, provide two minima corresponding to a square antiprismatic (A) and an inverted antiprismatic (IA) coordination geometry. All the systems are nonacoordinated, with the exception of the IA isomer of the Lu complex that, from in solution calculations, is octacoordinated, in agreement with experimental data. On comparing the in vacuo relative free energies calculated at different theory levels it can be seen that the nonacoordinated species dominates at the beginning of the lanthanide series while the octacoordinated one does so at the end. Furthermore, on passing along the series the IA isomer becomes less and less favored with respect to A and for the Lu complex a stabilization of the IAisomer is observed in solution (but not in vacuo), in agreement with the experimental data. Investigation of the A<-->IA isomerization process in the [Lu(DOTA)](-) system provides two different interconversion mechanisms: a single-step process, involving the simultaneous rotation of the acetate arms, and a multistep path, involving the inversion of the cyclen cycle configuration. While in vacuo the energy barrier for the acetate arm rotation is higher than that involved in the ring inversion (23.1 and 13.1 kcal mol(-)(1) at the B3LYP/6-311G level, respectively), in solution the two mechanisms present comparable barriers (14.7 and 13.5 kcal mol(-)(1)), in fairly good agreement with the experimental values. The NMR shielding constants for the two isomers of the [Lu(DOTA)](-) complex have been calculated by means of the ab initio GIAO and CSGT methods, and using a 46-core-electron ECP for Lu. The calculated (13)C NMR chemical shifts are in close agreement with the experimental values (rms 3.3 ppm, at the HF/6-311G level) and confirm the structural assignment of the two isomers based on experimental NMR spectra in solution. The results demonstrate that our computational approach is able to predict several physicochemical properties of lanthanide complexes, allowing a better characterization of this class of compounds for their application as contrast agents in medical magnetic resonance imaging (MRI).

A set of atomic radii used for the construction of solute cavities in the framework of the polarizable continuum model (PCM) is extended and validated with the aim of supporting the investigation of lanthanide(III) complexes in aqueous solution. The parameterization of the atomic radii for the whole Ln(III) series is performed by minimizing the differences between the experimental and the calculated standard hydration free energies of the ions calculated at the HF level. The optimized radii show a remarkable linear relationship with effective ionic radii and well reproduce the experimental hydration free energies also when electron correlation effects are included in the calculations. We have next validated a mixed discrete continuum model in which a supermolecule formed by the ion and by water molecules in the first hydration shell is immersed in a polarizable continuum. The molecular structures, the relative stability of the octa- with respect to the nonahydrated species, and the ion hydration free energies have been calculated for the neodymium(III) and ytterbium(III) aqueous ions. Results are in agreement with experimental evidence, both from structural and energetic standpoints. The molecular structures optimized including surrounding effects are in better agreement with the experimental structures than the in vacuo geometries. Moreover, the results show that the energetic properties of these systems in aqueous solution can be effectively calculated by using the structures optimized in vacuo, and including correlation effects in the gas-phase reaction of complex formation.

A double‐blind, randomized, controlled study was performed in 90 full term infants to evaluate dose‐related bifidogenic effects of a new synergistic mixture of galacto‐oligosaccharides (GOS) and fructo‐oligosacharides (FOS). The GOS/FOS mixture showed a dose‐dependent stimulatory effect on the intestinal growth of bifidobacteria. Also stool consistency and faecal pH were positively affected.

Objective: To evaluate the potential role of quantitative ultrasound (QUS) investigation in assessing the osteopenia of prematurity. Design: QUS parameters measured at the time of discharge were related to the anthropometric characteristics and age (postnatal and gestational) of 51 (34 female and 17 male) preterm infants fed fortified human milk. Methods: QUS evaluation was performed at the humerus (h) by measuring two parameters: ultrasound velocity (hSOS, in m/s) and bone transmission time (hBTT, in ms). A group of 43 term infants (29 female and 14 male) was also evaluated. Results: In preterm infants, significant correlations were found for hSOS and hBTT vs gestational age (r ¼ 0.504, 0.477, P , 0.0001), length (r ¼ 0.641, 0.594, P , 0.0001) and weight (r ¼ 0.580, 0.562, P , 0.0001) at birth, and length (r ¼ 0.341, 0.332, P , 0.05) and weight (r ¼ 0.331, r ¼ 0.362, P , 0.05) at QUS measurement. In preterm infants, both QUS parameters were negatively correlated with age (r ¼ 2 0.536, P , 0.0001, r ¼ 2 0.443, P , 0.001) and were significantly lower than in the term infants (hSOS: 1664^42 m/s vs 1734^28 m/s, P , 0.0001; hBTT: 0.58^0.24 ms vs 1.06^0.15 ms, P , 0.0001) even when adjusted for body length (P , 0.05). In preterm infants, hSOS was also negatively correlated with postconceptional age (r ¼ 2 0.322, P , 0.05).Conclusions: This study suggests that bone mineral accrual is mainly determined by the development in utero, and that prematurity induces a halt in the bone development process in the early postnatal period. QUS parameters are correlated with the severity of prematurity and might therefore have clinical applications when bone maturation in early life needs to be determined.

No abstract

Transgenic mice over-expressing calcitonin gene-related peptide (CGRP) in osteoblasts have increased bone density due to increased bone formation, thus suggesting that CGRP plays a role in bone metabolism. In this study we determined the relationship between CGRP, the canonical Wnt signaling and apoptosis in human osteoblasts (hOBs) in consideration of the well-documented involvement of this pathway in bone cells. Primary cultures of hOBs were treated with CGRP 10(-8) M. Levels of β-catenin, which is the cytoplasmic protein mediator of canonical Wnt signaling, and mRNA were determined. CGRP increases both the expression and the levels of cytoplasmic β-catenin by binding to its receptor, as this effect is blocked by the antagonist CGRP(8-37). This facilitatory action on β-catenin appears to be mediated by the inhibition of the enzyme GSK-3β via protein kinase A (PKA) activation. GSK-3β is a glycogen synthase kinase that, by phosphorylating β-catenin, promotes its degradation by the proteosomal machinery. Moreover, the peptide is able to inhibit hOBs apoptosis stimulated by dexamethasone or by serum deprivation, possibly through the accumulation of β-catenin, since the inhibitor of PKA activity H89 partially prevents the antiapoptotic effect of the peptide. In conclusion CGRP, released by nerve fibers, exerts its anabolic action on bone cells by stimulating canonical Wnt signaling and by inhibiting hOBs apoptosis, thus favoring local bone regeneration.

This study was designed to determine the modulatory effect of estrogen on mechanical stimulation in bone. Trabecular and cortical bone compartments of ovariectomized rats exposed to whole-body vibration of different amplitudes were evaluated by peripheral quantitative computed tomographic (pQCT) analysis and histomorphometry and compared to controls not exposed to vibration. Rats underwent whole-body vibration (20 minutes/day, 5 days/week) on a vibration platform for 2 months. The control rats were placed on the platform without vibration for the same time. We divided rats into six groups: a sham control (SHAM); a sham vibrated (SHAM-V) at 30 Hz, 0.6 g; a SHAM-V at 30 Hz, 3g; an ovariectomized control (OVX); an ovariectomized vibrated (OVX-V) at 30 Hz, 0.6 g; and an OVX-V at 30 Hz, 3g. In vivo, pQCT analyses of the tibiae were performed at the start of the experiment and after 4 and 8 weeks. After 8 weeks the tibiae were excised for histomorphometric and for in vitro pQCT analyses. In the SHAM-V group, vibration had no effect upon the different bone parameters. In the OVX-V group, vibration induced a significant increase compared to the OVX group of the cortical and medullary areas (P < 0.01) and of the periosteal (P < 0.01) and endosteal (P < 0.05) perimeters at the 3 g vibration. The strain strength index increased in the OVX-V group significantly (P < 0.01) at the higher vibration. The results showed that low-amplitude, high-frequency whole-body vibration is anabolic to bone in OVX animals. The osteogenic potential is limited to the modeling of the bone cortex and depends on the amplitude of the vibration.