Metal–Metal Electronic Coupling insyn andanti Stereoisomers of Mixed-Valent (FeCp)2-, (RhL2)2-, and (FeCp)(RhL2)-as-Indacenediide Ions

The extent of metal-metal electronic coupling was quantified for a series of syn and anti stereoisomers of (FeCp)(2)-, (RhL(2))(2)- and (FeCp)(RhL(2))- (L(2)=1,5-cyclooctadiene (cod), L=CO) as-indacenediide mixed-valent ions by spectroelectrochemical and DFT studies. The effect of the syn/anti orientation of the metal units with respect to the planar aromatic ligand indicates that electron transfer occurs through the bridge rather than through space. The nature of the metal was found to be crucial: while homobimetallic diiron species are localised valence-trapped ions (Class II), the dirhodium analogues are almost delocalised mixed-valent ions (borderline and Class III). Finally, despite their redox asymmetry, even in the heterobimetallic iron-rhodium as-indacenediide complexes, strong metal-metal coupling is present. In fact, oxidation of the iron centre is accompanied by electron transfer from rhodium to iron and formation of a reactive 17-electron rhodium site. syn and anti Fe-Rh as-indacenediide complexes are rare examples of heterobimetallic systems which can be classified as borderline Class II/Class III species.

Tuning the Electronic Communication in Heterobimetallic Mixed-Valence Ions of (1-Ferrocenyl)- and (2-Ferrocenyl)indenyl Rhodium Isomers

A series of heterobimetallic complexes of general structure [RhL(2){eta(5)-(2-ferrocenyl)indenyl}] (L(2)=cod, nbd, L=CO; cod=cyclooctadiene; nbd=norbornadiene) has been synthesised with the aim of tuning the metal-metal interaction in their mixed-valence ions generated both by chemical and electrochemical oxidation, and the results are compared with those obtained for [RhL(2){eta(5)-(1-ferrocenyl)indenyl}] isomers. Crystallographic studies and DFT calculations provide a detailed description of the structural and electronic features of these complexes evidencing a significant difference in the extent of planarity of the flexible bridging ligand between the 1- and 2-ferrocenyl isomers. Independent experimental probes, in particular the potential splitting in the cyclic voltammograms and the IT bands in the near-IR spectra, are rationalised in the framework of Marcus-Hush theory and at quantum chemistry level by DFT and TD-DFT methods. These methods allow us to establish a trend based on the magnitude of iron-rhodium electronic coupling H(ab) ranging from valence trapped to almost delocalised ions. The quasi planar bridge and the olefin ancillary ligands make [Rh(nbd){eta(5)-(2-ferrocenyl)indenyl}](+) and [Rh(cod){eta(5)-(2-ferrocenyl)indenyl}](+) rare examples of heterobimetallic systems which can be classified as borderline Class II/Class III species.

Formation of a solubilized cobalt block oligomer from a M2L-type double helicate

The multi-dentate ligand, 2,3,5,6-tetrakis(2,2'-bipyridyl)pyrazine (L) and divalent cobalt self-assemble to a block co-polymer-like oligomer in solution, which contains at least the L(7)Co(8) fragment. The extent of oligomerization is sensitive to the water content in acetonitrile solution. In the solid state, the simple monomer [LCo(2)(CH(3)CN)(4)][ClO(4)](4) is isolated. The X-ray structure of the crystallized material (containing four CH(3)CN solvate molecules) reveals a double-helical complex with two heptadentate Co(II) sites, and a helical pitch of approximately 28.1 A. Coupled Co(I/II) redox processes are observed between the two metal centres.

Minimally invasive pharyngo-laryngo-esophagectomy: a salvage procedure for recurrent postcricoid esophageal cancer

Hypopharyngeal and cervical esophageal tumors represent 5-10% of all esophageal neoplasms and are challenging for both surgeons and oncologists, because the choice of the adequate therapeutic strategy is not clearly defined and therefore difficult. In fact, although surgical treatment represents the gold standard of therapy, chemo-radiotherapy, previously used as adjuvant treatment, has been more recently adopted with curative intent, leaving to surgery a salvage role only. When surgery is required it is advisable to reduce patients' trauma. The present study reports on a personal technique for minimally invasive pharyngo-laryngo-esophagectomy and reconstruction with the whole stomach. We use a laparoscopic approach for mobilization of the stomach, transhiatal esophageal dissection and to follow transhiatal gastric transposition to the neck combined to a cervicotomy to perform pharyngo-laryngectomy, proximal esophageal mobilization, and pharyngo-gastric anastomosis. We performed this technique on four patients with recurrent disease after initially curative primary chemo-radiotherapy. Mean operative time was 345 min (range: 300-384). There were no intraoperative complications. All patients were extubated immediately after the operation and were managed in postoperative care unit for a mean time of 10 days (range: 7-12). Enteral nutrition was begun on post-operative day (POD) 1. The nasogastric tube and drainages were removed on POD 11, and patients immediately started oral nutrition. One patient had a TIA (transient ischemic attack) on POD 2. All patients were discharged within 20 days (18-20). Initial experience with this minimally invasive technique in selected patients is encouraging because it seems to minimize postoperative complications and allows early rehabilitation.

Analysis of mesenchymal stem cells grown on a three-dimensional HYAFF 11-based prototype ligament scaffold

Ligaments are complex structures that maintain the mechanical stability of the joint. Healing of injured ligaments involves the interactions of different cell types, local cellular environment, and the use of devices. To gain new information on the complex interactions between mesenchymal stem cells (MSCs) and a specific hyaluronan-based prototype scaffold (HYAFF, useful for ligament tissue engineering, short time-course experiments were performed to analyze the proliferation, vitality, and phenotype of MSCs grown on the scaffold. MSC proliferation was analyzed using the MTT test, during the early time points (2, 4, 6, days). Viability was assessed using calcein/acetyloxymethylester immunofluorescence dye and confocal microscopy analysis. Hyaluronic acid receptor (CD44), typical matrix ligament proteins (collagen type I, type III, laminin, fibronectin, actin), and chondrogenic/osteogenic markers (collagen type II and bone sialoprotein) were evaluated by immunohistochemistry. Our data demonstrated that MSC growth and viability were cell density-dependent. MSCs completely wrapped the fibers of the scaffold, expressed CD44, collagen type I, type III, laminin, fibronectin, and actin, and were negative to collagen type II and bone sialoprotein. These data demonstrate that MSCs survive well in the hyaluronan-based prototype ligament scaffold, as assessed after 2 days from seeding, and express CD44, a receptor important for scaffold interaction, and proteins responsible for the functional characteristics of the ligaments.

103Rh NMR Chemical Shifts in Organometallic Complexes: A Combined Experimental and Density Functional Study

Experimental 103Rh NMR chemical shifts of mono- and binuclear rhodium(I) complexes containing s- or as-hydroindacenide and indacenediide bridging ligands with different ancillary ligands (1,5-cyclooctadiene, ethylene, carbonyl) are presented. A protocol, based on density functional theory calculations, was established to determine 103Rh NMR shielding constants in order to rationalise the effects of electronic and structural variations on the spectroscopic signal, and to gain insight into the efficiency of this computational method when applied to organometallic systems. Scalar and spin-orbit relativistic effects based on the ZORA (zeroth order regular approximation) level have been taken into account and discussed. A good agreement was found for model compounds over a wide range of chemical shifts of rhodium (approximately 10,000 ppm). This allowed us to discuss the experimental and calculated delta(103Rh) in larger complexes and to relate it to their electronic structure.

Interaction of volkensin with HeLa cells: binding, uptake, intracellular localization, degradation and exocytosis

Among two-chain ribosome-inactivating proteins (RIPs), volkensin is the most toxic to cells and animals, and is retrogradely axonally transported in the rat central nervous system, being an effective suicide transport agent. Here we studied the binding, endocytosis, intracellular routeing, degradation and exocytosis of this RIP. The interaction of volkensin with HeLa cells was compared to that of nigrin b, as an example of a type 2 RIP with low toxicity, and of ricin, as a reference toxin. Nigrin b and volkensin bound to cells with comparable affinity (approx. 10(-10) M) and had a similar number of binding sites (2 x 10(5)/cell), two-log lower than that reported for ricin. The cellular uptake of volkensin was lower than that reported for nigrin b and ricin. Confocal microscopy showed the rapid localization of volkensin in the Golgi stacks with a perinuclear localization similar to that of ricin, while nigrin b was distributed between cytoplasmic dots and the Golgi compartment. Consistently, brefeldin A, which disrupts the Golgi apparatus, protected cells from the inhibition of protein synthesis by volkensin or ricin, whereas it was ineffective in the case of nigrin b. Of the cell-released RIPs, 57% of volkensin and only 5% of ricin were active, whilst exocytosed nigrin b was totally inactive. Despite the low binding to, and uptake by, cells, the high cytotoxicity of volkensin may depend on (i) routeing to the Golgi apparatus, (ii) the low level of degradation, (iii) rapid recycling and (iv) the high percentage of active toxin remaining after exocytosis.

Activation of Cell Cycle Regulatory Proteins in the Apoptosis of Terminally Differentiated Oligodendrocytes

There is increasing evidence that proteins normally involved in the cell cycle play a role in the regulation of neuronal apoptotic death following various insults. However, it is not clear if the same mechanisms regulate cell death of oligodendrocytes as well. In this study, we investigated the mechanism of ceramide-induced apoptosis in primary rat oligodendrocytes. We show that ceramide treatment initiates a cascade of biochemical events involving cell cycle regulatory proteins. Although at the time of induction of cell death the oligodendrocytes are postmitotic, activation of c-myc and translocation of Cdc25A into the nucleus can be demonstrated. Of particular interest are the findings of the up-regulation of PCNA and down-regulation of p21WAF1/CIP1 protein, an inhibitor of cell-cycle progression. The current results show that activation of regulatory cell-cycle proteins at the oligodendrocytes G1-S checkpoint may constitute a crucial step of the death pathway of oligodendrocytes.

Targeting of the Akt/PKB kinase to the actin skeleton

Serine/threonine kinase Akt/PKB intracellular distribution undergoes rapid changes in response to agonists such as Platelet-derived growth factor (PDGF) or Insulin-like growth factor (IGF). The concept has recently emerged that Akt subcellular movements are facilitated by interaction with nonsubstrate ligands. Here we show that Akt is bound to the actin skeleton in in situ cytoskeletal matrix preparations from PDGF-treated Saos2 cells, suggesting an interaction between the two proteins. Indeed, by immunoprecipitation and subcellular fractioning, we demonstrate that endogenous Akt and actin physically interact. Using recombinant proteins in in vitro binding and overlay assays, we further demonstrate that Akt interacts with actin directly. Expression of Akt mutants strongly indicates that the N-terminal PH domain of Akt mediates this interaction. More important, we show that the partition between actin bound and unbound Akt is not constant, but is modulated by growth factor stimulation. In fact, PDGF treatment of serum-starved cells triggers an increase in the amount of Akt associated with the actin skeleton, concomitant with an increase in Akt phosphorylation. Conversely, expression of an Akt mutant in which both Ser473 and Thr308 have been mutated to alanine completely abrogates PDGF-induced binding. The small GTPases Rac1 and Cdc42 seem to facilitate actin binding, possibly increasing Akt phosphorylation.

Inositol-specific phospholipase C in low and fast proliferating hepatoma cell lines

Inositol lipid cycle, among the pletora of signalling events, is directly involved in cell growth. It is located both in the cytoplasm and in the nucleus. Disturbances may cause uncontrolled proliferation of the cell and ultimately cancer. The phosphatidyl inositol phospolipase C (PLC) is a key enzyme in the hydrolysis of polyphosphoinositides (PIs) and could be differently involved in the normal and pathological cell growth. We report immunochemical and immunocytochemical demonstrations that the PLC isoforms are present in both cytoplasmic and nuclear compartments of low and fast proliferating hepatoma cells. The PLC activity is increased in fast proliferating cells, in which PLC delta1 and to a greater extent PLC delta4 are more expressed at cytosolic level, suggesting an involvement of PI specific PLCs in the progression of cell cycle and in the control of cell proliferation and possibly of neoplastic cell growth.

Only pathologic complete response to neoadjuvant chemotherapy improves significantly the long term survival of patients with resectable esophageal squamous cell carcinoma: final report of a randomized, controlled trial of preoperative chemotherapy versus surgery alone

BACKGROUND

Surgery is the standard treatment for patients with resectable esophageal carcinoma, but the long term prognosis of these patients is unsatisfactory. Some randomized trials of preoperative chemotherapy suggest that the prognosis of patients who respond may be improved.

METHODS

This randomized, controlled trial compared patients with clinically resectable esophageal epidermoid carcinoma who underwent surgery alone (Arm A) with those who received preoperative chemotherapy (Arm B). Overall survival and the prognostic impact of major response to chemotherapy were analyzed. Forty-eight patients were enrolled in each arm. Chemotherapy consisted of two or three cycles of cisplatin (100 mg/m2 on Day 1) and 5- fluorouracil (1000 mg/m2 per day continuous infusion on Days 1-5). In both study arms, transthoracic esophagectomy plus two-field lymphadenectomy was performed. The two groups were comparable in terms of patient characteristics.

RESULTS

Forty-seven patients were evaluable in each arm. The curative resection rate was 74.4% (35 of 47 patients) in Arm A and 78.7% (37 of 47 patients) in Arm B. Treatment-related mortality was 4.2% in both arms. The response rate to preoperative chemotherapy was 40% (19 of 47 patients), including 6 patients (12.8%) who achieved a pathologic complete responses. Overall survival was not improved significantly. The 19 patients in Arm B who responded to chemotherapy and underwent curative resection had significantly better 3-year and 5-year survival rates (74% and 60%, respectively) compared with both nonresponders (24% and 12%, respectively; P = 0.0002) and patients in Arm A who underwent complete resection (46% and 26%, respectively; P = 0.01): Patients who achieved a pathologic complete response (P = 0.01), but not those who achieved a partial response (P = 0.2), had significantly improved survival.

CONCLUSIONS

Patients with resectable esophageal carcinoma who underwent preoperative chemotherapy and obtained a pathologic complete response had a significantly improved long term survival. Major efforts should be undertaken to identify patients before neoadjuvant treatments who are likely to respond.

Only pathologic complete response to neoadjuvant chemotherapy improves significantly the long term survival of patients with resectable esophageal squamous cell carcinoma: final report of a randomized, controlled trial of preoperative chemotherapy versus surgery alone

BACKGROUND

Surgery is the standard treatment for patients with resectable esophageal carcinoma, but the long term prognosis of these patients is unsatisfactory. Some randomized trials of preoperative chemotherapy suggest that the prognosis of patients who respond may be improved.

METHODS

This randomized, controlled trial compared patients with clinically resectable esophageal epidermoid carcinoma who underwent surgery alone (Arm A) with those who received preoperative chemotherapy (Arm B). Overall survival and the prognostic impact of major response to chemotherapy were analyzed. Forty-eight patients were enrolled in each arm. Chemotherapy consisted of two or three cycles of cisplatin (100 mg/m2 on Day 1) and 5- fluorouracil (1000 mg/m2 per day continuous infusion on Days 1-5). In both study arms, transthoracic esophagectomy plus two-field lymphadenectomy was performed. The two groups were comparable in terms of patient characteristics.

RESULTS

Forty-seven patients were evaluable in each arm. The curative resection rate was 74.4% (35 of 47 patients) in Arm A and 78.7% (37 of 47 patients) in Arm B. Treatment-related mortality was 4.2% in both arms. The response rate to preoperative chemotherapy was 40% (19 of 47 patients), including 6 patients (12.8%) who achieved a pathologic complete responses. Overall survival was not improved significantly. The 19 patients in Arm B who responded to chemotherapy and underwent curative resection had significantly better 3-year and 5-year survival rates (74% and 60%, respectively) compared with both nonresponders (24% and 12%, respectively; P = 0.0002) and patients in Arm A who underwent complete resection (46% and 26%, respectively; P = 0.01): Patients who achieved a pathologic complete response (P = 0.01), but not those who achieved a partial response (P = 0.2), had significantly improved survival.

CONCLUSIONS

Patients with resectable esophageal carcinoma who underwent preoperative chemotherapy and obtained a pathologic complete response had a significantly improved long term survival. Major efforts should be undertaken to identify patients before neoadjuvant treatments who are likely to respond.