Adriano Berton

Changes in Fluid Compartments and Body Composition in Obese Women after Weight Loss Induced by Gastric Banding

Background/Aims: Surgical gastric banding procedures induce considerable and rapid weight losses in obese subjects. Nevertheless changes in lean mass and body fluids following these surgical treatments are not well known. Methods: We studied 6 obese women aged 38–42 years, before, and 8 and 24 weeks after laparoscopic adjustable silicone gastric banding (LAP-BANDTM). Fat-free mass (FFM) and fat mass (FM) were investigated using dual energy X-ray absorptiometry (DEXA), while total body water (TBW) and extracellular water (ECW) were assessed by dilution methods. Results: The subjects showed a total weight loss of 16% of initial weight; the weight reduction was greater during the first 8 weeks. FFM decrease after 24 weeks was very limited and represented only 14% of the weight loss. The mean FFM changes per week were similar in the two periods of observation (0–8 and 8–24 weeks after LAP-BAND). TBW showed a global reduction of 2.2 ± 1.8 litres mainly due to a decline in intracellular water (ICW), while ECW remained constant during weight loss. As a consequence, the ECW/ICW ratio increased after LAP-BAND. Conclusion: LAP-BAND seems to achieve satisfactory weight losses while sparing FFM and causing only mild body fluid alterations.

Preparation and reactions of palladium(II) complexes with C2-bonded heteroaromatic ligands trans[PdCl(RN)(PPh3)2] (RN = 2-pyridyl, 2-pirazyl, 2-pyrimidyl group). A new reaction pathway in the insertion of isocyanides into the Pdc bond of trans-[PdXR(L)2] compounds

Abstract The complexes trans -[PdCl(R N )(PPh 3 ) 2 ] (I) [R N = 2-pyridyl (2-Py), 2-pyrazyl (2-pyz), 2-pyrimidyl (2-pym) group] have been prepared in high yield by deprotonation with NEt 3 of the corresponding cationic compounds trans [PdCl(R N H) (PPh 3 ) 2 ] + (R N H = N -protonated C 2 -heteroaromatic ligand) in the presence of an excess of PPh 3 . In chlorinated solvents, complexes I undergo a slow reversible dimerization into the binuclear derivatives [PdCl(μ-R N )(PPh 3 )] 2 (II) (μ-R N = C 2 , N 1 -bridging ligand). From the 31 P NMR spectra in 1,2-dichloroethane the following dissociation constants were obtained: 1.9 mol 1 −1 (R N = 2-py), 5.1 × 10 −2 (2-pym), 6.6 × 10 −3 (2-pyz). The dimerization becomes fast and quantitative if the PPh 3 , involved in the equilibrium is removed by oxidation or by reaction with [PdCl(η 3 -2-MeC 3 H 4 )] 2 . Only the 2-pyridyl complex Ia reacts (slowly) with CO yielding the migratory insertion product trans -[PdCl{C(2-py)O}(PPh 3 ) 2 ], together with the dimer IIa. All the complexes I undergo migratory insertion of t-butylisocyanide with formation of trans -[PdCl{C(R N ) = NCMe 3 }(PPh 3 ) 2 ]] at rates which depend on the heterocyclic group (R N = 2-py > 2-pyz ⪢ 2-pym). The reaction of the 2-pyrazyl complex Ib with CNCMe 3 has been studied in detail by conductivity measurements and by IR and 31 P NMR spectroscopy. The data suggest a complex mechanism in which insertion occurs through rearrangement of a four-coordinate intermediate [PdCl(2-pyz)(CNCMe 3 )(PPh 3 )], and through interaction of a cationic intermediate trans -[Pd(2-pyz)(CNCMe 3 )(PPh 3 ) 2 ] + (Vb) with Cl − and with the free isocyanide of the initial equilibria. The occurrence of the latter reactions is confirmed by independent experiments in which the cationic complex Vb (isolated as perchlorate salt) is treated with an equimolar amount of [AsPh 4 ]Cl or CNCMe 3 . The isocyanide-promoted insertion step represents a new mechanistic pathway for isocyanide insertion into the PdC bond of trans -[PdXR(L) 2 ] complexes.

Preparation and reactions of 2-pyridylplatinum(II) complexes [PtCl(C5H4N-C2)(L)2] (L = tertiary phosphine) Compounds with a markedly nucleophilic pyridine nitrogen atom

Abstract The 2-pyridyl complex trans -[PtCl(C 5 H 4 N- C 2 )(PPh 3 ) 2 ] (I) can be prepared in high yield by oxidative addition of 2-chloropyridine to [Pt(PPh 3 ) 4 ]. The reaction of I with 1,2-bis(diphenylphosphino)ethane yields the cis derivative [PtCl(C 4 5 H 4 N- C 2 )(dppe)] (II). In polar solvents, the latter rearranges to the binuclear cationic complex [Pt(μ-C 5 H 4 N- C 2 , N )(dppe)] 2 Cl 2 . The reaction of I with [PdCl(η 3 -2-MeC 3 H 4 )] 2 (1/0.5 molar ratio) gives the products [PtCl(μ-C 5 H 4 N- C 2 , N )(PPh 3 )] 2 (IV) and [PdCl(η 3 -2-MeC 3 H 4 )(PPh 3 )]. 31 P NMR monitoring of the reaction suggests that PPh 3 transfer occurs in a binuclear platinum/palladium intermediate with a bridging 2-pyridyl ligand, and leads initially to a chloride-bridged species [Pt(μ-Cl)(C 5 H 4 -N- C 2 )(PPh 3 )] 2 , which then rearranges to the more stable compound IV. Complexes I and II are readly N -protonated by HCl or HClO 4 to give the cationic derivatives [PtCl(C 5 H 5 N- C 2 )(PPh 3 ) 2 ] + and [PtCl(C 5 H 5 N- C 2 )(dppe)] + . In dichloromethane or 1,2-dichloroethane, the terminal 2-pyridyl group of I and II is slowly N -alkylated by the solvent to give [PtCl{l-R)C 5 H 4 n- C 2 }(PPh 3 ) 2 ]Cl and [PtCl(l-R)C 5 H 4 N- C 2 (dppe)]Cl (R  CH 2 Cl or CH 2 CH 2 Cl).

Phenylation of cationic allyl palladium(II) complexes by tetraphenylborate. Synthesis of α-diimine olefin palladium(0) complexes and mechanistic aspects

The cationic allyl complexes [Pd(η3-2-R1C3H4)(N–N′)]+(N–N′=α-diimine ligand; R1= H or Me) react with BPh4– in the presence of activated olefins to give [Pd(η2-olefin)(N–N′)](olefin = fumaronitrile, dimethyl fumarate or maleic anhydride) and PhCh2C(R1)CH2. The palladium(0) derivatives can be isolated in good yield and have been characterized by elemental analysis, molecular weight measurements and standard spectroscopic techniques. The reaction rates increase with increasing π-accepting ability of the α-diimine, with decreasing steric requirements of the imino carbon substituents and with decreasing stability towards palladium–nitrogen bond breaking in the parent cationic compounds. The rates also increase with decreasing relative permittivity and co-ordinating properties of the solvent. Kinetic measurements in aqueous (2% v/v) methanol provide pseudo-first-order rate constants that are independent of both BPh4– and olefin concentrations. This has been interpreted on the basis of extensive ion pairing between the cationic substrate and the BPh4– anion, followed by rate-determining phenyl transfer to the palladium centre and fast reductive elimination of allylbenzenes.

N-protonated 2-pyridylnickel(II) complexes insertion of isocyanides into the nickel2-pyridyl bond

The reaction of the binuclear complex [NiCl(μ-2-py)(PPh3)]2 (μ-2-py = μ-C5H4N-C2,N) with the phosphines L (L = PPh3, PMePh2, PMe2Ph or PEt3) or dppe (= 1,2-bis(diphenylphosphino)ethane) in the presence of HClO4 yields the N-protonated 2-pyridyl derivatives trans-[NiCl(2-pyH)(L)2]ClO4 or [NiCl(2-pyH)(dppe)] ClO4 (2-pyH = C5H5N-C2) with a square-planar coordination around the nickel(II) center. These products are largely associated through hydrogen bonding between the NH group and the perchlorate anion, both in the solid and in chlorinated solvents. The configuration in solution has been studied by 1H and 31P NMR spectroscopy. In the complex trans-[NiCl(2-pyH)(PMe2Ph)2]ClO4, the planar 2-pyH ligand is oriented perpendicularly to the coordination plane, with restricted rotation about the NiC2 bond. The reaction of rans-[NiCl(2-pyH)(PMePh2)2]ClO4 with CNC6H4OMe-p and then with NEt3 yields the unstable compound trans-[NiCl{C(2-py)NC6H4OMe-p}(PMePh2)2] through a fast migratory insertion of the isocyanide into the nickel2-pyridyl bond. This product can be isolated and characterized only when the imino(2-pyridyl)methyl group is σ,σ′-N,N′-chelated to ZnCl2.

Reaction of Pd(η3-C3H5)2 with cyano-olefins; reductive coupling of allyl groups in the presence of triphenylphosphine

Abstract Pd(η3-3H5)2 reacts with tetracyanoethylene (TCNE) to give a 1/1 adduct identified as Pd(η3-C3H5)(η1-C3H5)(TCNE) on the basis of spectroscopic evidence and its behaviour in solution. A similar re The complex Pd(η3-C3H5)(η1-C3H5)(TCNE) reacts with triphenylphosphine to give 1,5-hexadiene and Pd(PPh3)2(TCNE); a mechanism for this reaction is pro-posed on the basis of low temperature 1H and 31P NMR spectroscopy study of the soluti during the reaction. The mechanisms are compared with those for the Pt(η3-C3H5) system.

Reliability of bioelectrical impedance methods in detecting body fluids in elderly patients with congestive heart failure.

Objective. To investigate the reliability of bioelectrical impedance analysis (BIA) in estimating total body water (TBW) and extracellular water (ECW) in elderly patients suffering from congestive heart failure (CHF). Material and methods. In 72 elderly subjects, 34 with CHF (aged 83.9±6.9 years) and 38 healthy controls (78.7±7.5 years), TBW and ECW values were assessed using dilution methods, and bioelectrical variables were measured using single frequency BIA (SF‐BIA) at 1 and 50 kHz, and bioelectrical spectroscopy (BIS). Results. In CHF patients, Ht2/R1 correlated weakly with TBW (r = 0.56) and ECW (0.47). In both healthy controls and CHF patients, TBW correlated strongly with Ht2/R50, Ht2/R0, Ht2/R∞ and Ht2/Zc. Using multiple regression analysis and the Bland–Altmann approach, SF‐BIA at 50 kHz and BIS proved similar in predicting TBW for both the explained variance (R2∼0.89) and the limits of agreement. In all subjects, ECW was estimated best by including height, weight and Ht2/R0 (R2 0.75) or Ht2/Zc (R2 0.77) in multivariate models, while SF‐BIA at 50 kHz did not explain more than 71 % of ECW variability. The SEE % was nonetheless about twice the SEE % for estimating TBW. Conclusions. SF‐BIA at 1 kHz is unreliable in predicting body fluids in elderly people with CHF. SF‐BIA at 50 kHz and BIS are useful for estimating TBW in healthy elderly people and in cases of water imbalance, but both methods are less reliable in estimating ECW, particularly in conditions of fluid overload.

COORDINATION PROPERTIES OF IMINO(2-PYRIDYL)METHYLPALLADIUM(II) COMPOUNDS - PREPARATION AND THERMAL REARRANGEMENT OF BINUCLEAR ADDUCTS WITH PALLADIUM(II) AND PLATINUM(II) CHLORIDES

Abstract The imino(2-pyridyl)methylpalladium(II) compound py-2-C(R′)NR (R = C 6 H 4 OMe-p, R′ = trans-PdCl(PPh 3 ) 2 ) reacts with [PdCl 2 (CH 2 CHPh)] 2 , [PdCl 2 - (NCMe) 2 ], and K[PtCl 3 (CH 2 CH 2 )] to give binuclear complexes [MCl 2 {py-2- C(R′)NR}] (M = Pd, Pt), in which the α-diimino group acts as a chelating bidentate ligand. In hot 1,2-dichloroethane, these complexes undergo a PPh 3 and chloride ligand exchange at rates which depend markedly on the metal M (Pd ⪢ Pt), to yield the new derivatives [MCl(PPh 3 ){py-2-C(cis-PdCl 2 (PPh 3 ))NR}]. The ligand exchange is followed by a much slower decomposition to [MCl 2 (PPh 3 ) 2 ]. Labile intermediates of the same type, [MCl(PPh 3 ){RNC(cis-PdCl 2 (PPh 3 ))C(R″)NR}], are formed also in the thermal decomposition of [MCl 2 {RNC(R′)C(R″)NR}] (R = C 6 H 4 OMe-p; R′ = trans-PdCl(PPh 3 ) 2 ; R″ = H, Me). The reactions of the dimethyldithiocarbamate derivative py-2-C(Pd(dmtc)(PPh 3 ))NR (R = C 6 H 4 OMe- p) with K[PtCl 3 (CH 2 CH 2 )] and [PdCl 2 (NCMe) 2 ] yield the different products [PtCl 2 py-2-C(Pd(dmtc)(PPh 3 ))NR] and [Pd(dmtc)py-2-C(cis-PdCl 2 (PPh 3 ))NR], respectively.

Witting reaction on carbonyl-containing cyclotriphosphazenes: the case of hexakis(4-formylphenoxy)cyclophosphazene

Abstract The Wittig reaction between hexakis(4-formylphenoxy) cyclophosphazene [NP(O-C 6 H 4 - p -CHO) 2 ] 3 ( 1 ) and several stabilized phosphonium ylides leads to the preparation of double bond-containing cyclophosphazenes. All the characterization data obtained for the synthesized compounds indicated that the cyclophosphazene ring is not involved in this reaction, the only reactive functions being the aldehydic groups in the side substituents of 1 . These products proved to be promising materials in further functionalization studies and may open interesting perspectives in the case of the corresponding phosphazene high polymers.

Total body water and extracellular water measurements through in vivo dilution of D2O and bromide as tracers

Large interest is into the determination of body fluids because of changes in body water in a wide variety of physio- logical and pathological conditions. Here methods based on dilution of tracers, are reported, for the extracellular water (ECW) and total body water (TBW) determinations on the same sample. As for ECW, bromide is used as tracer and its concentration is determined by energy dispersive X-ray spectrometry; while as for TBW, D2O is used as tracer and HOD is determined by FT IR. Both methods represent significant improvements with respect the procedures described in the literature in terms of availability, reproducibility and accuracy.