Diseño y validación de la escala pronóstica cubana PREDICMED para estratificar el riesgo de mediastinitis postoperatoria / Design and validation of the Cuban prognostic scale PREDICMED to stratify the risk of postoperative mediastinitis

RESUMEN Introducción: La predicción de fenómenos en las ciencias médicas mediante escalas pronósticas constituye una herramienta valiosa en la actualidad y deben incluirse en el proceso de toma de decisiones. Pronosticar la mediastinitis postoperatoria permite disponer de recursos para su prevención. Objetivo: Construir una escala pronóstica para estratificar el riesgo de padecer mediastinitis postoperatoria. Método: Se realizó un estudio de casos y controles para los factores de riesgo de mediastinitis postoperatoria en el Cardiocentro Ernesto Guevara de Santa Clara, Cuba. Luego de la regresión logística se obtuvo el modelo y, a partir de este, se incluyeron y ponderaron los predictores para obtener la escala cubana pronóstica de mediastinitis postoperatoria: PREDICMED, que se validó por diversos métodos. Resultados: Esta escala se obtuvo con seis predictores y dos estratos de riesgo. Se analizó su rendimiento mediante ajuste, calibración y determinación de su poder discriminante, con buenos resultados. Se realizó validación interna por el método de división de datos y se comparó su capacidad en ambos subconjuntos (desarrollo y validación) sin diferencias. Se probó su buena validez de constructo, al no existir diferencias entre las probabilidades predichas y las observadas. También se analizó su validez de contenido mediante expertos. Por último, se determinó su validez de criterio al comparar con otra escala similar (MEDSCORE). PREDICMED presentó muy buena capacidad discriminatoria (área bajo la curva 0,962) y elevados valores de sensibilidad (84,62%) y especificidad (92,31%). Conclusiones: La escala pronóstica cubana PREDICMED, para estratificar el riesgo de mediastinitis postoperatoria, mostró buenos parámetros de validación y logró estratificar el riesgo en no alto y alto.

ABSTRACT Introduction: Phenomena prediction through prognostic scales is a valuable tool in medical sciences nowadays and it should be included in the decision-making process. Predicting postoperative mediastinitis allows to count on resources for its prevention. Objective: To build a prognostic scale to stratify the risk of suffering from postoperative mediastinitis. Method: A case-control study for the risk factors of postoperative mediastinitis was carried out at the Cardiocentro Ernesto Guevara from Santa Clara, Cuba. After the logistic regression, the model was obtained and from it, the predictors to obtain the Cuban prognostic scale of postoperative mediastinitis PREDICMED were included and weighted, which was validated through several methods. Results: This scale was obtained, counting on six predictors and two risk strata. Its performance was analyzed through adjustment, calibration and determination of its discriminating capacity, showing good results. Internal validation was carried out through the data division method and its capacity was compared in both subsets (development and validation) showing no differences. Its good construct validity was demonstrated, since there were no differences between the predicted and the observed probabilities. Its contents validity was also analyzed by experts. Finally, its criteria validity was determined when compared with another similar scale (Medscore). PREDICMED showed a very good discriminatory capacity (area under the curve 0.962) as well as high values of sensitivity (84.62%) and specificity (92.31%). Conclusions: The Cuban prognostic scale PREDICMED, to stratify the risk of postoperative mediastinitis showed good validation parameters and it was able to stratify the risk in not high and high.

Novel C,N-Cyclometalated Benzimidazole Ruthenium(II) and Iridium(III) Complexes as Antitumor and Antiangiogenic Agents: A Structure-Activity Relationship Study.

A series of novel C,N-cyclometalated benzimidazole ruthenium(II) and iridium(III) complexes of the types [(η(6)-p-cymene)RuCl(κ(2)-N,C-L)] and [(η(5)-C5Me5)IrCl(κ(2)-N,C-L)] (HL = methyl 1-butyl-2-arylbenzimidazolecarboxylate) with varying substituents (H, Me, F, CF3, MeO, NO2, and Ph) in the R4 position of the phenyl ring of 2-phenylbenzimidazole chelating ligand of the ruthenium (3a-g) and iridium complexes (4a-g) have been prepared. The cytotoxic activity of the new ruthenium(II) and iridium(III) compounds has been evaluated in a panel of cell lines (A2780, A2780cisR, A427, 5637, LCLC, SISO, and HT29) in order to investigate structure-activity relationships. Phenyl substitution at the R4 position shows increased potency in both Ru and Ir complexes (3g and 4g, respectively) as compared to their parent compounds (3a and 4a) in all cell lines. In general, ruthenium complexes are more active than the corresponding iridium complexes. The new ruthenium and iridium compounds increased caspase-3 activity in A2780 cells, as shown for 3a,d and 4a,d. Compound 4g is able to increase the production of ROS in A2780 cells. Furthermore, all the new compounds are able to overcome the cisplatin resistance in A2780cisR cells. In addition, some of the metal complexes effectively inhibit angiogenesis in the human umbilical vein endothelial cell line EA.hy926 at 0.5 µM, the ruthenium derivatives 3g (Ph) and 3d (CF3) being the best performers. QC calculations performed on some ruthenium model complexes showed only moderate or slight electron depletion at the phenyl ring of the C,N-cyclometalated ligand and the chlorine atom on increasing the electron withdrawing effect of the R substituent.

Pyrene-based dyad and triad leading to a reversible chemical and redox optical and magnetic switch.

Two new pyrene-polychlorotriphenylmethyl (PTM) dyads and triads have been synthesized and characterized by optical, magnetic, and electrochemical methods. The interplay between the different electronic states of the PTM moiety in the dyads and triads and the optical and magnetic properties of the molecules have been studied. The electronic spectra of the radicals 5(.) and 6(.) show the intramolecular charge-transfer transition at around 700 nm due to the acceptor character of the PTM radical. In the diamagnetic protonated derivatives 3 and 4 the fluorescence due to the pyrene is maintained, whereas in the radicals 5(.) and 6(.) and the corresponding anions 5(-) and 6(-) there is a clear quenching of the fluorescence, which is more efficient in the case of radicals. The redox activity of PTM radicals that are easily reduced to the corresponding carbanion has been exploited to fabricate electrochemical switches with optical and magnetic response.

Tris(triazole) tripodal receptors as selective probes for citrate anion recognition and multichannel transition and heavy metal cation sensing.

The three-armed pyrenyl-triazole receptor 1 behaves as a highly selective fluorescent molecular sensor for citrate anions over similar carboxylates such as malate or tartrate. In addition, this receptor senses Cu(2+) cations through absorption and emission channels even in the presence of Hg(2+) metal cations. The related three-armed ferrocenyl-triazole receptor 2 behaves as a highly selective dual (redox and chromogenic) chemosensor molecule for Pb(2+) metal cations.

Nitrogen-rich multinuclear ferrocenophanes as multichannel chemosensor molecules for transition and heavy-metal cations.

[m.n] Multinuclear ferrocenophanes prepared by aza-Wittig reaction of bisiminophosphoranes derived from 1,1'-diazidoferrocene and isophthaladelhyde or 2,5-diformylthiophene, behave as efficient electrochemical and chromogenic chemosensor molecules for Zn2+, Pb2+, and Hg2+ metal cations. Whereas the OSWV of receptor 3, bearing two m-phenylene units in the bridges, display one oxidation peak, receptor 4 incorporating two thiophene rings in the bridges, exhibits two well-separated oxidation peaks. In both receptors only the addition of Zn2+, Pb2+, and Hg2+ metal cations induced a remarkable anodic shift of ferrocene/ferrocenium redox couple. Likewise, in the absorption spectra of these receptors the low energy band is red-shifted by Δλ = 165 - 209 nm, and these changes promoted a significant color changes which could be used for the naked eye detection of these metal cations. The coordination modes for two representative cases were unveiled by DFT calculations that show an unsual coordination in the [42Pb]2+ complex with the Pb2+ cation in a distorted cubic N4S4 donor cage.

Oxaphosphirane-borane complexes: ring strain and migratory insertion/ring-opening reactions.

DFT-based HSAB-related parameters predict most favorable P- versus O-complexation of parent oxaphosphirane (1) with a variety of borane reagents BR3 (2). In general, strong P-B bonds are formed, especially for R: H (3a), Cl (3d), and C6F5 (3g), in agreement with large dissociation energies, whereas O-B bonds are usually weaker. A remarkable increase in ring strain is observed upon P-complexation of phosphirane or oxaphosphiranes, especially in the case of 3g and 3d, whereas a moderate decrease occurs in the case of O-complexation for both oxirane and oxaphosphiranes. Stronger P-B bonds also correlate with larger charge transfer from the oxaphosphirane to the borane units. This in turn increases electron density at the boron center and weakens all B-R bonds, thus enabling migratory insertion/ring-opening reactions in which a substituent from the borate center shifts to a ring atom; these reactions are additionally driven by release of the high ring strain of P-complexes 3.

A novel N,P,C cage complex formed by rearrangement of a tricyclic phosphirane complex: on the importance of non-covalent interactions.

The reaction of Li/Cl P-CPh3 phosphinidenoid tungsten(0) complex 2 with dimethylcyanamide afforded tricyclic phosphirane complex 4, an unprecedented rearrangement of which led to the novel N,P,C cage complex 6. On the basis of DFT calculations, formation and intramolecular [3+2] cycloaddition of the transient nitrilium phosphane ylide complex 3 to a phenyl ring of the triphenylmethyl substituent to give 4 is proposed. Furthermore, theoretical evidence for terminal N-amidinophosphinidene complex 7, formed by [2+1] cycloelimination from 4, is provided, and the role of the electronic structure and non-covalent interactions of intermediate 7 discussed.

Multifunctional Benzothiadiazole-Based Small Molecules Displaying Solvatochromism and Sensing Properties toward Nitroarenes, Anions, and Cations.

Aryl or heteroaryl 5-substituted imidazo-benzothiadiazole derivatives were synthesized and shown to display remarkable solvatofluorochromism and selectively sense mercury(II) cations, acetate anions, and nitroaromatic derivatives, with discrimination between p-nitrophenol and picric acid. These novel sensors are of importance these days, as the detection of explosives is a high priority in issues of national security and environmental protection. To determine the ion binding properties of the sensors, their absorption and fluorescence emission spectra upon binding different cations and anions were compared. Significant shifts in the spectra were only observed for mercury(II) and acetate. The binding of these two ions was further studied using (1)H NMR. The binding properties of different nitroaromatic compounds were also determined, and the results showed the importance of the presence of a phenol group in the guest molecule. Specifically, the two sensors were shown to discriminate between p-nitrophenol and picric acid. Finally, the mechanism of fluorescence quenching upon addition of nitrophenols was determined by computational methods.

Bis(carbazolyl)ureas as selective receptors for the recognition of hydrogenpyrophosphate in aqueous media.

Recognition properties of the novel bis(carbazole) tris-ureidic-based receptors 1 and 2 toward different anions have been studied by (1)H NMR and absorption and emission spectroscopy, as well as by DFT calculations. Receptor 1, in which the two urea-functionalized arms are decorated with p-nitrophenyl rings, behaves as a highly selective chromogenic molecular probe for hydrogenpyrophosphate anion in a competitive medium (acetonitrile/water, 70/30). Receptor 2, bearing two urea arms decorated with photoactive pyrenyl rings, acts as a highly selective fluorescent molecular probe for hydrogenpyrophosphate anion in either acetonitrile or an aqueous mixture (acetonitrile/water, 85/15). Receptor 2 exhibits a dual monomer-excimer emission spectrum and undergoes a remarked ratiometry in acetonitrile in the presence of hydrogenpyrophosphate: the excimer band disappears, whereas the monomer band is slightly increased. However, in the aqueous mixture, a strong increase of the excimer emission band was observed, while the monomer emission bands remained almost unaffected. The resulting binding modes and spectroscopic features are explained by suitable structures of model complexes for both receptors. In such complexes, a peripheral cooperative effect was found, alleviating the excess of negative charge in the guest toward the outer surface of the host, as well as the required enlargement on its internal cavity.

A densely decorated disubstituted ferrocene as an ion-pair recognition receptor.

A functionalized 1,1'-disubstituted ferrocene acts as an electro-optical ion-pair receptor for Mg(2+), Ca(2+), Cd(2+), and Zn(2+) cations in the presence of a co-bound H2PO4(-) anion, through perturbation of the redox potential of the ferrocene unit, enhancement of the fluorescence and a noticeable colour change.

New steroidal 7-azaindole platinum(II) antitumor complexes.

Two new steroidal 7-azaindole-based N-donor ligands 17-α-[7-azaindole-5-ethynyl]-17-ß-testosterone (ET-Haza) (1) and 17-α-[7-azaindole-5-ethynyl]-19-nortestosterone (LEV-Haza) (2), and two new DNA damaging warheads with an enhanced lipophilicity [Pt(dmba)Cl(L)] (dmba=N,N-dimethylbenzylamine-κN,κC; L=ET-Haza (3) and LEV-Haza (4)) have been prepared and characterized. Values of IC50 were calculated for complexes 3 and 4 against a panel of human tumor cell lines representative of ovarian (A2780 and A2780cis) and breast cancers (T47D). At 48 h of incubation time 3 and 4 showed very low resistance factors (RF of 1) against an A2780 cell line which has acquired resistance to cisplatin, IC50 values of the new complexes towards normal human LLC-PK1 renal cells at 48 h being about double than that of cisplatin. 3 and 4 are able to react with 9-ethylguanine (9-EtG) yielding the corresponding monoadduct [Pt(dmba)(L)(9-EtG)](+) derivatives as followed by ESI-MS. Compound 3 interacts mainly with double-stranded (DS) oligonucleotides as shown by analysis with ESI-TOF-MS, being also able to displace ethidium bromide (EB) from DNA, as observed by an electrophoretic mobility study. 3 and 4 are good cathepsin B inhibitors. Theoretical calculations at the COSMO(CHCl3)/B3LYP-D/def2-TZVPPecp//B3LYP-D/def2-TZVPecp level and energy evaluations at the COSMO(CHCl3)/PWPB95-D3/def2-TZVPPecp level of theory on compound 4 and model systems have been done.

Reaction of Li/Cl phosphinidenoid complexes with a phosphite substituted ketone: access to complexes with a novel mixed-valence polycyclic P,C-ligand system.

Reaction of Li/Cl phosphinidenoid pentacarbonyltungsten(0) complexes 2a,b (R = CH(SiMe3)2, Cp*) with bifunctional phosphite-substituted ketone 3 yielded tungsten complexes 4a,b having a novel mixed-valence polycyclic P,C-cage ligand with a P­P bond. DFT calculations provide insight into an unusual product formation pathway.

Synthesis and DFT calculations of spirooxaphosphirane complexes.

In situ formed Li/Cl phosphinidenoid complexes [Li(12-crown-4)][M(CO)5(ClPC5Me5)] 3a-c (M = Cr, Mo, W) reacted with cyclobutanone (4), cyclopentanone (5) and cyclohexanone (6) in Et2O to yield the first P-C5Me5 substituted C(3)-spirofused oxaphosphirane complexes 7a-c, 8a and 9a,a'. In the case of cyclopentanone and 1a the outcome of the reaction in THF was different: here the formation of 8a along with (anionic) phosphinoate complexes 14a and 15a was observed, the latter possess an unusual ring-opened oxaphosphirane and 2-cyclopentylidenecyclopentanone as co-ligands to the lithium cation. NMR, IR and MS data as well as single-crystal X-ray structures in the case of 7a-c, 8a, 9a and 15a are reported. DFT calculations on the parent 1-oxa-2-phosphaspiro[2.n]alkane pentacarbonylchromium(0) complexes 10 (a: n = 2; b: n = 3; c: n = 4; d: n = 5) revealed that both ring strain energies and G(r) values decrease significantly as the spiroring size increases. This is caused by an increase in the exocyclic α bond angle at the oxaphosphirane C(3) atom, hence decreasing the s-character of the corresponding orbitals involved in endocyclic bonds at C(3) and thus becoming better suited for accommodation of small ring angles.

Synthesis and reactions of the first room temperature stable Li/Cl phosphinidenoid complex.

P-Trityl substituted Li/Cl phosphinidenoid tungsten(0) complex (OC)5W{Ph3CP(Li/12-crown-4)Cl} (3) was prepared via chlorine/lithium exchange in complex (OC)5W{Ph3CPCl2} (2) using (t)BuLi in the presence of 12-crown-4 in tetrahydrofuran (THF) at low temperature; complex 3 possesses significantly increased thermal stability in contrast to previously reported analogue derivatives. Terminal phosphinidene-like reactivity of 3 was used in reactions with benzaldehyde and isopropyl alcohol as oxaphosphirane complex (OC)5W{Ph3CPC(Ph)O} (5) and phosphinite complex (OC)5W{Ph3CP(H)O(i)Pr} (6) were obtained selectively. Reaction of 3 with phosgene allowed to obtain the first kinetically stabilized chloroformylphosphane complex (OC)5W{Ph3CP(Cl)C(O)Cl} (4). Density functional theory (DFT) calculations revealed remarkable differences in the degree of P-Li bond dissociation 3a-d: using a continuum model 3 displays a covalent character of P-Li bond (COSMO (THF)) (a), which becomes elongated if 12-crown-4 is coordinated to lithium (b) and is cleaved if a dimethylether unit is additionally coordinated to lithium (c). A similar result was obtained for the case of 3(thf)4 in which also a solvent-separated ion pair structure is present (d). All products were unambiguously characterized by various spectroscopic means and, in the case of 2 and 4-6, by single-crystal X-ray diffraction analysis. In all structures very long P-C bonds were determined being in the range from 1.896 to 1.955 Å.

Ion pair recognition receptor based on an unsymmetrically 1,1'-disubstituted ferrocene-triazole derivative.

The ferrocene-triazole derivative 4, available from 1,1'-bis(diazido)ferrocene by sequential functionalization through click-type chemistry and the Staudinger reaction, is elaborated as a lab-on-a-molecule for the selective sensing of HP(2)O(7)(3-) and Hg(2+). Receptor 4 behaves as a ratiometric fluorescent probe for HP(2)O(7)(3-) with a good selectivity over other anions, whereas in the presence of Hg(2+) it modifies the fluorescent emission of the pyrene unit, acting as a selective on-off fluorescent sensor for Hg(2+) with a low detection limit. The most salient feature of compound 4 is its behavior as an excellent electrooptical ion pair recognition receptor able to simultaneously recognize Pb(2+) cations in the presence of HP(2)O(7)(3-) anion through multichannel perturbations of the redox potential of the ferrocene unit, the emission spectrum, and a noticeable color change from yellow to green.

Exocyclic bond cleavage in oxaphosphirane complexes?

A first computational insight into the intrinsic strength of exocyclic bonds to phosphorus in oxaphosphirane κP-pentacarbonylmetal(0) complexes 1a-f (M=Cr, Mo) is provided using a set of P-R derivatives (R=Me, tBu, CPh(3)). Whereas homolytic cleavage of the exocyclic P-R bond was found to be always unfavored (for neutral complexes), heterolytic cleavage leading to a carbocation R(+) moiety and the oxaphosphiranide complex 2(-) constitutes the lowest-energy process, especially if R is bulky and can stabilize the positive charge, that is, triphenylmethyl (trityl), efficiently. The energies required for P-M bond cleavage are about 30 kcal mol(-1), and decrease with the increasing bulk of the R substituent (from Me to trityl) and ongoing from Cr to Mo. The reactivities of complexes 1a-f towards oxidative and reductive single electron transfer (SET) reactions were analyzed using the facile variation of bond-strength-related descriptors (VBSD) methodology, thus enabling the design of synthetically useful strategies addressing decomplexation and P-functionalization. Reductive SET reactions with sodium naphthalenides enable selective P-M bond cleavage (i.e., decomplexation) for the case of P-Me and P-tBu substitution, whereas reductive P-R bond cleavage is favored in the case of the P-trityl complexes 1c,f, and results in the formation of the (anionic) oxaphosphiranide complex 2(-), which may be regarded as a potential key intermediate for further P-functionalization.

Novel C,N-chelate rhodium(III) and iridium(III) antitumor complexes incorporating a lipophilic steroidal conjugate and their interaction with DNA.

The novel steroidal conjugates [M(η(5)-C(5)Me(5))Cl(LEV-ppy)] (M = Rh (1) and Ir (2)) bearing the lipophilic levonorgestrel group 17-α-[2-phenylpyridyl-4-ethynyl]-19-nortestosterone (LEV-ppy), where the chelating ligand is N and C-bound, have been prepared and characterized. Both compounds are more active than cisplatin (about 6-fold) in T47D (breast cancer) at 48 h incubation time. On the other hand, very low resistance factors (RF) of 1 and 2 in A2780cisR (cisplatin-resistant ovarian carcinoma) at 48 h were observed (RF = 0.9 and 1.1, respectively). The iridium steroidal compound 2 is twice as active as the non-steroidal analogue 2', whose promising anticancer activity has recently been reported by Sadler. Theoretical DFT calculations on complexes 1 and 2 at the B3LYP-D/def2-TZVP-ecp level of theory show that the strongest bond to the metal atom is the η(5)-interaction to the Cp* ligand and that both of them feature a rather strong metal-chlorine bond. The new steroidal conjugates 1 and 2 are able to bind to DNA according to Hoechst 33258 displacement experiments and ESI-TOF MS spectrometry studies. Complexes 1 and 2 are also cathepsin B inhibitors, an enzyme implicated in a number of cancer related events.

Single electron transfer-mediated selective endo- and exocyclic bond cleavage processes in azaphosphiridine chromium(0) complexes: a computational study.

Azaphosphiridines κP pentacarbonylchromium(0) complexes 2a,b (2a: R = H; 2b: R = Me) exhibit an average ring strain ranging from 24.2 to 25.7 kcal mol(-1) as obtained from homodesmotic reactions at the LPNO-NCEPA1/def2-TZVPP//BP86/def2-TZVP level. Parent azaphosphiridine chromium complex 1 is more stable than the ylidic P-iminiumphosphanide chromium complex isomer 6, which is obtained from (formal) endocyclic P-C bond cleavage. Computational evidence is provided for an insertion of carbon monoxide into the P-N bond of 1 to form 1,3-azaphosphetidin-2-one chromium complex 11, as the reaction was exergonic by -15.1 kcal mol(-1). The VBSD (variation of bond strength descriptors) methodology unveiled that SET (single electron transfer) oxidation of trimethyl-azaphosphiridine chromium complex 2b results in selective endocyclic P-C bond cleavage to afford the trimethyl-iminiumphosphanyl radical cation complex 13(•+). SET reduction of a wide variety of differently P-substituted azaphosphiridine complex derivatives (2a: R = H; 2b: R = Me; 2c: R = Cp; 2d: R = Cp*; 2e: R = CHTms(2); 2f: R = CMe(3); 2g: R = CMe(2)Ph; 2h: R = CMePh(2); 2j: R = Ph; 2k: R = C(6)F(5); Cp*: pentamethylcyclopentadienyl; Tms: trimethylsilyl) lead to selective decomplexation and thus to the corresponding unligated azaphosphiridines 14. Only in case of the P-trityl substituted azaphosphiridine complexes 2i does the SET reduction preferably cleave the exocyclic P-C bond thus affording azaphosphiridinide complex 12(-) and the triphenylmethyl radical.

Indolocarbazole-based ligands for ladder-type four-coordinate boron complexes.

A novel class of π-conjugated systems, which combine the indolo[3,2-b]carbazole unit with the formation of four-coordinate boron complexes, is presented. The resulting conjugated compounds have a double-laddered structure that provides interesting optical and electrochemical properties. The wide absorption range, covering most of the visible spectrum, along with the narrowing of the HOMO-LUMO energy gap, due to the presence of diphenylboryl centers, reinforces the potential of these molecules within the area of organic electronics.

Multichannel HSO4- recognition promoted by a bound cation within a ferrocene-based ion pair receptor.

A ferrocene-based ion pair receptor is shown only to recognise HSO(4)(-) anions in the presence of a cobound Pb(2+) or Zn(2+) cation guest species through a perturbation of the redox potential of the ferrocene unit and a remarkable enhancement of the fluorescence.