Fabry-Stroke Italian Registry (FSIR): a nationwide, prospective, observational study about incidence and characteristics of Fabry-related stroke in young-adults. Presentation of the study protocol.

BACKGROUND: TIA and stroke, both ischemic and hemorrhagic, may complicate Fabry disease at young-adult age and be the first manifestation that comes to the clinician's attention. No definite indications have yet been elaborated to guide neurologists in Fabry disease diagnostics. In current practice, it is usually sought in case of cryptogenic strokes (while Fabry-related strokes can also occur by classical pathogenic mechanisms) or through screening programs in young cerebrovascular populations. Data on recurrence and secondary prevention of Fabry's stroke are scanty. METHODS: The study had a prospective observational design involving 33 Italian neurological Stroke Units. Considering the incidence of TIA/stroke in the European population aged < 60 years and the frequency of Fabry disease in this category (as foreseen by a pilot study held at the Careggi University-Hospital, Florence), we planned to screen for Fabry disease a total of 1740 < 60-year-old individuals hospitalized for TIA, ischemic, or hemorrhagic stroke. We investigated TIA and stroke pathogenesis through internationally validated scales and we gathered information on possible early signs of Fabry disease among all cerebrovascular patients. Every patient was tested for Fabry disease through dried blood spot analysis. Patients who received Fabry disease diagnosis underwent a 12-month follow-up to monitor stroke recurrence and multi-system progression after the cerebrovascular event. DISCUSSION: The potential implications of this study are as follows: (i) to add information about the yield of systematic screening for Fabry disease in a prospective large cohort of acute cerebrovascular patients; (ii) to deepen knowledge of clinical, pathophysiological, and prognostic characteristics of Fabry-related stroke.

Blood-brain barrier leakage and hemorrhagic transformation: The Reperfusion Injury in Ischemic StroKe (RISK) study.

BACKGROUND AND PURPOSE: In patients with acute ischemic stroke treated with reperfusion therapy we aimed to evaluate whether pretreatment blood-brain barrier (BBB) leakage is associated with subsequent hemorrhagic transformation (HT). METHODS: We prospectively screened patients with acute ischemic stroke treated with intravenous thrombolysis and/or endovascular treatment. Before treatment, each patient received computed tomography (CT), CT angiography, and CT perfusion. We assessed pretreatment BBB leakage within the ischemic area using the volume transfer constant (Ktrans ) value. Our primary outcome was relevant HT, defined as hemorrhagic infarction type 2 or parenchymal hemorrhage type 1 or 2. We evaluated independent associations between BBB leakage and HT using logistic regression, adjusting for age, sex, baseline stroke severity, Alberta Stroke Program Early CT Score (ASPECTS) ≥ 6, treatment type, and onset-to-treatment time. RESULTS: We enrolled 171 patients with available assessment of BBB leakage. The patients' mean (±SD) age was 75.5 (±11.8) years, 86 (50%) were men, and the median (interquartile range) National Institutes of Health Stroke Scale score was 18 (12-23). A total of 32 patients (18%) received intravenous thrombolysis, 102 (60%) underwent direct endovascular treatment, and 37 (22%) underwent both. Patients with relevant HT (N = 31;18%) had greater mean BBB leakage (Ktrans 0.77 vs. 0.60; p = 0.027). After adjustment in the logistic regression model, we found that BBB leakage was associated both with a more than twofold risk of relevant HT (odds ratio [OR] 2.50; 95% confidence interval [CI] 1.03-6.03 per Ktrans point increase; OR 2.34; 95% CI 1.06-5.17 for Ktrans values > 0.63 [mean BBB leakage value]) and with symptomatic intracerebral hemorrhage (OR 4.30; 95% CI 1.13-13.77 per Ktrans point increase). CONCLUSION: Pretreatment BBB leakage before reperfusion therapy was associated with HT, and may help to identify patients at risk of HT.

Occult radiological sacroiliac abnormalities in patients with inflammatory bowel disease who do not present signs or symptoms of axial spondylitis.

OBJECTIVES: To investigate radiological sacroiliac abnormalities in IBD patients without musculoskeletal symptoms and to determine the clinical and familiar differences between IBD patients with and without radiologic sacroiliac joint (SIJ) abnormalities. Subsequently, the patients with x-ray alterations were followed for 3 years in order to assess the onset of chronic inflammatory back pain (IBP). METHODS: 81 patients (55 Crohn-CD- and 26 ulcerative rettocolitis-UC) with remittent and low active IBD, from a tertiary referral centre of Gastroenterology Unit, were studied using SIJ x-rays. Differences in IBD clinical variables (activity and duration of CD and UC, extra-intestinal involvement, treatment with surgery and not, ESR and CRP levels), familiarity (for psoriasis, IBD, spondyloarthritis, coeliac syndrome), between patients with SIJ x-ray findings and without were investigated. Patients with radiological sacroiliac joint abnormalities were followed up clinically for 3 years and the onset of symptoms of chronic (higher than 3 consecutive months) IBP was investigated. RESULTS: 22/81 patients (27.1%) showed radiological SIJ abnormalities at baseline: isolated sclerosis in 17/22 (77.3%) and localised erosions in 12/22 (54.5%). Radiological SIJ involvement did not correlate with IBD clinical and familial variables. All patients were HLA B27 negative. At 3 years, 4/22 patients (18.1%) presented chronic IBP symptoms with bone oedema at MRI. CONCLUSIONS: In IBD, occult radiological SIJ alterations might precede the onset of axial symptoms but, in the absence of clinical signs, it is not possible to identify some IBD features or familiar predisposition that might be more frequent when SIJ abnormalities are involved. Clinical follow-up might be useful in these patients for a diagnosis of axial spondyloarthritis onset.

Ultrasound discloses entheseal involvement in inactive and low active inflammatory bowel disease without clinical signs and symptoms of spondyloarthropathy.

OBJECTIVE: To investigate the presence of lower limb entheseal abnormalities in IBD patients without clinical signs and symptoms of SpA and their correlation with IBD clinical variables. METHODS: A total of 81 IBD patients [55 Crohn's disease (CD) and 26 ulcerative colitis (UC), 43 females and 38 males, mean age 41.3 (12.4) years, BMI 24 (2)] with low active (12) and inactive (67) disease were consecutively studied with US (LOGIQ5 General Electric 10-MHz linear array transducer) of lower limb entheses and compared with 40 healthy controls matched for sex, age and BMI. Quadriceps, patellar, Achilleon and plantar fascia entheses were scored according to the 0-36 Glasgow Ultrasound Enthesitis Scoring System (GUESS) and power Doppler (PD). Correlations of GUESS and PD with IBD features [duration, type (CD/UC) and activity (disease activity index for CD/Truelove score for UC)] were investigated. The intra- and inter-reader agreements for US were estimated in all images detected in patients and controls. RESULTS: Of the 81 patients, 71 (92.6%) presented almost one tendon alteration with mean GUESS 5.1 (3.5): 81.5% thickness (higher than controls P < 0.05), 67.9% enthesophytosis, 27.1% bursitis and 16.1% erosions. PD was positive in 13/81 (16%) patients. In controls, US showed only enthesophytes (5%) and no PD. GUESS and PD were independent of duration, activity or type (CD/UC) of IBD. The intra- and inter-reader agreements were high (>0.9 intra-class correlation variability). CONCLUSIONS: US entheseal abnormalities are present in IBD patients without clinical signs and symptoms of SpA. US enthesopathy is independent of activity, duration and type of gut disease.

Atrial Fibrillation and Resistant Stroke: Does Left Atrial Appendage Morphology Matter? A Case Report.

Introduction: Patients with atrial fibrillation (AF) can experience ischemic stroke despite adequate anticoagulant therapy. The secondary prevention strategy of these so-called "resistant strokes" is empirical. Since about 90% of patients with ischemic stroke due to atrial fibrillation have thrombus in left atrial appendage (LAA) we sought to explore the possibility that resistant stroke could have a LAA morphology resistant to anticoagulants. Case Report: A 77 years old man affected by AF experienced two cardioembolic ischemic stroke while on anticoagulants. The study of LAA showed a windsock-like morphology in the proximal part while distally the LAA presented a cauliflower morphology with a large amount of pectinate muscles and blood stagnation. The precise characteristics of LAA were properly understood integrating images obtained by cardiac CT, transesophageal echocardiography, and selective angiography. A high risky LAA for thrombus formation was diagnosed and its occlusion (LAAO) as an add-on therapy to anticoagulants was proposed and performed. Six month follow-up was uneventfully. Conclusion: The systematic study of LAA in patients with resistant-stroke could help to identify LAA malignant morphology. The efficacy on stroke recurrence of the combined therapy (anticoagulants plus LAAO) is worthy to be tested in randomized trials.

Polyamine receptors containing dipyridine or phenanthroline units: clues for the design of fluorescent chemosensors for metal ions.

The synthesis of the macrocyclic receptor L1, which contains a tetraamine chain linking the 6,6'-positions of a 2,2'-dipyridine moiety, is reported. Its basicity properties and complexation features toward Cu(II), Zn(II), Cd(II) and Pb(II) have been studied in aqueous solutions by means of potentiometric, UV/Vis spectroscopy and fluorescence emission measurements and compared with those of ligand L2, in which a 1,10-phenanthroline moiety replaces the dipyridine unit of L1. In metal coordination, L1 shows a marked selectivity toward Cd(II) over Zn(II) and Pb(II). The crystal structures of its metal complexes shows that L1 possesses a preferential tetradentate binding site for metal cations, composed of the dipyridine unit and the two adjacent benzylic amine groups. This binding site has the proper dimension and conformation to selectively coordinate the Cd(II) ion, as confirmed by DFT calculations carried out on the complexes. This coordinative zone is lost in L2. The rigidity of phenanthroline does not allow the simultaneous binding of both the benzylic amine groups to Zn(II) and Cd(II) and, in fact, one benzylic amine is not coordinated to these metal cations. The fluorescence emission properties of the L1 and L2 complexes are strongly pH dependent. Only the Zn(II) and Cd(II) complexes with L1 display fluorescence emission at neutral pH. This feature is related to the formation in solution at pH 7 of emissive protonated complexes of the type [M(H(x)L)]((2+x)+) (x=1-3), in which all the nitrogen donors are involved in metal or proton binding. The emissive characteristics of these protonated complexes are confirmed by the fluorescence emission spectra collected on the [Zn(HL1)Br][ClO(4)](2) and [Cd(HL1)Br][ClO(4)](2) solid compounds dissolved in CH(3)CN. Conversely, the Zn(II) and Cd(II) complexes with L2 are not emissive; in fact, they contain a benzylic amine group not involved in metal or proton binding that can quench the fluorescence emission of the fluorophore, thanks to a photoinduced electron-transfer process.

Exploring the binding ability of phenanthroline-based polyammonium receptors for anions: hints for design of selective chemosensors for nucleotides.

The synthesis of receptor 2,6,10,14,18-pentaaza[20]-21,34-phenanthrolinophane (L1), containing a pentaamine chain linking the 2,9 positions of a phenanthroline unit, is reported. The protonation features of L1 and of receptor 2,6,10,14,18,22-hexaaza[23]-24,37-phenanthrolinophane (L2) have been studied by means of potentiometric, (1)H NMR, and spectrofluorimetric measurements; this study points out that the fluorescent emission of both receptors depends on the protonation state of the polyamine chain. In fact, the receptors are emissive only at neutral or acidic pH values, where all the aliphatic amine groups are protonated. Potentiometric titrations show that L2 is able to bind selectively ATP over TTP, CTP, and GTP. This selectivity is lost in the case of L1. (1)H and (31)P NMR measurements and molecular mechanics calculations show that the phosphate chains of nucleotides give strong electrostatic and hydrogen-bonding interactions with the ammonium groups of the protonated receptors, while the nucleobases interact either via pi-stacking with phenanthroline or via hydrogen bonding with the ammonium groups. Of note, MM calculations suggest that all nucleotides interact in an inclusive fashion. In fact, in all adducts the phosphate chain is enclosed within the receptor cavities. This structural feature is confirmed by the crystal structure of the [(H(6)L2)(2)(TTP)(2)(H(2)O)(2)](4+) adduct. Fluorescence emission measurements at different pH values show that L2 is also able to ratiometrically sense ATP in a narrow pH range, thanks to emission quenching due to a photoinduced electron transfer (PET) process from an amine group of the receptor to the excited phenanthroline.

Blood Biomarkers of Parenchymal Damage in Ischemic Stroke Patients Treated With Revascularization Therapies.

PURPOSE: Postischemic reperfusion injury may exacerbate cerebral damage and capillary dysfunction, leading to brain edema (BE), hemorrhagic transformation (HT), necrosis, and injury from free radicals with subsequent infarct growth (IG). Several plasmatic biomarkers involved in the ischemic cascade have been studied in relation to radiological and clinical outcomes of reperfusion injury in ischemic stroke with heterogeneous results. This article provides a brief overview of the contribution of circulating biomarkers to the pathophysiology of parenchymal damage in ischemic stroke patients treated with revascularization therapies. METHODS: We included full reports with measurements of plasma markers in patients with acute ischemic stroke treated with revascularization therapies. FINDINGS: Our research included a large number of observational studies investigating a possible role of circulating biomarkers in the development of parenchymal damage after acute stroke treatments. To make the results clearer, we divided the review in 4 sections, exploring the relation of different biomarkers with each of the indicators of parenchymal damage (HT, BE, IG, recanalization). DISCUSSION AND CONCLUSION: Definite conclusions are difficult to draw because of heterogeneity across studies. However, our review seems to confirm an association between some circulating biomarkers (particularly matrix metalloproteinase-9) and occurrence of parenchymal damage in ischemic stroke patients treated with revascularization therapies.

Small vessel disease and biomarkers of endothelial dysfunction after ischaemic stroke.

INTRODUCTION: Although pathogenesis of small vessel disease is poorly understood, increasing evidence suggests that endothelial dysfunction may have a relevant role in development and progression of small vessel disease. In this cross-sectional study, we investigated the associations between imaging signs of small vessel disease and blood biomarkers of endothelial dysfunction at two different time points in a population of ischaemic stroke patients. PATIENTS AND METHODS: In stroke patients treated with intravenous thrombolysis, we analysed blood levels of von Willebrand factor, intercellular adhesion molecule-1, vascular cell adhesion molecule-1 and vascular endothelial growth factor. Three reviewers independently assessed small vessel disease features using computed tomography. At baseline and 90 days after the index stroke, we tested the associations between single and combined small vessel disease features and levels of blood biomarkers using linear regression analysis adjusting for age, sex, hypertension, diabetes, smoke. RESULTS: A total of 263 patients were available for the analysis. Mean age (±SD) was 69 (±13) years, 154 (59%) patients were male. We did not find any relation between small vessel disease and endothelial dysfunction at baseline. At 90 days, leukoaraiosis was independently associated with intercellular adhesion molecule-1 (ß = 0.21; p = 0.016) and vascular cell adhesion molecule-1 (ß = 0.22; p = 0.009), and lacunes were associated with vascular endothelial growth factor levels (ß = 0.21; p = 0.009) whereas global small vessel disease burden was associated with vascular endothelial growth factor (ß = 0.26; p = 0.006). DISCUSSION: Leukoaraiosis and lacunes were associated with endothelial dysfunction, which could play a key role in pathogenesis of small vessel disease. CONCLUSIONS: Small vessel disease features and total burden were associated with endothelial dysfunction 90 days after the stroke, whereas there was no relation during the acute phase. Our results suggest that endothelial dysfunction, particularly vascular endothelial growth factor, is involved in pathological process of small vessel disease.

Interaction of mixed-donor macrocycles containing the 1,10-phenanthroline subunit with selected transition and post-transition metal ions: metal ion recognition in competitive liquid-liquid solvent extraction of Cu(II), Zn(II), Pb(II), Cd(II), Ag(I), and Hg(II).

Two new mixed aza-thia crowns 5-aza-2,8-dithia[9]-(2,9)-1,10-phenanthrolinophane (L(4)) and 2,8-diaza-5-thia[9]-(2,9)-1,10-phenanthrolinophane (L(7)) have been synthesized and characterized. The coordination behavior of L(4) and L(7) toward the metal ions Cu(II), Zn(II), Pb(II), Cd(II), Hg(II), and Ag(I) was studied in aqueous solution by potentiometric methods, in CD3CN/D2O 4:1 (v/v) by (1)H NMR titrations and in the solid state. The data obtained were compared with those available for the coordination behavior toward the same metal ions of structurally analogous mixed donor macrocyclic ligands L(1)-L(3), L(5), L(6): all these contain a phenanthroline subunit but have only S/O/N(aromatic) donor groups in the remaining portion of the ring and are, therefore, less water-soluble than L(4) and L(7). The complexes [Cd(NO3)2(L(5))], [Pb(L(7))](ClO4)2 x 1/2MeCN, [Pb(L(4))](ClO4)2 x MeCN, and [Cu(L(7))](ClO4)2 x 3/2MeNO2 were characterized by X-ray crystallography. The efficacy of L(1)-L(7) in competitive liquid-liquid metal ion extraction of Cu(II), Zn(II), Cd(II), Pb(II), Ag(I), and Hg(II) was assessed. In the absence of Hg(II), a clear extraction selectivity for Ag(I) was observed in all systems investigated.

A dizinc complex for selective fluorescence sensing of uridine and uridine-containing dinucleotides.

A dizinc complex with a polyamine macrocycle is able to selectively bind and sense uridine (U) as well as the uridine-containing ribodinucleotides U(3'-5')pU and U(3'-5')pA, thanks to an exciplex emission arising from a pi-stacked complex involving the dipyridine unit and Zn(II)-bound uridine moieties.

Satisfaction and expectations of patients with inflammatory bowel disease on biologic therapy: a multicenter study.

BACKGROUND: The satisfaction perceived by patients with chronic diseases affects clinical outcomes and healthcare costs. Some patients with inflammatory bowel disease (IBD) develop a more severe form requiring biologic therapy. We assessed the quality of care perceived by IBD patients in dedicated centers. METHODS: This prospective, cross-sectional, multicenter study enrolled consecutive IBD patients who underwent biologic therapy in the participating centers. The nurses directly involved in the management of these patients explained the rationale of the survey, provided a specific questionnaire (CACHE), and collected data. The CACHE included 31 items structured in 6 domains: staff care, clinician care, center facilities, patient information, accessibility, and patient support. Patients' satisfaction score for each domain ranged from 0 to 100%. RESULTS: Sixteen different Italian centers participated and a total of 450 patients were enrolled (283 with Crohn's disease and 167 with ulcerative colitis). The overall score was 82.2±19.6, satisfaction with the clinicians care scoring the highest (87.6±3.2) and the information provided to the patient scoring the lowest (70.7±7.9). More specifically, it emerged that 5.2-19.5% of patients were unsatisfied with: 1) the communication between the IBD medical team and primary care physicians; 2) information received about the disease or patients' associations; and 3) the accessibility of the center. CONCLUSION: Although our data revealed an acceptably high rate of global satisfaction among IBD patients receiving biologic therapy, more effort should be made to improve patient information and communication between IBD teams, other specialists and primary care physicians.

ATP recognition and sensing with a phenanthroline-containing polyammonium receptor.

A new polyammonium receptor is able to selectively recognise and sense ATP among triphosphate nucleotides, thanks to ATP-induced quantitative quenching of its fluorescence emission.

Orthodenticle is required for the development of olfactory projection neurons and local interneurons in Drosophila.

The accurate wiring of nervous systems involves precise control over cellular processes like cell division, cell fate specification, and targeting of neurons. The nervous system of Drosophila melanogaster is an excellent model to understand these processes. Drosophila neurons are generated by stem cell like precursors called neuroblasts that are formed and specified in a highly stereotypical manner along the neuroectoderm. This stereotypy has been attributed, in part, to the expression and function of transcription factors that act as intrinsic cell fate determinants in the neuroblasts and their progeny during embryogenesis. Here we focus on the lateral neuroblast lineage, ALl1, of the antennal lobe and show that the transcription factor-encoding cephalic gap gene orthodenticle is required in this lineage during postembryonic brain development. We use immunolabelling to demonstrate that Otd is expressed in the neuroblast of this lineage during postembryonic larval stages. Subsequently, we use MARCM clonal mutational methods to show that the majority of the postembryonic neuronal progeny in the ALl1 lineage undergoes apoptosis in the absence of orthodenticle. Moreover, we demonstrate that the neurons that survive in the orthodenticle loss-of-function condition display severe targeting defects in both the proximal (dendritic) and distal (axonal) neurites. These findings indicate that the cephalic gap gene orthodenticle acts as an important intrinsic determinant in the ALl1 neuroblast lineage and, hence, could be a member of a putative combinatorial code involved in specifying the fate and identity of cells in this lineage.

Genetic transformation of structural and functional circuitry rewires the Drosophila brain.

Acquisition of distinct neuronal identities during development is critical for the assembly of diverse functional neural circuits in the brain. In both vertebrates and invertebrates, intrinsic determinants are thought to act in neural progenitors to specify their identity and the identity of their neuronal progeny. However, the extent to which individual factors can contribute to this is poorly understood. We investigate the role of orthodenticle in the specification of an identified neuroblast (neuronal progenitor) lineage in the Drosophila brain. Loss of orthodenticle from this neuroblast affects molecular properties, neuroanatomical features, and functional inputs of progeny neurons, such that an entire central complex lineage transforms into a functional olfactory projection neuron lineage. This ability to change functional macrocircuitry of the brain through changes in gene expression in a single neuroblast reveals a surprising capacity for novel circuit formation in the brain and provides a paradigm for large-scale evolutionary modification of circuitry.

DNA binding of a proflavine derivative bearing a platinum hanging residue.

New platinum(II) complex of 3,6-diamine-9-[6,6-bis(2-aminohethyl)-1,6-diaminohexyl]acridine, AzaPt, has been synthesised and characterised. Behaviour of AzaPt in solution (protonation and possible self-aggregation phenomena) has been investigated by spectral methods (absorbance and fluorescence) at I=0.1M and 25°C, and the equilibrium parameters of binding to calf thymus DNA have been established. Two different modes of DNA binding by the complex were detected, which depend on the polymer to dye molar ratio (P/D). At relatively low P/D values the mode was interpreted as binding by the polyamine residue external to the base pairs, while at high P/D values the binding corresponds to intercalation of the proflavine residue. Such interpretation is supported by the observed salt effect on binding and the temperature variation of the binding constants, which allowed estimating the ΔH and ΔS values contributions. Spectrophotometric analysis of the long time range binding revealed that AzaPt is involved in a slow reaction, interpreted as an attack by the platinum ion on the nucleobases. The time constant for such interaction was calculated and found to be the same order of magnitude as for processes responsible for the action of anti-tumour drugs that do covalently bind to polynucleotides.

A highly pH-sensitive Zn(II) chemosensor.

Proton and Cu(II), Zn(II), Cd(II) and Pb(II) binding by ligand H(2)L, containing two bis(aminoethyl)amine (dien) units connected by a 2',7'-dichlorofluorescein (DCF) unit has been analyzed by means of potentiometric, UV-vis and fluorescence emission measurements. Considering proton binding, the ligand in its fully deprotonated form, L(2-), binds up to four acidic protons in the alkaline pH region. These protonation steps occur on the amine groups, whereas protonation of DCF takes place only below pH 4. In metal complexation, the ligand displays a marked selectivity for Zn(II) over Cd(II) and Pb(II), due to the better accommodation of the smaller and harder Zn(II) ion within the binding pocket generated by a dien unit and the adjacent deprotonated oxygen. The fluorescence emission study points out that Zn(II) binding is accompanied by a marked increase of the DCF emission from neutral to slightly alkaline pH values, where protonated forms of the complex are present in solution. The system is weakly emissive at slightly acidic pH values, where Zn(II) is essentially not bound to the receptor and above pH 9.5, probably due to the formation of the not protonated [ZnL] complex. Cd(II) binding gives rise to a much less intense increase of the emission only above pH 8.5, whereas Cu(II) and Pb(II) complexation leads to fluorescence quenching. Furthermore, the interaction of H(2)L with cells was investigated to explore its application as a new sensor for the evaluation of cellular Zn(II) content and distribution.

Binding of H+ and Zn(II) ions with a new fluorescent macrocyclic phenanthrolinophane.

The new macrocyclic ligand 1,9(4,7)-diphenanthroline-3,7,11,15-tetraazacyclohexadecaphane (L) was synthesized by a 2 : 2 reaction of 1,10-phenanthroline-4,7-dialdehyde with 1,3-diaminopropane, followed by reduction with NaBH(4). L contains two phenanthroline groups linked together by two 1,3-diaminopropane chains in such a way that the heteroaromatic nitrogen atoms point outside the ligand cavity. The ligand structure defines two pairs of identical compartments displaying a specific ability in the binding of protons (1,3-diaminopropane) and metal ions (phenanthroline). Protonation and Zn(II) coordination were studied by means of potentiometric and spectroscopic ((1)H NMR, UV-vis, fluorescence) techniques. Both protonation and Zn(II) coordination consistently affect the fluorescence emission properties of L, giving rise to enhancement or quenching of the emission, depending on the species involved. L becomes emissive upon protonation, but the formation of the highly protonated species, in particular the fully protonated [H(6)L](6+), quenches the emission. The mono- and dinuclear Zn(II) complexes of the unprotonated ligand are non-emissive, like free L, while Zn(II) binding to [HL](+) activates the emission. The most interesting aspect, however, is the chelation enhancement of quenching (CHEQ) observed upon Zn(II) binding to [H(2)L](2+) and [H(4)L](4+), being among the few examples of CHEQ effect observed for Zn(II) complexes. Hydrogen bonding between a metal coordinated water molecule and a phenanthroline group seems to be responsible for the CHEQ observed for [ZnH(2)L](4+).

DNA interaction with Ru(II) and Ru(II)/Cu(II) complexes containing azamacrocycle and dppz residues. A thermodynamic, kinetic and theoretical study.

Ru(ii) complexes that bring together the properties of the dppz (dipyrido[3,2-a:2',3'-c]phenazine) intercalating residue and the properties of metal-coordinating macrocycles (L = 4,4'-(2,5,8,11,14-pentaaza[15])-2,2'-bipyridilophane) have been synthesised and their protonation and affinity for copper(ii) was analysed. Ru(bpy)(dppz)L(2+) (D2(2+)) and Ru(dppz)(2)L(2+) (D3(2+)) were found to interact with DNA but the binding mode is not simple and its features strongly depend both on the ligand structure and on the [DNA]/[complex] ratio. Equilibrium measurements (spectrophotometric and spectrofluorometric titrations), kinetics (stopped-flow technique) and theoretical calculations all concur in suggesting that for the less hindered D2(2+) an important contribution of external binding, driven by dye-dye interactions, is operative, as revealed by the onset of positive cooperativity. On the contrary, for the bulkier D3(2+) complex dye-dye interactions are less effective, resulting in an intercalation process with lower dppz penetration within DNA slots. The Ru(bipy)(2)L(2+)(D1(2+))/DNA system was also analysed for comparison and helped in showing the non negligible contribution of the macrocycle to the binding process. The binding affinities of the macrocycle copper complexes for DNA are lower than those of their copper-free analogues only in the case of D1(2+), whereas an affinity enhancement in agreement with the charge increase upon copper coordination is observed for D2(2+) and D3(2+). Copper coordination produces complete loss of the cooperative behaviour in the case of D2(2+). Further mechanistic details are discussed.

Cu(ii) complexation with an acridine-containing macrocycle. Assembly of water cluster chains within the cavity of tetranuclear metallomacrocycles.

The synthesis and characterisation of a new macrocyclic compound (L), composed of a pentamine chain linking the 2,7 positions of an acridine moiety, is reported. Cu(ii) complexation was studied by means of potentiometric, UV-vis and EPR measurements in aqueous solutions. This study reveals that the ligand forms a stable tetranuclear complex with an overall [Cu(4)L(2)(OH)(4)](4+) stoichiometry in aqueous solution. The crystal structure of the [Cu(8)L(4)(micro-OH)(8)(micro-NO(3))(3)](NO(3))(5).32H(2)O complex, isolated from neutral aqueous solution, shows that it is formed by tetranuclear clusters [Cu(4)L(2)(micro-OH)(4)(micro-NO(3))(x)]((4-x)+) (x= 1 or 2), composed of two [Cu(2)L](4+) macrocyclic units linked together by four bridging hydroxide and nitrate anions to give an overall metallomacrocyclic structure. Magnetic measurements shows that the hydroxide-bridged Cu(ii) ions are ferromagnatically coupled. Inspection of the crystal packing shows that couples of metallomacrocycles are paired by pi-stacking interactions between acridine moieties, giving rise to an internal hydrophilic cavity were hexameric or pentameric water clusters are enclosed. The coupled metallomacrocycles assume a columnar disposition growing along the a axis, giving rise to channels passing through the cavities of the metallomacrocycles; these channels are filled by chains of 5- or 6-membered water clusters linked together by [NO(3).H(2)O](2) units.