Kinetic effects of tartaric acid on the growth of chiral J-aggregates of tetrakis(4-sulfonatophenyl)porphyrin

The kinetics of growth for chiral J-aggregates of H(4)TPPS(4) porphyrin have been investigated under different experimental conditions in the presence of tartaric acid. The observed rate constants and the anisotropy factor g show a defined dependence on the enantiomer used as a chiral templating agent.

Design of photosensitizer/cyclodextrin nanoassemblies: spectroscopy, intracellular delivery and photodamage

The engineering of multifunctional nanoparticles carrying photosensitizer drugs (PS) and exposing binding groups for cellular receptors is of increasing interest in therapeutics and diagnostics applications. Natural and modified cyclodextrins (CDs) offer useful scaffolds to bind PS guests by supramolecular interactions. In particular, amphiphilic β-CDs, which form nanoaggregates of diverse shape and size according to the polarity of substituent groups on the rims, include in their different compartments as CD cavity, hydrophilic and hydrophobic portion, PS with different physicochemical properties. PS embedded in cationic amphiphilic CD nanoassemblies are effective in inducing photodynamic damage in cancer cells. For a carrier/PS system to be used in photodynamic therapy (PDT) or photodynamic diagnosis (PDD), the appropriate combination of the delivery characteristics with the preservation of the photodynamic activity of the PS is strictly required. Homogeneous multilayer films based on cationic amphiphilic β-CD entrapping anionic porphyrins can be constructed to exploit interfacial electrostatic interactions between the two components. The capability of CDs to generate restricted microenvironments for PS which can facilitate photoinduced energy transfer with suitable donor molecules was investigated for potential application in fluorescence diagnosis. Besides, recent findings suggest that PDT could represent a useful tool for properly addressing an alternative approach for killing pathogens and combating infections at a clinical level. Finally, modified CDs can bind gold nanoparticles, yielding hybrid organic/inorganic nanoparticles which were studied in water solution and after casting on solid substrates. These binary assemblies could further encapsulate PS or other conventional drugs, opening new intriguing routes on multimodal therapy.

Is childhood OCD a risk factor for eating disorders later in life? A longitudinal study

BACKGROUND

It has been suggested that childhood obsessive-compulsive disorder (OCD) may be a risk factor for the development of an eating disorder (ED) later in life, but prospective studies are lacking. We aimed to determine the prevalence of ED at follow-up and clinical predictors in a longitudinal clinical sample of adolescents/young adults diagnosed with OCD in childhood.

METHOD

All contactable (n=231) young people with OCD assessed over 9 years at a national and specialist paediatric OCD clinic were included in this study. At follow-up, 126 (57%) young people and parents completed the ED section of the Developmental and Well-being Assessment. Predictors for ED were investigated using logistic regression.

RESULTS

In total, 16 participants (12.7%) had a diagnosis of ED at follow-up. Having an ED was associated with female gender and persistent OCD at follow-up. There was a trend for family history of ED being predictive of ED diagnosis. Five (30%) of those who developed an ED at follow-up had ED symptoms or food-related obsessions/compulsions at baseline. A difference in predictors for an ED versus other anxiety disorders at follow-up was identified.

CONCLUSIONS

This study provides initial evidence that baseline clinical predictors such as female gender and family history of ED might be specific to the later development of ED in the context of childhood OCD. Clinicians should be alert to ED subthreshold symptoms in young girls presenting with OCD. Future longitudinal studies are needed to clarify the relationship between childhood OCD and later ED.

FC23-05 - Pregnancy and post-partum depression and anxiety in a longitudinal general population cohort: the effect of eating disorders and past depression

Aims

To investigate the effect of past depression, past and current eating disorders (ED) on perinatal anxiety and depression in a large general population cohort of pregnant women, the Avon Longitudinal Study of Parents And Children (ALSPAC).

Methods

Anxiety and depression were measured during and after pregnancy in 10,887 women, using the Crown-Crisp Experiential Inventory and Edinburgh Postnatal Depression Scale. Women were grouped according to depression and ED history: past ED with (n = 123) and without past depression (n = 50), pregnancy ED symptoms with (n = 77) and without past depression (n = 159), past depression only (n = 818) and controls (n = 9,660). We compared the course of depression and anxiety with linear mixed-effect regression models; and probable depressive and anxiety disorders using logistic regression.

Results

Women with both past depression and past/current ED had high anxiety and depression across time perinatally; this was most marked in the group with pregnancy ED symptoms and past depression (b coefficient:5.1 (95% CI 4.1-6.1), p < 0.0001), especially at 8 months post-partum. At 18 weeks in pregnancy all women (apart from those with past ED only) had a higher risk for a probable depressive and anxiety disorder compared to controls. At 8 months post-partum pregnancy ED symptoms and/or past depression conferred the highest risk for a probable depressive and anxiety disorder.

Conclusions

Pregnancy ED symptoms and past depression have an additive effect in increasing the risk for depression and anxiety perinatally. Screening at risk women for anxiety and depression in the perinatal period might be beneficial.

Sequence, stoichiometry, and dimensionality control in porphyrin/bis-calix[4]arene self-assemblies in aqueous solution

The use of a water-soluble octacationic bis-calix[4]arene with divergent cavities (BC(4)) as a templating agent for the assembly of a tetraanionic porphyrin (CuTPPS) has allowed the noncovalent synthesis of 2D or 3D multiporphyrin assemblies. Self-assembly of CuTPPS and BC(4) molecules proceeded under hierarchical control in a stepwise fashion to yield discrete and isolable supramolecular nanostructures containing up to 33 molecular elements (i.e., the CuTPPS/BC(4) 17:16 assembly, obtained in less than three hours). The formation of these species could be conveniently monitored by means of UV/Vis spectroscopy by following the absorbance of the Soret band at 412 nm. In particular, the attainment of the pivotal CuTPPS/BC(4) 5:4 species with a cruciform structure, as the key fork-point intermediate for the subsequent formation of the higher 2D and 3D assemblies, has been demonstrated by light-scattering studies and by an unequivocal synthesis of mixed-porphyrin/calixarene 5:4 species involving the use of two different types of metallated porphyrins, namely CuTPPS and MnTPPS. The remarkable stability of these assemblies permits a stepwise synthesis that makes it possible to choose the desired porphyrin sequence.

Spectroscopic investigation and molecular modeling on porphyrin/PAMAM supramolecular adduct

Noncovalent adducts (TPPC@PAMAM) between meso-tetrakis(4-carboxyphenyl)porphyrin (TPPC) and polyamidoamine PAMAM dendrimer (generation 2.0) have been obtained by simply mixing the two components at different stoichiometric amount. The resulting species are readily soluble and stable in aqueous solution up to millimolar concentration. Electrostatic interactions between the anionic carboxylate groups of TPPC and the protonated amino groups of the PAMAM dendrimer play an important role in the stabilization of these adducts. UV/Vis absorption, steady state and time-resolved fluorescence emission and anisotropy measurements suggest the presence of equilibria involving different species as function of the [PAMAM]/[TPPC] ratio. At low ratios the observed spectroscopic behavior evidence the presence of H-aggregates, while at higher ratios well-defined species containing monomeric TPPC strongly interacting with the charged dendrimer are formed. Docking of the binary supramolecular adduct further supports the experimental results showing a favorable interaction with the porphyrin being completely included in the dendrimer. The interaction of the binary TPPC@PAMAM adduct (1/1 ratio) with calf-thymus DNA has been investigated through spectroscopic and photophysical techniques. All the experimental results point to the formation of a ternary complex between the binary adduct and the DNA backbone.

Precision patterning with luminescent nanocrystal-functionalized beads

A reliable strategy is presented to combine the preparation of functional building blocks based on polymer beads decorated with luminescent nanocrystals (NCs) and their precise positioning onto suitable patterns by capillary assembly technique. In particular, a layer-by-layer (LbL) polyelectrolyte (PE) deposition procedure has been implemented to provide uniform NC coverage on PS beads, thus conveying the optical properties of luminescent nanocrystals to highly processable PS beads. The latter have then been integrated into patterned stamps by means of template-driven capillary assembly. Their selective positioning has been directed by means of pattern geometry. The use of luminescent (CdSe)ZnS NCs offers a direct optical probe to evaluate the efficiency of the positioning procedure on the substrate, enabling the extension of the method to a wide range of materials, i.e., NCs with different compositions and specific geometry-dependent properties. Moreover, the precise control over the pattern geometry and the micrometer accuracy in positioning achieved by capillary assembly make such functional patterned structures excellent candidates for integration into devices exploiting specific size-dependent NC properties.

Long-term outcomes of obsessive-compulsive disorder: follow-up of 142 children and adolescents

BACKGROUND

Obsessive-compulsive disorder (OCD) often starts in childhood and adolescence and can be a chronic disorder with high persistence rates. There are few prospective long-term follow-up studies.

AIMS

To follow up young people with OCD to clarify persistence rates and relevant predictors, presence of other psychiatric disorders, functional impairment, service utilisation and perceived treatment needs.

METHOD

All young people with OCD assessed over 9 years at the National and Specialist Paediatric OCD clinic, Maudsley Hospital, London, were included. Sixty-one per cent (142 of 222) of all contactable young people and parents completed computerised diagnostic interviews and questionnaires.

RESULTS

We found a persistence rate of OCD of 41%; 40% of participants had a psychiatric diagnosis other than OCD at follow-up. The main predictor for persistent OCD was duration of illness at assessment. High levels of baseline psychopathology predicted other psychiatric disorders at follow-up. Functional impairment and quality of life were mildly to moderately affected. Approximately 50% of participants were still receiving treatment and about 50% felt a need for further treatment.

CONCLUSIONS

This study confirms that paediatric OCD can be a chronic condition that persists into adulthood. Early recognition and treatment might prevent chronicity. Important challenges for services are ensuring adequate treatment and a smooth transition from child to adult services.

Aggregation properties of the peptide fragments derived from the 17-29 region of the human and rat IAPP: a comparative study with two PEG-conjugated variants of the human sequence

The amyloidogenic amino acid sequence Ac-VHSSNNFGAILSS-NH(2), corresponding to the 17-29 peptide region of human amylin (hIAPP17-29), was modified by grafting a hydrophilic PEG chain in order to obtain a novel class of peptides to be used as models to study the aggregation process of the full-length IAPP. The amphiphilic feature of the pegylated peptide fragment at the N-terminus (PEG-N-hIAPP17-29) drives the aggregation process toward stable micellar clusters without fibrillogenesis, despite the presence of beta-sheet interaction between peptides at pH values higher than 4.0. The hIAPP17-29-C-PEG, in which the PEG moiety is linked to the C-terminus, does not possess analogous amphiphilic character and the ability of PEG in forming H-bonds with the solvent overcomes that of the peptide chain, thereby causing peptide flocculation. The comparison with the unmodified hIAPP17-29 and the rat's peptide sequence Ac-VRSSNNLGPGLPP-NH(2)(rIAPP17-29) revealed the crucial role of hydrogen bonding between peptide and solvent in determining the aggregate structure and preventing fibril formation, as well as the non-negligible effect of a small amount of organic solvent in the aqueous solution which affects the aggregation process and rate.

Prep1 (pKnox1)-deficiency leads to spontaneous tumor development in mice and accelerates EmuMyc lymphomagenesis: a tumor suppressor role for Prep1

The Prep1 homeodomain transcription factor is essential for embryonic development. 25% of hypomorphic Prep1(i/i) embryos, expressing the gene at 2% of the normal levels, survive pregnancy and live a normal-length life. Later in life, however, these mice develop spontaneous pre-tumoral lesions or solid tumors (lymphomas and carcinomas). In addition, transplantation of E14.5 fetal liver (FL) Prep1(i/i) cells into lethally irradiated mice induces lymphomas. In agreement with the above data, haploinsufficiency of a different Prep1-deficient (null) allele accelerates EmuMyc lymphoma growth. Therefore Prep1 has a tumor suppressor function in mice. Immunohistochemistry on tissue micrroarrays (TMA) generated from three distinct human cohorts comprising a total of some 1000 human tumors revealed that 70% of the tumors express no or extremely low levels of Prep1, unlike normal tissues. Our data in mice are thus potentially relevant to human cancer.

Surfactant-like behavior of short-chain alcohols in porphyrin aggregation

UV/vis absorption and time-resolved fluorescence measurements on alcoholic solutions of meso-tetrakis(4-sulfonatophenyl)porphyrin (TPPS(4)) in neutral and acid form have been performed as a function of the alcohol polarity. These solutions show a peculiar behavior that mimics porphyrin in confined water solutions. In alcohols, TPPS(4) exhibits a metastable phase showing the formation of new species in analogy with the confined water environment of AOT microemulsions. Various species have been detected at different pH values and on aging the solutions. Under neutral pH conditions, the porphyrin is present as free base monomer (S415) with a small amount of H-dimeric species (S400). On aging, the S415 leads to the formation of a new species (S423), which has been assigned as a J-type dimer of the neutral porphyrin. The species S400 and S423 are not present in bulk water solution but are typical of TPPS(4) in confined water. On decreasing pH, the S415 almost immediately converts into the diacid form (S438), which evolves toward red-shifted J-aggregates (S490) and blue-shifted H-aggregates (S420). On decreasing alcohol polarity, the kinetic evolution from fresh to aged solution and from the monomeric diacid species to H- and J-aggregates speeds up. Exploiting the amphiphilic character of short chain alcohols and widely varying their polarity, we were able to enhance in bulk conditions the peculiar behavior observed in close proximity to the microemulsion wall.

Light Scattering as Spectroscopic Tool for the Study of Disperse Systems Useful in Pharmaceutical Sciences

The use of colloidal systems in pharmaceutical formulations, for addressing the issue of selective and controlled drug delivery or for improving drug availability, requires an accurate previous characterization of their chemical and physical properties. Light scattering is a useful and non-invasive method to study the structure and conformation of colloids in a wide space-scale, encompassing nanometric- to micrometric-sized particles, as well as their size distribution, surface electrostatic potential and aggregation phenomena occurring under proper conditions. In this review the physical bases of the light scattering approach are described and many examples are reported to discuss the examination of various multiphase systems useful in pharmaceutical fields.

Supramolecular porphyrin polymers in solution and at the solid-liquid interface

We have investigated in detail the self-assembly of a chiral porphyrin trimer in different solvents and correlated this behavior to the aggregation of the molecule at a solid-liquid interface. In n-hexane and cyclohexane, CD spectroscopy and dynamic and static light scattering studies showed that the porphyrin trimer self-assembles already at micromolar concentrations into long, chiral supramolecular polymers, which precipitate as fibers when the solution is drop-cast onto a mica surface. In contrast, in chloroform, the compound is molecularly dissolved up to concentrations of 0.2 mM and when micromolar solutions are drop-cast onto mica, no precipitation of large assemblies occurs. Instead, at the moment that the chloroform film becomes subject to spinodal dewetting and the porphyrin trimers within this film start to self-assemble, extended patterns of equidistant lines of single molecule thick columnar stacks are formed.

Childhood eating and weight in eating disorders: a multi-centre European study of affected women and their unaffected sisters

BACKGROUND

Previous studies have suggested that childhood eating and weight problems may be risk factors for eating disorders. Robust evidence is still lacking.

AIMS

To investigate whether childhood eating and weight problems increase the risk of eating disorders in affected women compared to their unaffected sisters.

METHODS

Women (150) with anorexia (AN) or bulimia nervosa (BN) recruited from clinical and community samples were compared to their unaffected sister closest in age on maternal reports of childhood eating and weight.

RESULTS

Women with BN were significantly more overweight at the ages of 5 and 10 (both OR = 2.8, p < 0.01), ate a lot (OR = 1.3, p < 0.01), were less picky (OR = 0.6, p < 0.05) and ate quickly (OR = 2.3, p < 0.05) between the ages of 6 and 10 compared to their healthy sisters. Significantly more women with AN were described as having a higher weight at 6 months (OR = 0.8, p < 0.01) and 1 year (OR = 0.6, p < 0.01) compared to their healthy sisters. Childhood eating was comparable in the women with AN and their unaffected sisters.

CONCLUSIONS

Traits of childhood overeating were more common in bulimic women compared to their unaffected siblings. Subjects with AN did not differ from their sisters on eating variables. The increased risk of BN due to childhood overweight suggests that prevention strategies for childhood obesity and overweight may therefore be applicable in BN.

From fractal to nanorod porphyrin J-aggregates. Concentration-induced tuning of the aggregate size

A structural change from fractal to nanorod J-aggregates of tetrakis(4-sulfonatophenyl)porphyrin has been obtained by acting on the intermolecular interaction potential. The size and shape of these self-assembled porphyrin clusters have been monitored under different experimental conditions, by means of polarized and depolarized dynamic light scattering and small and wide angle elastic light scattering. At sufficiently low porphyrin concentration and high ionic strength, the shielded repulsive potential seems to be responsible for the fractal structure of the aggregates. On the contrary, at low ionic strength (nonshielded potential) and high porphyrin concentration, these species self-assemble in a rodlike arrangement. The length of the so-formed rod-shaped aggregates decreases on increasing porphyrin concentration. Moreover, both fractals and rods display a structure-dependent optical activity induced by a chiral template.

Evidence of the early stage of porphyrin aggregation by enhanced Raman scattering and fluorescence spectroscopy

The early stage of fractal porphyrin diffusion-limited aggregation (DLA), induced by addition of a polyamine, is observed in aqueous solution by enhanced Raman scattering and fluorescence quenching. The enhancement of Raman scattering is due to nonlinear optical properties typical of fractal composites. Although this early stage (reaction-limited aggregation) has been theoretically predicted (by mean-field theory and molecular dynamics simulation), it is experimentally difficult to observe. During this initial stage, fluorescence quenching gives direct information on the decrease of the concentration of monomeric porphyrins, whereas Raman scattering (through characteristic vibrational modes of the aggregate) reports on the concentration of porphyrins in the aggregated form. These small clusters constitute the seeds for the DLA aggregation process leading to micrometric-sized fractals.