Vogt-Koyanagi-Harada: treatment of recurrence after administration of 3 intravenous bolus of 1 g of corticosteroids and mycophenolate mofetil.

The case is presented on a young Honduran female with no medical history of note, who presented with multiple areas of exudative retinal detachment (RD), and a best-corrected visual acuity of 1.3 logMAR in both eyes. She was diagnosed with incomplete Vogt-Koyanagi-Harada syndrome, and treated early with a combination of intravenous therapy with 1 g of prednisolone per day for 3 days, as recommended by published evidence, as well as mycophenolate mofetil (2 g per day). During the corticosteroids tapering, there was a recurrence of exudative retinal detachments, and megadoses of 1 g of intravenous corticosteroids per day were reintroduced for 6 days until the complete resolution of the fluid of the exudative RD, and cyclosporine (100 mg per day), subtenon triamcinolone (40 mg/mL), and intravitreal ranibizumab once a month in the both eyes were added to the treatment, with a great control of choroidal inflammation that resulted in the remission of symptoms and signs.

Vogt-Koyanagi-Harada: tratamiento de la recurrencia tras la administración de 3 bolos intravenosos de 1g de corticoides y micofenolato de mofetilo / Vogt-Koyanagi-Harada: treatment of recurrence after administration of 3 intravenous bolus of 1g of corticosteroids and mycophenolate mofetil

Presentamos el caso de una mujer hondureña de 27 años sin antecedentes médicos de interés que presentó múltiples áreas de desprendimientos de retina (DR) exudativos y una mejor agudeza visual corregida de 1,3logMAR en ambos ojos. Fue diagnosticada de síndrome de Vogt-Koyanagi-Harada incompleto y tratada con prednisolona intravenosa (1g/24h) durante 3 días, tal y como recomienda la evidencia publicada, junto con micofenolato de mofetilo (2g/24h). Durante el descenso paulatino de corticoesteroides, los DR recidivaron, por lo que se reintrodujeron las megadosis de 1g/24h de corticoesteroides intravenosos durante 6 días hasta la resolución completa de los DR y se añadieron ciclosporina (100mg/24h), triamcinolona subtenoniana (40mg/mL) e inyecciones intravítreas mensuales de ranibizumab en ambos ojos, con un adecuado control de la inflamación coroidea que se tradujo en la remisión de los síntomas y signos (AU)

The case is presented on a young Honduran female with no medical history of note, who presented with multiple areas of exudative retinal detachment (RD), and a best-corrected visual acuity of 1.3logMAR in both eyes. She was diagnosed with incomplete Vogt-Koyanagi-Harada syndrome, and treated early with a combination of intravenous therapy with 1g of prednisolone per day for 3 days, as recommended by published evidence, as well as mycophenolate mofetil (2g per day). During the corticosteroids tapering, there was a recurrence of exudative retinal detachments, and megadoses of 1g of intravenous corticosteroids per day were reintroduced for 6 days until the complete resolution of the fluid of the exudative RD, and cyclosporine (100mg per day), subtenon triamcinolone (40mg/mL), and intravitreal ranibizumab once a month in the both eyes were added to the treatment, with a great control of choroidal inflammation that resulted in the remission of symptoms and signs (AU)

Vogt-Koyanagi-Harada: treatment of recurrence after administration of 3 intravenous bolus of 1g of corticosteroids and mycophenolate mofetil. / Vogt-Koyanagi-Harada: tratamiento de la recurrencia tras la administración de 3 bolos intravenosos de 1g de corticoides y micofenolato de mofetilo.

The case is presented on a young Honduran female with no medical history of note, who presented with multiple areas of exudative retinal detachment (RD), and a best-corrected visual acuity of 1.3logMAR in both eyes. She was diagnosed with incomplete Vogt-Koyanagi-Harada syndrome, and treated early with a combination of intravenous therapy with 1g of prednisolone per day for 3 days, as recommended by published evidence, as well as mycophenolate mofetil (2g per day). During the corticosteroids tapering, there was a recurrence of exudative retinal detachments, and megadoses of 1g of intravenous corticosteroids per day were reintroduced for 6 days until the complete resolution of the fluid of the exudative RD, and cyclosporine (100mg per day), subtenon triamcinolone (40mg/mL), and intravitreal ranibizumab once a month in the both eyes were added to the treatment, with a great control of choroidal inflammation that resulted in the remission of symptoms and signs.

Inactivation of Apaf1 reduces the formation of mutant huntingtin-dependent aggregates and cell death.

Polyglutamine expansions in some proteins associated with neurodegenerative diseases, such as Huntington's disease or several ataxias, lead to insoluble aggregates in the cell. These aggregates accumulate through a mechanism that is not yet fully understood, but it activates cell death pathways and contributes to kill the cell. Here, we show that apoptotic protease activating factor 1 (Apaf1) down-regulation, or treatment with pharmacological Apaf1 inhibitor SVT016426, decreases both polyglutamine-induced aggregation and polyglutamine-induced apoptotic cell death in different cellular models. We demonstrate that Apaf1 binds to both Htt and to heat shock protein chaperone Hsp70, and that this interaction is altered in the presence of the pharmacological inhibitor of Apaf1. Based on our findings, we hypothesize that Apaf1 enhances polyglutamine aggregation by reducing the cellular protein levels of available functional Hsp70.

Intrinsic caspase-8 activation mediates sensitization of erlotinib-resistant tumor cells to erlotinib/cell-cycle inhibitors combination treatment.

Inhibitors of the tyrosine kinase activity of epidermal growth factor receptor, as erlotinib, have an established role in treating several cancer types. However, resistance to erlotinib, particularly in breast cancer cell lines, and erlotinib treatment-associated disorders have also been described. Also, methods and combination therapies that could reverse resistance and ameliorate non-desirable effects represent a clinical challenge. Here, we show that the ATP non-competitive CDK2/cyclin A inhibitor NBI1 sensitizes erlotinib-resistant tumor cells to the combination treatment (co-treatment) for apoptosis-mediated cell death. Furthermore, in erlotinib-sensitive cells, the effective dose of erlotinib was lower in the presence of NBI1. The analysis in the breast cancer MDA-MB-468 erlotinib-resistant and in lung cancer A549 cell lines of the molecular mechanism underlying the apoptosis induced by co-treatment highlighted that the accumulation of DNA defects and depletion of cIAP and XIAP activates the ripoptosome that ultimately activates caspases-8 and -10 and apoptosis. This finding could have significant implications for future treatment strategies in clinical settings.

Modulation of cellular apoptosis with apoptotic protease-activating factor 1 (Apaf-1) inhibitors.

The programmed cell death or apoptosis plays both physiological and pathological roles in biology. Anomalous activation of apoptosis has been associated with malignancies. The intrinsic mitochondrial pathway of apoptosis activation occurs through a multiprotein complex named the apoptosome. We have discovered molecules that bind to a central protein component of the apoptosome, Apaf-1, and inhibits its activity. These new first-in-class apoptosome inhibitors have been further improved by modifications directed to enhance their cellular penetration to yield compounds that decrease cell death, both in cellular models of apoptosis and in neonatal rat cardiomyocytes under hypoxic conditions.

Small molecule inhibitors of Apaf-1-related caspase- 3/-9 activation that control mitochondrial-dependent apoptosis.

Apoptosis is a biological process relevant to human disease states that is strongly regulated through protein-protein complex formation. These complexes represent interesting points of chemical intervention for the development of molecules that could modulate cellular apoptosis. The apoptosome is a holoenzyme multiprotein complex formed by cytochrome c-activated Apaf-1 (apoptotic protease-activating factor), dATP and procaspase-9 that link mitochondria disfunction with activation of the effector caspases and in turn is of interest for the development of apoptotic modulators. In the present study we describe the identification of compounds that inhibit the apoptosome-mediated activation of procaspase-9 from the screening of a diversity-oriented chemical library. The active compounds rescued from the library were chemically optimised to obtain molecules that bind to both recombinant and human endogenous Apaf-1 in a cytochrome c-noncompetitive mechanism that inhibits the recruitment of procaspase-9 by the apoptosome. These newly identified Apaf-1 ligands decrease the apoptotic phenotype in mitochondrial-mediated models of cellular apoptosis.

Insights into the determinants of beta-sheet stability: 1H and 13C NMR conformational investigation of three-stranded antiparallel beta-sheet-forming peptides.

In a previous study we designed a 20-residue peptide able to adopt a significant population of a three-stranded antiparallel beta-sheet in aqueous solution (de Alba et al. [1999]Protein Sci.8, 854-865). In order to better understand the factors contributing to beta-sheet folding and stability we designed and prepared nine variants of the parent peptide by substituting residues at selected positions in its strands. The ability of these peptides to form the target motif was assessed on the basis of NMR parameters, in particular NOE data and 13Calpha conformational shifts. The populations of the target beta-sheet motif were lower in the variants than in the parent peptide. Comparative analysis of the conformational behavior of the peptides showed that, as expected, strand residues with low intrinsic beta-sheet propensities greatly disfavor beta-sheet folding and that, as already found in other beta-sheet models, specific cross-strand side chain-side chain interactions contribute to beta-sheet stability. More interestingly, the performed analysis indicated that the destabilization effect of the unfavorable strand residues depends on their location at inner or edge strands, being larger at the latter. Moreover, in all the cases examined, favorable cross-strand side chain-side chain interactions were not strong enough to counterbalance the disfavoring effect of a poor beta-sheet-forming residue, such as Gly.

Salmonid viral haemorrhagic septicaemia virus: fusion-related enhancement of virus infectivity by peptides derived from viral glycoprotein G or a combinatorial library.

To search for enhancers and/or inhibitors of viral haemorrhagic septicaemia virus (VHSV, a salmonid rhabdovirus) infectivity, a total of 51 peptides from a pepscan of viral envelope protein G, a recombinant peptide from protein G (frg11) and 80 peptide mixtures from an alpha-helix-favoured combinatorial library were screened. However, contrary to what occurs in many other enveloped viruses, only peptides enhancing rather than inhibiting VHSV infectivity were found. Because some of the enhancer pepscan G peptides and frg11 were derived from phospholipid-binding or fusion-related regions identified previously, it was suggested that enhancement of virus infectivity might be related to virus-cell fusion. Furthermore, enhancement was significant only when the viral peptides were pre-incubated with VHSV at the optimal low pH of fusion, before being adjusted to physiological pH and assayed for infectivity. Enhancement of VHSV infectivity caused by the pre-incubation of VHSV with peptide p5 (SAAEASAKATAEATAKG), one of the individual enhancer peptides defined from the screening of the combinatorial library, was independent of the pre-incubation pH. However, it was also related to fusion because the binding of p5 to protein G induced VHSV to bypass the endosome pathway of infection and reduced the low-pH threshold of fusion, thus suggesting an alternative virus entry pathway for p5-VHSV complexes. Further investigations into VHSV enhancer peptides might shed some light on the mechanisms of VHSV fusion.

Prospective evaluation of a model of prediction of invasive bacterial infection risk among children with cancer, fever, and neutropenia.

A risk prediction model for invasive bacterial infection (IBI) was prospectively evaluated among children presenting with cancer, fever, and neutropenia. The model incorporated assessment of 5 previously identified risk factors: serum level of C-reactive protein (CRP) >/=90 mg/L, hypotension, identification of relapse of leukemia as the cancer type, platelet count of

A synthetic hexapeptide (Argireline) with antiwrinkle activity.

Botulinum neurotoxins (BoNTs) represent a revolution in cosmetic science because of their remarkable and long-lasting antiwrinkle activity. However, their high neurotoxicity seriously limits their use. Thus, there is a need to design and validate non-toxic molecules that mimic the action of BoNTs. The hexapeptide Ac-EEMQRR-NH(2) (coined Argireline) was identified as a result of a rational design programme. Noteworthy, skin topography analysis of an oil/water (O/W) emulsion containing 10% of the hexapeptide on healthy women volunteers reduced wrinkle depth up to 30% upon 30 days treatment. Analysis of the mechanism of action showed that Argireline significantly inhibited neurotransmitter release with a potency similar to that of BoNT A, although as expected, it displayed much lower efficacy than the neurotoxin. Inhibition of neurotransmitter release was due to the interference of the hexapeptide with the formation and/or stability of the protein complex that is required to drive Ca(2+)-dependent exocytosis, namely the vesicular fusion (known as SNARE) complex. Notably, this peptide did not exhibit in vivo oral toxicity nor primary irritation at high doses. Taken together, these findings demonstrate that Argireline is a non-toxic, antiwrinkle peptide that emulates the action of currently used BoNTs. Therefore, this hexapetide represents a biosafe alternative to BoNTs in cosmetics.

Stabilization of an alpha-helical conformation in an isolated hexapeptide inhibitor of calmodulin.

The conformational properties of two hexapeptides, Ac-LWRILW-NH(2) and its D-amino acid counterpart Ac-lwrilw-NH(2), identified as calmodulin inhibitors using mixture-based synthetic combinatorial library approaches, have been characterised by NMR and CD spectroscopy. The peptides fold into an alpha-helical conformation in aqueous solution. The observed short- and medium-range nuclear Overhauser effects were consistent with the formation of an alpha-helical structure and a reasonably well-defined set of structures was obtained by using restraints from the NMR data in simulated annealing calculations. Analysis of glycine-substitution analogues demonstrated that all the amino acids that make up the peptide sequence are important for the stabilization of the alpha-helical conformation. The results suggest that a well-defined set of interactions is indispensable to allow alpha-helix formation in this short hexapeptide.

Prospective, multicenter evaluation of risk factors associated with invasive bacterial infection in children with cancer, neutropenia, and fever.

PURPOSE: To identify clinical and laboratory parameters present at the time of a first evaluation that could help predict which children with cancer, fever, and neutropenia were at high risk or low risk for an invasive bacterial infection. PATIENTS AND METHODS: Over a 17-month period, all children with cancer, fever, and neutropenia admitted to five hospitals in Santiago, Chile, were enrolled onto a prospective protocol. Associations between admission parameters and risk for invasive bacterial infection were assessed by univariate and logistic regression analyses. RESULTS: A total of 447 febrile neutropenic episodes occurred in 257 children. Five parameters were statistically independent risk factors for an invasive bacterial infection. Ranked by order of significance, they were as follows: C-reactive protein levels of 90 mg/L or higher (relative risk [RR], 4.2; 95% confidence interval [CI], 3.6 to 4.8); presence of hypotension (RR, 2.7; 95% CI, 2.3 to 3.2); relapse of leukemia as cancer type (RR, 1.8, 95% CI, 1.7 to 2.3); platelet count less than or equal to 50,000/mm(3) (RR, 1.7; 95% CI, 1.4 to 2.2); and recent (< or = 7 days) chemotherapy (RR, 1.3; 95% CI, 1.1 to 1.6). Other previously postulated risk factors (magnitude of fever, monocyte count) were not independent risk factors in this study population. CONCLUSION: In a large population of children, common clinical and laboratory admission parameters were identified that can help predict the risk for an invasive bacterial infection. These results encourage the possibility of a more selective management strategy for these children.

Functional and conformational properties of the exclusive C-domain from the Arabidopsis copper chaperone (CCH).

The Arabidopsis thaliana copper chaperone (CCH) is a small copper binding protein involved in copper trafficking. When compared to homologues from other eukaryotes, CCH has two different domains; the conserved N-domain and the plant-exclusive C-domain, a C-terminal extension with an unusual amino-acid composition. In order to characterize this extra C-domain, the CCH protein, the N-domain and the C-domain were all expressed separately in heterologous systems. While the N-domain retained the copper chaperone and antioxidant properties described for the yeast Atx1 and human HAH1 counterparts, the C-domain displayed particular structural properties that would be necessary to optimize copper homoeostasis in plant cells where it could be responsible for the metallochaperone plant-exclusive intercellular transport. The whole CCH protein and the C-domain, but not the N-domain, displayed altered SDS/PAGE mobilities. CD spectroscopy showed that the N-domain fold is representative of an alpha/beta protein, while the C-domain adopts an extended conformation.

Thermal stabilization of the catalytic domain of botulinum neurotoxin E by phosphorylation of a single tyrosine residue.

The catalytic domain of clostridial neurotoxins is a substrate of tyrosine-specific protein kinases. The functional role of tyrosine phosphorylation and also the number and location of its (their) phosphorylation site(s) are yet elusive. We have used the recombinant catalytic domain of botulinum neurotoxin E (BoNT E) to examine these issues. Bacterially expressed and purified BoNT E catalytic domain was fully active, and was phosphorylated in vitro by the tyrosine-specific kinase Src. Tyrosine phosphorylation of the catalytic domain increased the protein thermal stability without affecting its proteolytic activity. Covalent modification of the endopeptidase promoted a disorder-to-order transition, as evidenced by the 35% increment of the alpha-helical content, which resulted in a 4 degrees C increase of its denaturation temperature. Site-directed replacement of tyrosine at position 67 completely abolished phosphate incorporation by Src. Constitutively unphosphorylated endopeptidase mutants exhibited functional properties virtually identical to those displayed by the nonphosphorylated wild-type catalytic domain. These findings indicate the presence of a single phosphorylation site in the catalytic domain of clostridial neurotoxins, and that its covalent modification primarily modulates the protein thermostability.

Structural properties of carnation mottle virus p7 movement protein and its RNA-binding domain.

Plant viral movement proteins (MPs) participate actively in the intra- and intercellular movement of RNA plant viruses to such an extent that MP dysfunction impairs viral infection. However, the molecular mechanism(s) of their interaction with cognate nucleic acids are not well understood, partly due to the lack of structural information. In this work, a protein dissection approach was used to gain information on the structural and RNA-binding properties of this class of proteins, as exemplified by the 61-amino acid residue p7 MP from carnation mottle virus (CarMV). Circular dichroism spectroscopy showed that CarMV p7 is an alpha/beta RNA-binding soluble protein. Using synthetic peptides derived from the p7 sequence, we have identified three distinct putative domains within the protein. EMSA showed that the central region, from residue 17 to 35 (represented by peptide p7(17-35)), is responsible for the RNA binding properties of CarMV p7. This binding peptide populates a nascent alpha-helix in water solution that is further stabilized in the presence of either secondary structure inducers, such as trifluoroethanol and monomeric SDS, or RNA (which also changes its conformation upon binding to the peptide). Thus, the RNA recognition appears to occur via an "adaptive binding" mechanism. Interestingly, the amino acid sequence and structural properties of the RNA-binding domain of p7 seem to be conserved among carmoviruses and some other RNA-binding proteins and peptides. The low conserved N terminus of p7 (peptide p7(1-16)) is unstructured in solution. In contrast, the highly conserved C terminus motif (peptide p7(40-61)) adopts a beta-sheet conformation in aqueous solution. Alanine scanning mutagenesis of the RNA-binding motif showed how selected positive charged amino acids are more relevant than others in the RNA binding process and how hydrophobic amino acid side chains would participate in the stabilization of the protein-RNA complex.

[Causative agents of bloodstream infections in children with neoplasm, in 5 hospitals of Santiago (1994-1998)]. / Agentes causantes de infecciones del torrente circulatorio en niños con cáncer, en cinco hospitales de Santiago (1994-1998).

BACKGROUND: Pediatric patients in treatment for cancer can have fatal bacterial infections. Thus, in the presence of fever or other signs infection, antimicrobials have to be prescribed empirically. AIM: To know the causative agents of bacteremia in children with cancer, their changes with time and between different hospitals and their patterns of susceptibility. MATERIAL AND METHODS: We reviewed the blood cultores of children with cancer in five hospitals of Santiago, from 1994 at 1998. RESULTS: During the study period, 707 agents were isolated. The most frequently isolated species or genus were coagulase negative Staphylococcus (43%), Staphylococcus aureus (16%), Escherichia coli (9%), Klebsiella spp. (8%), Pseudomonas spp. (5%) and Candida spp. (4%). Coagulase negative Staphylococcus was 55% resistant to meticilin and S. aureus was 44% resistant. Enterobacteriaceae had 15% resistance to gentamicin and amikacin, 2% to imipenem, 26% to ceftriaxone, 21% to cefotaxime and 20% to ceftazidime. Among non fermenting agents resistance was 6% for imipenem, 9% for amikacin 10% for ciprofloxacin, 19% for ceftazidime and 22% for cefoperazone. The resistance of Streptococcus spp. (non pneumoniae) to penicillin reached 50% and that of Enterococcus spp. was of 33%. CONCLUSIONS: Treatment for pediatric patients with cancer must be modified and new guidelines including more active medications for patients at risk for bacteremia, should be devised.

Arginine-rich peptides are blockers of VR-1 channels with analgesic activity.

Vanilloid receptors (VRs) play a fundamental role in the transduction of peripheral tissue injury and/or inflammation responses. Molecules that antagonize VR channel activity may act as selective and potent analgesics. We report that synthetic arginine-rich hexapeptides block heterologously expressed VR-1 channels with submicromolar efficacy in a weak voltage-dependent manner, consistent with a binding site located near/at the entryway of the aqueous pore. Dynorphins, natural arginine-rich peptides, also blocked VR-1 activity with micromolar affinity. Notably, synthetic and natural arginine-rich peptides attenuated the ocular irritation produced by topical capsaicin application onto the eyes of experimental animals. Taken together, our results imply that arginine-rich peptides are VR-1 channel blockers with analgesic activity. These findings may expand the development of novel analgesics by targeting receptor sites distinct from the capsaicin binding site.

Influence of the hydrophilic face on the folding ability and stability of alpha-helix bundles: relevance to the peptide catalytic activity.

Although not the sole feature responsible, the packing of amino acid side chains in the interior of proteins is known to contribute to protein conformational specificity. While a number of amphipathic peptide sequences with optimized hydrophobic domains has been designed to fold into a desired aggregation state, the contribution of the amino acids located on the hydrophilic side of such peptides to the final packing has not been investigated thoroughly. A set of self-aggregating 18-mer peptides designed previously to adopt a high level of alpha-helical conformation in benign buffer is used here to evaluate the effect of the nature of the amino acids located on the hydrophilic face on the packing of a four alpha-helical bundle. These peptides differ from one another by only one to four amino acid mutations on the hydrophilic face of the helix and share the same hydrophobic core. The secondary and tertiary structures in the presence or absence of denaturants were determined by circular dichroism in the far- and near-UV regions, fluorescence and nuclear magnetic resonance spectroscopy. Significant differences in folding ability, as well as chemical and thermal stabilities, were found between the peptides studied. In particular, surface salt bridges may form which would increase both the stability and extent of the tertiary structure of the peptides. The structural behavior of the peptides may be related to their ability to catalyze the decarboxylation of oxaloacetate, with peptides that have a well-defined tertiary structure acting as true catalysts.