Keloid disease: Review with clinical atlas. Part I: Definitions, history, epidemiology, clinics and diagnosis.

Keloids are chronic progressive dermal pseudo-tumors that can grow considerably in volume and surface area but do not invade other tissues. They are usually triggered by dermal injury or inflammation, but they are not scars in the normal sense of the word, since they enlarge and progress over decades. The phenomenon usually referred to as "hypertrophic scars" represents a kind of keloidal process that does not extend beyond the initial site of injury and spontaneously regresses in 12-24 months. The multiplication of keloids and hypertrophic scars in a single patient is known as keloid disease. Keloid disease is due to a familial predisposition (autosomal dominant) that preferentially affects people of non-European ancestry, especially those of sub-Saharan African descent. Keloid disease has a deep impact on quality of life, not only because of disfiguring lesions, but also because of the frequency of associated intense neurogenic pruritus and pain, as well as recurrent bouts of suppuration. Diagnosis relies primarily on a good knowledge of the clinical characteristics of keloids, thus warranting the inclusion of a clinical atlas in the first part of the review. The second part will deal with the pathology, pathophysiology and treatment of keloid disease.

Antiglioma activity of GoPI-sugar, a novel gold(I)-phosphole inhibitor: chemical synthesis, mechanistic studies, and effectiveness in vivo.

Glioblastoma, an aggressive brain tumor, has a poor prognosis and a high risk of recurrence. An improved chemotherapeutic approach is required to complement radiation therapy. Gold(I) complexes bearing phosphole ligands are promising agents in the treatment of cancer and disturb the redox balance and proliferation of cancer cells by inhibiting disulfide reductases. Here, we report on the antitumor properties of the gold(I) complex 1-phenyl-bis(2-pyridyl)phosphole gold chloride thio-ß-d-glucose tetraacetate (GoPI-sugar), which exhibits antiproliferative effects on human (NCH82, NCH89) and rat (C6) glioma cell lines. Compared to carmustine (BCNU), an established nitrosourea compound for the treatment of glioblastomas that inhibits the proliferation of these glioma cell lines with an IC50 of 430µM, GoPI-sugar is more effective by two orders of magnitude. Moreover, GoPI-sugar inhibits malignant glioma growth in vivo in a C6 glioma rat model and significantly reduces tumor volume while being well tolerated. Both the gold(I) chloro- and thiosugar-substituted phospholes interact with DNA albeit more weakly for the latter. Furthermore, GoPI-sugar irreversibly and potently inhibits thioredoxin reductase (IC50 4.3nM) and human glutathione reductase (IC50 88.5nM). However, treatment with GoPI-sugar did not significantly alter redox parameters in the brain tissue of treated animals. This might be due to compensatory upregulation of redox-related enzymes but might also indicate that the antiproliferative effects of GoPI-sugar in vivo are rather based on DNA interaction and inhibition of topoisomerase I than on the disturbance of redox equilibrium. Since GoPI-sugar is highly effective against glioblastomas and well tolerated, it represents a most promising lead for drug development. This article is part of a Special Issue entitled: Thiol-Based Redox Processes.

Neutrophilic dermatoses.

Neutrophilic dermatoses (ND) are a group of inflammatory skin conditions characterized by a neutrophilic infiltrate on histopathology with no evidence of infection. ND are classified based upon the localization of neutrophils within the skin and clinical features. Recent findings suggest that ND are due to two main mechanisms: i) a polyclonal hereditary activation of the innate immune system (polygenic or monogenic); or ii) a clonal somatic activation of myeloid cells such as encountered in myelodysplastic syndrome or VEXAS syndrome. ND belong to internal medicine as a great number of patients with ND suffer from an underlying condition (such as hematological malignancy, inflammatory bowel disease, auto-immune and auto-inflammatory diseases). ND are diagnoses of exclusion and physicians should always consider differential diagnoses, particularly skin infections. Here, we review the pathophysiology and classification of the main ND (i.e., subcorneal pustular dermatosis (Sneddon-Wilkinson Disease) and Intercellular IgA dermatoses, aseptic pustulosis of the folds, Sweet syndrome, neutrophilic eccrine hidradenitis, pyoderma gangrenosum, erythema elevatum diutinum, neutrophilic urticarial dermatosis and neutrophilic panniculitis), their clinical and histopathological features, and we highlight the investigations that are useful to identify ND-associated diseases and to exclude the differential diagnoses.

[Video: An innovation for developmental care in the neonatal intensive care unit]. / La surveillance vidéo : une innovation au service des soins de développement en unité de soins intensifs de néonatologie.

INTRODUCTION: Our neonatal intensive care unit (NICU) was designed with a web-camera system in eight private rooms and four open wards. This equipment was installed to both guarantee children's safety in the NICU and promote the bond between the child and his/her family through a viewing service permitted by an Internet access. METHOD: We evaluated the web-camera system in its 5th year with two types of users. The nursing staff was asked about use of the video and its impact on their management of NICU patients. Questionnaires for parents sought to determine how they used the system and their feelings about it. RESULTS: Ninety-three percent of the nursing staff used the web-camera system to provide medical supervision or to comply with developmental care, mainly to respect the baby's natural rhythm by initiating care only when the baby showed signs of awakening. The web-camera system allowed them to observe the baby, verify his/her good body position, and spot discomfort situations. It helped provide a faster and personalized answer that was adjusted to the baby's needs. Sixty-one percent of the parents used the remote connection, half of them to present the child to the family. Only 17% of parents were embarrassed by the cameras; 88% of parents thought that the video was an additional safety device in NICU management. CONCLUSION: The web-camera system appeared to be an interesting technology in the NICU to support developmental care when children could be put in private rooms. It helped staff react faster to situations that created an inappropriate stimulation for the baby. It also allowed to them to respect the baby's natural rhythm. It reassured nursing staff and parents and it facilitated the baby's integration into the family.

Evidence for the co-existence of glutathione reductase and trypanothione reductase in the non-trypanosomatid Euglenozoa: Euglena gracilis Z.

Two NADPH-dependent disulfide reductases, glutathione reductase and trypanothione reductase, were shown to be present in Euglena gracilis, purified to homogeneity and characterized. The glutathione reductase (Mr 50 kDa) displays a high specificity towards glutathione disulfide with a KM of 54 microM. The amino acid sequences of two peptides derived from the trypanothione reductase (Mr 54 kDa) show a high level of identity (81% and 64%) with sequences of trypanothione reductases from trypanosomatids. The trypanothione reductase is able to efficiently reduce trypanothione disulfide (KM 30.5 microM) and glutathionylspermidine disulfide (KM 90.6 microM) but not glutathione disulfide, nor Escherichia coli thioredoxin disulfide, nor 5,5'-dithiobis(2-nitrobenzoate) (DTNB). These results demonstrate for the first time (i) the existence of trypanothione reductase in a non-trypanosomatid organism and (ii) the coexistence of trypanothione reductase and glutathione reductase in E. gracilis.

Antimalarial, antitrypanosomal, and antileishmanial activities and cytotoxicity of bis(9-amino-6-chloro-2-methoxyacridines): influence of the linker.

Forty bis(9-amino-6-chloro-2-methoxyacridines), in which acridine moieties are joined by alkanediamines, polyamines, or polyamines substituted by a side chain, were synthesized and tested for their in vitro activity upon the erythrocytic stage of Plasmodium falciparum, trypomastigote stage of Trypanosoma brucei, and amastigote stage of Trypanosoma cruzi and Leishmania infantum as well as for their cytotoxic effects upon MRC-5 cells. Results clearly showed the importance of the nature of the linker and of its side chain for antiparasitic activity, cytotoxicity, and cellular localization. Among several compounds devoid of cytotoxic effects at 25 microM upon MRC-5 cells, one displayed IC(50) values ranging from 8 to 18 nM against different P. falciparum strains while three others totally inhibited T. brucei at 1.56 microM.

A prodrug form of a Plasmodium falciparum glutathione reductase inhibitor conjugated with a 4-anilinoquinoline.

Glutathione (GSH), which is known to guard Plasmodium falciparum from oxidative damage, may have an additional protective role by promoting heme catabolism. An elevation of GSH content in parasites leads to increased resistance to chloroquine (CQ), while GSH depletion in resistant P. falciparum strains is expected to restore the sensitivity to CQ. High intracellular GSH levels depend inter alia on the efficient reduction of GSSG by glutathione reductase (GR). On the basis of this hypothesis, we have developed a new strategy for overcoming glutathione-dependent 4-aminoquinoline resistance. To direct both a 4-aminoquinoline and a GR inhibitor to the parasite, double-drugs were designed and synthesized. Quinoline-based alcohols (with known antimalarial activity) were combined with a GR inhibitor via a metabolically labile ester bond to give double-headed prodrugs. The biochemically most active double-drug 7 of this series was then evaluated as a growth inhibitor against six Plasmodium falciparum strains that differed in their degree of resistance to CQ; the ED(50) values for CQ ranged from 14 to 183 nM. While the inhibitory activity of the original 4-aminoquinoline-based alcohol followed that of CQ in these tests, the double-drug exhibited similar efficiency against all strains, the ED(50) being as low as 28 nM. For the ester 7, a dose-dependent decrease in glutathione content and GR activity and an increase in glutathione-S-transferase activity were determined in treated parasites. The drug was subsequently tested for its antimalarial action in vivo using murine malaria models infected with P. berghei. A 178% excess mean survival time was determined for the animals treated with 40 mg/kg 7 for 4 days. No cytotoxicity due to this compound was observed. Work is in progress to extend and validate the strategy outlined here.

Antiplasmodial activity and cytotoxicity of bis-, tris-, and tetraquinolines with linear or cyclic amino linkers.

Bisquinoline heteroalkanediamines were structurally modified in order to study the effects of enhanced bulkiness and rigidity on both their activity on strains of Plasmodium falciparum expressing different degrees of chloroquine (CQ) resistance and their cytotoxicity toward mammalian cells. While cyclization yielded molecules of greater rigidity that were not more active than their linear counterparts, they were characterized by an absence of cytotoxicity. Alternatively, dimerization of these compounds led to tetraquinolines that are very potent for CQ-resistant strains and noncytotoxic.

2- and 3-substituted 1,4-naphthoquinone derivatives as subversive substrates of trypanothione reductase and lipoamide dehydrogenase from Trypanosoma cruzi: synthesis and correlation between redox cycling activities and in vitro cytotoxicity.

Trypanothione reductase (TR) is both a valid and an attractive target for the design of new trypanocidal drugs. Starting from menadione, plumbagin, and juglone, three distinct series of 1,4-naphthoquinones (NQ) were synthesized as potential inhibitors of TR from Trypanosoma cruzi (TcTR). The three parent molecules were functionalized at carbons 2 and/or 3 by various polyamine chains. Optimization of TcTR inhibition and TcTR specificity versus human disulfide reductases was achieved with the 3,3'-[polyaminobis(carbonylalkyl)]bis(1,4-NQ) series 19-20, in which an optimum chain length was determined for inhibition of the trypanothione disulfide reduction. The most active derivatives against trypanosomes in cultures were also studied as subversive substrates of TcTR and lipoamide dehydrogenase (TcLipDH). The activities were measured by following NAD(P)H oxidation as well as coupling the reactions to the reduction of cytochrome c which permits the detection of one-electron transfer. For TcTR, 20(4-c) proved to be a potent subversive substrate and an effective uncompetitive inhibitor versus trypanothione disulfide and NADPH. Molecular modeling studies based on the known X-ray structures of TcTR and hGR were conducted in order to compare the structural features, dimensions, and accessibility of the cavity at the dimer interface of TcTR with that of hGR, as one of the putative NQ binding sites. TcLipDH reduced the plumbagin derivatives by an order of magnitude faster than the corresponding menadione derivatives. Such differences were not observed with the pig heart enzyme. The most efficient and specific subversive substrates of TcTR and TcLipDH exhibited potent antitrypanosomal activity in in vitro T. brucei and T. cruzi cultures. The results obtained here confirm that reduction of NQs by parasitic flavoenzymes is a promising strategy for the development of new trypanocidal drugs.

Specific inhibitors of Plasmodium falciparum thioredoxin reductase as potential antimalarial agents.

Plasmodium falciparum thioredoxin reductase (PfTrxR: NADPH+Trx(S)2+H+<-->NADP++Trx(SH)2) is a high Mr flavin-dependent TrxR that reduces thioredoxin (Trx) via a CysXXXXCys pair located penultimately to the C-terminal Gly. In this respect, PfTrxR differs significantly from its human counterpart which bears a Cys-Sec redox pair at the same position. PfTrxR is essentially involved in antioxidant defense and redox regulation of the parasite and has been previously validated by knock-out studies as a potential drug target for malaria chemotherapy. Moreover, human TrxR is present in most cancer cells at levels tenfold higher than in normal cells. Here we report the discovery of a series of potent inhibitors of PfTrxR. The three most promising inhibitors, 3(IC50(PfTrxR)=2 microM and IC50(hTrxR)=50 microM), 7(IC50(PfTrxR)=2 microM and IC50(hTrxR)=140 microM), and 11(IC50(PfTrxR)=0.5 microM and IC50(hTrxR)=4 microM) were selective for the parasite enzyme. Detailed mechanistic characterization of the effects of these compounds on the PfTrxR-catalyzed reaction showed clear uncompetitive inhibition with respect to both substrate and cofactor. For the most specific PfTrxR inhibitor 7, an alkylation mechanism study based on a thiol conjugation model was performed. Furthermore, all three compounds were active in the lower micromolar range on the chloroquine-resistant P. falciparum strain K1 in vitro.

The conserved redox-sensitive cysteine residue of the DNA-binding region in the c-Rel protein is involved in the regulation of the phosphorylation of the protein.

The DNA-binding activity of the transcription nuclear factor kappaB (NF-kappaB) is regulated by a redox-control mechanism involving the reduction of a disulphide bond from a specific cysteine residue conserved in all members of the NF-kappaB family. Thioredoxin is involved in this redox control. DNA binding and transactivating capacity of NF-kappaB are up-regulated by inducible phosphorylation. Here we demonstrate that the conserved redox cysteine in the c-Rel protein is involved in the phosphorylation regulation of the protein. When this cysteine residue is mutated to an aspartic acid residue, the mutant protein loses its capacity to be phosphorylated and its DNA-binding activity. In addition, our results suggest that, when the conserved redox cysteine is chemically modified by N-ethylmaleimide and 2-chloro-1,3-dinitrobenzene, the protein c-Rel cannot be phosphorylated. In contrast, the protein in which the cysteine residue was replaced by a serine residue, creating a potential phosphorylation site, is highly phosphorylated and binds kappaB sequences. The protein could loose the redox regulation of the phosphorylation when the residue replacing the cysteine can be itself phosphorylated. We also show that specific inhibitors of thioredoxin reductases impair the phosphorylation of the c-Rel protein, suggesting that the redox regulation of the protein controls its phosphorylation.

New spermine and spermidine derivatives as potent inhibitors of Trypanosoma cruzi trypanothione reductase.

Several spermine and spermidine derivatives containing 2-amino diphenylsulfide substituents were prepared and tested for their inhibiting effects on Trypanosoma cruzi trypanothione reductase. IC50 values were assessed between 0.3 and 3 microM. Compound 32 (Ki = 0.4 microM) is the most potent TR inhibitor described so far.

Glutathione-dependent activities of Trypanosoma cruzi p52 makes it a new member of the thiol:disulphide oxidoreductase family.

Trypanothione: glutathione disulphide thioltransferase of Try-panosoma cruzi (p52) is a key enzyme in the regulation of the intracellular thiol-disulphide redox balance by reducing glutathione disulphide. Here we show that p52, like other disulphide oxidoreductases possessing the CXXC active site motif, catalyses the reduction of low-molecular-mass disulphides (hydroxyethyl-disulphide) as well as protein disulphides (insulin). However, p52 seems to be a poor oxidase under physiological conditions as evidenced by its very low rate for oxidative renaturation of reduced ribonuclease A Like thioltransferase and protein disulphide isomerase, p52 was found to possess a glutathione-dependent dehydroascorbate reductase activity. The kinetic parameters were in the same range as those determined for mammalian dehydroascorbate reductases. A catalytic mechanism taking into account both trypanothione- and glutathione-dependent reduction reactions was proposed. This newly characterized enzyme is specific for the parasite and provides a new target for specific chemotherapy.

A general approach to the synthesis of polyamine linked-monoindolylmaleimides, a new series of trypanothione reductase inhibitors.

A simplified approach to the synthesis of 2-polyamine linked-monoindolylmaleimides has been achieved, leading to a new series of trypanothione reductase inhibitors. The conditions of access to N,2-bis(polyamine)-3-monoindolylmaleimides and N,N'-bis(monoindolylmaleimide) polyamines are described. Measured inhibitory activities towards trypanothione reductase from Tryanosoma cruzi show the importance of both aromatic moieties and polyamine chains for trypanothione reductase recognition.

Structure-activity relationships in 2-aminodiphenylsulfides against trypanothione reductase from Trypanosoma cruzi.

In order to establish structural elements responsible for inhibition of trypanothione reductase (TR) from Trypanosoma cruzi by 2-aminodiphenylsulfides, a series of dissymmetrical derivatives, corresponding to the replacement of one aromatic moiety by different amines, was synthesized. TR inhibition studies revealed the importance of the aromatic rings and of the amino groups in the side chains for potent inhibition. Quinonic moities were also introduced with the aim of acting as TR redox-cycling substrates.