Skin sensitization to fragrance hydroperoxides: interplay between dendritic cells, keratinocytes and free radicals.

BACKGROUND: Skin sensitization to hydroperoxides (R-OOHs) of the commonly used fragrance terpenes limonene, linalool and citronellol is frequently reported. R-OOHs are believed to initiate the process leading to sensitization and allergic contact dermatitis through mechanisms involving radical intermediates. Thus, radical intermediates, keratinocytes and dendritic cells (DCs) may act in concert to initiate the process. OBJECTIVES: To evaluate individual DC activation profiles by R-OOHs in the context of keratinocytes with regard to frequency, specificity and magnitude of upregulation. METHODS: We used 2D and 3D cocultures with keratinocytes/reconstructed human epidermis (RHE) and DCs to evaluate cell surface levels of the costimulatory molecules CD86, CD80 and the adhesion molecule CD54 on cocultured DCs. Analysis of radical formation from limonene hydroperoxides in RHE was performed using electron paramagnetic resonance combined with the spin trapping technique. RESULTS: R-OOHs induce donor-dependent DC activation. Major differences were found between the limonene-OOHs. Limonene-1-OOH was stronger with respect to both frequency and magnitude of response. Using a 3D coculture model, no DC activation was detected after topical application of 0·2% limonene-OOHs (20 µg cm-2 ), while 1·2% limonene-1-OOH or 2% limonene-2-OOH induced DC activation. Furthermore, we demonstrated differences in the carbon and oxygen radicals formed from the limonene-OOHs using RHE, mimicking what may happen in vivo. CONCLUSIONS: We report clear individual differences in DC maturation induced by the most important hydroperoxides. Response rates and magnitude of response both indicate that very small structural alterations in the hydroperoxides are translated into specific DC responses. In addition, we provide more insight into the amounts of hydroperoxides that can activate DCs and induce sensitization.

Characterization of NDM-1- and OXA-23-producing Acinetobacter baumannii isolates from inanimate surfaces in a hospital environment in Algeria.

BACKGROUND: Investigation of several outbreaks of multidrug-resistant Acinetobacter baumannii infection has demonstrated that contamination of the inanimate hospital environment could be implicated in the spread of these multidrug-resistant strains. AIM: To investigate the occurrence of carbapenem-resistant A. baumannii on inanimate surfaces and possible dissemination in the hospital environment in Algeria as a potential source of infection in humans. METHODS: A. baumannii strains were isolated from the hospital environment and identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Antimicrobial susceptibility was determined using disc diffusion and E-test methods. Carbapenemase activity was detected using microbiological tests, including modified Hodge test, modified Carba NP test, and EDTA test. Carbapenem resistance determinants were studied by polymerase chain reaction (PCR) and sequencing. Clonal relatedness was determined using multi-locus sequence typing (MLST). RESULTS: A total of 67 A. baumannii isolates were obtained from 868 environmental samples and identified by MALDI-TOF MS. Among them, 61 isolates were resistant to imipenem with minimum inhibitory concentration >32 µg/mL and positive by the modified Hodge test and modified Carba NP test. In addition, the activity of carbapenemase was inhibited by EDTA in 32 strains. PCR and sequencing showed the presence of blaOXA-23 gene in 29 strains, and the blaNDM-1 gene in 32 isolates. MLST demonstrated the presence of five types of ST (ST19, ST2, ST85, ST98, and ST115). CONCLUSION: Our study demonstrated the dissemination of carbapenemase-producing A. baumannii strains recovered from inanimate surfaces in a hospital environment, surrounding patients, healthcare workers and visitors, in Algeria as a potential source for nosocomial infection.

Emergence of KPC-producing Klebsiella pneumoniae ST512 isolated from cerebrospinal fluid of a child in Algeria.

We report class A carbapenemase (KPC)-3-producing Klebsiella pneumoniae meningitis in a 6-month-old child in Algeria. Multilocus sequence typing showed that the sequence type obtained corresponded to ST512, an allelic single-locus variant of the pandemic ST258 widely distributed in KPC producers from Europe. To our knowledge, this is the first report of KPC-3-producing K. pneumoniae ST512 in a North African country.

[Neurosecretory cells of the globuli I and the protocephalic neurosecretory pathway of the myriapods, diplodods. Preliminary observations on the Polydesmida, Platyrrhacidae, the Nematophora Lysiopetalidae, the Spirostreptida and the Spirobolida]. / Sur les cellules neurosécrétrices des globuli I et sur la voie neurosécrétrice protocéphalique des Myriapodes Diplopodes. Premiéres observations chez les polydesmida Platyrrhacidae, les nematophora Lysiopetalidae, les Spirostreptida et les Spirobolida

The Diplopods studied by the author and more particularly Platyrrhacidae, Lysiopetalidae, Spirostreptida and Spirobolida, show neurosecretory cells near the globuli I. The whole of his observations induces the author to admit a structural plan common to all the Diplopods: neurosecretory cells of globuli I--(NOG) nerve--neurohemal organ (Gabe's organ). Moreover he makes an attempt to compare his observations with those concerning another group of Myriapods: the Chilopods.

[The presence of para-esophageal bodies in Nematophora Lysiopetalidae (Myriapoda, Diplopoda)]. / Présence de corps para-oesophagiens chez les Nematophora Lysiopetalidae (Myriapoda, Diplopoda)

Demonstration of paraoesophageal bodies presence in the Millipede Nematophora Lysiopetalidae, Callipus foetidissimus (Savi, 1819). As in the Iulidae, Blaniulidae, Strongylosomidae and Glomeridia the paraoesophageal bodies are neurohemal organs having their own secretory cells. Different hypothesies on the origin of secretions in the paraoesophageal bodies of Lysiopetalidae are proposed.

Cytochemical and electron-microscopic study of the paraoesophageal bodies and related nerves in Schizophyllum sabulosum (L.), Diplopoda Julidae.

The ultrastructural study of the paraoesophageal bodies of Schizophyllum sabulosum reveals the occurrence of two axonal types (ax 1 and ax 2) near secretory cells. Two possibilities exist for the functional role of the nerves related to these paraoesophageal bodies. The results of treatment with proteases (pronase, pepsin, trypsin) and the identification of glycogen in both the paraoesophageal bodies and the nerves that link them to the brain and Gabe organs, suggest transport of at least part of the secretions from the paraoesophageal bodies to the Gabe organs.

[The paracommissural regions (brain neurohemal formations) of diplopods. Preliminary note]. / Les plages paracommissurales (formations neurohémales céphaliques) des Diplopodes. Note préliminaire

The paracommissural plates of Diplopods are neurohemal "organs" anatomically not individualized in bodies separate from the brain. They lie near the transverse commissure (tritocerebral commissure s.l.). They are composed of at least two distinct types of axon terminals, glial cells, tracheae and a neural lamella facing a blood sinus. The axons of paracommissural plates of originate in neurosecretory cells lying in the ganglions of the transverse commissure. The release of granules partly occurs by exocytosis.