Transport Properties in Multicomponent Systems Containing Cyclodextrins and Nickel Ions.

In this work, we propose a comprehensive experimental study of the diffusion of nickel ions in combination with different cyclodextrins as carrier molecules for enhanced solubility and facilitated transport. For this, ternary mutual diffusion coefficients measured by Taylor dispersion method are reported for aqueous solutions containing nickel salts and different cyclodextrins (that is, α-CD, ß-CD, and γ-CD) at 298.15 K. A combination of Taylor dispersion and other methods, such as UV-vis spectroscopy, will be used to obtain complementary information on these systems. The determination of the physicochemical properties of these salts with CDs in aqueous solution provides information that allows us to understand solute-solvent interactions, and gives a significant contribution to understanding the mechanisms underlying diffusional transport in aqueous solutions, and, consequently, to mitigating the potential toxicity associated with these metal ions. For example, using mutual diffusion data, it is possible to estimate the number of moles of each ion transported per mole of the cyclodextrin driven by its own concentration gradient.

Intracellular trafficking of AIP56, an NF-κB-cleaving toxin from Photobacterium damselae subsp. piscicida.

AIP56 (apoptosis-inducing protein of 56 kDa) is a metalloprotease AB toxin secreted by Photobacterium damselae subsp. piscicida that acts by cleaving NF-κB. During infection, AIP56 spreads systemically and depletes phagocytes by postapoptotic secondary necrosis, impairing the host phagocytic defense and contributing to the genesis of infection-associated necrotic lesions. Here we show that mouse bone marrow-derived macrophages (mBMDM) intoxicated by AIP56 undergo NF-κB p65 depletion and apoptosis. Similarly to what was reported for sea bass phagocytes, intoxication of mBMDM involves interaction of AIP56 C-terminal region with cell surface components, suggesting the existence of a conserved receptor. Biochemical approaches and confocal microscopy revealed that AIP56 undergoes clathrin-dependent endocytosis, reaches early endosomes, and follows the recycling pathway. Translocation of AIP56 into the cytosol requires endosome acidification, and an acidic pulse triggers translocation of cell surface-bound AIP56 into the cytosol. Accordingly, at acidic pH, AIP56 becomes more hydrophobic, interacting with artificial lipid bilayer membranes. Altogether, these data indicate that AIP56 is a short-trip toxin that reaches the cytosol using an acidic-pH-dependent mechanism, probably from early endosomes. Usually, for short-trip AB toxins, a minor pool reaches the cytosol by translocating from endosomes, whereas the rest is routed to lysosomes for degradation. Here we demonstrate that part of endocytosed AIP56 is recycled back and released extracellularly through a mechanism requiring phosphoinositide 3-kinase (PI3K) activity but independent of endosome acidification. So far, we have been unable to detect biological activity of recycled AIP56, thereby bringing into question its biological relevance as well as the importance of the recycling pathway.

The apoptogenic toxin AIP56 is a metalloprotease A-B toxin that cleaves NF-κb P65.

AIP56 (apoptosis-inducing protein of 56 kDa) is a major virulence factor of Photobacterium damselae piscicida (Phdp), a Gram-negative pathogen that causes septicemic infections, which are among the most threatening diseases in mariculture. The toxin triggers apoptosis of host macrophages and neutrophils through a process that, in vivo, culminates with secondary necrosis of the apoptotic cells contributing to the necrotic lesions observed in the diseased animals. Here, we show that AIP56 is a NF-κB p65-cleaving zinc-metalloprotease whose catalytic activity is required for the apoptogenic effect. Most of the bacterial effectors known to target NF-κB are type III secreted effectors. In contrast, we demonstrate that AIP56 is an A-B toxin capable of acting at distance, without requiring contact of the bacteria with the target cell. We also show that the N-terminal domain cleaves NF-κB at the Cys(39)-Glu(40) peptide bond and that the C-terminal domain is involved in binding and internalization into the cytosol.

Systemic macrophage and neutrophil destruction by secondary necrosis induced by a bacterial exotoxin in a Gram-negative septicaemia.

Bacterial modulation of phagocyte cell death is an emerging theme in pathogenesis. Here we describe the systemic destruction of macrophages and neutrophils by the Gram-negative Photobacterium damselae ssp. piscicida (Phdp) in fish pasteurellosis, a deadly systemic infection. Following experimental inoculation, Phdp spreads by bacteraemia and colonizes the organs, producing a septicaemic infection, and secretes the apoptogenic exotoxin AIP56 which is systemically disseminated. In experimental and natural pasteurellosis, destruction of macrophages and neutrophils by secondary necrosis following caspase-3-associated apoptosis was seen predominantly in the spleen, head kidney and gut lamina propria. Identical phagocyte destruction occurred after injection of rAIP56, but not of heat-inactivated rAIP56, or AIP56-negative Phdp strains, indicating that AIP56 is responsible for phagocyte destruction occurring in pasteurellosis. Active caspase-3 and active neutrophil elastase are present in the blood in advanced infection, indicating that phagocyte lysis by secondary necrosis is accompanied by release of tissue-damaging molecules. The AIP56-induced lysis of phagocytes represents a very efficient, self-amplifying etiopathogenic mechanism, because it results in two effects that operate in concert against the host, namely, evasion of the pathogen from a crucial defence mechanism through the destruction of both professional phagocytes, and release of tissue-damaging molecules. The induction by a bacterial exotoxin of in vivo systemic lysis of both professional phagocytes by secondary necrosis, now described for the first time, may represent an overlooked etiopathogenic mechanism operating in other infections of vertebrates.

Eficácia do propofol e da associaçäo de propofol e dexametasona no controle de náusea e vômito no pósðoperatório de laparoscopia ginecológica / Efficacy of propofol and propofol plus dexamethasone in controlling postoperative nausea and vomiting of gynecologic laparoscopy

Justificativa e objetivos - A laparoscopia ginecológica é procedimento que determina alta incidência de náusea e vômito no pósðoperatório. Este estudo teve por finalidade comparar a eficácia do propofol isoladamente ou em associaçäo com a dexametasona na prevençäo de náusea e vômito em pacientes submetidas à laparoscopia ginecológica. Método - Participaram do estudo 40 pacientes, estado físico ASA I e II com idades entre 18 e 46 anos, sem queixas gástricas prévias, submetidas à laparoscopia para diagnóstico ou cirurgia. As pacientes foram divididas em 2 grupos; o grupo 1 recebeu (soluçäo fisiológica 2 ml) e o grupo 2 dexametasona (8 mg), por via venosa antes da induçäo da anestesia. Todas as pacientes receberam midazolam (7,5 mg) por via oral como medicaçäo préðanestésica, sufentanil (0,5 µg.kgðû), propofol em infusäo contínua para induçäo e manutençäo da anestesia (BIS - 60) e N2O/O2 em fraçäo inspirada de O2 a 40 por cento e atracúrio (0,5 mg.kgðû) como bloqueador neuromuscular. A analgesia pós-operatória foi realizada com cetoprofeno (100 mg) e buscopam composto. As pacientes fora avaliadas na sala de recuperaçäo pós-anestésica (SRPA) e na enfermaria 1, 2, 3 e 12 horas após a alta da SRPA. Resultados - Ambos os grupos foram idênticos quanto aos dados antropométricos e à duraçäo da cirurgia e da anestesia. No grupo 1 (n = 20) uma paciente apresentou náusea na SRPA e na enfermaria e três pacientes vomitaram na enfermaria. No grupo 2 (n = 20) nenhuma paciente apresentou náusea ou vômito durante o período de observaçäo clínica, resultados estatisticamente näo significativos. Conclusões - O propofol isoladamente ou associado à dexametasona foi eficaz na prevençäo de náusea e vômito no pós-operatório de pacientes submetidas à laparoscopia ginecológica

[Efficacy of propofol and propofol plus dexamethasone in controlling postoperative nausea and vomiting of gynecologic laparoscopy.]. / Eficácia do propofol e da associação de propofol e dexametasona no controle de náusea e vômito no pós-operatório de laparoscopia ginecológica.

BACKGROUND AND OBJECTIVES: Gynecological laparoscopy is a procedure associated to a high incidence of postoperative nausea and vomiting (PONV). This study aimed at comparing the efficacy of propofol or propofol plus dexamethasone in preventing PONV in patients submitted to gynecological laparoscopy. METHODS: Forty female patients, physical status ASA I and II, aged 18 to 46 years, with no previous gastric complaint, undergoing diagnostic or surgical laparoscopy were randomly distri- buted in 2 groups: Group 1 - patients were given 2 ml IV saline solution, while Group 2 was given intravenous dexamethasone (8 mg), before anesthetic induction. All patients were premedicated with oral midazolam (7.5 mg) and induced with sufentanil (0.5 microg.kg-1) and propofol targed controlled infusion (BIS 60), with N2O/O2 (F I O2=0.4) for maintenance. Neuromuscular block was obtained with atracurium (0.5 mg.kg-1). Postoperative analgesia consisted of ketoprofen (100 mg) and butyl-eschopolamine plus dipirone. Patients were evaluated in the PACU and in the ward after 1, 2, 3 and 12 hours after PACU discharge. RESULTS: Both groups were identical regarding demographics data as well as surgery and anesthesia duration. One Group 1 patient referred nausea in postanesthetic care unit and in the ward, and 3 patients referred vomiting in the ward. In Group 2, no patient referred nausea and vomiting, but the difference was not statistically significant. CONCLUSIONS: Propofol or propofol plus dexamethasone were efficient in preventing PONV in patients submitted to gynecological laparoscopy.