Iron chelation effects on lipid peroxidation, inflammation and ventricular performance in a rat model of isoproterenol induced acute myocardial stress.

Acute cardiac pathologies represent one of the leading causes of death, while iron metabolism is recognized to be implicated in reactive oxygen species production, lipid peroxidation, and inflammation. The aim of the present study was to assess iron chelation effects in isoproterenol (ISO) induced acute cardiac stress. We divided male Wistar rats into preventive and secondary treatment groups, with the active arm consisting in deferiprone (DFP), a lipid permeable chelator. Mortality of ISO was 10-18.18% in both preventive and secondary groups. We analyzed serum and myocardial tissue parameters of inflammation, iron dynamics, and lipid peroxidation, accompanied by ultramicroscopy, histological, and ultrasound-derived parameters of left ventricular function. Results reveal that ISO-mediated lipid peroxidation and inflammation are alleviated by administration of DFP, with negligible effect on systemic ferroregulation dynamics and global ventricular function (as assessed by ultrasound). DFP administration after cardiovascular stress is associated with a decrease in lipid peroxidation and inflammation, without an improvement in gross left ventricular parameters.

A glycoporphyrin story: from chemistry to PDT treatment of cancer mouse models.

Photodynamic therapy (PDT) represents a non-toxic and non-mutagenic antitumor therapy. The photosensitizer's (PS) chemo-physical properties are essential for the therapy, being responsible for the biological effects induced in the targeted tissues. In this study, we present the synthesis and development of some glycoconjugated porphyrins based on lectin-type receptor interaction. They were tested in vitro for finally choosing the most effective chemical structure for an optimum antitumor outcome. The most effective photosensitizer is substituted by three diethylene glycol α-d-mannosyl groups. In vivo studies allow firstly the determination of some characteristics of the biological processes triggered by the initial photochemical activation. Secondly, they make it possible to improve the therapeutic protocol in the function of the structural architecture of the targeted tumor tissue.

Psoriasis and Metabolic Syndrome--scientific evidence and therapeutic implications.

Psoriasis is a chronic inflammatory disease, predominantly affecting the skin, being included in the group of Immune Mediated Inflammatory Diseases. Growing evidence from the last 10 years suggests that several systemic conditions like metabolic syndrome, cardiovascular disease, diabetes, psychological disorders or inflammatory bowel disease are prevalent in psoriasis patients. The linker might be the chronic secretion of pro-inflammatory cytokines. In this current review, the scientific evidence that explains the relationship between psoriasis and the metabolic syndrome in particular will be addressed, as the metabolic syndrome comprises a group of risk factors for cardiovascular disease, thus offering an overall picture of the systemic involvement in psoriasis. An integrated approach, with an early detection and treatment of the components of the metabolic syndrome, are important steps in psoriasis management. Attention should be paid on influence of psoriasis treatment upon comorbidities and vice-versa.

Lactate MRSI and DCE MRI as surrogate markers of prostate tumor aggressiveness.

Longitudinal studies of lactate MRSI and dynamic contrast-enhanced MRI were performed at 4.7 T in two prostate tumor models grown in rats, Dunning R3327-AT (AT) and Dunning R3327-H (H), to determine the potential of lactate and the perfusion/permeability parameter Ak(ep) as markers of tumor aggressiveness. Subcutaneous AT (n = 12) and H (n = 6) tumors were studied at different volumes between 100 and 2900 mm(3) (Groups 1-5). Lactate concentration was determined using selective multiple quantum coherence MRSI with the phantom substitution method. Tumor enhancement after the administration of gadolinium diethylenetriaminepenta-acetic acid was analyzed using the Brix-Hoffmann model and the Ak(ep) parameter was used as a measure of tumor perfusion/permeability. Lactate was not detected in the smallest AT tumors (Group 1; 100-270 mm(3) ). In larger AT tumors, the lactate concentration increased from 2.8 ± 1.0 mm (Group 2; 290-700 mm(3)) to 8.4 ± 2.9 mm (Group 3; 1000-1340 mm(3)) and 8.2 ± 2.2 mm (Group 4; 1380-1750 mm(3) ), and then decreased to 5.0 ± 1.7 mm (Group 5; 1900-2500 mm(3)), and was consistently higher in the tumor core than in the rim. Lactate was not detected in any of the H tumors. The mean tumor Ak(ep) values decreased with increasing volume in both tumor types, but were significantly higher in H tumors. In AT tumors, the Ak(ep) values were significantly higher in the rim than in the core. Histological hypoxic and necrotic fractions in AT tumors increased with volume from 0% in Group 1 to about 20% and 30%, respectively, in Group 5. Minimal amounts of hypoxia and necrosis were found in H tumors of all sizes. Thus, the presence of lactate and heterogeneous perfusion/permeability are signatures of aggressive, metabolically deprived tumors.

Acute embolic events--myocardial infarction and stroke, in the presence of an interatrial septal aneurysm.

We will present the case of a 52 year old patient, admitted to our Department for exertional angina, with 2 recent acute events--inferior myocardial infarction and stroke. The coronary angiography revealed patent coronary arteries, without atherosclerotic lesions. The transthoracic echocardiography established the presence of an interatrial septal aneurysm with interatrial shunt. Under these circumstances, we have considered the presence of paradoxical embolism as a potential pathophysiological mechanism of the acute ischemic events. The percutaneous closure of the interatrial shunt to prevent the recurrence of embolic events will be discussed.

[Towards a new treatment of retinoblastoma?]. / Vers un nouveau traitement du rétinoblastome ?

Photodynamic therapy (PDT) is a recent approach for the treatment of small cancerous tumours, on-surface or accessible by endoscopy in which a dye (usually a tetrapyrrolic macrocycle) absorbs light and generates cytotoxic reactive oxygen species leading to cellular damage. Retinoblastoma (Rb) is a rare intraocular tumour of childhood. All the multifocal forms are hereditary and constitute a syndrome of genetic predisposition in the cancer. The current treatments with etoposide or carboplatine expose the patient to the late risk of second cancer. The use of PDT as cancer therapy is particularly attractive due to the use of few mutagenic and non-toxic photosensitizers (PS) prior light excitation and to the localized tumour illumination. The photoefficiency towards Rb of a glycoconjugated porphyrin is discussed and compared with the results obtained with a second-generation photosensitizer, the Foscan. Some in vivo results on an animal model of Rb are presented by a point of view of photoefficiency, biodistribution, pharmacokinetic and longitudinal follow-up of the PDT effect using a new non-invasive method of magnetic resonance imaging of real-time. Photodynamic treatments in association with non-invasive sodium imaging open ways for new treatment tailoring or treatment individualization of retinoblastoma in clinic.

Principles of peripheral blood mononuclear cell apheresis in a preclinical canine model of hematopoietic cell transplantation.

BACKGROUND: Preclinical studies of peripheral blood mononuclear cell (PBMC) transplantation conducted in a well-established canine hematopoietic cell transplantation (HCT) model have been successfully translated to human patients over the past 5 decades. OBJECTIVE: We retrospectively investigated the safety and feasibility of PBMC apheresis in the canine model of HCT by analyzing apheresis parameters, cell yields, and the impacts of donor-related and apheresis-related variables on collection yields and donor stability. ANIMALS: One hundred and twenty dogs that underwent PBMC aphereses were evaluated. METHODS: Aphereses were performed with a COBE Spectra blood separator and a central dual-lumen catheter, with or without recombinant canine granulocyte colony-stimulating factor (rcG-CSF) stem cell mobilization. RESULTS: Aphereses from dogs not given rcG-CSF yielded an average volume of 280 +/- 42 mL containing an average of 15,086 +/- 9,834 leukocytes/mL. Aphereses from dogs given rcG-CSF yielded an average volume of 261 +/- 55 mL containing an average of 39,711 +/- 24,488 leukocytes/mL. Higher pre-apheresis white blood cell (WBC) counts correlated with higher apheresis WBC yields (R=0.50, P<.0001). The correlations of collection time, inlet volume, and collection flow rate on WBC yields were statistically significant but only weak to moderate in magnitude (R=0.34, P=.0001; R=0.38, P=.0006; R=0.26, P=.002, respectively) as were the correlations of collection time and inlet volume on collection volumes (R=0.30, P=.002; R=0.42, P<.0001, respectively). All dogs recovered promptly after PBMC aphereses and catheter removal, without complications. CONCLUSIONS AND CLINICAL IMPORTANCE: These data may be useful for translating PBMC apheresis technology to the field of veterinary oncology for the treatment of dogs with hematologic malignancies.

Five decades of progress in haematopoietic cell transplantation based on the preclinical canine model.

The preclinical canine model has proved valuable for the development of principles and techniques of haematopoietic cell transplantation (HCT) applicable to human patients. Studies in random-bred dogs concerning the impact of histocompatibility barriers on engraftment and graft-versus-host disease, the kinetics of immunological reconstitution, the efficacy of various pretransplant conditioning regimens, post-transplantation immunosuppression protocols, treatment of malignant diseases, and graft-versus-tumour effects have advanced HCT from an investigational therapy with uncertain clinical benefit half a century ago to an important treatment choice for thousands of patients treated annually in transplantation centres worldwide. More recent preclinical canine studies have resulted in the clinical translation of non-myeloablative, minimally invasive transplantation protocols that have extended allogeneic HCT to include older human patients with malignant and non-malignant, acquired or inherited haematological disorders, and those with comorbid conditions. Here, we review the contributions of the canine model to modern HCT and describe the usefulness of HCT for the treatment of canine haematological disorders.

An efficient design for birdcage probes dedicated to small-animal imaging experiments.

We are presenting, in this paper, a simple, easily reproducible and easily tuneable design for home-built birdcage probes inducing a linearly polarised B1 field. A simple tuning method is proposed which preserves the induced field homogeneity that characterises in general the birdcage design. This is achieved by adding two extra rings (link rings) that allow one to connect two opposed points on the birdcage end rings via tuning capacitors. All the development stages, from design to practical realisation, are presented, step by step, in order to facilitate experimentalist work. Some images obtained with the birdcage probe are presented, accompanied by the B1 maps in transverse as well as longitudinal planes. Finally, a few suggestions are made for obtaining a circularly polarised magnetic field configuration.

Evidences on sodium ions compartmentalization in biological systems due to pathological states. A noninvasive NMR study.

Noninvasive nuclear magnetic resonance was used to measure the relaxation decay curves of naturally occurring 23Na ions in several biological systems. Experimental results showed an increase of membrane bound population for pathologic samples as compared with control. The bound sodium population was put in evidence using singular value decomposition method. Thus, the singular values that are obtained without any a priori from the fitting the relaxation decay curves are a new parameter in characterizing the cellular state. In the presence of artificial biological membranes, 23Na bound strongly to membranes containing phosphatidylcholine (PC) and phosphatidylserine (PS), but not to membranes consisting of only PC. A large bound population also appeared in the presence of apoptotic epithelial cells, which are known to translocate PS to the cell surface. A role for PS was confirmed by showing that sodium binds to the surface of epithelial cells infected with Chlamydia psittaci, and the amplitude of the bound population increases with a time-course similar to the appearance of PS on the surface of dying cells. Finally, this approach could distinguish between normal perfused liver and liver undergoing ischemia, due most likely to the exposure of surface PS on apoptotic and necrotic cells in the damaged tissue. Taken together, these studies demonstrate that the analysis of 23Na relaxation decay curves could reveal the presence of cells undergoing apoptosis and/or necrosis in living tissues. Noninvasive 23Na NMR measurements could thus be envisioned for controlling the quality of organs before transplantation, for the detection of asymptomatic infections that result in death of the host cell or inflammation of the tissue, and for characterizing the efficiency of novel apoptosis-inducing drugs to treat cancer.

NMR study of the selective inhibition of water permeability of rat erythrocyte membrane.

The inhibition of water diffusion across the rat erythrocyte membrane was studied by NMR using two basically different types of inhibitory agents: PCMB and in vivo irradiation. The contribution of lipid and protein to water permeability revealed the inhibitory effect of each pathway. Internal contamination with tritium (25-115 mGy) reduces water permeability due to protein modifications; for doses higher than 100 mGy the lipid mediated mechanism seems also to be impaired. The same procedure enables one to assess the extent to which the higher water permeability of rat, compared to human, erythrocyte is due to one of the two pathways.

In vivo tritium contamination effects on water exchange across the erythrocyte membranes: a nuclear magnetic resonance study.

The effects produced by chronic in vivo tritium contamination on the process of water diffusion across the rat erythrocyte membranes were investigated using an NMR relaxation method. As the level of tritium intake increased, an inhibition of the water permeability was observed, reaching values of 40% for corresponding absorbed doses of about 100 mGy. The activation energy of the transport process was also significantly increased, suggesting that the mechanism of the water diffusion across the membrane had changed.

NMR investigation of the influence of procaine and its metabolites on the water exchange through human erythrocyte membranes.

The effect of procaine hydrochloride and its metabolites on the diffusional water exchange through erythrocyte membranes was investigated at 37 degrees C and at concentrations ranging between 5 X 10(-5) M and 5 X 10(-1) M by using the NMR manganese doping method. Procaine hydrochloride and 2-diethylaminoethanol have a moderate stimulating effect on the water exchange, of up to 20% at concentrations ranging between 10(-3) and 10(-2) M, while an increasing inhibitory effect was found at higher concentrations. The p-aminobenzoic acid has no effect on the water exchange up to 10(-2) M and, at higher concentrations, and apparent decreasing inhibition was noticed which is thought to be an artefact due to the uptake of Mn2+ by the cells. The temperature dependence studies suggest that procaine HCl enhances the uptake of Mn2+ by the cells. An opposite effect was found for rigid erythrocytes. The p-aminobenzoic acid and 2-diethylaminoethanol appeared to be more effective than procaine hydrochloride in increasing the uptake of Mn2+.

The uptake of manganese ions and the apparent thermal transition of the erythrocyte membranes.

The nuclear magnetic resonance manganese doping technique is currently used for the determination of the water diffusional exchange time through human erythrocyte membranes. An apparent thermal transition at 26 degrees C was noticed at 18-30 mM manganese doping in the suspending solution. An analysis in terms of a two-phase nuclear spin exchanging system revealed that apparent thermal transitions are expected to occur in the upper and lower temperature regions. They represent a shift from intermediate exchange rates where water diffusion through the membrane is dominant to either fast or slow exchange rates where proton relaxation is the controlling process. The lower temperature apparent transition may be altered by the intracellular manganese concentration; the lower the Mn2+ concentration the lower the transition. Also according to this interpretation only a fraction of the erythrocytes are significantly permeated by Mn2+. The upper transition depends on the Mn2+ concentration in the extracellular volume; it decreases with decreasing Mn2+ concentration.

Nuclear magnetic resonance investigation of human erythrocytes in the presence of manganese ions. Evidence for a thermal transition.

Water proton transverse relaxation was investigated in whole blood and washed erythrocytes samples, respectively, at various temperatures and manganese concentrations. Water diffusional exchange controls proton relaxation in whole blood samples at higher Mn2+ concentrations (20-30 mM) or in washed erythrocyte samples at low Mn2+ content (1-5 mM). Mn2+ uptake is significant in washed normal erythrocyte samples when its concentration is about 18 mM or higher in the medium, at temperatures below about 26 degrees C. The thermal transition as revealed by the NMR doping method represents a switch from a water exchange process, mainly seen in the higher temperature range, to a paramagnetic ion controlled water proton relaxation in the lower temperature range.

Inositol 1,4,5-trisphosphate mimics muscarinic response in Xenopus oocytes.

The enhanced metabolism of phosphoinositides, which is associated with a wide variety of stimuli and physiological responses, has been studied intensively. Berridge and his collaborators demonstrated that the first measurable reaction following cell membrane receptor activation is a rapid hydrolysis of phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2), and that the product of this reaction, inositol 1,4,5-trisphosphate (Ins(1,4,5)P3), could cause a release of non-mitochondrial calcium. These findings have been verified in other systems. Although the relationship between the hydrolysis of PtdIns(4,5)P2 and the mobilization of intracellular calcium was clearly demonstrated, the direct link between Ins(1,4,5)P3 production and the physiological response was only implied. We have investigated the possibility that the intracellular release of Ins(1,4,5)P3 mediates the muscarinic-cholinergic response is Xenopus oocytes, and we show here that intracellularly injected Ins(1,4,5)P3 mimics the muscarinic depolarizing chloride current in Xenopus oocytes. This is the first demonstration of a direct link between phosphoinositides metabolism and a neuro-transmitter-induced physiological response.

Neurotransmitter-caused increase in [3H]inositol incorporation into phosphatidylinositol de novo synthesis vs exchange.

[3H]inositol and 32Pi were simultaneously incorporated into rat parotid phosphatidylinositol. The ratio of [3H]/32Pi incorporation dropped dramatically following stimulation with muscarinic or alpha-adrenergic agonists and returned to control values following the addition of appropriate antagonists. The drop in [3H]/32Pi ratio can be explained by a rapid increase in de- novo synthesis of phosphatidylinositol following its receptor-mediated breakdown. The change in this ratio also provided evidence for the existence of CDP-DG + inositol in equilibrium phosphatidylinositol exchange reaction in the intact tissue.