A spatio-temporal model for spontaneous thrombus formation in cerebral aneurysms.

We propose a new numerical model to describe thrombus formation in cerebral aneurysms. This model combines CFD simulations with a set of bio-mechanical processes identified as being the most important to describe the phenomena at a large space and time scales. The hypotheses of the model are based on in vitro experiments and clinical observations. We document that we can reproduce very well the shape and volume of patient specific thrombus segmented in giant aneurysms.

An immunological method to combine the measurement of active and total myeloperoxidase on the same biological fluid, and its application in finding inhibitors which interact directly with the enzyme.

Myeloperoxidase (MPO) is a pro-oxidant enzyme involved in inflammation, and the measurement of its activity in biological samples has emerged essential for laboratory and clinical investigations. We will describe a new method which combines the SIEFED (specific immunological extraction followed by enzymatic detection) and ELISA (ELISAcb) techniques to measure the active and total amounts of MPO on the same human sample and with the same calibration curve, as well as to define an accurate ratio between both the active and total forms of the enzyme. The SIEFED/ELISAcb method consists of the MPO extraction from aqueous or biological samples by immobilized anti-MPO antibodies coated onto microplate wells. After a washing step to eliminate unbound material, the activity of MPO is measured in situ by adding a reaction solution (SIEFED). Following aspiration of the reaction solution, a secondary anti-MPO antibody is added into the wells and the ELISAcb test is carried out in order to measure the total MPO content. To validate the combined method, a comparison was made with SIEFED and ELISA experiments performed separately on plasma samples isolated from human whole blood, after a neutrophil stimulation. The SIEFED/ELISAcb provides a suitable tool for the measurement of specific MPO activity in biological fluids and for the estimation of the inhibitory potential of a fluid. The method can also be used as a pharmacological tool to make the distinction between a catalytic inhibitor, which binds to MPO and inhibits its activity, and a steric inhibitor, which hinders the enzyme and prevents its immunodetection.

Intracranial Aneurysms: Wall Motion Analysis for Prediction of Rupture.

Intracranial aneurysms are a common pathologic condition with a potential severe complication: rupture. Effective treatment options exist, neurosurgical clipping and endovascular techniques, but guidelines for treatment are unclear and focus mainly on patient age, aneurysm size, and localization. New criteria to define the risk of rupture are needed to refine these guidelines. One potential candidate is aneurysm wall motion, known to be associated with rupture but difficult to detect and quantify. We review what is known about the association between aneurysm wall motion and rupture, which structural changes may explain wall motion patterns, and available imaging techniques able to analyze wall motion.

Rational drug design applied to myeloperoxidase inhibition.

Rational drug design is a general approach using protein-structure technique in which the discovery of a ligand can be driven either by chance, screening, or rational theory. Myeloperoxidase (MPO) was rapidly identified as a therapeutical target because of its involvement in chronic inflammatory syndromes. In this context, the research of MPO inhibitors was intensified and development of new chemical entities was rationally driven by the research of ligands that enter into the MPO catalytic pocket. Actually, as soon as crystallography data of MPO have become available and its structure was virtually designed, the rational drug design has been applied to this peroxidase. Pharmaceutical industries and academic laboratories apply rational drug design on MPO by either optimizing known inhibitors or searching new molecules by high-throughput virtual screening. By these ways, they were able to find efficient MPO inhibitors and understand their interactions with the enzyme. During this quest of MPO inhibition, it appears that Glu268 is a crucial residue in order to optimize ligand-target interaction. This amino acid should be carefully considered by medicinal chemist when they design inhibitors interfering with MPO activity.

Myeloperoxidase and its products in synovial fluid of patients with treated or untreated rheumatoid arthritis.

OBJECTIVE: Plasma and synovial myeloperoxidase (MPO) and its products were strongly associated with osteoarthritis (OA) and rheumatoid arthritis (RA). In addition, it is well known that there is a link between oxidative stress and cytokines. The present study aims at investigating the link between synovial MPO (and its products), interleukin (IL)-18, which is involved in the degradation of articular cartilage in RA, and IL-8, which is involved in recruitment and activation of neutrophils during inflammation. Effects of the treatment of RA on the biological parameters were also investigated. METHODS: Patients (n = 105) were studied including 39 patients with OA, 33 with RA and 33 with RA receiving a specific treatment. Disease activity score (DAS-28) was calculated whereas MPO antigen/activity, neutrophils, chloro-tyrosine (Cl-Tyr), homocitrulline (Hcit), IL-8, and IL-18 were measured in synovial fluid (SF) and CRP was measured in serum. RESULTS: DAS-28 and CRP levels were not significantly different between groups. MPO activity, and MPO, Cl-Tyr, and Hcit levels were significantly higher in SF of RA patients than OA patients. MPO specific activity (MPO activity/antigen ratio) was significantly lower in treated than in untreated RA patients as was IL-8. MPO activity and concentration were correlated with IL-8 and IL-18 in untreated but not in treated RA patients. CONCLUSIONS: MPO level is related to IL-8 and IL-18 levels in untreated RA patients. A link has been shown between treatment and decrease of IL-8, MPO specific activity and Hcit in SF. The causal role of MPO in SF inflammation and how treatment can affect MPO specific activity need further investigations.

Neck and mediastinal node dissection in pharyngolaryngeal tumors.

INTRODUCTION: The present study sought to determine the necessity and prognostic impact of superior mediastinum (SM) dissection in advanced upper aerodigestive tract squamous cell carcinoma (SCC). METHODS: A retrospective review was made of the records of 31 patients who had undergone (pharyngo-) laryngectomy for advanced SCC. Statistical analysis examined correlations between the presence of SM lymph node metastasis and clinical factors, with a significance threshold of P<0.05. RESULTS: Positive cervical and/or SM lymph nodes were found in 20 cases, including six with isolated positive SM nodes. Positive SM nodes were found in none of the patients with laryngeal SCC, versus six of the 13 patients with hypopharyngeal SCC, where they were associated with tumors greater than 35 mm. Presence of paratracheal lymph node metastasis showed a strong but not statistically significant association with the primary site (larynx vs. hypopharynx: P=0.08). CONCLUSIONS: In the present series, advanced laryngeal carcinoma was never associated with positive SM nodes, whereas advanced hypopharyngeal carcinoma showed a trend in favor of paratracheal lymph node involvement.

Is there a rationale for the chronic use of phosphodiesterase-5 inhibitors for lower urinary tract symptoms secondary to benign prostatic hyperplasia?

OBJECTIVES: To critically review the physiological roles of phosphodiesterase-5 (PDE5), to explain and support the putative impact and clinical significance of PDE5 inhibitors (PDE5-Is) in the treatment of lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH) and erectile dysfunction (ED), both highly prevalent in men aged > or =50 years, as PDE5-Is are very effective as a first-line therapy for ED, and attractive for further physiological functional investigations. METHODS: We searched Medline for peer-reviewed articles in English, from 1991 to 2008, to provide a critical contemporary review of PDE5 pertaining to the potential interest of findings supporting a role for PDE5-Is in LUTS due to BPH. The selection of papers was based on the relevance of subject matter. A critical analysis of available fundamental and clinical data is reported. RESULTS: Several studies assessed the role of the nitric oxide/cGMP signalling pathway in the regulation of the prostate tone, with the support of clinical observations. PDE5-Is can also represent a potential mode of action allowing the targeting of transcriptional activity implicated in the regulation of the progression of the inflammatory process involved in BPH. PDE5-Is can inhibit human stromal cell proliferation of the prostate mediated by cGMP accumulation. New targeting hypotheses of pathophysiological processes are also reported. CONCLUSIONS: There is evidence that LUTS and ED are strongly linked. This analysis of the regulatory basis of PDE5 biology could indicate several directions of investigation. However, it is necessary to devise well-designed large prospective studies that would produce significant data before this approach becomes a standard of care.

[Decrease ApoB/ApoA-1 ratio and cardiovascular risk improvement: a tadalafil pleiotropic effect? Preliminary study on healthy volunteers]. / Diminution du rapport ApoB/ApoA-1 et amélioration du risque cardiovasculaire : effet pleïotropique du tadalafil ? Etude préliminaire sur volontaires sains.

OBJECTIVES: Recognition of erectile dysfunction (ED) as an early sign of systemic cardiovascular disease offers an opportunity for prevention. Cardiac risk assessment may deserve measurement of Apolipoprotein B/Apolipoprotein A-1 ratio. An elevated ApoB/ApoA-1 ratio is a risk factor for future coronary artery disease. ApoA-1 production, which is recognized as a cardioprotective lipid fraction, is down regulated by NFkappaB activation in vitro. Because inhibition of phosphodiesterases (PDEs) 5, 6 and 9 negatively attenuates NFkappaB translocation/activation, tadalafil, a selective PDE 5 inhibitor used for treatment of ED could present some interesting pleiotropic effects. The objective of this open study is to test the hypothesis that tadalafil treatment could decrease serum ApoB/ApoA-1 ratio. MATERIAL AND METHODS: Ten healthy men without any complain of ED or known cardiovascular risk factors were administered tadalafil 10mg intake on alternate days for 4 weeks. Lipid profile with total cholesterol, HDL-cholesterol, LDL-cholesterol, triglycerides, ApoA-1 and ApoB, was assessed at baseline (T0), after 2weeks (T1), at the end of the treatment period (T2) and after 2weeks of wash-out follow-up (T3). RESULTS: ApoB/ApoA-1 ratio was significantly decreased during treatment (mean+/-SEM, T0: 0.80+/-0.11, T1: 0.64+/-0.06, T2: 0.65+/-0.06; p<0.05) and remained lower after wash-out (T3: 0.67+/-0.05; p=0.08). Serum ApoA-1 (mg/dl) increased but not significantly during the treatment period (15.2+/-8.8, 16.5+/-7.9, 16.9+/-6, 15.3+/-7, p=0.26) and ApoB (mg/dl) significantly decreased (11.7+/-10.8, 10.3+/-8.4, 10.6+/-9.9, 10.2+/-8.6, p=0.03). HDL and LDL cholesterol were unchanged. CONCLUSION: This preliminary study showed the interest of PDE 5 inhibitors to decrease the cardiac risk factor ApoB/ApoA-1 ratio. Randomised controlled studies with longer follow-up are needed to confirm those results.

[The Arab medicine and the way of teaching it in the Golden Age. al-Râzî, one of the best representatives!]. / La médecine arabo-musulmane et son enseignement aux siècles d'or, l'exemple d'al-Râzî, l'un de ses meilleurs représentants!

In the collective psyche, the Arabs only passed the inheritance of the Greek medicine on to the Western countries. In fact, they were great developers and great discoverers. The Arab contribution in medicine was not just technical but also conceptual. The aim of this work is to describe a part of that contribution regarding the organization and the teaching of medicine and to introduce one of its best representatives, al-Râzî.

Assessment of erythrocyte shape by flow cytometry techniques.

BACKGROUND: Red blood cell (RBC) rheology is altered in different diseases, including acute conditions such as patients in intensive care units (ICU) with sepsis or with an inflammatory reaction due to postoperative states or intracerebral haemorrhage, or chronic conditions such as diabetes mellitus or terminal renal failure. Several techniques are available to assess alterations in RBC rheology, especially deformability, but they are too cumbersome to be used on a large number of cells. OBJECTIVE: To develop a new, rapid flow cytometry technique for easy assessment of RBC shape in patients. METHODS: In flow cytometry, healthy human RBC shape shows a bimodal distribution related to the biconcave form. On this histogram, the second Pearson coefficient of dissymmetry (PCD) representing the asymmetry of this histogram and the spherical index (M2:M1) were calculated, both representing the spherical shape. This technique was used in healthy volunteers (n=17) and in diseases characterised by abnormalities in RBC rheology, including terminal renal failure requiring haemodialysis (n=28), diabetes mellitus (n=18), sepsis (n=19) and acute inflammatory states (postoperative, intracerebral haemorrhage, chronic obstructive pulmonary disease, epilepsy or severe drug intoxication; n=21). Multivariate analysis was performed to determine the factors influencing RBC shape. RESULTS: Measurement of RBC shape was highly reproducible. A good correlation was observed between the PCD and the spherical index, except in the critically ill patients without sepsis. RBCs were more spherical in patients with terminal renal failure (PCD -0.56 (0.14), p<0.05), diabetes mellitus (PCD -0.59 (0.23), p<0.05), sepsis (PCD -0.58 (0.22), p<0.05) or an acute inflammatory state (PCD -0.65 (0.29), p<0.05) than in healthy volunteers (PCD -0.89 (0.12)). The spherical index was also increased in all populations compared with healthy volunteers (terminal renal failure 2.30 (0.20); diabetes mellitus 2.27 (0.38); sepsis 2.28 (0.37); acute inflammatory state 2.35 (0.42) vs healthy volunteers 2.72 (0.47); all p<0.05). Multivariate analysis demonstrated that the underlying pathology (sepsis, acute inflammatory state, diabetes mellitus, terminal renal failure) was the principal cause of these RBC shape abnormalities. CONCLUSION: RBCs are characterised by an increased spherical shape in many disease states. The measure of the second PCD in flow cytometry is a new, easy method to investigate RBC shape in various diseases. This technique could facilitate the investigation of abnormalities of RBC rheology.

Decreased immunoreactive maspin expression in intermediate thickness and thick primary melanoma lesions.

Maspin is a member of the serpin family of protease inhibitors. It is a 42 kDa cytoplasmic protein that is reported to have tumour suppressor activity. The loss of maspin gene expression is correlated with increased invasiveness and the risk of metastases in breast cancer. We studied maspin expression in primary melanoma lesions obtained from 76 patients. Immunostaining of 5 pm sections for maspin expression was obtained using the citrate antigen retrieval method. The extent of immunostaining was scored by recording the proportion of immunoreactive cells and the intensity of immunostaining. Our results demonstrated that maspin expression was down-regulated in intermediate thickness and thick melanoma lesions compared with thin lesions. These results suggest that loss of maspin expression might play a role in melanoma progression, invasion and metastatic dissemination. Further studies are needed to clarify the clinicopathological significance of maspin expression in melanoma.

Antigens and granularity of blood monocytes in relation to inflammatory markers and lipids in postmenopausal women.

OBJECTIVES: The menopause is associated with an increase of inflammatory markers (C-reactive protein, fibrinogen), cytokines (INFgamma, TNF, etc.) and blood lipoproteins. In vitro, CRP, LDL and fibrinogen can modulate or potentiate interleukines production by monocytes. The aim of this work was to study, the relationships in vivo between hs-CRP, fibrinogen, lipoproteins and the phenotype of circulating monocytes. METHODS: The monocytes phenotype, in postmenopausal women (n=26) without history of cardiovascular disease, was determined, by flow cytometry, measuring granularity and CD14, HLA-DR and CD62-L antigens expression. Blood monocytes were divided in CD14+dim monocytes (low CD14 expression) and CD14+bright monocytes (high CD14 expression). RESULTS: HLA-DR was negatively correlated with hs-CRP and fibrinogen. The relationships between ApoB, LDL/ApoB ratio and CD14 expression was restricted to the CD14+bright monocytes. Blood lipids, i.e. total cholesterol, LDL-c and ApoB were correlated with the granularity of both subsets. CD14+dim monocytes were characterized by a low granularity and CD62-L expression. CONCLUSIONS: Our data show that fibrinogen and hs-CRP are correlated with a reduced antigen-presenting capacity. Expression of CD14 on CD14+bright monocytes is negatively associated to atherogenic LDL. Blood monocytes granularity was positively correlated with serum lipids indicating that monocytes could uptake modified LDL in circulation and not restricted to subendothelial space.

High serum galectin-3 in advanced melanoma: preliminary results.

BACKGROUND: Galectin-3 (Gal-3) is a member of the family of beta-galactoside-binding mammalian lectins, and has been implicated in tumour invasion and metastatic process in vitro and in vivo. AIM: To determine whether an increase in serum Gal-3 production could be found in patients with advanced metastatic melanoma. METHODS: We collected 18 sera from patients with AJCC stage IV metastatic melanomas and 20 sera from healthy volunteers. Determination of Gal-3 was performed by ELISA, and in the group of patients with melanoma, these results were compared with the serum lactate dehydrogenase (LDH) and the C-reactive protein (CRP) concentrations. RESULTS: Gal-3 concentration was shown to be significantly higher in the group of patients with melanoma compared with healthy volunteers, and Gal-3 concentration was significantly correlated with both LDH and CRP in the melanoma group. We also selected four patients in the melanoma group for Gal-3 retrospective immunostaining analysis on cutaneous metastases. Two of these patients, who had a higher Gal-3 serum level, showed more intense staining and the other two patients, with a lower serum level of Gal-3, had moderate immunostaining, suggesting that at least part of serum Gal-3 might be produced by metastatic melanoma tissue. CONCLUSIONS: Gal-3 might play a role in melanoma progression and/or inflammation, and warrants further study.

Oxidation of low density lipoproteins by myeloperoxidase at the surface of endothelial cells: an additional mechanism to subendothelium oxidation.

The present paradigm of atherogenesis proposes that low density lipoproteins (LDL) are trapped in subendothelial space of the vascular wall where they are oxidized. Myeloperoxidase (MPO) plays a key role in oxidative damage. We propose that LDL oxidation by myeloperoxidase (Mox-LDL) could occur at the surface of the endothelial cells and not restricted to the subendothelial space. The triad constituted by endothelial cells, circulating LDL and MPO in close interaction, constitutes a synergic mechanism for the genesis of Mox-LDL.

Monoclonal antibodies against LDL progressively oxidized by myeloperoxidase react with ApoB-100 protein moiety and human atherosclerotic lesions.

Oxidized-LDL are involved in atherosclerosis pathogenesis, while the production of anti-ox-LDL monoclonal antibodies is critical for the development of diagnostic tools. This work reports the production of four monoclonal antibodies raised against human LDL, oxidized at different levels by the myeloperoxidase system. Characterization of these monoclonal antibodies showed that they do not cross-react with neither native LDL, VLDL nor hydrogen peroxide or Cu(2+)-oxidized LDL. Three of these antibodies recognize an epitope restricted to the protein moiety of mildly oxidized LDL, whereas the fourth antibody was partly dependent on the lipid presence of strongly oxidized LDL. All the antibodies were shown to react with human atherosclerotic lesions.

Effects of sample temperature on red blood cell shape in septic patients.

Several recent in vitro studies have observed that alterations in red blood cell (RBC) rheology depend on sample temperature. This possibility could limit the in vivo validity of the assessment of RBC shape. We investigated the effects of sample temperature on RBC shape estimated by flow cytometry in septic patients compared with those of volunteers. 0.5 ml of blood was placed at 4 degrees C, room temperature (20 degrees C) or at 37 degrees C. RBCs were analyzed at 30 minutes (T30) by flow cytometry and results compared to baseline measures. With the flow cytometry technique, the RBC shape of healthy volunteers shows a bimodal distribution related to the biconcave form. On this histogram, we calculated the second Pearson coefficient of dissymmetry--PCD--representing the asymmetry of this histogram. At baseline, RBC PCD was increased in septic patients representing a more spherical shape compared to volunteers (-0.73+/-0.18 versus -0.95+/-0.05; p=0.007). For both groups, RBC shape estimated by the flow cytometry technique was not modified by the temperature of the sample. We conclude that estimation of RBC shape by flow cytometry is not influenced by the temperature of the sample. The present study validates the flow cytometry technique to assess RBC shape in vitro.