Functional properties of human platelets derived in vitro from CD34+ cells.

The in vitro production of blood platelets for transfusion purposes is an important goal in the context of a sustained demand for controlled products free of infectious, immune and inflammatory risks. The aim of this study was to characterize human platelets derived from CD34+ progenitors and to evaluate their hemostatic properties. These cultured platelets exhibited a typical discoid morphology despite an enlarged size and expressed normal levels of the major surface glycoproteins. They aggregated in response to ADP and a thrombin receptor agonist peptide (TRAP). After infusion into NSG mice, cultured and native platelets circulated with a similar 24 h half-life. Notably, the level of circulating cultured platelets remained constant during the first two hours following infusion. During this period of time their size decreased to reach normal values, probably due to their remodeling in the pulmonary circulation, as evidenced by the presence of numerous twisted platelet elements in the lungs. Finally, cultured platelets were capable of limiting blood loss in a bleeding assay performed in thrombocytopenic mice. In conclusion, we show here that cultured platelets derived from human CD34+ cells display the properties required for use in transfusion, opening the way to clinical trials.

Analysis of four-fragment fractures of the proximal humerus: the interest of 2D and 3D imagery and inter- and intra-observer reproducibility.

The treatment of the four-part fractures of the proximal humerus remains a therapeutic challenge. The decision-making is based on preoperative criteria concerning the displacement of the fracture, the stability of the fracture and the risk of avascular necrosis of the humeral head. The aim of this study was to analyse the inter- and intra-observer reproducibility of those criteria previously described by Hertel. Three observers analysed three times 20 radiologic files comprising 2D X-rays, 2D CT scan and 3D reconstructions for the intra-observer study, and an expert committee was used to assess the inter-observer reproducibility. The Kappa coefficient was used to measure agreement. The Kappa coefficient founded poor to moderate agreement for the majority of the criteria after the 2D X-ray analysis. This coefficient was improved with the use of 2D CT scan and 3D reconstructions, in particular for the medial hinge assessment, the humeral head fracture and the metaphyseal extension. The reproducibility of the criteria described by Hertel on 2D X-rays is at least moderate. Reproducibility could be considerably improved by associating 2D scans and 3D reconstruction, in particular for the criteria related to prognosis for the vascularisation of the humeral head.

Lentiviral gene rescue of a Bernard-Soulier mouse model to study platelet glycoprotein Ibß function.

UNLABELLED: Essentials A signaling role of glycoprotein (GP)Ibß is postulated but not formally demonstrated in platelets. Lentiviral-mediated rescue in knock-out mice can be used to evaluate GPIbß function in vivo. Transduction of the native subunit corrected the main defects associated with GPIb-IX deficiency Deletion of intracellular 159-170 segment increased thrombosis, 150-160 removal increased bleeding. SUMMARY: Background The platelet glycoprotein (GP)Ib-V-IX complex is required for normal hemostasis and megakaryopoiesis. A role in GPIb-dependent responses has been ascribed to the less well characterized GPIbß subunit using a specific antibody and GPIb-IX transfected cells. Objectives Our aim was to evaluate, in vivo, the role of the GPIbß in hemostasis and thrombosis. Methods GPIbß(null) Sca-1(+) progenitors transduced with viral particles harboring hGPIbß were transplanted into lethally irradiated GPIbß(-/-) recipient mice. Results hGPIbß transplanted into the bone marrow of GPIbß(null) mice rescued GPIb-IX expression in 97% of circulating platelets. These platelets efficiently bound von Willebrand factor (VWF) and extended filopodia on a VWF matrix, demonstrating the restoration of GPIb-dependent adhesive and signaling properties. These mice exhibited less severe macrothrombocytopenia and had normal tail bleeding times as compared with GPIbß(null) mice. This strategy was employed to manipulate and evaluate the role of the GPIbß intracellular domain. Removal of the membrane proximal segment (Δ(150-160) ) decreased GPIb-IX expression by 43%, confirming its involvement in receptor assembly and biosynthesis, and resulted in increased bleeding times and decreased thrombosis in a mechanical injury model in the aorta. On the other hand, deletion of the C-flanking 159-170 segment allowed normal GPIb-IX expression, VWF-dependent responses and bleeding times, but resulted in enhanced arterial thrombosis. Conclusion This pointed to a repressor role of GPIbß in thrombus formation in vivo that was not predicted in studies of heterologous cells. These results highlight the utility of this lentiviral strategy for the structure-function evaluation of GPIb-IX in platelets.

Platelets in cancer. From basic research to therapeutic implications.

Platelets are well-known for their major role in primary hemostasis and thrombosis. Cancer patients frequently manifest thrombotic events and present abnormalities in blood coagulation which appear to be linked to altered platelet function and turnover. Moreover, numerous studies indicate an intimate cross-talk between platelets and tumor growth, angiogenesis and metastatic dissemination. Finally, several experimental data and clinical trials suggest possible benefits of anti-platelet drugs on some cancers. Here, we will review the current state of basic biological research regarding the role of platelets in cancer progression. We also critically review the possible clinical applicability of some anti-platelet therapies to limit tumor growth and prevent metastatic dissemination.

When gas analysis assists with postmortem imaging to diagnose causes of death.

Postmortem imaging consists in the non-invasive examination of bodies using medical imaging techniques. However, gas volume quantification and the interpretation of the gas collection results from cadavers remain difficult. We used whole-body postmortem multi-detector computed tomography (MDCT) followed by a full autopsy or external examination to detect the gaseous volumes in bodies. Gases were sampled from cardiac cavities, and the sample compositions were analyzed by headspace gas chromatography-mass spectrometry/thermal conductivity detection (HS-GC-MS/TCD). Three categories were defined according to the presumed origin of the gas: alteration/putrefaction, high-magnitude vital gas embolism (e.g., from scuba diving accident) and gas embolism of lower magnitude (e.g., following a traumatic injury). Cadaveric alteration gas was diagnosed even if only one gas from among hydrogen, hydrogen sulfide or methane was detected. In alteration cases, the carbon dioxide/nitrogen ratio was often >0.2, except in the case of advanced alteration, when methane presence was the best indicator. In the gas embolism cases (vital or not), hydrogen, hydrogen sulfide and methane were absent. Moreover, with high-magnitude vital gas embolisms, carbon dioxide content was >20%, and the carbon dioxide/nitrogen ratio was >0.2. With gas embolisms of lower magnitude (gas presence consecutive to a traumatic injury), carbon dioxide content was <20% and the carbon dioxide/nitrogen ratio was often <0.2. We found that gas analysis provided useful assistance to the postmortem imaging diagnosis of causes of death. Based on the quantifications of gaseous cardiac samples, reliable indicators were determined to document causes of death. MDCT examination of the body must be performed as quickly as possible, as does gas sampling, to avoid generating any artifactual alteration gases. Because of cardiac gas composition analysis, it is possible to distinguish alteration gases and gas embolisms of different magnitudes.

Gas analysis of exhumed cadavers buried for 30 years: a case report about long time alteration.

Due to important alteration caused by long time decomposition, the gases in human bodies buried for more than a year have not been investigated. For the first time, the results of gas analysis sampled from bodies recently exhumed after 30 years are presented. Adipocere formation has prevented the bodies from too important alteration, and gaseous areas were identified. The sampling was performed with airtight syringes assisted by multi-detector computed tomography (MDCT) in those specific areas. The important amount of methane (CH4), coupled to weak amounts of hydrogen (H2) and carbon dioxide (CO2), usual gaseous alteration indicators, have permitted to confirm methanogenesis mechanism for long period of alteration. H2 and CO2 produced during the first stages of the alteration process were consumed through anaerobic oxidation by methanogenic bacteria, generating CH4.

Innovative method for carbon dioxide determination in human postmortem cardiac gas samples using headspace-gas chromatography-mass spectrometry and stable labeled isotope as internal standard.

A novel approach to measure carbon dioxide (CO2) in gaseous samples, based on a precise and accurate quantification by (13)CO2 internal standard generated in situ is presented. The main goal of this study was to provide an innovative headspace-gas chromatography-mass spectrometry (HS-GC-MS) method applicable in the routine determination of CO2. The main drawback of the GC methods discussed in the literature for CO2 measurement is the lack of a specific internal standard necessary to perform quantification. CO2 measurement is still quantified by external calibration without taking into account analytical problems which can often occur considering gaseous samples. To avoid the manipulation of a stable isotope-labeled gas, we have chosen to generate in situ an internal labeled standard gas ((13)CO2) on the basis of the stoichiometric formation of CO2 by the reaction of hydrochloric acid (HCl) with sodium hydrogen carbonate (NaH(13)CO3). This method allows a precise measurement of CO2 concentration and was validated on various human postmortem gas samples in order to study its efficiency.

Accuracy profile validation of a new method for carbon monoxide measurement in the human blood using headspace-gas chromatography-mass spectrometry (HS-GC-MS).

The aim of our study was to provide an innovative headspace-gas chromatography-mass spectrometry (HS-GC-MS) method applicable for the routine determination of blood CO concentration in forensic toxicology laboratories. The main drawback of the GC/MS methods discussed in literature for CO measurement is the absence of a specific CO internal standard necessary for performing quantification. Even if stable isotope of CO is commercially available in the gaseous state, it is essential to develop a safer method to limit the manipulation of gaseous CO and to precisely control the injected amount of CO for spiking and calibration. To avoid the manipulation of a stable isotope-labeled gas, we have chosen to generate in a vial in situ, an internal labeled standard gas ((13)CO) formed by the reaction of labeled formic acid formic acid (H(13)COOH) with sulfuric acid. As sulfuric acid can also be employed to liberate the CO reagent from whole blood, the procedure allows for the liberation of CO simultaneously with the generation of (13)CO. This method allows for precise measurement of blood CO concentrations from a small amount of blood (10 µL). Finally, this method was applied to measure the CO concentration of intoxicated human blood samples from autopsies.

[Does robotics improve laparoscopic radical prostatectomy in complex surgical cases?]. / Le robot améliore-t-il la prostatectomie totale laparoscopique dans les cas complexes?

UNLABELLED: The radical prostatectomy is the main treatment prostate cancer in young men. However in difficult cases, another therapeutic option is often suggested. OBJECTIVE: Evaluation of the quality of the anastomosis in complex surgical cases by comparing laparoscopic radical prostatectomy (LRP) to robotic assisted radical prostatectomy (RLRP). MATERIAL: From March 2004 to August 2009, 397 patients underwent radical prostatectomy: 176 LRP and 221 RLRP consecutively by the same surgeon. Antecedents that might have complicated dissection were analyzed: prostatic volume over 80 cc, previous inguinal hernia repair with mesh, previous pelvic surgery, body mass index over 30 and previous trans-urethral resection of prostate. RESULTS: In a preoperative mode, there was no significant difference between the two groups. A multivariable analysis of the quality of the anastomosis turned to the advantage of the robot (OR=2.56 [95 %CI: 1.28-5.25]), specifically for difficult cases (Odd Ratio=7.736 [95 %CI: 2.689-22.254]). CONCLUSION: The use of the robot improved the quality of the anastomosis for patients that might have raised technical issues.

[Erectile function after permanent prostate brachytherapy: A long term prospective study about 157 cases]. / Etude de la fonction sexuelle à long terme après curiethérapie pour un cancer localisé de la prostate.

INTRODUCTION: The objective of this study was to determine the impact of the preservation of sexual function in the long-term in patients treated with brachytherapy using a validated self-questionnaire and determine the role of different clinical and therapeutic parameters. MATERIAL AND METHOD: From December 1999 to June 2002, 157 consecutive patients treated by prostate brachytherapy have been selected for the study. A questionnaire of the EORTC "QLQ C30" assorted with the module "PR25" has been submitted before treatment and in the second quarter 2007. Hundred and twenty-eight patients returned their questionnaires (81.5 %). Statistical analysis was made with 64 patients. The median follow-up was 6 years (+/-0.57 year). The settings can interfere with sexual function were assessed: age, prostate volume, co-morbidity, adjuvant hormonal therapy, D 90, V 150 and V 240. Statistical analysis was made by way univariate ANOVA procedure and mode Chi(2) and multivariate (logistic regression), the variable being studied "conservation of sexual activity YES/NO". RESULTS: The conservation rate of sexual function was 64 %. No variable can explain the loss of sexual function is reflected statistically significant (p<0.05). The most informative variable in the statistical analysis was the D 90 but is not seen as likely by a significant lack of power (p=0.08 in univariate analysis and p=0.2 in multivariate analysis). CONCLUSION: Brachytherapy for prostate preserved sexual function in the long-term in 64 % of cases (64 patients) and is therefore an attractive alternative for patients wishing to preserve it.

[Pure laparoscopic versus robotic-assisted laparoscopic radical prostatectomy: comparative study to assess functional urinary outcomes]. / Prostatectomie totale laparoscopique standard versus laparoscopique robot-assistée : étude comparative sur les résultats fonctionnels urinaires.

PURPOSE: To compare urinary functional outcomes after LP prostatectomy or robotic assisted laparoscopic prostatectomy performed by a single surgeon regarding to his initial experience. MATERIAL: Between March 2005 and April 2007, 247 consecutive patients underwent radical prostatectomy, either by LP approach (125) or by robotic-assisted laparoscopic (RALP) approach (122). The only criteria to chose robot or not, was the Robot Da Vinci's availability. RESULTS: There was no statistical difference between the two groups in terms of preoperative characteristics. The continence rate was 83% in PL group versus 81% in RALP group. More precisely, among men wearing at least one pad, 71% of patients in PL groups wear one pad/day versus 87% of patients in RALP group. Multivariate analysis on continence appears to be in favors of RALP group (Odd Ratio 2.1 [CI: 0,86-5,48]). CONCLUSION: Incontinence appears to be less severe and frequent in the RALP group. In practice, surgeon's impression of the robot's interest is evident, but more important number of patients and longer follow-up is necessary.

[Study on the quality of life of patients suffering from localized prostate cancer treated with HIFU]. / Etude de la qualité de vie des patients ayant un cancer de prostate localisé traité par HIFU.

AIM: The treatment of prostate cancer using high intensity focused ultrasound (HIFU) is considered to be mini-invasive and normally has a low rate of morbidity. The aim of this study was to evaluate the quality of life of patients treated with HIFU. PATIENTS AND METHOD: Fifty consecutive patients whose first-line treatment was with HIFU for localized cancer of the prostate between 2003 and 2005 received the "UCLA/RAND PCI" quality of life questionnaire at preoperative stage and one year after treatment. The scores for postoperative quality of life were compared to preoperative scores and to a test population who did not have prostate cancer. RESULTS: Eighty percent of patients answered both questionnaires. 72.5% of the patients were "satisfied" or "very satisfied", 2.5% were "very dissatisfied" and 25% had no opinion. The general quality of life scores (SF-36) did not show any significant differences before and after treatment. Alterations and discomfort concerning sexual and urinary functions were statistically significant. For the digestive function, there was no difference before and after treatment; however, an increase in discomfort felt was statistically significant. CONCLUSION: The treatment of prostate cancer using HIFU is accepted well by the patient, quality of life is preserved one year later. There is significant degradation of the sexual function and more moderately of the urinary function.

[Quality of life after cystectomy: French national survey conducted by the French Association of Urology (AFU), the French Federation of Stoma Patients (FSF) and the French Association of Enterostomy Patients (AFET) in patients with ileal conduit urinary diversion or orthotopic neobladder]. / Qualité de vie après cystectomie: enquête nationale de l'Association française d'urologie (AFU), la Fédération des stomisés de France (FSF) et de l'Association française des entérostomathérapeutes (AFET) chez des patients ayant eu une dérivation urinaire cutanée non continente ou un remplacement vésical orthotopique.

OBJECTIVE: National multicentre study based on specific self-administered quality of life questionnaires in patients with Bricker ileal conduit urinary diversion or orthotopic neobladder. MATERIAL AND METHOD: Questionnaires were distributed by three associations (FSF, AFU, AFET) and comprised general questions and questions specific to the type of diversion. A disability score was also included. RESULTS: Between September 2003 and March 2004, out of a total of 5739 questionnaires, 909 were returned and 877 were analysed: 738 patients with Bricker ileal conduit and 139 with orthotopic neobladder. The two populations differed at the time of the study (Bricker: 69% of men with a mean age of 70 years, orthotopic neobladder: 95.7% of men with a mean age of 64 years). The mean interval since the operation was seven years. Ninety-four percent of patients with Bricker ileal conduit and 93% of patients with orthotopic neobladder were satisfied or very satisfied with the diversion, despite mean disability scores of 5.2+/-3.7 and 3.1+/-3.6, respectively. A correlation between this score and patient satisfaction (Wilcoxon: p<0.0001) was only observed for patients with a Bricker ileal conduit. This score was significantly related to the presence of urinary incontinence with the two types of diversion. Incontinence was frequent (16.1% with Bricker ileal conduit) and 78% of patients feared episodes of incontinence, mainly due to the appliance. Daytime incontinence was frequent for 18.1% of patients with orthotopic neobladder and 40% of patients used at least one protection per day. Out of the patients with neobladder, 82.6% experienced nocturnal incontinence, interfering with sleep in 31.9% of cases. Sexual disorders and altered bowel habit (40%) were very frequent. Stoma-therapy management was insufficient for Bricker ileal conduit and exceptional after bladder replacement. CONCLUSION: Cystectomy with either ileal conduit urinary diversion or orthotopic neobladder alters many aspects of the patient's life, but patients finally accept and adapt to their new way of life.

[Effects of oral cannabis and dronabinol on driving capacity]. / Effets du cannabis oral et du dronabinol sur la capacité à conduire.

Two retrospective epidemiologic studies have shown that cannabis is the main psychoactive substance detected in the blood of drivers suspected of driving under the influence of psychotropic drugs. An oral administration double-blind crossover study was carried out with eight healthy male subjects, aged 22 to 30 years, all occasional cannabis smokers. Three treatments and one placebo were administered to all participants at a two week interval: 20 mg dronabinol, 16.5 mg D9-tétrahydrocannabinol (THC) and 45.7 mg THC as a cannabis milk decoction. Participants were asked to report the subjective drug effects and their willingness to drive under various circumstances on a visual analog scale. Clinical observations, a psychomotor test and a tracking test on a driving simulator were also carried out. Compared to cannabis smoking, THC, 11-OH-THC and THC-COOH blood concentrations remained low through the whole study (<13.1 ng THC/mL,<24.7 ng 11-OH-THC/mL and<99.9 ng THC-COOH/mL). Two subjects experienced deep anxiety symptoms suggesting that this unwanted side-effect may occur when driving under the influence of cannabis or when driving and smoking a joint. No clear association could be found between these adverse reactions and a susceptibility gene to propensity to anxiety and psychotic symptoms (genetic polymorphism of the catechol-O-methyltransferase). The questionnaires have shown that the willingness to drive was lower when the drivers were assigned an insignificant task and was higher when the mission was of crucial importance. The subjects were aware of the effects of cannabis and their performances on the road sign and tracking test were greatly impaired, especially after ingestion of the strongest dose. The Cannabis Influence Factor (CIF) which relies on the molar ratio of active and inactive cannabinoids in blood provided a good estimate of the fitness to drive.

Forensic evaluation of the QIAshredder/QIAamp DNA extraction procedure.

The potential to recover genetic profiles from evidence samples has substantially increased since robust and sensitive amplification kits are commercially available. Nevertheless, even the best amplification kits cannot succeed when the extracted DNA is of poor quality. In this study we compared the efficiency of silica (QIAamp DNA Mini Kit), Chelex and Phenol-Chloroform (PC) based protocols to recover DNA from different categories of samples (blood and saliva on cotton swabs, muscles, cigarette butts, saliva on foods and epidermal cells on clothes). The efficiency of the QIAamp system was improved when samples were treated with QIAshredder homogenizing columns. Overall, conventional Chelex or PC protocols allowed to recover conclusive SGM Plus profiles for 61% of the samples considered in this study. Contrastingly, 82% of them were successfully genotyped after being treated with a combination of QIAshredder and QIAamp systems. Our results further suggested that the QIAshredder/QIAamp protocol was particularly helpful to analyze evidence samples with few DNA and/or that were collected on substrates containing PCR inhibitors.

[Prostate cancer. Epidemiology. Risk factors. Pathology]. / Cancer de la prostate. Epidémiologie. Facteurs de risques. Anatomopathologie.

Prostate cancer (prostate adenocarcinoma) has become an important concern in terms of public health these past fifteen years; recent French epidemiological data revealed 10,104 deaths due to this disease in 2000. The two main factors involved are the serum prostatic specific antigen (PSA), routinely used since late 1980's and which allows early diagnosis (before symptom onset), and the lengthened duration of life. Such cancer is rare before the age of 50, but its frequency increases with age, making it the most frequent type of cancer in French men. Although the aetiology of this disease is unknown, the ethnic origin, and a familial history of prostate or breast cancer are known risk factors. Predisposing genes to such hereditary types remain to be identified. Other genetic factors (polymorphisms), combined with environmental factors such as nutrition, have been incriminated, which is likely to explain the geographical variations of this affection. At the molecular level, the mechanisms involved in the tumoral initiation and progression remain unclear. Various genetic alterations have been identified among the genome of cancerous cells, at various stages of the affection: intraepithelial neoplasia, localized, locally advanced, metastatic or hormone refractory stage -, hormonal escape). However, the precise sequence and nature of the complex molecular events remain to be determined prior to their routine utilisation in the determination of subjects at risk, or as prognostic factors, and even as therapeutic targets. The anatomopathology is a key for the diagnosis. Intraepithelial neoplasia is the pre-cancerous lesion observed in most adenocarcinomas; these are localized in the peripheral part of the prostate gland in 70% of the cases. Gleason's classification is the current gold standard for the determination of tumoral aggressiveness and categorisation of the adenocarcinomas which are basically heterogeneous (coexistence of tumors cells with different degrees of differenciation in the same tumor). This anatomopathological classification allows distinguishing the tumours in terms of potential progressiveness and prognosis, and hence, to orientate the therapeutic strategy in case of localised or locally advanced prostate cancer.

[Prostate cancer: Diagnosis and staging]. / Cancer de la prostate. Diagnostic et bilan d'extension.

The discovery and the use of serum prostate specific antigen (PSA) has considerably improved the diagnosis of prostate cancer during the past 20 years. Before PSA era, early diagnosis was only based on the digital rectal examination (DRE) of which the Limitations have been evidenced; over half of the tumours diagnosed by such means had already spread out of the prostate and were incurable. Assessment of serum PSA has allowed the diagnosis to be made at an earlier stage of the disease, curable by current treatments. Whichever the diagnostic tools, transrectal ultrasound (TRUS) prostatic biopsies remain necessary for diagnosis ascertainment, taking into account the low specificity of PSA assessment. The feasibility of a diagnosis at an early and curable stage of the disease has logically resulted in screening procedures aimed at reducing the high mortality related to prostate cancer. The numerous publications on prostate cancer screening provide precise information on the accuracy of available diagnostic means (PSA, DRE, TRUS, combined PSA and DRE), on the characteristics of screened tumours (stage and differentiation), and also on the population of men likely to benefit from the screening (age at beginning and end of the screening, frequency of PSA testing, identification of the men with ethnic and/or genetic predisposition). In those early diagnosed prostate cancers, the assessment of loco-regional cancer extension (extracapsular and/or, microscopic nodal involvement), remains unsatisfactory because no imaging technique (ultrasonography, CT scan, MRI,...) allows visualising the tumour itself or microscopic metastases. Nevertheless, the combination of multiple parameters such as DRE data, PSA level, biopsy data and tumour differentiation helps approaching with an increasing precision (nomograms) the true pathologic stage of the disease. Such advances allow distinguishing, among the very heterogeneous group of prostate cancers, tumours that differ from one to another in terms of disease stage, progression and prognosis, which is helpful for the determination of an adapted therapeutic strategy.

[Prostate cancer. Treatment]. / [Cancer de la prostate. Traitement]

The discovery and the utilisation of the prostate specific antigen (PSA) that allows early diagnosis of prostate cancer, have considerably improved the management of this disease. Before the PSA era, prostate cancer was just a disease of the old man, generally detected at an advanced stage and incurable, with a fatal outcome delayed by the androgenic deprivation. Since early 1990's, prostate cancer has become primarily a disease of the man of 60 years, detectable earlier, and curable provided no extraprostatic dissemination has occurred. Early treatment of prostate cancer has benefited from important advances in surgical and radio-therapeutic techniques (conformational irradiation, brachytherapy), with, as principal goal, the combination of a better survival and the reduction of the potential adverse effects that alter quality of life. A better definition of the characteristics of the tumours in terms of progression regarding various parameters (clinical stage, PSA, tumoral differentiation) have resulted, despite the heterogeneity of the disease, in the determination of subgroups of tumours with different prognosis, which leads to an improved therapeutic strategy. The assessment of men's life expectancy (< or > 10 years) is the second primary parameter on which is based the indication for curative or non curative therapy in case of localized tumour. Roughly, before the age of 75, a curative therapy is indicated whereas after this age a surveillance is reasonable as first-line treatment, followed by hormone therapy in case of onset of symptoms indicating some progression of the disease (urinary symptoms, bone lesion). At a Later stage, in case of a metastatic or locally advanced cancer, hormone therapy by androgenic deprivation is highly indicated. The hormone sensitivity characterizes prostate cancer; it has been discovered more than 50 years ago by Charles Huggins (Nobel prize-winner). This hormone therapy is a palliative treatment since its efficacy is transient (ineluctable occurrence of hormone resistance in a variable time delay), but it constitutes an essential therapeutic means with a well-established efficacy. Hormone therapy has progressively improved, with the renunciation of oestrogen therapy and surgical castration which has been replaced by luteinizing hormone-releasing hormone (LH-RH) analogues, and/ or anti-androgens. Numerous works have resulted in a better rationalization of the prescription (date of treatment initiation, interest of combined androgenic deprivation, ...) but uncertainties remain, such as the therapeutic interest of intermittent treatment, or of earlier hormone therapy combined with the treatment of the primitive tumour (adjuvant hormone therapy). Finally, at the time of the hormonal escape of which the molecular mechanisms remain unclear, no therapy has proven any efficacy in survival lengthening, and the treatment remains palliative and symptomatic. Although improved knowledge of prostate cancer aetiology is expected for a real disease prevention, early diagnosis at a curable stage of the disease (by PSA assessment) remains the only means for mortality reduction.

The P2Y1 receptor plays an essential role in the platelet shape change induced by collagen when TxA2 formation is prevented.

ADP and TxA2 are secondary agonists which play an important role as cofactors when platelets are activated by agonists such as collagen or thrombin. The aim of the present study was to characterize the role of the ADP receptor P2Y(1) in collagen-induced activation of washed platelets. Inhibition of P2Y(1) alone with the selective antagonist MRS2179 prolonged the lag phase preceding aggregation in response to low or high concentrations of fibrillar collagen, without affecting the maximum amplitude of aggregation or secretion. A combination of MRS2179 and aspirin resulted in complete inhibition of platelet shape change at low and high collagen concentrations, together with a profound decrease in aggregation and secretion. Scanning electron microscopy showed that these platelets had conserved the discoid morphology typical of the resting state. A lack of shape change was also observed in aspirin-treated P2Y(1)- and G(alphaq)-deficient mouse platelets and in delta-storage pool-deficient platelets from Fawn Hooded rats. In contrast, when the second ADP receptor P2Y(12) was inhibited with AR-C69931MX, aspirin-treated platelets were still able to change shape and displayed only a moderate decrease in aggregation and secretion. In conclusion, this study provides evidence that collagen requires not only the TxA2 receptor Tpalpha, but also P2Y(1), to induce platelet shape change.