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Biomedical subjects

Jean-Pierre Kantelip

Publications and source records attributed to Jean-Pierre Kantelip.

13 recordsLinked to original sources

Can stem cells mend a broken heart?

Myocardial infarction is the leading cause of heart failure in developed countries. The therapeutic measures of today are usually not sufficient to prevent left ventricular remodelling as they fall short of actual replacement of necrotic cardiac myocytes. However, current insights into stem cell plasticity have opened up new perspectives for regenerating the infarcted heart. Recently, a wide range of stem/progenitor cell types have been used for cardiac cell therapy (CCT), including embryonic or foetal stem cells, myoblasts, and bone marrow stem cells. To date, the choice of stem cells has yet to be optimised. This review details recent experimental data and discusses the clinical potential of the various stem cell sources for CCT.

Animals↗

Serum and intraperitoneal pharmacokinetics of cisplatin within intraoperative intraperitoneal chemotherapy: influence of protein binding.

Intraperitoneal (i.p.) chemotherapy is a promising therapeutic method to improve the effectiveness of cisplatin in patients with ovarian cancer and peritoneum involvement. Intraperitoneal treatment can be intraoperatively performed just after a complete surgical resection of peritoneal tumor nodules. However, little is known regarding the pharmacokinetics of platinum during intraoperative i.p. chemotherapy (IIC). Serum and i.p. measurements of total and ultrafilterable platinum were performed to determined pharmacokinetic parameters in 11 consecutive patients who received a 2-h IIC with 50 mg/m cisplatin. Protein concentrations were determined in serum and peritoneal liquid at the same times. The cisplatin concentration required to kill OVCAR-3 human ovarian cancer cells and evaluation of cisplatin binding to proteins were determined in vitro. Platinum i.p. concentration decreased rapidly and quickly came under the cytotoxicity threshold (10 mg for 2 h). About 85% of i.p. and serum cisplatin was ultrafilterable during IIC. Platinum concentrations were closely related to protein concentrations. Due to the very low level of serum protein (almost 25 g/l), serum cisplatin binding during chemotherapy was very low (almost 25%), but increased with protein concentration recovery. These pharmacokinetic data show that a sufficient concentration to kill human ovarian cancer is not reached with a single i.p. bath containing 50 mg/m cisplatin for 2 h. A new protocol with a renewed bath and a higher cisplatin concentration is under investigation.

Aged↗

Evaluation of a sunscreen photoprotective effect by ascorbic acid assessment in human dermis using microdialysis and gas chromatography mass spectrometry.

Ultraviolet irradiation causes adverse effects like sunburn, photosensitivity reactions or immunologic suppression. The aim of this study was to evaluate the photo-protective outcome of a sunscreen cream (SPF8) by the determination of erythema indexes and the assessment of ascorbic acid and its metabolites in human dermis. These substances were used as markers of oxidative effect. Eight healthy female subjects were enrolled in this study. Two abdominal areas were exposed to solar simulated irradiation with three minimal erythema dose, one with SPF8 application and the other site without SPF8 application. Two other areas were used as control, one without SPF8 application and the other site after SPF8 application. Ascorbic acid and its metabolites (dehydroascorbic acid, threonic acid, oxalic acid and xylose) were collected from human dermis by microdialysis and assessed by gas chromatography mass spectrometry. Irradiated site without sunscreen application had significantly demonstrated lower dermis ascorbic acid concentrations and a higher erythema index than the three other sites (P < 0.05). Threonic acid, oxalic acid and xylose dermis concentrations were significantly higher in site III than in the control site I (P < 0.05). The protected-irradiated site did not show erythema formation and there was stability of ascorbic acid dermis concentrations with non-variation in its metabolites. The assessment of ascorbic acid and its metabolites in human dermis could be an efficient tool to demonstrate the oxidative process and consequently to control the efficiency of sunscreen creams against undesirable UV effects.

Adult↗

Comparison of fluorescence polarization immunoassay and high-performance liquid chromatography methods for assay of teicoplanin: can correlation be improved?

Teicoplanin is a glycopeptide indicated in serious infections due to Staphylococcus aureus and requires monitoring and dose adjustment based on measurement of trough concentration. Measurement of teicoplanin can be carried out by the fluorescence polarization immunoassay (FPIA) method or by high-performance liquid chromatography (HPLC) methods. We aimed to compare HPLC method using the sum of the peaks of A2-2, A2-3, A2-4 and A2-5 with FPIA method. Thirty-six serum samples obtained over a 6-month period from patients treated by teicoplanin were first analyzed by a HPLC method by determining both the A2-2 peak and the sum of areas of A2-2 to A2-5 and were then stored at -20 degrees C for FPIA assay. Correlation between FPIA and HPLC A2-2 methods was as: HPLC(A2-2) = 0.694FPIA - 0.892 with r(2) = 0.93. A paired t-test revealed significant differences between the results (P < 0.001). To improve the FPIA and HPLC correlation, we performed a linear regression between FPIA and the sum of A2-2, A2-3, A2-4 and A2-5 obtained in the HPLC method: HPLC(A2-2 to A2-5) = 0.953FPIA - 0.915 with r(2) = 0.96. A paired t-test did not show any significant difference between the results of the two methods (P = 0.94). These results show a better correlation between FPIA and HPLC when the sum of A2-2 to A2-5 was used for calculations. In conclusion, HPLC(A2-2 to A2-5) must be preferred to HPLC(A2-2) for the assay of teicoplanin, even if the HPLC(A2-2 to A2-5) runtime is higher than in the HPLC(A2-2) method.

Anti-Bacterial Agents↗

[Management of a patient receiving thalidomide].

THE USE OF A DRUG WITH A TEMPORARY MARKETING AUTHORISATION: Thalidomide is currently available in France for nominative or cohort use with a temporary marketing authorisation (TMA). It is only prescribed and delivered in hospital settings. SIX OFFICIAL INDICATIONS: Its current indications are principally lepromatous nodular erythema, severe aphtosis, Jessner-Kanoff's cutaneous lymphocyte infiltration, discoid lupus erythematosis, chronic graft-versus-host reactions, and relapsed and or refractory multiple myeloma (after the failure of standard therapies). In the majority of cases, thalidomide is a last resort treatment of rare pathologies. On withdrawal, it is responsible for more or less long-term recurrences of the disease that require its re-introduction. SURVEILLANCE IS CRUCIAL: The side effects induced by thalidomide must never be forgotten, notably its teratogenic effects and its often irreversible neurotoxicity. The latter limit the long-term use of thalidomide and imply strict rules for its prescription and surveillance (efficient contraception, clinical neurological examinations, electroneurophysiological controls).

Abnormalities, Drug-Induced↗

Mesenchymal progenitor cells differentiate into an endothelial phenotype, enhance vascular density, and improve heart function in a rat cellular cardiomyoplasty model.

BACKGROUND: Cellular cardiomyoplasty is a promising approach to improve postinfarcted cardiac function. The differentiation pathways of engrafted mesenchymal progenitor cells (MPCs) and their effects on the left ventricular function in a rat myocardial infarct heart model were analyzed. METHODS AND RESULTS: A ligation model of left coronary artery of Lewis rats was used. MPCs were isolated by bone marrow cell adherence. Seven days after ligation, MPCs labeled with 4',6-diamidino-2'-phenylindole were injected into the infarcted myocardium (n=8). Culture medium was injected in the infarcted myocardium of control animals (n=8). Thirty days after implantation, immunofluorescence studies revealed some engrafted cells expressing a smooth muscle phenotype (alpha SM actin+), as similarly observed in culture. Other engrafted cells lost their smooth muscle phenotype and acquired an endothelial phenotype (CD31+). Furthermore, vessel density was augmented in the MPC group in comparison with the control group. After 30 days, echocardiography showed an improvement on left ventricular performance in the MPCs compared with the control group. CONCLUSIONS: In vivo administration of syngenic MPCs into a rat model of myocardial infarcted heart was safety demonstrated. Some engrafted cells appeared to differentiate into endothelial cells and loss their smooth muscle phenotype. MPC engraftment might to contribute to the improvement on the cardiac function in such a setting.

Animals↗

A neutropenia suggesting an interaction between valacyclovir and mycophenolate mofetil.

Mycophenolate mofetil (MMF) is a drug which decreases the frequency of renal transplantation rejection. However, cytomegalovirus infections are a common feature of this treatment leading the physicians to prescribe antiviral prophylactic drugs like valacyclovir. During this association, neutropenia occur and the cause of this adverse effect is difficult to define. This report presents a case of neutropenia in a woman treated with MMF and valacyclovir. As the duration of the valacyclovir treatment exactly corresponds to the neutropenia duration, and the mycophenolate trough levels increased with the neutrophil count, the responsibility of this neutropenia was ascribed to valacyclovir. However, an examination of the literature for cases of neutropenia led to the suspicion of an interaction between MMF and valacyclovir. Mycophenolate may increase intracellular concentrations of valacyclovir up to haematotoxic levels. This mechanism may explain the interaction and further research is needed to confirm this interaction.

Acyclovir↗

Role of beta 1- and beta 2-adrenoceptor subtypes in preconditioning against myocardial dysfunction after ischemia and reperfusion.

Using an isolated nonworking rat heart model, this study investigated the role of beta-adrenergic preconditioning (beta-PC) to attenuate myocardial dysfunction after an ischemia/reperfusion injury. After a 20-min stabilization period, the noradrenaline depleted hearts were perfused for 5 min with isoproterenol (ISO) before 40-min global ischemia (I) followed by 30-min reperfusion (R). ISO 0.02 microM provided significant protection versus unconditioned in vivo reserpinized IR control, causing a decrease of creatine kinase (CK) release (mIU/min/g wet weight) on reperfusion in coronary effluent, a preservation of the mean coronary flow (MCF) and preservation of left ventricular function assessed by the rate-pressure product (RPP). These beneficial effects were similar to those of ischemic preconditioning (I-PC) in both nonreserpinized and reserpinized rats. Propranolol (1 microM) and atenolol (10 microM) completely suppressed the ISO preconditioning. In contrast, ICI 118551 (2 microM) a highly selective beta -blocker, did not blunt the salutary effects of ISO on CK release and MCF preservation. These results indicate that ISO pretreatment provides a significant cardioprotection against prolonged ischemic myocardial injury. Although endogenous catecholamines are not necessary for I-PC in isolated rat hearts, cardioprotection provided by beta-adrenergic stimulation is quite similar to I-PC. This significant cardioprotection is mediated less by beta -adrenoceptor than by beta -adrenoceptor activation, which seems to play a crucial role in the beta-PC mechanism.

Adrenergic Agonists↗

Ischaemic preconditioning and mast cell histamine release: microdialysis of isolated rat hearts.

The aim of this study was to investigate the feasibility of intramyocardium kinetics of histamine release by microdialysis in the isolated rat heart and ascertain if the inhibition of histamine release is implicated in the antiarrhythmic effect of preconditioning. A 30 min normothermic global ischaemia model followed by 30 min reperfusion was carried out in the control group (n= 9). In the preconditioning group (n= 8) there was a 5 min global ischaemia followed by 10 min of reperfusion. A mast cell stabilizing group received the disodium cromoglycate ( 10 micro M, n= 10). The last group received a mast cell degranulator, compound 48/80 (1micro g ml (-1), n= 10). In the control group, the histamine release during reperfusion was significantly different from the basal concentration ( 18.4 +/- 6.5 vs 1.9 +/- 0.5 nM, P< 0.05) and was associated with a maximal period of severe arrhythmias. The ischaemic preconditioning modified the histamine release kinetics with an early mast cell degranulation ( 9.7 +/- 1.5 nM) and a significant decrease in the total period of severe arrhythmias in comparison with the control group ( P< 0.05). In the disodium cromoglycate group, the histamine release during reperfusion decreased ( 3.1 +/- 0.7 nM) and was associated with a maximal period of severe arrhythmias. In the C48/80 group, the increase in the histamine released during reperfusion ( 21.2 +/- 5.0 nM) was associated with a maximal period of severe arrhythmias. These results showed firstly the feasibility of kinetic histamine release in myocardium interstitial fluid on the isolated rat heart and secondly that the inhibition of histamine release did not play a direct role in the antiarrhythmic effect of preconditioning.

Animals↗

Acitretin-associated thrombotic stroke.

OBJECTIVE: To report a case of thrombotic stroke. The etiology was difficult to identify, but was finally ascribed to psoriatic treatment with acitretin. CASE SUMMARY: Treatment with acitretin was prescribed for a 52-year-old white woman for long-standing psoriasis. Thirty-four days later, she developed nausea, vomiting, vertigo, and headaches, followed by left lateropulsion, which impeded standing and lying. Both neurologic examination and magnetic nuclear imaging indicated a rectangular infarct in the vermis cerebelli and a small bulbar infarct. Time-of-flight magnetic resonance angiography confirmed the presence of a thrombus at the beginning of the left vertebral artery. After heparin-based treatment and physiotherapy, the evolution was favorable. DISCUSSION: Etiology identification of the stroke included cardiogenic pathology and coagulopathy, but acitretin treatment was considered the likeliest explanation. On review of the literature, this seems to be the first case of a thrombotic event associated with acitretin. CONCLUSIONS: Acitretin should be considered as a possible cause of thrombotic stroke; this possibility should be kept in mind when patients taking acitretin develop an unexplained thrombotic event.

Acitretin↗