[Patient safety culture in neonatal intensive care units as seen by nurses]

Neonatal intensive care units (NICUs) are critical environments in terms of safety of care, with a high risk of adverse events. Measuring the patient safety culture of the professionals working there should help to improve the care offered. A descriptive cross-sectional study, conducted among 141 nurses and childcare workers in 2020 in 5 Tunisian hospitals, examined this question.

Drug interaction between carbamazepine and other antiepileptic drugs in Tunisian epileptic patients

INTRODUCTION

Carbamazepine could be used on monotherapy or associated to other antiepileptic drugs (AED). In these cases, drug interactions should be taken into account.

AIM

To assess the influence of the coadministration of CBZ with other AED on the trough plasmatic concentration (C0) of CBZ in epileptic adults.

METHODS

We performed a retrospective study over a period of 9 years in the Department of Clinical Pharmacology in the Tunisian National Centre "Chalbi Belkahia" of Pharmacovigilance. Our study included samples from adult patients receiving CBZ alone or associated to other AED for epilepsy. Trough plasma CBZ plasma concentrations were measured by an immunological method. Included samples were divided in four groups: i/ group 1 (G1) receiving CBZ as monotherapy, ii/ group 2 (G2) treated by CBZ with an enzyme inducer (phenobarbital or phenytoin), iii/ group 3 (G3) taking CBZ associated to an enzyme inhibitor (valproic acid (VPA)), iv/ group 4 (G4), treated by CBZ associated to enzyme inducer (phenobarbital or phenytoin) and enzyme inhibitor (valproic acid) at the same time.

RESULTS

There were no significant differences between different groups in age, weight and sex ratio. However statistical analysis showed a significant decrease in C0/D CBZ ratio between G1 and G2 and between G1 and G4 (p<0.001). However, the difference was not significant between G1 and G3 (p=1.2044).

CONCLUSION

It is important to check and to prevent the consequences of the interaction between CBZ and other AED in order to avoid inefficiency and toxicity.

Development and validation method for estimation paclitaxel in plasma

BACKGROUND

Paclitaxel (PTX) is an anticancer drug used in the treatment of many cancer , alone or in combination with other anti-tumors. It has a narrow therapeutic range, a large inter and intra-individual pharmacokinetic variability and haematological toxicity. The most effective pharmacokinetic parameter seems to be the time during which the plasma concentration is over 0.05 μmol/L.

AIM

To develop and validate a new method for PTX quantitation in plasma using HPLC with UV/visible detection.

METHODS

A rapid HPLC-UV method was developed for the determination of PTX level in plasma. All solvents used were HPLC grade.

RESULTS

After liquid-liquid extraction, chromatographic separation was achieved using an RP 18 (250 mm) column. The mobile phase was composed of acetonitrile and 0.1 M potassium dihyrogenophosphate (49/51) (v/v). Clonazepam was used as internal standard. This technique was linear over the range 50 ng/mL to 1500 ng/mL (r= 0.998). The evaluation of precision showed that our method is repeatable with a within-day coefficient of variation (CV) ranging from 6.94 to 18.78 % and reproducible for three studied concentrations low, medium and high with day-to-day CV of 14.92, 10.46 and 11.8% respectively. Under these conditions, each analysis required no longer than 12.81 min.

CONCLUSION

We have developed and validate a new assay for PTX monitoring using HPLC with UV detection which is sensible, specific, reliable and easy to carry out in clinical use for its therapeutic drug monitoring.

Comparative study of two techniques of mycophenolate mofetyl monitoring

INTRODUCTION

Mycophenolic acid (MPA) requires routine therapeutic drug monitoring.

AIM

To evaluate the suitability of a MPA Immunoassay CEDIA performed on Indiko® analyzer (Thermo fisher) for monitoring of MPA by comparing values obtained by HPLC-UV method.

METHODS

This study was carried out on 114 blood samples collected from renal transplant, using high performance liquid chromatography combined with ultraviolet detection (HPLC-UV, reference method) and the new immunoassay on CEDIA.

RESULTS

The assay was linear for a mycophenolic acid concentration up to 10 μg/mL. When MPA concentrations in all 114 transplant recipients obtained by the HPLC-UV (x-axis) method were compared with corresponding values obtained by the CEDIA® method (y-axis), the following regression equation was obtained: CEDIA® = 1.558 HPLC + 0.49 (r = 0.86). However more significant positive bias was observed (37 %).

CONCLUSION

The data presented suggest that the CEDIA® MPA immunoassay, run on the Indiko® analyzer, over-estimates plasma MPA concentrations. However, CEDIA® immunoassay is less laborious and time consuming than chromatographia techniques.

Multidisciplinary exams in medical studies : Interest of docimologic analysis

Docimology has allowed the development of evaluative processes assuring valid, reliable and objective assessments. It was adopted within the faculty of Medicine of Tunis since  2007. The aim of this study was to analyze the docimological survey results of hematology-oncology exams, to evaluate the interest of this analysis in the elaboration of exams and the construction of an item bank, and propose some corrections  in order to improve assessment.     Methods :We have analyzed the hematology-oncology exams of SCMS1 (Second cycle of Medical Studies 1) from educational year 2008-2009 to 2013-2014. The data input was already done with Excel. The test includes 4 disciplines (Hematology, Oncology, Genetics and the Anatomic Pathology). We have calculated docimological parameters allowing global analysis, by discipline and by item. Results : A total of 3281 papers and 1004 questions were analyzed. The average success rate per year was 91,54% ± 7,12. The highest average success rate was found in hematology (80,51% ± 10,18). The lowest rate was found in the anatomic pathology (51,61% ± 23,76). The average rate of students succeeding the test without having average note in hematology was 5,36%. It was 42,29% in the anatomic pathology. Average difficulty index was 0,57 ± 0,05. Items analysis showed that 38,04% were easy and 19,02% were difficult. Average discrimination index was 0,25 ± 0,02. Discrimination was very good in 20,51% of items and good in 17,13%. Useless and bad discrimination items were about 40,53%. The average of Cronbach Alpha coefficient was 0,84 ± 0,03, showing a good internal-consistency. Conclusion :This study allowed an objective evaluation of "contributive disciplines" in multidisciplinary evaluation and showed the interest of integrating questions. Question analysis with teachers would be important to reevaluate and improve these items.

Hypericum Humifusum Leaves Attenuates Hepatic Ischemia-Reperfusion Injury in a Rat Model

INTRODUCTION

Effective prevention strategies require specific actions during the different phases of ischemia-reperfusion (I-R) injury. The objective of our study is to evaluate the effect of aqueous extract of Hypericum humifusum leaves (HHL) on liver I-R model in Rat.

MATERIAL AND METHODS

Animals were subjected to 90 min of hepatic ischemia followed by reperfusion (120 min). HHL extract (25 mg/mL/kg) was injected 15 min before reperfusion. To evaluate the effect of HHL extract on I-R, we have monitored transaminases levels, Malondialdehyde (MDA) concentration, histological lesions (apoptosis and necrosis) and compared the results to a reference oxidant vitamin E.

RESULTS

The determination of total phenol extracts of HHL was 59.91 ± 0.35 mg of Gallic Acid/g dry plant material with higher antioxidant activity (91.73% ± 1.67) compared to vitamin E (87.42%). Using aqueous extract of HHL, we noted a significant decrease of AST and ALT [1129 UI (585/1995) and 768 UI (335/1375)] compared to no-treated group [5,585.5 UI (5,035/12,070) and 8,099.5 UI (5,040/12,326)] as a decrease in MDA content [85.7% protection (50.9/91.5)]. HHL extract reduce the damage induced by I-R of 48.7% (27/48.7) and 96.1% (95.7/96.5) for necrosis and apoptosis lesions respectively.

CONCLUSION

HHL aqueous extract have potential to protect liver from the damage effect induced by I-R better than vitamin E solution.

Therapeutic monitoring of antiepileptic drugs in comatose patients

OBJECTIVE

In this study, we aimed to analyze the trough plasmatic levels (C0) of the antiepileptic drugs (AED) administered by nasogastric tubes (NGT) in comatose patients and to draw up recommendations for therapeutic drug monitoring (TDM) and for the modalities of AED administration by NGT.

METHODS

We conducted a retrospective study on comatose patients addressed over six years and 10 months in Clinical Pharmacology for C0 measurement of AED administered by NGT.

RESULTS

In this study, the sex-ratio was 2.38 (44 patients). The patients' median age was 24 years. There was 14.5% of children (≤16 years). Among the 103 samples, C0 measurement concerned valproic acid in 57%, phenobarbital in 28 % and carbamazepine in 15%. Two AED or more were associated in 42% of patients. AED were associated to other drugs in 85% of cases. The AED C0 were subtherapeutic in 71% of cases. C0/Dp lower than recommanded in 65 %. In these samples, 55% presented at least one drug association with the concerned AED. In 45% of the cases, there was no drug association but a non-respect of modalities of AED administration by NGT in patients.

CONCLUSION

  The drug monitoring is a useful tool to assess drug-drug interactions and to control modalities of AED administration in comatose patients.

[Antiepileptic drugs administration by nasogastric tube in comatose patients]

AIM

To evaluate the modalities of administration of antiepileptic drugs (AED) with nasogastric tube (NGT) by nurses and to draw up recommendations.

METHODS

Our study consisted on investigating the modalities of administration of AED's with NGT by nurses during four months. We prepared 10 questions including demographic information. Participation was voluntary and anonymous. The questionnaire was distributed in seven intensive care departments after authorization of each head of the department. Thus, 45 nurses were included.

RESULTS

Nurses sex ratio was 1.5 and mean age was 31 years (25 to 37 years). Among the nurses, 60% mentioned that the NGT were silicone made and 4% that they were PVC made. The mean duration before replacing the NGT was thought to be 5±3 days. Among the nurses, 91% affirmed to clear the NGT after each use. All the nurses had agreed that the solid form is the most commonly used pharmaceutical form in the NGT. AED were associated with the enteral feeding solution in 56%. The AED should be crushed before administration for 98% of the nurses even in case of polymedication. Among them, 62% recommended to crush all of the associated drugs together. Before introducing the AED into the NGT, 93% of the nurses reported mixing with tap water. We have noticed that 62% of nurses felt the need to improve their knowledge AED administration with NGT.

CONCLUSION

To optimize AED therapy, modalities of administration by NGT in epileptic comatose patients should be enhanced.

Limited sampling strategy for the estimation of mycophenolic acid area under the curve in Tunisian renal transplant patients

Mycophenolate mofetil is a prodrug widely used in renal transplantation to prevent organ rejection. It is hydrolyzed to its active compound mycophenolic acid (MPA). MPA area under the curve (AUC_0-12h) is considered the best pharmacokinetic parameter for the estimation of MPA exposition and for prediction of rejection. MPA-AUC requires several blood samples, making it impractical for clinical practice. Therefore, development of a limited sampling strategy (LSS) to estimate MPA AUC_0-12h using three blood samples is very helpful for MPA individual dose adjustment. Results of LSS differ according to the patient background and to the drug formulation. Therefore, the purpose of this study was to develop a LSS for the estimation of MPA AUC_0-12h in Tunisian renal transplant patients treated with the generic formulation of mycophenolate mofetil (MMF^®, MEDIS). The best correlation was achieved by a profile based on three time points C_0.5h, C_1.5h, and C_4h after drug intake: AUC_0-12h = 0.414 + 1.210 × C_0.5 + 2.256 × C_1.5 + 4.134 × C₄ (mei = 1.65% and rmse = 5.81%). The correlation between full AUC_0-12h and abbreviated AUC_0-12h was 0.917. In conclusion, this model provides a reliable and simple equation to estimate MPA AUC_0-12h for the generic formulation of mycophenolate mofetil (MMF^®).

Fatal Kounis syndrome with stent thrombosis secondary to amoxicillin/clavulanic acid use: A case report and literature review

Anaphylactic reactions are often induced by drugs, and the most frequent ones are penicillin derivates. The concurrence of acute coronary syndrome with hypersensitivity and anaphylactic or anaphylactoid reactions constitutes the Kounis syndrome. We report a case of a coronary stent thrombosis with a fatal outcome complicating an anaphylactic shock induced by amoxicillin-clavulanic acid association. A 58-year-old woman with a history of triple coronary stenting was treated by amoxicillin/clavulanic acid association for pharyngitis. One hour after the first drug intake, she developed an anaphylactic shock with acute constricting chest pain. She received intravenous hydrocortisone and was transferred to emergency department. The patient received epinephrine intravenously with fluid perfusion and oxygen. Electrocardiogram showed Pardee waves in the anterior precordial leads. Cardiac enzyme levels (troponin I) were disturbed. The patient was transferred to the coronary care unit with a diagnosis of acute myocardial infarction. The coronary angiography revealed anterior interventricular stent thrombosis. The patient experienced a cardiogenic shock with an important hemodynamic repercussion, and she died few hours later despite emergency care. The responsibility of amoxicillin-clavulanic acid association was retained in the genesis of this anaphylactic shock in front of a suggestive delay, a compatible evolution and a high semiotic score. Amoxicillin/clavulanic acid use may cause Kounis syndrome. The use of epinephrine is a challenging decision. We suggest that Kounis syndrome should be considered in the differential diagnosis of acute coronary syndrome.

Protective effect of Ulva lactuca extract during hepatic cold preservation in rats

Introduction In recent years, many marine resources have drew attention in the research for bio-active compounds to develop new drugs and health foods. (1) Marine algae are now considered as a rich source of antioxidants (2). It is known that seaweeds contain numerous bioactive substances that have the ability to lower cholesterol, reduce blood pressure, promote healthy digestion; and antioxidant activity (3). Natural antioxidants are interesting compounds due to their properties which help prevent oxidative stress (4), among other potentially beneficial actions. For instance, several biological effects have been attributed to flavonoids, such as anti-tumoral, anti-inflammatory, anti-ischemic and anti-aggregate plaquetary activities. These activities are believed to be in part related to the antioxidant properties of the compounds, namely in scavenging radical oxygen species (ROS). (5, 6) The cold ischemia constitute a situation of oxidative stress in touch with liberation of oxygenated radicals, these situations incited the researchers to find means for the improvement of the conservation of organs allowing to prolong the durations of the cold ischemia of certain organs (in particular the liver) with conservation of the maximum functional value. However, the constant efforts led by the teams of transplantation to develop transplants, the conservation of organs remains a problem to be resolved. (7) Conservation solution of organ appears as being a stemming to remedy the fatal effects of the ischemia-reperfusion. For our part, we think that seaweeds have not delivered their secrets and yet especially that the marine environment of the Tunisian coast still remains little exploited in spite of the big variety of the fauna and the flora of the coast. We envisage in this work, to study a sort of seaweed collected on the Tunisian quotation in the region of "Chott Meriem" (North West of Tunisia). The purpose of our work is to estimate the capacity of extracts stemming from the green seaweed Ulva lactuca to improve the conservation solution of organs against the hepatic effects of ischemia.

Animal model of liver ischemia reperfusion: biochemical and histological evaluation

INTRODUCTION

During last years, significant progress was made in the comprehension of the hepatic lesions after Ischemia-Reperfusion episode in order to improve the Results in practice clinical.

AIM

To avoid or reduce the damage induced by Ischemia-Reperfusion, we developed a model of hepatic Ischemia-Reperfusion with variable periods of reperfusion from 0 to 24 hours. 

METHODS

Our study related to rats Wistar males.  Six various groups were studied: the first reference group (without neither ischemia and reperfusion), the second group with ischemia of 90 min and without reperfusion and the 3end , 4end, 5end and 6end groups in addition to ischemia, underwent a reperfusion of 30 min, 2h, 6h and 24h respectively.  The damage of hepatic Ischemia-Reperfusion was evaluated by a biochemical test based on the proportioning of transaminases and an anatomopathologic study by optical microscopy for the determination of the degree of hepatic attack. 

RESULTS

The RESULTS obtained seem to show an aggravation of the liver lesions and an increase in the plasmatic rates of AST and ALT in relation with the duration of the reperfusion.  Indeed, the maximum of damage was observed after 2 hours of reperfusion. We observed a reduction in the lesions after 6h and 24h of reperfusion. 

CONCLUSION

Our work enabled us to describe a simple model of hepatic Ischemia-Reperfusion with functional, biochemical and anatomopathologic tests.

Pharmacokinetik population of methotrexate in tunisian population with acute lymphoblastic leukemia

BACKGROUND

The use of high dose of MTX in the treatment of the leukemia is actually better controlled by renal preparation, control of plasma concentrations and administration of folinic acid. However, High dose MTX has been proven to cause substantial toxicity and have high intra-and inter-patient variability. Population pharmacokinetic analysis is a useful tool for identification of sources of pharmacokinetic variability during anticancer drug development and can aid the design of alternative dosing regimens to enhance their efficacy and safety.

AIM

The aim of our study is to developed and validate a population pharmacokinetics model of our population. We hereby describe the clinical covariates (age, sex and clearance of the creatinine) that influence MTX pharmacokinetic for predicting optimal dose to reduce MTX toxicity.

METHOD

It is a prospective study achieved between January 2005 to January 2012 in the Service of Clinical Pharmacology. Including 273 patients treated for acute lymphocytic leukaemia 2582 plasma concentration was achieved. The data have been analyzed with Nonmem© software (non linear regression to mixed effect).

RESULTS

The age of our patients varied from 2 to 23 years with an average of 13 years. The patients received high dose MTX therapy (1 to 8 g/m2) in 24 hours infusion every 15 days. Three compartiment models describe the pharmacokinetic of MTX. The most important covariables affecting the model were clearance of the creatinine, age and weight. We obtained a good correlation between the predicted and the observed concentrations.

CONCLUSION

The development of population pharmacokinetics model of MTX allows us to propose a therapeutic diagram adapted to every patient according to its morphological and pharmacological features while taking in consideration the therapeutic objective.

[Delayed convulsion after lidocaine instillation for bronchoscopy]

INTRODUCTION

Lidocaine toxicity usually appears rapidly and is directly correlated with plasma concentrations of the drug.

CASE REPORT

We report a case of a late neurologic toxicity occurring after instillation of lidocaine during fibre-optic bronchoscopy. A patient with bronchiolitis obliterans underwent a diagnostic bronchoscopy. She received multiples instillations of Xylocaine(®) 2% (lidocaine). Three and a half hours later, she had a tonic-clonic seizure. Seven hours later, this recurred. Lidocaine plasma levels were in the toxic range at the time of the first seizure (18.32μg/mL) with a significant decrease in the concentration noted 24hours later.

CONCLUSION

The slow absorption of lidocaine into the blood from the bronchial tree explains the delayed neurologic toxicity. Our observation is a reminder that complications can occur due to high doses of lidocaïne administrated by instillation. Thus, if the recommended dose of lidocaine is exceeded, it is essential to monitor patients closely for a prolonged period, especially those with fibrosing lung disease in order to avoid possible late toxicity.

[Development and validation of a new HPLC method for determination of Lamotrigine and clinical application]

BACKGROUND

Lamotrigine is an effective anticonvulsant drug used in the treatment of epilepsy. It has a narrow therapeutic range, a large inter and intra-individual pharmacokinetic variability and some concentration-dependent side effects.

AIM

The aim of this study was to develop and validate a new method for lamotrigine quantitation in plasma using HPLC with UV/visible detection.

METHODS

A rapid HPLC-UV method was developed for the determination of lamotrigine in plasma. All solvents used were HPLC grade.

RESULTS

After liquid-liquid extraction, chromatographic separation was achieved using an RP 18 (250 mm) column. The mobile phase was composed of acetonitrile and 0.1 M potassium dihyrogenophosphate (25/75) (v/v). Barbital sodium was used as internal standard. This technique was linear over the 2 μg/mL to 50 μg/mL range (r= 0.99). Detection and quantification limits were 0.07 μg/mL and 0.21 μg/mL, respectively. Within-day coefficient of variation (13.37 to 16 %) and day-to-day coefficients of variation (15.68 to 16.63 %) at three different concentrations. Under these conditions, each analysis required no longer than 10 min. We finally evaluated the plasma concentrations of lamotrigine in Tunisian patients treated with this drug.

CONCLUSION

The results found are similar to those previously described and the developed method is repeatable and reproducible. It can be used for clinical applications.

[Therapeutic Drug Monitoring of Valproic Acid in Children: A Prospective Study of The Effect of The Compliance and The Economic Level on the Trough Plasmatic Concentrations and Epileptic Seizures]

INTRODUCTION

Valproic acid (VA) is a widely used antiepileptic drug. Because of its pharmacokinetic variability and the influence of intrinsic and extrinsic factors such as the treatment compliance, VA therapeutic drug monitoring (TDM) is recommended in children. The aim of this study is to evaluate the effect of treatment compliance and the economic level on VA tough plasmatic concentration (TPC) and epileptic rhythm in children.

MATERIAL AND METHODS

A one-year prospective study (August 2008-August 2009) concerning children (age≤5 years) regularly treated by VA who had a VA TDM. So, 276 plasmatic samples from 238 children were collected. The children were divided in two groups as following: the group 1 (G1) presenting a good compliance and a reliable questioning and the group 2 (G2) presenting a bad compliance and a non reliable questioning. We evaluated the interindividual variability by correlating the TPC to the dose. Then, we divided the hole group in function of their economic levels (low-medium-high).

RESULTS

Sex ratio male/female was 1.3. Median age was 5 years+/-3,9. The mean TPC was 62 µg/mL [0.12-131 µg/mL]. VA TPC were in the therapeutic range (TR) in 62%. Adverse drug reactions were noted in 4.2% of the children. G1 represented 70% of the children and G2, 30%. The TPC were in the TR in 67% of G1 and 51% of G2 (p=0.02). There was a significant difference between the TPC in G1 and G2 (p=0.02).There was no significative difference in the TPC in function of the economic levels. There was no correlation between TPC and the administered doses. The epileptic seizures were more spaced in children with therapeutic TPC than those with TPC in the TR (p=0.002) and in G1 than in G2 (p=0.03).

CONCLUSIONS

Compliance should be appropriate in order to optimize the TDM rule. A good compliance and a therapeutic TPC allow a better control of epileptic seizures.

Population pharmacokinetics of bupivacaine in combined lumbar and sciatic nerve block

Objectives:

The primary aim of this study was to establish the population pharmacokinetic (PPK) model of bupivacaine after combined lumbar plexus and sciatic nerve blocks and secondary aim is to assess the effect of patient's characteristics including age, body weight and sex on pharmacokinetic parameters.

Materials and Methods:

A total of 31 patients scheduled for elective lower extremity surgery with combined lumbar and sciatic nerve block using plain bupivacaine 0.5% were included. The total bupivacaine plasma concentrations were measured before injection and after two blocks placement and at selected time points. Monitoring of bupivacaine was made by high performance liquid chromatography (HPLC) with ultraviolet detection. Non-linear mixed effects modeling was used to analyze the PPK of bupivacaine.

Results:

One compartment model with first order absorption, two input compartments and a central elimination was selected. The Shapiro-Wilks test of normality for normalized prediction distribution errors for this model (P = 0.156) showed this as a valid model. The selected model predicts a population clearance of 930 ml/min (residual standard error [RSE] = 15.48%, IC 95% = 930 ± 282.24) with inter individual variability of 75.29%. The central volume of distribution was 134 l (RSE = 12.76%, IC = 134 ± 33.51 L) with inter individual variability of 63.40%. The absorption of bupivacaine in two sites Ka1 and Ka2 were 0.00462/min for the lumbar site and 0.292/min for the sciatic site. Age, body weight and sex have no effect on the bupivacaine pharmacokinetics in this studied population.

Conclusion:

The developed model helps us to assess the systemic absorption of bupivacaine at two injections sites.

Vancomycin therapeutic drug monitoring in cerebrospinal fluid

Vancomycin penetrates poorly through the blood-brain barrier. Determination of vancomycin concentration in plasma is recommended. In contrast, its determination in cerebrospinal fluid (CSF) is rarely performed. We report the case of a 74-year-old man with post traumatic meningitis with vancomycin concentration measured in CSF.

CORM-3, a water soluble CO-releasing molecule, uncouples mitochondrial respiration via interaction with the phosphate carrier

Carbon monoxide is continuously produced in small quantities in tissues and is an important signaling mediator in mammalian cells. We previously demonstrated that CO delivered to isolated rat heart mitochondria using a water-soluble CO-releasing molecule (CORM-3) is able to uncouple mitochondrial respiration. The aim of this study was to explore more in depth the mechanism(s) of this uncoupling effect. We found that acceleration of mitochondrial O2 consumption and decrease in membrane potential induced by CORM-3 were associated with an increase in mitochondrial swelling. This effect was independent of the opening of the mitochondrial transition pore as cyclosporine A was unable to prevent it. Interestingly, removal of phosphate from the incubation medium suppressed the effects mediated by CORM-3. Blockade of the dicarboxylate carrier, which exchanges dicarboxylate for phosphate, decreased the effects induced by CORM-3 while direct inhibition of the phosphate carrier with N-ethylmaleimide completely abolished the effects of CORM-3. In addition, CORM-3 was able to enhance the transport of phosphate into mitochondria as evidenced by changes in mitochondrial phosphate concentration and mitochondrial swelling that evaluates the activity of the phosphate carrier in de-energized conditions. These results indicate that CORM-3 activates the phosphate carrier leading to an increase in phosphate and proton transport inside mitochondria, both of which could contribute to the non-classical uncoupling effect mediated by CORM-3. The dicarboxylate carrier amplifies this effect by increasing intra-mitochondrial phosphate concentration.

[Auditory hallucinations due to voriconazole: Illustration by plasma monitoring]

Voriconazole is a second-generation azole antifungal that is widely indicated in the treatment of invasive aspergillosis. It is generally well tolerated. It has nevertheless numerous side effects like hepatotoxicity, photosensitivity, skin rashes, and visual disturbances. Hallucinations were also reported as side effects to voriconazole but auditory hallucinations were rarely reported and seem to be related to toxic voriconazole blood levels. We report, herein, a case of auditory hallucination with monitoring of voriconazole plasma concentration during hallucination and after its disappearance. A 38-year-old man was treated with intravenously voriconazole for a pulmonary aspergillosis. Seven days after the initiation of voriconazole, the patient presented a sudden history of auditory hallucination associated to incoherence and temporo-spatial disorientation. Therapeutic drug monitoring of voriconazole showed a plasmatic residual concentration (C0) of 7.5μg/mL (therapeutic interval: 1.4-1.8μg/mL) and a pic concentration (Cmax) of 9.83μg/mL (therapeutic interval: 2.1-4.8μg/ml). Voriconazole was then stopped and, two days later, symptomatology completely disappeared and at the same time levels of voriconazole decreased (C0=0.11μg/mL and Cmax=2.17μg/mL). We concluded in our case that the patient's auditory hallucinations were caused by voriconazole treatment. In fact, the sudden onset of hallucinations was concomitant with high plasmatic voriconazole levels, and since the medication was stopped, an important decrease of voriconazole levels was observed which was associated with a sudden disappearance of the auditory hallucinations.

A carbon monoxide-releasing molecule (CORM-3) uncouples mitochondrial respiration and modulates the production of reactive oxygen species

Carbon monoxide (CO), produced during the degradation of heme by the enzyme heme oxygenase, is an important signaling mediator in mammalian cells. Here we show that precise delivery of CO to isolated heart mitochondria using a water-soluble CO-releasing molecule (CORM-3) uncouples respiration. Addition of low-micromolar concentrations of CORM-3 (1-20 μM), but not an inactive compound that does not release CO, significantly increased mitochondrial oxygen consumption rate (State 2 respiration) in a concentration-dependent manner. In contrast, higher concentrations of CORM-3 (100 μM) suppressed ADP-dependent respiration through inhibition of cytochrome c oxidase. The uncoupling effect mediated by CORM-3 was inhibited in the presence of the CO scavenger myoglobin. Moreover, this effect was associated with a gradual decrease in membrane potential (ψ) over time and was partially reversed by malonate, an inhibitor of complex II activity. Similarly, inhibition of uncoupling proteins or blockade of adenine nucleotide transporter attenuated the effect of CORM-3 on both State 2 respiration and Δψ. Hydrogen peroxide (H₂O₂) produced by mitochondria respiring from complex I-linked substrates (pyruvate/malate) was increased by CORM-3. However, respiration initiated via complex II using succinate resulted in a fivefold increase in H₂O₂ production and this effect was significantly inhibited by CORM-3. These findings disclose a counterintuitive action of CORM-3 suggesting that CO at low levels acts as an important regulator of mitochondrial respiration.

Lidocaïne test for easier and less time consuming assessment of liver function in several hepatic injury models

PURPOSE

In this study, we developed an ex vivo functional assay to assess liver metabolic capacity adapted from the lidocaïne test in rats.

METHODS

Animals used were subjected to different models of liver injury: hypothermic ischemia (H/I, n = 8), ischemia-reperfusion (I/R, n = 8) and CCl4 induced liver cirrhosis (n = 11), and compared with sham operated rats (n = 5). Livers were then extracted and a fragment of whole tissue was incubated with lidocaïne for 15, 30, 60, 120, 240, 360, and 720 min at which both lidocaïne and its major metabolite monoethylglycinexylidide (MEGX) were measured by high performance liquid chromatography (HPLC). A histological study and biochemical assays (transaminase levels) were also performed to further evaluate and confirm our data.

RESULTS

Pharmacokinetic profile of lidocaïne metabolism in sham-operated animals revealed that the maximum concentration of MEGX is achieved at 120 min. Both lidocaïne metabolism and MEGX formation levels were significantly altered in all three models of hepatic injury. The extent of hepatic damage was confirmed by increased levels of transaminase levels and alteration of hepatocyte's structure with areas of necrosis.

CONCLUSION

Our method provides reliable and reproducible results using only a small portion of liver which allows for a fast and easy assessment of liver metabolic capacity. Moreover, our method presents an alternative to the in vivo technique and seems more feasible in a clinical setting.

[Heart rate reduction: beneficial effects in heart failure and post-infarcted myocardium]

Heart rate (HR) is an independent predicting factor of cardiovascular events in patients with advanced heart failure. Clinical trials conducted with beta-blockers have demonstrated that reduction of HR is a fundamental mechanism to explain the reduction of morbidity-mortality in such a disease. Trials conducted with ivabradine, the first selective inhibitor of the I(f) current in cardiac pacemaker cells, have also clearly confirmed that reduction of HR lead to powerful and sustained favourable effects in patients with cardiac failure and post-infarcted myocardial diseases. These effects are not only due to the reduction of the risk factors associated with myocardial ischemia but also to the reduction of cardiac and perivascular fibrosis associated with the remodelling process at the ventricular level. Although the mechanisms associated with reduction of HR following administration of beta-blockers and ivabradine are to a large extent similar, others like their effects on post-systolic contraction are totally opposed. So, new clinical trials are necessary to know whether it is possible to substitute these drugs or conversely to associate them for an optimal therapeutic strategy in patients with advanced heart failure and post-infarcted myocardium.