Sarcoplasmic reticulum: a key factor in cardiac contractility of sea bass Dicentrarchus labrax and common sole Solea solea during thermal acclimations

This study investigated the effects of acclimation temperature upon (i) contractility of ventricular strips (ii) calcium movements in ventricular cardiomyocytes during excitation-contraction coupling (ECC), and (iii) the role of the sarcoplasmic reticulum (SR) in myocardial responses, in two marine teleosts, the sea bass (Dicentrarchus labrax) and the common sole (Solea solea). Because of the different sensitivities of their metabolism to temperature variation, both species were exposed to different thermal ranges. Sea bass were acclimated to 10, 15, 20, and 25 °C, and common sole to 6, 12, 18, and 24 °C, for 1 month. Isometric tension developed by ventricular strips was recorded over a range of physiological stimulation frequencies, whereas the depolarization-induced calcium transients were recorded on isolated ventricular cells through hyperpotassic solution application (at 100 mM). The SR contribution was assessed by ryanodine (RYAN) perfusion on ventricular strips and by caffeine application (at 10 mM) on isolated ventricular cells. Rates of contraction and relaxation of ventricular strip, in both species, increased with increasing acclimation temperature. At a low range of stimulation frequency, ventricular strips of common sole developed a positive force-frequency relationship at high acclimation temperature. In both the species, SR Ca(2+)-cycling was dependent on fish species, acclimation temperature and pacing frequency. The SR contribution was more important to force development at low acclimation temperatures in sea bass but at high acclimation temperatures in common sole. The results also revealed that high acclimation temperature causes an increase in the maximum calcium response amplitude on ventricular cells in both the species. Although sea bass and common sole occupy similar environments and tolerate similar environmental temperatures, this study indicated that sea bass and common sole can acclimatize to new thermal conditions, adjusting their cellular process in a different manner.

Physicochemical properties and cellular toxicity of (poly)aminoalkoxysilanes-functionalized ZnO quantum dots

Luminescent ZnO nanocrystals were synthesized by basic hydrolysis of Zn(OAc)(2) in the presence of oleic acid and then functionalized with (poly)aminotrimethoxysilanes in the presence of tetramethylammonium hydroxide to render the QDs water-dispersible. The highest photoluminescence quantum yield (17%) was achieved using N(1)-(2-aminoethyl)-N(2)-[3-(trimethoxysilyl)propyl]-1,2-ethanediamine as surface ligand. Transmission electron microscopy and powder x-ray diffraction showed highly crystalline materials with a ZnO nanoparticle diameter of about 4 nm. The cytotoxicity of the different siloxane-capped ZnO QDs towards growing Escherichia coli bacterial cells was evaluated in MOPS-minimal medium. Although concentrations of 5 mM in QDs caused a complete growth arrest in E. coli, siloxane-capped ZnO QDs appeared weakly toxic at lower doses (0.5 or 1 mM). The concentration of bioavailable Zn (2+) ions leaked from ZnO QDs was evaluated using the biosensor bacteria Cupriavidus metallidurans AE1433. The results obtained clearly demonstrate that concentrations of bioavailable Zn(2+) are too low to explain the inhibitory effects of the ZnO QDs against bacteria cells at 1 mM and that the siloxane shell prevents ZnO QDs from dissolution contrary to uncapped ZnO nanoparticles. Because of their low cytotoxicity, good biocompatibility, low cost and large number of functional amine end groups, which makes them easy to tailor for end-user purposes, siloxane-capped ZnO QDs offer a high potential as fluorescent probes and as biosensors.

Influence of the amount of use on hand motor cortex representation: effects of immobilization and motor training

Converging evidence from animal and human studies has revealed that increased or decreased use of an extremity can lead to changes in cortical representation of the involved muscles. However, opposite experimental manipulations such as immobilization and motor training have sometimes been associated with similar cortical changes. Therefore, the behavioral relevance of these changes remains unclear. The purpose of this study was to observe the effect of the amount of use on hand muscle motor cortex representation by contrasting the effect of unspecific motor training and immobilization. Nine healthy volunteers were tested prior and after a 4-day exposure to two experimental conditions using a randomized cross-over design: a motor training condition (to play Guitar Hero 2h/day with the tested (nondominant) hand on the fret board) and an immobilization condition (to wear an immobilization splint 24h/day). Before and after each condition, motor cortex representation of the nondominant first dorsal interosseous (FDI) muscle was mapped using image-guided transcranial magnetic stimulation (TMS). At the behavioral level, results show that the training condition led to a 20% improvement in the trained task, while the immobilization condition resulted in a 36% decrease in the FDI maximal voluntary contraction. At the neurophysiological level, corticospinal excitability (e.g. Motor-evoked potential amplitude) was found to be decreased in response to immobilization, while no change was observed in response to motor training. No change was found for other TMS variables (motor thresholds or map location/volume/area) in either condition. In conclusion, our results indicate that a 4-day decrease, but not increase, in the amount of use of nondominant hand muscles is sufficient to induce a change in corticospinal excitability. The lack of a training effect might be explained by the use of an unspecific task (that is nevertheless representative of "real-life" training situations) and/or by insufficient duration/intensity to induce long-lasting changes.

Efficacy of a home-based intervention programme on the physical activity level and functional ability of older people using domestic services: a randomised study

OBJECTIVE

Our main objective was to assess whether a home-based program supervised by home helpers (HH) during their normal working hours can prevent excessive sedentariness (mainly maximum walking time and distance) and preserve functional status in elderly people at risk for frailty or disability and using domestic services.

DESIGN

A four-month, open label, randomised trial with two groups called "prevention" and "control".

SETTING

In the homes of study participants.

PARTICIPANTS

The participants were all over 78 years old, lived independently at home, and received the visits of HHs at least once a week.

INTERVENTION

The intervention combined a self-administered exercise program, with 10 g amino-acid supplementation under the supervision of HHs.

MEASUREMENTS

Main outcome measures included physical activity (the PASE questionnaire), functional tests, nutritional and autonomy scores, and compliance (50% or more was considered satisfactory). Non-parametric methods were used for comparisons between the two groups. A linear regression model was fitted to assess the effect of the intervention on the relative variation of outcomes, adjusted for unbalanced baseline co-variables.

RESULTS

One hundred and two persons (prevention n=53, control n=49) with a median age of 85 years were included. Their median Activities of Daily Living and Instrumental Activities of Daily Living (IADL) scores were 6 and 7 respectively. Twenty-three (44%) were good compliers for both interventions. The maximum walking time remained stable while decreasing by 25% in the control group (p=0.0015); and fewer participants had a worsened IADL score in the prevention group (p=0.05). The baseline IADL Score was significantly associated with good compliance to the prevention program (p=0.0011). In good compliers, maximum walking distance and maximum walking time increased by 29.15% (0.0 to 66.7) and 33.3% (-20.0 to 50.0) respectively.

CONCLUSION

This study confirms the feasibility of a prevention program supervised by HHs, and some benefit from the intervention and identifies predictors for better compliance. It will help in the design of prevention trials for elderly people at risk for frailty.

CDA deficiency as a possible culprit for life-threatening toxicities after cytarabine plus 6-mercaptopurine therapy: pharmacogenetic investigations

We describe here the case of a 7-year old girl with lymphoma who developed life-threatening toxicities upon cytarabine plus mercaptopurine. Surprisingly, initial investigations on canonical thiopurine methyltransferase genetic polymorphism proved to be negative. We focused next on deregulations affecting the CDA gene implicated in the liver disposition of cytarabine. This patient was homozygous for both the 79A>C and the -31delC polymorphisms on the CDA gene and promoter, two genotypes with reported opposite effects on CDA phenotype. To determine the CDA status of this patient, additional functional testing was performed and eventually demonstrated that this patient was a poor metabolizer. This case demonstrates that besides affecting thiopurine methyltransferase, dysregulations with CDA should be screened to anticipate toxicities with the cytarabine plus mercaptopurine combination.

Short-term reliability of transcranial magnetic stimulation motor maps in upper limb amputees

The aim of this study was to verify the short-term reliability of transcranial magnetic stimulation (TMS) parameters for a damaged stump muscle in upper-limb amputees (n=6). The motor threshold, response latency and map center of gravity in the mediolateral plane showed good reliability, whereas the map volume measure was less stable. The stability of most TMS measures across time supports the use of TMS in studying cortical plasticity in amputees.

5-FU-induced neurotoxicity in cancer patients with profound DPD deficiency syndrome: a report of two cases

PURPOSE

5-Fluorouracil (5-FU) is a mainstay for treating various solid tumours in adults, including digestive and head and neck cancers. 5-FU-related toxicities usually include haematological, digestive and cutaneous features. Additionally, 5-FU has been described as being potentially neurotoxic in patients, but these side effects are quite rare in clinical practice. Here, we report two cases of sudden and unpredictable drug-induced neurotoxicities that occurred in patients undergoing their first course of 5-FU-based chemotherapy.

PATIENTS AND METHODS

None of these patients had any previous neurological disorder history, and both were treated following standard regimen (LV-5-FU2 and TPF for patient 1 and 2, respectively). Neurotoxicity included drowsiness, acute confusion plus dysarthria for the first patient and seizure, confusion and signs of metabolic encephalopathy for the second one. In addition, typical 5-FU-related severe toxicities (e.g. neutropenia and mucosities) were observed. Both patients slowly recovered from these neurological toxicities under supportive treatment. It was assumed that overexposure to 5-FU could explain the severe toxicities encountered. To test this hypothesis, we retrospectively evaluated the dihydropyrimidine dehydrogenase (DPD) activity of these patients on a phenotypic basis.

RESULTS

Evaluation of the uracil-to-di-hydrouracil (U/UH2) ratio in plasma revealed a profound DPD deficiency syndrome in both patients.

CONCLUSION

These cases suggest that 5-FU standard dosage administration may lead to strong overexposure, responsible for the severe toxicities observed, including the neurological features. It implies that DPD deficiency can cause neurotoxicity in 5-FU-treated patients and advocates for the prospective screening of DPD deficiency before starting any 5-FU-containing chemotherapy so as to prevent such side effects in the future.

Intellectual disability and homelessness

BACKGROUND

The association between poverty and intellectual disability (ID) has been well documented. However, little is known about persons with ID who face circumstances of extreme poverty, such as homelessness. This paper describes the situation of persons with ID who were or are homeless in Montreal and are currently receiving services from a team dedicated to homeless persons.

AIMS

(1) To describe the characteristics, history and current situation of these persons; and (2) to report within-group differences as a function of gender and current residential status.

METHODS

The data were collected from files using an anonymous chart summary. Descriptive statistics on the whole sample (n = 68) and inferential statistics on cross-tabulations by gender and residential status were performed.

RESULTS

Persons with ID exhibited several related problems. Some of these persons, primarily women, experienced relatively short periods of homelessness and their situations stabilised once they were identified and followed up. Other persons with ID experienced chronic homelessness that appeared to parallel the number and severity of their other problems. When compared with a previous epidemiological study of the homeless in Montreal, the population of homeless persons with ID differed from the overall homeless population in a number of respects.

CONCLUSION

The results suggest prevention and intervention targets. The need for epidemiological research appears particularly clear in light of the fact that below-average intellectual functioning has been identified as a risk factor for homelessness and a predisposing factor for vulnerability among street people.

Routine dihydropyrimidine dehydrogenase testing for anticipating 5-fluorouracil-related severe toxicities: hype or hope?

5-Fluorouracil (5-FU) is a mainstay for treating colorectal cancer, alone or more frequently as part of combination therapies. However, its efficacy/toxicity balance is often limited by the occurrence of severe toxicities, showing in about 15%-20% of patients. Several clinical reports have shown the deleterious effect of dihydropyrimidine dehydrogenase (DPD) genetic polymorphism, a condition that reduces the liver detoxification step of standard dosages of 5-FU, in patients undergoing fluoropyrimidine-based therapy. Admittedly, DPD deficiency accounts for 50%-75% of the severe and sometimes life-threatening toxicities associated with 5-FU (or oral 5-FU). However, technical consensus on the best way to identify patients with DPD deficiency before administrating 5-FU is far from being achieved. Consequently, no regulatory step has been undertaken yet to recommend DPD testing as part of routine clinical practice for securing the administration of 5-FU. This review covers the limits and achievements of the various strategies proposed so far for determining DPD status in patients scheduled for 5-FU therapy.

Integrating pharmacogenetics into gemcitabine dosing--time for a change?

Increasing the efficacy of anticancer agents and avoiding toxic effects is a critical issue in clinical oncology. Identifying biomarkers that predict clinical outcome would ensure improved patient care. Gemcitabine is widely used to treat various solid tumors as a single agent or in combination with other drugs. The therapeutic index of gemcitabine is narrow, and abnormal pharmacokinetics leading to changes in plasma exposure is a major cause of adverse effects. A number of biomarkers have been proposed to predict efficacy of gemcitabine, focusing on molecular determinants of response identified at the tumor level. Genetic and functional deregulations that affect the disposition of a drug could be the reason for life-threatening adverse effects or treatment failure. In particular, deregulation of cytidine deaminase, the enzyme responsible for detoxification of most nucleotide analogs, should be examined. Identifying and validating biomarkers for pharmacogenetic testing before administration of gemcitabine is a step towards personalized medicine.

Influence of the C/Sn Ratio on the Synthesis and Lithium Electrochemical Insertion of Tin-Supported Graphite Materials Used as Anodes for Li-Ion Batteries

Novel composites consisting of tin particles associated to graphite were prepared by chemical reduction of tin(+2) chloride byt-BuONa-activated sodium hydride in the presence of graphite. The samples obtained using various C/Sn ratios were investigated by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and elemental analyses. The largest tin particles associated to graphite layers were observed for the material with a C/Sn ratio of 16. For the materials with C/Sn ratios of 42 and 24, SEM and TEM experiments demonstrated that Sn aggregates of ca. 250 nm length and composed of Sn particles with an average diameter of ca. 50 nm were homogeneously distributed at the surface of graphite. Electrodes prepared from theC/Sn=42material exhibit a high reversible capacity of over 470 mAhg−1up to twenty cycles with stable cyclic performances.

Erlotinib in combination with capecitabine (5'dFUR) in resistant pancreatic cancer cell lines

The combination of capecitabine and the tyrosine kinase inhibitor erlotinib has recently been tested in patients with gemcitabine-refractory pancreatic tumors, with limited success. To understand this lack of efficacy, we studied the molecular effects of these agents in Capan-1 and Capan-2 human pancreatic resistant cancer cells. Erlotinib up-regulated thymidine phosphorylase (+50%) and downregulated dihydropyrimidine dehydrogenase (+55%) in a cell-dependent manner, thus suggesting that the combination should result in synergism. However, only mild additivity was achieved at best when combining both drugs, and several sequences tested even led to strong antagonism. Further experiments were performed to understand this lack of efficacy. We found that the fluoropyrimidine down-regulated EGFR expression by 30%, an unexpected finding resulting in a possible reduction in efficacy when cells were subsequently exposed to erlotinib. We also observed marked drug-induced over-expression of both cytosolic and extracellular vascular endothelial growth factor (VEGF) secretion, thus possibly triggering proliferation. These preliminary findings strongly suggest that these observations could be new mechanisms in the development of acquired drug resistance in pancreatic cancer cells.

Peri-insular hemispherotomy in children: a single institution experience

The objective of this paper is to evaluate our experience in performing peri-insular hemispherotomy in refractory epileptic children. First, we address the history of hemispheric surgeries for epilepsy and then we compare our results to the medical literature in term of seizure control and complications. Between 1993 and 2007, 14 children who suffered from refractory hemispheric epilepsy underwent a peri-insular hemispherotomy. All children's charts were reviewed in a retrospective manner. Age at onset of epilepsy, imaging studies, cause of refractory epilepsy, electroencephalography findings, type of epileptic seizure, number of antiepileptic drugs (AED), preoperative neuropsychological evaluation and surgical outcome with regard to the children's seizure activity were analyzed. Nine boys and 5 girls were enrolled in this study. The mean age at onset of epilepsy was 16 months (range birth-5 years). All the children presented complex partiel seizures. Seizure frequency varied from 5 to 100 a day. The average delay prior to the hemispherotomy was 83 months (range 12-226 months). Mean age at the time of the surgery was 8.4 years (range 1.7-18 years). We performed 9 peri-insular hemispherotomies on the right side and 5 on the left. There were no reported surgical complications in this series. 10 children are seizure free (72%). Peri-insular hemispherotomy must be considered as a safe and very efficient therapeutic approach for children suffering from hemispheric refractory epilepsy. Peri-insular hemispherotomies are procedures where pathology and surgical technique interact narrowly. Acquired pathologies had better results than developmental ones.

Cytidine deaminase residual activity in serum is a predictive marker of early severe toxicities in adults after gemcitabine-based chemotherapies

PURPOSE Anticipating toxicities with gemcitabine is an ongoing story, and deregulation in cytidine deaminase (CDA) could be associated with increased risk of developing early severe toxicities on drug exposure. PATIENTS AND METHODS A simple test to evaluate CDA phenotypic status was first validated in an animal model investigating relationships between CDA activity and gemcitabine-related toxicities. Next, relevance of this test as a marker for toxicities was retrospectively tested in a first subset of 64 adult patients treated with gemcitabine alone, then it was tested in a larger group of 130 patients who received gemcitabine either alone or combined with other drugs and in 20 children. Additionally, search for the 435 T>C, 208 G>A and 79 A>C mutations on the CDA gene was performed. Results In mice, CDA deficiency impacted on gemcitabine pharmacokinetics and had subsequent lethal toxicities. In human, 12% of adult patients experienced early severe toxicities after gemcitabine administration. A significant difference in CDA activities was observed between patients with and without toxicities (1.2 +/- 0.8 U/mg v 4 +/- 2.6 U/mg; P < .01). Conversely, no genotype-to-phenotype relationships were found. Of note, the patients who displayed particularly reduced CDA activity all experienced strong toxicities. Gemcitabine was well tolerated in children, and no CDA deficiency was evidenced. CONCLUSION Our data suggest that CDA functional testing could be a simple and easy marker to discriminate adult patients at risk of developing severe toxicities with gemcitabine. Particularly, this study demonstrates that CDA deficiency, found in 7% of adult patients, is associated with a maximum risk of developing early severe toxicities with gemcitabine.

Pharmacoeconomic study in head and neck cancer patients: Impact of prospective DPD deficiency screening with 5-fluorouracil (5-FU) dose tailoring on toxicities-related costs

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Background: Dihydropyrimidine dehydrogenase (DPD) plays a pivotal role in the detoxification of 5-FU. We studied the impact of screening DPD impairment in head and neck cancer (HNC) patients, both on reduction of drug-related toxicities and as a pharmacoeconomic endpoint. Methods: A total of 148 consecutive patients with HNC treated with 5-FU+platinum were monitored. Seventy-four patients (Arm A - before 2006) were treated with standard dosage, whereas 74 other patients (Arm B - after 2006) had their DPD status phenotypically evaluated prior to receiving 5-FU, with subsequent dose reduction if DPD deficiency were suspected. Severe toxicities and response were compared. Additionally, direct and indirect costs required to manage the treatment-related toxicities and to establish DPD status were calculated. Results: Sepsis was observed in 16.2% of patients treated with standard dosage. In Arm B, DPD deficiency was suspected in 35% of the patients and 5-FU dosage was subsequently reduced. Consequently, only 1.8% of them experienced sepsis. Of note, response rates were comparable between Arm A and B (62 vs 61%, p>0.05), thus demonstrating that 5-FU dose tailoring did not negatively impact on treatment efficacy, while reducing the occurrence of severe toxicities. Managing toxicities required an average 23-days of extra-hospitalization (4–96 days), including an average 1.6-day stay in ICU. No patients from Arm B had to stay in ICU. Drugs required for managing toxicities cost an average of $339 per patient (Arm A) and was reduced down to $38 per patient (Arm B). Similarly, mean extra-hospitalization cost was $5,940/patient in Arm A and $245/patient in Arm B. Testing DPD cost $49/patient in Arm B. Conclusions: Developing an adaptative dosing strategy based upon DPD status evaluation led to a dramatic reduction of the incidence of 5-FU-related severe toxicities, while maintaining optimal efficacy. Subsequently, extra-cost (medication + hospitalization costs) required to manage the toxicities fell down from $6,279 to $294/patient. Overall, this study advocates that systematic screening for DPD deficiency could be cost-efficient in the setting of 5-FU-based chemotherapies, with a reduction of 95% of the extra-costs.

No significant financial relationships to disclose.

Comparison of primary angioplasty and pre-hospital fibrinolysis in acute myocardial infarction (CAPTIM) trial: a 5-year follow-up

AIMS

The CAPTIM (Comparison of primary Angioplasty and Pre-hospital fibrinolysis In acute Myocardial infarction) study found no evidence that a strategy of primary angioplasty was superior in terms of 30-day outcomes to a strategy of pre-hospital fibrinolysis with transfer to an interventional facility in patients managed early at the acute phase of an acute myocardial infarction. The present analysis was designed to compare both strategies at 5 years.

METHODS AND RESULTS

The CAPTIM study included 840 patients managed in a pre-hospital setting within 6 h of an acute ST-segment elevation myocardial infarction. Patients were randomized to either a primary angioplasty (n = 421) or a pre-hospital fibrinolysis (rt-PA) with immediate transfer to a centre with interventional facilities (n = 419). Long-term follow-up was obtained in blinded fashion from 795 patients (94.6%). Using an intent-to-treat analysis, all-cause mortality at 5 years was 9.7% in the pre-hospital fibrinolysis group when compared with 12.6% in the primary angioplasty group [HR 0.75 (95% CI, 0.50-1.14); P = 0.18]. For patients included within 2 h, 5 year mortality was 5.8% in the pre-hospital fibrinolysis group when compared with 11.1% in the primary angioplasty group [HR 0.50 (95% CI, 0.25-0.97); P = 0.04], whereas it was, respectively, 14.5 and 14.4% in patients included after 2 h [HR 1.02, (95% CI 0.59-1.75), P = 0.92].

CONCLUSION

The 5-year follow-up is consistent with the 30-day outcomes of the trial, showing similar mortality for primary percutaneous coronary intervention and a policy of pre-hospital lysis followed by transfer to an interventional center. In addition, for patients treated within 2 h of symptom onset, 5-year mortality was lower with pre-hospital lysis.

Vagus nerve stimulation in pediatric epileptic syndromes

Vagal nerve stimulation (VNS) has shown promising results in various cohorts of non-surgical refractory epilepsy in adults and children. However studies report a significant delay between implantation and clinical response. We describe a cohort of 28 children and adolescents prospectively followed, classified by epileptic syndromes and treated with VNS using a 6-week rapid ramping protocol between January 2000 and March 2005. Our cohort showed favorable outcome within 6 months which was sustained at 24 months: 68% (19/28) showing >or=50% reduction in seizure frequency, including 14% (4/28) who became seizure-free. VNS was particularly efficacious in children with cryptogenic generalized and partial epilepsies. Although adverse events occurred in 68% (19/28) of patients, most were transient. In conclusion, rapid ramping is associated with an early and lasting response in most children but with a slightly higher side-effect rate.

[Fetal assessment of the labor admission in low risk pregnancies]

The assessment of fetal well-being at the beginning of labor must lead to an appropriate monitoring, adapted to the present risks. Even if some medical events are unforeseeable, three ways of reflexions get clear: abnormal maternofetal signs at the admission indicate the need for an increased monitoring (NP5); the reading of the medical file could reveal a high-risk pregnancy; at least, the realization of electronic fetal heart rate monitoring for any woman at the beginning of the labor is recommended: in case of normality, it remains a good criterion of a fetal good health. In this context of admission, there is no evidence supporting that other techniques (amnioscopy, acoustic test, echography, Doppler, etc.) could be beneficial in low-risk women and be recommended (NP5). Research is to be continued in this field.

Toxic death case in a patient undergoing gemcitabine-based chemotherapy in relation with cytidine deaminase downregulation

Gemcitabine is an antimetabolite drug used in the treatment of various solid tumours, including lung, pancreatic or gynaecological cancers. Innovative combinational strategies (e.g. gemcitabine+capecitabine or gemcitabine+oxaliplatin) make gemcitabine an extensively prescribed drug now. Gemcitabine is characterized by a narrow therapeutic index, and its liver elimination depends upon a key enzymatic step, driven by cytidine deaminase (CDA). CDA is prone to gene polymorphism, including the 208A>G mutation, which can result in marked enzymatic deficiency with subsequent impact on drug exposure levels and related toxicities. We have developed a simple and inexpensive method to determine phenotypically CDA status in cancer patients, as an attempt to detect those at risk upon gemcitabine intake. Conjointly to genotypic investigations, this method was used to phenotype, in a retrospective setting, a female patient displaying extremely severe, and eventually lethal, toxicities after administration of a standard gemcitabine/carboplatin protocol. Phenotypic investigation showed a marked CDA deficiency (-75%) in this patient when compared with a reference, nontoxic population. Genetic studies undertaken next to screen mutations, possibly at the origin of this deficiency, showed heterozygosity for the 79A>C single-point mutation, whereas surprisingly the canonical CDA 208A>G polymorphism was not found. Taken together, this case report demonstrates, for the first time, that CDA downregulation can lead to toxic-death in patients exposed to gemcitabine. Besides, we showed here that our cost-effective and simple phenotypic approach should enable, in the future, the detection of deficient patients at risk upon gemcitabine administration.

Profiles and correlates of aggressive behaviour among adults with intellectual disabilities

BACKGROUND

Despite the heterogeneity in aggressive behaviours observed among individuals with intellectual disabilities (ID), little attention has been paid to the identification of typologies of aggression among individuals with mild or moderate ID and their associated factors.

OBJECTIVE

The goal of the present study was to identify profiles of aggressive behaviour and their psychosocial correlates.

METHOD

In this cross-sectional study of 296 adults with mild or moderate ID, information was gathered through interviews with the ID participants, their case manager and a significant other. Client files were also reviewed.

RESULTS

Multiple correspondence analysis followed by hierarchical cluster analysis generated six distinct profiles of aggressive behaviour in this sample. The 'violent' group clearly stood out as lacking social and vocational involvement, having more severe mental health problems, high levels of impulsivity and antisocial tendencies compared with all other groups.

DISCUSSION

The identification of distinct profiles of aggressive behaviour offers new possibilities for studying risk factors and eventually targeting specific risk prevention strategies.

In vitro and in vivo reversal of resistance to 5-fluorouracil in colorectal cancer cells with a novel stealth double-liposomal formulation

Drug resistance is a major cause of treatment failure in cancer chemotherapy, including that with the extensively prescribed antimetabolite, 5-fluorouracil (5-FU). In this study, we tried to reverse 5-FU resistance by using a double-punch strategy: combining 5-FU with a biochemical modulator to improve its tumoural activation and encapsulating both these agents in one same stealth liposome. Experiments carried out in the highly resistant, canonical SW620 human colorectal model showed a up to 80% sensitisation to 5-FU when these cells were treated with our liposomal formulation. Results with this formulation demonstrated 30% higher tumoural drug uptake, better activation with increased active metabolites including critical-5-fluoro-2-deoxyuridine-5-monophosphate, superior inhibition (98%) of tumour thymidylate synthase, and subsequently, higher induction of both early and late apoptosis. Drug monitoring showed that higher and sustained exposure was achieved in rats treated with liposomal formulation. When examined in a xenograft animal model, our dual-agent liposomal formulation caused a 74% reduction in tumour size with a mean doubling in survival time, whereas standard 5-FU failed to exhibit significant antiproliferative activity as well as to increase the lifespan of tumour-bearing mice. Taken collectively, our data suggest that resistance to 5-FU can be overcome through a better control of its intratumoural activation and the use of an encapsulated formulation.

Prospective phenotypic screening for DPD deficiency in patients upon fluoropyrimidines administration: Impact on the reduction of drug-induced toxicities

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Background: DPD deficiency is a pharmacogenetic syndrome associated with severe toxicities upon 5-FU/capecitabine intake. To detect patients at risk upon fluoropyrimidines administration we developed a simple, rapid and inexpensive phenotypic method for DPD status evaluation. Here, clinical relevance of DPD deficiency a priori determination was studied. Methods: This method was used prospectively in 50 head and neck cancers patients (60±7 years, 37M/13F). Screening for DPD deficiency was performed prior to the beginning of the platinum + 5-FU (± radiation therapy) administration. DPD status was evaluated by HPLC monitoring U/UH2 ratio levels in plasma as a surrogate marker. Only 5-FU doses were adjusted according to the level of detected impairment (mild deficiency: -20%, severe: - 50%, total: no 5-FU). Drug-induced toxicities and subsequent impact on treatment schedule were carefully monitored next for comparison with a retrospective subset of 50 patients (mean age: 58±9 years, 40M/10F), treated with standard dosage of the same chemotherapy or radio- chemotherapy schedule. Results: DPD determination permitted the detection of 11 patients with DPD impairment out of 50 (22%). These 11 patients had their 5-FU doses customized and, consequently, neither severe toxicity nor delays in the administration radiation therapy or chemotherapy were reported in this group. Conversely, 7 out of 50 (14%) patients administered with standard dosage of 5-FU displayed severe toxicities (>grade-3, WHO grading), with subsequent postponement of the following courses. One patient (2%) did not recover from his toxicities. Of these 8 patients, retrospective determination of DPD status suggested impaired function in 7 of them (87%), including the toxic- death one. Conclusions: Although non randomized, this study suggests that prospective use of DPD status has an immediate clinical benefit by, reducing the drug-induced toxicities incidence in patients treated with 5-FU, and allowing an optimal administration of several courses in a row. Our preliminary results advocate systematic DPD status screening in patients eligible for treatment with fluoropyrimidine drugs. Survival and response study still on going.

No significant financial relationships to disclose.

Vision without Proprioception Modulates Cortico-spinal Excitability during Hand Motor Imagery

Several studies have shown a cortico-spinal facilitation during motor imagery. This facilitation effect is weaker when the actual hand posture is incompatible with the imagined movement. To determine whether the source of this interference effect arises from online proprioceptive information, we examined transcranial magnetic stimulation (TMS)-induced motor-evoked potentials during motor imagery in the deafferented subject G.L. The patient and 7 control subjects were asked to close their eyes and imagine joining the tips of the thumb and the little finger while maintaining a hand posture compatible or incompatible with the imagined movement. Contrary to control subjects' performance, G.L.'s results show that the facilitation observed during motor imagery was independent of the hand posture. To examine how vision of the hand interacts with the imagery process, G.L. and control subjects performed the same task with the eyes open. Like control subjects, when G.L. looked at her hand, a greater facilitation was observed when her hand posture was compatible with the imagined movement than when it was incompatible. These results suggest that in the absence of proprioception, vision may facilitate or inhibit motor representations and support the idea that limb position in the brain is organized around multisensory representations.

Auditory processing in a patient with a unilateral lesion of the inferior colliculus

The role of the inferior colliculus (IC) in human auditory processing is still poorly understood. We report here the results obtained with a 12-year-old boy (FX) who suffered a very circumscribed lesion of the right IC without additional neurological damage. The child underwent an extensive battery of psychophysical hearing tests. Results revealed normal peripheral auditory functioning, bilaterally. Furthermore, masking-level differences and frequency-pattern recognition were normal for each ear. When the right ear was stimulated, behavioural tests assessing central auditory processing yielded normal results. However, when the left ear was stimulated, speech recognition in the presence of a competing ipsilateral signal and duration-pattern recognition were impaired. Similarly, performance on two dichotic speech recognition tests was poor when the target stimulus was presented in the left and the competing signal in the right ear. Finally, sound-source localization in space was deficient for speakers located on the side contralateral to the lesion. The pattern of results suggests that auditory functions such as recognition of low-redundancy speech presented monaurally, recognition of tone duration patterns, binaural separation and integration, as well as sound-source localization in space, depend on the integrity of the bilateral auditory pathways at the IC level.

Profiling dihydropyrimidine dehydrogenase deficiency in patients with cancer undergoing 5-fluorouracil/capecitabine therapy

Fluoropyrimidine drugs such as 5-fluorouracil (5-FU) and capecitabine are a mainstay in the treatment of numerous solid tumors, including colorectal cancers, alone or as part of combination therapies. Cytotoxic drugs such as 5-FU and oral capecitabine display narrow therapeutic indexes combined with high interpatient pharmacokinetic variability. As a result, severe toxicities often limit or delay the administration of successive, optimal chemotherapeutic courses, leading to unfavorable clinical outcome in patients with cancer. Catabolism and deactivation of fluoropyrimidine drugs depend on a single and exclusive enzymatic step driven by dihydropyrimidine dehydrogenase (DPD). Dihydropyrimidine dehydrogenase is prone to marked circadian rhythms, drug-drug interactions, and genetic polymorphisms; influence of its erratic activity on 5-FU pharmacokinetics and toxicity profile has been extensively investigated, and it is now well known that DPD deficiency leads to severe toxicities with 5-FU or possibly capecitabine exposure. With the ever-increasing number of patients with cancer likely to be treated with fluoropyrimidines, predicting and preventing the occurrence of such toxicities is now a major issue in clinical oncology. Early determination of DPD status in patients with cancer would allow identification of those at risk and help in subsequent dose adjustment or selection of other treatment modalities. Numerous methods, either genotypic or phenotypic, have been proposed to achieve this goal. This review covers a wide range of techniques available to establish DPD status in patients with cancer.

Genetic and biochemical modulation of 5-fluorouracil through the overexpression of thymidine kinase: an in-vitro study

The pro-drug 5-fluorouracil (5-FU) exerts its anti-proliferative action after conversion into cytotoxic metabolites. We previously demonstrated that the anti-cancer action of 5-FU could be enhanced by boosting thymidine phosphorylase (TP) activity in cancer cells, the first step of the DNA pathway, that yields the critical anti-thymidylate synthase (TS) fluorodeoxyuridine monophosphate (FdUMP) metabolite. In the present study, we further studied to what extent 5-FU activity could be optimized by overexpressing cancer cell thymidine kinase (TK), the second step of the DNA pathway, for which controversial data have been published so far. Additionally, screening of biochemical modulators likely to contribute to 5-FU activation was also carried out. TK-overexpressing colorectal cells were obtained after designing vectors harboring viral and human cDNA, and performing stable transfection in the human HT29 cell line. Anti-proliferative assays were subsequently performed so as to evaluate change in cell sensitivity to 5-FU, and metabolism monitoring was carried out to follow drug activation and FdUMP formation after cellular uptake. Finally, TS inhibition was assessed as a pharmacological endpoint. Results showed that overexpression of TK led to a marked desensitization of our model. A negative correlation (r = 0.87) was found between the level of TK activity and 5-FU anti-proliferative action - the higher the activity, the lower the sensitivity. Of the various drugs screened as putative modulators, only those involved in TP activity proved to enhance 5-FU efficacy via optimized FdUMP formation. Conversely, genetically increasing TK activity did not modify 5-FU activation pathway nor subsequent TS inhibition in our model. Therefore, our results indicate that TK is not a limiting step in the production of anti-TS FdUMP and that tumor cells overexpressing TK are likely to resist 5-FU-based chemotherapies.

A rapid and inexpensive method for anticipating severe toxicity to fluorouracil and fluorouracil-based chemotherapy

Dihydropyrimidine dehydrogenase (DPD) deficiency leads to dramatic overexposure to fluorouracil (5-FU), resulting in a potentially lethal outcome in patients treated with standard doses. The aim of this study was to validate, in a routine clinical setting, a simple and rapid method to determine the DPD status in a subset of cancer patients, all presenting with life-threatening toxicities following 5-FU or capecitabine intake. In this study, 80 out of 615 patients (13%) suffered severe toxicities, including 5 lethal ones (0.8%), during or after chemotherapy with a fluoropyrimidine drug. Patients with severe toxicities were treated with 5-FU (76 patients) or capecitabine-containing protocols (4 patients). Simplified uracil to di-hydrouracil (U/UH2) ratio determination in plasma was retrospectively performed in these 80 patients, as a surrogate marker of DPD activity. When possible, 5-FU Css determination was performed, and screenings for the canonical IVS14+1G>A mutation were systematically carried out. Comparison of the U/UH2 ratios with a reference, non-toxic population, showed abnormal values suggesting impaired DPD activity in 57 out of the 80 toxic patients (71%) included in this study, and in 4 out of 5 patients (80%) with a fatal outcome. Similarly, drug exposures up to 15 times higher than the range observed in the non-toxic population were also observed. Importantly, no IVS14+1G>A mutation was found in these patients, including those displaying the most severe or lethal toxicities. These data warrant systematic detection of DPD-deficient patients prior to fluoropyrimidine administration, including when oral capecitabine (Xeloda) is scheduled. Finally, the simplified methodology presented here proved to be a low cost and rapid way to identify routinely patients at risk of toxicity with 5-FU or capecitabine.

Therapeutic drug monitoring for dose individualization of Cisplatin in testicular cancer patients based upon total platinum measurement in plasma

Cisplatin (CDDP) is an anticancer agent widely used in testicular cancer, for which pharmacokinetic (PK)/pharmacodynamic relationships have usually been based upon measurement of its unbound fraction in plasma. Because it has been shown that free CDDP clearance can be related to patient's body surface area (BSA), dosage is mostly adjusted a priori using only this single parameter, with mixed results for accurately predicting CDDP exposure and reducing toxicities. In contrast, the authors present here an original, 5-day continuous infusion schedule, coupled to a daily Bayesian adaptive dosing with feedback strategy, based upon the rapid assay of total, rather than free, CDDP in plasma. Nineteen patients (66 therapeutic courses) were treated with platinum-based combinational therapy. Plasma samples were analyzed to allow real-time Bayesian estimation of individual PK parameters with subsequent prospective dose adjustment in order to reach a target Cmax (Cend) of 1.95 mg/L of total platinum. Performance of the Bayesian dosing method was evaluated by comparing target Cmax with achieved Cmax. The mean+/-SD Cmax achieved was 1.93+/-0.16 mg/L. No statistically significant difference was observed between experimental and target values (P>0.05, t test), and Cend achievement was done with an overall 6.6% precision, a performance to be compared with the initial 54% interpatient variability observed in CDDP clearance. A nonlinear mixed effect model population PK analysis was subsequently performed to identify retrospectively the covariates associated with PK parameters of total CDDP. It showed a good correlation (r=0.84, P=0.004) between total platinum clearance and therapeutic course number. A weaker correlation (r=0.59) was found between BSA and total CDDP clearance and, importantly, no additional relationship was established with BSA when successive therapeutic courses, and not only the first one, were considered. This highlights the critical importance of total drug accumulation on CDDP pharmacokinetics when several infusions are to be administered in a row and, therefore, the need for real-time dose individualization that takes into account the course number, rather than BSA. Finally, doses of CDDP administered during each course were significantly higher (+20%, P<0.01) than the ones classically normalized with BSA, thus leading to an overall greater drug exposure in the patients. It is noteworthy that despite these markedly higher doses, little severe toxicity was reported, and all of the patients presented in this study were still alive and disease free after a follow-up of up to 15 years.

Prevalence and types of aggressive behaviour among adults with intellectual disabilities

BACKGROUND

Aggressive behaviours represent major obstacles to the integration into society of individuals with intellectual disability (ID) and pose significant management issues for carers.

METHODS

The present study assessed the prevalence and severity of five types of aggressive behaviours in 3165 adult men and women with ID receiving services from three rehabilitation agencies in Québec by surveying their carers using the Modified Overt Aggressive Scale.

RESULTS

The 12-month prevalence of aggressive behaviour was 51.8%: 24% property damage, 37.6% verbal, 24.4% self-oriented and 24.4% physical aggression, and 9.8% sexually aggressive behaviour, most of which being mild in severity. Only 4.9% of individuals displayed aggressive behaviour leading to injury of the victim. Few gender differences were observed.

CONCLUSIONS

The capacity to document and assess the types as well as the severity of aggressive behaviour is thus critical, not only to better understand the correlates of various types of behaviours but also to orient intervention programmes whether they be prevention, assessment, monitoring or management of aggressive behaviour.