Correlated optical and electrical analyses of inhomogeneous core/shell InGaN/GaN nanowire light emitting diodes

The performance of core-shell InGaN/GaN nanowire (NW) light emitting diodes (LEDs) can be limited by wire-to-wire electrical inhomogeneities. Here we investigate an array of core-shell InGaN/GaN NWs which are morphologically identical, but present electrical dissimilarities in order to understand how the nanoscale phenomena observed in individual NWs affect the working performance of the whole array. The LED shows a low number of NWs (∼20%) producing electroluminescence under operating conditions. This is related to a presence of a potential barrier at the interface between the NW core and the radially grown n-doped layer, which differently affects the electrical properties of the NWs although they are morphologically identical. The impact of the potential barrier on the performance of the NW array is investigated by correlating multi-scanning techniques, namely electron beam induced current microscopy, electroluminescence mapping and cathodoluminescence analysis. It is found that the main cause of inhomogeneity in the array is related to a non-optimized charge injection into the active region, which can be overcome by changing the contact architecture so that the electrons become injected directly in the n-doped underlayer. The LED with so-called 'front-n-contacting' is developed leading to an increase of the yield of emitting NWs from 20% to 65%.

[Do initial experience with an enhanced recovery program after surgery (ERAS) improve postoperative outcomes after cystectomy?]

OBJECTIVE

To estimate the feasibility and the impact of an ERAS program after radical cystectomy for bladder cancer.

MATERIALS AND METHODS

This was a retrospective study comparing a historical pre ERAS group, including all the patients undergoing cystectomy for bladder cancer from January 2013 to December 2015 with a classic procedure, and an interventional ERAS group after introducing an enhanced recovery protocol before, during and after surgery, from February 2016. The principal outcome was the postoperative length of stay. Secondary outcomes mesures were impact on perioperative complication rate (Clavien classification≥3B), readmission rate, reanimation length of stay, ileus rate and adherence to the ERAS protocol.

RESULTS

There were no differences between the 2 groups as far as demographics characteristics are concerned. In total, 97 patients were included, 56 in the control group, and 41 in the ERAS group. The adherence to the protocol was about 65.8%. The ERAS group had statistically significantly shorter median length of stay (D19 versus D14; P: 0.021). The major complications rate (Clavien≥3B) were about 23.2% for the control group and 12.1% for the ERAS group (P: NS). The reinsertion of nasogastric tube were higher in the control group (39.3% vs 21.9%; P: NS) and the readmission rate was about 7.1% in the control group versus 14.6% in the ERAS group (P: NS).

CONCLUSION

In conclusion, introduction and application of an enhanced recovery protocol (ERAS) after cystectomy for bladder cancer allowed for better management of postoperative outcomes. It is clearly feasible in cystectomy, and improve significantly the median postoperative length of stay. Moreover, it may be effective in terms of faster return of bowel function and reduction of majors complications.

LEVEL OF EVIDENCE

4.

Investigation of Photovoltaic Properties of Single Core-Shell GaN/InGaN Wires

We report the investigation of the photovoltaic properties of core-shell GaN/InGaN wires. The radial structure is grown on m-plane {11̅00} facets of self-assembled c̅-axis GaN wires elaborated by metal-organic vapor phase epitaxy (MOVPE) on sapphire substrates. The conversion efficiency of wires with radial shell composed of thick In0.1Ga0.9N layers and of 30× In0.18Ga0.82N/GaN quantum wells are compared. We also investigate the impact of the contact nature and layout on the carrier collection and photovoltaic performances. The contact optimization results in an improved conversion efficiency of 0.33% and a fill factor of 83% under 1 sun (AM1.5G) on single wires with a quantum well-based active region. Photocurrent spectroscopy demonstrates that the response ascribed to the absorption of InGaN/GaN quantum wells appears at wavelengths shorter than 440 nm.

Core-shell InGaN/GaN nanowire light emitting diodes analyzed by electron beam induced current microscopy and cathodoluminescence mapping

We report on the electron beam induced current (EBIC) microscopy and cathodoluminescence (CL) characterization correlated with compositional analysis of light emitting diodes based on core/shell InGaN/GaN nanowire arrays. The EBIC mapping of cleaved fully operational devices allows to probe the electrical properties of the active region with a nanoscale resolution. In particular, the electrical activity of the p-n junction on the m-planes and on the semi-polar planes of individual nanowires is assessed in top view and cross-sectional geometries. The EBIC maps combined with CL characterization demonstrate the impact of the compositional gradients along the wire axis on the electrical and optical signals: the reduction of the EBIC signal toward the nanowire top is accompanied by an increase of the CL intensity. This effect is interpreted as a consequence of the In and Al gradients in the quantum well and in the electron blocking layer, which influence the carrier extraction efficiency. The interface between the nanowire core and the radially grown layer is shown to produce in some cases a transitory EBIC signal. This observation is explained by the presence of charged traps at this interface, which can be saturated by electron irradiation.

Daclizumab Versus Rabbit Antithymocyte Globulin in High-Risk Renal Transplants: Five-Year Follow-up of a Randomized Study

We previously reported a randomized controlled trial in which 227 de novo deceased-donor kidney transplant recipients were randomized to rabbit antithymocyte (rATG, Thymoglobulin) or daclizumab if they were considered to be at high immunological risk, defined as high panel reactive antibodies (PRA), loss of a first kidney graft through rejection within 2 years of transplantation, or third or fourth transplantation. Patients treated with rATG had lower incidences of biopsy-proven acute rejection (BPAR) and steroid-resistant rejection at 1 year. Patients were followed to 5 years posttransplant in an observational study; findings are described here. Treatment with rATG was associated with a lower rate of BPAR at 5 years (14.2% vs. 26.0% with daclizumab; p = 0.035). Only one rATG-treated patient (0.9%) and one daclizumab-treated patient (1.0%) developed BPAR after 1 year. Five-year graft and patient survival rates, and renal function, were similar between the two groups. Overall graft survival at 5 years was significantly higher in patients without BPAR (81.0% vs. 54.8%; p < 0.001). In conclusion, rATG is superior to daclizumab for the prevention of BPAR among high-immunological-risk renal transplant recipients. Overall graft survival at 5 years was approximately 70% with either induction therapy, which compares favorably to low-risk cohorts.

Studies of circulating microparticle release in peripheral blood after pancreatic islet transplantation

The loss of graft function after intraportal islet transplantation is likely multifactorial involving allogeneic rejection, recurrent autoimmunity, graft exhaustion due to a marginally implanted islet mass, immunosuppressant toxicity, and impaired β-cell regeneration. Because early markers of the loss of β-cell mass or function are lacking, monitoring of islet function remains a challenging issue. We have reported herein monitoring of membrane procoagulant microparticles (MPs) as markers of cell stress in the plasma of three recipients with various clinical histories. Early kinetics of C-peptide and MPs followed identical patterns during the first weeks after transplantation; a major increase probably reflected processes related to cell infusion and islet engraftment. Importantly in the case of rejection, MPs and C-peptide showed opposite patterns. A fall in C-peptide was associated with enhanced insulin needs. Our results suggested that a peak in MP levels might indicate rejection with prognotic value. Treatment of the loss of islet function by a new islet infusion or steroid therapy returned MP and C-peptide levels to their baselines with concomitant restoration of islet function. In the patient with suspected acute cellular rejection, MPs also appeared to be sensors of immunosuppressive steroid therapy.

Experimental and theoretical analysis of transport properties of core-shell wire light emitting diodes probed by electron beam induced current microscopy

We report a systematic experimental and theoretical investigation of core-shell InGaN/GaN single wire light-emitting diodes (LEDs) using electron beam induced current (EBIC) microscopy. The wires were grown by catalyst-free MOVPE and processed into single wire LEDs using electron beam lithography on dispersed wires. The influence of the acceleration voltage and of the applied bias on the EBIC maps was investigated. We show that the EBIC maps provide information both on the minority carrier effects (i.e. on the local p-n junction collection efficiency) and on the majority carrier effects (i.e. the transport efficiency from the excited region toward the contacts). Because of a finite core and shell resistance a non-negligible current redistribution into the p-n junction takes place during the majority carrier transport. A theoretical model for transport in a core-shell wire is developed, allowing to explain the dependence of the EBIC profiles on the experimental parameters (the electron beam acceleration voltage and the bias applied on the device) and on the structural parameters of the wire (core and shell resistance, shunt resistance, etc). Comparison between simulated and experimental profiles provides valuable information concerning the structure inhomogeneities and gives insight into the wire electrical parameters.

Is it worth assessing progress as early as week 2 to adapt antidepressive treatment strategy? Results from a study on agomelatine and a global meta-analysis

CONTEXT

A delay of 4-8weeks before modifying the prescribed antidepressant treatment is usually proposed when incomplete treatment response is observed. A number of studies nevertheless proposed that the lack of early improvement (usually 20% decrease of severity at week 2) is predictive of the absence of subsequent treatment response, potentially saving weeks of inadequate treatment, but with no information for non-interventional studies devoted to outpatients.

METHOD

Two thousand nine hundred and thirty-eight outpatients with major depressive disorder were included in a multicentre, non-interventional study, assessing at inclusion, week 2 and week 6, mood (QIDS-C, CGI, PGI and VAS) sleep (LSEQ) and functionality (SDS). All metrics at week 2 were tested for their capacity to predict response (and then remission) at week 6, all patients being treated by agomelatine. A meta-analysis of all studies (n=12) assessing the predictive role of improvement at week 2 was also performed, assessing specific effect size of published studies and the weight of the different parameters they used.

RESULTS

The QIDS-C and the CGI-I were the only instruments with an area under the curve over 0.7, with different cut-offs for treatment response and remission. A decrease of more than five points at the QIDS-C had the highest positive predictive value for treatment response, and a CGI-I over three had the highest negative predictive value, which would favour relying on the clinicians for warning (too high CGI-I), and on instruments for confidence (favourable decrease of the QIDS-C). The meta-analysis of all studies also detected a large effect size of early improvement, stressing how rating week 2 severity could be beneficial in clinical practice.

CONCLUSIONS

Previous reports stressing the interest of an assessment at week 2 were reinforced by the present results, which also defined more accurately what could be the most appropriate cut-offs, and how combining these early results could be more effective.

Evidence for humoral rejection of a pancreatic islet graft and rescue with rituximab and IV immunoglobulin therapy

We describe the decline in islet function, in relation to HLA sensitization, in an islet transplant recipient and the recovery of this function after treatment with anti-CD20 monoclonal antibody and IV immunoglobulins. A 51-year-old woman with type 1 diabetes received one intraportal islet infusion. Following this transplantation, she became insulin independent. A search for HLA antibodies by using an ELISA technique remained consistently negative for HLA class I and II. It was only 2 years after the islet transplantation that this search became positive against class II antigens, reaching a peak of reactivity concomitantly with the appearance of a deterioration of glucose control requiring low-dose insulin therapy. Luminex screening and single-antigen assays then revealed the presence of both nondonor-specific and donor-specific antibodies against HLA class II molecules. This immunization, already present in the pretransplant serum, had increased during the 6 months preceding the clinical deterioration. Since these data nevertheless pointed to antibody-mediated rejection of the islet allograft, treatment with anti-CD20 monoclonal antibody and IV immunoglobulins was initiated. One month later, the search by ELISA for antibodies against HLA class II antigens became negative, the Luminex tests normalizing more gradually. As the result of an improvement in glucose control, the patient was again insulin-free.

Quality of life after islet transplantation: data from the GRAGIL 1 and 2 trials

BACKGROUND

Rigorous assessment of health-related quality of life (HRQL) is mandatory to establish the benefits of islet transplantation.

METHODS

The 36-Item Short Form Health Survey (SF-36) and the Diabetes Quality of Life (DQOL) scales were completed by patients included in an Islet Transplantation Alone (ITA) trial (n = 10) and an Islet After Kidney (IAK) trial (n = 10).

RESULTS

The two populations differed by HRQL scores at baseline, with poorer scores in ITA patients. SF-36 scores for physical limitations, bodily pain, general health perception, social functioning, and health transition improved significantly in ITA patients 6 and 12 months post transplantation. The DQOL global score was significantly improved at 6 months and remained so at 12 months, because of a significant improvement in the dimensions of satisfaction and impact of diabetes. No improvement was observed in the IAK patients.

CONCLUSION

HRQL assessment may help in the selection of candidates with brittle diabetes for islet transplantation.

Proposed diagnostic criteria for apathy in Alzheimer's disease and other neuropsychiatric disorders

There is wide acknowledgement that apathy is an important behavioural syndrome in Alzheimer's disease and in various neuropsychiatric disorders. In light of recent research and the renewed interest in the correlates and impacts of apathy, and in its treatments, it is important to develop criteria for apathy that will be widely accepted, have clear operational steps, and that will be easily applied in practice and research settings. Meeting these needs is the focus of the task force work reported here. The task force includes members of the Association Française de Psychiatrie Biologique, the European Psychiatric Association, the European Alzheimer's Disease Consortium and experts from Europe, Australia and North America. An advanced draft was discussed at the consensus meeting (during the EPA conference in April 7th 2008) and a final agreement reached concerning operational definitions and hierarchy of the criteria. Apathy is defined as a disorder of motivation that persists over time and should meet the following requirements. Firstly, the core feature of apathy, diminished motivation, must be present for at least four weeks; secondly two of the three dimensions of apathy (reduced goal-directed behaviour, goal-directed cognitive activity, and emotions) must also be present; thirdly there should be identifiable functional impairments attributable to the apathy. Finally, exclusion criteria are specified to exclude symptoms and states that mimic apathy.

Tolerability of enteric-coated mycophenolate sodium to 1 year in combination with cyclosporine and corticosteroids in renal transplant recipients

Enteric-coated mycophenolate sodium (EC-MPS) is therapeutically equivalent to mycophenolate mofetil, but delays release of mycophenolic acid until it reaches the small intestine. De novo renal transplant patients taking part in a 12-month, multicenter, randomized study received cyclosporine microemulsion (CsA-ME, early or delayed to day 6), EC-MPS, steroids, and interleukin-2 antagonist induction. Tolerability data relating to EC-MPS are reported. Ninety-seven patients were randomized to early CsA-ME and 100 patients to delayed CsA-ME. Median daily dose of EC-MPS was 1440 mg at all time points throughout the 12-month period. The most frequently reported adverse events were constipation, anemia, urinary tract infection, abdominal pain, leukopenia, and cytomegalovirus infection; there were four malignancies. Fifty patients (24.6%) discontinued EC-MPS prematurely by 12 months, including 42 patients (84%) who discontinued owing to adverse events. No patient discontinued treatment because of gastrointestinal adverse events. Two-thirds of patients (137 [67.5%]) maintained full EC-MPS dose throughout the 12-month study and did not require any dose reduction or dose interruption. EC-MPS is well tolerated in de novo renal transplant recipients when administered in combination with CsA-ME and steroids, with low rates of dose reductions or interruptions. Gastrointestinal adverse events were responsible for dose reduction or interruption in only 5% of patients.

A positron emission tomography (PET) study of cerebral dopamine D2 and serotonine 5-HT2A receptor occupancy in patients treated with cyamemazine (Tercian)

RATIONALE

Cyamemazine (Tercian) is an antipsychotic drug with anxiolytic properties. Recently, an in vitro study showed that cyamemazine possesses high affinity for serotonin 5-HT(2A) receptors, which was fourfold higher than its affinity for dopamine D(2) receptors (Hameg et al. 2003).

OBJECTIVES

The aim of this study is to confirm these previous data in vivo in patients treated with clinically relevant doses of Tercian.

METHODS

Eight patients received 37.5, 75, 150 or 300 mg/day of Tercian depending on their symptomatology. Dopamine D(2) and serotonin 5-HT(2A) receptor occupancies (RO) were assessed at steady-state plasma levels of cyamemazine with positron emission tomography (PET), using [(11)C]raclopride and [(11)C]N-methyl-spiperone, respectively. The effective plasma level of the drug leading to 50% of receptor occupancy was estimated by fitting RO with plasma levels of cyamemazine at the time of the PET scan.

RESULTS

Cyamemazine induced near saturation of 5-HT(2A) receptors (RO=62.1-98.2%) in the frontal cortex even at low plasma levels of the drug. On the contrary, occupancy of striatal D(2) receptors increased with plasma levels, and no saturation was obtained even at high plasma levels (RO=25.2-74.9%). The effective plasma level of cyamemazine leading to 50% of D(2) receptor occupancy was fourfold higher than that for 5-HT(2A) receptors. Accordingly, individual 5-HT(2A)/D(2) RO ratios ranged from 1.26 to 2.68. No patients presented relevant increased prolactin levels, and only mild extrapyramidal side effects were noticed on Simpson and Angus Scale.

CONCLUSION

This in vivo binding study conducted in patients confirms previous in vitro findings indicating that cyamemazine has a higher affinity for serotonin 5-HT(2A) receptors compared to dopamine D(2) receptors. In the dose range 37.5-300 mg, levels of dopamine D(2) occupancy remained below the level for motor side effects observed with typical antipsychotics and is likely to explain the low propensity of the drug to induce extrapyramidal side effects.

A case of arthritis caused by cytomegalovirus after kidney transplantation

Cytomegalovirus (CMV) is the leading cause of infectious complications after organ transplantation. We report the case of a 55-year-old renal transplant recipient who presented with CMV infection 2 months after transplantation. During oral ganciclovir treatment (5 weeks after interruption of intravenous ganciclovir), he experienced a sharp pain in the right shoulder. Examination was normal, but CMV antigenemia remained positive with 30 cells/300,000. He underwent a shoulder puncture, which confirmed the presence of CMV in the articular fluid after evaluation by polymerase chain reaction gene amplification. The patient recovered from his arthritis of the shoulder, and antigenemia became negative after 3 weeks of parenteral ganciclovir. We describe a CMV arthritis that occurred despite a curative treatment for CMV disease, and comment on the pathogenesis of this infection, the pharmalogical failure, and dosing or treatment duration.

[Definitions and recommendations for studying the delay of antidepressant action. Part 3: methodological aspects]

AIMS

To provide a journal publishing all literature relevant to the time of response to antidepressants, in order to find out any existing consensus which might bring in fine recommendations for a thorough study of the concept. Three sections corresponding to 3 articles surveyed by the Encephale deal with the pharmacological, clinical, and metho-dological aspects.

METHOD

A group of experts (see conclusion) was trained on the initiative of the authors, following a think-talk at a meeting of scientific learned societies (FUAG and AFPB in particular). Dr Sophie Banzet, from the Boehringher-Ingelheim Laboratories, attended the meeting as a partner supporting this project. The article tries to give the most faithfull coverage of the main topics discussed by the group of experts, allowing each author to highlight his own contribution after the rereading of his text by the two other authors of the group. Are also included in the analysis the major studies published in the literature at the date when the present article was submitted.

RESULTS AND CONCLUSION

There are no unequivocal criteria to assess or identify the time of response to antidepressants on a pharmacological level. In fact, the criteria depend on the symptomatic impact of the antidepressant while depression cannot be defined as a single-symptom pathology. The criteria retained for assessment depend on the chosen definition which is: either quantitative (patients profiles global method), or qualitative (sympto-matic approach). One should discriminate between the assessment of the time of response and the stage proving the efficacy of the antidepressant. The threshold proposed for efficacy is based on the values of the thresholds used in clinical tests and in literature, as well as those commonly accepted by the various drug agencies. Choosing the variable for the response to antidepressants must take into account the popu-lation of patients responding to treatment. A consensus on the choice of comparators can be observed in studies on the time of response to antidepressants: using a placebo is necessary. The active reference product depends on the population concerned. The statistical methods which have been used, in particular the survival analysis methods are very useful indeed but they entails loss of information and must be completed by tests which, though simpler, allow simpler conclusions (such as c(2)). Lastly, the experimental level, which aims to assess the time of response, remains by far the most difficult part. It is still unsolved and the study aiming to prove efficacy. We have not included the considerations on this particular point as this would require an article in its own right. The cognitive symptoms belonging to the DSM IV diagnosis criteria in major depressive periods can help to build new tools.

Reduction of extracellular dopamine and metabolite concentrations in rat striatum by low doses of acute cyamemazine

The low incidence of extrapyramidal effects with atypical neuroleptics has been ascribed to their 5-HT(2A)- and 5-HT(2C)-serotonin receptor antagonistic properties. On the other hand, the acute increase in striatal dopamine release by submaximal dopamine D(2) autoreceptor blockade can be respectively reduced and increased by 5-HT(2A)- and 5-HT(2C)-antagonists. Cyamemazine is a neuroleptic D(2)- and 5-HT(2A)-receptor antagonist, with small antagonistic activity at 5-HT(2C) receptors and low incidence of extrapyramidal side effects. Therefore, submaximal cyamemazine was tested in rats for its acute action on the extracellular concentrations of dopamine and dopamine metabolites (DOPAC: 3,4,dihydroxyphenylacetic acid and HVA: 4-hydroxy-3-methoxy-phenyl-acetic acid) in the corpus striatum. The serotonin metabolite 5-HIAA (5-hydroxy-indole-acetic acid) was measured in parallel. Rats prepared for microdialysis (striatum) were intraperitoneally given cyamemazine 1 mg/kg, 5 mg/kg or vehicle ( n=4 in each group). Dopamine, DOPAC, HVA and 5-HIAA concentrations in perfusates under basal conditions and after stimulation by high K(+) were measured by HPLC coupled to electrochemical detection. Cyamemazine 1 mg/kg significantly reduced extracellular concentrations of basal dopamine (-77%), DOPAC (-54%), HVA (-54%) and 5-HIAA (-65%). No such effects were seen with the dose of cyamemazine 5 mg/kg or for K(+)-evoked dopamine release. In conclusion, submaximal cyamemazine can acutely reduce basal dopamine release and metabolism in the rat striatum. Such unusual action can be explained by the original pharmacological profile of cyamemazine (potent D(2)- and 5-HT(2A)-antagonist, with small antagonistic activity at 5-HT(2C) receptors). Further experiments are required to explain the low incidence of extrapyramidal side actions with cyamemazine.

[Focus on Islets of Langerhans transplantation]

INDICATIONS

There are two types of indications for Langerhans islets transplantation, patients with type 1 diabetes mellitus who have a functional kidney graft but who cannot be candidates for total pancreas transplantation, and soon, patients without renal failure who develop particularly uncontrollable diabetes mellitus.

SEVERAL BASIC CONDITIONS

Several conditions are required for the success of Langerhans islet transplantation: a laboratory with demonstrated skill is isolating islets, a sufficiently large number of islets for injection (600,000 for a 60-kg patient), fresh islets harvested within less than 24 hours before transplantation, effective immunosuppressive treatment with no toxic effect on Langerhans islets. The injection is a simple procedure performed under local anesthesia via transhepatic catheterization of the portal vein.

RESULTS

Through 2000, 10% to 20% of implanted grafts were functional at 1 year. Islets survival has exceeded 80% at 1 year. The gold standard for success is withdrawal of insulin therapy and normal glucose control. Islets grafts will undoubtedly become the next important step in the treatment of type 1 diabetes mellitus, but other techniques are also envisaged for the future.

Human islet transplantation network for the treatment of Type I diabetes: first data from the Swiss-French GRAGIL consortium (1999-2000). Groupe de Recherche Rhin Rhĵne Alpes Genève pour la transplantation d'Ilots de Langerhans

AIMS/HYPOTHESIS

Improvements in islet transplantation require clinical series large enough to implement controlled new strategies. The goal of this study was to demonstrate the feasibility of a multicentre network for islet transplantation in Type I (insulin-dependent) diabetic patients.

METHODS

The five centres (Besançon, Geneva, Grenoble, Lyon, Strasbourg) of the GRAGIL network allow pancreas procurement, recipient recruitment, transplantation procedure and follow-up. Islet isolation is, however, performed in one single laboratory (Geneva). Pancreata were procured in each of the five centres and transported to Geneva with an ischaemia time of less than 8 hours. Islets were isolated using a standard automated method. If the islet number was too low for a graft (< 6,000 Islet-equivalent/kg), islets were cultured up to 12 days until another isolation was possible. Islets were transplanted by percutaneous transhepatic intraportal injection. Immunosuppression consisted of cyclosporine, mycophenolate mofetil, steroids and an anti-interleukin 2 receptor antibody.

RESULTS

From March 1999 to June 2000, 56 pancreata procurements were performed with an average yield of 234500 islet-equivalent, with 32 preparations over 200000 islet-equivalent. Ten C-peptide negative Type I diabetic patients (5 men and 5 women, median age 44 years, median diabetes duration 29 years) with an established kidney graft (> 6 months) received 9,030 +/- 1,090 islet-equivalent/kg with a median purity of 63 %. The number of pancreata required for each graft was 1 (n = 5) or 2 (n = 5). At the completion of a 12 month follow-up, we observed 0% primary nonfunction, 50% graft survival and 20% insulin-independence.

CONCLUSIONS/INTERPRETATION

This study demonstrates the interest and the feasibility of a multicentre collaboration in human islet transplantation.

Urinary F2-isoprostanes formation in kidney transplantation

BACKGROUND

Oxygen free-radical mediated lipid peroxidation has been implicated in many diseases such as chronic renal failure, hemodialysis and chronic kidney transplant rejection. However, insight into the role of free radical generation in kidney transplantation has been constrained by the limitations of current indexes of oxidant stress in vivo. Isoprostaglandin F2alpha type-III (iPF2alpha-III, formerly known as 8-iso-prostaglandin F2alpha) is emerging as a reliable marker of oxidant stress in vivo. The purpose of our study was to investigate iPF2alpha-III formation as an index of lipid peroxidation in the 5 d following kidney transplantation.

METHODS

Urinary iPF2alpha-III measurements were performed by enzyme immunoassay from day I to 5 in 11 patients undergoing kidney transplantation. Results were compared with 11 healthy volunteers matched in sex, age and cigarette smoking.

RESULTS

Urinary excretion of iPF2alpha-III at day 1 did not significantly differ between control and transplant group (111 +/- 17 vs. 92 +/- 10 pM/ mM creatinine, respectively, NS). Urinary iPF2alpha-III levels did not differ between day 1 to 5, and were not correlated to cold ischaemia time.

CONCLUSION

Our study shows no evidence of enhanced lipid peroxidation in the first 5 d following kidney transplantation.

[Management of oncocytoma in transplanted kidney]

The authors report a case of oncocytoma arising in a transplanted kidney. The diagnostic and therapeutic management is discussed and compared to the limited data reported in the literature on this subject. Immunosuppression of renal transplant recipients does not appear to increase the incidence of graft tumours, but, in the authors' opinion, modifies the conservative attitude generally proposed for this type of tumour.

Profiles and prognostic values of LDH isoenzymes in patients with non-Hodgkin's lymphoma

Serum lactic dehydrogenase (LDH) is an important prognostic factor in patients with non-Hodgkin's lymphoma (NHL). We have examined the LDH isoenzyme content in serum and CSF of patients with NHL, at diagnosis and at relapse. In patients with increased serum LDH at diagnosis, the percentage of isoenzyme 2 was increased in 52% of patients and the absolute value of isoenzyme 3 was increased in 64% of patients. In relapsing patients these values were respectively 69% and 65%. Conversely in patients with increased serum LDH due to myeloid regeneration after chemotherapy, isoenzymes 4 and 5, but not isoenzymes 2 or 3, were increased. High absolute values of isoenzyme 3 were correlated with an altered performance status, advanced tumor stage, and aggressive histology whereas high isoenzyme 2 percentages were correlated with altered performance status only. Among patients with high total serum LDH, a high content of isoenzyme 2 and a high absolute value of isoenzyme 3 were correlated with high serum levels of TNFalpha and TNF receptor p75. Analysis of total LDH and LDH isoenzyme profiles in CSF did not reveal any correlation with meningeal involvement by lymphoma. High isoenzyme 2 percentages and high absolute values of isoenzyme 3 in serum were both significantly associated with a shorter freedom-from-progression and overall survival. Isoenzyme 3 remained a prognostic factor for survival even when considering only patients with high total serum LDH at diagnosis. We conclude that there are some characteristic serum LDH isoenzyme profiles in patients with NHL and that some of these specific alterations may help refine the prognostic value of total serum LDH.

[Risperidone-induced tardive dystonia: a case of torticollis]

Tardive dystonia is one of the most serious adverse events of typical neuroleptic treatments. They differ from tardive dyskinesia by their clinical and evolutive features. The occurrence of tardive dystonia due to new antipsychotics remained unknown. For the first time in the literature, we report a case of typical tardive dystonia occurring in a young male schizophrenic patient treated for 8 months with risperidone. No remission was observed despite several therapeutics including botulinic toxin.

[Economic contribution of mofetil mycofenolate as preventive immunosuppressive treatment after renal transplantation from cadaver]

OBJECTIVES

The economic impact resulting from the clinical consequences of immunosuppressive strategy using mycophenolate mofetil in new renal transplant recipients was conducted considering the viewpoint of the health insurance system.

METHODS

The analysis was based on the results of three controlled randomized double-blind clinical trials comparing mycophenolate mofetil with placebo or azathioprine in 1003 out of 1493 included patients respectively. Health care costs associated with each event were determined by 7 French experts in renal transplantation working in six different hospitals. Direct cumulative costs for each strategy were compared.

RESULTS

The studies demonstrated a difference in the incidence of acute rejection and treatment failures whatever the cause. The three trials showed that, compared with current strategies, use of mycophynolate mofetil in the immunosuppression protocol generated a 19 to 38% cost reduction during the 6 months after transplantation. Cost reduction resulted from lower incidence of acute rejection and the subsequent nephrectomics and dialysis sessions. The sensitivity analysis on the most important cost factors-cost of hospitalization per day and number of hospitalization days-confirmed strength of the results.

CONCLUSION

Use of mycophenolate mofetil in the immunosuppressive prophylaxis protocol after renal transplantation allows a reduction in the direct costs during the 6 months following transplantation.

[Cytolytic hepatitis during treatment with phenothiazines: apropos of a case]

In contrast to the well known chlorpromazine-induced cholestatic hepatitis, we report the case of a schizophrenic patient who presents a cytolytic hepatitis, without any prior hepatic disease. Mr G. was first hospitalized for depressive symptomatology. A pseudo-nevrotic schizophrenia was diagnosed. Pretherapeutic clinical and biological data were normal. A treatment with chlorpromazine 400 mg/day was given. At day 8, the patient was still anxious and began to be agitated. An increase to 500 mg/day of chlorpromazine posology and an addition of haloperidol 200 mg/day was implemented. At day 10, the following clinical symptoms appeared: 38.6 degrees C fever; headache; myalgia; epigastralgia and hypocondrium pain. Biological hepatitis disturbances (ALAT, 984 U/L; ASAT, 414 U/L) and hypereosinophilia with normal white cell count were found. Clinical and biological investigations were normal. Blood-culture, A, B, C hepatitis, HIV and CMV serologies were negative. Neuroleptic treatment was discontinued. Evolution to normality of the disturbances and biological data suggested a cytolytic hepatitis. Mr G... remained treated with flupentixol without side-effects. Phenothiazine-induced cholestatis is frequent, mild, and recovers spontaneously. The biological mechanism is supposed to be immunologic. Prevalence of biological hepatic disturbances is 10 to 20% with chlorpromazine in long-term treatment. More often, symptomatology is the same; jaundice, pruritus, abdominal pain, fever. Although pharmacological data suggest for a cytotoxic activity of phenothiazines, cytolytic hepatitis is poorly described. Maximum range of transaminase blood level reported in previous studies is about 400 U/l. This level is not clearly correlated with hepatic cell lysis. Few cases of hepatic necrosis have been reported. In all cases, preexistent hepatic injuries were observed. Chlorpromazine-induced cytolytic hepatitis is uncommon and cholestatic hepatitis mild. Biological hepatic parameters investigations remain necessary during neuroleptic treatment.

[Hematotoxicity caused by azathioprine genetically determined and aggravated by xanthine oxidase deficiency in a patient following renal transplantation]

Azathioprine is an immunosuppressor used with ciclosporin and corticosteroids after organ transplantation. Azathioprine is rapidly transformed into 6-mercaptopurine which in turn is metabolized by three competitive pathways: a) intracellular hypoxanthine guanine phosphoribosyl transferase leads to 6-thioguanine nucleotides which can damage chromosome DNA; b) thiopurine methyltransferase produces inactive methylated derivatives; c) xanthine oxidase produces thiouric acid. Due to inter-individual variations in the later two pathways, azathioprine dose must be adapted to each patient. A 48-year-old female patient underwent renal transplantation in 1994 and was given immunosuppressive therapy combining thymoglobulins, azathioprine and ciclosporin. Severe leukopenia (< 3000/mm3) occurred on day 5 requiring withdrawal of azathioprine. Known hypouricaemia (< 50 mumol/l) suggested xanthine oxidase deficiency. Laboratory results confirmed xanthine oxidase deficiency and also revealed reduced thiopurine methyltransferase activity (14.9 pmol/h/mg Hb). Azathioprine toxicity was confirmed by regression of the leukopenia after withdrawal and recurrence at rechallenge. Xanthine oxidase deficiency occurs in 2% of the general population. Reduced thiopurine methyltransferase activity affects 11% of the population. The combined presence of these two genetic anomalies led to early and sudden intolerance to azathioprine and emphasize the need to develop new immunosuppressor agents degraded by other metabolic pathways.

Beneficial effect of one HLA haplo- or semi-identical transfusion versus three untyped blood units on alloimmunization and acute rejection episodes in first renal allograft recipients

Acute allograft rejection is the major risk factor of renal function decline and graft loss. Beside histocompatibility matches and pharmacological immunosuppression, blood transfusion is empirically used to detect responder subjects and to induce immune tolerance. Alloimmunization associated with blood transfusions readily detected by anti-HLA antibodies could induce acute vascular rejection episodes during the early period after grafting. Our open prospective study was aimed at analyzing the 1 year follow-up of 105 successive first cadaver renal transplant recipients according to the transfusion protocol as assessed by anti-HLA antibody production, acute rejection episodes, and graft survival. Our conventional transfusion protocol involved 3 nonphenotyped blood transfusions set up at least 20 days before grafting in a control cohort (group A) and was compared with a single pretransplant HLA haplo- or semi-identical blood transfusion in a successive group of patients (group B). Our results suggest that both protocols were associated with similar 1-year graft survivals (> 96% in both groups) and number of patients experiencing rejection episodes (20.7% in group A; 9.6% in group B; P NS). HLA haplo- or semi-identical transfusion was significantly beneficial in naive patients without previous alloantigen contact by pregnancy or blood transfusions during dialysis. Naive patients in group B did not develop post-transfusion anti-HLA antibodies compared to naive patients in group A (16.6%; P < 0.001), and they experienced significantly less acute rejection episodes (2.7%) compared to group A naive patients (20.8%; P = 0.02).

[Influence of kidney procurement techniques on urologic and vascular complications of the transplantation]

Surgical complications of renal transplantation, rejection and infectious diseases are factors contributing to poor renal graft survival. Factors directly concerning the donor can be involved in graft failure: age, medical history, causes of donor brain death. Urologic or arterial anatomic variations are often the source of difficult surgical conditions during renal transplantation. Technical errors during graft procurement must be avoided such as excess of traction or coagulation. Failure in perfusion preservation. As few renal grafts are available, it is thus essential to obtain optimal conditions to avoid failure in cadaver donor graft linked to technical errors during organ procurement.

[Open trial of carbamazepine in the prevention of recurrence of bipolar disorder in adolescents]

While the existence of bipolar disorder in children and adolescents is now recognized, the prevalence of the disorder is still unknown, although it is clear that its' incidence increases markedly at puberty. The risks inherent in the course of the disorder, including recurrence and suicidal gestures, highlight the importance of its early recognition; however, diagnosis and identification of predictive factors in childhood bipolar disorder is problematic. Given the development of new mood-regulating psychopharmacological treatments for adults, early diagnosis in children is even more important. For children and adolescents, previous studies have shown the efficacy of lithium in the prevention of recurrence of bipolar disorder, but only over short periods of time. There are very few published studies on the use of carbamazepine in bipolar disorder; those that exist are most often single case studies. The authors present the results of an uncontrolled study of 11 patients, aged 10 to 17 years, diagnosed with bipolar according to DSM III-R criteria. These patients were treated with carbamazepine for a period of over 1 year. Two cases, especially noteworthy for their improvement, are presented in greater detail. A positive response was considered to have been obtained if a period greater than 1 year of normal affect was obtained. According to this criterion, seven patients were positive responders, two were moderate responders and two did not respond to treatment. Tolerance to the medication was good; in no cases it was necessary to interrupt treatment. Principle adverse side effects were biological, involving an increase in a single liver enzyme. Comparison among positive, moderate and non responders did not reveal any criteria predictive of therapeutic effectiveness. Despite methodological difficulties, these data point the importance of developing controlled studies with carbamazepine in the prevention of recurrence of bipolar disorder.

[Renal transplantectomy: surgical technics and results. Apropos of 60 patients]

Nephrectomy of a non-functioning renal transplant after renal transplantation is a delicate operation which the authors evaluate on the basis of a retrospective analysis of 62 patients. A review of the literature helps to more clearly define the indications, optimal time of the operation and the operative technique. A subcapsular approach, by simplifying the operation, constitutes an important factor in reducing the operative morbidity in the late forms. "Early" transplantectomies are often more serious because of the recently operated patient's fragile status and immunosuppression, responsible for frequent infectious complications. Transplantectomy should therefore not be delayed once the permanent loss of transplant function has been confirmed.

[Primary microvascular lesions of the kidney or pre-hypertensive nephroangiosclerosis. 25 cases]

Isolated non inflammatory lesions of renal microarteries (eventually with mild thickening of tubular basement membranes, but with negative immunofluorescent glomerular studies) were observed in 25 patients (22 males) in whom renal biopsy have been performed for proteinuria (P). Selection criteria were: pathological lesions by definition; absence of hypertension (HT) in clinical and at the time of biopsy; minimum follow up of 4 years after the first statement of the proteinuria (4 to 29 years; mean 14 years). Three groups have been isolated: 1. 3 patients have had an acute glomerulonephritis followed by disappearance of proteinuria. It reappears 1 to 5 years later. HT was discovered 2, 8 and 11 years after the proteinuria. Renal failure occurred 1 and 3 years after HT. 2. 14 patients had hereditary or acquired vascular risk factors (obesity, smoking, ethylism). In 7, HT occurred 3 to 15 years after P. In 2, renal failure occurred 4 to 8 years later. 3. 8 patients had no vascular risk factor; in 3 of them Ht developed 7, 13 and 20 years after the first statement. A positive immunofluorescence with IgM or C3 on renal arterioles had been found in only 3 of the 10 patients who in group 2 and 3 became hypertensive. A proteinuria may precede the occurrence of HT without being induced by glomerulonephritis. Group 2 and 3 suggest that these renal lesions of arterial sclerosis precede and may be a factor of HT. Indeed, this entity may be considered as a prehypertensive condition.