A Rapid CRISPR/Cas-based Mutagenesis Assay in Zebrafish for Identification of Genes Involved in Thyroid Morphogenesis and Function.

The foregut endoderm gives rise to several organs including liver, pancreas, lung and thyroid with important roles in human physiology. Understanding which genes and signalling pathways regulate their development is crucial for understanding developmental disorders as well as diseases in adulthood. We exploited unique advantages of the zebrafish model to develop a rapid and scalable CRISPR/Cas-based mutagenesis strategy aiming at the identification of genes involved in morphogenesis and function of the thyroid. Core elements of the mutagenesis assay comprise bi-allelic gene invalidation in somatic mutants, a non-invasive monitoring of thyroid development in live transgenic fish, complementary analyses of thyroid function in fixed specimens and quantitative analyses of mutagenesis efficiency by Illumina sequencing of individual fish. We successfully validated our mutagenesis-phenotyping strategy in experiments targeting genes with known functions in early thyroid morphogenesis (pax2a, nkx2.4b) and thyroid functional differentiation (duox, duoxa, tshr). We also demonstrate that duox and duoxa crispants phenocopy thyroid phenotypes previously observed in human patients with bi-allelic DUOX2 and DUOXA2 mutations. The proposed combination of efficient mutagenesis protocols, rapid non-invasive phenotyping and sensitive genotyping holds great potential to systematically characterize the function of larger candidate gene panels during thyroid development and is applicable to other organs and tissues.

Determination of irinotecan and SN38 in human plasma by TurboFlow™ liquid chromatography-tandem mass spectrometry.

Irinotecan is a cytotoxic agent used in the treatment of metastatic colorectal cancer. Irinotecan is a prodrug when is converted in vivo to an active metabolite SN38, which has potent pharmacological activity. SN38 is then inactivated and excreted as SN38-glucuronide. High-performance liquid chromatography-mass spectrometry is a widely used bioanalysis technique that can be coupled to the turbulent-flow extraction line to shorten preparation time. A technique was developed to quantify irinotecan and its metabolite by liquid chromatography-tandem mass spectrometry coupled with a turbulent-flow online extraction method. Assays were performed on 100 µL of plasma after protein precipitation. The supernatant is injected directly into the extraction column, transferred to the chromatographic column, and analyzed by tandem mass spectrometry. Linearity, reproducibility and repeatability of the method were validated on a concentration range of 25-2500 ng/mL for irinotecan and 5-500 ng/mL for SN38. For the low limit of quantification of irinotecan and SN38, precision is 6.31% and 8.73%, and accuracy is 84.0% and 91.8%, respectively. The SN38-glucuronide determination protocol included a hydrolyzation step. This method was successfully used to quantify irinotecan, SN38 and SN38-G in human plasma in a clinical trial.

[Spondylodiscitis in children: a review. A propos of two cases]. / La spondylodiscite chez l'enfant: a propos de deux observations.

Spondylodiscitis is defined as an infection of the intervertebral disc and the adjacent vertebral bodies. It represents, at the most, 2-4% of osteoarticular infections in children and its clinical presentation is often insidious. The specific condition of the young child (isolated discitis) is explained by some anatomical peculiarities. We report two cases of spondylodiscitis in children of different ages and review the pediatric characteristics, the role of imaging, the bacteriological diagnosis and the management of this disease.

Hyperosmotic stress induces cell cycle arrest in retinal pigmented epithelial cells.

Osmotic changes occur in many tissues and profoundly influence cell function. Herein, we investigated the effect of hyperosmotic stress on retinal pigmented epithelial (RPE) cells using a microarray approach. Upon 4-h exposure to 100 mM NaCl or 200 mM sucrose, 79 genes were downregulated and 72 upregulated. Three gene ontology categories were significantly modulated: cell proliferation, transcription from RNA polymerase II promoter and response to abiotic stimulus. Fluorescent-activated cell sorting analysis further demonstrated that owing to hyperosmotic stimulation for 24 h, cell count and cell proliferation, as well as the percentage of cells in G0/G1 and S phases were significantly decreased, whereas the percentage of cells in G2/M phases increased, and apoptosis and necrosis remained unaffected. Accordingly, hyperosmotic conditions induced a decrease of cyclin B1 and D1 expression, and an activation of the p38 mitogen-activated protein kinase. In conclusion, our results demonstrate that hypertonic conditions profoundly affect RPE cell gene transcription regulating cell proliferation by downregulation cyclin D1 and cyclin B1 protein expression.

Evidence for a differential opioidergic involvement in the analgesic effect of antidepressants: prediction for efficacy in animal models of neuropathic pain?

BACKGROUND AND PURPOSE: Antidepressants are one of the recommended treatments for neuropathic pain. However, their analgesic action remains unpredictable, and there are no selection criteria for clinical use. Better knowledge of their mechanism of action could help highlight differences underlying their unequal efficacy. EXPERIMENTAL APPROACH: We compared the activity of a tricyclic antidepressant (clomipramine) with selective 5-HT and noradrenaline reuptake inhibitors (milnacipran and duloxetine) in streptozocin-induced diabetic and chronic constriction nerve injury-induced neuropathic rats, after repeated injections. We looked for an opioidergic mechanism in their action. KEY RESULTS: Abolition of mechanical hyperalgesia was observed in mononeuropathic rats after five injections of clomipramine (5 mg·kg(-1) , s.c.) and milnacipran (10 or 20 mg·kg(-1) , i.p.) and in diabetic rats after clomipramine. An additional antinociceptive effect was obtained with five injections of duloxetine (3 mg·kg(-1) , i.p.) in both models and milnacipran (10 mg·kg(-1) , i.p.) in diabetic rats. These effects were observed with plasma antidepressant concentrations similar to those found in patients treated for neuropathic pain. Naloxone (1 mg·kg(-1) , i.v.) only suppressed the anti-hyperalgesic effects of clomipramine in both models of pain and of milnacipran in the traumatic model. CONCLUSIONS AND IMPLICATIONS: The opioid system appears to be involved in the mechanism of action of antidepressants that only have an anti-hyperalgesic effect but not in those that have a stronger (i.e. antinociceptive) effect. These differences between the antidepressants occurred whatever the aetiology of the neuropathy and, if confirmed in clinical trials, could be used to decide which antidepressant is administered to a patient with neuropathic pain.

Development of a Bayesian estimator for the therapeutic drug monitoring of mycophenolate mofetil in children with idiopathic nephrotic syndrome.

The use of mycophenolate mofetil (MMF) in children with idiopathic nephrotic syndrome (INS) is increasing. However, the clinical benefit of its monitoring has been scarcely studied, and little is known about its pharmacokinetics in this context. The objectives of the present study were: (i) to study and model the pharmacokinetics of mycophenolic acid (MPA; the active moiety of MMF) in paediatric patients with INS given MMF, at all stages of the disease; (ii) to develop a Bayesian estimator (MAP-BE) for individual inter-dose area under the concentration-time curve (AUC) prediction in this population, using a limited blood sampling strategy (LSS). Full-pharmacokinetic (PK) profiles of MPA collected in paediatric inpatients with INS already treated with a maintenance immunosuppressive therapy based on MMF (with no calcineurin inhibitors; CNI) were studied. A classical iterative two-stage (ITS) method was applied to model the data and develop MAP-BEs using a one-compartment open model where the absorption is described by a double gamma law allowing the description of a potential enterohepatic recirculation. The performance of the MAP-BE developed for individual exposure assessment was evaluated by the bias and precision of predicted AUCs with respect to measured, trapezoidal AUCs (reference value), and by the proportion of predicted AUCs with absolute error >20%. These PK tools were tested in an independent group of patients. Sixty PK profiles of MPA from children receiving MMF in association to corticosteroids or given alone were included in the study. Forty-five of these PK profiles were used to develop a PK model and a MAP-BE, and 15 for their validation. In the building group, the PK model fitted accurately the PK profiles of MPA: mean residual error of modelled vs. reference AUC was m±SD=-0.015±0.092 (range: -0.153 to 0.204). The MAP-BE which allowed the estimation of MPA AUC on the basis of a 20 min-60 min-180 min LSS was then developed. In the independent group of patients, its mean residual error vs. reference AUCs was m±SD=-0.036±0.145 (range: -0.205 to 0.189). Thus, a PK model and its derived MAP-BE for MMF (without any associated CNI) when given to children with INS have been developed. Clinical trials using these PK tools could test the potential impact of the therapeutic drug monitoring of MMF based on the AUC on the clinical evolution of INS.

Genome-wide gene expression profiling suggests distinct radiation susceptibilities in sporadic and post-Chernobyl papillary thyroid cancers.

Papillary thyroid cancers (PTCs) incidence dramatically increased in the vicinity of Chernobyl. The cancer-initiating role of radiation elsewhere is debated. Therefore, we searched for a signature distinguishing radio-induced from sporadic cancers. Using microarrays, we compared the expression profiles of PTCs from the Chernobyl Tissue Bank (CTB, n=12) and from French patients with no history of exposure to ionising radiations (n=14). We also compared the transcriptional responses of human lymphocytes to the presumed aetiological agents initiating these tumours, gamma-radiation and H(2)O(2). On a global scale, the transcriptomes of CTB and French tumours are indistinguishable, and the transcriptional responses to gamma-radiation and H(2)O(2) are similar. On a finer scale, a 118 genes signature discriminated the gamma-radiation and H(2)O(2) responses. This signature could be used to classify the tumours as CTB or French with an error of 15-27%. Similar results were obtained with an independent signature of 13 genes involved in homologous recombination. Although sporadic and radio-induced PTCs represent the same disease, they are distinguishable with molecular signatures reflecting specific responses to gamma-radiation and H(2)O(2). These signatures in PTCs could reflect the susceptibility profiles of the patients, suggesting the feasibility of a radiation susceptibility test.

Gene expression and the biological phenotype of papillary thyroid carcinomas.

The purpose of this paper is to correlate the molecular phenotype of papillary thyroid carcinoma (PTC) to their biological pathology. We hybridized 26 PTC on microarrays and showed that nearly 44% of the transcriptome was regulated in these tumors. We then combined our data set with two published PTC microarray studies to produce a platform- and study-independent list of PTC-associated genes. We further confirmed the mRNA regulation of 15 genes from this list by quantitative reverse transcription-PCR. Analysis of this list with statistical tools led to several conclusions: (1) there is a change in cell population with an increased expression of genes involved in the immune response, reflecting lymphocyte infiltration in the tumor compared to the normal tissue. (2) The c-jun N-terminal kinase pathway is activated by overexpression of its components. (3) The activation of ERKK1/2 by genetic alterations is supplemented by activation of the epidermal growth factor but not of the insulin-like growth factor signaling pathway. (4) There is a downregulation of immediate early genes. (5) We observed an overexpression of many proteases in accordance with tumor remodeling, and suggested a probable role of S100 proteins and annexin A2 in this process. (6) Numerous overexpressed genes favor the hypothesis of a collective migration mode of tumor cells.

Global profiling of genes modified by endoplasmic reticulum stress in pancreatic beta cells reveals the early degradation of insulin mRNAs.

AIMS/HYPOTHESIS: Pancreatic beta cells respond to endoplasmic reticulum (ER) stress by activating the unfolded protein response. If the stress is prolonged, or the adaptive response fails, apoptosis is triggered. We used a 'homemade' microarray specifically designed for the study of beta cell apoptosis (the APOCHIP) to uncover mechanisms regulating beta cell responses to ER stress. MATERIALS AND METHODS: A time course viability and microarray analysis was performed in insulin-producing INS-1E cells exposed to the reversible ER stress inducer cyclopiazonic acid (CPA). Modification of selected genes was confirmed by real-time RT-PCR, and the observed inhibition of expression of the insulin-1 (Ins1) and insulin-2 (Ins2) genes was further characterised in primary beta cells exposed to a diverse range of agents that induce ER stress. RESULTS: CPA-induced ER stress modified the expression of 183 genes at one or more of the time points studied. The expression of most of these genes returned to control levels after a 3 h recovery period following CPA removal, with all cells surviving. Two groups of genes were particularly affected by CPA, namely, those related to cellular responses to ER stress, which were mostly upregulated, and those related to differentiated beta cell functions, which were downregulated. Levels of Ins1 and Ins2 mRNAs were severely decreased in response to CPA treatment as a result of degradation, and there was a concomitant increase in the level of IRE1 activation. CONCLUSIONS/INTERPRETATION: In this study we provide the first global analysis of beta cell molecular responses to a severe ER stress, and identify the early degradation of mRNA transcripts of the insulin genes as an important component of this response.

Acetaminophen: a central analgesic drug that involves a spinal tropisetron-sensitive, non-5-HT(3) receptor-mediated effect.

The reversal of the antinociceptive effect of systemically administered acetaminophen (paracetamol) by intrathecal administration of the potent 5-HT(3) receptor antagonist tropisetron has been reported in rats subjected to the paw pressure test, suggesting that acetaminophen action is mediated through spinal 5-HT(3) receptors. However, more recent data, showing differences between the pharmacological profiles of various 5-HT(3) receptor antagonists, led us to reconsider the involvement of spinal 5-HT(3) receptors. To address this question, two different approaches were used: 1) electrophysiological recordings to assess whether acetaminophen directly modulates 5-HT(3) receptor activity and 2) pharmacological investigations with various 5-HT(3) receptor antagonists and spinal 5-HT(3) receptors antisense oligodeoxynucleotides (AODNs) to determine how those treatments might affect the antinociceptive action of acetaminophen. Electrophysiological studies demonstrated that acetaminophen had no direct agonist or antagonist effects on 5-HT(3A) receptors. Unlike tropisetron, other 5-HT(3) receptor antagonists, such as ondansetron and granisetron, injected intrathecally were unable to reverse the antinociceptive effect of acetaminophen. Moreover, pretreatment with AODNs did not reverse the acetaminophen-induced antinociceptive effect, although it suppressed the antinociceptive effect of m-chlorophenylbiguanide, a specific agonist of 5-HT(3) receptors, and significantly reduced (30%) the expression of these receptors in the dorsal horn of the spinal cord. These results suggest that acetaminophen-induced antinociceptive action involves a spinal tropisetron-sensitive receptor that is not the 5-HT(3) receptor and that remains to be identified.

Impact of deep freezing on the stability of 25 mg/ml vancomycin ophthalmic solutions.

For the treatment of certain eye infections, ophthalmic solutions 'laced' with 25 mg/ml vancomycin are sometimes prepared. Their physical and chemical stability and the maintenance of their sterility were studied after deep freezing at -20 +/- 2 degrees C and thawing, followed or not by refrigeration for 48 h at 4 +/- 2 degrees C. Physical and chemical analysis comprised visual inspection turbidity, determination of pH and osmolality, and assay of vancomycin by high performance liquid chromatography with ultraviolet detection. For microbiological analysis a 25 mg/ml vancomycin ophthalmic solution was filtered through two membranes and cultured on trypticase-soy and Sabouraud-glucose solid media. Any colonies were then counted. These physical, chemical and microbiological analyses demonstrated the stability of 25 mg/ml vancomycin ophthalmic solutions in 5% glucose deep frozen at -20 +/- 2 degrees C for 3 months. The vancomycin concentration varied by no more than 5% of the initial concentration, and no breakdown product was evidenced. Neither pH (mean=3.8 +/- 0.1) nor osmolality (mean=318.3 +/- 5.6 mOsm/kg) varied significantly, and remained compatible with intraocular administration. No particle or bacterial combination was found in the course of the study. The thawing procedure (at ambient temperature or under warm running water from a tap) did not modify the stability of the eye drops. Likewise, storage in a refrigerator for 48 h after thawing did not modify stability. The advantage of storing vancomycin 25 mg/ml ophthalmic solutions for 3 months in deep freeze is that a stock of chemically and microbiologically controlled preparations can be held ready for administration to patients, thereby allowing prompter dispensing, as the eye drops are not made up extemporaneously, while the improved control over production ensures that patients receive solutions of constant quality, as every batch prepared is systematically inspected.

Model of droplet dynamics in the Argentine ant Linepithema Humile (Mayr).

The formation of droplets of ants Linepithema humile (Mayr) is observed under certain experimental conditions: a fluctuating aggregate forms at the end of a rod and a droplet containing up to 40 ants eventually falls down. When the flux of incoming ants is sufficient, this process can continue for several hours, leading to the formation and fall of tens of droplets. Previous work indicates that the time series of drop-to-drop intervals may result from a nonlinear low-dimensional dynamics, and the interdrop increments exhibit long-range anticorrelations. A model of aggregation and droplet formation, based on experimental observations, is introduced and shown to reproduce these properties.

Multiple nonfunctional alleles of CCR5 are frequent in various human populations.

CCR5 is the major coreceptor for macrophage-tropic strains of the human immunodeficiency virus type I (HIV-1). Homozygotes for a 32-base pair (bp) deletion in the coding sequence of the receptor (CCR5Delta32) were found to be highly resistant to viral infection, and CCR5 became, therefore, one of the paradigms illustrating the influence of genetic variability onto individual susceptibility to infectious and other diseases. We investigated the functional consequences of 16 other natural CCR5 mutations described in various human populations. We found that 10 of these variants are efficiently expressed at the cell surface, bind [(125)I]-MIP-1beta with affinities similar to wtCCR5, respond functionally to chemokines, and act as HIV-1 coreceptors. In addition to Delta32, six mutations were characterized by major alterations in their functional response to chemokines, as a consequence of intracellular trapping and poor expression at the cell surface (C101X, FS299), general or specific alteration of ligand binding affinities (C20S, C178R, A29S), or relative inability to mediate receptor activation (L55Q). A29S displayed an unusual pharmacological profile, binding and responding to MCP-2 similarly to wtCCR5, but exhibiting severely impaired binding and functional responses to MIP-1alpha, MIP-1beta, and RANTES. In addition to Delta32, only C101X was totally unable to mediate entry of HIV-1. The fact that nonfunctional CCR5 alleles are relatively frequent in various human populations reinforces the hypothesis of a selective pressure favoring these alleles. (Blood. 2000;96:1638-1645)

Cloning of two human thyroid cDNAs encoding new members of the NADPH oxidase family.

Two cDNAs encoding NADPH oxidases and constituting the thyroid H(2)O(2) generating system have been cloned. The strategy of cloning was based on the functional similarities between H(2)O(2) generation in leukocytes and the thyroid, according to the hypothesis that one of the components of the thyroid system would belong to the gp91(Phox)/Mox1 gene family and display sequence similarities with gp91(Phox). Screening at low stringency with a gp91(Phox) probe of cDNA libraries from thyroid cells in primary culture yielded two distinct human cDNA clones harboring open reading frames of 1551 (ThOX1) and 1548 amino acids (ThOX2), respectively. The encoded polypeptides display 83% sequence similarity and are clearly related to gp91(Phox) (53 and 47% similarity). The theoretical molecular mass of 177 kDa is close to the apparent molecular mass of 180 kDa of the native corresponding porcine flavoprotein and the protein(s) detected by Western blot in dog and human thyroid. ThOX1 and ThOX2 display sequence similarities of 53% and 61%, respectively, with a predicted protein of Caenorhabditis elegans over their entire length. They show along their first 500 amino acids a similarity of 43% with thyroperoxidase. The corresponding genes of ThOX1 and ThOX2 are closely linked on chromosome 15q15.3. The dog mRNA expression is thyroid-specific and up-regulated by agents activating the cAMP pathway as is the synthesis of the polypeptides they are coding for. In human thyroid the positive regulation by cAMP is less pronounced. The proteins ThOX1 and ThOX2 accumulate at the apical membrane of thyrocytes and are co-localized with thyroperoxidase.

Experience with living related liver transplantation in 63 children.

The incentive to develop intrafamilial living related liver transplantation (LRLT) originated from the shortage of cadaveric organ supply. We report our experience with LRLT in 63 children during 1993-1998 in the frame of a protocol approved by the Ethics Committee of our Institution. During this period, 152 potential intrafamilial (mostly parental) donors were evaluated; 44 (28.5%) were excluded because of surgical (n = 4), medical (n = 39) or psychosocial reason (n = 1). Out of 108 who matched all medical, surgical and psychological criteria of selection, 45 did not underwent living donation because their child received a cadaveric graft (n = 22; LRLT was their second option) or because one of the parents who had both been selected was chosen [by the surgical team because of more favourable anatomy (n = 8) or by mutual agreement between the two parents (n = 5)]. Sixty-three living donors (36 mothers, 24 fathers, one grand mother, one aunt and one uncle) underwent procurement of the left lobe (n = 52), the left lobe extended to part of segment IV (n = 8) or a left hepatectomy (n = 3) without mortality or any serious morbidity. Their median hospital stay was 7 days (range: 6-12); full physical rehabilitation and normalization of liver tests were usually obtained within three weeks. Their psychological follow-up did not disclose any longstanding serious sequellae. The median age of the recipients was 13 months (range 5-189); 30 were younger than one year at the time of transplant. Their median weight was 8.1 kg (range: 4.3 to 60); 36 had an actual weight under 10 kg. Fifty-two received an ABO identical and 11 received an ABO compatible transplant. The native liver diseases were similar to common data in children, with biliary atresia being the most frequent indication (74.6%). The median weight of the graft was 260 gr (range: 138-680) with a median ratio between the graft weight and the recipient body weight of 3.17% (range: 0.75-8.08). All grafts were implanted orthotopically with semi-microvascular reconstruction of the hepatic vein, portal vein and hepatic artery [end to end anastomosis in 58 (2 arteries were reconstructed in 7 patients) and interposition of an iliac arterial allograft from the infrarenal aorta in 5]. Base line immunosuppression consisted of a triple drug regimen including steroids, Azathioprine and either Cyclosporine-Sandimmun (n = 9), Cyclosporine Microemulsion formulation-Neoral (n = 13) or Tacrolimus-Prograft (n = 41). Biopsy-proved acute rejection was treated with intravenous bolus of steroids; steroid-resistant acute rejection was treated by a switch from Cyclosporine to Tacrolimus or addition of Mycophenolate-Mofetil (Cellcept) in Tacrolimus treated patients. Actuarial patient survival was 91.8% and 89.6% after LRLT at one and five years post-transplant, respectively, and 87.5% and 82.8% at one and five years, respectively, in 90 patients who received a cadaveric graft during the same interval. Actuarial graft survival was 91.8% and 84.1% after LRLT at one and five years, respectively, and 76.4% and 73.3% at one and five years, respectively, after cadaveric transplants. Vascular thrombosis was observed in 9.5% of the patients (arterial thrombosis: 1.6%; portal thrombosis: 7.9%) without graft loss. Biliary complications were observed in 26.9% (bile leak from cut surface in 3.1%, anastomotic stricture in 22.2% and intrahepatic stricture in 1.5%); two patients died from septic shock possibly related to uncompletely relieved anastomotic stricture; all other biliary complications were successfully treated either conservatively or surgically. The incidence of acute rejection was 90.9% in 22 patients with Cyclosporine-based immunosuppression; acute rejection was corticoresistant in 50%. It was 46.3% in 41 patients with Tacrolimus-based immunosuppression (64% with Prograft in capsules and 18.7% with Prograft in granules); no acute rejection was corticoresistant. (ABSTRACT TRUNCATED)

Multiple charged and aromatic residues in CCR5 amino-terminal domain are involved in high affinity binding of both chemokines and HIV-1 Env protein.

CCR5 is a functional receptor for MIP-1alpha, MIP-1beta, RANTES (regulated on activation normal T cell expressed), MCP-2, and MCP-4 and constitutes the main coreceptor for macrophage tropic human and simian immunodeficiency viruses. By using CCR5-CCR2b chimeras, we have shown previously that the second extracellular loop of CCR5 is the major determinant for chemokine binding specificity, whereas the amino-terminal domain plays a major role for human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus coreceptor function. In the present work, by using a panel of truncation and alanine-scanning mutants, we investigated the role of specific residues in the CCR5 amino-terminal domain for chemokine binding, functional response to chemokines, HIV-1 gp120 binding, and coreceptor function. Truncation of the amino-terminal domain resulted in a progressive decrease of the binding affinity for chemokines, which correlated with a similar drop in functional responsiveness. Mutants lacking residues 2-13 exhibited fairly weak responses to high concentrations (500 nM) of RANTES or MIP-1beta. Truncated mutants also exhibited a reduction in the binding affinity for R5 Env proteins and coreceptor activity. Deletion of 4 or 12 residues resulted in a 50 or 80% decrease in coreceptor function, respectively. Alanine-scanning mutagenesis identified several charged and aromatic residues (Asp-2, Tyr-3, Tyr-10, Asp-11, and Glu-18) that played an important role in both chemokine and Env high affinity binding. The overlapping binding site of chemokines and gp120 on the CCR5 amino terminus, as well as the involvement of these residues in the epitopes of monoclonal antibodies, suggests that these regions are particularly exposed at the receptor surface.

Pediatric liver transplantation: from the full-size liver graft to reduced, split, and living related liver transplantation.

Between 1984 and 1996, the authors performed 499 liver transplants in 416 children less than 15 years old. The overall patient survival at 10 years was 76.5%. It was 71.3% for the 209 children grafted in 1984-1990; 78.5% for biliary atresia (n = 286), 87.3% for metabolic diseases (n = 59), and 72.7% for acute liver failure (n = 22). The 5-year survival was 73.6% for the 209 children grafted in 1984-1990 and 85% for the 206 grafted in 1991-1996. Scarcity of size-matched donors led to the development of innovative techniques: 174 children who electively received a reduced liver as a first graft in our center had a 5-year survival of 76% while 168 who received a full-size graft had a survival of 85% (NS). Results of the European Split Liver Registry showed 6-month graft survival similar to results obtained with full-size grafts collected by the European Liver Transplant Registry. Extensive use of these techniques allowed the mortality while waiting to be reduced from 16.5% in 1984-1990 to 10% in 1991-1992. It rose again to 17% in 1993, leading the authors to develop a program of living related liver transplantation (LRLT). The legal and ethical aspects are analyzed. Between July 1993 and October 1997, the authors performed 53 LRLTs with 90% survival. In elective cases, a detailed analysis was made of the 45 children listed for LRLT between July 1993 and March 1997 and the 79 registered on the cadaveric waiting list during the same period. Mortality while waiting was 2% and 14.5% for the LRLT and cadaveric lists, respectively. The retransplantation rate was 4.6% and 16.1% for LRLT and cadaveric transplants, respectively. Overall post-transplant survival was 88% and 82% for children who received a LRLT or a cadaveric graft, respectively. Overall survival from the date of registration was 86% and 70% (P < 0.05) for LRLT or cadaveric LT respectively. The 2-year post-transplant survival in children less than 1 year of age at transplantation was 88.8% and 80. 3% with a LRLT or cadaveric graft, respectively; patient survival after 3 months post-transplant was 95.8% and 91.9% for stable children waiting at home, 93.7% and 93.7% in children hospitalized for complications of their disease, and 89.5% and 77.7% for children hospitalized in an intensive care unit at the time of transplantation for children who received a LRLT or cadaveric graft, respectively. It is concluded that LRLT seems to be justified for multidisciplinary teams having a large experience with reduced and split liver grafting.

The deltaccr5 mutation conferring protection against HIV-1 in Caucasian populations has a single and recent origin in Northeastern Europe.

The chemokine receptor CCR5 is encoded by the CMKBR5 gene located on the p21.3 region of human chromosome 3, and constitutes the major co-receptor for the macrophage-tropic strains of HIV-1. A mutant allele of the CCR5 gene, Delta ccr5 , was shown to provide to homozygotes with a strong resistance against infection by HIV. The frequency of the Delta ccr5 allele was investigated in 18 European populations. A North to South gradient was found, with the highest allele frequencies in Finnish and Mordvinian populations (16%), and the lowest in Sardinia (4%). Highly polymorphic microsatellites (IRI3.1, D3S4579 and IRI3.2, D3S4580 ) located respectively 11 kb upstream and 68 kb downstream of the CCR5 gene deletion were used to determine the haplotype of the chromosomes carrying the Delta ccr5 variant. A strong linkage disequilibrium was found between Delta ccr5 and specific alleles of the IRI3.1 and IRI3.2 microsatellites: >95% of the Delta ccr5 chromosomes carried the IRI3.1-0 allele, while 88% carried the IRI3.2-0 allele. These alleles were found respectively in only 2 or 1.5% of the chromosomes carrying a wild-type CCR5 gene. From these data, it was inferred that most, if not all Delta ccr5 alleles originate from a single mutation event, and that this mutation event probably took place a few thousand years ago in Northeastern Europe. The high frequency of the Delta ccr5 allele in Caucasian populations cannot be explained easily by random genetic drift, suggesting that a selection advantage is or has been associated with homo- or heterozygous carriers of the Delta ccr5 allele.

The second extracellular loop of CCR5 is the major determinant of ligand specificity.

The chemokine receptor CCR5 binds macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, and regulated on activation, normal T-cell expressed and secreted (RANTES), and constitutes the major co-receptor allowing infection of CD4(+) T lymphocytes, macrophages, and microglial cells by macrophage-tropic strains of human and simian immunodeficiency virus. CCR5 is most closely related to CCR2b, another chemokine receptor that responds to monocyte chemoattractant protein (MCP)-1, MCP-2, MCP-3, and MCP-4. We have investigated by mutagenesis the regions of CCR5 and CCR2b involved in the specificity of binding and functional response to their respective ligands. We demonstrate that the key region of CCR5 involved in its specific interaction with MIP-1alpha, MIP-1beta, and RANTES, and its subsequent activation, lies within the second extracellular loop (and possibly the adjacent transmembrane segments). Conversely, the NH2-terminal domain of CCR2b is responsible for the high affinity binding of MCP-1, but is not sufficient to confer activation of the intracellular cascades. Extracellular loops of the receptor, among which the second loop plays a prominent role, are necessary to achieve efficient signaling of the receptor. These data complement our previous mapping of CCR5 domains functionally involved in the fusion process with the human immunodeficiency virus envelope, and will help in the development of agents able to interfere with the early steps of viral infection.