Organ donation by Maastricht-III pediatric patients: Recommendations of the Groupe Francophone de Réanimation et Urgences Pédiatriques (GFRUP) and Association des Anesthésistes Réanimateurs Pédiatriques d'Expression Française (ADARPEF) Part I: Ethical considerations and family care.

The French Transplant Health Authority (Agence de la Biomédecine) has broadened its organ- and tissue-donation criteria to include pediatric patients whose death is defined by circulatory criteria and after the planned withdrawal of life-sustaining therapies (WLST) (Maastricht category III). A panel of pediatric experts convened to translate data in the international literature into recommendations for organ and tissue donation in this patient subgroup. The panel estimated that, among children aged 5 years or over with severe irreversible neurological injury (due to primary neurological injury or post-anoxic brain injury) and no progression to brain death, the number of potential donors, although small, deserves attention. The experts emphasized the importance of adhering strictly to the collegial procedure for deciding to withdraw life support. Once this decision is made, the available data should be used to evaluate whether the patient might be a potential donor, before suggesting organ donation to the parents. This suggestion should be reserved for parents who have unequivocally manifested their acceptance of WLST. The discussion with the parents should include both the pediatric intensive care unit (PICU) team under the responsibility of a senior physician and the hospital organ- and tissue-procurement team. All recommendations about family care during the end of life of a child in the PICU must be followed. The course and potential challenges of organ donation in Maastricht-III pediatric patients must be anticipated. The panel of experts recommended strict compliance with French recommendations (by the Groupe Francophone de Réanimation et Urgences Pédiatriques) about WLST and providing deep and continuous sedation until circulatory arrest. The experts identified the PICU as the best place to implement life-support discontinuation and emphasized the importance of returning the body to the PICU after organ donation. French law prohibits the transfer of these patients from one hospital to another. A description of the expert-panel recommendations regarding the organization and techniques appropriate for children who die after controlled circulatory arrest (Maastricht III) is published simultaneously in the current issue of this journal..

Organ donation by Maastricht-III pediatric patients: Recommendations of the Groupe Francophone de Réanimation et Urgences Pédiatriques (GFRUP) and Association des Anesthésistes Réanimateurs Pédiatriques d'Expression Française (ADARPEF). Part II: Specific organizational and technical considerations.

A panel of pediatric experts met to develop recommendations on the technical requirements specific to pediatric controlled donation after planned withdrawal of life-sustaining therapies (Maastricht category III). The panel recommends following the withdrawal of life-sustaining therapies protocol usually applied in each unit, which may or may not include immediate extubation. The organ retrieval process should be halted if death does not occur within 3 h of life-support discontinuation. Circulatory arrest is defined as loss of pulsatile arterial pressure and should be followed by a 5-min no-touch observation period. Death is declared based on a list of clinical criteria assessed by two senior physicians. The no-flow time should be no longer than 30, 45, and 90 min for the liver, kidneys, and lungs, respectively. At present, the panel does not recommend pediatric heart donation after death by circulatory arrest. The mean arterial pressure cutoff that defines the start of the functional warm ischemia (FWI) phase is 45 mmHg in patients older than 5 years and/or weighing more than 20 kg. The panel recommends normothermic regional perfusion in these patients. The FWI phase should not exceed 30 and 45 min for retrieving the pancreas and liver, respectively. There is no time limit to the FWI phase for the lungs and kidneys. The panel recommends routine sharing of experience with Maastricht-III donation among all healthcare institutions involved in order to ensure optimal outcome assessment and continuous discussion on the potential difficulties, notably those related to the management of normothermic regional perfusion in small children.

Cloning of a proopiomelanocortin cDNA from the pituitary gland of the sea bass (Dicentrarchus labrax) and assessment of mRNA expression in different tissues by means of real-time PCR.

Proopiomelanocortin (POMC) cDNA was cloned from sea bass (Dicentrarchus labrax) pituitary gland. A 743 nucleotide sequence was obtained coding for the following sequences flanked by sets of proteolytic cleavage sites: ACTH (Ser(88)-Met(127)), alpha-MSH (Ser(88)-Gly(102)), CLIP (Pro(106)-Met(127)), beta-LPH (Glu(131)-Gln(208)), gamma-LPH (Glu(131)-Ser(175)), beta-MSH (Asp(159)-Ser(175)), and beta-endorphin (Tyr(178)-Gln(208)). No region homologous to gamma-MSH/joining peptide (a tetrapod POMC feature) was found. Amino acid sequence identity was high with other teleostean species considered (tilapia: 73%) and lower with elasmobranchs (dogfish: 42%). However, the presumed biologically active peptides were highly conserved within all species considered: alpha-MSH (93-100%), ACTH (80-95%) and beta-endorphin (54-90%). Real-time PCR allowed us to quantify the expression of the POMC in different tIssues of the sea bass: pituitary gland, liver, gonad and head kidney. No significant POMC expression was found in the integument. In pituitary gland, gonads, head kidney and liver, POMC expression was respectively, 1.26x10(10), 2.67x10(5), 2.06x10(4) and 1.67x10(4) copies/ micro g mRNA.

High levels of the adhesion molecule CD44 on leukemic cells generate acute myeloid leukemia relapse after withdrawal of the initial transforming event.

Multiple genetic hits are detected in patients with acute myeloid leukemia (AML). To investigate this further, we developed a tetracycline-inducible mouse model of AML, in which the initial transforming event, overexpression of HOXA10, can be eliminated. Continuous overexpression of HOXA10 is required to generate AML in primary recipient mice, but is not essential for maintenance of the leukemia. Transplantation of AML to secondary recipients showed that in established leukemias, ∼80% of the leukemia-initiating cells (LICs) in bone marrow stopped proliferating upon withdrawal of HOXA10 overexpression. However, the population of LICs in primary recipients is heterogeneous, as ∼20% of the LICs induce leukemia in secondary recipients despite elimination of HOXA10-induced overexpression. Intrinsic genetic activation of several proto-oncogenes was observed in leukemic cells resistant to inactivation of the initial transformation event. Interestingly, high levels of the adhesion molecule CD44 on leukemic cells are essential to generate leukemia after removal of the primary event. This suggests that extrinsic niche-dependent factors are also involved in the host-dependent outgrowth of leukemias after withdrawal of HOXA10 overexpression event that initiates the leukemia.