Radioiodinated tracers for the evaluation of dopamine receptors in the neonatal rat brain after hypoxic-ischemic injury

In order to evaluate in vivo single-photon emission tomography (SPET) method of assessing cerebral function after hypoxic-ischemic injury in human neonates, we studied D₁ and D₂ dopamine receptors in a rat model. Seven-day-old rats underwent permanent unilateral common carotid ligation followed by exposure to 8% O₂. Two weeks later, in brains with no visible loss of hemispheric volume, striatal dopaminergic receptors were studied, with [¹²⁵I]TISCH and [1251]IBZM for the D₁ and D₂ dopamine receptors, respectively. Using [¹²⁵I]TISCH, we observed no modifications of D₁ receptors, but in contrast, ex vivo and in vitro autoradiographic experiments showed a 40% decrease in the striatal binding of [¹²⁵I]IBZM on both the ipsilateral and the contralateral side to the carotid ligation. These alterations were detected with IBZM, a D₂ dopamine receptor ligand usable for SPET imaging. Therefore, exploration of D₂ receptors by SPET in human neonates suffering from perinatal hypoxia-ischemia may be valuable for the diagnosis and follow-up of cerebral function damages. Correspondence to: D. Guilloteau     

Rashkind atrio-septostomy in incubators and neonatal intensive care units]

In 7 neonates with cyanotic heart disease, balloon atrial septostomy was performed in the neonatal intensive care unit under two-dimensional echocardiographic control. Trans-umbilical route was used with success in 6 neonates and percutaneous femoral vein in 1 neonate after failure of the trans-umbilical route. The mean transcutaneous oxygen saturation increase was 22%. No complications were observed. The average duration of the procedure was 25 minutes. Thus this technique is efficient, quick and easy to perform, allowing the procedure to be done under optimal environmental conditions in critically ill neonates.     

Le DRESS syndrome, une réaction d''hypersensibilité aux médicaments, qui reste mal connue des pédiatres

The DRESS syndrome (Rash with Eosinophilia and Systemic Symptoms) is a drug hypersensitivity reaction poorly known by paediatricians. It occurs within 1 to 8 weeks of treatment. Clinical features associate in variable patterns, fever, rash, lymphadenopathies, arthritis and potentially life-threatening damage (hepatitis, nephritis, pneumonitis), hyperleucocytosis and eosinophilia. This condition must be early recognized in order to immediately stop suspect drugs. A 6.5 year old girl had a febrile rash, hyperleucocytosis, lymph nodes and cytolitic hepatitis probably due to phenobarbital. Diagnosis of DRESS syndrome was performed only 13 days after the beginning of the eruption. Evolution was favorable but characterized by the recurrence of the febrile eruption with pleuritis. DRESS syndrome is a well described disease that occurs during treatment with a number drugs, particularly anti-epileptic drugs. Steroid therapy and immunoglobulins are proposed for treatment but have not been evaluated.     

Prevalence rates and psychosocial characteristics associated with depression in pregnancy and postpartum in Maltese women

BACKGROUND: Investigators have commented on the apparent high prevalence of psychiatric symptoms in pregnancy. In Malta there is lack of epidemiological data and therefore, the prevalence of depression during pregnancy and at 8 weeks postpartum among a community sample of Maltese women was carried out. METHOD: A random sample of 239 pregnant women were interviewed at booking using a detailed sociodemographic history, the revised version of the clinical interview schedule (CIS-R) and Maltese translation of the Edinburgh postnatal depression scale (EPDS). The CIS-R was again administered over the phone at 36 weeks and the EPDS sent by post. At 8 weeks postpartum, the CIS-R, modified version of the social maladjustment schedule and the EPDS were again administered to 95.8% of women. RESULTS: The point prevalence of depression meeting ICD-10 research criteria was 15.5% at booking, 11.1% in the third trimester and 8.7% postpartum of which only 3.9% had an onset since delivery. CONCLUSIONS: The low rate of new onset postpartum depression compared with other studies in our sample may be attributable to the social support available to women living in a cohesive Catholic island community. LIMITATION: The follow-up was limited to 8 weeks postpartum. No control group was used to compare the prevalence of depression in women who did not recently have a baby.     

INAUGURAL ARTICLE by a Recently Elected Academy Member:Clathrin mediates both internalization and vesicular release of triggered T cell receptor at the immunological synapse

Ligation of T cell receptor (TCR) to peptide–MHC (pMHC) complexes initiates signaling leading to T cell activation and TCR ubiquitination. Ubiquitinated TCR is then either internalized by the T cell or released toward the antigen-presenting cell (APC) in extracellular vesicles. How these distinct fates are orchestrated is unknown. Here, we show that clathrin is first recruited to TCR microclusters by HRS and STAM2 to initiate release of TCR in extracellular vesicles through clathrin- and ESCRT-mediated ectocytosis directly from the plasma membrane. Subsequently, EPN1 recruits clathrin to remaining TCR microclusters to enable trans-endocytosis of pMHC–TCR conjugates from the APC. With these results, we demonstrate how clathrin governs bidirectional membrane exchange at the immunological synapse through two topologically opposite processes coordinated by the sequential recruitment of ecto- and endocytic adaptors. This provides a scaffold for direct two-way communication between T cells and APCs.

The fundamental molecular interactions responsible for regulating the adaptive immune response occur within a nanoscale gap between T cells and antigen-presenting cells (APCs) termed the immunological synapse (IS). IS formation is induced upon T cell receptor (TCR) interactions with agonist peptide-Major Histocompatibility Complex (pMHC) on the surface of APCs (1, 2). This process can be recapitulated by antigen presentation on supported lipid bilayers (SLBs), a minimal system composed of a mobile lipid phase configured to present relevant ligands at physiological densities (3, 4). Such IS formation on SLBs allows for microscopic analysis of the receptor–ligand interactions and membrane trafficking events underlying the initiation and effector functions of the adaptive immune system.During activation, the components of the IS rearrange in the opposing lipid membranes to form a characteristic bull’s-eye pattern consisting of three primary domains (5, 6). The bull’s-eye itself is termed the central supramolecular activation cluster (cSMAC) and is dominated by TCR and its ligands in a synaptic cleft. This area is surrounded by an adhesive ring defined by Lymphocyte Function-associated Antigen-1 (LFA-1) on the T cell side associated with intercellular adhesion molecule-1 (ICAM-1) on the SLB termed the peripheral supramolecular activation cluster (pSMAC). The outer edge of the contact is defined by an F-actin–rich sensory compartment termed the distal supramolecular activation cluster (dSMAC). TCR engagement is initiated in microclusters that arise from filopodia in the dSMAC and retain protrusive activity even as they traffic through the pSMAC toward the cSMAC (7–11). This is accompanied by CD3 tyrosine phosphorylation, recruitment of Zeta-associated protein of 70 kDa (ZAP-70), and phosphorylation of Linker of Activated T cells (LAT) (12) and recruitment of SH2-domain-containing leukocyte protein of 76 kDa (SLP-76) (13). These then form condensates organized by LAT, traversing concentric actin networks en route to the cSMAC (14).Formation of the cSMAC by helper T cells has been shown to require recognition of ubiquitinated TCR by Tumor susceptibility gene 101 (TSG101), a component of the endosomal sorting complex required for transport (ESCRT) (15). Then, following TSG101-dependent TCR sorting, the ESCRT-associated ATPase VPS4 mediates scission of TCR loaded extracellular vesicles termed synaptic ectosomes, which bud directly from the plasma membrane into the synaptic cleft (16). This is mechanistically similar to formation of the intraluminal vesicles (ILVs) of multivesicular endosomes and budding of HIV virions from the plasma membrane (17, 18). Prior to action of TSG101, the ESCRT component Hepatocyte growth factor-regulated tyrosine kinase substrate (HRS) recognizes ubiquitinated cargo and recruits clathrin, which assembles into flat lattices to mediate recruitment of subsequent ESCRT machinery (19, 20). Clathrin- and HRS-positive vesicles have also been shown to polarize toward the IS during T cell activation, and they have been implicated in recruiting F-actin there (21). However, it is not known whether clathrin is involved in the formation of synaptic ectosomes.Clathrin is primarily known for its role in endocytosis, where it is recruited to the plasma membrane by adaptor proteins such as Epsin-1 (EPN1) and Adaptor Protein complex-2 (AP-2) (22, 23). Together, these proteins facilitate deformation and invagination of the membrane which is ultimately pinched off as a clathrin-coated endocytic vesicle (24) by the large GTPase dynamin (25–27). Previous reports have shown that this mechanism is engaged to internalize TCR during constitutive TCR recycling (28, 29) and to internalize nonactivated bystander TCR during T cell activation (30). It has also been shown that TCR triggering leads to phosphorylation of clathrin heavy chain (CHC), (31) and TCR has been observed in clathrin-coated pits following antibody activation (32). However, conflicting evidence has indicated that clathrin is not involved in internalization of triggered TCR in the Jurkat cell line (30, 33, 34). Hence, the role of clathrin in endocytosis of pMHC–TCR conjugates is yet to be established.Synaptic ectosomes are important for delivery of T cell help through CD40 ligand and additional signals (35). TCR endocytosis is required for postendocytic signaling and regulation of pMHC availability (36, 37). Therefore, it is critical to understand the balance between ectocytosis and endocytosis of the TCR. Here, we show that clathrin is pivotal during T cell activation through its essential role in two sequential processes. First, clathrin is essential for ESCRT-mediated release of TCR loaded synaptic ectosomes at the cSMAC. As the IS matures, there is a temporal switch from the clathrin-associated ESCRT components HRS and STAM2 to the endocytic clathrin adaptor EPN1. Remaining antigen-ligated TCRs are then internalized by clathrin-mediated trans-endocytosis.     

Melatonin modulates neonatal brain inflammation through endoplasmic reticulum stress,autophagy, and miR‐34a/silent information regulator 1 pathway

Maternal infection/inflammation represents one of the most important factors involved in the etiology of brain injury in newborns. We investigated the modulating effect of prenatal melatonin on the neonatal brain inflammation process resulting from maternal intraperitoneal (i.p.) lipopolysaccharide (LPS) injections. LPS (300 μg/kg) was administered to pregnant rats at gestational days 19 and 20. Melatonin (5 mg/kg) was administered i.p. at the same time as LPS. Melatonin counteracted the LPS sensitization to a second ibotenate‐induced excitotoxic insult performed on postnatal day (PND) 4. As melatonin succeeded in reducing microglial activation in neonatal brain at PND1, pathways previously implicated in brain inflammation regulation, such as endoplasmic reticulum (ER) stress, autophagy and silent information regulator 1 (SIRT1), a melatonin target, were assessed at the same time‐point in our experimental groups. Results showed that maternal LPS administrations resulted in an increase in CHOP and Hsp70 protein expression and eIF2α phosphorylation, indicative of activation of the unfolded protein response consequent to ER stress, and a slighter decrease in the autophagy process, determined by reduced lipidated LC3 and increased p62 expression. LPS‐induced inflammation also reduced brain SIRT1 expression and affected the expression of miR‐34a, miR146a, and miR‐126. All these effects were blocked by melatonin. Cleaved‐caspase‐3 apoptosis pathway did not seem to be implicated in the noxious effect of LPS on the PND1 brain. We conclude that melatonin is effective in reducing maternal LPS‐induced neonatal inflammation and related brain injury. Its role as a prophylactic/therapeutic drug deserves to be investigated by clinical studies.     

Post‐transplantation cyclophosphamide versus conventional graft‐versus‐host disease prophylaxis in mismatched unrelated donor haematopoietic cell transplantation

Post‐transplantation cyclophosphamide (PTCy) is an effective strategy to prevent graft‐versus‐host disease (GVHD) after haploidentical haematopoietic cell transplantation (HCT). We determined the efficacy of PTCy‐based GVHD prophylaxis in human leucocyte antigen (HLA)‐mismatched unrelated donor (MMUD) HCT. We analysed 113 adult patients with high‐risk haematological malignancies who underwent one‐antigen MMUD transplantation between 2009 and 2013. Of these, 41 patients received PTCy, tacrolimus and mycophenolate mofetil (MMF) for GVHD prophylaxis; 72 patients received conventional prophylaxis with anti‐thymocyte globulin, tacrolimus and methotrexate. Graft source was primarily bone marrow (83% PTCy vs. 63% conventional group). Incidence of grade II–IV (37% vs. 36%, P = 0·8) and grade III–IV (17% vs. 12%, P = 0·5) acute GVHD was similar at day 100. However, the incidence of grade II‐IV acute GVHD by day 30 was significantly lower in the PTCy group (0% vs. 15%, P = 0·01). Median time to neutrophil (18 days vs. 12 days, P < 0·001) and platelet (25·5 days vs. 18 days, P = 0·05) engraftment was prolonged in PTCy group. Rates of graft failure, chronic GVHD, 2‐year non‐relapse mortality, relapse, progression‐free survival or overall survival were similar. Our results demonstrate that PTCy, tacrolimus and MMF for GVHD prophylaxis is safe and produced similar results as conventional prophylaxis in patients with one antigen HLA‐MMUD HCT.     

Locus of control moderates the relationship between headache pain and depression

The aim of the current study was to triangulate qualitative and quantitative data in order to examine in greater detail the relationship between self-reported headache pain severity, depression and coping styles. Psychosocial scales, headache characteristic scales and in-depth interviews were administered to 71 adults with the diagnosis of primary headache. Regression analyses with the scales showed that greater self-reported headache pain severity was associated with higher levels of depression. A high internal locus of control weakened the relationship between the headache severity and depression variables. The qualitative data supported the relationship between pain severity and internal locus of control and, in addition, revealed that perceived efficacy of pharmacologic intervention might be a related factor. The results suggested that stronger coping skills might reduce depression among headache sufferers.