Discrimination of face identities and expressions in children with autism: Same or different?

Abstract. Autism is a pervasive developmental disorder (PDD) characterized by the association of communication and socialization impairments, and by repetitive stereotyped behaviours. The Minnesota Test of Affective Processing (MNTAP) was used to investigate the discrimination of face identities and face expressions by autistic children. Young children in the 6- to 10-year-old age range suffering from PDD were compared to paired normal children. When the expressions on faces remained neutral, autistic patients had more difficulty in distinguishing different faces than in matching the same facial identities in face pairs: they perceived different faces as being identical. However, recognition errors disappeared when expressions were changed together with face identity. When autistic children were asked to distinguish expressions, they discriminated better identity than difference, just as normal children do. Analysis of face and expression discrimination in terms of identity and difference is a novel approach for the understanding of the clinical features of autism. Autistic children seek sameness and use an atypical strategy to analyse human faces and expressions.     

Variable phenotype related to a novel PAX 6 mutation (IVS4+5G>C) in a family presenting congenital nystagmus and foveal hypoplasia

PURPOSE: Several ocular defects have been identified as a consequence of the PAX6 gene mutations. With regard to the implication of this gene in unusual phenotypes, we report a family presenting with congenital nystagmus, foveal hypoplasia, and iris hypoplasia or atypical coloboma. DESIGN: Observational case report. METHODS: The entire transcribed region of the PAX6 gene was submitted to mutation search at the DNA and mRNA levels in five affected members of a French family in test with 82 normal subjects. RESULTS: A novel heterozygous PAX6 gene splice mutation (IVS4 + 5G>C) was identified. The mutation is located in IVS4 within the consensus donor splice site. A mutant mRNA lacking exon 4 as the sole defect was evidenced. The resultant protein was predicted to contain a cryptic ATG initiation codon in exon 3 and a slightly altered paired-domain in an open reading frame extended by 13 amino acids. CONCLUSIONS: The association of anterior segment anomalies and foveal hypoplasia with one of the slightest alterations of the PAX6 protein described to date confirms the association of variant phenotypes with hypomorphic alleles. Mutation screening of the PAX6 gene could be useful in elucidating the origin of complex ocular malformations.     

Exosomes and anti-tumour immunotherapy

Exosomes are 60 to 90 nm membrane vesicles originating from late endosomes and secreted from most hematopoietic and epithelial cells in vitro. B cell derived-exosome antigenicity was first reported in 1996 in MHC class II restricted CD4+ T lymphocytes. In 1998, we reported that dendritic cell derived-exosomes are immunogenic in mice leading to tumor rejection. These findings have renewed the interest in exosomes. The current challenge consists in understanding the mechanisms and the physiological relevance of exosomes that could contribute to the design of the optimal exosome based-vaccination. Here, we will focus on the biological features pertaining to dendritic cell- and tumor cell derived-exosomes and will discuss their potential clinical implementation.     

Neurofibrillary degeneration of the Alzheimer-type: an alternate pathway to neuronal apoptosis?

Neuronal death is a process which may be either physiological or pathological. Apoptosis and necrosis are two of these processes which are particularly studied. However, in neurodegenerative disorders, some neurons escape to these types of death and "agonize" in a process referred to as neurofibrillary degeneration. Neurofibrillary degeneration is characterized by the intraneuronal aggregation of abnormally phosphorylated microtubule-associated Tau proteins. A number of studies have reported a reactivation of the cell cycle in the neurofibrillary degeneration process. This reactivation of the cell cycle is reminiscent of the initiation of apoptosis in post-mitotic cells where G1/S markers including cyclin D1 and cdk4/6, are commonly found. However, in neurons exhibiting neurofibrillary degeneration, both G1/S and G2/M markers are found suggesting that they do not follow the classical apoptosis and an aberrant cell cycle occurs. This aberrant response leading to neurofibrillary degeneration may be triggered by the sequential combination of three partners: the complex Cdk5/p25 induces both apoptosis and the "abnormal mitotic Tau phosphorylation". These mitotic epitopes may allow for the nuclear depletion of Pin1. This latter may be responsible for escaping classical apoptosis in a subset of neurons. Since neurofibrillary degeneration is likely to be a third way to die, molecular mechanisms leading to changes in Tau phosphorylation including activation of kinases such as cdk5 or other regulators such as Pin1 could be important drug targets as they are possibly involved in early stages of neurodegeneration.     

Interobserver variation in the interpretation of abdominal radiographs

A total of 140 sets of abdominal radiographs were reviewed independently by four qualified diagnostic radiologists. The degree of interobserver agreement was determined by calculating kappa values for 19 commonly used radiographic signs and diagnoses. There was fair to excellent interobserver agreement for 11 signs and diagnoses and poor agreement for the remaining eight. The signs and diagnoses for which agreement is poor cannot be considered reliable and include particularly large bowel obstruction and nonspecific gas pattern.     

Effect of intersection spacing on MR image contrast and study time

The effects of section separation on image contrast and calculated T1 relaxation times were investigated in healthy volunteers and a phantom using an early commercial version magnetic resonance imaging system. The effects are explained qualitatively on the basis of side lobes of excitation occurring outside the selected section resulting in reduction of the time permitted for T1 relaxation. The options for dealing with imperfect section selection, including separation of the sections (i.e., leaving gaps) and nonsequential excitation, are illustrated and the trade-offs involved in each explained.     

Perforation of the inferior vena cava with aortic and vertebral penetration by a suprarenal Greenfield filter

Various complications have been reported after insertion of the Greenfield filter. This report describes an unusual complication after suprarenal placement of this filter: spreading of the filter struts, with perforation of the inferior vena cava, and penetration of the aorta and a vertebral body, followed by fracture of one of the struts.