Immunohistochemical expression of prion protein (PrPC) in the human forebrain during development.

The cellular prion protein (PrPC) is a ubiquitous protein whose expression in the adult brain occurs mainly in synapses. We used monoclonal antibodies to study fetal and perinatal PrPC expression in the human forebrain. Double immunofluorescence and confocal microscopy with GFAP, Iba1, MAP2, doublecortin, synaptophysin, and GAP-43 were used to localize PrPC. PrPC immunoreactivity was observed in axonal tracts and fascicles from the 11th week to the end of gestation. Synapses expressed PrPC at increasing levels throughout synaptogenesis. At midgestation, a few PrPC-labeled neurons were detected in the cortical anlage and numerous ameboid and intermediate microglial cells were PrPC-positive. In contrast, at the end of gestation, microglial PrPC expression decreased to almost nothing, whereas neuronal PrPC expression increased, most notably in ischemic areas. In adults, PrPC immunoreactivity was restricted to the synaptic neuropil of the gray matter. At all ages, choroid plexus, ependymal, and endothelial cells were labeled, whereas astrocytes were only occasionally immunoreactive. In conclusion, the early expression of PrPC in the axonal field may suggest a specific role for this molecule in axonal growth during development. Moreover, PrPC may play a role in early microglial cell development.

A rare case of leiomyosarcoma arising from a femoral vein tributary: a case report.

Primary vascular tumours are very rare. Most cases are leiomyosarcomas usually arising from large veins such as the inferior vena cava. Involvement of major veins in the limbs is uncommon and of small veins or tributaries extremely uncommon. We report a case of leiomyosarcoma originating from a tributary of the femoral vein in a 55-year-old woman.

Pleiotropic effects of CEP290 (NPHP6) mutations extend to Meckel syndrome.

Meckel syndrome (MKS) is a rare autosomal recessive lethal condition characterized by central nervous system malformations, polydactyly, multicystic kidney dysplasia, and ductal changes of the liver. Three loci have been mapped (MKS1-MKS3), and two genes have been identified (MKS1/FLJ20345 and MKS3/TMEM67), whereas the gene at the MKS2 locus remains unknown. To identify new MKS loci, a genomewide linkage scan was performed using 10-cM-resolution microsatellite markers in eight families. The highest heterogeneity LOD score was obtained for chromosome 12, in an interval containing CEP290, a gene recently identified as causative of Joubert syndrome (JS) and isolated Leber congenital amaurosis. In view of our recent findings of allelism, at the MKS3 locus, between these two disorders, CEP290 was considered a candidate, and homozygous or compound heterozygous truncating mutations were identified in four families. Sequencing of additional cases identified CEP290 mutations in two fetuses with MKS and in four families presenting a cerebro-reno-digital syndrome, with a phenotype overlapping MKS and JS, further demonstrating that MKS and JS can be variable expressions of the same ciliopathy. These data identify a fourth locus for MKS (MKS4) and the CEP290 gene as responsible for MKS.

Prognostic value of p53 overexpression in T1G3 bladder tumors treated with bacillus Calmette-Guérin therapy.

OBJECTIVES: To evaluate the correlation between the overexpression of mutant protein p53 and disease recurrence and progression in patients treated with bacillus Calmette-Guérin (BCG) intravesical therapy for T1G3 bladder cancer. METHODS: We analyzed the outcome of 29 consecutive patients treated for T1G3 bladder tumor with transurethral resection. Patients previously treated for a bladder tumor, those who underwent incomplete resection, and those in whom no assessment of the muscle cell layer was possible were excluded from the study. p53 overexpression was determined using monoclonal p53-DO7 antibody, with a 20% cutoff for definition of positivity. After the initial transurethral resection, all patients were treated with Pasteur BCG (75 mg in 50 mL saline), weekly for 6 weeks. The correlation between p53 overexpression and disease recurrence and progression was assessed by the Fisher exact test. RESULTS: The median follow-up was 36.7 months (range 1 to 108). Of the 29 patients, 18 (62.1%) were p53 positive and 11 (37.9%) were p53 negative. Both groups were similar according to age, tumoral substage (T1a/T1b), association with carcinoma in situ, multifocality, and length of follow-up. The recurrence rate was 54.4% in the p53-negative group versus 38.9% in the p53-positive group (P = 0.47). The progression rate was 18.2% in the p53-negative group versus 33.3% in the p53-positive group (P = 0.67). CONCLUSIONS: These findings suggest that overexpression of p53, as determined immunohistochemically, has no predictive value for recurrence and progression in T1G3 bladder cancers treated with intravesical BCG.

Relationship between vascular development and vascular differentiation during liver organogenesis in humans.

BACKGROUNDS/AIMS: The complex vascular architecture characteristic of the normal adult liver is progressively acquired during the fetal life. In this study, we aimed to evaluate the relationship between angiogenesis and vascular differentiation during liver organogenesis. METHODS: We studied, in 51 fetuses of different gestational ages, the expression of markers of endothelial cell differentiation, integrins, pro- and anti-angiogenic extracellular matrix components, vascular endothelial growth factor (VEGF) and its receptors. RESULTS: Three main stages in the development of the vascular architecture of the liver were identified: (a) from 5 to 10 gestation weeks (GW), no evidence of de novo angiogenesis was detected; the vessels present in the liver primordium were the precursors of portal veins and sinusoids, deriving from preexisting vessels; (b) from 10 to 25 GW, angiogenesis and vasculogenesis resulted in the development of, respectively, arteries and intra-portal capillaries, while portal veins and hepatic sinusoids followed a differentiation process; (c) after 25 GW, little changes were detected in the various vascular compartments. The maximal expression of VEGF and its receptors was from 5 to 25 GW. CONCLUSIONS: The development of the hepatic vascular architecture is a multistep process combining angiogenesis, vasculogenesis and vascular differentiation, regulated by specific growth and differentiation factors including VEGF.