Association study of a SNAP‐25 microsatellite and attention deficit hyperactivity disorder

Several lines of evidence implicate synaptosomal‐associated protein of 25 kDa (SNAP‐25) in the etiology of attention deficit hyperactivity disorder (ADHD). Most notably, the coloboma mouse mutant, considered to be a good animal model of hyperactivity, has a deletion spanning this gene. Introducing a SNAP‐25 transgene into these animals alleviates hyperlocomotion. We have identified a novel microsatellite repeat in SNAP‐25 located between the 5′UTR and the first coding exon, and tested for association with ADHD. Case‐control analyses suggest there may be a role of this polymorphism in ADHD, with one allele over‐represented in controls and another over‐represented in probands. Within‐family tests of linkage and association confirmed these findings. Further work is needed to ascertain the role of SNAP‐25 in ADHD and assess the functional significance of this polymorphism. © 2002 Wiley‐Liss, Inc.     

The intermediate filament complement of the spectrum of nerve sheath neoplasms

The intermediate filament complement of the spectrum of nerve sheath neoplasms including 12 typical benign schwannomas, 1 ancient schwannoma, 2 cellular schwannomas, 6 neurofibromas and 4 malignant schwannomas was investigated by immunofluorescence microscopy, two dimensional electrophoresis, and immunoblot analysis. Studies were performed on freshly frozen tumor tissue samples; a broad spectrum of antibodies against all classes of intermediate filaments was utilized. Samples were also studied by electron microscopy, and immunohistochemically for S-100 protein and desmoplakins. By immunofluorescence microscopy, all nerve sheath neoplasms revealed intense positivity for vimentin throughout the cytoplasm while 2 benign schwannomas displayed co-expression of vimentin and glial filament proteins. Two-dimensional gel electrophoresis and immunoblot analysis confirmed the presence of vimentin and showed that it was the predominant protein in all tumors. Electrophoretic analysis of the 2 benign schwannomas that immunostained for glial filament proteins confirmed the presence of this protein which was shown to comigrate with a known human control sample. Neither immunofluorescence microscopy nor biochemical analyses revealed cytokeratin polypeptides, neurofilament proteins, desmin, or desmoplakin in any of the tumors. We conclude that while vimentin is the predominant intermediate filament expressed by the entire spectrum of nerve sheath neoplasms, at least occasional benign schwannomas are capable of co-expressing glial filament proteins. It remains to be determined whether the subgroup of nerve sheath neoplasms that co-expresses vimentin and glial filament proteins is otherwise distinguishable from their more frequent counterparts that express vimentin exclusively.     

Chicken recombinant antibodies against infectious bursal disease virus are able to form antibody-virus immune complex.

Virus particles exposed to specific anti-virus antibodies result in the formation of immune complexes (Icx). Recent vaccination strategies have employed this feature, and an infectious bursal disease virus (IBDV) vaccine based on Icx has been released and is expected to replace conventional IBDV vaccines. We evaluated whether chicken recombinant antibodies (rAb) specific for IBDV, rather than conventional chicken anti-IBDV sera, could be used to generate Icx. Out of 14 rAb expressed as soluble single-chain variable fragments (scFv), nine were able to completely neutralize Bursavac, a live IBDV vaccine, when tested in ovo. When these rAb were mixed with IBDV and inoculated into either 18-day-old embryos, or 1-day-old or 2-week-old specific pathogen free chicks, a rAb.IBDV complex was formed. These Icx were similar to those produced by polyclonal chick anti-IBDV sera and IBDV. Following inoculation of the rAb.IBDV complex, the virus was rendered non-infectious for 5 to 7 days. After this time virus was released from the Icx, resulting in infection of the inoculated chicks and subsequent induction of an immune response and protection against virulent IBDV challenge. The results indicated that genetically derived antibodies can replace polyclonal sera in the formulation of Icx vaccines.     

Comparative analysis of the NS 1 gene sequences of dengue-1 viruses prototype Hawaii strain and Thai isolate TH-Sman,and determination of the intratypic variation of NS 1 protein among dengue-1 viruses

Summary In view of a previous report on significant antigenic and biophysical differences between the purified soluble complement-fixing antigens of dengue-1 virus strains Hawaii and TH-Sman, the NS 1 genes of both virus isolates were cloned, sequenced, and compared in an attempt to define the genetic basis for the observed differences. Sequence comparison revealed ten encoded amino acid differences between the NS 1 genes of both viruses. Three of these amino acid differences, which are associated with a change in charge distribution, are clustered within the major antigenic region previously defined by studies of recombinant dengue-1 NS 1 protein expressed inE. coli. In parallel, the NS 1 sequences of both Hawaii and TH-Sman isolates were also aligned and compared with two other published dengue-1 NS 1 protein sequences to determine the intratypic variation of dengue-1 NS 1 antigen. Pairwise comparisons between the encoded amino acid sequences revealed a variability of 1.1% to 3.1% difference in the NS 1 protein among dengue-1 strains, which is comparable to that reported for dengue-1 envelope protein (0.2% to 3.6% difference) but less than that of dengue-2 NS 1 protein (0.6% to 7.4% difference).     

Increased numbers of cytokeratin-positive interstitial reticulum cells (CIRC) in reactive,inflammatory and neoplastic lymphadenopathies: hyperplasia or induced expression?

A total of 291 enlarged lymph nodes showing a range of reactive-inflammatory processes, primary and metastatic neoplasms were studied to determine the distribution and immunoprofile of their cytokeratin-positive interstitial reticulum cells (CIRC) in comparison with normal nodes. In 258/291 nodes (89%), CIRC numbers were distinctly increased in the subcapsular, paracortical and, occasionally, in the medullary zones; often, these increased CIRC formed networks around follicles, sinuses and vessels. CIRC had comparatively small, irregularly shaped bodies and dendritic processes; occasionally, giant forms were noted. CIRC contained cytokeratins (CK) 8 and 18 but not 19, as shown by immunohistochemistry, and by gel electrophoresis with subsequent immunoblotting. They co-expressed vimentin consistently, alpha-smooth-muscle actin frequently, and desmin less frequently. They did not contain desmoplakins, Factor VIII, S-100, LCA, B and T lymphocyte- and macrophage-associated antigens, chromogranin A, synaptophysin or the A-80 glycoprotein. We found no clear correlation between the increased CIRC and given nodal disease processes. However, CIRC were most abundant in nodes free of but draining malignant tumours; bizarre CIRC assemblies were noted in HIV lymphadenopathy. CIRC appear to represent a subset of the so-called fibroblastic reticulum cells of lymph nodes. Their function remains undetermined; their increase in diverse lymphadenopathies suggests that they partake in nodal reactions to injury. It remains unclear whether the increase in CIRC relative number is due to proliferation or to CK gene induction processes but their presence and potential capability to undergo hyperplasia with dysplastic forms should alert pathologists to possible diagnostic pitfalls. In addition, we discuss that CIRC may undergo transformation and represent the cell of origin of certain CK-positive tumours restricted to lymph nodes.     

Chronic deciduitis in the placental basal plate: definition and interobserver reliability

This study tested whether concordance could be achieved for abnormal inflammation in the basal decidua of placental specimens among 6 pathologists experienced in placental pathology. Thirty microscope slides were evaluated by the pathologists for chronic deciduitis. They also scored the severity and extent of inflammation and the presence of plasma cells. No definition of chronic deciduitis was provided. Concordance (5/6 or 6/6 agreement) was achieved in 23 cases (76%). Spearman's rank correlation showed that the diagnosis of chronic deciduitis was almost identical to the assessment of the severity of the inflammation. A regression analysis showed that the perception of severity (and hence chronic deciduitis) was influenced by the other 2 variables, extent and plasma cells. The results were shared with the pathologists, and 25 cases (excluding those with previous 6/6 consensus) were reevaluated. Concordance was now achieved in the 83% of those remaining cases. Using a threshold based on the severity and the extent of lymphocytes, and the presence of plasma cells, pathologists are able to diagnose chronic deciduitis with sufficient concordance to be of value in clinical correlation studies.