Selective haploinsufficiency of longer isoforms of PTCH1 protein can cause nevoid basal cell carcinoma syndrome

Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disorder characterized by developmental defects and tumorigenesis. The gene responsible for NBCCS is PTCH1. The PTCH1 gene has five alternatively used first exons resulting in the translation of three isoforms of the PTCH1 protein; that is, PTCHL, PTCHM and PTCHS. However, the biological significance of each isoform is unclear. Here we show an individual with NBCCS carrying a nonsense mutation in PTCH1 exon2, c.387G>A (p.W129X). As the mutation lay upstream of the ATG codon used for PTCHS translation, the mutant allele still expressed RNA isoforms that encode PTCHS. These results clearly demonstrate that a selective haploinsufficiency of longer isoforms of the PTCH1 protein, PTCHL and PTCHM, but not PTCHS is sufficient to cause NBCCS. Although mice selectively deficient in PTCHS isoforms are currently unavailable, this study sheds light on the complex in vivo roles of PTCH1 isoforms.     

Germinal center B-cell-like diffuse large B-cell lymphoma of the duodenum is associated with t(14;18) translocation

Diffuse large B-cell lymphoma (DLBCL) rarely involves the duodenum, and its clinicopathological characteristics have not been well elucidated. We performed clinicopathological examinations and identified 15 patients with duodenal DLBCL using 18 gastric or colonic DLBCL as a control. Eleven of the 15 patients (73%) were subclassified by immunohistochemical analysis according to the Choi algorithm as germinal center B-cell-like (GCB) type, whereas the 18 control gastric and colonic DLBCL were predominantly subclassified as activated B-cell-like (ABC) type. The classifications according to organ involvement were statistically significant (P= 0.011 and P= 0.035). Macroscopically, the GCB lesions were varied, while all ABC lesions were ulcerative. Fluorescence in situ hybridization analysis revealed a higher frequency of t(14;18) translocation in patients with duodenal DLBCL (3 of 13) as compared with non-duodenal gastrointestinal tract DLBCL (0 of 18), however, the difference was not significant (P = 0.064). Furthermore, the three patients with t(14;18) translocations were classified as GCB. In addition, overall survival of patients was statistically different between those with and without t(14;18) translocation (P= 0.040). In conclusion, duodenal DLBCL predominantly exhibits GCB-type tumors and the frequency of t(14;18) translocation appears to be higher in duodenal GCB-type DLBCL compared to non-duodenal tumors.     

A common Ile796Val polymorphism of the human SREBP cleavage-activating protein (SCAP) gene

We identified a new common amino acid polymorphism of isoleucine/valine at codon 796 in exon 16 of the gene for human sterol regulatory element binding protein (SREBP) cleavage-activating protein (SCAP), a central regulator of lipid synthesis and metabolism in animal cells. It can be detected as an MslI restriction fragment length polymorphism. The allelic frequencies were: isoleucine (A) allele, 0.57 and valine (G) allele, 0.43. This polymorphism may be useful for genetic studies of disorders affecting intracellular lipid metabolism and hyperlipidemia. Received: August 17, 1999 / Accepted: August 19, 1999     

Oral use of interferon-alpha delays the onset of insulin-dependent diabetes mellitus in nonobese diabetes mice.

Insulin-dependent diabetes mellitus (IDDM) in the nonobese diabetes (NOD) mouse model is thought to be an autoimmune CD4 Th1-like cell-mediated disease. We tested the efficacy of oral use of interferon-alpha (IFN-alpha) therapy on IDDM in NOD mice. Using urine and blood sugar levels as indicators of IDDM, oral administration of murine IFN-alpha (100 IU/body) to NOD mice significantly delayed the onset of symptomatic diabetes. However, oral use of IFN-alpha did not prevent diabetic NOD mice from losing weight once NOD mice were symptomatic, suggesting that orally administered IFN-alpha is a prophylactic rather than therapeutic approach to the management of IDDM.     

Mitral Regurgitation Associated with Mitral Annular Dilation in Patients with Lone Atrial Fibrillation: An Echocardiographic Study

Background: Whether and how lone atrial fibrillation (AF) is associated with functional mitral regurgitation (MR) remain unclear. Method: We studied 12 lone AF patients without left ventricular (LV) dysfunction and/or dilatation, who underwent mitral valve annuloplasty for functional mitral regurgitation (MR). Ten lone AF patients without MR served as controls. Results: Lone AF Patients with MR had a greater mitral valve annular area and left atrial area than those without MR. There were no differences in LV volumes or LV ejection fraction. Conclusions: Therefore, we concluded that left atrial dilation and corresponding mitral annular dilation may cause MR in lone AF patients without LV dysfunction and/or dilatation.     

Development of oligomeric prion‐protein aggregates in a mouse model of prion disease

In prion diseases the normal cellular isoform of prion protein (PrP), denoted PrP^C, is converted into an abnormal, pathogenic isoform of PrP (PrP^Sc). Diagnostic tools for prion diseases are conventionally based on the detection of protease‐resistant PrP (PrP^res) after proteinase K digestion. However, recent studies have revealed that protease‐sensitive abnormal PrP (sPrP^Sc) also exists in significant amounts in brains suffering from prion diseases. Here, we designed a simplified size‐exclusion gel chromatography assay, using disposable spin columns to examine PrP aggregates in the course of the disease, without proteinase K digestion. Brain homogenates of NZW mice, inoculated intracranially with Fukuoka‐1 strain, and which died at around 120 days post‐inoculation, were assayed by this gel‐fractionation method and eluted PrP molecules in each fraction were detected by western blot analysis. Oligomeric PrP molecules were well separated from monomers, as predicted. A conventional protease‐digestion assay was also performed to detect PrP^res and revealed that the ratio of PrP^res to total PrP increased drastically from 105 days. However, the increase of PrP oligomers became significant from 90 days. These PrP oligomers in the early disease stage would, therefore, be sPrP^Sc molecules that might affect the disease pathology, such as spongiform change and abnormal PrP deposition. We also observed that the resistance of PrP oligomers to proteinase K and insolubility in phosphotungstic acid precipitation increased with disease progression, which suggests that PrP oligomers are not clearly distinguished from cellular PrP or PrP^res but may overlap in a continuous spectrum. Our study casts light on the ambiguity of the definition of PrP^Sc and indicates that the abnormality of PrP molecules should be determined from various perspectives, more than protease resistance. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Hypertrophic pachymeningitis as a result of a retropharyngeal inflammatory pseudotumor: case report

OBJECTIVE AND IMPORTANCE: An extremely rare case of a patient with hypertrophic pachymeningitis that resulted from an inflammatory pseudotumor of retropharynx is described. CLINICAL PRESENTATION: A 59-year-old man with a 9-year history of retropharyngeal inflammatory pseudotumor sought care for severe headache and multiple cranial nerve palsies. Magnetic resonance imaging and computed tomographic scans revealed pachymeningeal enhancement and obstructive hydrocephalus attributable to marked dural thickening around the foramen magnum. INTERVENTION: Decompression of the foramen magnum, C1 laminectomy, and meningeal biopsy were performed. The histological examination of the biopsy specimen revealed chronic inflammatory infiltrate in the hypertrophic dura mater. Corticosteroid pulse therapy was subsequently completed. Clinical and neuroradiological findings improved remarkably. CONCLUSION: A new case of hypertrophic pachymeningitis as a result of a retropharyngeal inflammatory pseudotumor is presented. We review and discuss the clinical features and the pathogenic mechanisms of hypertrophic pachymeningitis.     

The natural history and significance of radiolucent lines at a cemented femoral interface

We studied 185 total hip replacements and related the identification of radiolucent lines (RLLs) at two years to the later development of lytic lesions and loosening. Linear polyethylene wear was also measured. RLLs appeared in 34 hips at a mean of 2.0 years after operation, and lytic lesions in ten hips at 5.7 years. Of 151 THRs without RLLs there was neither rapid migration nor loosening and only one developed a possible lytic lesion. Of 23 hips with non-progressive RLLs there was neither rapid migration nor loosening, but six developed a lytic lesion. By contrast, 11 THRs with progressive RLLs migrated rapidly and seven developed a lytic lesion. Six THRs with progressive RLLs failed. The wear rates were the same in all groups, although limited numbers were available for study. If the surgeon achieves secure initial fixation as shown by slow or no migration and no RLLs during the first two years, it is likely that no lytic lesions will develop by five years or aseptic loosening by ten years. If an imperfect, but adequate, interface is achieved, as shown by slow migration and non-progressive RLLs lytic lesions adjacent to the RLLs may develop by five years, but aseptic loosening will be unlikely at ten. Insecure initial fixation, as shown by more rapid migration and progressive RLLs at two years, is likely to lead to the formation of lytic lesions at five years and loosening at ten. The outcome after THR is therefore determined at the initial operation and may be predicted at two years. The presence of lytic lesions reflects soft tissue at the interface as shown by the RLLs which accompany and promote loosening but, in our study, did not cause it.