A function of Fas-associated death domain protein in cell cycle progression localized to a single amino acid at its C-terminal region

FADD is an adaptor known to transmit apoptotic signals from members of the tumor necrosis factor receptor family. We show here that FADD has a domain implicated in cell proliferation. Mice bearing the Asp mutation in the serine 191 phosphorylation site are runted and anemic and display splenomegaly. Apoptosis is unimpaired in these mice, but they exhibit many immune developmental problems indicative of proliferative defects. Mutant FADD T cells are defective in cell cycle progression, suggesting that regulation of phosphorylation at serine 191 is essential for growth/proliferation. Remarkably, serine 191 is conserved among mammalian FADD proteins, but this C-terminal region is absent in lower organisms, suggesting that FADD acquired a domain during evolution, rendering it a "proliferation-apoptosis coupler" that balances cell proliferation and apoptosis.     

A novel missense mutation (I344K) in the SPG4gene in a Korean family with autosomal-dominant hereditary spastic paraplegia

 Hereditary spastic paraplegia (HSP) is a group of clinically and genetically heterogeneous neurodegenerative disorders characterized by slowly progressive spasticity and weakness of the lower extremities. Among eight loci linked with autosomal-dominant (AD)-HSP, the SPG4 locus on chromosome 2p22 accounts for about 40% of all patients. Recently, mutations in a new member of the AAA protein family, called spastin, have been identified as responsible for SPG4-linked AD-HSP. Here, we describe a novel missense mutation (c.1031T>A; I344K) in exon 7 of the SPG4 gene identified in a Korean family with typical clinical features of pure AD-HSP. The mutation affects the third amino acid of the highly conserved AAA cassette domain, which is the most fore part of the domain altered by a missense mutation reported so far. Clinical presentations of affected individuals carrying the I344K mutation were not different from those of pure AD-HSP with SPG4 mutations reported previously. However, it is noteworthy that neither urinary dysfunction nor involvement of upper extremities was noticed in this family. To our knowledge, this is the first report of genetically confirmed AD-HSP in Korea. Received: February 20, 2002 / Accepted: May 21, 2002     

Permeation of human ovarian tissue with cryoprotective agents in preparation for cryopreservation

The recent improvements in the treatment of cancer by chemo- and radiotherapy have led to a significant increase in the survival rates of patients with malignant disease, but at the expense of distressing side effects. One major problem, especially for younger patients, is that aggressive therapy destroys a significant proportion of the follicular population, which can result in either temporary or permanent infertility. Freeze-banking pieces of ovarian cortex prior to treatment is one strategy for preserving fecundity. When the patient is in remission, fertility could, theoretically, be restored by autografting the thawed tissue at the orthotopic site or by growing isolated follicles to maturity in vitro. Recent studies have found good follicular survival in frozen-thawed human ovarian tissue but to optimize the process an effective cryopreservation method needs to be developed. An essential part of such a technique is to permeate the tissue with a cryoprotectant to minimize ice formation and the extent of this equilibration is an important determinant of post-thaw cellular survival. In the current study, we have investigated the diffusion of four cryoprotective agents into human tissue at both 4 degrees C and 37 degrees C. We have also studied the effect of adding different concentrations of the non penetrating cryoprotective agent, sucrose, to the freezing media using the release of lactate dehydrogenase as a measure of its protective effect. At 4 degrees C propylene glycol and glycerol penetrated the tissue significantly slower than either ethylene glycol or dimethyl sulphoxide. At the higher temperature of 37 degrees C all four cryoprotectants penetrated at a faster rate, however concern about enhanced toxicity prevents the use of these conditions in practice. Thus, the results suggest that the best method of preparing tissue for freezing is exposure for 30 min to 1.5 M solutions of ethylene glycol or dimethyl sulphoxide at 4 degrees C; this achieved a mean tissue concentration that was almost 80% that of the bathing solution. We also report that the addition of low concentrations of sucrose to the freezing medium does not have a significant protective effect against freezing injury.      

Immunohistochemical labeling for the Dpc4 gene product is a specific marker for adenocarcinoma in biopsy specimens of the pancreas and bile duct.

We immunohistochemically labeled 72 biopsy specimens from the extrahepatic biliary tree and pancreas for Dpc4 protein and correlated expression with histologic diagnosis and patient follow-up. Specimens were classified histologically as follows: nonneoplastic, 35; neoplastic, 22; atypical, 15. Loss of expression of Dpc4 protein was identified in 12 specimens; 11 were histologically diagnostic of carcinoma. The 12th specimen was from a patient whose biopsy specimen initially was diagnosed as "atypical," but clinical follow-up revealed adenocarcinoma. Of the 12 atypical biopsy specimens with intact expression for Dpc4, follow-up later revealed that 10 were adenocarcinoma. Loss of expression of Dpc4 protein was never identified in a benign specimen. Immunohistochemical labeling for the Dpc4 gene product is a specific marker of carcinoma in biopsy specimens of the pancreas and extrahepatic bile ducts and is marginally helpful in classifying atypical specimens. The sensitivity for carcinoma is low. This latter finding is not unexpected, because the DPC4 tumor suppressor gene is inactivated in only about half of pancreatic and biliary malignant neoplasms. Importantly, loss of Dpc4 expression has been reported in in situ carcinomas, suggesting that loss of expression should not be equated with invasive carcinoma.     

Sequencing of the alpha-synuclein gene in a large series of cases of familial Parkinson's disease fails to reveal any further mutations. The European Consortium on Genetic Susceptibility in Parkinson's Disease (GSPD)

A mutation in exon 4 of the human alpha-synuclein gene was reported recently in four families with autosomal dominant Parkinson's disease (PD). In order to examine whether mutations in this exon or elsewhere in the gene are common in familial PD, all seven exons of the alpha- synuclein gene were amplified by PCR from index cases of 30 European and American Caucasian kindreds affected with autosomal dominant PD. Each product was sequenced directly and examined for mutations in the open reading frame. No mutations were found in any of the samples examined. We conclude that the A53T change described in the alpha- synuclein gene is a rare cause of PD or may even be a rare variant. Mutations in the regulatory or intronic regions of the gene were not excluded by this study.