Mitochondrial pro-apoptotic ARTS protein is lost in the majority of acute lymphoblastic leukemia patients

Acquired resistance towards apoptosis is the hallmark of most if not all types of cancer. We have previously identified and characterized ARTS, a broadly expressed protein localized to mitochondria. ARTS was initially shown to mediate TGF-beta induced apoptosis. Recently, we have found that high levels of ARTS induce apoptosis without additional pro-apoptotic stimuli. Further, ARTS promotes apoptosis in response to a wide variety of pro-apoptotic stimuli. Here, we report that the expression of ARTS is lost in all lymphoblasts of more than 70% of childhood acute lymphoblastic leukemia (ALL) patients. The loss of ARTS is specific, as the related non-apoptotic protein H5, bearing 83% identity to ARTS, is unaffected. During remission, ARTS expression is detected again in almost all patients. Two leukemic cell lines, ALL-1 and HL-60 lacking ARTS, were resistant to apoptotic induction by ara-C. Transfection of ARTS into these cells restored their ability to undergo apoptosis in response to this chemotherapeutic agent. We found that methylation process contributes to the loss of ARTS expression. We conclude that the loss of ARTS may provide a selective advantage for cells to escape apoptosis thereby contributing to their transformation to malignant lymphoblasts. We therefore propose that ARTS can function as a tumor suppressor protein in childhood ALL.     

Cyclin S: a new member of the cyclin family plays a role in long-term memory

Memory is thought to be subserved by structural and functional alteration in synaptic connectivity. But although neuronal plasticity requires gene expression, the identity of the proteins involved is largely unknown. Using the chick 1-day-old passive avoidance learning paradigm and differential display RNA fingerprinting, we identified 13 candidate genes which are upregulated in the intermediate medial hyperstriatum ventrale (IMHV), an area that has been correlated with the initial processing of memory formation. One of the induced genes is a new member of the cyclin family, with high homology to cyclin L (ania-6a). Analysis of the expression pattern of this gene after training revealed two time waves of induction: the first correlated with learning and initial memory process in the IMHV; the second correlated with memory consolidation, first in the IMHV, and then in the lobus paraolefactoris. There is a correlation between methylanthranilate (MeA) concentrations (the malaise substrate in the passive avoidance training procedure), the duration of memory and the expression level of cyclin S. While training chicks on low concentrations of MeA causes short-term memory and low expression level of cyclin S, high concentration of MeA induces long-term memory and high expression level of cyclin S in the IMHV. The role of cyclins in the regulation of neuronal-plasticity-related gene expression was overlooked, and it might serve as a key step in long-term memory formation.     

Phaeochromocytoma associated with a de novo VHL mutation as form fruste of von Hippel-Lindau disease

 Phaeochromocytomas usually occur sporadically but may be associated with dominant inherited cancer syndromes such as multiple endocrine neoplasia type 2 (MEN 2), von Hippel-Lindau disease (VHL) and type 1 neurofibromatosis. We report on a boy presenting at age 8 years with an isolated benign phaeochromocytoma of the left adrenal. Three years later a second adrenal phaeochromocytoma was diagnosed on the right side and removed. His family history was negative. Genetic analysis did not show a mutation in the MEN 2 susceptible proto-oncogene rearranged during transfection; however, we found a germline missense mutation in the VHL gene (nucleotide 695 G to A transversion) which has been described only twice before in the literature. Both parents had normal (wild type) VHL copies indicating that our patient had a de novo germline VHL mutation. Careful clinical evaluation of the patient at 18 years did not reveal any other manifestations of VHL disease. Conclusion Carriers of von Hippel-Lindau germline mutations can present with a form fruste of von Hippel-Lindau disease presenting initially with unilateral phaeo-chromocytoma and therefore mutation analysis should be carried out. Received: 21 June 2000 and in revised form: 18 February 2001 / Accepted: 20 February 2001     

Flow-controlled fluoroscopic angiography for the assessment of vascular integrity in bioengineered kidneys

Perfusion decellularization has been proposed as a promising method for generating nonimmunogenic organs from allogeneic or xenogeneic donors. Several imaging modalities have been used to assess vascular integrity in bioengineered organs with no consistency in the methodology used. Here, we studied the use of fluoroscopic angiography performed under controlled flow conditions for vascular integrity assessment in bioengineered kidneys. Porcine kidneys underwent ex vivo angiography before and after perfusion decellularization. Arterial and venous patencies were defined as visualization of contrast medium (CM) in distal capillaries and renal vein, respectively. Changes in vascular permeability were visualized and quantified. No differences in patency were detected in decellularized kidneys compared with native kidneys. However, focal parenchymal opacities and significant delay in CM clearance were detected in decellularized kidneys, indicating increased permeability. Biopsy-induced leakage was visualized in both groups, with digital subtraction angiography revealing minimal CM leakage earlier than nonsubtracted fluoroscopy. In summary, quantitative assessment of vascular permeability should be coupled with patency when studying the effect of perfusion decellularization on kidney vasculature. Flow-controlled angiography should be considered as the method of choice for vascular assessment in bioengineered kidneys. Adopting this methodology for organs premodified ex vivo under normothermic machine perfusion settings is also suggested.     

Protein-loss of SWI/SNF-complex core subunits influences prognosis dependent on histological subtypes of intra- and extrahepatic cholangiocarcinoma

Cholangiocarcinoma (CCA) is an aggressive malignancy with a 5-year-survival rate of <10%, mainly due to diagnosis in advanced stages and limited therapeutic options in case of progressive disease. Recently, evidence has indicated that alterations in the SWI/SNF-complex (SWI/SNF) may have an important role in the tumorigenesis of CCA. SWI/SNF-related chromatin remodeling has been reported to be crucial for differentiation and tumor suppression, and loss-of-function mutations of SWI/SNF are present in 20% of human malignancies; however, at present, little is known about its relevance in CCA. In the present study, a cohort of 52 patients with the diagnosis of primary CCA was retrospectively collected. All patients underwent surgery with curative intent. Tissue microarray analysis was performed on each tumor for immunohistochemical loss-of-protein analysis of the SWI/SNF core subunits ARID1A, INI-1, BRG1, PBRM-1 and BRM, corresponding to the following CCA subtypes: Extrahepatic CCA (ECCA), small duct or large duct intrahepatic CCA (ICCA). Kaplan-Meier analysis was used to determine survival distribution and survival differences were evaluated by log-rank test. In total, 14 of 52 patients (~35%) exhibited protein-loss of any tested SWI/SNF core subunit. Notably, 17% of patients exhibited a loss of ARID1a; this was the protein loss with the highest frequency. Patients with small and large duct ICCA with protein-loss of any tested SWI/SNF subunit exhibited significantly worse survival compared with the wild-type cohort with proficient protein expression (P=0.013 and P=0.002), whereas no significant survival difference was detected for patients with ECCA. SWI/SNF and its core subunits may be considered promising predictive and therapeutic targets, and require further investigation in patients with CCA.     

A longitudinal study of trends in keratitis in Australia

PURPOSE: To analyze the changes in risk factors, corneal culture results, antibiotic resistance, treatment, and clinical outcomes of patients with keratitis presenting to a major public hospital in Australia over a 5-year period. METHODS: A retrospective audit of all patients who had a corneal scraping between October 1999 and September 2004 at the Princess Alexandra Hospital. Clinical information was gathered from medical records and smear and culture results from the local microbiology database. The trends over time in patient demographics, keratitis risk factors, corneal culture results, antibiotic resistance, treatment, and clinical outcomes were analyzed by using linear regression. By using a moving average, we analyzed differences in the rate of culture of each causative organism for each month of the year with linear regression from the month of highest presentation. The mean of maximum temperatures on the days of presentation between different groups of organisms was compared. RESULTS: The proportion of patients presenting with keratitis related to contact lens wear increased significantly (12%-29%; P = 0.04) and with keratitis related to ocular surgery decreased significantly (18%-8%; P = 0.009) through the study. Antibiotic resistance of cultured bacteria to cephalothin increased significantly (2%-12%; P = 0.02), whereas resistance to ciprofloxacin and gentamicin remained at a low level throughout the study. There was significant variation in the monthly recovery of Pseudomonas aeruginosa (P = 0.04) and fungi (P = 0.02), which were cultured more frequently in summer months, whereas Streptococcus pneumoniae (P = 0.04) was more common in winter months than in other times of the year. Treatment with fluoroquinolones increased significantly (14%-40%; P = 0.002) through the study, and the rate of good outcomes also increased significantly (42%-72%; P = 0.02). CONCLUSIONS: In this series, keratitis related to contact lens wear became more frequent, whereas keratitis related to prior ocular surgery became less frequent. Different organism groups showed significant seasonal variations in their presentation, and bacterial resistance to cephalothin increased significantly.