Comparison of global DNA methylation profiles in replicative versus premature senescence

DNA methylation is considered to play an essential role in cellular senescence. To uncover the mechanism underlying cellular senescence, we established the model of premature senescence induced by hydrogen peroxide (H(2)O(2)) in human embryonic lung fibroblasts and investigated the changes of genome methylation, DNA methyltransferases (DNMTs) and DNA-binding domain proteins (MBDs) in comparison with those observed during normal replicative senescence. We found that premature senescence triggered by H(2)O(2) exhibited distinct morphological characteristics and proliferative capacity which were similar to those of replicative senescence. The genome methylation level decreased gradually during the premature as well as replicative senescence, which was associated with the reduction in the expression of DNMT1, reflecting global hypomethylation as a distinct feature of senescent cells. The levels of DNMT3b and methyl-CpG binding protein 2 (MeCP2) increased in both mid-aged and replicative senescent cells, while DNMT3a and MBD2 were upregulated in the mid-aged cells. Only DNMT3b was elevated in the cells in the premature senescence persistence status. Additionally, the expression for DNMTs, MBD2 and MeCP2 was increased rapidly upon H(2)O(2) treatment. These results indicate that H(2)O(2)-induced premature senescence share some features of replicative senescence, such as basic biological characteristics and global hypomethylation while there are slight differences in the profile of methylation-associated enzyme expression. Oxidative damage may hence be a causative factor in epigenetic alteration partly responsible for cellular senescence.

[Study on expression regularity of XPV mRNA in L-02 hepatic cells induced by hydroquinone]

OBJECTIVE

To study the effect of hydroquinone (HQ) on expression of XPV mRNA in L-02 hepatic cells and its regularity, in order to explore the possible molecular mechanism of XPV in the process of the toxic effects of HQ to L-02 hepatic cells.

METHODS

Expression of XPV mRNA in L-02 hepatic cells treated at the dose of 40 micromol/L HQ for 6, 12, 24 and 48h in vitro and its expression in L-02 hepatic cells treated at the concentrations of 0, 5, 10, 20, 40, 80 and 160 micromol/L HQ for 24h was measured by real-time fluorescence quantitative PCR.

RESULTS

In the range of 0-24h, the expressions of XPV mRNA in L-02 hepatic cells in treated group (40 micromol/L) and control group increased with increase of time, and expressions of XPV reached the maximum levels at the times of 24h,and reduced the minimum levels at the times of 48h. At the time ranges of 6, 12, 24 and 48h,the expression levels of XPV mRNA in L-02 hepatic cells treated with HQ (40 micromol/L) were more higher than those of the control (0 micromol/L). The expression level of XPV mRNA in L-02 hepatic cells treated by HQ at the concentration of 0-80 micromol/L for 24h increased in a dose-dependent manner.Taken the expression level of the control group as 1, the relative expression levels in various treatment groups were added to 1.20, 2.02, 2.37, 2.67, 4.40 and 2.32 fold respectively. The expressions of XPV mRNA in the group treated with HQ (160 micromol/L) was reduced, but was higher than that of the control.

CONCLUSION

HQ could induce the expression of XPV at mRNA levels in a dose- and time-dependent manner, which indicated that XPV could involved in the response of L-02 hepatic cells of HQ.

Epigenetic silencing of O6-methylguanine DNA methyltransferase gene in NiS-transformed cells

Nickel (Ni) compounds are potent carcinogens and can induce malignant transformation of rodent and human cells. To uncover the molecular mechanisms of nickel sulfide (NiS)-induced cell transformation, we investigated epigenetic alterations in a set of DNA repair genes. The silencing of the O(6)-methylguanine DNA methyltransferase (MGMT) gene locus and upregulation of DNA methyltransferase 1 (DNMT1) expression was specifically detected in NiS-transformed human bronchial epithelial (16HBE) cells. In addition, we noted epigenetic alterations including DNA hypermethylation, reduced histone H4 acetylation and a decrease in the ratio of Lys-9 acetylated/methylated histone H3 at the MGMT CpG island in NiS-transformed 16HBE cells. Meanwhile, we identified concurrent binding of methyl-CpG-binding protein 2, methylated DNA-binding domain protein 2 and DNMT1 to the CpG island of the MGMT promoter, demonstrating that these components collaborate to maintain MGMT methylation in NiS-transformed cells. Moreover, depletion of DNMT1 by introduction of a small hairpin RNA construct into NiS-transformed cells resulted in a 30% inhibition of cell proliferation and led to increased MGMT gene expression by reversion of the epigenetic modifications at the MGMT promoter region. MGMT suppression and hypermethylation at the CpG island of the MGMT promoter occurred 6 days after NiS treatment, indicating that epigenetic modifications of MGMT might be an early event in tumorigenesis. Taken together, these observations demonstrate that epigenetic silencing of MGMT is associated with DNA hypermethylation, histone modifications and DNMT1 upregulation, which contribute to NiS-induced malignant transformation.

Induction of a cell-survival adaptive response in MRC-5 cells by hydroquinone

Although it is known that some cell types exhibit an adaptive response to low levels of cytotoxic agents, its molecular mechanism is still unclear and it has yet to be established whether this is a universal phenomenon that occurs in all cell types in response to exposure to every chemical. Hydroquinone is a synthetically produced as well as naturally occurring chemical. Human exposure to hydroquinone is predominantly through diet, cigarette smoke and occupational contact. Here, we asked whether exposure of human lung embryonic MRC-5 fibroblasts to low doses of hydroquinone leads to a cell-survival adaptive response. We further examined the possible mechanisms of an adaptive response using proteomics. We found that exposure of MRC-5 cells to low levels of hydroquinone resulted in adaptation to further exposure to lethal doses of hydroquinone at the cell-survival level, measured using the alamarBlue assay, lactate dehydrogenase leakage assay and Annexin V-FITC/PI staining. To determine the polypeptide products involved in the adaptive response, two-dimensional electrophoresis combined with mass spectrometry was performed. Twenty-three protein spots were significantly changed during the adaptive response. Among them, 21 protein spots were identified by peptide mass fingerprinting and/or peptide sequence analysis by MALDI-TOF-TOF. The identified proteins included proteins involved in energy metabolism, protein folding, redox regulation, cell structure and cell signaling. Our data suggest that the hydroquinone-induced adaptive response is a complex process involving in a modulation of diverse cellular functions, and that the redox regulation might be a common mechanism during the adaptive response.

Comparative proteomic analysis on human L-02 liver cells treated with varying concentrations of trichloroethylene

To determine the differential proteomic expressions in human L-02 liver cells induced by varying concentrations of trichloroethylene (TCE), comparative proteomic analysis was performed on human L-02 liver cells which were treated with varying concentrations of TCE. According to the result of MTT test, we designed four different groups, in which the cells were treated with 0 microM (control group), 3, 10 or 40 microM TCE for 24 h, respectively. Comparative analysis of approximately 800 spots resolved by two-dimensional gel electrophoresis (2DE) in the soluble proteomes of L-02 cells from the four different groups resulted in 10 differential proteins. To identify the differential spots, matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) was carried out; if the results from the tool were insufficient, tandem MS (MALDI-TOF-TOF-MS) was then performed. The raw data of peptide mass fingerprints (PMFs) and MS/MS spectra were searched against the IPI human data base for exact matches. Then western blot was employed to verify the result of proteomic analysis, the following result confirmed that the results of proteomic analysis were reliable. These results might provide an insight into the underlying mechanism of TCE intoxication and find biological markers for diagnosis and therapy of TCE-induced diseases.

[Advance on study development of detection of ciguatoxins]

Ciguatoxin may be a terrible coral fish toxin that can result in poisoning in people who eat fish containing ciguatoxin. Being lack of a convenient and accurate detection method for ciguatoxin, Ciguatera fish poisoning have occurred from time to time. To provide references for detection and prevention of ciguatera fish poisoning, in this paper, the current detection methods of ciguatoxin were reviewed.

Randomized multicenter phase III trial of oxaliplatin plus raltitrexed compared to oxaliplatin plus fluorouracil and leucovorin treatment in recurrent and metastatic colorectal cancer

4102

Purpose: To compare oxaliplatin (L-OHP) plus raltitrexed (RTX) with L-OHP plus fluorouracil and leucovorin (LV/5FU) for patients (pts) with recurrent and metastatic colorectal cancer(CRC). Methods: Eligible pts had to have histologically proven recurrent or metastatic CRC,not having previously received oxaliplatin as palliative chemotherapy,ECOG PS = 2,age:18∼70,and adequate hematological,renal and hepatic function.After written informed consent,pts were randomized to L-OHP:130 mg/m2 d1 + RTX: 3 mg/m2 d1 (Arm A) or + LV: 200 mg/m2 + 5FU:375 mg/m2 d1–5 (Arm B). Results: Between Jan 2005 and July 2006, 216 pts were enrolled at 15 centers in China.112 pts (mean age: 55.0 (19∼70), M/F: 57/46, PS 0/1/2: 46/53/13) were randomly assigned to A and 102 (mean age: 54.2(22∼70), M/F: 54/46, PS 0/1/2: 44/59/9) to B. 203 pts were eligible for response evaluation (A:103, B:100).The median number of cycles was 4 (1∼6) in A and 3 (1∼6) in B (P=0.1431).The RR was 29.1% (CR:2, PR:28, SD:50 , PD:23) in A and 17.0% (CR:2, PR:15, SD:46 , PD:37) in B (P=0.0437).The disease-control rate was 77.7% in A and 63.0% in B (P=0.0237). After a median follow-up of 10 months (4–16.5),92 pts had had progression of disease (40 in A and 52 in B); 73 deaths had occurred (35 in A and 38 in B), median time to progression was not reached. Following-up is ongoing.The median QoL scores for the two arms were comparable. 214 were included in the safety analyses (A:112, B:102). There was a higher incidence of neutropenia (48.2% verse 29.4%, P=0.005) and transaminase increase (49.1% verse 35.3%, P=0.041) among A. Grade 3 or 4 neutropenia was much common in pts in A than those in B (20.5% verse 4.9% , P=0.001), but was complicated by fever in only 3.6% of cases (4 pts) in A and in 2.9% of cases (3 pts) in B. No pts were dead or infectious due to neutropenia. There were similar rates of grade 3 or 4 transaminase elevation in the two groups. Vomitting and anorexia were much commoner with B. Conclusions: The L-OHP+RTX seems beneficial in recurrent and metastatic CRC, demonstrating better response rate and higher disease control rate with acceptable tolerability, maintenance of QoL and convenient administration schedule.

No significant financial relationships to disclose.

Polychlorinated dibenzo-p-dioxin and dibenzofuran concentrations in common fish species in the Pearl River Delta area, China

Polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/Fs) concentrations in 31 fish samples from 19 commonly consumed freshwater and saltwater species from the Pearl River Delta Area were analyzed. The PCDD/Fs dietary intake from fish for the local population was evaluated to provide a database for setting the national PCDD/F limits in fish for the People's Republic of China. The median concentration from the 31 fish samples was 1.27 pg/g wet weight for the total of PCDD/Fs, and the median WHO-TEQ was 0.26 pg/g wet weight, and ranged from 0.063 to 1.30 pg WHO-TEQ/g wet weight. The dominant contributors to the WHO-TEQ were 1,2,3,7,8-PeCDD and 2,3,4,7,8-PeCDF, which accounted for 38% and 28%, respectively. The dietary intake of PCDD/Fs from fish for local people was estimated to be 0.47 pg WHO-TEQ/kg bw x day. In view of the findings, the dietary of PCDD/Fs from other foods of animal origins in China should be studied in more detail as soon as possible in order that standards can be put forward to protect human health.

Evolution of VHL tumourigenesis in nerve root tissue

Haemangioblastomas are the key central nervous system manifestation of von Hippel-Lindau (VHL) disease, which is caused by germline mutation of the VHL gene. We have recently shown that 'tumour-free' spinal cord from patients with VHL disease contains microscopic, poorly differentiated cellular aggregates in nerve root tissue, which we descriptively designated 'mesenchymal tumourlets'. Here we have investigated spinal cord tissue affected by multiple tumours. We show that a small subset of mesenchymal tumourlets extends beyond the nerve root to form proliferative VHL-deficient mesenchyme and frank haemangioblastoma. We thus demonstrate that tumourlets present potential, but true precursor material for haemangioblastoma. We further show that intraradicular tumourlets consist of scattered VHL-deficient cells with activation of HIF-2alpha and HIF-dependent target proteins including CAIX and VEGF, and are associated with an extensive angiogenic response. In contrast, activation of HIF-1alpha was only observed in the later stages of tumour progression. In addition, ultrastructural examination reveals gradual transition from poorly differentiated VHL-deficient cells into vacuolated cells with a 'stromal' cell phenotype. The evolution of frank haemangioblastoma seems to involve multiple steps from a large pool of precursor lesions.

Epididymal cystadenomas and epithelial tumourlets: effects of VHL deficiency on the human epididymis

Although epididymal cystadenomas (ECAs) are among the most frequent VHL disease-associated tumours, fundamental questions about their pathogenesis have remained unanswered. Classification of ECAs is controversial, and the cell of origin is unknown. It is also unknown whether ECAs-like other VHL disease-associated tumours-arise as a result of VHL gene inactivation, and whether ECAs exhibit subsequent activation of hypoxia-inducible factor HIF. Moreover, the morphological spectrum of earliest ECA formation is unknown. In a detailed molecular pathological analysis of a series of epididymides collected from VHL patients at autopsy, we found that ECAs are true neoplasms that arise secondary to inactivation of the wild-type copy of the VHL gene, followed by early and simultaneous activation of HIF1 and HIF2 associated with up-regulation of downstream targets, including CAIX and GLUT-1. The observations also indicate that ECA formation evolves from a variety of microscopic epithelial tumourlets, and that these tumourlets are confined to the efferent ductular system. Although genetic and immunohistochemical analysis of precursor structures consistently revealed VHL gene inactivation and activation of HIF in the precursor lesions, only a small subset appears to progress into frank cystadenoma. Thus, ECA tumorigenesis in VHL disease shares fundamental principles with tumorigenesis in other affected organ systems.

Inhibition of in-stent restenosis by oral copper chelation in porcine coronary arteries

Stress-induced release of IL-1alpha and fibroblast growth factor-1 is dependent on intracellular copper and is a major driver of neointimal hyperplasia. Therefore, we assessed the effect of tetrathiomolybdate (TTM), a clinically proven copper chelator, on in-stent restenosis. Nine pigs were treated with TTM (5 mg/kg po) twice daily for 2 wk before stent implantation and for 4 wk thereafter, and nine pigs served as controls. In-stent restenosis was assessed by quantitative coronary angiography (QCA), intravascular ultrasound (IVUS), and histomorphometry. Serum ceruloplasmin activity was used as a surrogate marker of copper bioavailability. In TTM-treated animals, ceruloplasmin dropped 70 +/- 10% below baseline levels. Baseline characteristics were comparable in TTM-treated and control animals. At 4-wk follow-up, all parameters relevant to in-stent restenosis were significantly reduced in TTM-treated animals: minimal lumen diameter by QCA was 2.03 +/- 0.57 and 1.47 +/- 0.45 mm in TTM-treated and control animals, respectively (P < 0.05), percent stenosis diameter was 39% less in TTM-treated animals (27.1 +/- 16.6% vs. 44.5 +/- 16.1%, P < 0.05), minimal lumen area by IVUS was 60% larger in TTM-treated animals (4.27 +/- 1.56 vs. 2.67 +/- 1.19 mm(2), P < 0.05), and neointimal volume by histomorphometry was 37% less in TTM-treated animals (34.9 +/- 11.5 vs. 55.2 +/- 19.6 mm(3), P < 0.05). We conclude that systemic copper chelation with a clinically approved chelator significantly inhibits in-stent restenosis.

Proteomic profiling distinguishes astrocytomas and identifies differential tumor markers

Methods to permit more precise delineation of astrocytomas of different grades may have therapeutic utility. The authors selectively microdissected pure populations of cells from normal brain and astrocytomas. They performed two-dimensional protein gel electrophoresis (2DGE) followed by protein sequencing. Differential expression was confirmed immunohistochemically. 2DGE identified proteomic patterns and proteins that differentiated normal brain from tumor and distinguished astrocytomas of increasing grade.

Reducing respirator fit test errors: a multi-donning approach

As a continuation of recent studies to assess the accuracy of existing fit test methods, a multi-donning approach to fit testing is presented. As an example of that approach, a multi-donning quantitative fit test for filtering-facepiece respirators is presented and analyzed by comparing its error rates with those of the single-donning approach of current fit test methods. That analysis indicates the multi-donning fit test has the potential to reduce both the alpha error and the beta error to half that of single-donning fit tests. The alpha error is the error of failing a respirator that should pass; the beta error is the error of passing a respirator that should fail. Lowering fit test error rates for filtering-facepiece respirators is important because fit testing is an essential means of helping assure that an individual has selected an adequately fitting respirator. To reduce the alpha and beta error inherent in current fit test methods, the proposed fit test for filtering-facepiece respirators incorporates five donnings of the facepiece, unlike the single donning of existing fit test methods. The analysis presented here indicates that the multiple-donning approach reduces the element of chance in the fit test result and thereby increases the consistency and accuracy of the fit tests. The time to conduct the multi-donning test can approximate the time for current, single-donning tests by shortening the time the respirator is worn after each donning to about 10 sec. And, unlike current fit tests for filtering-facepieces that measure only faceseal leakage, the example multiple-donning fit test considered here is based on a measurement of total leakage (faceseal plus filter). Utilizing total respirator leakage can result in simpler quantitative fit test instrumentation and a fit test that is more relevant to the workplace. Further trials with human subjects are recommended in order to validate the proposed multi-donning approach.

[Detection of SARS-coronavirus in both human and animals by RT-PCR]

OBJECTIVE

To find the most suitable RT-PCR detection method for SARS-Coronavirus (SARS-CoV) detection in both human and animals, and to study the source of SARS virus by investigating the condition of virus carried by wild, domestic animals and animals sold in market.

METHODS

350 throat washes of confirmed, suspected and observed SARS cases were tested by TaqMan and molecular beacon fluorescence RT-PCR methods. 386 animals with 442 nasal-throat swabs, fecal swabs of animals and cell cultured were detected by TaqMan method and conventional RT-PCR method.

RESULTS

10 positive were detected from 41 SARS clinical confirmed cases (24.39%). The results of TaqMan and molecular beacon are basically coincident with the coincident rate of 88.89%. 18 cell cultures with CPE were detected and find 16 positive, among which, 14 were civet cats (87.5%). The detecting results of animal samples from Dongmen Market (Shenzhen) and other markets and farms in peripheral areas show that: the total positive rate of 4 kinds of wild animal (civet cat, raccoon dog, hog-badge and Chinese ferret-badge) is 39.02% , which has an significant difference (P < 0.01) compared with the positive rate of other animals as 0. The positive rate of PCR for nasal and fecal swabs from 109 major wild animals is 44.04%, but the positive rate of 145 wild live-animals is 0.

CONCLUSION

TaqMan and molecular beacon PCR methods both can be used in SARS detection.The results could support the hypothesis that animals (especially civet cat) could carry SARS virus.

[Comparison of PCDD/Fs content and profile in fish between marine and fresh water in a typical Chinese area]

OBJECTIVE

To study the dioxins (polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-p-furans, PCDD/Fs) content and profile in fish from marine and fresh water in a certain water area, and to assess the dioxins intake from fish in the local people.

METHODS

Samples were prepared using advanced technique, confirmation and quantitative analysis of Dibenzo-p-Dioxins and Dibenzo-Furans was performed by isotope dilution HRGC/HRMS using multiple ion detection mode (MID).

RESULTS

The average concentration of fish from marine and fresh water was 1.43pg/g wet weight and 3.43pg/g wet weight respectively, and WHO-TEQ concentration was 0.28 and 0.43pg/g wet weight respectively. The congener-specific profile dominated by OCDD and 2,3,7,8-TCDF, and the main contributor of toxicity was 1,2,3,7,8-PeCDD, 2,3,4,7,8-PeCDF, 2,3,7,8-TCDD. The exposure from fish for local people was estimated as 0.63 pg WHO-TEQ/kg bw x day.

CONCLUSION

The level of PCDD/Fs in fresh water fish was higher than that of marine fish with one fold. The average PCDD/Fs concentration was lower than 1.0 pg WHO-TEQ/kg, which is the maximum limit (ML) set up by European Union.

[Protein changes in human embryonic lung fibroblasts after hydroquinone stimulation using proteomic technique]

OBJECTIVE

To explore the molecular mechanism of cell response induced by hydroquinone, we investigated the protein profile after treatment with hydroquinone in human embryonic lung fibroblasts.

METHODS

After HQ treatment, cells were lysed in lysis solution, then the supernatant were collected and precipitated with acetone prior to protein concentration determination. The total cellular proteins were separated using two-dimensional gel electrophoresis and visualized by colloidal coomassie blue staining. Digital images were analyzed using Imagemaster 2.0 software. The differentially expressed protein spots were picked and digestion in gel then identified by peptide mass fingerprinting using MALDI-TOF.

RESULTS

There were 15 protein spots changed after HQ stimulation. Among them 8 protein spots were identified by PMF including some oxidative stress and cytoskeleton related proteins.

CONCLUSION

Protein profile was altered after HQ stimulation.

Molecular genetic and proteomic analysis of synchronous malignant gliomas

Described is a patient with concurrent discrete gliomas: a pleomorphic xanthoastrocytoma with anaplastic features and an anaplastic oligoastrocytoma. The distinct and morphologically dissimilar tumors demonstrated similar genetic abnormalities by loss of heterozygosity and comparative genome hybridization. Clonality and proteomic analyses highlighted an independent origin for the two tumors. Proteomic methods may prove useful in cases where the differential diagnosis and pathogenetic origin of tumors are uncertain, as well as more globally for its ability to provide insight into specific expression of proteins that may serve as unique markers of tumorigenesis or as novel targets of therapy.

[Application of mass spectrometry in the proteome research]

Electrospray ionization(ESI) and matrix-assisted laser desorption ionization(MALDI) are two kinds of newly-developed mass spectrometry techniques. The application of mass spectrometry is described in the proteome research such as MS charting, determination of molecular weight, peptide mass fingerprinting(PMF) and peptide sequence validation. The advantages of mass spectrometry are sensitive, accurate, rapid, high-throughput and automated. They have been proved a powerful technique and can be used as an important method for proteome research.

[Distribution of poly(ADP-ribose) polymerase pseudogene polymorphism and association with susceptibility to lung cancer in Chinese people]

OBJECTIVE

To study the distribution of poly(ADP-ribose) polymerase(PARP) pseudogene polymorphism and the association with susceptibility to lung cancer in Chinese people.

METHODS

The subjects of this study included 63 patients with lung cancer and 82 healthy controls matched in gender and age. Genome DNA was extracted from white blood cells. Products from PCR with a pair of specific primer were electrophoresized in agarose including EB. Under ultraviolet, observation and imaging were performed.

RESULTS

There was no significant difference in genotype between the cases and controls. The frequencies of B allele in cases and controls were 0.095 and 0.116 respectively. Whether there was B allele or not, smoking was a risk factor of lung cancer (P<0.05). As the genotype was AA and AB or BB, smoking OR was 2.28 and 4.83 respectively. Among non-smokers, the risk at lung cancer did not increase in AB or BB genotypes(P=0.202).

CONCLUSION

Frequency of B allele is relatively lower in Chinese people than in other races. In smokers, B allele may be a susceptible marker of lung cancer, and there is synergistic function between B allele and smoking.

[Studies of cost-effectiveness and cost-usefulness in radiology]

In the current context of significant increase of health care costs over the last decades, and in a system of global budget for health care, the concept of cost-effectiveness is one of the leading elements in the political decision making process for a given strategy. Therefore, it is important for the physician to be able to understand and critically interpret cost-effectiveness and cost-utility analyses. This article tries to illustrate comprehensively some of their key concepts. The perspective and the time horizon of the study should be clearly specified. The cost-effectiveness ratio is a synthetic summary based on a micro-costing approach in order to determine the true costs (numerator), and on an effectiveness (utility) assessment which should take into account the preferences of the community (denominator) in order to allow comparisons between interventions of different natures. Advances in the development of decision analysis softwares and in the standardization of the methodology of these studies have yielded considerable improvement in the reliability of their results. Several persisting methodological problems are the scope of current research, such as the discounting rate and the calculation of the minimal sample size required to reach a statistically significant threshold.

[Decision analysis in radiology]

Decision analysis is a technique which allows to clarify in an explicit, probabilistic and quantitative way the possible answers to a problem and to help the decision making process. The creation of algorithms, graphically displayed as decision trees in most cases, requires the introduction of quantitative information of two types: probabilities of the events that result from answering to the initial question, and utilities of the possible outcomes of these events. The choice of the optimal solution is based on the calculation of combinations of these data. Although the construction of models can be complex and time-consuming, their practical use has been simplified by the ease and user-friendliness of available softwares. To date, the applications of decision analysis in medicine have focused on cost-effectiveness studies and on the simulation of randomized trials. At the individual level, clinical applications of decision analysis could provide in a near future an interesting tool for the clinician involved in patient management. Even when doubts remain regarding the reliability of the data entered into the model, further sensitivity analysis provide a convenient way to test the validity of the drawn conclusions. This article hopefully offers a simplified and practical approach to basic decision analysis.

Fibrous meningioma in a patient with von Hippel-Lindau disease: a genetic analysis

Meningioma has been included in the constellation of tumors associated with von Hippel-Lindau (VHL) disease in previously published reports. It is unclear whether these tumors are an uncommon component of VHL disease or are more readily detected in these patients because of the frequency with which they undergo central nervous system imaging as part of the routine management of VHL disease. The authors report the case of a patient with VHL disease in whom a progressively enlarging supratentorial mass developed and was diagnosed as a hemangioblastoma because of its appearance on serial magnetic resonance images. At surgery the tumor displayed the typical features of a meningioma and was given the histological diagnosis of fibrous meningioma. Single-stranded conformational polymorphism analysis of the tumor DNA revealed a loss of heterozygosity at the neurofibromatosis Type 2 gene locus, known to be associated with sporadically occurring meningiomas. Despite this finding, the VHL gene locus on the allele from the patient's unaffected parent was normal. Thus it is unlikely that the occurrence of this patient's fibrous meningioma was associated with underlying VHL disease. Given the high frequency of neuroimaging sessions in patients with VHL disease, some supratentorial lesions that have been given radiological diagnoses of hemangioblastomas may be incidental meningiomas.