Development, preclinical evaluation and validation of a novel quick vascular closure device for transluminal, cardiac and radiological arterial catheterization.

Following percutaneous coronary intervention, vascular closure devices (VCDs) are increasingly used to reduce time to ambulation, enhance patient comfort, and reduce potential complications compared with traditional manual compression. Newer techniques include complicated, more or less automated suture devices, local application of pads or the use of metal clips and staples. These techniques often have the disadvantage of being time consuming, expensive or not efficient enough. The VCD failure rate in association with vascular complications of 2.0-9.5%, depending on the type of VCD, is still not acceptable. Therefore, the aim of this study is to develop a self-expanding quick vascular closure device (QVCD) made from a bioabsorbable elastic polymer that can be easily applied through the placed introducer sheath. Bioabsorbable block-co-polymers were synthesized and the chemical and mechanical degradation were determined by in vitro tests. The best fitting polymer was selected for further investigation and for microinjection moulding. After comprehensive haemocompatibility analyses in vitro, QVCDs were implanted in arterial vessels following arteriotomy for different time points in sheep to investigate the healing process. The in vivo tests proved that the new QVCD can be safely placed in the arteriotomy hole through the existing sheath instantly sealing the vessel. The degradation time of 14 days found in vitro was sufficient for vessel healing. After 4 weeks, the remaining QVCD material was covered by neointima. Overall, our experiments showed the safety and feasibility of applying this novel QVCD through an existing arterial sheath and hence encourage future work with larger calibers.

Combined copy number and mutation analysis identifies oncogenic pathways associated with transformation of follicular lymphoma.

Follicular lymphoma (FL) is typically an indolent disease, but 30-40% of FL cases transform into an aggressive lymphoma (tFL) with a poor prognosis. To identify the genetic changes that drive this transformation, we sequenced the exomes of 12 cases with paired FL and tFL biopsies and identified 45 recurrently mutated genes in the FL-tFL data set and 39 in the tFL cases. We selected 496 genes of potential importance in transformation and sequenced them in 23 additional tFL cases. Integration of the mutation data with copy-number abnormality (CNA) data provided complementary information. We found recurrent mutations of miR-142, which has not been previously been reported to be mutated in FL/tFL. The genes most frequently mutated in tFL included KMT2D (MLL2), CREBBP, EZH2, BCL2 and MEF2B. Many recurrently mutated genes are involved in epigenetic regulation, the Janus-activated kinase-signal transducer and activator of transcription (STAT) or the nuclear factor-κB pathways, immune surveillance and cell cycle regulation or are TFs involved in B-cell development. Of particular interest are mutations and CNAs affecting S1P-activated pathways through S1PR1 or S1PR2, which likely regulate lymphoma cell migration and survival outside of follicles. Our custom gene enrichment panel provides high depth of coverage for the study of clonal evolution or divergence.

Recurrent activating mutations of CD28 in peripheral T-cell lymphomas.

Peripheral T-cell lymphomas (PTCLs) comprise a heterogeneous group of mature T-cell neoplasms with a poor prognosis. Recently, mutations in TET2 and other epigenetic modifiers as well as RHOA have been identified in these diseases, particularly in angioimmunoblastic T-cell lymphoma (AITL). CD28 is the major co-stimulatory receptor in T cells which, upon binding ligand, induces sustained T-cell proliferation and cytokine production when combined with T-cell receptor stimulation. We have identified recurrent mutations in CD28 in PTCLs. Two residues-D124 and T195-were recurrently mutated in 11.3% of cases of AITL and in one case of PTCL, not otherwise specified (PTCL-NOS). Surface plasmon resonance analysis of mutations at these residues with predicted differential partner interactions showed increased affinity for ligand CD86 (residue D124) and increased affinity for intracellular adaptor proteins GRB2 and GADS/GRAP2 (residue T195). Molecular modeling studies on each of these mutations suggested how these mutants result in increased affinities. We found increased transcription of the CD28-responsive genes CD226 and TNFA in cells expressing the T195P mutant in response to CD3 and CD86 co-stimulation and increased downstream activation of NF-κB by both D124V and T195P mutants, suggesting a potential therapeutic target in CD28-mutated PTCLs.

Intrajugular balloon catheter reduces air embolism in vitro and in vivo.

BACKGROUND: Neurosurgical procedures requiring a sitting position may put the patient at risk of a potentially life-threatening air embolism. Transient manual jugular venous compression limits further air entry in this situation. This study presents an alternative technique aimed at reducing the risk of air embolism. METHODS: In an in vitro model, an intrajugular balloon catheter was inserted to demonstrate that this device prevents air embolism. In an in vivo study, this device was bilaterally placed into jugular vessels in pigs. Using an ultrasound technique, blood flow was monitored and jugular venous pressure was recorded before and during cuff inflation. Air was applied proximally to the inflated cuffs to test the hypothesis that this novel device blocks air passage. RESULTS: In vitro, the intrajugular balloon catheter reliably prevented further air entry (n=10). Additionally, accumulated air could be aspirated from an orifice of the catheter (n=10). In vivo, inflation of the catheter balloon completely obstructed venous blood flow (n=8). Bilateral inflation of the cuff significantly increased the proximal jugular venous pressure from 9.8 (2.4) mm Hg to 14.5 (2.5) mm Hg (n=8, P<0.05). Under conditions mimicking an air embolism, air passage across the inflated cuffs was prevented and 78 (20%) (n=6) of the air dose could be aspirated by the proximal orifice of the catheter. CONCLUSIONS: These findings may serve as a starting point for the development of intrajugular balloon catheters designed to reduce the risk of air embolism in patients undergoing neurosurgery in a sitting position.

Short-acting P2Y12 blockade to reduce platelet dysfunction and coagulopathy during experimental extracorporeal circulation and hypothermia.

BACKGROUND: Extracorporeal circulation (ECC) and hypothermia are routinely used in cardiac surgery to maintain stable circulatory parameters and to increase the ischaemic tolerance of the patient. However, ECC and hypothermia cause platelet activation and dysfunction possibly followed by a devastating coagulopathy. Stimulation of the adenosinediphosphate (ADP) receptor P(2)Y(12) plays a pivotal role in platelet activation. This experimental study tested P(2)Y(12) receptor blockade as an approach to protect platelets during ECC. METHODS: Human blood was treated with the short-acting P(2)Y(12) blocker cangrelor (1 µM, t(1/2)<5 min) or the P(2)Y(12) inhibitor 2-MeSAMP (100 µM) and circulated in an ex vivo ECC model at normothermia (37°C) and hypothermia (28°C). Before and after circulation, markers of platelet activation and of coagulation (thrombin-antithrombin complex generation) were analysed. During hypothermic ECC in pigs, the effect of reversible P(2)Y(12) blockade on platelet function was evaluated by cangrelor infusion (0.075 µg kg(-1) min(-1)). RESULTS: During ex vivo hypothermic ECC, P(2)Y(12) blockade inhibited platelet granule release (P<0.01), platelet-granulocyte binding (P<0.05), and platelet loss (P<0.001), whereas no effects on platelet-ECC binding, platelet CD42bα expression, glycoprotein IIb/IIIa activation, or thrombin-antithrombin complex generation were observed. During hypothermic ECC in pigs, cangrelor inhibited platelet-fibrinogen binding (P<0.05) and ADP-induced platelet aggregation (P<0.001). Platelet function was rapidly restored after termination of cangrelor infusion. CONCLUSIONS: P(2)Y(12) blockade by cangrelor prevents platelet activation during ECC and hypothermia. Owing to its short half-life, platelet inhibition can be well controlled, thus potentially reducing bleeding complications. This novel pharmacological strategy has the potential to reduce complications associated with ECC and hypothermia.

Introducing a large animal model to create urethral stricture similar to human stricture disease: a comparative experimental microscopic study.

PURPOSE: In this tissue engineering study we investigated urethral stricture formation to evaluate different treatment modalities in the large animal model and validate the most current, comparable effect of human stricture development for successful human clinical application. MATERIALS AND METHODS: In 12 male minipigs stricture formation was evaluated by urethrography 1, 8 and 12 weeks after stricture induction by ligation, urethrotomy or thermocoagulation. Normal human urethral and scar tissue of 6 patients was harvested and compared to animal specimens. The effect of urethral damage was investigated for microvessel density and collagen I:III ratio. RESULTS: A week after urethrotomy urothelium covered the spongiosum tissue, showing minimal infiltration of lymphocytes and macrophages, and sporadic eosinophil granulocytes. However, increased connective tissue was observed with time as well as urethral luminal narrowing, vascular network loss (decreased microvessel density) and significantly increased collagen with a favorably revised collagen type I:III ratio. The 3 methods of stricture induction resulted in different stricture severity in the animal model (thermocoagulation >ligation >urethrotomy). Porcine urethral samples after thermocoagulation showed a significantly increased collagen I:III ratio (p <0.001), almost equal to that of human urethral stricture specimens. CONCLUSIONS: We successfully developed a large animal model in which to study urethral stricture formation by defined iatrogenic intervention. The established animal model advances investigation to evaluate new therapy modalities in a preclinical setting to treat urethral stricture and predict clinical outcome.

DEHP and its active metabolites: leaching from different tubing types, impact on proinflammatory cytokines and adhesion molecule expression. Is there a subsumable context?

INTRODUCTION: Di(2-ethylhexyl)phthalate (DEHP) is suspected to be toxic for several reasons. During contact with a lipophilic medium, DEHP leaks from polyvinylchloride (PVC), but its influence on inflammatory reactions remains unknown. We examined specific DEHP leaching out of different tubing types, the possibly modulated liberation of proinflammatory cytokines and the induction of adhesion molecule expression in primary endothelial cells. MATERIALS AND METHODS: Blood samples were circulated in traditional PVC, nodioctyl phthalate (DOP) PVC and heparin-coated PVC tubing within a Chandler loop model. The blood was tested for the concentration of DEHP and its active metabolites as well as the liberation of the proinflammatory cytokines TNFα and IL1ß. Furthermore, we exposed human endothelial cells to circulated blood and analysed them for the expression of the adhesion molecules ICAM-1, VCAM-1 and E-selectin. RESULTS: In contrast to the other tubing, PVC tubing showed significantly elevated DEHP levels, but no alteration was observed concerning a potential up-regulation of the cytokines or activation of the endothelial adhesion molecule receptors. CONCLUSIONS: Our data conclude that there is no correlation between DEHP leaching and the inflammatory response after ECC support, but this study showed that even DEHP-free material is leaching DEHP and its toxic metabolites.

Clinical and molecular characterization of diffuse large B-cell lymphomas with 13q14.3 deletion.

BACKGROUND: Deletions at 13q14.3 are common in chronic lymphocytic leukemia and are also present in diffuse large B-cell lymphomas (DLBCL) but never in immunodeficiency-related DLBCL. To characterize DLBCL with 13q14.3 deletions, we combined genome-wide DNA profiling, gene expression and clinical data in a large DLBCL series treated with rituximab, cyclophosphamide, doxorubicine, vincristine and prednisone repeated every 21 days (R-CHOP21). PATIENTS AND METHODS: Affymetrix GeneChip Human Mapping 250K NspI and U133 plus 2.0 gene were used. MicroRNA (miRNA) expression was studied were by real-time PCR. Median follow-up of patients was 4.9 years. RESULTS: Deletions at 13q14.3, comprising DLEU2/MIR15A/MIR16, occurred in 22/166 (13%) cases. The deletion was wider, including also RB1, in 19/22 cases. Samples with del(13q14.3) had concomitant specific aberrations. No reduced MIR15A/MIR16 expression was observed, but 172 transcripts were significantly differential expressed. Among the deregulated genes, there were RB1 and FAS, both commonly deleted at genomic level. No differences in outcome were observed in patients treated with R-CHOP21. CONCLUSIONS: Cases with 13q14.3 deletions appear as group of DLBCL characterized by common genetic and biologic features. Deletions at 13q14.3 might contribute to DLBCL pathogenesis by two mechanisms: deregulating the cell cycle control mainly due RB1 loss and contributing to immune escape, due to FAS down-regulation.

Veins are no arteries: even moderate arterial pressure induces significant adhesion molecule expression of vein grafts in an ex vivo circulation model.

AIM: Coronary artery bypass grafting (CABG) is a standard procedure for treatment of coronary heart disease. Eighty percent of all CABGs are performed with venous grafts which then get exposed to an arterial pressure after surgery. This widely used procedure, however, is complicated by the development of alterations in the vein graft wall, leading to a decreased patency rate and graft failure. This study enlightens the influence of an even moderate arterial pressure on the gene expression of adhesion molecules in venous grafts which play a decisive role for the early induction of atherogenesis. METHODS: Segments of porcine vena jugularis and arteria carotis were mounted in a simulated bypass circuit and subjected to pulsatile flow. Vessel segments were examined for adhesion molecule expression with quantitative real-time - polymerase chain reaction (qRT-PCR) and adherence of leukocytes was observed by confocal laser scanning microscopy and scanning electron microscopy. RESULTS: Veins grafts subjected to an even moderate arterial pressure showed a 14-fold increase of ICAM-1 expression already after 4 hours. An arterial pressure of around 100/80 mmHg was enough to stimulate the adhesion molecule expression Furthermore it led to a 9-fold increase of leukocyte adhesion to the venous endothelium, but, in contrast this was not the case in arteries. CONCLUSION: This study showed, that already 100 mmHg upregulates the expression of several adhesion molecules in pig veins followed by increased adhesion of leukocytes. Therefore, our data demonstrate the advantage of arteries for CABG, and that new therapeutic strategies are urgently necessary to protect vein grafts either physically or pharmacologically if arteries are not available for CABG.

Natural killer cell lymphoma shares strikingly similar molecular features with a group of non-hepatosplenic γδ T-cell lymphoma and is highly sensitive to a novel aurora kinase A inhibitor in vitro.

Natural killer (NK) cell lymphomas/leukemias are rare neoplasms with an aggressive clinical behavior. The majority of the cases belong to extranodal NK/T-cell lymphoma, nasal type (ENKTL) in the current WHO classification scheme. Gene-expression profiling (GEP) of 21 ENKTL and NK-cell lymphoma/leukemia patients, 17 NK- and T-cell lines and 5 indolent NK-cell large-granular-lymphocytic proliferation was performed and compared with 125 peripheral T-cell lymphoma (PTCL) patients previously studied. The molecular classifier derived for ENKTL patients was comprised of 84 transcripts with the majority of them contributed by the neoplastic NK cells. The classifier also identified a set of γδ-PTCLs both in the ENKTL cases as well as in cases initially classified as PTCL-not otherwise specified. These γδ-PTCLs expressed transcripts associated with the T-cell receptor (TCR)/CD3 complex, suggesting T cell rather than NK-cell lineage. They were very similar to NK-cell tumors by GEP, but were distinct from cytotoxic (αß)-PTCL and hepatosplenic T-cell lymphoma, indicating derivation from an ontogenically and functionally distinct subset of γδ T cells. They showed distinct expression of Vγ9, Vδ2 transcripts and were positive for TCRγ, but negative for TCRß by immunohistochemistry. Targeted inhibition of two oncogenic pathways (AURKA and NOTCH-1) by small-molecular inhibitors induced significant growth arrest in NK-cell lines, thus providing a rationale for clinical trials of these inhibitors in NK-cell malignancies.

Stromal gene signatures in large-B-cell lymphomas.

BACKGROUND: The addition of rituximab to combination chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP), or R-CHOP, has significantly improved the survival of patients with diffuse large-B-cell lymphoma. Whether gene-expression signatures correlate with survival after treatment of diffuse large-B-cell lymphoma is unclear. METHODS: We profiled gene expression in pretreatment biopsy specimens from 181 patients with diffuse large-B-cell lymphoma who received CHOP and 233 patients with this disease who received R-CHOP. A multivariate gene-expression-based survival-predictor model derived from a training group was tested in a validation group. RESULTS: A multivariate model created from three gene-expression signatures--termed "germinal-center B-cell," "stromal-1," and "stromal-2"--predicted survival both in patients who received CHOP and patients who received R-CHOP. The prognostically favorable stromal-1 signature reflected extracellular-matrix deposition and histiocytic infiltration. By contrast, the prognostically unfavorable stromal-2 signature reflected tumor blood-vessel density. CONCLUSIONS: Survival after treatment of diffuse large-B-cell lymphoma is influenced by differences in immune cells, fibrosis, and angiogenesis in the tumor microenvironment.

DNA methylation profiles in diffuse large B-cell lymphoma and their relationship to gene expression status.

In an initial epigenetic characterization of diffuse large B-cell lymphoma (DLBCL), we evaluated the DNA methylation levels of over 500 CpG islands. Twelve CpG islands (AR, CDKN1C, DLC1, DRD2, GATA4, GDNF, GRIN2B, MTHFR, MYOD1, NEUROD1, ONECUT2 and TFAP2A) showed significant methylation in over 85% of tumors. Interestingly, the methylation levels of a CpG island proximal to FLJ21062 differed between the activated B-cell-like (ABC-DLBCL) and germinal center B-cell-like (GCB-DLBCL) subtypes. In addition, we compared the methylation and expression status of 67 genes proximal (within 500 bp) to the methylation assays. We frequently observed that hypermethylated CpG islands are proximal to genes that are expressed at low or undetectable levels in tumors. However, many of these same genes were also poorly expressed in DLBCL tumors where their cognate CpG islands were hypomethylated. Nevertheless, the proportional reductions in BNIP3, MGMT, RBP1, GATA4, IGSF4, CRABP1 and FLJ21062 expression with increasing methylation suggest that epigenetic processes strongly influence these genes. Lastly, the moderate expression of several genes proximal to hypermethylated CpG tracts suggests that DNA methylation assays are not always accurate predictors of gene silencing. Overall, further investigation of the highlighted CpG islands as potential clinical biomarkers is warranted.

Elevated Mdm2 expression induces chromosomal instability and confers a survival and growth advantage to B cells.

Mdm2, a regulator of the p53 tumor suppressor, is frequently overexpressed in lymphomas, including lymphomas that have inactivated p53. However, the biological consequences of Mdm2 overexpression in lymphocytes are not fully resolved. Here, we report that increased expression of Mdm2 in B cells augmented proliferation and reduced susceptibility to p53-dependent apoptosis, which was due to inhibition of p53 and suppression of p21 expression. Notably, developing and mature B cells from Mdm2 transgenic mice had an increased frequency of chromosomal/chromatid breaks and/or aneuploidy. This Mdm2-mediated genome instability occurred at a similar frequency as that in B cells overexpressing the oncogene c-Myc, but the chromosomal instability was not further enhanced when Mdm2 and c-Myc were overexpressed together. Elevated Mdm2 expression alone increased the occurrence of B-cell transformation in vivo and cooperated with c-Myc overexpression, resulting in an acceleration of B-cell lymphomagenesis. In addition, the frequency of p53 mutations was reduced, but not eliminated, in lymphomas arising in Mdm2/Emu-myc double transgenic mice. Therefore, increased Mdm2 expression facilitated B-cell lymphomagenesis, in part, through regulation of p53 by altering B-cell proliferation and susceptibility to apoptosis, and by inducing chromosomal instability.

Sustainable universal salt iodization in low-income countries - time to re-think strategies?

OBJECTIVE: Sustained iodine deficiency control requires sustainable mechanisms for iodine supplementation. We aim to describe the status of salt iodation machines, salt producers' experiences and quality of salt produced in Tanzania. METHODS: Qualitative and quantitative data was collected from the factory sites, observations were made on the status of UNICEF-supplied assisted-iodation machines and convenience samples of salt from 85 salt production facilities were analysed for iodine content. RESULTS: A total of 140 salt works visited had received 72 salt iodation machines in 1990s, but had largely abandoned them due to high running and maintenance costs. Locally devised simple technology was instead being used to iodate salt. High variability of salt iodine content was found and only 7% of samples fell within the required iodation range. CONCLUSION: Although iodine content at factory level is highly variable, overall iodine supply to the population has been deemed largely sufficient. The need for perpetual iodine fortification requires reassessment of salt iodation techniques and production-monitoring systems to ensure sustainability. The emerging local technologies need evaluation as alternative approaches for sustaining universal salt iodation in low-income countries with many small-scale salt producers.

Bacterial contamination and over-dilution of commercial infant formula prepared by HIV-infected mothers in a Prevention of Mother-to-Child Transmission (PMTCT) Programme, South Africa.

To examine the safety of formula feeds used by mothers participating in a Prevention of Mother-to-Child Transmission (PMTCT) programme, contents of 94 feeding bottles collected at a PMTCT-clinic were analysed. An additional 17 samples were taken from already prepared feeds during home visits, as well as 21 samples from bottles prepared under observation. Living conditions and educational levels were overall good and mothers had been counselled on safe formula preparation. Samples were analysed for faecal bacteria, using Escherichia coli and Enterococcus sp. as indicators. Protein concentration was used as an indicator of concentration of the formula. Out of 94, 63 (67%) of samples obtained at the clinic and 13/16 (81%) of available home samples were contaminated with faecal bacteria, compared to 8/21 (38%) of those prepared under observation. Out of 94, 58 (62%) of the clinic samples containing E. coli and 23/94 (24%) of those containing Enterococcus sp. were contaminated with more than the US government recommended limit of 10 CFU/ml. Out of 94, 26 (28%) of samples obtained at the clinic, 8/17 (47%) of home samples and 3/21 (14%) of those prepared under observation were over-diluted, compared to standards. Many mothers did not follow recommended practices in preparing and feeding the bottles.

Aptamer-based isolation and subsequent imaging of mesenchymal stem cells in ischemic myocard by magnetic resonance imaging.

PURPOSE: Mesenchymal stem cells (MSC) seem to be a promising cell source for cellular cardiomyoplasty. We recently developed a new aptamer-based specific selection of MSC to provide "ready to transplant" cells directly after isolation. We evaluated MRI tracking of newly isolated and freshly transplanted MSC in the heart using one short ex vivo selection step combining specific aptamer-based isolation and labeling of the cells. MATERIALS AND METHODS: Bone marrow (BM) was collected from healthy pigs. The animals were euthanized and the heart was placed in a perfusion model. During cold ischemia, immunomagnetic isolation of MSC from the BM by MSC-specific aptamers labeled with Dynabeads was performed within 2 h. For histological identification the cells were additionally stained with PKH26. Approx. 3 x 10(6) of the freshly aptamer-isolated cells were injected into the ramus interventricularis anterior (RIVA) and 5 x 10(5) cells were injected directly into myocardial tissue after damaging the respective area by freezing (cryo-scar). 3 x 10(6) of the aptamer-isolated cells were kept for further characterization (FACS and differentiation assays). 20 h after cell transplantation, MRI of the heart using a clinical 3.0 Tesla whole body scanner (Magnetom Trio, Siemens, Germany) was performed followed by histological examinations. RESULTS: The average yield of sorted cells from 120 ml BM was 7 x 10(6) cells. The cells were cultured and showed MSC-like properties. MRI showed reproducible artifacts within the RIVA-perfusion area and the cryo-scar with surprisingly excellent quality. The histological examination of the biopsies showed PKH26-positive cells within the areas which were positive in the MRI in contrast to the control biopsies. CONCLUSION: Immunomagnetic separation of MSC by specific aptamers linked to magnetic particles is feasible, effective and combines a specific separation and labeling technique to a "one stop shop" strategy.

The effects of a 3-year obesity intervention in schoolchildren in Beijing.

BACKGROUND: Childhood obesity has become a health problem in urban areas in China. Intervention to reduce childhood obesity should be of high priority. School-based intervention programmes are needed to deal with the growing prevalence of childhood obesity in China. METHODS: Five primary schools were selected randomly for this study in the Beijing urban area in China; two were allocated to the intervention group and three to the control group. A total of 2425 children (1029 children in intervention schools and 1396 children in control schools) took part in the study for 3 years. In the intervention group, children and their parents were involved in a programme of nutrition education and physical activity. Control school students followed their usual health and physical education curriculum with no extra intervention. RESULTS: After the 3-year intervention, the prevalence of overweight and obesity were significantly lower in the intervention schools than in the control schools (overweight: 9.8% vs. 14.4%, P < 0.01; obesity: 7.9% vs. 13.3%, P < 0.01). The prevalence of overweight and obesity decreased by 26.3% and 32.5% in intervention schools respectively after intervention. The prevalence of overweight and obesity increased in control schools. There was also significant difference in body mass index between intervention and control schools (18.2 +/- 2.6 vs. 20.3 +/- 3.4, P < 0.01) after intervention. More non-obese children became obese in the control schools (7.0%) than in the intervention schools (2.4%) at end line (P < 0.01). Among the children who were obese at baseline, 49.2% remained obese at end line in intervention schools while 61.9% remained obese in control schools (P < 0.01). CONCLUSIONS: Our study showed that an intervention programme could be feasible in schools in Beijing, China. The prevalence of overweight and obesity was reduced in schoolchildren in Beijing through an intervention focused on nutrition education and physical activity. Overweight and obesity children as well as normal weight children and their parents should be involved in such an intervention programme.

Distinctive patterns of BCL6 molecular alterations and their functional consequences in different subgroups of diffuse large B-cell lymphoma.

Gene expression profiling of diffuse large B-cell lymphoma (DLBCL) has revealed biologically and prognostically distinct subgroups: germinal center B-cell-like (GCB), activated B-cell-like (ABC) and primary mediastinal (PM) DLBCL. The BCL6 gene is often translocated and/or mutated in DLBCL. Therefore, we examined the BCL6 molecular alterations in these DLBCL subgroups, and their impact on BCL6 expression and BCL6 target gene repression. BCL6 translocations at the major breakpoint region (MBR) were detected in 25 (18.8%) of 133 DLBCL cases, with a higher frequency in the PM (33%) and ABC (24%) subgroups than in the GCB (10%) subgroup. Translocations at the alternative breakpoint region (ABR) were detected in five (6.4%) of 78 DLBCL cases, with three cases in ABC and one case each in the GCB and the unclassifiable subgroups. The translocated cases involved IgH and non-IgH partners in about equal frequency and were not associated with different levels of BCL6 mRNA and protein expression. BCL6 mutations were detected in 61% of DLBCL cases, with a significantly higher frequency in the GCB and PM subgroups (>70%) than in the ABC subgroup (44%). Exon-1 mutations were mostly observed in the GCB subgroup. The repression of known BCL6 target genes correlated with the level of BCL6 mRNA and protein expression in GCB and ABC subgroups but not with BCL6 translocation and intronic mutations. No clear inverse correlation between BCL6 expression and p53 expression was observed. Patients with higher BCL6 mRNA or protein expression had a significantly better overall survival. The biological role of BCL6 in translocated cases where repression of known target genes is not demonstrated is intriguing and warrants further investigation.

Portal hyperperfusion causes disturbance of microcirculation and increased rate of hepatocellular apoptosis: investigations in heterotopic rat liver transplantation with portal vein arterialization.

Clinical results of portal vein arterialization (PVA) in liver transplantation are controversial. One reason for this is the lack of a standardized flow regulation. Our experiments in rats compared PVA with blood-flow regulation to PVA with hyperperfusion in heterotopic auxiliary liver transplantation (HALT). In group I (n = 19), the graft's portal vein was completely arterialized via the right renal artery in-stent technique, using a 0.3-mm stent, leading to a physiological average portal blood flow. In group II (n = 19), a 0.5-mm stent was used. In group II, the average portal blood flow after reperfusion was significantly elevated (group II: 6.4 +/- 1.5; group I: 1.7 +/- 0.4 mL/min/g of liver weight; P < .001). The sinusoidal diameter after reperfusion was significantly greater in group II (9.8 +/- 0.5 microm) than in group I (5.5 +/- 0.2 microm; P < .001). Red blood cell velocity in the dilated sinusoids was significantly lower in group II (171 +/- 18 microm/s) than in group I (252 +/- 13 microm/s). Stasis of erythrocytes occurred; consequently, the functional sinusoidal density was significantly reduced in group II (38 +/- 7%) compared with group I (50 +/- 3%; P < .01). Two hours after reperfusion of the portal vein, the number of apoptotic hepatocytes was significantly higher in group II than in group I (I: 0 +/- 0 vs II: 7 +/- 9 M30-positive hepatocytes/10 high-power fields). The 6-week survival rate was 9 of 11 in both groups. In group II, 6 of 9 grafts showed massive hepatocellular necroses after 6 weeks, whereas in group I, only 1 of 9 presented a slight hepatocellular necrosis. Finally, our results demonstrate negative effects of portal hyperperfusion in transplanted livers, which are correctable by adequate flow regulation.

Decreased Mdm2 expression inhibits tumor development induced by loss of ARF.

The tumor suppressor p14/p19(ARF) regulates Mdm2, which is known for controlling the p53 tumor suppressor. Here we report that loss of one allele of Mdm2 in cells that lack ARF resulted in a decreased rate of proliferation, fewer chromosomal aberrations, and suppression of Ras-induced transformation. Moreover, a haploinsufficiency of Mdm2 inhibited spontaneous tumor development in ARF-null mice. Remarkably, Mdm2(+/-)ARF(-/-) mice survived an average of 6 months longer than Mdm2(+/+)ARF(-/-) mice. The spectrum of tumors that arose in Mdm2(+/-)ARF(-/-) mice did not significantly differ from those that developed in mice lacking only ARF. However, the extended tumor latency allowed for the emergence of multiple primary tumors in a third of the Mdm2(+/-)ARF(-/-) mice, as compared to the single tumor type that arose in ARF-null only mice. Therefore, a decrease in Mdm2 levels restored regulation of critical cellular processes that are altered during transformation and that occur in the absence of ARF. Our findings also indicate that Mdm2 can function independently from ARF and imply that targeting Mdm2 in tumors that lack ARF expression should be an effective therapeutic approach.