Occam's razor on the mechanism of resistive-wall-mode-induced β limits in diverted tokamaks

External kink modes, believed to be the drive of the β-limiting resistive wall mode, are strongly stabilized by the presence of a separatrix. We thus propose a novel mechanism explaining the appearance of long-wavelength global instabilities in free boundary high-β diverted tokamaks, retrieving the experimental observables within a physical framework dramatically simpler than most of the models employed for the description of such phenomena. It is shown that the magnetohydrodynamic stability is worsened by the synergy of β and plasma resistivity, with wall effects significantly screened in an ideal, i.e., with vanishing resistivity, plasma with separatrix. Stability can be improved by toroidal flows, depending on the proximity to the resistive marginal boundary. The analysis is performed in tokamak toroidal geometry, and includes averaged curvature and essential separatrix effects.

Excitation Mechanism of Low-n Edge Harmonic Oscillations in Edge Localized Mode-Free, High Performance, Tokamak Plasmas

The excitation mechanism for low-n edge harmonic oscillations in quiescent H-mode regimes is identified analytically. We show that the combined effect of diamagnetic and poloidal magnetohydrodynamic flows, with the constraint of a Doppler-like effect of the ion flow, leads to the stabilization of short wavelength modes, allowing low-n perturbation to grow. The analysis, performed in tokamak toroidal geometry, includes the effects of large edge pressure gradients, associated with the local flattening of the safety factor and diamagnetic flows, sheared parallel and E×B rotation, and a vacuum region between plasma and the ideal metallic wall. The separatrix also is modeled analytically.

SURF1 knockout cloned pigs: Early onset of a severe lethal phenotype

Leigh syndrome (LS) associated with cytochrome c oxidase (COX) deficiency is an early onset, fatal mitochondrial encephalopathy, leading to multiple neurological failure and eventually death, usually in the first decade of life. Mutations in SURF1, a nuclear gene encoding a mitochondrial protein involved in COX assembly, are among the most common causes of LS. LSSURF1 patients display severe, isolated COX deficiency in all tissues, including cultured fibroblasts and skeletal muscle. Recombinant, constitutive SURF1-/- mice show diffuse COX deficiency, but fail to recapitulate the severity of the human clinical phenotype. Pigs are an attractive alternative model for human diseases, because of their size, as well as metabolic, physiological and genetic similarity to humans. Here, we determined the complete sequence of the swine SURF1 gene, disrupted it in pig primary fibroblast cell lines using both TALENs and CRISPR/Cas9 genome editing systems, before finally generating SURF1-/- and SURF1-/+ pigs by Somatic Cell Nuclear Transfer (SCNT). SURF1-/- pigs were characterized by failure to thrive, muscle weakness and highly reduced life span with elevated perinatal mortality, compared to heterozygous SURF1-/+ and wild type littermates. Surprisingly, no obvious COX deficiency was detected in SURF1-/- tissues, although histochemical analysis revealed the presence of COX deficiency in jejunum villi and total mRNA sequencing (RNAseq) showed that several COX subunit-encoding genes were significantly down-regulated in SURF1-/- skeletal muscles. In addition, neuropathological findings, indicated a delay in central nervous system development of newborn SURF1-/- piglets. Our results suggest a broader role of sSURF1 in mitochondrial bioenergetics.

Combined use of a wristband and a smartphone to reduce body weight in obese children: randomized controlled trial

BACKGROUND

Technological instruments may help control paediatric obesity.

OBJECTIVE

We tested whether a personalized programme based on the energy expenditure obtained from a wristband (WB) and the energy intake obtained from a smartphone application (APP) is superior to a standard approach at promoting weight loss.

METHODS

We performed a randomized controlled trial in obese children aged 10-17 years. The experimental (EXP) and control (CTR) groups were given a low-energy diet and a prescription for physical activity. The EXP group was equipped with a WB and an APP and given personalized feedback every 7 days. The main outcome was weight loss at 3 months.

RESULTS

The mean (standard deviation) z-score of body mass index at the enrollment was 2.20 (0.47) in the EXP (n = 16 out of 23) and 2.09 (0.34) in the CTR group (n = 14 out of 20) of children who completed the trial. The mean (95%CI) difference in weight loss at 3 months was 0.07 kg (95%CI: 2.81 to 2.96) for EXP vs. the CTR.

CONCLUSION

A personalized lifestyle programme based on a WB and an APP was not superior to a standard lifestyle programme at promoting weight loss in obese children.

431 GENERATION OF CLONED CD55-CD39 TRANSGENIC α1,3-GALACTOSYLTRANSFERASE DEPLETED (GAL - / - ) PIGLETS

Success in xenotransplantation relies on engineering of the pig genome to express human transgenes, such as CD55/CD39, that can control coagulation and inflammation to prolong the graft survival of a 1,3-galactosyltransferase depleted (Gal-/-) pig organs in nonhuman primates and then able to bypass the hyperacute rejection. The aim of our work was to produce Gal-/- piglets overexpressing CD55/CD39. In experiment (Exp.) 1 exploiting 2 ubiquitous expression vectors (pCAGGS-CD55 and pCAGGS-CD39), we transfected immortalized porcine kidney cells (PK15) with CD55 and CD39 using Nucleofector (Amaxa Biosystems, Cologne, Germany) and selected 5 cell colonies each (PK15-CD55 and PK15-CD39) that were expanded and analyzed by RT-PCR, immunohistochemistry (IHC) and Western blot (WB). The monoclonal antibodies IA10 for hCD55 and BU61 for hCD39 were used. Transgenic transcription was confirmed by Northern blot (NB) using digoxigenin-labeled probes. In Exp. 2, a neonatal pig Gal-/- fibroblast line was co-transfected by Nucleofector using 2 ubiquitous expression vectors (hEF-CD55 and pCAGGS-CD39) for the expression of CD55 and CD39. Colonies were analyzed by RT-PCR and IHC only, because of the limited number of cells available. Cells from one colony with a high level of CD55/CD39 expression according to IHC were used for nuclear transfer into enucleated oocytes. Day 5 compact morula/blastocyst (n = 144) were transplanted in 2 synchronized sows. Porcine aortic endothelial cells (PAEC) and fibroblasts derived from 2 stillborn piglets were analysed with IHC, NB, and WB. The expression level of transgenes from both experiments was compared with human umbilical vein endothelial cells (HUVEC) by fluorescence-activated cell sorting (FACS), using IA10, BRIC110, IH4, 2G2, and MEM-118 antibodies for hCD55 and TU66 for hCD39. In Exp. 1, RT-PCR showed CD55 mRNA expression in 3 out of 5 (2, 15, 24) PK15-CD55 colonies. A high level of CD55 expression was confirmed only in colony 24 by IHC, NB, WB, and FACS. Low expression level in colony 2 revealed by FACS was not detected by IHC, indicating that FACS analysis is more accurate to quantify the level of expression. All PK15-CD39 colonies were positive according to RT-PCR and IHC. Only one colony PK15-CD39 was further analyzed by NB and WB and confirmed positive. In Exp. 2, IHC, NB, WB, and FACS analyses of fibroblasts and PAEC derived from both cloned piglets confirmed the high level of CD39 expression detected by IHC in donor cells used for nuclear transfer. However, strong CD55 expression detected by IHC was not confirmed by NB analyses and, by FACS, was lower than in HUVEC cells. In conclusion, we produced cloned CD55-CD39 transgenic Gal-/- piglets with a high level of CD39 expression but the expression level of CD55 was lower than in HUVEC cells. We found that although IHC is the method of choice in preliminary screening, it is not sufficiently quantitative when only a few cells for each clone are available. Thus, IHC needs to be complemented with additional methods (e.g. WB, FACS, real-time RT-PCR) to obtain complete evaluation of the expression pattern of transgenes before nuclear transfer experiments. This study was supported by EU grant no. LSHB-CT-2006-037377 and Fondazione Banca Popolare di Cremona.

300 HEMIZYGOUS PRION PROTEIN GENE (PRNP) KNOCKOUT IN CATTLE FIBROBLASTS

Bovine spongiform encephalopathy (BSE) represents a real threat for human health, as has been demonstrated by the causal link with the variant form of Creutzfeldt-Jakob disease. The aim of our project is to create a bovine strain knockout for the prion protein gene (PRNP) that should be resistant to BSE infection. We combined the use of homologous recombination by PRNP targeting vectors in bovine fibroblasts with the subsequent use of nuclear transfer (NT). We transfected fetal (male) and adult (female) bovine fibroblasts by nucleofection, using targeting vectors disrupting the PRNP by means of loxP flanked cassettes. They expressed resistance to different drugs driven by a PGK or TK promoter and the thymidine kinase gene as a negative selection marker. We screened, by PCR, 907 drug-resistant colonies, from which we identified 8 Neo-resistant colonies with a recombined PRNP allele (overall efficiency 3.2%; 7/108 from fetal, 1/145 from adult; P < 0.5). Fibroblasts PRNP+/– Neo were used to produce NT blastocysts from which neural precursors cell lines were established (Lazzari et al. 2006 Stem Cells 24, 2514–2521). These lines were capable of extensive proliferation (over 120 doublings during 4 months of culture) and provided unlimited material for Southern blot analysis to confirm PCR findings. Three clones (2 from fetal and 1 from adult) were further analyzed and confirmed PRNP+/– by Southern blot and were subsequently used for NT to generate blastocysts for transfer to recipient heifers. On Day +40 of gestation, the pregnancy rate was 33.3% (9/30) for the fetal line and 50% (2/4) for the adult line. One of the fetuses originating from fetal fibroblasts was removed on Day +45 to establish a rejuvenated fibroblast cell line used for a second round of gene targeting to obtain a PRNP –/– clone. We nucleofected these fibroblasts with Puro, Hygro, and promoterless Hygro cassette-carrying targeting vectors. We screened 625 drug-resistant colonies by PCR but none tested positive for the second targeting. In conclusion, we have obtained heterozygous PRNP+/– fibroblasts with the Neo vector both in fetal and adult fibroblasts, but failed with other vectors. In the first targeting, the efficiency was 10 times greater in fetal v. adult fibroblasts. The derivation of neural precursor cell lines from cloned blastocysts is a useful procedure to have sufficient material for molecular analysis without the need of rejuvenating the cell through the production of a fetus. None of the vectors used for the targeting of the second allele was successful.

308 INFLUENCE OFA MATRIX ATTACHMENT REGION ON THE EXPRESSION OF BICISTRONIC VECTORS TRANSFECTED IN MAMMALIAN CELLS CULTURED IN VITRO

We investigated the effect of the 52 MAR (matrix attachment region) sequence of chicken lysozyme gene as a possible insulator for the expression of our transgenes in somatic cells to be used for nuclear transfer. With the preliminary purpose to demonstrate a possible positive effect (position or copy number) on the long-term combined expression during in vitro culture, we have created a bicistronic ubiquitous expression vector with (MAR+) or without (MAR–) MAR. The main structure of our constructs is composed of the pCAGGS promoter driving the expression of a reporter gene (enhanced green fluorescent protein, EGFP) followed by a loxable selection cassette (loxP-PGKneo). The MAR region was inserted before the selection cassette. After KpnI digestion, the resulting linearized vectors were purified and subsequently used to transfect adult porcine fibroblast cell lines using the Nucleofector system (Amaxa, Cologne, Germany). Fibroblasts were cultured in DMEM/M199 medium (1:1) + 10% FCS supplemented with 5 ng mL–1 of basic fibroblast growth factor (bFGF). In every experiment, 1 � 106 cells were transfected with 2.5 µg of linearized plasmid and selected for 3 weeks with medium supplemented with 400 µg mL–1 of Geneticin (G418 sulfate, Calbiochem, La Jolla, CA). On Day 8 of G418 selection, we analyzed 150 colonies for each treatment, using fluorescence microscopy with fluorescein isothiocyanate filters. Colonies were classified according to size (large) and cell morphology (small cells without signs of aging). In addition, colonies were classified for uniform GFP expression (uniform), patchy GFP expression (variegated), and no GFP expression (negative). Resistant colonies derived from MAR+ and MAR– vectors, respectively, had 36 (24%), 42 (28%), and 56 (37%) v. 79 (53%), 58 (39%), and 29 (19%) uniform, variegated, and negative GFP. Differences were significant for variegated and negative in MAR+ v. MAR– (chi square, P < 0.05). Thirty-six MAR+ and 42 MAR– colonies uniformly expressing GFP were transferred to 24-well plates and subjected to G418 selection until Day 22, when 7 MAR+ and 15 MAR– clones were still growing in culture. Four of seven MAR+ (57%) and 7/15 MAR– (47%) uniformly expressed high levels of GFP. In conclusion, we found that significantly fewer colonies expressed GFP with the MAR+ vector; however, within the GFP-expressing clones, expression was more uniform. Therefore, we did not find a beneficial effect of MAR sequences on expression in somatic cells during in vitro culture; however, further work is needed to investigate their effect after nuclear transfer and/or on the next generation of cloned transgenic animals.

52 PRELIMINARY DATA ON PIG-BOVINE INTERSPECIES NUCLEAR TRANSFER EMBRYO DEVELOPMENT

Interspecies nuclear transfer (NT) is a very important tool for study of nuclear–cytoplasm interactions and somatic cell nucleus reprogramming. We constructed, by means of a zona-free method, NT embryos using bovine (Bo) or porcine (Po) oocytes matured in vitro and bovine fetal fibroblasts (BFF), pig adult fibroblasts (PAF), and pig fetal (PFF) green fluorescent protein (GFP)-positive fibroblasts. Constructs were fused by a double pulse of DC 1.2 kV/cm for 30 µs. At 3–4 h post-fusion, embryos with Bo were activated by 5 µM ionomycin for 4 min and incubated in 2 mM 6-DMAP in SOFaa for 4 h, whereas embryos with Po were activated by a double pulse of DC 1.2 kV/cm for 30 µs in the fusion medium with 1 mM Ca++ and incubated in SOFaa containing 5 µg/mL cytochalasin B in for 4 h. Embryos were cultured in SOFaa in 5% CO2, 5% O2 at 38.5°C. The NT embryo development and GFP expression (D7) were checked. Our results (Table 1) showed that the blastocyst rate of control bovine and pig embryos was 74% and from 20 to 44%, respectively. ‘Pig fibroblasts into Bo’ embryos were arrested at the 8–21-cell stage while ‘BFF into Po’ embryos were arrested at the 4-cell stage. About 84% of ‘PFF GFP+ into Bo’ NT embryos started to express GFP, but only 3.2% (3/95) of the embryos were able to progress through the 16-cell stage suggesting insufficient embryonic genome activation. Overall significantly more ‘Pig fibroblast into Bo’ embryos were able to progress through the 4-cell stage pig developmental block than normal pig NT embryos (57.8 ± 3.5% vs. 47.1 ± 1.3%; t-test, P = 0.02). This study shows that early embryo development is driven by recipient cytoplasm up to the stage when genome activation should occur. The arrest of interspecies NT embryos at the stage of embryonic genome activation suggests that this developmental step is impaired. Table 1. Interspecies NT embryo development This work was funded by grant ISS CS 11 and ESF.

Metastatic lymphadenopathy from ENT carcinoma: role of diagnostic imaging

Problems concerning the use of different imaging modalities in N staging of the neck are dealt with. The peculiar features, findings, sensitivity, specificity and diagnostic accuracy of each modality in the diagnosis of nature of cervical lymphadenopathy are described, as reported in most recent reports of literature, and according to the personal experience. CT/MRI criteria commonly used to establish whether a lymph node is metastatic or benign/reactive are related to the size, morphology, density (CT), signal intensity (MRI), evidence of central necrosis and extracapsular spread. Color Doppler US is a reliable method in the diagnosis of cervical metastatic lymphadenopathy even if no parameter is highly predictive; the combination of different findings, especially cortical thickening and structural inhomogeneity with thin, compressed, displaced or non visualized hilum makes the procedure significantly sensitive and specific. Intranodal hilar vascularization on color Doppler, with high resistance arterial flow (PI > 1.5), enhances the predictive value of findings of bi-dimensional sonography. Extracapsular spread impacts on survival as well as on the number of recurrences, which increases in patients with extracapsular spread; the disease-free interval is less in these patients. The identification and definition of extracapsular spread is based on some CT/MRI criteria as: 1) lymph nodes with spiky, irregular margins; 2) loss of adipose cleavage planes around the node and thickening of adjacent fascia; 3) apparent invasion of an adjacent structures or muscles. Similarly to CT/MR, sonographic findings of extracapsular spread can be: 1) blurred margins and irregular contours; 2) invasion of an adjacent structure or muscle.

Taking a family history in cancer patients with a simple questionnaire

A one-page family history questionnaire was validated in two European areas covered by population-based cancer registries. Information on malignant tumor occurrence in first degree relatives was collected from 193 cancer patients in Trieste, Italy and from 64 in Basel, Switzerland. They were then compared with the corresponding data stored in the registries' files. The sensitivity of the questionnaire was 85% (Trieste) and 74% (Basel), the specificity was 97% in both studies and the overall accuracy 95% (Trieste) and 94% (Basel). The questionnaire is recommended for use in different geographical areas covered by population based registries for comparative analyses of cancer related family histories.

Cancer risk in first-degree relatives of children with malignant tumours (Province of Trieste, Italy)

We conducted a population-based cohort study in the province of Trieste, Italy, to assess whether the first-degree relatives of children with malignancies had an increased risk of cancer compared with the general population. We examined cancers occurring in all first-degree relatives of children who experienced malignancies under the age of 15 years between 1971 and 1993 (probands). A cohort of the 394 relatives of the 125 probands contributed 7,939 person-years of observation. Among the relatives as a whole, we found a statistically significant increased risk of developing all malignancies except non-melanoma skin carcinoma (21 observed relatives with cancer and 12.46 expected, for a standardized incidence ratio [SIR] of 1.69), of developing breast cancer (SIR = 3.09) and of developing haemolymphatic system neoplasms (SIR = 4.03). This was mainly due to the excess cancer risk in the relatives of probands with intracranial tumours, who showed a significant 3.1-fold risk for developing all cancers but non-melanoma skin tumours. Our findings and the previously reported steep rise in the incidence of childhood brain tumours in our area may imply that not only genetic factors but also shared environmental agents might be involved in the observed aggregation of cancer in the families of probands with intracranial tumours.

[Malignant tumors in children living in the province of Trieste, 1972-1993: descriptive epidemiology and the quality of diagnostic-therapeutic services]

The study objectives were: 1) to analyse the incidence and death rates from cancer among children aged 0-14 years resident in the north-eastern Italian province of Trieste between 1972-1993, using data from the population-based Trieste Cancer Registry; 2) to evaluate the local diagnostic facilities by analysing the accuracy of histological diagnoses, the causes of delay in the diagnosis, and the interval between onset of symptoms and diagnosis of cancer; 3) to calculate the proportion of patients treated following the most effective therapy protocols known at the time of the tumour detection, and to compute the actuarial five-year survival rates since diagnosis. We recorded 123 new cases of cancer (93% microscopically verified) corresponding to a rate, age-standardized to the world population, of 161.9 (standard error [SE] = 15.1) per million child-years. The most common diagnostic group was that of primary brain tumours: 40 cases, rate = 51.0 (SE = 8.4). In 102 cases the diagnosis was made at hospitals in the province of Trieste, with a median time of seven days (25th-75th percentile = 1-16) between admission and diagnosis. In 37 cases the length of the interval between the advancing of the diagnostic hypothesis of cancer and the microscopic diagnosis ranged from eight to 57 days: 20% of the interval was spent in the identification of the lesion, 50% elapsed between the identification and the biopsy, and 30% was spent in performing the microscopic diagnosis. Out of 123 cases, 30 were partly treated or completely treated at centres not located in our province, i.e., at seven different Italian hospitals (14 cases), nine European hospitals (15 cases), and at one North-American centre (one case). The 40 children with brain tumours were spread among 12 institutions. The five-year survival rate increased from 52.4% (SE = 6.3) for the 63 children with cancers diagnosed in 1972-1981 to 62.5% (SE = 7.0) for the 48 with malignancies detected in 1982-1990.