The significance of molecular studies in the long-term follow-up of children with beckwith- wiedemann syndrome

Beckwith-Wiedemann syndrome (BWS) is a congenital disorder of imprinting caused by epimutations and mutations affecting two imprinted loci on chromosome 11p15. Its clinical features are heterogeneous, including macrosomia, macroglossia, hemihyperplasia, abdominal wall defects, neonatal hypoglycemia, and increased risk of embryonal tumors such as Wilms tumor, adrenocortical carcinoma, hepatoblastoma, and neuroblastoma. The molecular and clinical heterogeneity of BWS makes the diagnosis challenging, but essential, since different etiologies of BWS have different clinical prognoses - most crucially, patients with gain of maternal methylation at imprinting control region type 1 (ICR1) are at significant risk of Wilms tumor or hepatoblastoma. We present three cases of BWS with different symptomatology and two different molecular diagnoses. The authors emphasize the importance of molecular studies in the long-term follow-up of children with BWS, including refinement of phenotype-genotype correlation and its connection with optimal management and tumor surveillance.

Evaluation of critical body residue data for acute narcosis in aquatic organisms

The Environmental Residue Effects Database was evaluated to identify critical body residues of organic chemicals causing acute baseline neutral narcosis in aquatic organisms. Over 15 000 records for >400 chemicals were evaluated. Mean molar critical body residues in the final data set of 161 records for 29 chemicals were within published ranges but varied within and among chemicals and species (~3 orders of magnitude), and lipid normalization did not consistently decrease variability. All 29 chemicals can act as baseline neutral narcotics, but chemicals and/or their metabolites may also act by nonnarcotic modes of action. Specifically, nonnarcotic toxicity of polycyclic aromatic hydrocarbons and/or their biotransformation derivatives may be a significant source of variability. Complete testing of the narcosis-critical body residue hypothesis was confounded by data gaps for key toxicity modifying factors such as metabolite formation/toxicity, lipid content/composition, other modes of toxic action, and lack of steady-state status. Such problems impede determination of the precise, accurate toxicity estimates necessary for sound toxicological comparisons. Thus, neither the data nor the chemicals in the final data set should be considered definitive. Changes to testing designs and methods are necessary to improve data collection and critical body residue interpretation for hazard and risk assessment. Each of the toxicity metrics discussed-wet weight and lipid weight critical body residues, volume fraction in organism lipid, and chemical activity-has advantages, but all are subject to the same toxicity modifying factors.

Livestock weights in response to three whole-farmlet management systems

This paper reports changes in livestock weights recorded in a whole-farmlet experiment, which aimed to examine the profitability and sustainability of three different pasture and grazing management strategies. The assessment of liveweights was considered a key component of measuring the integrated effects of the farmlet-scale treatments. The three farmlets comprised a typical management regime, which employed flexible rotational grazing over eight paddocks with moderate soil fertility (farmlet B), a system based on the same grazing management and paddock number but with higher levels of sown pasture and soil fertility (farmlet A) and a farmlet with moderate soil fertility and intensive rotational grazing over 37 paddocks (farmlet C). Early in the experimental period, there were no significant differences between farmlets in the liveweight of any class of livestock. However, from the second year onwards, as the pasture renovation, soil fertility and grazing management treatments took effect, differences in liveweight between farmlets became more apparent and significant. The stocking rate, which was treated as an emergent property of each farmlet, reached a maximum annual average value after 5 years of 12.6, 8.5 and 7.7 dry sheep equivalents (dse)/ha on farmlets A, B and C representing 84, 113 and 51% of their respective target stocking rates which were 15, 7.5 and 15 dse/ha. The liveweights of ewes, both before joining and during pregnancy, varied with year and farmlet with those on farmlets A and B tending to be significantly heavier than those on farmlet C. From 2003 to 2006, liveweights were significantly (P < 0.001) affected by a wide array of factors and their interactions including: date, ewe age, green digestible herbage, legume herbage mass, proportion of farmlet grazed, stocking rate and level of supplementary feeding. The weights of lambs/weaners/hoggets, both pre- and post-weaning, were at times also higher on farmlets A and B compared with those on farmlet C and were affected by a similar range of factors to those which affected ewe weights. Similar relative differences also applied to the liveweights of the other livestock run on the farmlets, namely wethers and non-reproductive cattle. The results suggest that stocking rate was able to be increased towards the higher target of farmlet A due to the higher level of pasture renovation and soil fertility on that farmlet, which led to high liveweights per head as well as the higher stocking rate. However, as the stocking rate increased on farmlet A, the differences between farmlets in liveweight per head diminished and the need for supplementary feeding increased. In contrast, the intensive rotational grazing practised on farmlet C did not allow the farmlet to increase its stocking rate towards its higher target. It appears that the higher proportion of each of farmlets A and B grazed at any one time allowed all classes of livestock to reach higher liveweights per head than on farmlet C, due presumably to the greater proportion of those two farmlets grazed at any one time.

Search for neutrinoless double-beta decay in 136Xe with EXO-200

We report on a search for neutrinoless double-beta decay of 136Xe with EXO-200. No signal is observed for an exposure of 32.5 kg yr, with a background of ∼1.5×10(-3)  kg(-1) yr(-1)  keV(-1) in the ±1σ region of interest. This sets a lower limit on the half-life of the neutrinoless double-beta decay T(1/2)(0νββ)(136Xe)>1.6×10(25)  yr (90% C.L.), corresponding to effective Majorana masses of less than 140-380 meV, depending on the matrix element calculation.

Familial occurrence of neonatal diabetes with duplications in chromosome 6q24: treatment with sulfonylurea and 40-yr follow-up

We present a Norwegian family, followed since 1967, with a chromosome 6q24 duplication in two siblings with neonatal diabetes, in their non-diabetic father, and in a female (third generation) with adult-onset diabetes. The parents (first generation) were healthy and non-consanguineous. After a miscarriage, the couple had two infants with birth weights of 1780 and 1620 g, respectively, both of whom died on their second day of life. Patient I (male, weight 1840 g at term) had a blood glucose level of 33 mmol/L on day 6. He was treated with insulin for 3 months. In adult life he had permanent diabetes, treated with oral hypoglycemic agents. At 43 yr of age, there were no diabetic late complications. Patient II (female, birth weight 1440 g at term) had an increasing blood glucose of 55 mmol/L on day 13. She received insulin treatment for 12.5 months. Subsequently, she was successfully treated with sulfonylurea (tolbutamide) for 10 yr. At 11 yr of age, insulin was again considered necessary. At 40 yr of age, no diabetic late complications were detected. Patient III had a birth weight of 2630 g at term and no diabetic symptoms as a neonate. She had insulin-requiring diabetes from age 19. We conclude that (i) neonatal diabetes with chromosome 6q24 duplications may become a permanent disease in adult life; (ii) this chromosome anomaly may also be associated with adult-onset diabetes; (iii) sulfonylurea treatment may be attempted, and (iv) late diabetic complications may be absent, even after more than 40 yr.

Observation of two-neutrino double-beta decay in 136Xe with the EXO-200 detector

We report the observation of two-neutrino double-beta decay in (136)Xe with T(1/2) = 2.11 ± 0.04(stat) ± 0.21(syst) × 10(21) yr. This second-order process, predicted by the standard model, has been observed for several nuclei but not for (136)Xe. The observed decay rate provides new input to matrix element calculations and to the search for the more interesting neutrinoless double-beta decay, the most sensitive probe for the existence of Majorana particles and the measurement of the neutrino mass scale.

Nasal reconstruction

The nose is the central feature that defines one's face. Acquired nasal defects arise from a variety of pathologic and traumatic etiologies and reconstructive surgeons may be called upon to restore form and function when the nose has been altered in some way. Nasal reconstruction is one of the most challenging and rewarding procedures performed by the plastic surgeon. A detailed knowledge of the anatomy of the nose - the lining, support and cover - is essential in designing the reconstructive effort. Surgical planning involves, first, identifying the extent of the acquired defect, followed by the application of an intricate knowledge of the tissues that will provide a functional and aesthetically pleasing yet durable reconstruction. In this article, the reader will find a description of the clinically important anatomic features of the nose as they relate to various reconstructive procedures aimed at restoring nasal appearance and maintaining airway patency.

A magnetically driven piston pump for ultra-clean applications

A magnetically driven piston pump for xenon gas recirculation is presented. The pump is designed to satisfy extreme purity and containment requirements, as is appropriate for the recirculation of isotopically enriched xenon through the purification system and large liquid xenon time projection chamber of EXO-200. The pump, using sprung polymer gaskets, is capable of pumping more than 16 standard liters per minute of xenon gas with 750 Torr differential pressure.

No evidence for pathogenic variants or maternal effect of ZFP57 as the cause of Beckwith-Wiedemann Syndrome

Beckwith-Wiedemann syndrome (BWS) is an overgrowth syndrome, which, in 50-60% of sporadic cases, is caused by hypomethylation of KCNQ1OT1 differentially methylated region (DMR) at chromosome 11p15.5. The underlying defect of this hypomethylation is largely unknown. Recently, recessive mutations of the ZFP57 gene were reported in patients with transient neonatal diabetes mellitus type 1, showing hypomethylation at multiple imprinted loci, including KCNQ1OT1 DMR in some. The aim of our study was to determine whether ZFP57 alterations were a genetic cause of the hypomethylation at KCNQ1OT1 DMR in patients with BWS. We sequenced ZFP57 in 27 BWS probands and in 23 available mothers to test for a maternal effect. We identified three novel, presumably benign sequence variants in ZFP57; thus, we found no evidence for ZFP57 alterations as a major cause in sporadic BWS cases.

A simple radionuclide-driven single-ion source

We describe a source capable of producing single barium ions through nuclear recoils in radioactive decay. The source is fabricated by electroplating (148)Gd onto a silicon α-particle detector and vapor depositing a layer of BaF(2) over it. (144)Sm recoils from the alpha decay of (148)Gd are used to dislodge Ba(+) ions from the BaF(2) layer and emit them in the surrounding environment. The simultaneous detection of an α particle in the substrate detector allows for tagging of the nuclear decay and of the Ba(+) emission. The source is simple, durable, and can be manipulated and used in different environments. We discuss the fabrication process, which can be easily adapted to emit most other chemical species, and the performance of the source.

The physicochemical basis of QSARs for baseline toxicity

The physico-chemical properties relevant to the equilibrium partitioning (bioconcentration) of chemicals between organisms and their respired media of water and air are reviewed and illustrated for chemicals that range in hydrophobicity. Relationships are then explored between freely dissolved external concentrations such as LC50s and chemical properties for one important toxicity mechanism, namely baseline toxicity or narcosis. The 'activity hypothesis' proposed by Ferguson in 1939 provides a coherent and compelling explanation for baseline toxicity of chemicals in both water- and air-respiring organisms, as well as a reference point for identifying more specific toxicity pathways. From inhalation studies with fish and rodents, narcosis is shown to occur at a chemical activity exceeding approximately 0.01 and there is no evidence of narcosis at activities less than 0.001. The activity hypothesis provides a framework for directly comparing the toxic potency of chemicals in both air- and water-breathing animals. The activity hypothesis is shown to be consistent with the critical body residue concept, but it has the advantage of avoiding the confounding effect of lipid content of the test organism. It also provides a theoretically sound basis for assessing the baseline toxicity of mixtures. It is suggested that since activity is readily calculated from fugacity, observed or predicted environmental abiotic and biotic fugacities can be used to evaluate the potential for baseline toxicity. Further, models employing fugacity or activity can be used to improve the experimental design of bioassays, thus possibly reducing unnecessary animal testing.

Concentrations of decabromodiphenyl ether in air from Southern Ontario: implications for particle-bound transport

Atmospheric concentrations are reported for the main component of the brominated flame retardant decaBDE (BDE-209) in air samples collected from Southern Ontario for the period January 23-June 06, 2002. Levels ranged from below detection to 105pgm(-3) with virtually all of BDE-209 being trapped by the filter and thus deduced to be sorbed to aerosol particles. Thus, it is likely that the long-range atmospheric transport (LRAT) of BDE-209 is controlled by the transport characteristics of the aerosols. This conclusion that BDE-209 does not have the same potential for LRAT as other more volatile PBDEs is subject to possible complications arising from the uncertainties about the LRAT potential of aerosols.

Passive and active air samplers as complementary methods for investigating persistent organic pollutants in the Great Lakes Basin

Data obtained using passive air samplers (PAS) are compared to active high-volume air sampling data in order to assess the feasibility of the PAS as a method, complementary to active high-volume air sampling (AAS), for monitoring levels of organochlorine (OC) pesticides, polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) in the Laurentian Great Lakes. PAS were deployed at 15 of the Integrated Atmospheric Deposition Network (IADN) sites on a quarterly basis between July 2002 and June 2003, and PAS and AAS results are compared. Levels for the OC pesticides are typically highest in agricultural areas, with endosulfan I dominating air concentrations with values ranging between 40 and 1090 pg x m(-3), dieldrin values between 15 and 165 pg x m(-3), and gamma-HCH values between 13 and 100 pg x m(-3). alpha-HCH was seen to be relatively uniform across the Great Lakes Basin with values ranging between 15 and 73 pg x m(-3). Large urban centers, such as Chicago and Toronto, have the highest levels of PCBs and PBDEs that range between 400 and 1200 pg x m(-3) and 10 and 70 pg x m(-3), respectively. Comparison of the AAS and the PAS data collected during this study shows good agreement, within a factor of 2 or 3, suggesting that the two sample methods produce comparable results. It is suggested that PAS networks, while providing data that are different in nature from AAS, can provide a cost-effective and complementary approach for monitoring the spatial and temporal trends of persistent organic pollutants.