IRMM-1000a and IRMM-1000b: uranium reference materials certified for the production date based on the 230Th/234U radiochronometer. Part II: certification

The IRMM-1000a and IRMM-1000b uranium reference materials, of 20 and 50 mg uranium, respectively, were produced by the European Commission Joint Research Centre's Institute for Reference Materials and Measurements (EC-JRC-IRMM) in collaboration with the Institute for Transuranium Elements (EC-JRC-ITU). They are novel uranium reference materials certified for the production date based on the 230Th/234U radiochronometer, i.e. the date of the last chemical separation of these two radionuclides. The certified reference value and its uncertainty, homogeneity and stability of the material were established in accordance with the ISO Guide 34:2009 and the 'Guide to the Expression of Uncertainty in Measurement'.

Dural ectasia in Marfan's syndrome: magnetic resonance imaging appearances and anaesthetic experience of three deliveries

Neuraxial anaesthetic techniques are considered useful to minimise haemodynamic stress during labour. In Marfan's syndrome, connective tissue abnormalities not only affect the thoracic aorta but also predispose to dural ectasia. A dural ectatic sac may cause difficulties with neuraxial analgesia and anaesthesia. We discuss magnetic resonance imaging appearances and anaesthetic experience of three deliveries in a parturient with stable echocardiographic findings. We consider that epidural analgesia and anaesthesia are a safe and pragmatic solution for labour and delivery. Lumbo-sacral magnetic resonance imaging at presentation will define dural ectasia and assist in management.

Investigation of the isotopic composition of lead and of trace elements concentrations in natural uranium materials as a signature in nuclear forensics

Lead is contained as trace element in uranium ores and propagates throughout the production process to intermediate products like yellow cake or uranium oxide. The lead isotopes in such material originate from two sources: natural lead and radiogenic lead. The variability of the isotopic composition of lead in ores and yellow cakes was studied and the applicability of this parameter for nuclear forensic investigations was investigated. Furthermore, the chemical impurities contained in these materials were measured in order to identify characteristic differences between materials from different mines. For the samples investigated, it could be shown, that the lead isotopic composition varies largely from mine to mine and it may be used as one of the parameters to distinguish between materials of different origins. Some of the chemical impurities show a similar pattern and support the conclusions drawn from the lead isotope data.

Separation of248Cm from a252Cf neutron source for production of Cm targets

The separation of milligram amounts of248Cm from252Cf is presented. Essentially isotopically pure248Cm was obtained from an "old"252Cf neutron source by acid leaching. Curium was separated from californium in a cation exchange column combining two different eluents: α-HMBA at pH 4.0 for Cf, and α-HIBA at pH 4.8 for Cm. The method was first tested using Sm and Gd as actinide analogues. Excellent separation was obtained, yielding 12.6 mg Cm (11.9 mg248Cm) free from Cf (250Cf < 1.3×10-2ng and252Cf < 4.2×10-3ng).

Structurally diverse peroxisome proliferator-activated receptor agonists induce apoptosis in human uro-epithelial cells by a receptor-independent mechanism involving store-operated calcium channels

OBJECTIVES

Peroxisome proliferator-activated receptors (PPARs) are implicated in epithelial cell proliferation and differentiation, but investigation has been confounded by potential off-target effects of some synthetic PPAR ligands. Our aim was to determine mechanisms underlying the pro-apoptotic effect of synthetic PPAR agonists in normal human bladder uro-epithelial (urothelial) cells and to reconcile this with the role of PPARs in urothelial cytodifferentiation.

MATERIALS AND METHODS

Normal human urothelial (NHU) cells were grown as non-immortal lines in vitro and exposed to structurally diverse agonists ciglitazone, troglitazone, rosiglitazone (PPARgamma), ragaglitazar (PPARalpha/gamma), fenofibrate (PPARalpha) and L165041 (PPARbeta/delta).

RESULTS

NHU cells underwent apoptosis following acute exposure to ciglitazone, troglitazone or ragaglitazar, but not fenofibrate, L165041 or rosiglitazone, and this was independent of ERK or p38 MAP-kinase activation. Pro-apoptotic agonists induced sustained increases in intracellular calcium, whereas removal of extracellular calcium altered the kinetics of ciglitazone-mediated calcium release from sustained to transient. Cell death was accompanied by plasma-membrane disruption, loss of mitochondrial membrane-potential and caspase-9/caspase-3 activation. PPARgamma-mediated apoptosis was unaffected following pre-treatment with PPARgamma antagonist T0070907 and was strongly attenuated by store-operated calcium channel (SOC) inhibitors 2-APB and SKF-96365.

CONCLUSIONS

Our results provide a mechanistic basis for the ability of some PPAR agonists to induce death in NHU cells and demonstrate that apoptosis is mediated via PPAR-independent mechanisms, involving intracellular calcium changes, activation of SOCs and induction of the mitochondrial apoptotic pathway.

Assessment of the exposure of islanders to ash from the Soufriere Hills volcano, Montserrat, British West Indies

BACKGROUND AND AIMS

The Soufriere Hills volcano, Montserrat, has been erupting since July 1995 and volcanic ash has fallen on the island throughout most of the eruption. The ash contains substantial quantities of respirable particles and unusually large amounts (15-20%) of the crystalline silica mineral, cristobalite. The purpose of the surveys described here, undertaken between December 1996 and April 2000, was to determine levels of personal exposure of islanders to volcanic ash and cristobalite in order to inform advice on the associated risks to health and the measures required to reduce exposure.

METHODS

Surveys of personal exposure to respirable dust and cristobalite were undertaken using cyclone samplers. In addition, direct reading instruments (DUSTTRAK) were used to monitor ambient air concentrations of PM(10) at fixed sites and also to provide information about exposures to airborne particles associated with selected activities.

RESULTS

Environmental concentrations of airborne ash have been greatest in the areas where the most ash has been deposited and during dry weather. Individual exposure to airborne ash was related to occupation, with the highest exposures among gardeners, cleaners, roadworkers, and police at roadside checkpoints. During 1997 many of these individuals were exposed to concentrations of cristobalite that exceeded the ACGIH recommended occupational exposure limit. Since the population became confined to the north of the island in October 1997, even those in relatively dusty occupations have received exposures to cristobalite well below this limit.

CONCLUSIONS

Most of the 4500 people who have remained on island since the eruption began have not been exposed to sufficiently high concentrations of airborne dust for long enough to be at risk of developing silicosis. However, more than a dozen individuals continued to experience frequent high occupational exposures to volcanic ash, some of whom may have had sufficient exposure to crystalline silica to be at risk of developing mild silicosis. If volcanic activity were to deposit further ash over the occupied areas of the island during the coming years, the risks of silicosis will become more substantial.

Monitoring of airborne particulate matter during the eruption of Soufrière Hills Volcano, Montserrat

A programme of air quality monitoring was devised to investigate concentrations and behaviour of repirable ash in the air on Montserrat. Sampling strategies used were short environmental tests, occupational tests, and continuous environmental monitoring in periods of both high and low volcanic activity. The results obtained between September 1996 and July 1999 allow comparison of the contributions made to airborne particles by different eruptive styles. Vulcanian explosions and ash-venting increased average background concentrations (c.30 µg m -3) of airbrne particles (≤10 µm in diameter) by up to a factor of ten. Large dome collapses released large amounts of ash into the atmosphere in an extremely sort time and airborne particle concentrations reached more than 600 µg m-3. Aggregates of ash particles broke up on impact wth the gournd and ash re-suspension by wind caused airborne particle concentrations of approximately 250 µg m-3. which were sometimes significantly higher than those caused by tephra fallout. Airborne particle concentration decreased with distance from the ash source, and wind an drain effectively removed ash from the atmosphere. Generally, airborne particle concentrations in inhabited areas of Montserrat remained low, even during elevated volcanic activity, when volcanic products were carried away by winds

Vertically transmitted HIV infection in the British Isles

OBJECTIVE

To describe the epidemiology of vertically acquired HIV infection in the British Isles, the level of underreporting, the vertical transmission rate, and clinical spectrum of paediatric AIDS.

DESIGN

Confidential, linked registers based on reporting from obstetricians and paediatricians; anonymous unlinked neonatal HIV serosurveys.

SETTING

British Isles.

SUBJECTS

Children born to mothers with HIV infection.

MAIN OUTCOME MEASURES

Trends in HIV infection and vertical transmission rate.

RESULTS

In Scotland and the Irish Republic, where most maternal HIV infection is related to drug misuse, the annual number of reports of children born to infected mothers has fallen since 1989. In England and Wales nearly half of maternal infections have been acquired overseas, and the number of children born to these women, and to women who became infected in Britain, is increasing. In south east England the proportion of live births to women whose infection was identified before delivery was only 17% (50/287), compared with 68% (26/38) in Scotland. The vertical transmission rate was 13.7% (23/168), and 23% of infected children developed AIDS in the first year of life. 41% (38/92) of children born to infected mothers who were ascertained after delivery were breast fed, compared with 5% (12/236) of those ascertained before delivery.

CONCLUSIONS

The incidence of vertically transmitted HIV infection is increasing in England and Wales. More extensive antenatal testing would enable infected women to be counselled against breast feeding, which could prevent a substantial proportion of vertical transmission in some areas, and would increase opportunities for early diagnosis and treatment of infected children.