Normalisation to Blood Activity Is Required for the Accurate Quantification of Na/I Symporter Ectopic Expression by SPECT/CT in Individual Subjects

The utilisation of the Na/I symporter (NIS) and associated radiotracers as a reporter system for imaging gene expression is now reaching the clinical setting in cancer gene therapy applications. However, a formal assessment of the methodology in terms of normalisation of the data still remains to be performed, particularly in the context of the assessment of activities in individual subjects in longitudinal studies. In this context, we administered to mice a recombinant, replication-incompetent adenovirus encoding rat NIS, or a human colorectal carcinoma cell line (HT29) encoding mouse NIS. We used 99mTc pertechnetate as a radiotracer for SPECT/CT imaging to determine the pattern of ectopic NIS expression in longitudinal kinetic studies. Some animals of the cohort were culled and NIS expression was measured by quantitative RT-PCR and immunohistochemistry. The radioactive content of some liver biopsies was also measured ex vivo. Our results show that in longitudinal studies involving datasets taken from individual mice, the presentation of non-normalised data (activity expressed as %ID/g or %ID/cc) leads to ‘noisy’, and sometimes incoherent, results. This variability is due to the fact that the blood pertechnetate concentration can vary up to three-fold from day to day. Normalisation of these data with blood activities corrects for these inconsistencies. We advocate that, blood pertechnetate activity should be determined and used to normalise the activity measured in the organ/region of interest that expresses NIS ectopically. Considering that NIS imaging has already reached the clinical setting in the context of cancer gene therapy, this normalisation may be essential in order to obtain accurate and predictive information in future longitudinal clinical studies in biotherapy

Noninvasive imaging of the transcriptional activities of human telomerase promoter fragments in mice

We have assessed the feasibility of positron emission tomography (PET) and ex vivo gamma-counting to measure the pattern of expression of telomerase promoter fragments in vivo. Promoter fragments from either the RNA [human telomerase RNA (hTR)] or the catalytic components [human telomerase reverse transcriptase (hTERT)] of the telomerase genes were used to drive the expression of the sodium iodide symporter PET reporter gene in recombinant adenoviruses. Both promoter fragments provided cancer-selective expression that could be visualized and quantitated by PET. The transcriptional activity of the hTR promoter was found to be consistently stronger than that of the hTERT promoter. Both promoters appear therefore to be good candidates for safe use in gene therapy, and PET imaging can be used to assess the selectivity of promoters in vivo. Given that this methodology is directly scalable to humans, imaging gene expression using the sodium iodide symporter PET reporter gene could be applied to measure telomerase promoter activity in humans

NSL monitoring report for 2022. State of affairs of the National Air Quality Cooperation Programme

In het Nationaal Samenwerkingsprogramma Luchtkwaliteit ( NSL (Nationaal Samenwerkingsprogramma Luchtkwaliteit)) werken de overheden sinds 2009 samen om de luchtkwaliteit te verbeteren. De monitor van het NSL is onder andere bedoeld om te kijken of Nederland de Europese grenswaarden voor luchtkwaliteit haalt. En als dat niet zo is, of extra maatregelen nodig zijn om ze toch zo snel mogelijk te halen. Het RIVM rapporteert elk jaar over stikstofdioxiden en fijnstof in de lucht. Uit de rapportage 2022 blijkt dat de luchtkwaliteit in 2021 bijna hetzelfde is als in 2020. Ook in 2021 voldoet Nederland voor wegverkeer aan de Europese grenswaarden voor stikstofdioxide. Voor fijnstof is dat ook het geval langs de wegen in Nederland, met uitzondering van een klein stuk weg van 200 meter bij Velsen. Op enkele woonlocaties in gebieden met intensieve veehouderijen zijn de grenswaarden van fijnstof in 2021 nog steeds overschreden; iets meer dan in 2020. De lage concentraties voor stikstofdioxide en fijnstof in 2020 en 2021 komen onder andere door de maatregelen die zijn genomen tegen de verspreiding van het coronavirus. Er was daardoor binnen en buiten Nederland minder verkeer en economische activiteit, en dus minder uitstoot. Dit effect is waarschijnlijk tijdelijk. In 2021 zijn de concentraties wel iets hoger dan in 2020, waardoor er iets meer overschrijdingen berekend zijn. Dit komt mogelijk doordat er in 2021 meer verkeer en meer economische activiteit waren dan in 2020. Het is niet duidelijk of het effect helemaal verdwijnt als de coronamaatregelen worden opgeheven. De verwachting is wel dat de luchtkwaliteit de komende jaren verder verbetert. Dat komt doordat verkeer, industrie en veehouderijen naar verwachting minder stikstofdioxide en fijnstof zullen uitstoten. Zo worden bijvoorbeeld elk jaar oudere auto’s vervangen door nieuwere die minder stikstofoxiden uitstoten. In 2030 worden de Europese grenswaarden die nu voor stikstofdioxiden en fijnstof gelden naar verwachting niet meer overschreden. Tegen die tijd zijn er, naar verwachting, nog meer maatregelen genomen voor een nog betere luchtkwaliteit en voor het klimaat. Een ander beeld ontstaat als wordt gerekend met de nieuwe, strengere advieswaarden van de WHO (World Health Organization) uit 2021. Dan zijn veel inwoners in 2021 blootgesteld geweest aan concentraties boven de advieswaarden. Deze waarden zijn nu niet in Nederlandse wetgeving opgenomen.Since 2009, all tiers of government have been working together to improve air quality through the National Air Quality Cooperation Programme (Nationaal Samenwerkingsprogramma Luchtkwaliteit, NSL). The NSL monitoring report is intended, among other things, to ensure that the Netherlands meets the European limit values for air quality and, in case these are not met, whether additional measures are needed to meet them as quickly as possible. Each year, RIVM reports on nitrogen dioxides and particulate matter in the air. The 2022 report shows that the air quality in 2021 was almost the same as in 2020. In 2021, the Netherlands once again met the European limit values for nitrogen dioxide emitted by road traffic. This was also the case for particulate matter along the roads, with the exception of a small 200-metre stretch of road near Velsen. At some residential locations in areas with intensive livestock farming, the limit values for particulate matter were still exceeded in 2021. This occurred slightly more often than in 2020. The low concentrations of nitrogen dioxide and particulate matter in 2020 and 2021 were partly due to the measures taken to prevent the spread of the coronavirus. As a result, there was less traffic and less economic activity both inside and outside the Netherlands, leading to fewer emissions. This effect is likely to be temporary. In 2021, the concentrations were slightly higher than in 2020, to the extent that slightly more exceedances were calculated. This may be because there was more traffic and more economic activity in 2021 than in 2020. It is not clear whether the effect will disappear completely once the coronavirus measures are lifted. Air quality is expected to improve further in the coming years because traffic, industry and livestock farming are expected to emit less nitrogen dioxide and particulate matter. For example, older cars are replaced by newer ones that emit fewer nitrogen oxides every year. In 2030, the European limit values that now apply for nitrogen dioxide and particulate matter are no longer expected to be exceeded. By then, it is expected that even more measures will have been taken to improve air quality and mitigate climate change. A different picture arises if you take into account the new, stricter air quality guidelines of the WHO from 2021. In that scenario, many residents were exposed to concentrations above the recommended levels in 2021. These guidelines are currently not included in Dutch legislation