Background
The aim of this brief communication is to highlight the potential bacteriological risk linked to the processes control of radiopharmaceutical preparations made in a radiopharmacy ...laboratory. Survival rate of
Pseudomonas aeruginosa
(
ATCC: 27853
) or
Staphylococcus aureus (ATCC: 25923)
or
Staphylococcus epidermidis (ATCC: 1228)
in multidose technetium-99 m solution was studied.
Results
Depending on the nature and level of contamination by pathogenic bacteria, the lethal effect of radioactivity is not systematically observed. We found that
P. aeruginosa
was indeed affected by radioactivity. However, this was not the case for
S. epidermidis
, as the quantity of bacteria found in both solutions (radioactive and non-radioactive) was rapidly reduced, probably due to a lack of nutrients. Finally, the example of
S. aureus
is an intermediate case where we observed that high radioactivity affected the bacteria, as did the absence of nutrients in the reaction medium. The results were discussed in the light of current practices on the sterility test method, which recommends waiting for radioactivity to decay before carrying out the sterility test.
Conclusion
In terms of patient safety, the results run counter to current practice and the latest EANM recommendation of 2021 that radiopharmaceutical preparations should be decayed before sterility testing.
When predicting thunderstorms and localized severe weather events, close calls occur more frequently than direct hits. This makes it difficult for traditional verification approaches to fully ...represent forecast performance since events observed near a forecast event are counted both as misses and false alarms. Timing and location relative to the affected population are therefore two of the most important aspects of such a forecast. Verification of these aspects allows the determination of a safe distance for the user of a given severe weather alert. In this study, we propose a forecast verification measure based on the Generalized Distance Transform that is mathematically rigorous yet intuitive and user-friendly in its interpretation. The proposed measure compares the distance from a user location to an alert area against the distance from the same user location to a set of observed events. Time series for such comparisons can then be constructed, allowing evaluation of the timing error obtained from the difference between the two time series. Finally, the ‘worst overforecast’ and ‘worst underforecast’ are diagnosed in terms of relative distance.
The Registry of Adult and Paediatric Patients Treated with Cystadane® - Homocystinuria (RoCH) is a non-interventional, observational, multi-centre, post-authorization safety study that aimed to ...identify safety of betaine anhydrous (Cystadane®) in the treatment of patients with inborn errors of homocysteine metabolism (homocystinuria) in order to minimise the treatment associated risks and establish better knowledge on its clinical use. The registry included patients of all ages with homocystinuria who were treated with betaine anhydrous in conjunction with other therapies. Clinical data were collected retrospectively from 2007 to 2013, then prospectively up to February 2014. All adverse events (AEs) reported during the study were recorded. The clinical and biological status of patients was monitored at least once a year.
A total of 125 patients with homocystinuria (adults > 18 years: 50; paediatric ≤18 years: 75) were enrolled at 29 centres in France and Spain. Patients were treated with betaine anhydrous for a mean duration of 7.4 ± 4.3 years. The median total daily dose of betaine anhydrous at the first and last study visits was 6 g/day for cystathionine β-synthase (CBS)-deficient vitamin B6 responders and 9 g/day for methylenetetrahydrofolate reductase-deficient patients, while the median daily dose increased in CBS-deficient B6 non-responders (from 6 to 9 g/day) and cobalamin metabolism-defective patients (from 3 to 6 g/day) between the first and last visits. Treatment caused a mean overall reduction of 29% in plasma homocysteine levels in the study population. A total of 277 AEs were reported during the study, of which two non-serious AEs (bad taste and headache) and one serious AE (interstitial lung disease) were considered to be drug related. Overall, betaine anhydrous was well tolerated with no major safety concerns.
Data from the RoCH registry provided real-world evidence on the clinical safety and efficacy of betaine anhydrous in the management of homocystinuria in paediatric and adult patients.
Background
Despite the development of positron emission tomography (PET), single photon emission computed tomography (SPECT) still accounts for around 80% of all examinations performed in nuclear ...medicine departments. The search for new radiotracers or chelating agents for Technetium-99m is therefore still ongoing.
O-
TRENSOX and
O-
TRENOX two synthetic siderophores would be good candidates for this purpose as they are hexadentate ligands based on the very versatile and efficient 8-hydroxyquinoline chelating subunit. First, the radiolabeling of
O-
TRENOX and
O
-TRENSOX with
99m
Tc was investigated. Different parameters such as the quantity of chelating agent, type of reducing agent, pH and temperature of the reaction mixture were adjusted in order to find the best radiolabeling conditions. Then an assessment of the partition coefficient by measuring the distribution of each radiosynthesized complex between octanol and phosphate-buffered saline was realized. The complex’s charge was evaluated on three different celluloses (neutral, negatively charged P81 and positively charged DE81), and finally in vivo studies with biodistribution and SPECT imaging of
99m
TcTc-
O-
TRENOX and
99m
TcTc-
O-
TRENSOX were performed.
Results
The radiolabeling studies showed a rapid and efficient complexation of
99m
Tc with both chelating agents. Using tin pyrophosphate as the reducing agent and a minimum of 100 nmol of ligand, we obtained the
99m
TcTc-
O-
TRENOX complex with a radiochemical purity of more than 98% and the
99m
TcTc-
O-
TRENSOX complex with one above 97% at room temperature within 5 min.
99m
TcTc-
O-
TRENOX complex was lipophilic and neutral, leading to a hepatobiliary elimination in mice. On the contrary, the
99m
TcTc-
O-
TRENSOX complex was found to be hydrophilic and negatively charged. This was confirmed by a predominantly renal elimination in mice.
Conclusions
These encouraging results allow us to consider the
O-
TRENOX/
99m
Tc and
O-
TRENSOX/
99m
Tc complexes as serious candidates for SPECT imaging chelators. This study should be continued by conjugating these tris-oxine ligands to peptides or antibodies and comparing them with the other bifunctional agents used with Tc.
The distance transform (DT) (also known as distance map or distance field) is a fundamental tool of mathematical morphology. We introduce a generalized DT (GDT) that is smoother than the classical ...DT. This transform can be used to define a generalized Hausdorff metric that is shown to be more robust to noise while preserving all metric properties. It is also shown to lead to smoother level sets, allowing contour evolution without having to solve a partial differential equation. Two applications in weather analysis and forecasting demonstrate the usefulness of this proposed GDT. In particular, the dilation of sets according to the GDT allows the simplification of numerical weather forecasts and analysis into geometric objects, called MetObjects, and the generalized Hausdorff distance can be used as a forecast verification metric.
Lake of the Woods spans two geological regions: the Precambrian Shield and the Glacial Lake Agassiz Lakebed. The lake watershed’s complex topography influences wind speeds and directions. We study ...wind variability over Lake of the Woods using reanalysis data and wind observations at seven sites. A wind variability index is proposed as a measure of lake-wide spread in wind direction. Our results show that the directional variability depends on wind speeds, with higher variability at lower speeds. The wind variability also changes throughout the year; it is more pronounced in spring (Apr-Jun) and fall (Sep-Oct) and less pronounced during winter (Dec-Jan). Observed wind directions are 60% more variable than reanalysis wind, indicating a need for higher-resolution reanalysis to resolve local wind effects due to topographic changes. Based on the statistical hierarchical clustering method, our analysis shows that geographically variable wind can be grouped into three regions to represent the predominant wind directions accurately. Clustering results also suggest spatial coverage gaps in the existing meteorological observation network. We reassess the existing network and propose a new meteorological observation site in the southeast basin near Morson, Ontario. Our study is of significance for water quality management because the wind is the key driver of water circulation, transport, and mixing in the lake, and accurate wind measurements are necessary to better constrain the underpinning physical, biological, and biochemical processes in mechanistic ecological models.
Since its introduction in 2004, the structural similarity (SSIM) index has gained widespread popularity as a tool to assess the quality of images and to evaluate the performance of image processing ...algorithms and systems. There has been also a growing interest of using SSIM as an objective function in optimization problems in a variety of image processing applications. One major issue that could strongly impede the progress of such efforts is the lack of understanding of the mathematical properties of the SSIM measure. For example, some highly desirable properties such as convexity and triangular inequality that are possessed by the mean squared error may not hold. In this paper, we first construct a series of normalized and generalized (vector-valued) metrics based on the important ingredients of SSIM. We then show that such modified measures are valid distance metrics and have many useful properties, among which the most significant ones include quasi-convexity, a region of convexity around the minimizer, and distance preservation under orthogonal or unitary transformations. The groundwork laid here extends the potentials of SSIM in both theoretical development and practical applications.
We propose a contour morphing framework that allows large deformations and topological changes while guaranteeing non self-intersecting contours. Instead of explicitly matching contour points, the ...proposed algorithm combines an implicit contour representation with state-of-the-art deformable image registration. Synthetic and real-life examples from a meteorological application are presented to demonstrate the efficacy of the framework.
Abstract
The surface precipitation network in Canada suffers from large data gaps due to the challenge of covering a large country with a low population density. A proof-of-concept for an optimal ...network design is proposed to more efficiently estimate precipitation in Canada with the design goal of minimizing the interpolation uncertainty. The network design is based on a statistical model of precipitation that accounts for intermittency and non-Gaussianity of precipitation. Our results indicate that the greatest needs for new stations are in British Columbia, where coastal and mountain climate leads to more uncertainty in precipitation amounts, while the Prairie Provinces (Alberta, Saskatchewan, and Manitoba) could gain efficiencies by reducing their network size. Despite the current low density of stations in the territories north of Canada, these drier and colder regions only have a moderate need for more stations, mostly in the mountainous regions of Yukon. However, from a spatially varying wind undercatch measurement error model, it is shown that these northern regions have greatest need for higher-accuracy measurements.
Significance Statement
The proposed methodology can guide in the optimal placement of precipitation gauges across a large country such as Canada, which will provide value for money in how rain and snow are monitored.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Abstract
The clinical venous thromboembolism (VTE) pattern often shows wide heterogeneity within relatives of a VTE-affected family, although they carry the same thrombophilia defect. It is then ...mandatory to develop additional tools for assessing VTE risk in families with thrombophilia. This study aims to assess whether common environmental and genetic risk factors for VTE contribute to explain this heterogeneity. A total of 2,214 relatives from 651 families with known inherited thrombophilia were recruited at the referral center for thrombophilia in Marseilles, France, from 1986 to 2013. A thrombophilia screening was systematically performed in all included relatives. According to the severity of the thrombophilia defect, individuals were split into three groups: no familial defect, mild thrombophilia, and severe thrombophilia. In addition, common genetic factors (ABO blood group and 11 polymorphisms selected on the basis of their association with VTE in the general population) were genotyped. Furthermore, body mass index and smoking were collected. VTE incidence was 1.74, 3.64, and 6.40 per 1,000 person-years in individuals with no familial defect, mild thrombophilia, and severe thrombophilia, respectively. Five common risk factors were associated with VTE in this population: obesity, smoking, ABO blood group, and
F11
_rs2036914 and
FGG
_rs2066865 polymorphisms. These common factors were then included into a three-level risk score. The score was highly efficient for assessing VTE risk in mild thrombophilia patients by identifying two groups with different VTE risk; individuals with low score had the same risk as individuals with no familial defect whereas individuals with high score had the same risk as individuals with severe thrombophilia. An overall score including the five items plus the thrombophilia status was built and displayed an area under the receiver operating characteristic curve of 0.702 for discriminating VTE and non-VTE relatives. In conclusion, integrating common environmental and genetic risk factors improved VTE risk assessment in relatives from families with thrombophilia.
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