Decreased mebrofenin uptake in patients with non-colorectal liver tumors requiring liver volume augmentation-a single-center analysis

BACKGROUND

Posthepatectomy liver failure (PHLF) remains a life-threatening complication after hepatectomy. To reduce PHLF, a preoperative assessment of liver function is indispensable. For this purpose, 99mTc-mebrofenin hepatobiliary scintigraphy with SPECT (MSPECT) can be used. The aim of the current study was to evaluate the predictive value of MSPECT for PHLF in patients with non-colorectal liver tumors (NCRLT) compared to patients with colorectal liver metastasis (CRLM) undergoing extended liver resection.

METHODS

We included all patients undergoing extended liver resections via two-stage procedures between January 2019 and December 2021 at the University Medical Center Hamburg-Eppendorf, Germany. All patients received a preoperative MSPECT.

RESULTS

Twenty patients were included. In every fourth patient, PHLF was observed. Four patients had PHLF grade C. There were no differences between patients with CRLM and NCRLT regarding PHLF rate and future liver remnant (FLR) volume. Patients with CRLM had higher mebrofenin uptake in the FLR compared to those with NCRLT (2.49%/min/m2 vs. 1.51%/min/m2; p = 0.004).

CONCLUSION

Mebrofenin uptake in patients with NCRLT was lower compared to those patients with CRLM. However, there was no difference in the PHLF rate and FLR volume. Cut-off values for the mebrofenin uptake might need adjustments for different surgical indications, surgical procedures, and underlying diseases.

Contribution of cultural heritage values to steppe conservation on ancient burial mounds of Eurasia

Civilizations, including ancient ones, have shaped global ecosystems in many ways through coevolution of landscapes and humans. However, the cultural legacies of ancient and lost civilizations are rarely considered in the conservation of the Eurasian steppe biome. We used a data set containing more than 1000 records on localities, land cover, protection status, and cultural values related to ancient steppic burial mounds (kurgans); we evaluated how these iconic and widespread landmarks can contribute to grassland conservation in the Eurasian steppes, which is one of the most endangered biomes on Earth. Using Bayesian logistic generalized regressions and proportional odds logistic regressions, we examined the potential of mounds to preserve grasslands in landscapes with different levels of land-use transformation. We also compared the conservation potential of mounds inside and outside protected areas and assessed whether local cultural values support the maintenance of grasslands on them. Kurgans were of great importance in preserving grasslands in transformed landscapes outside protected areas, where they sometimes acted as habitat islands that contributed to habitat conservation and improved habitat connectivity. In addition to steep slopes hindering ploughing, when mounds had cultural value for local communities, the probability of grassland occurrence on kurgans almost doubled. Because the estimated number of steppic mounds is about 600,000 and similar historical features exist on all continents, our results may be applicable at a global level. Our results also suggested that an integrative socioecological approach in conservation might support the positive synergistic effects of conservation, landscape, and cultural values.

First Survey of the Vascular and Cryptogam Flora on Bulgaria's Ancient Mounds

This work represents the first study of the floristic diversity on Bulgaria's ancient mounds. The objective of this research was to assess the importance of the mounds for the preservation of the native vascular and cryptogam flora. Our sampling design included 111 ancient mounds distributed throughout the country. We recorded a total of 1059 vascular plants, 58 bryophytes and 61 lichen taxa. Despite their small area, the mounds were shown to preserve nearly a quarter of the Bulgarian flora. The vegetation cover on the mounds included 61% perennials indicating a long-term persistence and stability. The majority (98%) of the established vascular plants were native species. Although the conservation significance of the vascular plant species were not common, we recorded 2 critically endangered, 9 endangered and 14 Balkan endemics during the present study. The lichen Arthopyrenia salicis was recorded for the first time in Bulgaria and a new locality of the rare bryophyte Ceratodon conicus was discovered. The established compositional difference between plots from the northern and southern slopes of the mounds (88.95%) is a testament to the high local habitat diversity. The prevalence of species characteristic for Festuco-Brometea suggests that the mounds preserve fragments of native grasslands and steppes. The variation in cover of agricultural and other human modified areas in the mounds' immediate surroundings did not substantially affect their species richness. We argue that the ancient mounds should be taken into consideration in future green space planning.

The importance of developing care-worker-centered robotic aides in long-term care

Recent research points to the fact that new medical technological innovations are just as relevant in the context of long-term care or chronic care as they are in the context of acute care. In the spirit of the Nuffield Foundation recommendations, this paper explores the possibilities of using robotic aides in long-term care and identifies the tensions that must be considered and addressed if robotics is to be introduced successfully in nursing homes. Our examination is two-pronged. First, we delve into a fundamental issue surrounding AI, namely that of consciousness. We argue that automation will always have only a limited use in caregiving since caregiving as an activity requires the use of human-type, that is, organic, consciousness. We support the thesis that the emergence and formation of human-type consciousness require feelings such as empathy and the sense of touch, which, in turn, create the sense of kinship with fellow human beings. And second, we examine the benefits as well as risks of using robotic aides such as ZORA and PARO in long-term care facilities. More specifically, we look at ZORA's use in a group setting, and PARO's use in an individual setting. We emphasize that long-term care is one-on-one care, including but not limited to intimate care. Crucially, we argue that touch is at the heart of this type of care. We argue that some of the tensions with the use of robotic aides are generated precisely because of the lack of human touch.

Linking environmental heterogeneity and plant diversity: The ecological role of small natural features in homogeneous landscapes

Small natural features (SNFs), such as road verges, midfield islets, rocky outcrops and ancient burial mounds, provide safe havens for species of natural habitats in human-modified landscapes; therefore, their great ecological importance is in contrast to their small size. SNFs often have a high topographical heterogeneity and abiotic conditions, which differ from their surroundings; therefore, they provide a unique opportunity for establishing links between environmental heterogeneity (EH) and biodiversity. However, no study has so far investigated the EH components of topographically heterogeneous SNFs in a comprehensive framework, by linking environmental and biotic parameters. To fill this knowledge gap, we evaluated the EH components and their effect on biodiversity on ancient mounds covered by semi-natural grasslands in the Pannonian (Hungary) and Continental (Bulgaria) biogeographical regions. We designated 16 study sites, each containing a few-metre-high mounds with five microsites (top, north-, east-, south- and west-facing slopes) and a nearby plain grassland. At each microsite, we measured soil moisture, soil chemical properties, solar radiation and microclimate; and recorded the cover of vascular plants in a total of 480 plots. On the mounds, topographical heterogeneity was associated with sharp differences in microclimate and soil properties. Besides the contrast between mild north-facing and harsh south-facing slopes, east- and west-facing slopes also sustained unique microsites characterised by dynamic diurnal changes in air temperature and vapour pressure deficit. Various combinations of the EH components resulted in unique plant species compositions within the microsites, and supported the co-occurrence of species typical of contrasting habitat types, even within a couple of metres. By combining high-resolution measurements of abiotic factors with fine-scale vegetation sampling, our study provides evidence that widespread SNFs with complex topography harbour several grassland-specialist plant species and introduce a high level of EH to otherwise homogeneous plain landscapes, which cover one third of the global land area.

Performance evaluation of a novel multi-pinhole collimator for dopamine transporter SPECT

There is a tradeoff between spatial resolution and count sensitivity in SPECT with conventional collimators. Multi-pinhole (MPH) collimator technology has potential for concurrent improvement of resolution and sensitivity in clinical SPECT of 'small' organs. This study evaluated a novel MPH collimator specifically designed for dopamine transporter (DAT) SPECT with a triple-head SPECT camera. Count sensitivity was measured with a ^99mTc point source placed on the lattice points of a 1 cm grid covering the whole field-of-view (FOV). Spatial resolution was assessed with a Derenzo type hot rod phantom. An anthropomorphic striatum phantom was scanned with total activity representative of a typical patient scan and different striatum-to-background activity concentration ratios. Recovery of striatum-to-background contrast was assessed by the contrast-recovery-coefficient. Measurements were repeated with double-head SPECT with fan-beam or low-energy-high-resolution-high-sensitivity (LEHRHS) collimators. A patient referred to DAT SPECT because of suspicion of Parkinson's disease was scanned with both LEHRHS and MPH collimators after a single tracer injection. The axial MPH sensitivity profile was approximately symmetrical around its peak, although it was shifted 7 cm towards the patient to simplify positioning. Peak sensitivity of the triple-head MPH system in the center of the FOV was 620 cps MBq^-1 compared to 225 cps MBq^-1 for the double-head fan-beam system. Sensitivity of the MPH system decreased towards the edges of the FOV. The full width of the sensitivity profile at 200 cps MBq^-1 was 21 cm transaxially and 11 cm axially. In MPH SPECT of the Derenzo phantom all rods with ≥ 5 mm diameter were clearly visible. MPH SPECT improved striatal contrast recovery by ≥ 20% compared to fan-beam SPECT. The patient scan demonstrated good image quality of MPH SPECT with almost PET-like delineation of putamen and caudate nucleus. SPECT with dedicated MPH collimators provides considerable improvement of the resolution-sensitivity tradeoff in DAT SPECT compared to SPECT with fan-beam or LEHRHS collimators.

Invader presence disrupts the stabilizing effect of species richness in plant community recovery after drought

Higher biodiversity can stabilize the productivity and functioning of grassland communities when subjected to extreme climatic events. The positive biodiversity-stability relationship emerges via increased resistance and/or recovery to these events. However, invader presence might disrupt this diversity-stability relationship by altering biotic interactions. Investigating such disruptions is important given that invasion by non-native species and extreme climatic events are expected to increase in the future due to anthropogenic pressure. Here we present one of the first multisite invader × biodiversity × drought manipulation experiment to examine combined effects of biodiversity and invasion on drought resistance and recovery at three semi-natural grassland sites across Europe. The stability of biomass production to an extreme drought manipulation (100% rainfall reduction; BE: 88 days, BG: 85 days, DE: 76 days) was quantified in field mesocosms with a richness gradient of 1, 3, and 6 species and three invasion treatments (no invader, Lupinus polyphyllus, Senecio inaequidens). Our results suggest that biodiversity stabilized community productivity by increasing the ability of native species to recover from extreme drought events. However, invader presence turned the positive and stabilizing effects of diversity on native species recovery into a neutral relationship. This effect was independent of the two invader's own capacity to recover from an extreme drought event. In summary, we found that invader presence may disrupt how native community interactions lead to stability of ecosystems in response to extreme climatic events. Consequently, the interaction of three global change drivers, climate extremes, diversity decline, and invasive species, may exacerbate their effects on ecosystem functioning.

Computer simulations suggest that acute correction of hyperglycaemia with an insulin bolus protocol might be useful in brain FDG PET

Aim: FDG PET in hyperglycaemic subjects often suffers from limited statistical image quality, which may hamper visual and quantitative evaluation. In our study the following insulin bolus protocol is proposed for acute correction of hyperglycaemia (> 7.0 mmol/l) in brain FDG PET. (i) Intravenous bolus injection of short-acting insulin, one I.E. for each 0.6 mmol/l blood glucose above 7.0. (ii) If 20 min after insulin administration plasma glucose is ≤ 7.0 mmol/l, proceed to (iii). If insulin has not taken sufficient effect step back to (i). Compute insulin dose with the updated blood glucose level. (iii) Wait further 20 min before injection of FDG. (iv) Continuous supervision of the patient during the whole scanning procedure. Methods: The potential of this protocol for improvement of image quality in brain FDG PET in hyperglycaemic subjects was evaluated by computer simulations within the Sokoloff model. A plausibility check of the prediction of the computer simulations on the magnitude of the effect that might be achieved by correction of hyperglycaemia was performed by retrospective evaluation of the relation between blood glucose level and brain FDG uptake in 89 subjects in whom FDG PET had been performed for diagnosis of Alzheimer's disease. Results: The computer simulations suggested that acute correction of hyperglycaemia according to the proposed bolus insulin protocol might increase the FDG uptake of the brain by up to 80%. The magnitude of this effect was confirmed by the patient data. Conclusion: The proposed management protocol for acute correction of hyper glycaemia with insulin has the potential to significantly improve the statistical quality of brain FDG PET images. This should be confirmed in a prospective study in patients.

Global scaling for semi-quantitative analysis in FP-CIT SPECT

Semi-quantitative characterization of dopamine transporter availability from single photon emission computed tomography (SPECT) with 123I-ioflupane (FP-CIT) is based on uptake ratios relative to a reference region. The aim of this study was to evaluate the whole brain as reference region for semiquantitative analysis of FP-CIT SPECT. The rationale was that this might reduce statistical noise associated with the estimation of non-displaceable FP-CIT uptake. Patients, methods: 150 FP-CIT SPECTs were categorized as neurodegenerative or non-neurode- generative by an expert. Semi-quantitative analysis of specific binding ratios (SBR) was performed with a custom-made tool based on the Statistical Parametric Mapping software package using predefined regions of interest (ROIs) in the anatomical space of the Montreal Neurological Institute. The following reference regions were compared: predefined ROIs for frontal and occipital lobe and whole brain (without striata, thalamus and brainstem). Tracer uptake in the reference region was characterized by the mean, median or 75th percentile of its voxel intensities. The area (AUC) under the receiver operating characteristic curve was used as performance measure. Results: The highest AUC of 0.973 was achieved by the SBR of the putamen with the 75th percentile in the whole brain as reference. The lowest AUC for the putamen SBR of 0.937 was obtained with the mean in the frontal lobe as reference. Conclusion: We recommend the 75th percentile in the whole brain as reference for semi-quantitative analysis in FP-CIT SPECT. This combination provided the best agreement of the semi-quantitative analysis with visual evaluation of the SPECT images by an expert and, therefore, is appropriate to support less experienced physicians.

FDG PET/CT in cancer therapy monitoring

Objectives: We developed and tested a software tool for computer-assisted analysis of FDG-PET/CT in cancer therapy monitoring. The tool provides automatic semi-quantitative analysis of a baseline scan together with up to two follow-up scans (standardized uptake values, glycolytic volume). The tool also supports visual analysis by local spatial registration which allows display of tumor lesions with the same orientation in all scans. The tool’s stability and accuracy was tested at typical everyday image quality. Patients, methods: Ten unselected cancer patients in whom three FDG PET/CT scans had been performed were included. A total of 18 lesions were analyzed. Results: Automatic lesion tracking worked properly in all lesions but one. In this lesion local coregistration had to be adjusted manually tuwhich, however, is easily performed with the tool. Semi-automatic lesion segmentation and fully automatic semi-quantitative analysis worked properly in all cases. Computer-assisted analysis was significantly less time consuming than manual analysis. Conclusions: The novel software tool appears useful for analysis of FDGPET/ CT in cancer therapy monitoring in clinical routine patient care.

Mollusc communities in Bulgarian fens: predictive power of the environment, vegetation, and spatial structure in an isolated habitat

Mollusc communities of previously unexplored Bulgarian fens were studied in order to determine and generalise the patterns of species richness and composition along the mineral richness gradient. The aim was also to compare predictive values of the environment, vegetation and spatial structure. Altogether, 44 mollusc species were recorded at 40 treeless fen sites. Species richness varied from 0 to 18 species per site, and it was positively associated with the mineral gradient and negatively with altitude. However, the best predictor was obtained using plant species composition. All explanatory variables had higher effect on land snails than on the entire mollusc assemblage (including aquatic species). Species richness and abundance were significantly and positively correlated with the species composition turnover; the communities were highly nested, with poor sites having subsets of the fauna found in the richest. The main direction of mollusc species turnover was highly associated with that observed for vegetation, and the main gradient of plant species composition was able to explain nearly 20% of total variation in mollusc data. We found that spatial structure explained by far the highest proportion of independent variation, which reflected the high level of geographical isolation of Bulgarian fens and regional differences independent of any environmental variation. Our results demonstrate (1) the general role of mineral richness gradient for structuring mollusc communities in fens, (2) the pivotal indicator role of plant species composition in predicting species composition of mollusc communities, despite being trophically independent and (3) the effect of isolation and origins of the habitat on species composition: most species have wide geographical distributions within the habitat type, and geographical patterns within Bulgaria may have a stochastic element.

Temperature dependence of resonance Raman spectra of carotenoids

To understand the mechanism of the photoprotective and antioxidative functions of carotenoids, it is essential to have a profound knowledge of their excited electronic and vibronic states. In the present study we investigate the most powerful antioxidants: β-carotene and lutein by means of resonance Raman spectroscopy. The aim was to study in detail their Raman spectra in solution at room temperature and their changes as a function of temperature. To measure the spectra in their natural environment pyridine has been used as a solvent. It has been chosen because of its polarizability (n=1.5092) which is close to that of membrane lipids and proteins. The temperature dependence of the most intensive ν(1) band in the range from 77 K to 295 K at 514.5 nm excitation has been obtained. It was found that in pyridine the CC stretching frequency, its intensity, line shape, and line width are very sensitive to the temperature (the sensitivity being different for the two studied carotenoids). The observed linear temperature dependence of the CC stretching frequency is explained by a mechanism involving changes of the vibronic coupling and the extent of π-electron delocalization. The different behavior of the temperature-induced broadening of the ν(1) band and its intensity for the two studied carotenoids can be associated with the different nature of their solid matrices: glassy for β-carotene and crystalline-like for lutein, owing to their different chemical structures.

IBZM SPECT and FDG PET in the differential diagnosis of Parkinsonian syndromes: comparison with respect to inter-rater agreement

AIM

Both IBZM SPECT and FDG PET may be used for differentiation between Parkinson's disease (PD) and atypical neurodegenerative parkinsonian syndromes (APS). However, there are only very limited data of both modalities in the same subjects. The present study compared both modalities with respect to inter-rater agreement in 30 patients with neurodegenerative parkinsonian syndromes (PS) confirmed by FP-CIT SPECT.

METHODS

IBZM SPECT and FDG PET were categorized as PD or APS by visual inspection of standardized report pages and statistical parametric maps (SPMs). Categorization was performed independently by five readers. Inter-rater agreement was quantified using Cohen's kappa kappa.

RESULTS

IBZM SPECT resulted in PD and APS in 11 and 19 cases, respectively (majoritarian categorization). Inter-rater agreement was kappa=0.64+/-0.10. FDG PET resulted in PD and APS in 12 and 18 cases, respectively (majoritarian categorization). Inter-rater agreement was kappa=0.68+/-0.07. Majoritarian diagnosis disagreed between IBZM SPECT and FDG PET in 13 cases (43%). Semi-quantitative analysis of IBZM SPECT using the striatum-to-reference distribution volume ratio was in good agreement with visual categorization (area under ROC curve 0.92).

CONCLUSION

In neurodegenerative PS, inter-rater agreement of visual analysis is substantial in both IBZM SPECT and FDG PET. Furthermore, (I) visual analysis of IBZM SPECT is reliable if adequate standardized image display is used, (II) visual analysis of FDG SPMs allows unique categorization as either PD or APS in most subjects, and (III) IBZM SPECT and FDG PET are discordant in a significant fraction of cases.

Theoretical study of the phonon spectra of multiferroic BiFeO(3) nanoparticles

The phonon properties of multiferroic BiFeO(3) (BFO) nanoparticles are studied using a Green's function technique on the basis of the Heisenberg and the transverse Ising models, taking into account anharmonic spin-phonon and phonon-phonon interaction terms. The phonon spectrum is obtained for different exchange, magnetoelectric, and spin-phonon interaction constants. The influence of temperature, surface and size effects on the phonon energy and damping is discussed. The phonon energy and damping in BFO nanoparticles are greater in comparison to those in bulk BFO. The strong spin-phonon interactions lead to anomalies in the phonon spectrum around the magnetic and ferroelectric phase transitions. The influence of an applied magnetic field is studied, too. The predictions are consistent with experimental results.

Computer simulations suggest that acute correction of hyperglycaemia with an insulin bolus protocol might be useful in brain FDG PET

AIM

FDG PET in hyperglycaemic subjects often suffers from limited statistical image quality, which may hamper visual and quantitative evaluation. In our study the following insulin bolus protocol is proposed for acute correction of hyperglycaemia (>7.0 mmol/l) in brain FDG PET. (i) Intravenous bolus injection of short-acting insulin, one I.E. for each 0.6 mmol/l blood glucose above 7.0. (ii) If 20 min after insulin administration plasma glucose is <or=7.0 mmol/l, proceed to (iii). If insulin has not taken sufficient effect step back to (i). Compute insulin dose with the updated blood glucose level. (iii) Wait further 20 min before injection of FDG. (iv) Continuous supervision of the patient during the whole scanning procedure.

METHODS

The potential of this protocol for improvement of image quality in brain FDG PET in hyperglycaemic subjects was evaluated by computer simulations within the Sokoloff model. A plausibility check of the prediction of the computer simulations on the magnitude of the effect that might be achieved by correction of hyperglycaemia was performed by retrospective evaluation of the relation between blood glucose level and brain FDG uptake in 89 subjects in whom FDG PET had been performed for diagnosis of Alzheimer's disease.

RESULTS

The computer simulations suggested that acute correction of hyperglycaemia according to the proposed bolus insulin protocol might increase the FDG uptake of the brain by up to 80%. The magnitude of this effect was confirmed by the patient data.

CONCLUSION

The proposed management protocol for acute correction of hyper glycaemia with insulin has the potential to significantly improve the statistical quality of brain FDG PET images. This should be confirmed in a prospective study in patients.

Size, anisotropy and doping effects on the coercive field of ferromagnetic nanoparticles

The influence of size, anisotropy and doping effects on the hysteresis loop of ferromagnetic nanoparticles is studied, based on the modified Heisenberg model. A Green's function technique in real space allows the calculation of the dependence of the magnetization on the temperature, magnetic field, anisotropy, defects and particle size. It is demonstrated that the coercive field H(c) is very sensitive to the surface single-ion anisotropy, and to the exchange interaction constant on the surface J(s) and in the defect shells J(d). With respect to the strong surface single-site anisotropy D(s), we observe at small particle size, N = 4 shells, a maximum in the size dependence of the coercive field, whereas for the small surface anisotropy there is no maximum. Taking into account that J can be different in the defect shells compared to the case without defects, we have obtained for the first time that the coercive field H(c), the permanent magnetization M(r) and the Curie temperature T(C) can increase or decrease for different kinds of doping ions. The dependence on the particle size is discussed, too. The results are in accordance with the experimental data.