The MRI-Hallmarks of Liver Neroendocrine Metastases with Different Localization of Primary Neroendocrine Tumor

Purpose: To identify the MRI-hallmarks of liver metastatic neuroendocrine tumors (mNETs) with different localization of primary tumor.Material and methods: 75 liver mNET patients were enrolled in the study. The hepatic metastasis patients were divided into two groups: with pancreatic mNETs (n = 37) and with gastrointestinal tract (gut) mNETs (n = 38), including those of a stomach, small and large bowel, and appendicular primary. All patients underwent abdominal contrast-enhanced MRI with the measurement: the number and the maximum size of the lesions, the presence and size of avascular zones in the lesions, the presence of MRI signs of hemoglobin deg-radation products. In the region of interest, which corresponded to a rounded section in the solid portions of metastases, were measured quantitative indicators of signal intensity on T2-weighted images (WI), native and post-contrast T1-WI, the degree of accumulation of MR contrast agent (MRCA) and its washout, the value of apparent diffusion coefficient (ADC). A total of 171 lesions were assessed. The data were compared in the varying localization of the primary NET groups of patients.Results: The study demonstrated that the solid portion of the gut mNETs compared with that of the pancreatic mNETs are characterized by lower ADC-value (p = 0.0102, medians: pancreatic mNETs — 1036 × 10–3 mm2/s, gut mNETs — 846 × 10–3 mm2/s), less active accumulation of MRCA on the arterial (p = 0.0002, medians: pan-creatic mNETs — 1.48, gut mNETs — 1.24) and venous (p = 0.0026, median: pancreatic mNETs — 2.22, gut mNETs — 1.9) phases of contrast enhancement, longer washout of MRCA (p = 0.0057, median: pan-creas mNETs — 0.92, gut mNETs — 0.98). Based on regression-factor analysis, a model for determining the localization of primary tumors based on MRI signs of liver mNETs was created with an accuracy of 93.8 %.Conclusion: Gut mNETs compared with that of the pancreatic mNETs are characterized by lower ADC-value, less active accumulation and longer washout of MRCA. The data can be used to draw up a personalized examination plan of patient with liver mNETs from the unknown primary.

Amyloid and Amyloid-Like Aggregates: Diversity and the Term Crisis

Active accumulation of the data on new amyloids continuing nowadays dissolves boundaries of the term “amyloid”. Currently, it is most often used to designate aggregates with cross-β structure. At the same time, amyloids also exhibit a number of other unusual properties, such as: detergent and protease resistance, interaction with specific dyes, and ability to induce transition of some proteins from a soluble form to an aggregated one. The same features have been also demonstrated for the aggregates lacking cross-β structure, which are commonly called “amyloid-like” and combined into one group, although they are very diverse. We have collected and systematized information on the properties of more than two hundred known amyloids and amyloid-like proteins with emphasis on conflicting examples. In particular, a number of proteins in membraneless organelles form aggregates with cross-β structure that are morphologically indistinguishable from the other amyloids, but they can be dissolved in the presence of detergents, which is not typical for amyloids. Such paradoxes signify the need to clarify the existing definition of the term amyloid. On the other hand, the demonstrated structural diversity of the amyloid-like aggregates shows the necessity of their classification.

Mycosporine-Like Amino Acids (MAAs) in Zooplankton

Organisms have different adaptations to avoid damage from ultraviolet radiation and one such adaptation is the accumulation of mycosporine-like amino acids (MAAs). These compounds are common in aquatic taxa but a comprehensive review is lacking on their distribution and function in zooplankton. This paper shows that zooplankton MAA concentrations range from non-detectable to ~13 µg mgDW−1. Copepods, rotifers, and krill display a large range of concentrations, whereas cladocerans generally do not contain MAAs. The proposed mechanisms to gain MAAs are via ingestion of MAA-rich food or via symbiotic bacteria providing zooplankton with MAAs. Exposure to UV-radiation increases the concentrations in zooplankton both via increasing MAA concentrations in the phytoplankton food and due to active accumulation. Concentrations are generally low during winter and higher in summer and females seem to deposit MAAs in their eggs. The concentrations of MAAs in zooplankton tend to increase with altitude but only up to a certain altitude suggesting some limitation for the uptake. Shallow and UV-transparent systems tend to have copepods with higher concentrations of MAAs but this has only been shown in a few species. A high MAA concentration has also been shown to lead to lower UV-induced mortality and an overall increased fitness. While there is a lot of information on MAAs in zooplankton we still lack understanding of the potential costs and constraints for accumulation. There is also scarce information in some taxa such as rotifers as well as from systems in tropical, sub(polar) areas as well as in marine systems in general.

SMA Selectively Codes the Active Accumulation of Temporal, Not Spatial, Magnitude

Estimating duration depends on the sequential integration (accumulation) of temporal information in working memory. Using fMRI, we directly compared the accumulation of information in temporal versus spatial domains. Participants estimated either the duration or distance of the dynamic trajectory of a moving dot or, in a control condition, a static line stimulus. Comparing the duration versus distance of static lines activated an extensive cortico-striatal network. By contrast, comparing the duration versus distance of dynamic trajectories, both of which required sequential integration of information, activated SMA alone. Indeed, activity in SMA, as well as right inferior occipital cortex, increased parametrically as a function of stimulus duration and also correlated with individual differences in the propensity to overestimate stimulus duration. By contrast, activity in primary visual cortex increased parametrically as a function of stimulus distance. Crucially, a direct comparison of the parametric responses to duration versus distance revealed that activity in SMA increased incrementally as a function of stimulus duration but not as a function of stimulus distance. Collectively, our results indicate that SMA responds to the active accumulation of information selectively in the temporal domain.