Phospholipids are synthesized primarily within the endoplasmic reticulum and are subsequently distributed to various subcellular membranes to maintain the unique lipid composition of specific ...organelles. As a result, in most cases, the steady-state localization of membrane phospholipids does not match their site of synthesis. This raises the question of how diverse lipid species reach their final membrane destinations and what molecular processes provide the energy to maintain the lipid gradients that exist between various membrane compartments. Recent studies have highlighted the role of inositol phospholipids in the nonvesicular transport of lipids at membrane contact sites. This review attempts to summarize our current understanding of these complex lipid dynamics and highlights their implications for defining future research directions.
To intraindividually compare hepatocellular carcinoma (HCC) washout between MRIs using hepatobiliary agent (HBA) and extracellular agent (ECA).
This study included 114 prospectively enrolled patients ...with chronic liver disease (mean age, 55 ± 9 years; 94 men) who underwent both HBA-MRI and ECA-MRI before surgical resection for HCC between November 2016 and May 2019. For 114 HCCs, the lesion-to-liver visual signal intensity ratio (SIR) using a 5-point scale (-2 to +2) was evaluated in each phase. Washout was defined as negative visual SIR with temporal reduction of visual SIR from the arterial phase. Illusional washout (IW) was defined as a visual SIR of 0 with an enhancing capsule. The frequency of washout and MRI sensitivity for HCC using LR-5 or its modifications were compared between HBA-MRI and ECA-MRI. Subgroup analysis was performed according to lesion size (< 20 mm or ≥ 20 mm).
The frequency of portal venous phase (PP) washout with HBA-MRI was comparable to that of delayed phase (DP) washout with ECA-MRI (77.2% 88/114 vs. 68.4% 78/114;
= 0.134). The frequencies were also comparable when IW was allowed (79.8% 91/114 for HBA-MRI vs. 81.6% 93/114 for ECA-MRI;
= 0.845). The sensitivities for HCC of LR-5 (using PP or DP washout) were comparable between HBA-MRI and ECA-MRI (78.1% 89/114 vs. 73.7% 84/114;
= 0.458). In HCCs < 20 mm, the sensitivity of LR-5 was higher on HBA-MRI than on ECA-MRI (70.8% 34/48 vs. 50.0% 24/48;
= 0.034). The sensitivity was similar to each other if IW was added to LR-5 (72.9% 35/48 for HBA-MRI vs. 70.8% 34/48 for ECA-MRI;
> 0.999).
Extracellular phase washout for HCC diagnosis was comparable between MRIs with both contrast agents, except for tumors < 20 mm. Adding IW could improve the sensitivity for HCC on ECA-MRI in tumors < 20 mm.
This study aimed to compare two methods of crosslinking collagen type I on implanted titanium surfaces, that is, using glutaraldehyde (GA) or gamma-rays (GRs), in a beagle dog model. For in vivo ...experiments, implants were allocated to three groups and applied to mandibular bone defects in beagle dogs; Group SLA; non-treated Sandblasted, large grit, acid-etched (SLA) implants, Group GA; SLA implants coated with GA crosslinked collagen type I, Group GR; SLA surface implants coated with collagen type I and crosslinked using 25 kGy of 60Co gamma radiation. New bone μCT volumes were obtained, and histologic and histometric analyses were performed in regions of interest. The GR group had significantly better new bone areas (NBAs) and bone to implant contact (BIC) results than the SLA group (p < 0.05), but the GA and GR groups were similar in this respect. New bone volumes and inter-thread bone densities (ITBD) were non-significantly different in the three groups (p > 0.05). Within the limits of this study, gamma-ray collagen crosslinking on titanium implants can be considered a substitute for glutaraldehyde crosslinking.
This clinical study aimed to predict the learning curve of wireless and wired intraoral scanners (IOSs) and to compare the reduction patterns of working time. Overall, 14 participants were enrolled ...in the study. The intraoral scanning procedure was repeated four times, each using wireless and wired IOSs (i700; MEDIT). The work time from the first to the 600th iterations was predicted using the Wright model. Regarding statistical analysis, the Mann-Whitney U-test was performed for comparison between wireless and wired IOSs and between groups with and without an IOS usage experience, and the Friedman test was performed to evaluate the time reduction (α = 0.05). There was a significant difference between wireless and wired IOSs in the first (P = 0.008) and the third (P = 0.035) iterations. Moreover, the time for 600 iterations was statistically significantly different between wireless and wired IOSs (P < 0.05); however, there was no significant difference after the sixth iteration (e.g., seventh iteration: P = 0.062). In wireless IOS, no significant difference was found between participants with and without an IOS usage experience after the 34th iteration (P = 0.053). The difference in the learning effect between wireless and wired IOSs can be overcome by initial learning; however, an IOS usage experience can affect the learning time of wireless IOSs.
The purpose of this study was to investigate whether ancillary features can help stratify malignancy risk in Liver Imaging Reporting and Data System (LI-RADS) category 3 (LR-3) and 4 (LR-4) ...observations.
This retrospective longitudinal study included 106 LR-3 or LR-4 observations on gadolinium-enhanced MRI obtained from January 2014 to December 2015 in 80 patients who were treatment naïve and at risk (mean age, 58.0 ± 10.7 SD years; 60 men). The presence of major and ancillary features, the category determined using only major features, and the final category adjusted by the application of ancillary features were retrospectively analyzed. MRI features were compared using generalized estimating equations, and cumulative incidence curves for malignancy were compared using log-rank tests with a resampling extension.
At 6-month follow-up, the cumulative incidence of observations initially categorized as LR-4, observations upgraded to LR-4, observations initially categorized as LR-3, and observations downgraded to LR-3 were 62.5%, 29.7%, 6.2%, and 0%, respectively. The cumulative incidence of malignancy did not differ between observations categorized by major feature as LR-3 and LR-4 (
= 0.12), but was higher in final observations categorized as LR-4 than in those categorized as LR-3 (
< 0.001). Among observations categorized by major feature as LR-3, the cumulative incidence of malignancy was higher in observations upgraded to LR-4 than in observations that were initially graded as LR-3 (
= 0.03), which showed differences in the frequency of restricted diffusion and mild-to-moderate T2-weighted hyperintensity (
< 0.001 for both).
Final categories determined with ancillary features, instead of categories determined by major features only, can help indicate malignancy risk in LR-3 and LR-4 observations on MRI.
Structural lipids are mostly synthesized in the endoplasmic reticulum (ER), from which they are actively transported to the membranes of other organelles. Lipids can leave the ER through vesicular ...trafficking or non-vesicular lipid transfer and, curiously, both processes can be regulated either by the transported lipid cargos themselves or by different secondary lipid species. For most structural lipids, transport out of the ER membrane is a key regulatory component controlling their synthesis. Distribution of the lipids between the two leaflets of the ER bilayer or between the ER and other membranes is also critical for maintaining the unique membrane properties of each cellular organelle. How cells integrate these processes within the ER depends on fine spatial segregation of the molecular components and intricate metabolic channeling, both of which we are only beginning to understand. This review will summarize some of these complex processes and attempt to identify the organizing principles that start to emerge. This article is part of a Special Issue entitled Endoplasmic reticulum platforms for lipid dynamics edited by Shamshad Cockcroft and Christopher Stefan.
•Lipid synthesizing enzymes are under product inhibition.•Lipid transport from the ER helps maintain lipid synthesis.•Inositol lipids control lipid transport between membranes.
•Sclerosing hemangioma (SH) can be distinguished from hepatic malignancies using MRI.•Margins, enhancement pattern, and no diffusion restriction were key features for SH.•Using these features, ...patients with suspected SH should undergo biopsy first.
To investigate the imaging features of gadoxetic acid-enhanced magnetic resonance imaging (MRI) to differentiate hepatic sclerosing hemangioma from malignant tumors.
This retrospective case-control study included 18 patients with sclerosing hemangioma and 54 patients with common hepatic malignant tumor, including hepatocellular carcinoma, metastatic adenocarcinoma, and cholangiocarcinoma, who were examined using gadoxetic acid-enhanced liver MRI from January 2008 to June 2019. Imaging features including signal intensity, tumor margins, enhancement pattern, and presence or absence of diffusion restriction were analyzed. Significant MRI features for predicting sclerosing hemangioma were identified using multivariable logistic regression analysis. Diagnostic performances of each imaging feature and combinations of significant imaging features were summarized.
In the multivariable analysis, irregular margins (odds ratio OR, 10.12; 95 % confidence interval CI, 1.27−80.94; p = 0.029), centripetal or internal nodular enhancement in the transitional phase (OR, 13.58; 95 % CI, 1.48−124.82; p = 0.021), and absence of diffusion restriction (OR, 39.20; 95 % CI, 4.82−318.49; p = 0.001) were significant imaging features for the diagnosis of sclerosing hemangioma. Presence of at least two significant imaging features had a sensitivity, specificity, and accuracy of 88.9 %, 96.3 %, and 94.4 %, respectively, for diagnosing sclerosing hemangioma.
Combinations of two or more of the significant imaging features (irregular margins, centripetal or internal nodular enhancement in the transitional phase, and absence of diffusion restriction) were effective for differentiating hepatic sclerosing hemangioma from malignant tumors using gadoxetic acid-enhanced MRI.
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