Oh I remember the beauty and aesthetics of guilin!: Exploring the implications of memorability on tourist loyalty through a two-wave panel data.

The travel and tourism industry is among most severely impacted by natural disasters, terrorism, financial crises, and pandemics. Scholars are currently paying attention to how to revive tourism and establish tourist loyalty in the post-pandemic era. Aesthetics is a fundamental component of the tourist experience, and significantly affects tourist loyalty, intention, and behavior. However, research on destination aesthetics is limited, with most studies neglecting the role of memorability in the outcomes of aesthetics, particularly after the pandemic. Therefore, this study explores the mediating role of memorability in the effects of the aesthetic experiential qualities (scenery, cleanliness, harmony, art/architecture, and genuineness) of a nature-based tourism destination on tourist loyalty. Based on a two-wave panel data approach, 509 survey responses were collected and analyzed using Smarts. The findings indicate that the aesthetic experiential qualities positively affect tourists' memorability. Although three of the five aesthetic qualities (scenery, harmony, art/architecture) demonstrated no direct impact on loyalty, all the qualities had significant indirect effects on loyalty through the mediation of memorability. This study provides insights and new perspectives for promoting tourist loyalty in the context of post-pandemic tourism recovery.

Liver kidney microsome antibodies. Analysis of a laboratory series.

Objectives: The objectives were to characterize the liver kidney microsome (LKM) antibody profile of a 14-month-old girl with autoimmune hepatitis and analyze the laboratory prevalence of LKM positivity. Design and methods: This is retrospective analysis of the LKM antibody immunofluorescence tests performed by the Immunology Laboratory of Johns Hopkins Hospital from September 8, 2020 to July 31, 2022. LKM positive sera were also tested by an ELISA for LKM1 antibodies, which recognize the cytochrome P450 2D6 antigen. In silico analysis of 2D6 mRNA expression across anatomical sites was performed using Bgee and GTEx Portal databases. Results: Of the total of 1598 patients (893 F, 705 M, ages 0.8-94 years) tested for LKM antibodies, 3 were positive, yielding a 0.2% period prevalence. The clinical diagnosis was autoimmune hepatitis in the index case, acute viral hepatitis in a 3-yo male, and hepatocellular carcinoma in a 54-yo male. LKM antibodies yielded the classical homogenous staining pattern in the liver cytosol and proximal kidney tubular cells. The first two patients were also positive for LKM1 antibodies, whereas the third was negative. 2D6 mRNA was expressed highly in the liver, moderately in the duodenum, and minimally in other tissues. Conclusions: Overall, LKM antibodies are rare. They contribute to establish a diagnosis of autoimmune hepatitis, although they are also found in other liver diseases. The cytochrome P450 2D6 is one of the antigens recognized by LKM antibodies, but other antigens are likely targeted considering that 2D6 is minimally expressed in the kidney and yet LKM antibodies bind to kidney tubuli.

Quantitative analysis of mitochondrial membrane potential heterogeneity in unsynchronized and synchronized cancer cells.

Mitochondrial membrane potential (ΔΨm) is a global indicator of mitochondrial function. Previous reports on heterogeneity of ΔΨm were qualitative or semiquantitative. Here, we quantified intercellular differences in ΔΨm in unsynchronized human cancer cells, cells synchronized in G1, S, and G2, and human fibroblasts. We assessed ΔΨm using a two-pronged microscopy approach to measure relative fluorescence of tetramethylrhodamine methyl ester (TMRM) and absolute values of ΔΨm. We showed that ΔΨm is more heterogeneous in cancer cells compared to fibroblasts, and it is maintained throughout the cell cycle. The effect of chemical inhibition of the respiratory chain and ATP synthesis differed between basal, low and high ΔΨm cells. Overall, our results showed that intercellular heterogeneity of ΔΨm is mainly modulated by intramitochondrial factors, it is independent of the ΔΨm indicator and it is not correlated with intercellular heterogeneity of plasma membrane potential or the phases of the cell cycle.

Achieving Osmotic Stability in the Context of Critical Illness and Acute Kidney Injury During Continuous Renal Replacement Therapy.

The concept of osmotic stability during renal replacement therapy has received limited attention thus far. We report an illustrative case of a previously healthy 22 year old male presenting after prolonged ventricular fibrillation with 75 minutes of resuscitative efforts before regaining spontaneous perfusing rhythm. Central nervous system protecting hypothermia protocol and veno-arterious (VA) extracorporeal membrane oxygenator (ECMO) therapy were initiated at hospital admission due to refractory hypoxemia. Cardiovascular imaging procedures described global hypokinesis. Due to the combination of anuria, mixed acidosis and hemodynamic instability, we started continuous renal replacement therapy (CRRT) in continuous veno-venous hemodiafiltration functionality with added hypertonic saline solution (HTS) protocol, calculated to stabilize his serum sodium between 148 and 150 mEq/L. Serum osmolality also ranged between 321 and 317 mOsm/kg thereafter. Course was complicated by an acute right leg ischemia distal to VA ECMO cannula placement, requiring salvage therapy with cryoamputation. Vasoactive medication requirement and hemodynamics improved after the addition of intravenous (IV) hydrocortisone. Brain magnetic resonance imaging (MRI) 22 days post-arrest showed signals of limited hypoxic injury. He left the hospital in stable condition with limited neurologic sequelae. Therefore, the use of HTS during CRRT is a viable way to address potential or manifest cerebral edema and reduce the degree of cerebral injury.

Statin-dependent modulation of mitochondrial metabolism in cancer cells is independent of cholesterol content.

Statins, widely used to treat hypercholesterolemia, inhibit the 3-hydroxy-3-methylglutaryl-coenzyme A reductase, the rate-limiting enzyme of de novo cholesterol (Chol) synthesis. Statins have been also reported to slow tumor progression. In cancer cells, ATP is generated both by glycolysis and oxidative phosphorylation. Mitochondrial membrane potential (ΔΨ), a readout of mitochondrial metabolism, is sustained by the oxidation of respiratory substrates in the Krebs cycle to generate NADH and flavin adenine dinucleotide, which are further oxidized by the respiratory chain. Here, we studied the short-term effects of statins (3-24 h) on mitochondrial metabolism on cancer cells. Lovastatin (LOV) and simvastatin (SIM) increased ΔΨ in HepG2 and Huh7 human hepatocarcinoma cells and HCC4006 human lung adenocarcinoma cells. Mitochondrial hyperpolarization after LOV and SIM was dose and time dependent. Maximal increase in ΔΨ occurred at 10 µM and 24 h for both statins. The structurally unrelated atorvastatin also hyperpolarized mitochondria in HepG2 cells. Cellular and mitochondrial Chol remained unchanged after SIM. Both LOV and SIM decreased basal respiration, ATP-linked respiration, and ATP production. LOV and SIM did not change the rate of lactic acid production. In summary, statins modulate mitochondrial metabolism in cancer cells independently of the Chol content in cellular membranes without affecting glycolysis.-Christie, C. F., Fang, D., Hunt, E. G., Morris, M. E., Rovini, A., Heslop, K. A., Beeson, G. C., Beeson, C. C., Maldonado, E. N. Statin-dependent modulation of mitochondrial metabolism in cancer cells is independent of cholesterol content.

Fluconazole induces ROS in Cryptococcus neoformans and contributes to DNA damage in vitro.

Pathogenic basidiomycetous yeast, Cryptococcus neoformans, causes fatal meningitis in immunocompromised individuals. Fluconazole (FLC) is a fungistatic drug commonly administered to treat cryptococcosis. Unfortunately, FLC-resistant strains characterized by various degree of chromosomal instability were isolated from clinical patients. Importantly, the underlying mechanisms that lead to chromosomal instability in FLC-treated C. neoformans remain elusive. Previous studies in fungal and mammalian cells link chromosomal instability to the reactive oxygen species (ROS). This study provides the evidence that exposure of C. neoformans to FLC induces accumulation of intracellular ROS, which correlates with plasma membrane damage. FLC caused transcription changes of oxidative stress related genes encoding superoxide dismutase (SOD1), catalase (CAT3), and thioredoxin reductase (TRR1). Strikingly, FLC contributed to an increase of the DNA damage in vitro, when complexed with iron or copper in the presence of hydrogen peroxide. Strains with isogenic deletion of copper response protein metallothionein were more susceptible to FLC. Addition of ascorbic acid (AA), an anti-oxidant at 10 mM, reduced the inhibitory effects of FLC. Consistent with potential effects of FLC on DNA integrity and chromosomal segregation, FLC treatment led to elevated transcription of RAD54 and repression of cohesin-encoding gene SCC1. We propose that FLC forms complexes with metals and contributes to elevated ROS, which may lead to chromosomal instability in C. neoformans.

VDAC Regulation: A Mitochondrial Target to Stop Cell Proliferation.

Cancer metabolism is emerging as a chemotherapeutic target. Enhanced glycolysis and suppression of mitochondrial metabolism characterize the Warburg phenotype in cancer cells. The flux of respiratory substrates, ADP, and Pi into mitochondria and the release of mitochondrial ATP to the cytosol occur through voltage-dependent anion channels (VDACs) located in the mitochondrial outer membrane. Catabolism of respiratory substrates in the Krebs cycle generates NADH and FADH2 that enter the electron transport chain (ETC) to generate a proton motive force that maintains mitochondrial membrane potential (ΔΨ) and is utilized to generate ATP. The ETC is also the major cellular source of mitochondrial reactive oxygen species (ROS). αß-Tubulin heterodimers decrease VDAC conductance in lipid bilayers. High constitutive levels of cytosolic free tubulin in intact cancer cells close VDAC decreasing mitochondrial ΔΨ and mitochondrial metabolism. The VDAC-tubulin interaction regulates VDAC opening and globally controls mitochondrial metabolism, ROS formation, and the intracellular flow of energy. Erastin, a VDAC-binding molecule lethal to some cancer cell types, and erastin-like compounds identified in a high-throughput screening antagonize the inhibitory effect of tubulin on VDAC. Reversal of tubulin inhibition of VDAC increases VDAC conductance and the flux of metabolites into and out of mitochondria. VDAC opening promotes a higher mitochondrial ΔΨ and a global increase in mitochondrial metabolism leading to high cytosolic ATP/ADP ratios that inhibit glycolysis. VDAC opening also increases ROS production causing oxidative stress that, in turn, leads to mitochondrial dysfunction, bioenergetic failure, and cell death. In summary, antagonism of the VDAC-tubulin interaction promotes cell death by a "double-hit model" characterized by reversion of the proproliferative Warburg phenotype (anti-Warburg) and promotion of oxidative stress.

Opening of voltage dependent anion channels promotes reactive oxygen species generation, mitochondrial dysfunction and cell death in cancer cells.

Enhancement of aerobic glycolysis and suppression of mitochondrial metabolism characterize the pro-proliferative Warburg phenotype of cancer cells. High free tubulin in cancer cells closes voltage dependent anion channels (VDAC) to decrease mitochondrial membrane potential (ΔΨ), an effect antagonized by erastin, the canonical promotor of ferroptosis. Previously, we identified six compounds (X1-X6) that also block tubulin-dependent mitochondrial depolarization. Here, we hypothesized that VDAC opening after erastin and X1-X6 increases mitochondrial metabolism and reactive oxygen species (ROS) formation, leading to ROS-dependent mitochondrial dysfunction, bioenergetic failure and cell death. Accordingly, we characterized erastin and the two most potent structurally unrelated lead compounds, X1 and X4, on ROS formation, mitochondrial function and cell viability. Erastin, X1 and X4 increased ΔΨ followed closely by an increase in mitochondrial ROS generation within 30-60 min. Subsequently, mitochondria began to depolarize after an hour or longer indicative of mitochondrial dysfunction. N-acetylcysteine (NAC, glutathione precursor and ROS scavenger) and MitoQ (mitochondrially targeted antioxidant) blocked increased ROS formation after X1 and prevented mitochondrial dysfunction. Erastin, X1 and X4 selectively promoted cell killing in HepG2 and Huh7 human hepatocarcinoma cells compared to primary rat hepatocytes. X1 and X4-dependent cell death was blocked by NAC. These results suggest that ferroptosis induced by erastin and our erastin-like lead compounds was caused by VDAC opening, leading to increased ΔΨ, mitochondrial ROS generation and oxidative stress-induced cell death.

Fluconazole-Induced Ploidy Change in Cryptococcus neoformans Results from the Uncoupling of Cell Growth and Nuclear Division.

Cryptococcus neoformans is a pathogenic yeast that causes lethal cryptococcal meningitis in immunocompromised patients. One of the challenges in treating cryptococcosis is the development of resistance to azole antifungals. Previous studies linked azole resistance to elevated numbers of copies of critical resistance genes in aneuploid cells. However, how aneuploidy is formed in the presence of azole drugs remains unclear. This study showed that treatment with inhibitory concentrations of an azole drug, fluconazole (FLC), resulted in a significant population of cells with increased DNA content, through the following defects: inhibition of budding, premature mitosis, and inhibition of cytokinesis followed by replication in the mother cell. Inhibition of and/or a delay in cytokinesis led to the formation of cells with two or more daughter cells attached (multimeric cells). To investigate which part of cytokinesis fails in the presence of FLC, the dynamics of the actomyosin ring (AMR), septins, and Cts1, a protein involved in cell separation, were analyzed with time-lapse microscopy. Following the constriction of the AMR, septins assembled and the septum was formed between the mother and daughter cells. However, final degradation of the septum was affected. Enlarged cells with aberrant morphology, including multimeric cells, exhibited an increased potential to proliferate in the presence of FLC. These findings suggest that pleiotropic effects of FLC on growth and mitotic division lead to an increase in DNA content, resulting in cells less sensitive to the drug. Cells with increased DNA content continue to proliferate and therefore increase the chance of forming resistant populations. IMPORTANCE Azoles are antifungals that are widely utilized due to relatively low toxicity and cost of treatment. One of their drawbacks, however, is that azoles are primarily cytostatic, leaving fungal cells capable of developing drug resistance. The human pathogen Cryptococcus neoformans acquires resistance to the azole drug fluconazole (FLC) through the development of aneuploidy, leading to elevated expression of key resistance genes, a mechanism that is also common for Candida albicans (K. J. Kwon-Chung and Y. C. Chang, PLoS Pathog 8:e1003022, 2012, https://doi.org/10.1371/journal.ppat.1003022; J. Morschhäuser, J Microbiol 54:192-201, 2016, https://doi.org/10.1007/s12275-016-5628-4). However, the exact ways in which FLC contributes to increased resistance in either of these important fungal pathogens remain unclear. Here we found that FLC treatment leads to an increase in DNA content in C. neoformans through multiple mechanisms, potentially increasing the size of a pool of cells from which aneuploids with increased resistance are selected. This study demonstrated the importance of FLC's inhibitory effects on growth and cytokinesis in the generation of cell populations with decreased sensitivity to the drug.