Resurgence of goal-directed actions and habits.

This study investigated how goal-directed and habitual behaviors recover after extinction within the context of the resurgence effect, a form of relapse induced by the removal or worsening of alternative reinforcement. Rats were trained to press a target lever with one reinforcer (O1) for either minimal (4) or extended (16) sessions. An extinction test after the completion of O1 devaluation confirmed that minimal and extended training formed goal-directed and habitual behaviors, respectively. Then, pressing an alternative lever was reinforced with a second reinforcer (O2) while the target response was placed on extinction. When O2 was discontinued, the minimally trained target response resurged with goal-directed status as in the extinction test. However, the extinguished habitual behavior in the extensively trained rats did not recover as a habit but instead with goal-directed status, possibly due to the context specificity of habits or the introduction of a new response-reinforcer contingency. The critical finding that reinforcer devaluation consistently led to less resurgence regardless of the amount of acquisition training provides a clinical implication that coupling differential-reinforcement-of-alternative-behavior (DRA) treatments with the devaluation of the associated reinforcer of problematic behavior could effectively diminish its recurrence.

Transition between habits and goal-directed actions in the renewal effect.

Three experiments with rats explored whether previously extinguished goal-directed and habitual responding recover with the same status using an ABA renewal preparation. In Experiments 1a and 1b, a lever-press response was minimally (four sessions) or extensively (16 sessions) trained in one context (Context A) and extinguished in another context (Context B). Then, outcome devaluation took place in either Context A or Context B in which a food pellet reinforcing the response was paired with lithium chloride (LiCl) for devalued groups and with saline for a control group. Finally, renewal of the extinguished response was tested in both Contexts A and B. We confirmed that both minimally and extensively trained responses renewed as goal-directed action regardless of the context in which devaluation took place. This finding was replicated in Experiment 2 even after more extended acquisition training (32 sessions). However, another group that received outcome devaluation before but not after extinction training showed habitual performance during extinction training as well as in a subsequent renewal test. Experiment 3 replicated these results and confirmed that renewal of goal direction for rats that received extinction training immediately prior to outcome devaluation was not an artifact of consecutive LiCl exposures over a short period of time in Experiments 1 and 2, using a more reliable devaluation protocol. Overall, the present results extend previous findings suggesting that actions and habits renew with the same status by returning to the original context after extinction. The most critical finding is the differential effects of pre- and postextinction devaluation on the expression of habitual behavior; extinction prior to devaluation may convert a habitual performance into a goal-directed action. This novel finding is discussed in relation to recent studies that identified several factors contributing to a transition from habitual to goal-directed control of instrumental behavior. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Safety and efficacy of a defecation care algorithm based on ultrasonographic bowel observation in Japanese home-care settings: a single-case, multiple-baseline study.

AIM: To verify the efficacy of defecation care based on handheld ultrasonographic observations for functional constipation by visiting nurses skilled in bowel ultrasonography. METHODS: Home-care patients with suspected functional constipation receiving nursing visits were recruited in this multiple-baseline, single-case experiment with intervention points shifted by 1 week. A total of 15 older adults were categorized into 3-, 4-, 5- or 6-week intervention phases. Ultrasonographic observations of fecal retention in the colorectum and defecation care based on observations during the ordinal physical assessment were reviewed. Tau-U was used for confirming the efficacy of the intervention by measuring the number of non-artificial and artificial defecations, as well as hard stools per week, and the amount of non-stimulant and stimulant laxatives, enemas and suppositories per week. For evaluating safety, adverse events, such as bowel obstruction and incontinence-associated dermatitis, were confirmed. RESULTS: No adverse events were observed. Statistical analysis showed that hard stools and artificial defecation reduced, and that their effect sizes were significant (Tau = -0.48, P < 0.01; Tau = -0.53, P < 0.01). Even the amounts of stimulant laxative and glycerin enema reduced, and their effect sizes were significant (Tau = -0.56, P < 0.01; Tau = -0.34, P = 0.04). CONCLUSIONS: Thus, defecation care based on ultrasonographic assessment by nurses in home-care settings is safe and effective for improving constipation symptoms and reducing laxative use. Geriatr Gerontol Int 2020; ••: ••-••.

Experience that Much Work Produces Many Reinforcers Makes the Sunk Cost Fallacy in Pigeons: A Preliminary Test.

The sunk cost fallacy is one of the irrational choice behaviors robustly observed in humans. This fallacy can be defined as a preference for a higher-cost alternative to a lower-cost one after previous investment in a higher-cost alternative. The present study examined this irrational choice by exposing pigeons to several types of trials with differently illuminated colors. We prepared three types of non-choice trials for experiencing different outcomes after presenting same or different colors as alternatives and three types of choice trials for testing whether pigeons demonstrated irrational choice. In non-choice trials, animals experienced either of the following: (1) no reinforcement after the presentation of an unrelated colored stimulus to the alternatives used in the choice situation, (2) no reinforcement after investment in the lower-cost alternative, or (3) reinforcement or no reinforcement after investment in the higher-cost alternative. In choice trials, animals were required to choose in the following three situations: (A) higher-cost vs. lower-cost alternatives, (B) higher-cost vs. lower-cost ones after some investment in the higher-cost alternative, and (C) higher-cost vs. lower-cost alternatives after the presentation of an unrelated colored stimulus. From the definition of the sunk cost fallacy, we assumed that animals would exhibit this fallacy if they preferred the higher-cost alternative in situation (B) compared with (A) or (C). We made several conditions, each of which comprised various combinations of three types of non-choice trials and tested their preference in three choice trials. Pigeons committed the sunk cost fallacy only in the condition that contained non-choice trials (3), i.e., pigeons experienced reinforcement after investing in the higher-cost alternative. This result suggests that sunk cost fallacy might be caused by the experiences of reinforcement after investing in the higher-cost alternative.

Hepatitis B virus X stimulates redox signaling through activation of ataxia telangiectasia mutated kinase.

Hepatitis B virus X (HBX) protein plays a crucial role in carcinogenesis, but its mechanism is unclear. The involvement of ataxia telangiectasia mutated (ATM) kinase in the enhanced redox system was investigated by examining the phosphorylation level of ATM in HBX gene-transfected cells and in transgenic mice following redox system manipulation by treatment with hydrogen peroxide (H2O2) or antioxidant. Western blotting and immunostaining showed that phospho-ATM was significantly increased by HBX both in vitro (3.2-fold; p<0.05) and in vivo (4-fold; p<0.05), and this effect was abrogated by antioxidant treatment. The level of PKC-δ in HBX-expressing cells was increased 3.5-fold compared to controls. Nuclear localized NF-E2-related factor 2 (Nrf2) was increased in HBX-expressing cells exposed to H2O2, but remained at lower levels after the treatment with rottlerin, KU55933, or caffeine. The levels of anti-oxidant molecules were increased in HBX expressing cells and in transgenic mice, indicating that HBX stimulates the Nrf2-mediated redox system. The levels of intracellular reactive oxygen species (ROS) were significantly increased in HBX-expressing cells treated with hydrogen peroxide in the presence of ATM inhibitor KU55933 or caffeine. Treatment of HBX-expressing cells with KU55933 or caffeine before the exposure to H2O2 increased the ratio of cell apoptosis to 33±4% (p<0.05) and 22±4% (p<0.05), respectively. Collectively, HBX stimulates the ATM-mediated PKC-δ/Nrf2 pathway, and maintains the enhanced activity of the redox system. Therefore, manipulating ATM kinase activity might be a useful strategy for treating HBX-induced carcinogenesis.

Valproic acid overcomes transforming growth factor-ß-mediated sorafenib resistance in hepatocellular carcinoma.

Sorafenib is a multi-kinase inhibitor approved for hepatocellular carcinoma, but rarely causes tumor regression in patients with chronic liver diseases. To investigate whether growth factor-mediated signaling is involved in sorafenib resistance, HepG2 and PLC/PRF/5 hepatoma cells were exposed to epidermal growth factor (EGF), hepatocyte growth factor (HGF) or transforming growth factor-ß (TGF-ß) prior to treatment with sorafenib. Furthermore, to identify an effective combination treatment with sorafenib, growth factor-sensitized cells were treated with sorafenib alone or in combination with celecoxib, lovastatin or valproic acid (VPA). Trypan blue staining and Annexin V assays showed that the cytotoxic effect of sorafenib was inhibited by 15-54% in cells sensitized to TGF-ß (P<0.05). Western blotting analysis showed that TGF-ß significantly activated extracellular signal-regulated kinase (ERK)-mediated AKT signaling, and sorafenib failed to suppress both ERK and AKT in TGF-ß-sensitized cells. The decreased anti-tumor effect of sorafenib was rescued by chemical inhibition of ERK and AKT. When TGF-ß-sensitized cells were treated with sorafenib plus VPA, the levels of phosphorylated ERK and AKT were considerably suppressed and the numbers of dead cells were increased by 3.7-5.7-fold compared with those exposed to sorafenib alone (P<0.05). Moreover, low dose sorafenib-induced cell migration was effectively suppressed by combination treatment with sorafenib and VPA. Collectively, TGF-ß/ERK/AKT signaling might play a critical role in sorafenib resistance in hepatoma cells, and combination treatment with VPA may be effective against this drug resistance.

p27 Is a critical prognostic biomarker in non-alcoholic steatohepatitis-related hepatocellular carcinoma.

Non-alcoholic steatohepatitis (NASH) is a recently identified chronic liver disease, which progresses to liver cirrhosis and hepatocellular carcinoma (HCC). As the number of patients studied to date has been limited, clinically useful prognostic biomarkers of NASH-related HCC have not been available. In this study, we investigated the status of a cell-cycle regulator, p27, in NASH-related HCC. p27 has been regarded as a prognostic factor in various types of cancer patients. A total of 22 cases with NASH-related HCC were analyzed for p27 protein expression, and phosphorylation at threonine 157 (T157) and serine 10 (S10) by immunohistochemical analysis. The correlation of p27 with tumor characteristics, disease-free survival (DFS), and overall survival was analyzed. p27 expression was decreased in 13 HCCs (59%), and was significantly correlated with enlarged tumor size (p = 0.01) and increased cell proliferation (p < 0.01). Phospho-p27 at T157 and S10 was detected in four (18%) and seven (32%) cases, respectively, and patients positive for phospho-p27 (S10) showed reduced DFS (hazard ratio 7.623, p = 0.016) by univariate analysis. Further studies with more patients are required to verify the usefulness of p27 as a biomarker for predicting tumor recurrence in NASH patients.

Effects of rapamycin on granulation formation in response to centrally doubled coiled stents as a tracheal substitute.

INTRODUCTION: In experiments involving tracheal wall defects in rabbits, metallic coil stents inevitably induce granulation formation in the defects. We examined the involvement of the mammalian target of rapamycin (mTOR) signaling pathway in granulation formation and examined the effects of rapamycin. METHODS: The anterior half of the tracheal wall was removed for a longitudinal length of six tracheal rings. Metallic coils were placed into the tracheal lumen through a wall defect. The rabbits were sacrificed two months after undergoing an endoscopic examination, and the granulation tissue in the tracheal defects was removed for a Western blot analysis and immunohistochemical analysis. Rapamycin (0.5 mg kg(-1) day(-1)) was administered three times per week intramuscularly. The data were expressed as the relative expression versus the expression of actin. RESULTS: The level of mTOR phosphorylation in the resected trachea was 0.72±0.45, and it significantly increased in the granulation tissue to 11.6±5.2, with concomitant increases in the phosphorylation levels of p70S6K and S6RP in all five rabbits. Although the systemic administration of rapamycin significantly decreased the levels of phosphorylated mTOR to 4.0±2.4 in the five treated rabbits, the clinical outcomes were unsatisfactory. Three of the five treated rabbits exhibited signs of wound complications, and wet granulation tissue that caused respiratory symptoms was found inside and outside of the coils in four rabbits. CONCLUSIONS: Although rapamycin effectively reduced the mTOR activity in the granulation tissue, the granulation formation process seemed to be disturbed, most likely owing to the immunosuppressive effects of rapamycin.

Clinical significance of cell cycle inhibitors in hepatocellular carcinoma.

It is well accepted that cell cycle regulators are strongly implicated in the progression of cancer development. p16 and p27 are potent cyclin-dependent kinase (CDK) inhibitors involved in G1 phase progression, and are regarded as adverse prognostic biomarkers for various types of cancers. It has been reported that the main mechanism for p16 inactivation is aberrant DNA methylation, while p27 is exclusively inactivated by proteasome-mediated protein degradation. We have found that p27 is decreased in around half of hepatocellular carcinomas (HCCs), and in some cases p27 is inactivated by inappropriate interaction with cyclin D1/CDK4 complexes. In such cases, p16 is concomitantly inactivated through DNA methylation. Taking into consideration the complex interaction between p16 and p27, a comprehensive analysis including p16 and p27 would be useful for predicting the prognosis of HCC patients.

Mycotoxins are conventional and novel risk biomarkers for hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a common malignant disease with poor prognosis. To improve the clinical outcome, early diagnosis of HCC arising from nonviral agents and hepatitis virus is important. Among several etiological factors, mycotoxins defined as carcinogens by the International Agency for Research in Cancer (IARC) might be one of the critical risk factors for nonviral HCC. Aflatoxin B1 is the most well-known carcinogenic mycotoxin for HCC, but the role of the other types of mycotoxin remains unclear. Several studies have reported that a chromatographic separation technique based on high-performance liquid chromatography can successfully detect the concentration of mycotoxins in plasma. Recently, serum level of ochratoxin A (OTA), a widely distributed mycotoxin classified as Group 2B by IARC, was evaluated in HCC patients in Egypt. The results suggested that serum OTA levels might be a good biomarker for HCC. In this article, we review recent studies of OTA, and discuss its possible significance as a biomarker of HCC.

Hepatitis B virus X induces cell proliferation in the hepatocarcinogenesis via up-regulation of cytoplasmic p21 expression.

BACKGROUND: Hepatitis B virus X protein (HBx) has been shown to induce hepatocarcinogenesis by disrupting the functions of intracellular molecules. Cyclin-dependent kinase inhibitor p21 (Cip1/WAF1), known as a tumour-suppressor gene, has been reported to have paradoxical function, that is, acting as an oncogene, particularly when expressed in the cytoplasm. The effects of HBx on the expression and function of p21 also remain controversial. AIMS: We attempted to investigate the role of HBx in the hepatocarcinogenic process, focusing on the association with this paradoxical function of p21. The results obtained were further verified with experiments using the antihepatocarcinogenic action of interferon (IFN)-ß. METHODS: HBx transgenic mice (Xg) and HBx-transfected hepatoma cell lines were used. Intracellular localization of p21 was determined by Western blot analysis and immunofluorescence. RESULTS: Xg and HBx-transfected cells exhibited increased expression of p21. Up-regulation of p21 was positively correlated with the expression of cyclin D1 and inactive phosphorylation of retinoblastoma protein (pRb). These HBx-induced cell proliferative responses were cancelled by knockdown of p21, which resulted in growth reduction in HBx-expressing cells, suggesting the oncogenic properties of HBx-induced p21. HBx induced accumulation of p21 in the cytoplasm, and activation of PKCα was involved. Finally, IFN-ß-treated Xg liver, as well as hepatoma cells, showed a shift of cytoplasmic p21 to the nucleus, accompanied by the abrogation of HBx-induced oncogenic modulation. CONCLUSIONS: Our results suggest that HBx induces hepatocarcinogenesis via PKCα-mediated overexpression of cytoplasmic p21 and IFN-ß suppressed these molecular events by shifting p21 to the nucleus.

DNA damage sensor γ -H2AX is increased in preneoplastic lesions of hepatocellular carcinoma.

BACKGROUND: Phosphorylated histone H2AX ( γ -H2AX) is a potential regulator of DNA repair and is a useful tool for detecting DNA damage. To evaluate the clinical usefulness of γ -H2AX in hepatocellular carcinoma (HCC), we measured the level of γ -H2AX in HCC, dysplastic nodule, and nontumorous liver diseases. METHODS: The level of γ -H2AX was measured by immunohistochemistry in fifty-eight HCC, 18 chronic hepatitis, 22 liver cirrhosis, and 19 dysplastic nodules. Appropriate cases were also examined by fluorescence analysis and western blotting. results: All cases with chronic liver disease showed increased levels of γ -H2AX expression. In 40 (69.9%) of 58 cases with HCC, the labeling index (LI) of γ -H2AX was above 50% and was inversely correlated with the histological grade. Mean γ -H2AX LI was the highest in dysplastic nodule (74.1 ± 22.1%), which was significantly higher than HCC (P < 0.005). Moreover, γ -H2AX was significantly increased in nontumorous tissues of HCC as compared with liver cirrhosis without HCC (62.5 ± 24.7%, from 5.1 to 96.0%, P < 0.005). CONCLUSIONS: γ -H2AX was increased in the preneoplastic lesions of HCC and might be a useful biomarker for predicting the risk of HCC.

P21-activated kinase-2 is a critical mediator of transforming growth factor-ß-induced hepatoma cell migration.

BACKGROUND AND AIM: Transforming growth factor-ß (TGF-ß) has been shown to play a central role in the promotion of cell motility, but its functional mechanism has remained unclear. With the aim of investigating the diagnostic and treatment modalities for patients with hepatocellular carcinoma (HCC), the signaling pathway that may contribute to TGF-ß-mediated cell invasion in hepatoma cells was evaluated. METHODS: Three hepatoma cell lines, HepG2, PLC/PRF/5, and HLF, were treated with TGF-ß, and the involvement of the non-canonical TGF-ß pathway was analyzed by cell migration assays. HepG2 cells were treated with a p21-activated kinase-2 (PAK2)-targeting small interfering RNA and analyzed for their cell motility. The relationships between the PAK2 status and the clinicopathological characteristics of 62 HCC patients were also analyzed. RESULTS: The cell migration assays showed that Akt is a critical regulator of TGF-ß-mediated cell migration. Western blotting analyses showed that TGF-ß stimulated Akt and PAK2 in all three hepatoma cell lines, and phosphorylated PAK2 was blocked by Akt inhibitor. Suppression of PAK2 expression by small interfering RNA resulted in increased focal adhesions with significantly repressed cell migration in the presence of TGF-ß. Clinicopathological analyses showed that the phosphorylation level of PAK2 was closely associated with tumor progression, metastasis, and early recurrence of HCC. CONCLUSIONS: PAK2 may be a critical mediator of TGF-ß-mediated hepatoma cell migration, and may represent a potential target for the treatment of HCC.

Blockade of ataxia telangiectasia mutated sensitizes hepatoma cell lines to sorafenib by interfering with Akt signaling.

Sorafenib is a multi-kinase inhibitor applicable to hepatocellular carcinoma (HCC), but its limited therapeutic effects are a major problem to be solved. Here, we show that blockade of ataxia telangiectasia mutated (ATM) improves the antitumor effects of sorafenib. When hepatoma cell lines HepG2 and PLC/PRF/5 were treated with sorafenib plus ATM small inhibitory RNAs, ATM inhibitor KU55933 or caffeine, Akt signaling was suppressed and the cytotoxic effects were significantly potentiated. Moreover, ATM inhibition effectively suppressed the sorafenib-induced cell migration. Taken together, manipulation of ATM activity might be a useful strategy for improving sorafenib treatment of HCC.