E-commerce channel management on the manufacturers’ side: ongoing debates and future research pathways

Since the beginning of the 2000s, online commerce has been gradually taking over and shaping the global marketplace. This has led several scholars to study the phenomenon from different angles, from consumer habits to privacy risks to related technological innovations. However, only recently has a branch of literature addressing the online channel management phenomenon from the manufacturers’ perspective emerged. This rapidly expanding literature strand remains rather fragmented, raising the need for a systematic literature review to comprehensively structure and discuss it. This study, accordingly, proposes a systematic literature review on online channel management from the manufacturers’ perspective. Firstly, it provides relevant bibliometric insights into the ongoing research on the topic. Secondly, applying the bibliographic coupling methodology individuates 92 interconnected contributions published by 31 December 2021. Three different, albeit interconnected, thematic clusters are discovered and reviewed, revealing their focus on (a) strategic marketing issues around manufacturervsretailer conflict, (b) pricing policies and trade-offs among pricevsservices, and (c) operational interactions and strategies between supply chain members. Finally, after a systematic literature review the authors develop thirteen original research propositions concerning new research pathways and theoretical advancements to be designed and implemented.

Using the UTAUT model to analyze user intention to accept electronic payment systems in Serbia

This study applies The Unified Theory of Acceptance and Use of Technology (UTAUT) to explain the acceptance of electronic payment systems in Serbia. We used extended model that incorporates several external variables, such as perceived security, trust, privacy, convertibility and financial costs, along with basic UTAUT predictors. The sample comprised of 457 respondents. We applied structural equation modelling to develop the model and draw conclusions. The results showed that performance expectancy, perceived security, trust and social influence had strong positive effects on behavioral intention. Conversely, we found behavioral intention, convertibility and financial costs to be significant drivers of user behavior. We consider the inclusion of convertibility in the model and proving its significance to be the main practical implications of our research, and also suggest to be considered as a factor in models designed for countries with low purchasing power of national currency.

Cell death biomarker M65 is a useful indicator of liver inflammation and fibrosis in chronic hepatitis B: A cross-sectional study of diagnostic accuracy

Cell death markers, M65 and M30, have been suggested to be sensitive markers of liver inflammation and fibrosis in nonalcoholic fatty liver disease and chronic hepatitis C. Our aim was to investigate whether these markers were useful in diagnosing liver inflammation and fibrosis in chronic hepatitis B (CHB).We examined 186 patients with CHB; 18 sex- and age-matched healthy subjects were controls. The blood samples were collected from CHB patients within 1 week before or after liver biopsy. According to METAVIR score system, liver inflammation was graded from A0 to A3, and fibrosis from F0 to F4.Serum M65 and M30 levels were in parallel with the grades of liver inflammation. M65, not M30, increased significantly in patients with severe inflammation and normal alanine aminotransferase. M65 is one of the independent predictors of severe liver inflammation (≥A2). The levels of M65 and M30 levels significantly increased in parallel with the degree of inflammation in F1 patients, whereas they showed no statistical difference between different stages of fibrosis in A1 patients.Serum M65 is a useful indicator of liver inflammation in CHB patients. Serum M65, not M30, is valuable in the grading of liver fibrosis.

Intraperitoneal administration of apigenin in liver ischemia/reperfusion injury protective effects

BACKGROUND/AIMS

Hepatic injury caused by ischemia/reperfusion (I/R) is a clinical problem associated with major liver surgery. Among other flavonoids, apigenin has shown a promising effect on I/R cases. In this study, we have investigated the effects of apigenin after liver I/R injury in rats.

MATERIALS AND METHODS

Forty eight rats were randomized into the following eight groups: (1) Control-sham group: rats subjected to the surgical procedure, except for liver I/R; (2) DMSO group: rats subjected to surgery, except for liver I/R given the apigenin solvent dimethyl-sulfoxide intraperitoneally; (3) C60 group; (4) C120 group; (5) C240 group: rats underwent liver ischemia for 45 min followed by reperfusion for 60 min, 120 min, and 240 min; (6) AP60 group; (7) AP120 group; (8) AP240 group: rats underwent liver ischemia for 45 min, and then given apigenin (5 mg) intraperitoneally followed by reperfusion for 60 min, 120 min, and 240 min. Reverse transcription polymerase chain reaction was performed on liver tissues to measure BCL-2/BAX expression, enzyme-linked immunosorbent assay to measure M30/M65 and ICAM-1. Immunohistochemistry was used to identify M30 biomarker in liver tissues.

STATISTICAL ANALYSIS

Quantitative variables were tested by Kolmogorov-Smirnov test, repeated measures analysis of variance/Friedman test. Gene levels were assessed by Student's t-test/Mann-Whitney U-test.

RESULTS

BCL-2 levels were significantly higher in I/R apigenin groups than in I/R control groups. BAX levels were lower in the AP240 group than in C240 group. Prolongation of reperfusion resulted in increased activation of M30. ICAM-1 levels were lower in the AP240 group than in C240 group.

CONCLUSIONS

Apigenin seems to inhibit the process of apoptosis and ameliorate the hepatic I/R injury.

Keratins: Biomarkers and modulators of apoptotic and necrotic cell death in the liver

Keratins, formerly known as cytokeratins, are the major epithelial-specific subgroup of intermediate filament proteins. Adult hepatocytes express keratin polypeptides 8 and 18 (K8/K18), whereas cholangiocytes express K8/K18 and keratins 7 and 19 (K7/K19). Keratins function primarily to protect hepatocytes from apoptosis and necrosis, which was revealed using several genetic mouse models. This cytoprotective function was further clarified by the identification of natural human keratin variants that are normally silent, but become pathogenic by predisposing their carriers to apoptosis during acute or chronic liver injury mediated by toxins, virus infection, or metabolic stress. During apoptosis, caspases cleave K18 and K19 at conserved aspartates (human K18/K19: (235) Val-Glu-Val-Asp(↓) ) and K18 at a unique aspartate (human K18: (394) Asp-Ala-Leu-Asp(↓) ), with the latter exposed epitope becoming recognized by the M30 antibody in blood and tissues. Additional K18-containing protein backbone epitopes are detected using the M6 and M5 (termed M65) antibodies. Intact K18 and its associated fragments, which are released into blood during apoptosis and necrosis in various diseases, have been analyzed by enzyme-linked immunosorbent assay using the M30/M65 antibodies or their signal ratios. Furthermore, M30/M65 levels have been used as diagnostic and prognostic biomarkers in acute and chronic liver diseases, including nonalcoholic steatohepatitis and acute liver failure. Other keratin biomarkers include K8/K18/K19-related tissue polypeptide antigen, K18-related tissue polypeptide-specific antigen, and K19-related CYFRA-21-1, which have been evaluated mostly in patients with epithelial tumors.

CONCLUSION

Keratins and their fragments are released into blood during liver and other epithelial tissue injury. The epithelial specificity of K18/K19, epitope unmasking upon caspase digestion, keratin abundance, and relative keratin stability render them useful biomarkers for hepatocyte and cholangiocyte apoptosis and necrosis. However, the precise biochemical nature and release mechanism of circulating keratins remain unknown. (Hepatology 2016;64:966-976).

Propofol or sevoflurane anaesthesia does not affect hepatic integrity as assessed by the M30 & M65 cell death markers & liver enzymes

BACKGROUND & OBJECTIVES

General anaesthetics may induce apoptosis. The pro-apoptotic/necrotic markers M30 (caspase-cleaved cytokeratin-18) and M65 (intact cytokeratin-18) have been used to identify early apoptosis in liver disease. The aim of this study was to detect the effect of propofol and sevoflurane anaesthesia on these markers and blood transaminase levels in female patients undergoing elective surgery.

METHODS

Sixty-seven women undergoing mastectomy or thyroidectomy under general anaesthesia were randomly allocated to the propofol or sevoflurane groups. Venous blood samples for measuring the apoptotic and necrotic markers M30 and M65 as well as for measuring the alanine aminotransferase (ALT) and the aspartate aminotransferase (AST) liver enzymes were collected before induction of anaesthesia, immediately after completion of surgery, and 24 and 48 h postoperatively.

RESULTS

The M30 values preoperatively and 0, 24 and 48 h postoperatively were 280±229, 300±244, 267±198 and 254±189 U/l in the propofol group and 237±95, 242±109, 231±94 and 234±127 U/l in the sevoflurane group, respectively. The M30 values did not differ within or between the groups. The M65 levels at the same time intervals were 470±262, 478±271, 456±339 and 485±273 in the propofol group and 427±226, 481±227, 389±158 and 404±144 U/l in the sevoflurane group, respectively. No significant changes were found in the M65 either within or between the propofol and the sevoflurane groups. The ALT and AST levels did not change at these time intervals.

INTERPRETATION & CONCLUSIONS

Under the present study design propofol or sevoflurane anaesthesia did not induce apoptosis or affected the liver function as assessed by the M30, M65 markers and liver enzymes in patients undergoing mastectomy or thyroidectomy under general anaesthesia.

Character and temporal evolution of apoptosis in acetaminophen-induced acute liver failure*

OBJECTIVE

To evaluate the role of hepatocellular and extrahepatic apoptosis during the evolution of acetaminophen-induced acute liver failure.

DESIGN AND SETTING

A prospective observational study in two tertiary liver transplant units.

PATIENTS

Eighty-eight patients with acetaminophen-induced acute liver failure were recruited. Control groups included patients with nonacetaminophen-induced acute liver failure (n = 13), nonhepatic multiple organ failure (n = 28), chronic liver disease (n = 19), and healthy controls (n = 11).

MEASUREMENTS

Total and caspase-cleaved cytokeratin-18 (M65 and M30) measured at admission and sequentially on days 3, 7, and 10 following admission. Levels were also determined from hepatic vein, portal vein, and systemic arterial blood in seven patients undergoing transplantation. Protein arrays of liver homogenates from patients with acetaminophen-induced acute liver failure were assessed for apoptosis-associated proteins, and histological assessment of liver tissue was performed.

MAIN RESULTS

Admission M30 levels were significantly elevated in acetaminophen-induced acute liver failure and non-acetaminophen induced acute liver failure patients compared with multiple organ failure, chronic liver disease, and healthy controls. Admission M30 levels correlated with outcome with area under receiver operating characteristic of 0.755 (0.639-0.885, p < 0.001). Peak levels in patients with acute liver failure were seen at admission then fell significantly but did not normalize over 10 days. A negative gradient of M30 from the portal to hepatic vein was demonstrated in patients with acetaminophen-induced acute liver failure (p = 0.042) at the time of liver transplant. Analysis of protein array data demonstrated lower apoptosis-associated protein and higher catalase concentrations in acetaminophen-induced acute liver failure compared with controls (p < 0.05). Explant histological analysis revealed evidence of cellular proliferation with an absence of histological evidence of apoptosis.

CONCLUSIONS

Hepatocellular apoptosis occurs in the early phases of human acetaminophen-induced acute liver failure, peaking on day 1 of hospital admission, and correlates strongly with poor outcome. Hepatic regenerative/tissue repair responses prevail during the later stages of acute liver failure where elevated levels of M30 are likely to reflect epithelial cell death in extrahepatic organs.

Considerations for the use of plasma cytokeratin 18 as a biomarker in pancreatic cancer

BACKGROUND

Enzyme-linked immunoassays of full-length (M65) and/or caspase-cleaved (M30) cytokeratin 18 (CK18) released from epithelial cells undergoing necrosis and/or apoptosis, respectively, may have prognostic or predictive biomarker utility in a range of solid tumour types. Characterisation of baseline levels of circulating full length and cleaved CK18 specifically in patients with pancreatic cancer.

METHODS

Plasma samples from 103 patients with pancreatic cancer stored at -80 degrees C were assayed for M65 and M30 levels. The median (inter-quartile range (IQR)) duration of plasma storage was 34 (23-57) months. Patients with metastatic disease (n=19) were found to have greater median (IQR) M65 levels (1145 (739-1698) U l(-1)) compared with the locally advanced (n=20; 748 (406-1150) U l(-1)) and resected (n=64; 612 (331-987) U l(-1)) patients (P=0.002). Elevated M65 levels were associated with poorer overall survival on univariate (P<0.001) but not multivariate (P=0.202) analysis. M65 concentrations also exhibited significant associations with concurrent serum-bilirubin levels (P<0.001) and the duration of plasma storage (P<0.001).

CONCLUSIONS

Baseline plasma CK18 levels in pancreatic cancer are affected by the presence of obstructive jaundice and prolonged plasma storage. Clinical biomarker studies utilising serial CK18 levels are warranted in pancreatic cancer, provided consideration is given to these potentially confounding factors.