Acute amebic appendicitis in early pregnancy.

Parasitic infections of the intestine are a major health problem, which is found more prevalent in developing countries such as India. They are one of the important causes of morbidity and mortality among people all over the world. Acute amoebic appendicitis is a rare entity. We came across a case of acute appendicitis in a young pregnant woman, which revealed colonies of Entamoeba histolytica trophozoites in the mucosal epithelium and submucosal layer of the appendix with marked evidence of acute appendicitis. This report highlights acute appendicitis of amoebic origin and emphasises the importance of thorough examination of the appendix at various levels during histopathology and about the combined treatment of appendicectomy combined with antimicrobials as the treatment of choice. Appendicectomy removes the focus of infection, and antimicrobials reduce the incidence of septic complications.

An endogenous DNA adduct as a prognostic biomarker for hepatocarcinogenesis and its prevention by Theaphenon E in mice.

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide, mainly because of its poor prognosis. A valid mechanism-based prognostic biomarker is urgently needed. γ-hydroxy-1,N2 -propanodeoxyguanosine (γ-OHPdG) is an endogenously formed mutagenic DNA adduct derived from lipid peroxidation. We examined the relationship of γ-OHPdG with hepatocarcinogenesis in two animal models and its potential role as a prognostic biomarker for recurrence in HCC patients. Bioassays were conducted in xeroderma pigmentosum group A knockout mice and diethylnitrosamine-injected mice, both prone to HCC development. γ-OHPdG levels in the livers of these animals were determined. The effects of antioxidant treatments on γ-OHPdG and hepatocarcinogenesis were examined. Using two independent sets of HCC specimens from patients, we examined the relationship between γ-OHPdG and survival or recurrence-free survival. γ-OHPdG levels in liver DNA showed an age-dependent increase and consistently correlated with HCC development in all three animal models. Theaphenon E treatment significantly decreased γ-OHPdG levels in the liver DNA of xeroderma pigmentosum group A knockout mice and remarkably reduced HCC incidence in these mice to 14% from 100% in the controls. It also effectively inhibited HCC development in the diethylnitrosamine-injected mice. Using clinical samples from two groups of patients, our study revealed that higher levels of γ-OHPdG are strongly associated with low survival (P < 0.0001) and low recurrence-free survival (P = 0.007). CONCLUSION: These results support γ-OHPdG as a mechanism-based, biologically relevant biomarker for predicting the risk of HCC and its recurrence. (Hepatology 2018;67:159-170).

Biochemical and cell biological assays to identify and characterize DNA helicase inhibitors.

The growing number of DNA helicases implicated in hereditary disorders and cancer indicates that this particular class of enzymes plays key roles in genomic stability and cellular homeostasis. Indeed, a large body of work has provided molecular and cellular evidence that helicases act upon a variety of nucleic acid substrates and interact with numerous proteins to enact their functions in replication, DNA repair, recombination, and transcription. Understanding how helicases operate in unique and overlapping pathways is a great challenge to researchers. In this review, we describe a series of experimental approaches and methodologies to identify and characterize DNA helicase inhibitors which collectively provide an alternative and useful strategy to explore their biological significance in cell-based systems. These procedures were used in the discovery of biologically active compounds that inhibited the DNA unwinding function catalyzed by the human WRN helicase-nuclease defective in the premature aging disorder Werner syndrome. We describe in vitro and in vivo experimental approaches to characterize helicase inhibitors with WRN as the model, anticipating that these approaches may be extrapolated to other DNA helicases, particularly those implicated in DNA repair and/or the replication stress response.

Inhibition of helicase activity by a small molecule impairs Werner syndrome helicase (WRN) function in the cellular response to DNA damage or replication stress.

Modulation of DNA repair proteins by small molecules has attracted great interest. An in vitro helicase activity screen was used to identify molecules that modulate DNA unwinding by Werner syndrome helicase (WRN), mutated in the premature aging disorder Werner syndrome. A small molecule from the National Cancer Institute Diversity Set designated NSC 19630 [1-(propoxymethyl)-maleimide] was identified that inhibited WRN helicase activity but did not affect other DNA helicases [Bloom syndrome (BLM), Fanconi anemia group J (FANCJ), RECQ1, RecQ, UvrD, or DnaB). Exposure of human cells to NSC 19630 dramatically impaired growth and proliferation, induced apoptosis in a WRN-dependent manner, and resulted in elevated γ-H2AX and proliferating cell nuclear antigen (PCNA) foci. NSC 19630 exposure led to delayed S-phase progression, consistent with the accumulation of stalled replication forks, and to DNA damage in a WRN-dependent manner. Exposure to NSC 19630 sensitized cancer cells to the G-quadruplex-binding compound telomestatin or a poly(ADP ribose) polymerase (PARP) inhibitor. Sublethal dosage of NSC 19630 and the chemotherapy drug topotecan acted synergistically to inhibit cell proliferation and induce DNA damage. The use of this WRN helicase inhibitor molecule may provide insight into the importance of WRN-mediated pathway(s) important for DNA repair and the replicational stress response.

Plant-based diets and postprandial hyperkalemia.

This Letter to the Editor is a response to St-Jules and Fouque and their interpretation of postprandial hyperkalemia, especially regarding plant-based diets. Based on the reviewed literature review, potassium kinetic studies cited by the authors include only 1 study with a food-based intervention that actually showed reduced postprandial hyperkalemia with plant-based diets. The remainder of the studies used potassium salts or supplements that behave differently compared with whole plant foods. As such, we recommend avoiding restriction of whole plant foods in patients with chronic kidney disease when solely based on the theoretical risk of postprandial hyperkalemia.

Topiramate-induced acute eosinophilic pneumonia.

A man in his 40s with a known history of alcohol dependence syndrome was admitted with presenting symptoms of alcohol withdrawal. During his admission, he developed breathlessness, cough and wheezing. Investigations revealed raised absolute eosinophil count and serum IgE levels. Chest imaging showed ill-defined opacities and fibreoptic bronchoscopy with bronchoalveolar lavage confirmed eosinophilic pneumonia. Extensive workup for the cause of eosinophilia was negative. The patient's medicines were reviewed, and it was realised that the onset of eosinophilia occurred after starting topiramate for an alcohol withdrawal seizure. The drug was stopped, leading to the complete resolution of symptoms and radiological abnormalities. This case highlights the importance of considering drug-induced causes of eosinophilic pneumonia.

Association of Neutrophil-Lymphocyte Ratio and Red Blood Cell Distribution Width with Poor Outcome in Pediatric Cardiac Surgery - A Retrospective Observational Study.

BACKGROUND: Neutrophil-lymphocyte ratio (NLR) is a valuable indicator for evaluating inflammatory response and red blood cell distribution width (RBDW), a routinely available biomarker of likely erythropoietic dysfunction, which may be associated with adverse outcomes after cardiac surgery. This study aimed to investigate the association between these two readily available haematological parameters, with the poor outcomes in paediatric patients undergoing cardiac surgery. METHODS: A comprehensive review of medical records for paediatric patients who underwent cardiac surgery at our tertiary care centre between April 2022 and June 2023 was carried out. RBDW and NLR values were collected from complete blood count reports obtained on admission to the ICU. Demographic data, surgical details, and postoperative complications were also recorded. A receiver operating characteristic (ROC) curve and multivariable logistic regression were applied to identify the prognosis performance of preoperative NLR and RBDW for poor outcomes. RESULTS: The study included 219 patients meeting the inclusion criteria of which a total of 90 (41%) children experienced at least one of the poor outcomes. Preoperative NLR (AUC=0.88, 95%CI 0.36-0.70, cut off- 4.2) and RBDW (AUC=0.88, 95%CI 0.39-0.73, cut off- 18.5%) showed prognostic significance in the perioperative period. CONCLUSION: This retrospective observational study highlights a significant association between elevated Red Blood Cell Distribution Width (RBDW) and Neutrophil Lymphocyte Ratio (NLR) values and poor outcomes in paediatric patients undergoing cardiac surgery. These readily available haematological parameters could serve as potential prognostic indicators for identifying patients at risk of poor outcomes.

Detection of γ-OHPdG in Circulating Tumor Cells of Patients With Hepatocellular Carcinoma as a Potential Prognostic Biomarker of Recurrence.

Background and Aims: Blood-based biomarkers for hepatocellular carcinoma (HCC) and its recurrence are lacking. We previously showed that hepatic γ-hydroxy-1,N 2 -propano-2'-deoxyguanosine (γ-OHPdG), an endogenous DNA adduct derived from acrolein by lipid peroxidation, increased during hepatocarcinogenesis. Additionally, higher hepatic γ-OHPdG from HCC patients after surgery were strongly associated with poor survival (P < .0001) and recurrence-free survival (P = .007) (Fu et al, Hepatology, 2018). These findings suggest that γ-OHPdG is a potential prognostic biomarker for HCC and its recurrence. To attain the goal of using γ-OHPdG as a biomarker in future preventive and therapeutic trials, we developed a blood-based method to detect γ-OHPdG in circulating liver tumor cells from HCC patient blood. Methods: We first established the specificity of anti-γ-OHPdG antibody by determining its dose-response in HepG2 cells treated with acrolein. Then, HepG2 cells in spiked blood of healthy volunteers and circulating tumor cells (CTCs) from 32 HCC patients were isolated using a RosetteSep CD45 Depletion Cocktail and Ficoll Paque. The HCC CTCs identified with anti-asialoglycoprotein receptor 1, a surface protein expressed solely in hepatocytes, were stained with an anti-γ-OHPdG antibody. The number of total HCC CTCs and γ-OHPdG-positive CTCs, as well as the staining intensity, were quantified using MetaMorph software. As an initial effort toward its clinical application, we also evaluated γ-OHPdG in CTCs from these patients along with certain clinical features. Results: The γ-OHPdG antibody specificity was demonstrated by an acrolein concentration-dependent increase of γ-OHPdG-positive HepG2 cells and the intensity of γ-OHPdG staining. The recovery of HepG2 cells from spiked blood was ∼50-60%, and the positivity rate of CTCs in blood from 32 patients with advanced HCC was 97%. The MetaMorph analysis showed a wide variation among patients in total number of CTCs, γ-OHPdG positivity, and staining intensity. Statistical analysis revealed that γ-OHPdG in CTCs of these patients appears to be associated with multifocality and poor differentiation. Conclusion: A blood-based method was developed and applied to HCC patients to evaluate the potential of γ-OHPdG in CTCs as a prognostic biomarker.

Molecular cloning, characterization, and engineering of xylitol dehydrogenase from Debaryomyces hansenii.

Because of its natural ability to utilize both xylose and arabinose, the halotolerant and osmotolerant yeast Debaryomyces hansenii is considered as a potential microbial platform for exploiting lignocellulosic biomass. To gain better understanding of the xylose metabolism in D. hansenii, we have cloned and characterized a xylitol dehydrogenase gene (DhXDH). The cloned gene appeared to be essential for xylose metabolism in D. hansenii as the deletion of this gene abolished the growth of the cells on xylose. The expression of DhXDH was strongly upregulated in the presence of xylose. Recombinant DhXdhp was expressed and purified from Escherichia coli. DhXdhp was highly active against xylitol and sorbitol as substrate. Our results showed that DhXdhp was thermo-sensitive, and except this, its biochemical properties were quite comparable with XDH from other yeast species. Furthermore, to make this enzyme suitable for metabolic engineering of D. hansenii, we have improved its thermotolerance and modified cofactor requirement through modelling and mutagenesis approach.