Dose-dependent effects of Dnmt3a in an inducible murine model of KrasG12D-driven leukemia.

DNMT3A mutations are frequently found in clonal hematopoiesis and a variety of hematologic malignancies, including acute myeloid leukemia. An assortment of mouse models have been engineered to explore the tumorigenic potential and malignant lineage bias due to loss of function of DNMT3A in consort with commonly comutated genes in myeloid malignancies, such as Flt3, Nras, Kras, and c-Kit. We employed several tamoxifen-inducible Cre-ERT2 murine model systems to study the effects of constitutively active KrasG12D-driven myeloid leukemia (Kras) development together with heterozygous (3aHet) or homozygous Dnmt3a deletion (3aKO). Due to the rapid generation of diverse nonhematologic tumors appearing after tamoxifen induction, we employed a transplantation model. With pretransplant tamoxifen induction, most Kras mice died quickly of T-cell malignancies regardless of Dnmt3a status. Using posttransplant induction, we observed a dose-dependent effect of DNMT3A depletion that skewed the leukemic phenotype toward a myeloid lineage. Specifically, 64% of 3aKO/Kras mice had exclusively myeloid disease compared with 36% of 3aHet/Kras and only 13% of Kras mice. Here, 3aKO combined with Kras led to increased disease burden, multiorgan infiltration, and faster disease progression. DOT1L inhibition exerted profound antileukemic effects in malignant 3aKO/Kras cells, but not malignant cells with Kras mutation alone, consistent with the known sensitivity of DNMT3A-mutant leukemia to DOT1L inhibition. RNAseq from malignant myeloid cells revealed that biallelic Dnmt3a deletion was associated with loss of cell-cycle regulation, MYC activation, and TNF⍺ signaling. Overall, we developed a robust model system for mechanistic and preclinical investigations of acute myeloid leukemia with DNMT3A and Ras-pathway lesions.

Preventive hepatology at AIIMS Rishikesh: Delivering comprehensive and integrated care for liver diseases in Northern state of India.

Globally, liver diseases accounts for 4% of all deaths. Annually, over 2 million deaths occur due to preventable causes of chronic liver diseases and liver cancer like fatty liver diseases (alcoholic or non alcoholic) and viral hepatitis B and C. The burden of chronic liver diseases are increasing, and the epidemiology and demographics of people affected by these diseases are changing. Policy changes, vaccination, screening, lifestyle changes and public health awareness is the key to curb down liver disaeses. To achieve the ultimate goal of reducing mortality and linkage to care for those who need specialized care for liver disease, it is vital to have dedicated preventive hepatology clinics in sync with existing liver or gastroenterology clinics at tertary care level.

Resin related enterocolitis: An underreported co-occurrence.

ABSTRACT: Medication resins are often encountered in gastrointestinal biopsy specimens of patients being treated for renal compromise. As important as they are for the electrolyte equilibrium of the patients, they often come with a cost of fatal but reversible damage to the gastrointestinal tract. This often manifests as inflammatory bowel disease in the affected individuals. This misleading manifestation coupled with the lack of patient history further masks resin-related colitis from a pathologist's eyes. Through this report, we convey how meticulous history-taking, representative endoscopic sampling, and recognition under the microscope are vital for timely reporting in conditions like this.

Transcriptomic profiling reveals a pronociceptive role for angiotensin II in inflammatory bowel disease.

ABSTRACT: Visceral pain is a leading cause of morbidity in inflammatory bowel disease (IBD), contributing significantly to reduced quality of life. Currently available analgesics often lack efficacy or have intolerable side effects, driving the need for a more complete understanding of the mechanisms causing pain. Whole transcriptome gene expression analysis was performed by bulk RNA sequencing of colonic biopsies from patients with ulcerative colitis (UC) and Crohn's disease (CD) reporting abdominal pain and compared with noninflamed control biopsies. Potential pronociceptive mediators were identified based on gene upregulation in IBD biopsy tissue and cognate receptor expression in murine colonic sensory neurons. Pronociceptive activity of identified mediators was assessed in assays of sensory neuron and colonic afferent activity. RNA sequencing analysis highlighted a 7.6-fold increase in the expression of angiotensinogen transcripts, Agt , which encode the precursor to angiotensin II (Ang II), in samples from UC patients ( P = 3.2 × 10 -8 ). Consistent with the marked expression of the angiotensin AT 1 receptor in colonic sensory neurons, Ang II elicited an increase in intracellular Ca 2+ in capsaicin-sensitive, voltage-gated sodium channel subtype Na V 1.8-positive sensory neurons. Ang II also evoked action potential discharge in high-threshold colonic nociceptors. These effects were inhibited by the AT 1 receptor antagonist valsartan. Findings from our study identify AT 1 receptor-mediated colonic nociceptor activation as a novel pathway of visceral nociception in patients with UC. This work highlights the potential utility of angiotensin receptor blockers, such as valsartan, as treatments for pain in IBD.

Checkpoint inhibitor hepatotoxicity: pathogenesis and management.

Immunotherapy, including immune checkpoint inhibitor (ICI) therapy, has been a paradigm shift in cancer therapeutics, producing durable cancer responses across a range of primary malignancies. ICI drugs increase immune activity against tumor cells, but may also reduce immune tolerance to self-antigens, resulting in immune-mediated tissue damage. ICI-associated hepatotoxicity usually manifests as hepatocellular enzyme elevation and may occur in 2%-25% of ICI-treated patients. Although ICI-associated hepatotoxicity is clinically and pathologically distinct from idiopathic autoimmune hepatitis, our understanding of its pathogenesis continues to evolve. Pending greater understanding of the pathophysiology, mainstay of management remains through treatment with high-dose corticosteroids. This approach works for many patients, but up to 30% of patients with high-grade hepatotoxicity may not respond to corticosteroids alone. Furthermore, atypical cholestatic presentations are increasingly recognized, and rare cases of fulminant hepatitis due to ICI hepatotoxicity have been reported. Optimal management for these challenging patients remains uncertain. Herein, we review the current understanding of pathogenesis of ICI-associated toxicities, with a focus on hepatotoxicity. Based on the existing literature, we propose evolving management approaches to incorporate strategies to limit excess corticosteroid exposure, and address rare but important presentations of cholestatic hepatitis and fulminant liver failure. Finally, as ICI hepatotoxicity frequently occurs in the context of treatment for advanced malignancy, we review the impact of hepatotoxicity and its treatment on cancer outcomes, and the overall safety of re-challenge with ICI, for patients who may have limited treatment options.

"De novo replication repair deficient glioblastoma, IDH-wildtype" is a distinct glioblastoma subtype in adults that may benefit from immune checkpoint blockade.

Glioblastoma is a clinically and molecularly heterogeneous disease, and new predictive biomarkers are needed to identify those patients most likely to respond to specific treatments. Through prospective genomic profiling of 459 consecutive primary treatment-naïve IDH-wildtype glioblastomas in adults, we identified a unique subgroup (2%, 9/459) defined by somatic hypermutation and DNA replication repair deficiency due to biallelic inactivation of a canonical mismatch repair gene. The deleterious mutations in mismatch repair genes were often present in the germline in the heterozygous state with somatic inactivation of the remaining allele, consistent with glioblastomas arising due to underlying Lynch syndrome. A subset of tumors had accompanying proofreading domain mutations in the DNA polymerase POLE and resultant "ultrahypermutation". The median age at diagnosis was 50 years (range 27-78), compared with 63 years for the other 450 patients with conventional glioblastoma (p < 0.01). All tumors had histologic features of the giant cell variant of glioblastoma. They lacked EGFR amplification, lacked combined trisomy of chromosome 7 plus monosomy of chromosome 10, and only rarely had TERT promoter mutation or CDKN2A homozygous deletion, which are hallmarks of conventional IDH-wildtype glioblastoma. Instead, they harbored frequent inactivating mutations in TP53, NF1, PTEN, ATRX, and SETD2 and recurrent activating mutations in PDGFRA. DNA methylation profiling revealed they did not align with known reference adult glioblastoma methylation classes, but instead had unique globally hypomethylated epigenomes and mostly classified as "Diffuse pediatric-type high grade glioma, RTK1 subtype, subclass A". Five patients were treated with immune checkpoint blockade, four of whom survived greater than 3 years. The median overall survival was 36.8 months, compared to 15.5 months for the other 450 patients (p < 0.001). We conclude that "De novo replication repair deficient glioblastoma, IDH-wildtype" represents a biologically distinct subtype in the adult population that may benefit from prospective identification and treatment with immune checkpoint blockade.

Dipyrromethane-diphosphine: the effect of meso substituents on the formation of nickel complexes and on their performance in the transfer hydrogenation of ketones.

Three dipyrromethane-diphosphine ligands containing phenyl (L1H2), ethyl (L2H2) and cyclohexyl (L3H2) groups at their meso positions and their nickel complexes were synthesized and structurally characterized. Treatment of Ph2C(C4H3N)2-1,9-(CH2PPh2)2 (L1H2) with [NiCl2(DME)] gave complex [NiCl2(κ2-P,P-L1H2)] 2a. Conversely, the analogous reactions of L2H2 and L3H2 with [NiCl2(DME)] showed a mixture of products containing both a pyrrolide nitrogen coordinated complex of type [Ni(κ4-P,N,N,P-L)] 3 without an exogenous base and a chelated complex of type 2a. In addition, all three ligands react with [NiCl2(DME)] in the presence of a strong base to give a complex of type 3. Furthermore, a novel binuclear Ni(0) complex bearing L1H2 was characterized by X-ray crystallography. Both complexes 2a and 3 (0.5 mol% of loading) catalyze the transfer hydrogenation of a series of aromatic and aliphatic ketones (20 substrates) to their corresponding secondary alcohols using iPrOH as a hydrogen source in the presence of KOH at 100 °C in 6 h. The kinetic trace of the catalytic reaction shows that the meso-phenyl substituted diphosphine coordinated nickel complexes perform better than the other two ligand coordinated nickel complexes.

KV7 but not dual small and intermediate KCa channel openers inhibit the activation of colonic afferents by noxious stimuli.

In numerous subtypes of central and peripheral neurons, small and intermediate conductance Ca2+-activated K+ (SK and IK, respectively) channels are important regulators of neuronal excitability. Transcripts encoding SK channel subunits, as well as the closely related IK subunit, are coexpressed in the soma of colonic afferent neurons with receptors for the algogenic mediators ATP and bradykinin, P2X3 and B2, highlighting the potential utility of these channels as drug targets for the treatment of abdominal pain in gastrointestinal diseases such as irritable bowel syndrome. Despite this, pretreatment with the dual SK/IK channel opener SKA-31 had no effect on the colonic afferent response to ATP, bradykinin, or noxious ramp distention of the colon. Inhibition of SK or IK channels with apamin or TRAM-34, respectively, yielded no change in spontaneous baseline afferent activity, indicating these channels are not tonically active. In contrast to its lack of effect in electrophysiological experiments, comparable concentrations of SKA-31 abolished ongoing peristaltic activity in the colon ex vivo. Treatment with the KV7 channel opener retigabine blunted the colonic afferent response to all applied stimuli. Our data therefore highlight the potential utility of KV7, but not SK/IK, channel openers as analgesic agents for the treatment of abdominal pain.NEW & NOTEWORTHY Despite marked coexpression of small (Kcnn1, Kcnn2) and intermediate (Kcnn4) conductance calcium-activated potassium channel transcripts with P2X3 (P2rx3) or bradykinin B2 (Bdkrb2) receptors in colonic sensory neurons, pharmacological activation of these channels had no effect on the colonic afferent response to ATP, bradykinin or luminal distension of the colon. This is in contrast to the robust inhibitory effect of the KV7 channel opener, retigabine.

Secukinumab-Induced Crohn's Disease in a Patient Treated for Juvenile Idiopathic Arthritis.

Juvenile idiopathic arthritis (JIA) is a common form of arthritis that occurs in children, typically with an onset before the age of 16 years. It can affect joints in any part of the body. As per the International League of Rheumatology, JIA is classified into systemic arthritis, oligoarthritis, extended oligoarthritis, polyarthritis (rheumatoid factor positive), polyarthritis (rheumatoid factor negative), enthesitis-related arthritis (ERA), juvenile psoriatic arthritis (JPsA), and other arthritis. JIA is treated with disease-modifying antirheumatic medications (DMARDs), which include both nonbiologic agents like methotrexate (MTX) and biologic agents like inhibitors of tumor necrosis factor-alpha, interleukin-1 (IL-1), IL-6, and T-cell co-stimulation modulators. As per recent studies, in December 2021, Secukinumab, an IL-17A inhibitor, is one of the most recent biologic agents approved for active ERA and JPsA. A few reports have suggested Secukinumab is related to new-onset inflammatory bowel diseases (IBDs). We present a case of a 20-year-old female who was being treated with Secukinumab for JIA, and six months into therapy, she developed symptoms suggestive of Crohn's disease (CD). The diagnosis was confirmed with colonoscopy, histopathology, and radiology results. Her symptoms completely resolved four weeks after discontinuing Secukinumab and oral steroid therapy. The efficacy and side effects of Secukinumab have been studied mainly on middle-aged populations who were being treated for psoriasis and ankylosing spondylitis (AS); however, there is limited literature on younger populations. With this case report, we would like to highlight the possible relationship between the development of IBD and Secukinumab therapy in the adolescent population and emphasize the importance of regular screening for IBD in this population.

Anatomical variations of cystic artery, cystic duct, and gall bladder and their associated intraoperative and postoperative complications: an observational study.

Anatomical variations in the calots triangle encountered during laparoscopic cholecystectomy are not uncommon. Misidentification and misperception of these structures are the major cause of vasculobiliary injuries. This study was conducted to estimate the prevalence of anatomical variations of the cystic artery, cystic duct (CD), and gall bladder. This is the first study in India to access the rate of intraoperative and postoperative complications in anatomical variants compared to normal individuals. Patients and methods: It was a prospective observational study on patients undergoing laparoscopic cholecystectomy in the department of General Surgery at the tertiary center of India. The calculated sample size was 298. Variations of the cystic artery, CD, and gall bladder along with intraoperative and postoperative complications were noted. The comparative analysis of intraoperative and postoperative complications and a subgroup analysis between anatomical variants and normal patients were performed. Results: The most common variations were found in cystic arteries (16.8%). CD anomalies were present in 11.4% of patients, and gall bladder anomalies were the least common of all (5.4%). Intraoperative and postoperative complications were compared between patients with anatomical variations and normal anatomy. Intraoperative complications in patients with anatomical variations were significantly higher. Bile leak (15.7% vs. 6.4%) (P=0.01), haemorrhage (16.8% vs. 1.9%) (P-value <0.001), conversion to open (3 vs. 0 patients) (P-value =0.03). Subgroup analysis revealed a strong association between intraoperative haemorrhage and bile leak with cystic artery and CD anomalies, respectively. Conclusion: Cystic artery anomalies are the most common variations. Patients with anatomical variations had significant intraoperative and postoperative complications compared to patients with normal anatomy.

Unusual Initial Presentation of Hepatocellular Carcinoma as a Clavicular Head Mass.

BACKGROUND: Hepatocellular carcinoma (HCC) is a common cancer worldwide. Extrahepatic spread is not unusual during HCC disease, but bone metastases at initial presentation are rare. CASE DESCRIPTION: We describe a case of HCC presenting with a clavicular head mass and spinal metastases with normal α-fetoprotein (AFP) level and hepatitis C virus infection without cirrhosis. After undergoing bone and liver biopsies, the patient started a 12-week course of sofosbuvir/velpatasvir and bevacizumab/atezolizumab for lifelong therapy with palliative intent. Since 2021, the patient has been receiving a combination of bevacizumab and atezolizumab every 21 days. On this regimen as of March 2023, his osseous metastases were stable and his liver lesions had not enlarged. CONCLUSIONS: This case demonstrates a very unusual HCC presentation, the importance of a thorough workup of bone metastasis, and the limited value of AFP for HCC screening, even in disseminated disease.

Novel SOX10 indel mutations drive schwannomas through impaired transactivation of myelination gene programs.

BACKGROUND: Schwannomas are common peripheral nerve sheath tumors that can cause severe morbidity given their stereotypic intracranial and paraspinal locations. Similar to many solid tumors, schwannomas and other nerve sheath tumors are primarily thought to arise due to aberrant hyperactivation of the RAS growth factor signaling pathway. Here, we sought to further define the molecular pathogenesis of schwannomas. METHODS: We performed comprehensive genomic profiling on a cohort of 96 human schwannomas, as well as DNA methylation profiling on a subset. Functional studies including RNA sequencing, chromatin immunoprecipitation-DNA sequencing, electrophoretic mobility shift assay, and luciferase reporter assays were performed in a fetal glial cell model following transduction with wildtype and tumor-derived mutant isoforms of SOX10. RESULTS: We identified that nearly one-third of sporadic schwannomas lack alterations in known nerve sheath tumor genes and instead harbor novel recurrent in-frame insertion/deletion mutations in SOX10, which encodes a transcription factor responsible for controlling Schwann cell differentiation and myelination. SOX10 indel mutations were highly enriched in schwannomas arising from nonvestibular cranial nerves (eg facial, trigeminal, vagus) and were absent from vestibular nerve schwannomas driven by NF2 mutation. Functional studies revealed these SOX10 indel mutations have retained DNA binding capacity but impaired transactivation of glial differentiation and myelination gene programs. CONCLUSIONS: We thus speculate that SOX10 indel mutations drive a unique subtype of schwannomas by impeding proper differentiation of immature Schwann cells.

A study on the clinical spectrum of Hepatitis C virus infection from a tertiary care center in Sub-Himalayan India-spontaneous clearance, a neglected phenomenon.

Hepatitis C virus (HCV) infection has varied clinical manifestations. Noninvasive tools can be useful to assess the severity of liver disease and the rate of spontaneous clearance. HCV infection was determined by antibody or RNA-based tests over a period of 18 months in 8030 samples from the Gastroenterology department. Noninvasive indicators (AST-to-platelet ratio index and fibrosis-4 index) were computed. HCV RNA load was compared with Child-Turcotte-Pugh score. Rate of spontaneous clearance was estimated. About 3.2% of patients were found to have HCV. Fatigue, anorexia, and nausea were the primary complaints followed by ascites and encephalopathy. Extrahepatic features such as autoimmune hepatitis and non-Hodgkin's lymphoma were rare. There was an absence of advanced liver cirrhosis (κ = 0.96) in the majority of cases. Spontaneous HCV resolution was seen in 10.37%.

Preventive hepatology: An ounce of prevention or pounds of cure to curb liver diseases.

Liver diseases are now the leading cause of both morbidity and mortality profile globally with rising trends due to unhealthy lifestyle. Most of the liver diseases are preventable. Scientific evidences have well supported and documented that almost 90 percent of all major liver diseases are either the manifestations of asymptomatic hepatitis virus infections or poor lifestyle choices leading to accumulation of fat in liver that could be detected even before they present themselves as chronic liver diseases. Understanding liver diseases as a preventable disease and practising necessary preventive measures will help in lowering the risks of various types of liver diseases as well as liver cancer.

A rare case of Rosai-Dorfman disease presenting as a pulmonary artery mass in a 33-year-old female with hypoxia.

Rosai-Dorfman disease (RDD) is a rare form of non-Langerhans histiocytosis. It is often idiopathic in etiology, but has been associated with viral, autoimmune, and malignant disease. Adequate diagnosis of RDD requires a combination of clinical symptoms, radiography, and histology. Most commonly, patients with RDD present with cervical lymphadenopathy. We describe a case of a young female who was initially thought to have a pulmonary embolism at the time of a COVID-19 infection but was noted to have a rare occurrence of RDD presenting as a pulmonary artery mass upon further evaluation of radiology and histology. Though RDD is frequently benign, extranodal involvement can progress to end organ damage and must be recognized appropriately.

Photonic-Plasmonic Coupling Enhanced Fluorescence Enabling Digital-Resolution Ultrasensitive Protein Detection.

Assays utilizing fluorophores are common throughout life science research and diagnostics, although detection limits are generally limited by weak emission intensity, thus requiring many labeled target molecules to combine their output to achieve higher signal-to-noise. We describe how the synergistic coupling of plasmonic and photonic modes can significantly boost the emission from fluorophores. By optimally matching the resonant modes of a plasmonic fluor (PF) nanoparticle and a photonic crystal (PC) with the absorption and emission spectrum of the fluorescent dye, a 52-fold improvement in signal intensity is observed, enabling individual PFs to be observed and digitally counted, where one PF tag represents one detected target molecule. The amplification can be attributed to the strong near-field enhancement due to the cavity-induced activation of the PF, PC band structure-mediated improvement in collection efficiency, and increased rate of spontaneous emission. The applicability of the method by dose-response characterization of a sandwich immunoassay for human interleukin-6, a biomarker used to assist diagnosis of cancer, inflammation, sepsis, and autoimmune disease is demonstrated. A limit of detection of 10 fg mL-1 and 100 fg mL-1 in buffer and human plasma respectively, is achieved, representing a capability nearly three orders of magnitude lower than standard immunoassays.