Uncovering the Role of Methylmercury on DNA Lesions at Cytotoxic Concentrations in Glutathione-Depleted Cells: Insights from Experimental and Computational Studies.

Organomercurials (RHg+), especially methylmercury (MeHg+) and ethylmercury (EtHg+), are considered to be more neurotoxic than the inorganic counterpart (Hg2+). They cause massive DNA damage in cells, especially in neurons, where cellular glutathione (GSH) levels are significantly low. However, the mechanism by which RHg+ exerts massive DNA damage at cytotoxic concentrations in brain cells remains obscure. In this study, we investigated the effect of RHg+ on the structural and electronic properties of nucleosides and its effects on DNA damage. The direct interaction of RHg+ with the nucleoside significantly weakens N-glycosidic bonds, decreases the C-H bond energy of sugar moieties, and increases the electrophilicity of the C8-center of purine bases. As a consequence, RHg+-conjugated DNA molecules are extremely labile and highly sensitive to any nucleophiles/radicals present in GSH-depleted cells and, thus, undergo enhanced oxidative and unusual alkylative DNA damage. We also report a functional model of organomercurial lyase, which showed excellent cytoprotective effect against RHg+-induced cytotoxicity; this reverses the activity of glutathione reductase inhibited by MeHgCl and ceases oxidative and alkylating DNA damage. This intriguing finding provides new mechanistic insight into the mode of action of organomercurials in GSH-depleted cells and their adverse effects on individuals with neurodegenerative disorders associated with oxidative stress.

Regulation of Tyrosinase Enzyme Activity by Glutathione Peroxidase Mimics.

Hydrogen peroxide plays a crucial role in the melanogenesis process by regulating the activity of the key melanin-forming enzyme tyrosinase, responsible for the browning of fruits, vegetables, and seafood. Therefore, a molecule with dual activities, both efficient tyrosinase inhibition and strong hydrogen peroxide degrading ability, may act as a promising antibrowning agent. Herein, we report highly efficient selone-based mushroom tyrosinase inhibitors 2 and 3 with remarkable glutathione peroxidase (GPx) enzyme-like activity. The presence of benzimidazole moiety enhances the tyrosinase inhibition efficiency of selone 2 (IC50 = 0.4 µM) by almost 600 times higher than imidazole-based selone 1 (IC50 = 238 µM). Interestingly, the addition of another aromatic ring to the benzimidazole moiety has led to the development of an efficient lipid-soluble tyrosinase inhibitor 3 (IC50 = 2.4 µM). The selenium center and the -NH group of 2 and 3 are extremely crucial to exhibit high GPx-like activity and tyrosinase inhibition potency. The hydrophobic moiety of the inhibitors (2 and 3) further assists them in tightly binding at the active site of the enzyme and facilitates the C═Se group to strongly coordinate with the copper ions. Inhibitor 2 exhibited excellent antibrowning and polyphenol oxidase inhibition properties in banana and apple juice extracts.

Open Versus Laparoscopic Ventral Hernia Repair: A Randomized Clinical Trial.

Introduction With the advancement in technology as well as surgical techniques, laparoscopic ventral hernia repair (LVHR) is more commonly being performed as compared to open repair in various centres throughout the world. Our study aimed to compare the short-term operative outcomes between LVHR and open repair. Materials and methods Sixty patients diagnosed with noncomplicated ventral hernias were included in this prospective study and were randomly divided into the laparoscopic group and the open group. The two groups were compared to evaluate operative time, postoperative pain, length of hospital stay and time taken to return to normal activity. A p-value of less than 0.05 was considered to be statistically significant. Results Mean operative time was longer in LVHR (116 min) as compared to open repair (67 min)(p<0.01). Patients experienced more pain on the first and seventh postoperative days in the open group (p<0.01) and they also had a longer duration of hospital stay as compared to the laparoscopic group (6.23 ± 0.35 vs 2.17 ± 1.12 days, p = 0.02). Patients in the laparoscopic group returned to normal activity faster as compared to the open group (1.47 ± 0.11 vs 2.87 ± 0.34, p<0.01). Conclusion LVHR carries a significant advantage over open hernia repair, especially in terms of reduced postoperative pain, duration of hospital stay, and early resumption of normal activity.

Open Lichtenstein Hernioplasty Versus Laparoscopic Transabdominal Preperitoneal Mesh Repair: The Pain Factor.

Introduction One of the most commonly performed surgery by a general surgeon is inguinal hernia repair. There have been numerous open surgical techniques and two laparoscopic techniques described in the literature for the treatment of inguinal hernias. The treatment outcome of all these surgeries remains the same which is reducing the hernia and preventing recurrence. Our aim was to compare laparoscopic versus open inguinal hernia repair with emphasis on postoperative pain. Methods One hundred and twenty patients with unilateral primary inguinal hernias were randomly divided into two groups. Each group included 60 patients. Group one was treated by open Lichtenstein repair, while the second group was treated by laparoscopic transabdominal preperitoneal (TAPP) mesh repair. The two groups were compared to assess the duration of surgery, postoperative pain, duration of hospital stay, return to normal activity, and work. Results Laparoscopic TAPP repair was found to have a longer operative time as compared to Liechtenstein open repair. In terms of other parameters such as postoperative pain duration of hospital stay, return to normal activity, and work the laparoscopic group was superior. After a one-year follow-up, none of the patients had any chronic pain or evidence of hernia recurrence. Conclusion Laparoscopic TAPP has a clear advantage over the conventional Liechtenstein open surgery especially in terms of reduced early post postoperative pain and return to normal activity.

Hg-C bond protonolysis by a functional model of bacterial enzyme organomercurial lyase MerB.

Herein, we report a novel synthetic compound 1, having a highly nucleophilic selenolate (Se-) moiety and a thiol (-SH) functional group, which showed efficient Hg-C bond protonolysis of various R-Hg-X molecules including neurotoxic methylmercury and thimerosal, via direct -SH proton transfer to the highly activated C-atom of a departed R group with low activation energy barrier at room temperature (21 °C), in the absence of any external proton source and, thus, acts as a functional model of MerB.

Intravascular Thrombolysis Followed by Stenting as Management of Retrohepatic Inferior Vena Caval Thrombosis due to a Twist in the Inferior Vena Cava after Deceased Donor Liver Transplant.

Inferior vena cava (IVC) occlusion due to acute thrombosis is a rare but important vascular complication after deceased donor liver transplantation (DDLT) that has been reported to occur up to 2% of recipients in a posttransplant period. This may be caused by direct instrumentation of the IVC stenosis at the anastomotic site, haematoma, and rarely by a twist in the retrohepatic IVC. The location of the thrombus, the timing after the surgery, and associated hemodynamic disturbances define the outcome of the patient. Without prompt diagnosis and timely intervention, the outcome after IVC thrombosis is usually dismal. Herein, we report a rare case of near-complete occlusion of the IVC secondary to intracaval thrombosis after DDLT associated with twisting of the IVC at the suprahepatic anastomosis which was successfully managed by intravascular thrombolysis and stenting.

Role of Hydrogen Bonding by Thiones in Protecting Biomolecules from Copper(I)-Mediated Oxidative Damage.

The sulfur-containing antioxidant molecule ergothioneine with an ability to protect metalloenzymes from reactive oxygen species (ROS) has attracted significant interest in both chemistry and biology. Herein, we demonstrated the importance of hydrogen bonding in S-oxygenation reactions between various thiones and H2O2 and its significance in protecting the metal ion from H2O2-mediated oxidation. Among all imidazole- and benzimidazole-based thiones (1-10), ImMeSH (2) showed the highest reactivity toward H2O2-almost 10 and 75 times more reactive than N, N'-disubstituted ImMeSMe (5) and BzMeSMe (10), respectively. Moreover, metal-bound ImMeSH (2) of [TpmCu(2)]+ (13) was found to be 51 and 1571 times more reactive toward H2O2 than the metal-bound ImMeSMe (5) of [TpmCu(5)]+ (16), and BzMeSMe (10) of [TpmCu(10)]+ (21), respectively. The electron-donating N-Me substituent and the free N-H group at the imidazole ring played a very crucial role in the high reactivity of ImMeSH toward H2O2. The initial adduct formation between ImMeSH and H2O2 (ImMeSH·H2O2) was highly facilitated (-23.28 kcal mol-1) due to the presence of a free N-H group, which leads to its faster oxygenation than N, N'-disubstituted ImMeSMe (5) or BzMeSMe (10). As a result, ImMeSH (2) showed a promising effect in protecting the metal ion from H2O2-mediated oxidation. It protected biomolecules from Cu(I)-mediated oxidative damage of through coordination to the Cu(I) center of [TpmCu(CH3CN)]+ (11), whereas metal-bound ImMeSMe or BzMeSMe failed to protect biomolecules under identical reaction conditions.

Simultaneous voltammetric immunodetection of alpha-fetoprotein and glypican-3 using a glassy carbon electrode modified with magnetite-conjugated dendrimers.

The authors describe an electrochemical immunoassay for simultaneous determination of alpha-fetoprotein (AFP) and glypican-3 (GPC-3) which are important biomarkers for early detection of hepatocellular carcinoma (HCC). Magnetite (Fe3O4) nanoparticles (NPs) were decorated with hyperbranched amino functionalized dendrimers. The modified NPs were coupled to the antibodies against AFP and GPC-3. The electrochemical behaviour of the Fe3O4 NPs and dendrimer-modified NPs were studied. A glassy carbon electrode was then modified with the NP-conjugated antibodies and biomolecular interactions were studied by using cyclic voltammetry and electrochemical impedance spectroscopy. Dual differential pulse voltammetric sensing was performed by utilizing the redox probes; Prussian blue for AFP and toluidine blue for GPC-3. The biomarkers can be detected best at voltages of 0.25 mV and - 0.54 mV (vs Ag/AgCl) for AFP and GPC-3, respectively. The low working potentials makes the method more selective over other electroactive species present in real human serum samples. Response is linear in 0.02 to 10 ng mL-1 concentration ranges of both AFP and GPC-3; and the respective detection limits are 50 and 70 pg mL-1. The method was validated by analysing spiked human serum samples. In our perception, the method is of great clinical significance as combination of GPC-3 and AFP increases the sensitivity of detection of HCC. Graphical abstract Schematic presentation of polyamidoamine (PAMAM) dendrimers modified magnetite (Fe3O4) nanoparticles as electrochemical sensing platform using redox dyes Prussian blue and toluidine blue for simultaneous detection of alpha-fetoprotein (AFP) and glypican-3 (GPC-3), respectively by differential pulse voltammetry.

Copper-Driven Deselenization: A Strategy for Selective Conversion of Copper Ion to Nanozyme and Its Implication for Copper-Related Disorders.

Synthetic organic molecules, which can selectively convert excess intracellular copper (Cu) ions to nanozymes with an ability to protect cells from oxidative stress, are highly significant in developing therapeutic agents against Cu-related disorder like Wilson's disease. Here, we report 1,3-bis(2-hydroxyethyl)-1 H-benzoimidazole-2-selenone (1), which shows a remarkable ability to remove Cu ion from glutathione, a major cytosolic Cu-binding ligand, and thereafter converts it into copper selenide (CuSe) nanozyme that exhibits remarkable glutathione peroxidase-like activity, at cellular level of H2O2 concentration, with excellent cytoprotective effect against oxidative stress in hepatocyte. Cu-driven deselenization of 1, under physiologically relevant conditions, occurred in two steps. The activation of C═Se bond by metal ion is the crucial first step, followed by cleavage of the metal-activated C═Se bond, initiated by the OH group of N-(CH2)2OH substituent through neighboring group participation (deselenization step), resulted in the controlled synthesis of various types of Cu2-xSe nanocrystals (NCs) (nanodisks, nanocubes, and nanosheets) and tetragonal Cu3Se2 NCs, depending upon the oxidation state of the Cu ion used to activate the C═Se bond. Deselenization of 1 is highly metal-selective. Except Cu, other essential metal ions, including Mn2+, Fe2+, Co2+, Ni2+, or Zn2+, failed to produce metal selenide under identical reaction conditions. Moreover, no significant change in the expression level of Cu-metabolism-related genes, including metallothioneines MT1A, is observed in liver cells co-treated with Cu and 1, as opposed to the large increase in the concentrations of these genes observed in cells treated with Cu alone, suggesting the participation of 1 in Cu homeostasis in hepatocyte.

Cytoprotective effects of imidazole-based [S1] and [S2]-donor ligands against mercury toxicity: a bioinorganic approach.

Here we report the coordination behaviour of an imidazole-based [S1]-donor ligand, 1,3-dimethyl-imidazole-2(3H)-thione (L1), and [S2]-donor ligand, 3,3'-methylenebis(1-methyl-imidazole-2(3H)-thione) (L2) or 4,4'-(3,3'-methylenebis-(2-thioxo-2,3-dihydro-imidazole-3,1-diyl))dibutanoic acid (L3), with HgX2 (X = Cl, Br or I) in solution and the solid state. NMR, UV-Vis spectroscopic, and single crystal X-ray studies demonstrated that L1 or L2 coordinated rapidly and reversibly to the mercury center of HgX2 through the thione moiety. Treatment of L2 with HgCl2 or HgBr2 afforded 16-membered metallacycle k1-(L2)2Hg2Cl4 or k1-(L2)2Hg2Br4 where two Cl or Br atoms are located inside the ring. In contrast, treatment of L2 with HgI2 afforded a chain-like structure of k1-[L2Hgl2]n, possibly due to the large size of the iodine atom. Interestingly, [S1] and [S2]-donor ligands (L1, L2, and L3) showed an excellent efficacy to protect liver cells against HgCl2 induced toxicity and the strength of their efficacy is in the order of L3 > L2 > L1. 30% decrease of ROS production was observed when liver cells were co-treated with HgCl2 and L1 in comparison to those cells treated with HgCl2 only. In contrast, 45% and 60% decrease of ROS production was observed in the case of cells co-treated with HgCl2 and thiones L2 and L3, respectively, indicating that [S2]-donor ligands L2 and L3 have better cytoprotective effects against oxidative stress induced by HgCl2 than [S1]-donor ligand L1. Water-soluble ligand L3 with N-(CH2)3CO2H substituents showed a better cytoprotective effect against HgCl2 toxicity than L2 in liver cells.

Metal-free C(sp2)-H functionalization of azoles: K2CO3/I2-mediated oxidation, imination, and amination.

The direct C2-H oxidation and imination of a wide variety of azoles was achieved by using a commercially available simple K2CO3/I2 reagent combination. The iodinated azole adduct, produced via the in situ generation of N-heterocyclic carbene, is the key intermediate for C2-H oxidation, imination, and amination of azoles. Significantly, these reactions proceed under mild conditions with high to excellent yields, are scalable to large quantity and exhibit a broad substrate scope. Interestingly, this direct C2-H imination method allowed us to access various pharmacologically active N6-alkyl or N6-aryl substituted benzimidazoquinazolinone scaffolds through intramolecular C-H imination in a sequential one-pot reaction.

Protection of Endogenous Thiols against Methylmercury with Benzimidazole-Based Thione by Unusual Ligand-Exchange Reactions.

Organomercurials, such as methylmercury (MeHg+ ), are among the most toxic materials to humans. Apart from inhibiting proteins, MeHg+ exerts its cytotoxicity through strong binding with endogenous thiols cysteine (CysH) and glutathione (GSH) to form MeHgCys and MeHgSG complexes. Herein, it is reported that the N,N-disubstituted benzimidazole-based thione 1 containing a N-CH2 CH2 OH substituent converts MeHgCys and MeHgSG complexes to less toxic water-soluble HgS nanoparticles (NPs) and releases the corresponding free thiols CysH and GSH from MeHgCys and MeHgSG, respectively, in solution by unusual ligand-exchange reactions in phosphate buffer at 37 °C. However, the corresponding N-substituted benzimidazole-based thione 7 and N,N-disubstituted imidazole-based thione 3, in spite of containing a N-CH2 CH2 OH substituent, failed to convert MeHgX (X=Cys, and SG) to HgS NPs under identical reaction conditions, which suggests that not only the N-CH2 CH2 OH moiety but the benzimidazole ring and N,N-disubstitution in 1, which leads to the generation of a partial positive charge at the C2 atom of the benzimidazole ring in 1:1 MeHg-conjugated complex of 1, are crucial to convert MeHgX to HgS NPs under physiologically relevant conditions.

A Special Extract of Bacopa monnieri (CDRI-08) Restores Learning and Memory by Upregulating Expression of the NMDA Receptor Subunit GluN2B in the Brain of Scopolamine-Induced Amnesic Mice.

In the present communication, we have investigated effects of the CDRI-08, a well characterized extract of Bacopa monnieri, on expression of the GluN2B subunit of NMDAR in various brain regions of the scopolamine-induced amnesic mice. Our behavioral data reveal that scopolamine-treated amnesic mice exhibit significant decline in the spatial memory compared to the normal control mice. Our RT-PCR and immunoblotting data revealed that the scopolamine treatment resulted in a significant downregulation of the NMDAR GluN2B subunit expression in prefrontal cortex and hippocampus. Our enzyme assay data revealed that scopolamine caused a significant increase in the acetylcholinesterase activity in both the brain regions. Further, oral administration of the CDRI-08 to scopolamine-treated amnesic mice restored the spatial memory which was found to be associated with significant upregulation of the GluN2B subunit expression and decline in the acetylcholinesterase activity in prefrontal cortex as well as hippocampus towards their levels in the normal control mice. Our study provides the evidence for the mechanism underlying role of the Bacopa monnieri extract (CDRI-08) in restoring spatial memory in amnesic mice, which may have therapeutic implications.

Development- and age-related alterations in the expression of AMPA receptor subunit GluR2 and its trafficking proteins in the hippocampus of male mouse brain.

AMPA type glutamate receptor (AMPAR) on the post synaptic membrane plays important role in the process of synaptic plasticity involving various scaffolding and trafficking proteins. However, their alterations during development- and aging are not well understood. Here, we report that the expression of AMPAR-GluR2 subunit is gradually up regulated in the hippocampus from 0 day to adult (20 week) and down regulated thereafter in 70 week old male mice. This pattern of GluR2 during development (0-, 7- and 15 day), maturation (45 day) and adult age resembles with similar expression pattern of the scaffolding protein PSD95. Expression pattern of Stargazin (TARPγ-2) largely follows almost similar pattern up to adult age but is up regulated in old age. Pattern of PICK1 expression, however, is opposite to our GluR2 data till adult age but its expression is significantly down regulated in old age. Our data on alterations in the expression of GluR2 in the hippocampus during development and aging indicates a high- and low positive correlations with PSD95 and Stargazin, respectively whereas negative correlation with PICK1 except in old age where expression of Stargazin is higher and that of PICK1 is lower. Our findings suggest that increasing expression pattern of GluR2 during developmental periods and at adult age may be associated with achieving cognitive abilities whereas its low expression in old age may be linked with cognitive decline and proteins like PSD95, Stargazin and PICK1 might be differentially associated with development- and age-dependent alterations in AMPAR-dependent synaptic plasticity and hence learning and memory.

Vascular leiomyoma of foot.

Vascular leiomyomas of the foot are relatively rare benign soft tissue tumours which arise from the tunica media and present as painful or painless solitary subcutaneous nodules. We are reporting a rare case of vascular leiomyoma with a dystrophic calcification and a myxoid change.

Liver transplantatation- an overview.

Liver transplantation is a therapeutic option of choice for acute and chronic end-stage liver disease. Indications, contraindications, and surgical procedures for the liver transplantation have become well established. In most part of the world, the main source of liver for transplantation remains the donation after brain death (DBD), but in view of increasing death on the waiting list due to shortage of brain dead organs other options such as split liver transplantation, living donor liver transplantation (LDLT), and donation after cardiac death (DCD) have been used. In the pretransplantation era, liver failure was nearly universally fatal, with mortality from fulminant hepatic failure of 80-90 %, and 1-year mortality in decompensated cirrhosis of more than 50 %. In contrast, liver transplantation patient survival is presently more than 85 % at 1 year and more than 70 % at 5 years, emphasizing the clinical benefit of liver transplantation for either acute or chronic liver failure.

Augmented macrophage differentiation and polarization of tumor-associated macrophages towards M1 subtype in listeria-administered tumor-bearing host.

This study investigates the effect of Listeria administration on differentiation of macrophages from precursor bone marrow cells and functional status of tumor-associated macrophages (TAM). Listeria administration not only resulted in an augmented infiltration of tumor by F4/80 macrophages but also repolarized the functional status of TAM displaying features of some M1 macrophage subtype with upregulated phagocytosis and tumoricidal activity accompanied by altered expression of monocarboxylate transporter-1, toll-like receptor-2, surface markers: CD11c, interleukin-2 receptor, CD62L, and secreted molecules: nitric oxide, interleukin (IL)-1, IL-6, tumor necrosis factor-α, and vascular endothelial growth factor. Declined tumor cell survival and modulated repertoire of cytokines: interferon-γ, IL-6, IL-10, and transforming growth factor-ß in tumor microenvironment indicated their role in polarization of TAM towards proinflammatory state. Bone marrow cell of Listeria-administered tumor-bearing mice showed augmented survival, declined expression of p53 upregulated modulator of apoptosis with an upregulated differentiation into activation responsive bone marrow-derived macrophages along with altered expression of macrophage-colony stimulating factor, macrophage-colony stimulating factor receptor, and granulocyte macrophage-colony stimulating factor receptor. These findings indicate that Listeria infection is associated with an augmented differentiation of macrophages accompanied by tumoricidal activation of TAM.

Surgery in a patient with liver disease.

Surgery is often needed in patients with concurrent liver disease. The multiple physiological roles of the liver places these patients at an increased risk of morbidity and mortality. Diseases necessitating surgery like gallstones and hernia are more common in patients with cirrhosis. Assessment of severity of liver dysfunction before surgery is important and the risk benefit of the procedure needs to be carefully assessed. The disease severity may vary from mild transaminase rise to decompensated cirrhosis. Surgery should be avoided if possible in the emergency setting, in the setting of acute and alcoholic hepatitis, in a patient of cirrhosis who is child class C or has a MELD score more than 15 or any patient with significant extrahepatic organ dysfunction. In this subset of patients, all possible means to manage these patients conservatively should be attempted. Modified Child-Pugh scores and model for end-stage liver disease (MELD) scores can predict mortality after surgery fairly reliably including nonhepatic abdominal surgery. Pre-operative optimization would include control of ascites, correction of electrolyte imbalance, improving renal dysfunction, cardiorespiratory assessment, and correction of coagulation. Tests of global hemostasis like thromboelastography and thrombin generation time may be more predictive of the risk of bleeding compared with the conventional tests of coagulation in patients with cirrhosis. Correction of international normalized ratio with fresh frozen plasma does not necessarily mean reduction of bleeding risk and may increase the risk of volume overload and lung injury. International normalized ratio liver may better reflect the coagulation status. Recombinant factor VIIa in patients with cirrhosis needing surgery needs further study. Intra-operatively, safe anesthetic agents like isoflurane and propofol with avoidance of hypotension are advised. In general, nonsteroidal anti-inflammatory drug (NSAIDs) and benzodiazepines should not be used. Intra-abdominal surgery in a patient with cirrhosis becomes more challenging in the presence of ascites, portal hypertension, and hepatomegaly. Uncontrolled hemorrhage due to coagulopathy and portal hypertension, sepsis, renal dysfunction, and worsening of liver failure contribute to the morbidity and mortality in these patients. Steps to reduce ascitic leaks and infections need to be taken. Any patient with cirrhosis undergoing major surgery should be referred to a specialist center with experience in managing liver disease.

Jejunal atresia associated with idiopathic ileal perforation.

Jejunoileal atresia is one of the common causes of neonatal intestinal obstruction. Intestinal perforation with meconium peritonitis in the neonatal period, which carries a high mortality rate, is also common. The association of jejunal atresia with idiopathic ileal perforation is very rare.