Pseudocholinesterase Activity Research Articles

Study of Organophosphorus Poisoning at a Tertiary Care Teaching Hospital

Introduction: Organophosphate (OP) insecticides inhibit both cholinesterase and pseudo-cholinesterase activities. The inhibition of acetylcholinesterase causes accumulation of acetylcholine at synapses, and overstimulation of neurotransmission occurs as a result of this accumulation. The mortality rate of OP poisoning is high. Early diagnosis and appropriate treatment is often life saving. Treatment of OP poisoning consists of intravenous atropine and oximes. The clinical course of OP poisoning may be quite severe and may need intensive care management. Methods: A retrospective study was performed on the patients with OP poisoning. Fifty patients were included. Diagnosis was performed from the history taken either from the patient or from the patient's relatives about the agent involved in the exposure. Diagnosis could was confirmed with serum and red blood cell anticholinesterase levels. Intravenous atropine and pralidoxime was administered as soon as possible. Other measures for the treatment were gastric lavage and administration of activated charcoal via nasogastric tube, and cleansing the patient's body with soap and water. The patients were intubated and mechanically ventilated if the patients had respiratory failure, a depressed level of consciousness, which causes an inability to protect the airway, and hemodynamic instability. Mechanical ventilation was performed as synchronized intermittent mandatory ventilation + pressure support mode, either as volume or pressure control. Positive end expiratory pressure was titrated to keep SaO2 above 94% with 40% FIO2. Weaning was performed using either T-tube trials or pressure support weaning. The chi-square test was used for statistical analysis. Data are presented as mean ± standard deviation. Results: There were 26 female and 24 male patients. Thirty-five were suicide attempts and 15 were accidental exposure. The gastrointestinal route was the main route in 44 patients. The most frequent signs were meiosis, change in mental status, hypersalivation and fasciculations. Ten patients (20.0%) required mechanical ventilation. Complications were observed in 35 patients. These complications were respiratory failure (14 patients), aspiration pneumonia (10 patients), urinary system infection (6 patients), convulsion (4 patients) and septic shock (1 patient). The duration of the intensive care stay was 5.2 ± 3.0 days. Discussion: Ingestion of OP compounds for suicidal purposes is a major problem, especially in developing countries. Thirty-five of our patients used the OP insecticide for suicide. The average respiratory rate of these patients increased from 22 to 38 breaths/min, which is an important sign of respiratory distress. The nurse to patient ratio was increased after these events. Early recognition of respiratory failure resulting in intubation and mechanical ventilation is a life-saving intervention for patients with OP poisoning. Respiratory failure is the most troublesome complication, which was observed in 35 patients. Patients with OP poisoning may have respiratory failure for many reasons, including aspiration of the gastric content, excessive secretions, pneumonia and septicemia complicating acute respiratory distress syndrome. Conclusions: OP insecticide poisoning is a serious condition that needs rapid diagnosis and treatment. Since respiratory failure is the major reason for mortality, careful monitoring, appropriate management and early recognition of this complication may decrease the mortality rate among these patients.

Detection the severity of organophosphate intoxication using sensitive serum biomarkers S100B and amyloid β (Aβ) in Egyptian subjects

Organophosphate (OP) is a compound considered the main leading cause of morbidity and mortality from poisoning worldwide. Serum pseudocholinesterase was evaluated as a diagnostic indicator; it cannot be used to monitor therapy or severity of the intoxication. The rationale of the current study was to evaluate sensitivity, specificity, and cut-off values of serum S100B and amyloid β for neurological affection severity. This study was carried out on sixty OP-impaired patients; in addition, 20 normal controls were included. Serum liver and kidney function tests, malondialdehyde, pseudocholinesterase, and the levels of S100B and amyloid β (Aβ) were determined. Data showed that Pearson’s analysis indicated that the serum level of S100B was positively correlated with Aβ. On the contrary, the activity of pseudocholinesterase was negatively correlated with both of S100B and Aβ. Serum ALT, AST, creatinine, urea, acetylcholine, and MDA levels were elevated while pseudocholinesterase activity was reduced in moderate and severe OP intoxication versus control. A drastic elevation (p<0.001) in the levels of S100B and Aβ was performed in the patient group suffering from OP intoxication versus the normal group. The diagnostic statistical validation of targeted parameters in distinguishing between moderate OP intoxication and control clarifies that S100B displayed the best AUC (0.997) followed by Aβ (AUC=0.992), while the diagnostic veracity of S100B and Aβ in setting apart severe OP-intoxicated and normal subjects stated the symmetric efficacy of potential markers. It was concluded that the significant changes in the levels of S100B and Aβ were directly proportional to the degree of severity of OP intoxication.

Investigation of the efficacy of diosmin against organ damage caused by bendiocarb in male Wistar albino rats.

Bendiocarb is a carbamate insecticide, which is used more in indoor areas, especially against scorpions, spiders, flies, mosquitoes and cockroaches. Diosmin is an antioxidant flavonoid found mostly in citrus fruits. In this study, the efficacy of diosmin against the adverse effects of bendiocarb was investigated in rats. For this purpose, 60, 2-3month-old male Wistar albino rats, weighing 150-200g, were used. The animals were assigned to six groups, one of which was maintained for control purposes and five of which were trial groups. The control rats received only corn oil, which was used as a vehicle for diosmin administration in the trial groups. Groups 2, 3, 4, 5 and 6 were administered with 10mg/kg.bw bendiocarb, 10mg/kg.bw diosmin, 20mg/kg.bw diosmin, 2mg/kg.bw bendiocarb plus 10mg/kg.bw diosmin, and 2mg/kg.bw bendiocarb plus 20mg/kg.bw diosmin, respectively, using an oral catheter, for 28days. At the end of the study period, blood and organ (liver, kidneys, brain, testes, heart and lungs) samples were collected. Body weight and organ weights were determined. Compared to the control group, in the group given bendiocarb alone, firstly, body weight and liver, lung and testicular weights decreased. Secondly, tissue/plasma malondialdehyde (MDA) and nitric oxide (NO) levels increased, and glutathione (GSH) levels and superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) (except for lung tissue), glutathione reductase (GR), and glucose-6-phosphate dehydrogenase (G6PD) activities decreased in alltissues and erythrocytes. Thirdly, catalase (CAT) activity decreased in erythrocytes and the kidney, brain, heart and lung tissues and increased in the liver and testes. Fourthly, while GST activity decreased in the kidneys, testes, lung and erythrocytes, an increase was observed in the liver and heart tissues. Fifthly, while serum triglyceride levels and lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and pseudo-cholinesterase (PchE) activities decreased, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities and blood urea nitrogen (BUN), creatinine and uric acid levels increased. Lastly, liver caspase 3, caspase 9 and p53 expression levels significantly increased. When compared to the control group, the groups treated with diosmin alone showed no significant difference for the parameters investigated. On the other hand, it was observed that the values of the groups treated with a combination of bendiocarb and diosmin were closer to the values of the control group. In conclusion, while exposure to bendiocarb at a dose of 2mg/kg.bw for 28days caused oxidative stress/organ damage, diosmin administration at doses of 10 and 20mg/kg.bw reduced this damage. This demonstrated that diosmin has pharmaceutical benefits, when used for supportive treatment as well as radical treatment, against the potential adverse effects of bendiocarb.

A Comparative Study of the Triglycerides/HDL Ratio and Pseudocholinesterase Levels in Patients with Bladder Cancer.

Background: Lipid alterations may serve as potential tumour biomarkers. The ratio of triglycerides to HDL cholesterol (TG/HDL ratio) is associated with various cancers. Pseudocholinesterase (PChE) activity, involved in TG hydrolysis, plays an important role in the metabolism of lipoprotein. There is scarce data assessing the reliability of both the TG/HDL ratio and PChE levels in correctly classifying patients suffering from bladder cancer. Methods: Three hundred and ninety-six patients undergoing cystoscopy or transurethral resection of the bladder (TURB), broken into two major groups, i.e., patients with histologically confirmed, non-metastatic bladder cancer (n = 208) and without bladder cancer (no bladder cancer, n = 188), formed the study population. The last group was split into two subgroups consisting of a cohort of patients never suffering from bladder cancer but with other bladder diseases (no CaBD, n = 100) and another cohort formed by patients characterised by eradicated bladder cancer after TURB with no recurrence during a three-month follow-up (previous bladder cancer, n = 88). Pieces of information by both metabolic derangement (the presence of type 2 diabetes mellitus), hypertension and lipid profile were retrieved from patient records upon entry to the study. Sensitivity, specificity, areas under the ROC (AUROC) of the TG/HDL ratio, and PChE levels were used in diagnostic decision making. Results: The TG/HDL ratio as well as PChE concentrations of bladder cancer patients were significantly different when compared to those with previous bladder cancer and the no CaBD patients (p = 0.023 and 0.0004, respectively). There was an independent role of both the TG/HDL ratio and PChE levels in predicting the presence of bladder cancer (OR: 1.22 and 0.99, respectively), but the reliability of the TG/HDL ratio (AUROC: 0.587) was superior to that of PChE levels (AUROC: 0.374). The AUROC of a new parameter resulting from the combination of the TG/HDL ratio with PChE levels showed a further increment in the discriminant power of the bladder cancer presence (0.6298), interestingly with a negative predictive value (89%) according to the Bayesian approach. The cut-off of the TG/HDL ratio, the main marker of the present study that better distinguishes bladder cancer from no bladder cancer patients, was 2.147. Discussion and Conclusions: The reliability of the TG/HDL ratio is based on the fact that this parameter likely mirrors the insulin resistance (IR) underlying bladder cancer patients. Furthermore, PChE levels evidence both IR and the associated non-alcoholic fatty liver disease. The TG/HDL ratio and PChE levels as well as their combined use could help physicians to assess/confirm the presence of this very common cancer, where early detection is important to ensure the best therapeutical approach.

“A CLINICAL STUDY ON PSEUDOCHOLINESTERASE LEVELS AS A PROGNOSTIC MARKER IN ORGANOPHOSPHORUS COMPOUND POISONING IN A TERTIARY CARE HOSPITAL."

Background: One of the most common poisonings in India is organophosphorus compound poisoning. The rise in agricultural pesticide use has paralleled the rise in the use of these products for intentional self-harm. In addition to a clinical diagnosis, this requires a set biochemical parameter. The research aims to provide a useful prognostic marker in treating organophosphorus compound poisoning. Aim: Ÿ To study the pseudocholinesterase levels as a prognostic marker in the outcome of organophosphorus compound poisoning Ÿ To predict the prognosis and mortality based on pseudocholinesterase activity Materials And Methods: A Hospital-based observational Prospective study was conducted in the Department of Medicine, Santhiram medical college, and the general hospital for six months. Atotal 50 number of patients with a history of consumption of organophosphorus compounds were admitted, investigated and followed up. Results: In the study, it was noted that 70% were suicidal, and 30% were of accidental poisoning. Organophosphate compound poisoning is more common in males. The male and female ratio was 2.57:1. The maximum number of cases in our study, about 86% of cases were below 40 years. 100% of cases in the present study showed low pseudocholinesterase activity on admission. Conclusion: Determining pseudocholinesterase activity is a reliable diagnostic test in the early stages of organophosphorus poisoning. The study also demonstrates that a higher rise in enzyme activity is directly proportional to a better prognosis.

Acetylcholinesterase Inhibition of Marine Fish (Rastrelliger kanagurta) by Organophosphorus Pesticides as Biomarker of Neurotoxicants

This paper evaluated the inhibitory effects of various phosphorothioates (Ethyl parathion and Chlorpyriphos) and phosphates (DDVP, Monocrotophos and Phosphamidon) on acetylcholinesterase (AChE) of marine Mackerel fish (Rastrelliger kanagurta) from the Goa coast. The characteristics of the AChE enzymes isolated from different tissues of the fishes for their affinity towards the substrate were determined by the Michaelis Menten constants. The pseudocholinesterase activity was also measured in the muscle tissues in terms of Butyryl-cholinesterase (BChE) activity of the fish. The AChE activity was found to be predominant in the Brain, gills, liver and muscle tissues. However, no significant BChE activity was observed in the muscle tissue. Among the five organophosphorus pesticides, DDVP was found to be most toxic with least I50 values (0.99±0.04nM) followed by Chlorpyriphos (I50, 24.59±2.86 nM), Ethyl Parathion (I50, 183.21±11.68 nM), Monocrotophos (I50, 13536.93±1292.94 nM) and Phosphamidon (I50, 21433.1±2651.96 nM) in the decreasing order. The I50 values of all other pesticides decreased considerably with respect to DDVP. The relative neurotoxicity of the pesticides decreased by an order of magnitude in the case of Chlorpyriphos followed by Ethyl Parathion by an order of magnitude whereas in the case of Monocrotophos and Phosphamidon the toxicity decreased significantly by an order of magnitude. The variation in the muscle AChE inhibition by the organophosphorus pesticides can be attributed to the sensitivity of the enzyme for each of the pesticides as observed by the bimolecular inhibition constants (KII). The muscle AChE inhibition of Rastrelliger kanagurta can be used as biomarker for bio- monitoring of neurotoxic contaminants in the marine environment.

Clinical utility of validated gas chromatography–ion trap mass spectrometry in patients with anticholinesterase pesticides poisoning

Intentional or unintentional intake of anticholinesterase pesticides became common due to their extensive use in agricultural and domestic purposes, resulting in numerous poisoning cases. A simple, accurate, and sensitive gas chromatography-ion trap mass spectrometry-based method for the quantification of 12 anticholinesterase pesticides (monocrotophos, dimethoate, dichlorvos, azinphos-methyl, carbofuran, chlorpyrifos, dialifos, diazinon, malathion, parathion, methidathion, and terbufos) in serum was developed, and its utility in patients with alleged pesticides poisoning was assessed. The quantification was performed using liquid-liquid extraction by toluene/chloroform (4:1,v/v) with 500 μL of serum. On column limit of detection and limit of quantification were less than 50.00 μg/L. The recovery ranged from 97.54 to 103.23%. The calibration curves were linear (R2 > 0.9937). Accuracy was found to be between – 7.1 and 7.2%. Intra-day and inter-day reproducibility was less than 17% for the spiked quality control serum samples. The level of pesticide in serum quantified by the validated method correlated with clinical signs and symptoms, pseudo-cholinesterase activity, total atropine dose, length of hospital stay, and clinical outcome in 15 patients with alleged pesticide poisoning. The validated method may be used for monitoring and prognosis in patients with pesticide poisoning and diagnosis of poisoning in forensic toxicology.

Role of Plasma Cholinesterase level in Assessment of Severity and Outcome in Organophosphorus Poisoning

Introduction: Organophosphorus poisoning is associated with high rate of mortality if not diagnosed and treated in time. Therefore aim of present study is to evaluate the significance of cholinesterase activity in assessing severity and to predict the outcome of Organophosphorus poisoning. Material and Methods: Present study was conducted in the department of Forensic Medicine, S.N. Medical College & Hospital, Agra during the period of 18 months (February 2011 to July 2012). Total 160 patients were enrolled after applying inclusion and exclusion criteria. Peradeniya Organophosphorus Poisoning Scale was applied to all study subjects. Result and Observation: Majority of patients were married (70%) and male (64%). About 42% of cases belong to the age group 21–30 years. About 1/3rd of the cases had low socioeconomic status and about 1/3rd cases were farmers by occupation. On applying Peradeniya Organophosphorus Poisoning (POP) Scale, about one third of patients had tachypnoea, followed by impaired consciousness (29%). Serum/ plasma cholinesterase level showed higher mortality in patients having suppressed cholinesterase activity (< 4000 IU/L). Conclusion: Organophosphorus poisoning diagnosed at early stages of poisoning determining pseudocholinesterase activity form a reliable diagnostic test for management and can serve as lives saving tool.

Predictors of the need for Intensive Care Unit admission in acute organophosphorus poisoning: One year prospective study

Background: Organophosphorus (OP) poisoning is a very serious condition that needs rapid intervention and treatment. It can result from occupational, intentional or accidental exposure. Clinical manifestations include muscarinic, nicotinic and central effects which may be life threatening increasing the need for intensive care unit (ICU) management. Aim: The present study aims to identify the predictors which help in making timely decisions regarding transferring the patients for intensive care managements in acute organophosphorus poisoning. Material & Methods: A prospective study included all 404 organophosphorus poisoning cases that were admitted to Menoufia Poison Control Center; Menoufia University Hospitals within the period from the beginning of January 2018 till the end of December 2018. Diagnosis of OP poisoning was based on history of exposure to OP compounds, characteristic clinical manifestations, low serum pseudo cholinesterase levels and detection of OP in the biological fluids by thin layer chromatography. Results: Organophosphorus poisoning was the 2nd common cause of poisoning (15.02% - 404 cases out of 2689) among cases admitted to Menoufia Poison Control Center during the period of the study. Majority of the cases managed at MPCC department while 83 patients (20.54%) needed ICU admission. Most of the cases were suicidal and 94.31% were by oral exposures. 51.98% of the cases were poisoned by the liquid form of OP. Females outnumbered males. The majority of the cases were young students and single. There was statistically significant relation between pseudo cholinesterase activity and severity of the case according to POP classification (p value < 0.001), the more the severity of poisoning the more suppression of pseudo cholinesterase level in the serum. Severe degree of POP classification, presence of hypoxia (< 50 mmHg), convulsions, and severe affection of serum cholinesterase activity were significantly predictors for patients who needed ICU admission. Conclusions: Severe degree of POP classification, presence of hypoxia, convulsions, and severe affection of serum cholinesterase activity are important predictors for ICU admission in OP poisoning.

Protective effects of glycyrrhizin on sub-chronic diazinon-induced biochemical, hematological alterations and oxidative stress indices in male Wistar rats

The aim of this study was to elucidate the protective effect of glycyrrhizin on diazinon-induced changes in body and organ weights, blood hematology, lipid profile, biochemistry parameters and tissue markers of oxidative stress in male Wistar rats over a 7-week period. Rats were orally given sublethal dose of diazinon (10 mg/kg daily; 0.008 LD50), while glycyrrhizin (25 mg kg−1 daily) was given alone or in combination with diazinon. At the end of 7th week, statistically significant decrease of pseudocholinesterase activity was detected when diazinon- and glycyrrhizin + diazinon-treated groups were compared to the control group. Diazinon treated rats showed weight loss and organ weight changes which were comparable to other groups. There was a statistically significance in hematological indices except mean corpuscular hemoglobin (MCH) when diazinon treated group was compared to glycyrrhizin + diazinon treated rats. Glycyrrhizin protected the liver and kidney from diazinon toxic effects with significantly decrease in serum aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and lactate dehydrogenase activities as well as ameliorated hepatic and renal function indices (such as bilirubin, total protein, albumin, BUN, creatinine glucose). In addition, glycyrrhizin minimized the hazardous effect of diazinon on plasma lipids and lipoproteins. The protective effects of glycyrrhizin were confirmed by tissue markers of oxidative stress analysis as glycyrrhizin in combination diminished malondialdehyde and glycyrrhizin alone or in combination enhanced thiol group and the ferric reducing power. In accordance to these results, our observations demonstrated the beneficial effects of glycyrrhizin in reducing the toxicity of diazinon.

Blood Plasma Pseudocholinesterase as a Potential Biomarker of Autoimmune Diseases

We studied the blood plasma butyrylcholinesterase (BChE, pseudocholinesterase) activity as a potential marker for differentiating such autoimmune pathologies as type 1 diabetes mellitus (DM1), autoimmune thyroiditis (AIT) and rheumatoid arthritis (RA) from diseases having similar symptoms but different etiology. The blood plasma pseudocholinesterase activity was analyzed for patients with different types of diabetes mellitus. We showed its fivefold increase in DM1 compared to the control group, while in the second type of diabetes, which is metabolic pathology, it decreases two times. It was demonstrated that the activity of blood plasma BChE in patients with AIT and RA also increased fivefold compared to the group of patients without autoimmune disorders. Thus, the butyrylcholinesterase activity increases in diseases of an autoimmune nature, whereas in metabolic pathology it has the tendency to decrease; it indicates the adequacy of the selected criterion for the further development of a screening test-system that would allow differentiation of autoimmune diseases from the diseases of another origin, but with similar symptoms.

Permethrin drastically affects the developmental cycle of the non-target slime mould Dictyostelium discoideum

The use of pyrethroids has increased throughout the world over the past few decades, as organophosphate, carbamate and organochlorine insecticides are being phased out. Permethrin is widely used in the USA for crops treatment, at concentrations around 750 × 103 μg/L. In our study 3.6 μg/L permethrin decreases the fission-rate and the fruiting bodies formation of slime mould Dictyostelium discoideum. Whereas 3.6 × 104 μg/L kills the 100% of amoebae, showing a 24 h-LC50 = 96.6 μg/L. This concentration induces an increase in the pseudocholinesterase activity as well as in both butyrylcholinesterase and heat-shock-protein 70 presence. Our results highlight the high sensitivity of Dictyostelium to permethrin, at concentration of about 105 lesser than what used for agricultural pest control. If we match our results on 6 days of exposure, with the permethrin relatively slow permanence (30 days) in the aerobic soil, as well as the higher effect of permethrin than organophosphate, carbamate and organochlorine pesticides on D. discoideum, the damage on the dictyostelids community, by use of permethrin, is clear. Our data suggest that, if the sustainable agriculture implementation is a topic of the modern “industrial” farming, the permethrin cannot represent a reliable alternative to organochlorine, organophosphate or carbamate pesticides, in implementing Integrated Pest Management programmes.

A Comparative Study of Pseudocholinesterase Activities in Relation to Transaminases, GGT and ALP in Liver Disorder in Hospital Based Study

Objective: To compare pseudocholinesterase activities in relation to transaminases, GGT and ALP in liver diseases. Method: A prospective study was conducted at College of Medical Sciences –Teaching Hospital (CMS-TH), from May 2011 to May 2013 with 25 healthy (controls) and 25 diagnosed cases each of carcinoma of liver, cirrhosis of liver, infective hepatitis and obstructive jaundice among both sexes of same age group attending medical outpatient and inpatient departments. Serum pseudocholinesterase and other liver function test parameters were performed with semi - autoanalyzer and Roche Hitachi 902 respectively. Result: Pseudocholinesterase level was significantly decrease in the order of control (mean ± SD = 6865.12 ± 928.41) > obstructive jaundice (mean ± SD = 5539 ± 791.05) > infective hepatitis (mean ± SD = 3800.69 ± 764.17) > cirrhosis of liver (mean ± SD = 1735.16 ± 433.82) > carcinoma of liver (mean ± SD = 1369.48 ± 276.64). The difference in the means was statistically significant (p<0.001). Similarly aspartate transaminase (AST) (Mean ± SD= 311.48 ± 177.15) and alanine transaminase (ALT) (Mean ± SD = 491.36 ± 308.92) were higher in hepatitis but in carcinoma of liver the AST (Mean ± SD = 292.55 ± 92.85) level was higher than ALT (Mean ± SD = 179.24 ± 70.25). The difference in the means was statistically significant (p<0.001). AST level was 1.6 time higher than ALT. alkaline phosphatase (ALP) (Mean ± SD = 419.39 ± 90.49) and gamma glutamyl transaminase (GGT) (Mean ± SD = 257.81 ± 68.29) level were higher in obstructive jaundice and GGT (Mean ± SD = 195.54 ± 107.75) level was found to be higher in carcinoma of liver. The difference in the means was statistically significant (p<0.001) Conclusion: There was significant decrease in pseudocholinesterase level in carcinoma of liver followed by cirrhosis of liver and less so in infective hepatitis. AST and ALT level were higher in hepatitis cases. The level of AST was found higher in carcinoma of liver than ALT. In obstructive jaundice ALP and GGT was raised and statistically significant. GGT level was raised in carcinoma of liver. Pseudocholinesterase level was found to be normal in obstructive jaundice. The study results indicated that with more severe liver cell destruction or cell degeneration, there was corresponding significant decrease in the level of pseudocholinesterase, which could be used as diagnostic marker of liver disease.

Synthesis and biodegradation of di-vinyl monomers containing different antimicrobial agents for use in dental adhesive systems

Event Abstract Back to Event Synthesis and biodegradation of di-vinyl monomers containing different antimicrobial agents for use in dental adhesive systems Yasaman Delaviz1* and J Paul Santerre1, 2* 1 University of Toronto, Institute of Biomaterials and Biomedical Engineering, Canada 2 University of Toronto, Faculty of Dentistry, Canada Introduction: More than 50% of dental restorations placed annually are resin composites[1]. However, these materials experience significant biological breakdown in the oral cavity that is believed to be facilitated by oral bacteria which migrate within the margin between the tooth and restorative material. Ciprofloxacin (CF) and Metronidazole (MN) are two antimicrobial agents with potential to manage oral bacterial in the margin environment[2],[3] Previous work reported on the synthesis of CF derived vinyl monomers for adhesives [4]. The objectives of the current work are to synthesize an antimicrobial di-vinyl monomer that will release MN upon hydrolytic degradation, and to formulate adhesive systems containing a combination of both MN and CF derived di-vinyl monomers. Methods: A lysine/hydroxyl-methyl methacrylate (HLH) derivative was synthesized [5]. Using carbodiimide chemistry, the hydroxyl moiety of MN was coupled to HLH acidified ester, yielding HLH-MN. The monomer was characterized by nuclear magnetic resonance. Biodegradation studies (0.1mM) of HLH, HLH-MN and commercial Bisphenol A-glycidyl methacrylate (BisGMA) (n=9, repeated 3 times) were carried out at 37⁰C in buffer or enzyme solution (containing cholesterol esterase activity and pseudocholinesterase activity) for 4 days and solutions characterized by high performance liquid chromatography (HPLC)[5],[6]. Preliminary formulations of CF and MN derived monomers were light cured (1min) using camphorquinone/2-(dimethyl-amino) ethyl methacrylate photo-initiator system, with commercial monomers BisGMA and 2-hydroxyethyl methacrylate (HEMA)[4]. Gel contents were determined and cell toxicity compared using human gingival fibroblasts. Results and Discussion: HLH-MN structure was confirmed by 1H-NMR (Fig 1). The amount of MN released was not significantly different between the buffer or enzyme condition (Fig 2a), whereas it was for BisGMA[7]. HLH-MN was more stable than BisGMA under enzymatic conditions (Fig 2b). The rate of MN released in buffer (4.091 µM/day, r2 = 0.99) was much greater than CF (0.039 µM/day, r2 = 0.86). The linkage between the backbone and MN is an ester while CF is coupled via a more stable amide. This will play to the advantage of each of the drugs relative to minimum inhibitory concentrations (MICs) for Streptococcus mutans, (0.7 µg/mL for CF vs 700 µg/mL for MN). The gel content for cured adhesives with weight percent values for MN:CF:Hema:BisGMA of 5:10:30:55; 10:5:30:55, and 15:15:15:55 were 99.2% (±0.5), 99.0% (±0.7) and 96.0% (±2.8), respectively. These high conversion states are anticipated to yield good cell compatibility in on-going work. Figure 1. 1H-NMR(CDCl3, 400MHz) of HLH-MN, the drug MN is highlighted in blue. Figure 2. Degradation (a) by-products MN and BisHPPP released and (b) remaining monomer in solution, under buffer (DPBS) or enzyme conditions. Conclusion: HLH-MN, which polymerizes with a high degree of cross-linking, is more hydrolytically stable in comparison to BisGMA and releases MN upon degradation. On-going work is assessing the efficacy of the drug release for the combination systems and determining an optimal formulation of the two drug monomer adhesive system with respect to mechanical, chemical and biological stability. The authors would like to thank Dr. Meilin Yang for his scientific input and expertise in chemistry; NSERC CGS and NSERC Discovery Grant #360520

Biodegradation of dental adhesive polymers containing ciprofloxacin derived monomers

Event Abstract Back to Event Biodegradation of dental adhesive polymers containing ciprofloxacin derived monomers Yasaman Delaviz1* and J Paul Santerre1, 2* 1 University of Toronto, Institute of Biomaterials and Biomedical Engineering, Canada 2 University of Toronto, Faculty of Dentistry, Canada Introduction: Despite their popularity[1], resin composites have limited longevity in the oral cavity due to chemical hydrolysis that is believed to be facilitated in part by bacterial hydrolases within the margin of the tooth and restorative material [2][3]. To overcome this challenge, a pro-biochemical approach is being investigated where a drug monomer (DM) is introduced into resin adhesives, enabling the release of antimicrobial agents if the materials are degraded by salivary enzymes. The objective of this study was to assess the degradation of a formulated adhesive with 15wt% DM, and compare it to a control (Bis-Hema) containing the commercial monomers Bisphenol A glycidyl methacrylate (BisGMA) and 2-hydroxyethyl methacrylate (HEMA). Methods: The antibiotic ciprofloxacin (CF) is chemically coupled to the backbone of a di-vinyl lysine monomer, referred to as HLH. The DM is synthesized by covalently coupling a CF/polyethylene glycol (PEG) complex via a pendant acid group on HLH[2]. Adhesive samples (2mm D, 1mm H) were formulated and light cured (1 min/side) in Teflon moulds using 0.5wt% camphorquinone and 1wt% dimethylamino-ethyl methacrylate as initiator system (Tab 1). Gel content (in dichloromethane) and swell ratio (in water) were determined (n=5) after 48 hrs of incubation. Contact angles (n=15, repeated 3 times) were measured by means of a goniometer using deionized water (Tab 1). Biodegradation studies (n=9, repeated 3 times) were performed by by incubating with either DPBS or enzyme solution (containing cholesterol esterase activity and pseudocholinesterase activity), for 28 days[3]. Enzyme activity was maintained by daily replenishment following previously established protocols[3],[4]. Degradation by-products were isolated by high performance liquid chromatography (HPLC). Table 1. Summarizing composition, physical property and contact angle of the three formulations (1:BisHEMA, 2:DM, 3:HLH) used in the biodegradation study;±SD. Results and Discussion: DM is about ~50x more hydrolytically stable than BisGMA[2], however the addition of the DM increased the amount of BisHPPP (terminal degradation by-product of BisGMA) released in DPBS (Fig 1a). In the presence of enzyme, there is no significant difference in the amount of BisHPPP released between the control and the DM containing formulation, but degradation is 3x higher than with DPBS (Fig 1b). Interestingly, the non-PEG precursor (i.e. HLH formulation) significantly enhanced stability (i.e. lower BisHPPP), suggesting that the lysine chemistry promotes stability. The HLH formulation has the lowest water swell ratio (Tab 1), which would also predispose it to less hydrolysis. There was no significant difference in the CF released for buffer vs enzyme (Fig 1c), suggesting that the enzyme has limited access to the pseudo-amide linkage, possibly due to steric hindrance from the bulky pendent structure of CF[5],[6]. Figure 1. Terminal BisHPPP released under (a) buffer and (b) enzyme condition. (c) Terminal CF released from DM formulation for buffer and enzyme condition. Values significantly different are labeled as * (p<0.05), ±SD. Conclusion: While the HLH component contributes to stability of the adhesive, the PEG element enables CF release via simple hydrolysis when BisGMA undergoes degradation in an enzymatic environment. On-going work is investigating the efficacy of the released drug in the presence of streptococcus mutans. NSERC CGS and NSERC Discovery Grant #360520

Evaluation of Organophosphorus Poisoning: Case Series

Organophosphate insecticide compounds inhibit both acetyl cholinesterase and pseudocholinesterase activities. Acute organophosphate insecticide poisoning can manifest three different phases of toxic effects namely, acute cholinergic crisis, intermediate syndrome (IMS), and delayed polyneuropathy. Diagnosis is based on history of exposure and clinical manifestations. Management is beneficial with supportive measures along with specific antidotes. In this case reports, two patients with organophosphate insecticide poisoning are described. Both patients tried to commit suicide by ingesting an unknown amount of organophosphorus poison and both of them have developed intermediate syndrome. But one patient collapsed due to cardiac arrest and other patient was discharged with no complaints. Treatment for both patients mainly included atropine and parlidoxime.

Pseudocholinesterase as a predictor of mortality and morbidity in organophosphorus poisoning.

Background:Organophosphorus (OP) pesticide poisoning is a major clinical and public health problem in India. Mortality rate remains high at 15%–30%.Aims:This prospective, observational study examines the relationship between pseudocholinesterase (PChE) activity and morbidity and mortality in OP poisoning.Setting and Design:OP poisoning cases admitted to a tertiary care center Intensive Care Unit (ICU) over 5 years from 2010 to 2014 were studied.Methods:Patients <16 years of age, those on steroids and those with neuromuscular weakness, were excluded from the study. Serum PChE level at admission was estimated and the severity of poisoning assessed accordingly. Primary outcome measures were ICU length of stay and ventilator-free days. Secondary outcome measures included vasopressor-free days, amount of atropine given, hospital length of stay, and ICU mortality.Results:There were 37 patients included in the study, aged between 24 and 44 years, of which 65% were male. They were divided into two groups according to PChE levels. Group A with PChE levels more than 1000 IU/L had twenty patients and Group B with levels <1000 IU/L had 17 patients. Group B had longer ICU length of stay (P < 0.001) and fewer ventilator-free days (P < 0.001). They also had a fewer vasopressor-free days and a longer stay in hospital.Conclusions:PChE level at presentation is a reliable indicator of the severity of OP poisoning and a predictor of the need for mechanical ventilation and the duration of stay in the ICU.

The role of PON1 and CYP2D6 genes in susceptibility to organophosphorus chronic intoxication in Egyptian patients

BackgroundParaoxonase-1 (PON1) activity toward organophosphorus(OP) compounds shows inter-individual variations, rendering the identification of individuals’ PON1 allozymes valuable in treating patients suffering from organophosphorus intoxication. One of the most important cytochrome P450 monooxygenases (CYPs) is CYP2D6. The CYP2D6 G1934A polymorphism leads to good, poor or no enzyme activity. Genetic testing helps identification of high risk individuals as well as management of chronic intoxicated patients. Objectiveto investigate a possible association between genetic polymorphisms of PON1 Q192R, and CYP2D6 G1934A as well as PON1 and pseudo-cholinesterase (PChE) enzyme activity levels and chronic organophosphate exposed patients, and hence, susceptibility for organophosphorus chronic poisoning. Design and methodsThirty chronic organophosphate exposed farm workers were compared to 29 healthy controls as regards PON1 Q192R and CYP2D6 G1934A polymorphisms using PCR-RFLP technique. Also serum PON1 and PChE activities were determined spectrophotometrically. ResultsSerum PChE was significantly reduced in chronic intoxicated patients compared to the control group (p=0.02), while PON1 activity was increased, but just failed to reach significance (p=0.06). PON1 192 RR genotype and R allele were significantly increased in chronic OP intoxicated patients (p=0.005 &p=0.002 respectively). CYP2D6 1934A allele was significantly increased in chronic OP patients (p=0.045). combining the two SNPs showed a significant statistical difference between the two groups with PON1QQ and CYP2D6 GG genotypes being more represented in the healthy controls (p=0.001). Fatigue and motor weakness were the most prevalent neurological symptoms seen in chronic cases (56.7%), followed by headache and lacrimation (30% each), depression (23%), tingling and sensory symptoms (20%), sleep disorders and limb pain (13%).The mean duration of environmental exposure to organophosphates was 7.7±5.2years and no association was found between chronic symptoms of intoxication and duration of exposure, provided that all workers were exposed for at least 3 years. ConclusionPON1 192RR genotype and CYP2D6 1934A allele were found to be related to the susceptibility to organophosphate chronic toxicity in Egyptians. Larger scale gene-environmental interaction studies are recommended to confirm results and Genotyping is recommended during selection of agricultural pesticide workers to exclude high risk group.

Pseudocholinesterase as a prognostic marker for liver disorder

Background: Liver is the main source of pseudo cholinesterase. It is a non-specific cholinesterase found in the blood plasma and may be reduced in patients with advanced liver diseases. Measurement of serum pseudo cholinesterase activity serves as a sensitive indicator of synthetic capacity of the liver and can be used as a prognostic marker for carcinoma.Objective: To study pseudo cholinesterase activities in liver diseases.Method: A prospective study was conducted at College of Medical Sciences Teaching Hospital (CMS-TH), from May 2011 to May 2013 with 25 controls and 25 diagnosed cases each of carcinoma of liver, cirrhosis of liver, infective hepatitis and obstructive jaundice among both sexes of same age group attending medical outpatient and inpatient departments. Serum pseudo cholinesterase and other liver function tests were performed with semi-auto analyzer and Roche Hitachi 902 respectively.Results: Pseudo cholinesterase level was markedly decreased in carcinoma of liver (mean ± SD = 1369.48 ± 276.64 IU/L) followed by cirrhosis of liver (mean ± SD = 1735.16 ± 433.82 IU/L), infective hepatitis (mean ± SD = 3800.69 ± 764.17 IU/L), obstructive jaundice (mean ± SD = 5539 ± 791.05 IU/L) when compared with controls (mean ± SD = 6865.12 ± 928.41 IU/L). The difference in the means was statistically significant (p &lt;0.001).Conclusion: There was significant decrease in pseudo holing esterase level in carcinoma of liver followed by cirrhosis of liver while less so in infective hepatitis. In obstructive jaundice the enzyme level was found to be decreased but higher than other liver diseases. The results indicated that with more severe liver cell destruction or cell degeneration, there was corresponding significant decrease in the level of pseudo cholinesterase, which could be used as diagnostic marker of liver disease.Journal of Kathmandu Medical College Vol. 3, No. 4, Issue 10, Oct.-Dec., 2014Page: 131-135

Paraoxonase 1 and cytochrome P450 polymorphisms in susceptibility to acute organophosphorus poisoning in Egyptians

BackgroundOrganophosphates are the basis of many insecticides, herbicides, and nerve agents. They were listed as highly acutely toxic agents. Findings in knockout mice suggest that paraoxonase 1 may modulate the toxicity resulting from exposure to organophosphorus compounds. In human, there is no enough data about genetic modulation of acute organophosphorus intoxication. CYP2D6 is involved in the metabolism of about 30% of xenobiotics. Prompt accurate management of OP acute intoxication can promote patient's survival. Design and methodsForty acute organophosphorus intoxicated patients were divided according to presence of clinical toxicity manifestations and serum level of pseudo-cholinesterase into two groups of acute symptomatic and acute asymptomatic patients. A third group of 29 healthy volunteers served as control. Paraoxonase 1 Q192R and CYP2D6 G1934A polymorphisms, (QQ, QR, and RR for PON1) and (GG, GA, and AA for CYP2D6), were studied using polymerase chain reaction-restriction fragment length polymorphism technique. Serum paraoxonase 1 and pseudo-cholinesterase activities were measured spectrophotometrically. ResultsSerum pseudo-cholinesterase was significantly reduced in both acute intoxication groups compared to the controls (p=0.000). Paraoxonase 1 was significantly reduced in the symptomatic acute intoxication patients in comparison to the asymptomatic group (p=0.002). There was a significant increase in paraoxonase 1 192 RR genotype and R allele in the symptomatic patients in comparison to the controls and asymptomatic patients (p=0.006 and p=0.01, respectively). For CYP2D6 G1934A genotypes and alleles, no significant difference was found between groups (p=0.3 and p=0.18, respectively). However, one case of the two recorded fatalities was for a symptomatic female patient with the only traced AA genotype. The combination of both single nucleotide polymorphisms revealed a significant distribution difference between groups, with QQ+GG genotypes being more represented in the controls, while RR+GA genotypes were exclusively present in the group of symptomatic patients (p=0.04), none of the participants was found to have RR+AA genotypes.Some nicotinic (fasciculation and weakness), and muscarinic symptoms (bronchospasm, salivation, lacrimation, and diarrhea), increased with high significance in the symptomatic group compared to the asymptomatic one (p<0.001 for all). Convulsions also showed significant increase (p=0.02). ConclusionParaoxonase 1 Q192R modulates patient's response, and CYP2D6 may be related to the acute organophosphorus intoxication in the context of other genetic-environmental factors. Paraoxonase 1 enzyme level is related to symptom severity in acute OP poisoning, while pseudo-cholinesterase level indicates exposure to OP rather than severity of clinical manifestations.