In Vitro Inhibition of Blood Cholinesterase Activities by Dichlorvos in Farmworkers Previously Exposed to Pesticides

Odisho, Simona Khamo; Mohammad, F. K.

doi:10.21608/ejchem.2023.210539.7968

Cited by 2 publications

(6 citation statements)

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“…We used an electrometric method to determine plasma ChE by incubating 0.2 ml of plasma aliquot with a reaction mixture containing 3 ml of distilled water, 3 ml of barbital-phosphate buffer (1.237 g sodium barbital, 0.163 g potassium dihydrogen phosphate, and 35.07 g sodium chloride/L of distilled water, pH 8.1) [24,25]. After measuring the pH1 of the mixture with the glass electrode of a pH meter (pH700, Eutech Instruments, Singapore), 0.1 ml of 7.1% aqueous solution of acetylcholine iodide was added, and the mixture was incubated in a water bath at 37 ºC for 20 minutes.…”

Section: Determination Of Plasma Che Activitymentioning

confidence: 99%

“…Aliquots of plasma samples obtained from the controls and the three RA groups (10/group) were pooled separately. We used the technique of 10-min in vitro incubation of a ChE inhibitor (in this case the organophosphate dichlorvos) with 0.2 ml of pooled plasma aliquot to induce enzyme activity inhibition as reported before [24,25]. An aqueous solution of dichlorvos (Dichlorvos 50% EC, Nicoz, China) was freshly prepared for in vitro inhibition usage at final concentrations of 0.25 or 0.5 μM in the plasma-ChE reaction mixture (6.3 mL).…”

Section: In Vitro Inhibition Of Plasma Che Activity By Dichlorvosmentioning

confidence: 99%

“…An aqueous solution of dichlorvos (Dichlorvos 50% EC, Nicoz, China) was freshly prepared for in vitro inhibition usage at final concentrations of 0.25 or 0.5 μM in the plasma-ChE reaction mixture (6.3 mL). These concentrations of dichlorvos have been previously used for in vitro blood ChE inhibition [25,26]. The plasma aliquot-dichlorvos reaction mixtures were incubated in a water bath at 37 ºC for 10 minutes to initiate enzyme inhibition.…”

Section: In Vitro Inhibition Of Plasma Che Activity By Dichlorvosmentioning

confidence: 99%

“…Aliquots of plasma samples obtained from the controls and the three RA groups (10 each) were pooled separately to be used in this experiment using dichlorvos as an inhibitor [25,26]. The designated pooled plasma samples were incubated in vitro with dichlorvos at 0.25 μM for 5, 10, 15, 30, and 60 minutes, with the plasma ChE activity at 0-time without dichlorvos to be considered 100% baseline activity value [25]. Plasma ChE activity was determined at each time point in duplicate, and a suitable blank was included at each incubation time.…”

Section: Kinetic Determination Of In Vitro Plasma Che Inhibition By D...mentioning

confidence: 99%

“…The in vitro decline of plasma ChE activity by dichlorvos vs. time (0 to 60 minutes) was used to apply steadystate kinetics for the following measurements as described in detail earlier [25]:…”

Section: Kinetic Determination Of In Vitro Plasma Che Inhibition By D...mentioning

confidence: 99%

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Plasma Cholinesterase Activity in Patients With Rheumatoid Arthritis and Toxoplasmosis

Abdullah,

Eassa,

Mohammad

2023

Cureus

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Background and objectiveRheumatoid arthritis (RA) is a chronic autoimmune disease causing synovium inflammation and functional impairment. Toxoplasmosis is an intracellular zoonotic parasitic infection and a risk factor in immunosuppressed diseases including RA. The involvement of the cholinergic mechanism is not clear when both diseases exist in combination. This study aimed to examine plasma cholinesterase (ChE) activity in patients suffering from RA with concomitant toxoplasmosis, taking into account the enzyme susceptibility to in vitro inhibitory challenge with the organophosphate dichlorvos in RA patients. MethodsThis was a case-control study involving 88 RA patients and 61 healthy controls of both genders. The RA patients were allocated into three groups. The first group received no therapy (n=14), the second group received conventional anti-arthritis therapy (n=49), and the third group received conventional + biologic therapy (n=25). Plasma ChE activity was determined by an electrometric method. Plasma samples were screened for Toxoplasma gondii (T. gondii) infection, using ELISA T. gondii antibodies IgG and IgM. In vitro inhibition of plasma ChE activity was assessed by incubating the samples with dichlorvos at 0.25 and 0.5 μM. The time-dependent dichlorvos (0.25 μM)-induced plasma ChE inhibition and its kinetics were determined. ResultsThe RA patients comprised 76 (86.4%) females and 12 males (13.6%), whereas healthy controls included 22 (36.1%) females and 39 (63.9%) males. The rates of toxoplasmosis IgG positivity in controls and RA patients were 26.2% and 39.8%, respectively. Plasma ChE activity in patients with RA was significantly higher than that in the control group, by 16%. Plasma ChE values of RA patients with conventional therapy and conventional + biologic therapy were higher than that of the control group, by 18% and 27%, respectively. Odds and risk ratios of elevated plasma ChE activity (20%) in RA patients with therapy indicated that high plasma ChE activity among RA patients with therapy is a risk factor. The plasma ChE activity of T. gondii IgG-positive RA patients was not significantly different from that of the IgG-negative ones. Dichlorvos at 0.25 and 0.5 μM significantly inhibited in vitro plasma ChE activity in controls and RA patients. The rates of plasma ChE inhibition by dichlorvos were lower in the RA groups with conventional therapy in comparison with those in the control group (77% vs. 91%). Examining the dichlorvos time-dependent ChE inhibition kinetics, RA groups showed increases in the half-life of inhibition by 23.6% to 32.7% and the total inhibition time by 23.5% to 32.5%, together with decreases in the inhibition rate constant by 19% to 24.5%, an indication of reduced inhibition rate of plasma ChE activity compared to that of the control group. ConclusionsThe autoimmune nature of RA and its chronicity might have contributed to the increase in plasma ChE activity among the patients. This increase in enzyme activity could be a risk factor in RA patients undergoing conventi...

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Section: Determination Of Plasma Che Activitymentioning

confidence: 99%

Section: In Vitro Inhibition Of Plasma Che Activity By Dichlorvosmentioning

confidence: 99%

Section: In Vitro Inhibition Of Plasma Che Activity By Dichlorvosmentioning

confidence: 99%

Section: Kinetic Determination Of In Vitro Plasma Che Inhibition By D...mentioning

confidence: 99%

Section: Kinetic Determination Of In Vitro Plasma Che Inhibition By D...mentioning

confidence: 99%

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Plasma Cholinesterase Activity in Patients With Rheumatoid Arthritis and Toxoplasmosis

Abdullah,

Eassa,

Mohammad

2023

Cureus

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The Potential Risk of Reduced Serum Cholinesterase Activity in COVID-19 Patients Suffering From Cytokine Storm

M. Raouf,

Mohammad,

Merza

2024

Cureus

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Background and objective Several blood biochemical parameters are used to biomonitor coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Reduced serum cholinesterase (ChE) has been suggested to be a predictive indicator of the severity and outcome of COVID-19 infection. This study aimed to examine serum ChE activity in hospitalized and terminally ill COVID-19 patients with cytokine storm and evaluate the enzyme for the in vitro ChE-inhibitory activity of the organophosphate dichlorvos. Methods We determined the serum ChE activity, electrometrically, among hospitalized COVID-19-cytokine storm patients and their non-cytokine storm counterparts. Aliquots of serum samples from healthy volunteers, COVID-19-cytokine storm patients, and non-cytokine storm COVID-19 patients were pooled separately. They were incubated in vitro for 10 minutes with dichlorvos at 0.25 or 0.5 μM. Serum samples from the three groups were subjected to ChE inhibition temporally (5-60 minutes) by 0.25 μM dichlorvos to evaluate the kinetics of enzyme inhibition using steady-state kinetics. Results Of the 165 hospitalized patients with COVID-19, 33 (20%) suffered from the cytokine storm. Serum ChE activity of female COVID-19 patients with cytokine storm was significantly lower than that of the non-cytokine storm counterparts. Risk analysis of reduced serum ChE activity (≥20%) among the 33 COVID-19 patients with cytokine storm compared to 111 non-cytokine storm COVID-19 patients revealed that the former were significantly at risk of reduced enzyme activity. In vitro, dichlorvos at 0.25 μM and 0.5 μM significantly inhibited serum ChE activity in all the groups. The COVID-19-cytokine storm group was the least affected. Dichlorvos at 0.25 μM progressively (5-60 minutes) inhibited serum ChE activity. The inhibition kinetic parameters in COVID-19-cytokine storm patients showed a decrease in the half-life of inhibition (14.54%), inhibition rate (51.46%), and total inhibition time (14.55%). Conclusions Reduced serum ChE in COVID-19 patients with cytokine storm could be adopted as a potential additional laboratory examination tool for bedside risk assessment. The in vitro inhibition profile of serum ChE activity by dichlorvos in COVID-19-cytokine storm patients suggests reduced susceptibility of the enzyme to inhibition. The response of COVID-19 patients to ChE-inhibiting medications should be cautiously evaluated with prior in vitro tests.

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In Vitro Inhibition of Blood Cholinesterase Activities by Dichlorvos in Farmworkers Previously Exposed to Pesticides

Cited by 2 publications

References 0 publications

Plasma Cholinesterase Activity in Patients With Rheumatoid Arthritis and Toxoplasmosis

Plasma Cholinesterase Activity in Patients With Rheumatoid Arthritis and Toxoplasmosis

The Potential Risk of Reduced Serum Cholinesterase Activity in COVID-19 Patients Suffering From Cytokine Storm

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