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Biomedical Chromatography : BMC Jun 2023Recently, the main interest of analytical chemistry researchers has been the development of green analytical methods to minimize harmful effects on the environment and...
Recently, the main interest of analytical chemistry researchers has been the development of green analytical methods to minimize harmful effects on the environment and natural life. Therefore, an RP-HPLC method was developed and assessed regarding its greenness criteria using three greenness assessment tools: an analytical eco-scale, an analytical greenness metric approach and a green analytical procedure index. This method aims to separate and quantitatively determine three co-administered drugs, namely pyridostigmine bromide (PYR), 6-mercaptopurine (MRC) and prednisolone (PRD), in their tertiary mixture and spiked human plasma. These drugs are co-administered to manage myasthenia gravis autoimmune disease. The separation was done using a C column and a gradient elution of a mixture of 0.1% H PO aqueous solution (pH 2.3) and methanol. The flow rate was adjusted to 1 ml/min and detection was done at 254 (for PYR and PRD) and at 330 nm (for MRC). The lower limits of quantitation were 15, 2, and 5 μg/ml for PYR, MER and PRD, respectively. Linear correlations were obtained and found to be near 1. In addition, the proposed method was validated according to the US Food and Drug Administration's instructions, and the results proved its success to determine the three studied drugs in their tertiary mixture and spiked human plasma.
Topics: United States; Humans; Chromatography; Myasthenia Gravis; Chromatography, High Pressure Liquid
PubMed: 36882891
DOI: 10.1002/bmc.5615 -
American Journal of Physiology.... Aug 2019Diabetic patients are more susceptible to myocardial ischemia damage than nondiabetic patients, with worse clinical outcomes and greater mortality. The mechanism may be...
Diabetic patients are more susceptible to myocardial ischemia damage than nondiabetic patients, with worse clinical outcomes and greater mortality. The mechanism may be related to glucose metabolism, mitochondrial homeostasis, and oxidative stress. Pyridostigmine may improve vagal activity to protect cardiac function in cardiovascular diseases. Researchers have not determined whether pyridostigmine regulates glucose metabolism and mitochondrial homeostasis to reduce myocardial vulnerability to injury in diabetic mice. In the present study, autonomic imbalance, myocardial damage, mitochondrial dysfunction, and oxidative stress were exacerbated in isoproterenol-stimulated diabetic mice, revealing the myocardial vulnerability of diabetic mice to injury compared with mice with diabetes or exposed to isoproterenol alone. Compared with normal mice, the expression of glucose transporters (GLUT)1/4 phosphofructokinase (PFK) FB3, and pyruvate kinase isoform (PKM) was decreased in diabetic mice, but increased in isoproterenol-stimulated normal mice. Following exposure to isoproterenol, the expression of (GLUT)1/4 phosphofructokinase (PFK) FB3, and PKM decreased in diabetic mice compared with normal mice. The downregulation of SIRT3/AMPK and IRS-1/Akt in isoproterenol-stimulated diabetic mice was exacerbated compared with that in diabetic mice or isoproterenol-stimulated normal mice. Pyridostigmine improved vagus activity, increased GLUT1/4, PFKFB3, and PKM expression, and ameliorated mitochondrial dysfunction and oxidative stress to reduce myocardial damage in isoproterenol-stimulated diabetic mice. Based on these results, it was found that pyridostigmine may reduce myocardial vulnerability to injury via the SIRT3/AMPK and IRS-1/Akt pathways in diabetic mice with isoproterenol-induced myocardial damage. This study may provide a potential therapeutic target for myocardial damage in diabetic patients.
Topics: Animals; Carbohydrate Metabolism; Diabetes Mellitus, Experimental; Diabetic Cardiomyopathies; Glucose; Isoproterenol; Male; Mice; Mice, Inbred C57BL; Mitochondria, Heart; Myocardial Ischemia; Myocytes, Cardiac; Oxidative Stress; Pyridostigmine Bromide
PubMed: 31211620
DOI: 10.1152/ajpendo.00569.2018 -
Photodiagnosis and Photodynamic Therapy Mar 2023Although the mechanism is not clear, the inability of the orbicularis oculi muscle, especially the deeper segment (Horner muscle), is thought to be responsible in...
BACKGROUND
Although the mechanism is not clear, the inability of the orbicularis oculi muscle, especially the deeper segment (Horner muscle), is thought to be responsible in epiphora. This study evaluates the effect of the anticholinergic drug pyridostigmine (Mestinon) in patients with patent but dysfunctional lacrimal drainage system.
MATERIAL AND METHODS
Twenty patients with bilateral epiphora (mean age:60.78 ± 6.49 yrs) were included in this study. Patients with a patent lacrimal irrigation test based on persistent and symptomatic epiphora, wiping >10 times daily or continuous tearing and grade 4-5 epiphora according to Munk scale, showing neuropathic involvement in the orbicularis oculi muscle by the quantitative motor unit potential (MUP) analysis method were evaluated prospectively. Fluorescein dye disappearance test (a semi-quantitative assessment of delayed tear outflow) together with a Schirmer test reading were performed in order to detect dry eye. The patients were evaluated for tear meniscus measurements by anterior segment optical coherence topography (OCT) and non-invasive tear break-up time (NI-BUT) was measured by Oculus Keratograph 5 M. Those with a NI-BUT value above 10 s, without eyelid laxity, previous ocular surgery or ocular surface disease, or nasolacrimal duct obstruction, and who agreed to use the drug were included in the study. Each subject underwent OCT measurements of the lower tear meniscus of both eyes before and 15 mins after taking Mestinon (1 × 60 mg tablet). Upon measurement of the positive effect of the drug on tear meniscus height (TMH), the patients were asked to continue this regime daily for 1 month and then evaluated for relief in their epiphora complaints and any systemic drug side effects.
RESULTS
A total of 20 patients (40 eyes) with bilateral epiphora were included in the study. All eyes had grade 4 Munk-score epiphora, Schirmer's test was within the normal range in all eyes (mean, 14 ± 4 mm), and patent lacrimal irrigation test. The lower mean TMH reductions 15 min after Mestinon in the right and left eyes were 135.41 ± 85.47 and 55.44 ± 61.56 mm, respectively, a statistically significant decrease in both eyes (p = 0.001, p < 0.01). The mean tear meniscus area (TMA) in the right and left eyes was 131.83 ± 68.27 mm and 62.72 ± 50.57 mm, respectively; 15 mins after administration of Mestinon, the mean TMA in the right and left eyes was 77.27 ± 48.34 and 59.18 ± 44.74 mm, respectively (p = 0.001, p < 0.01). The mean decreases of 54.56 ± 39.34 mm in the right eye area and 3.53 ± 42.32 mm in the left eye area were statistically significant (p = 0.041, p < 0.05).
CONCLUSION
Symptomatic relief for epiphora cannot be achieved with known treatment options due to lacrimal pump dysfunction. We found that pyridostigmine (Mestinon) provided relief in patients' complaints of epiphora consistent with a significant reduction in TMH levels.
Topics: Humans; Middle Aged; Aged; Pyridostigmine Bromide; Lacrimal Duct Obstruction; Nasolacrimal Duct; Tomography, Optical Coherence; Photochemotherapy; Photosensitizing Agents
PubMed: 36592783
DOI: 10.1016/j.pdpdt.2022.103240 -
Mutation Research. Genetic Toxicology... Nov 2017Pyridostigmine bromide (PB) is a reversible acetylcholinesterase (AChE) inhibitor and the first-choice for the treatment of symptoms associated with myasthenia gravis...
Pyridostigmine bromide (PB) is a reversible acetylcholinesterase (AChE) inhibitor and the first-choice for the treatment of symptoms associated with myasthenia gravis and other neuromuscular junction disorders. However, evidence suggested that PB could be associated with the Gulf War Illness characterised by the presence of fatigue, headaches, cognitive dysfunction, and musculoskeletal respiratory and gastrointestinal disturbances. Given that a potential neurotoxic effect of PB has not yet been completely elucidated, the present investigation used neural SH-SY5Y cells to evaluate the effect of PB on the cellular viability, cell apoptosis, modulation of the cell cycle, oxidative stress, and genotoxicity variables, which indicate neurodegeneration. As expected, a PB concentration curve based on the therapeutic dose of the drug showed an inhibition of the AChE activity. However, this effect was transient and did not involve differential AChE gene regulation by PB. These results confirmed that undifferentiated SH-SY5Y cells can be used as a cholinergic in vitro model. In general, PB did not trigger oxidative stress, and at a slightly higher PB concentration (80ng/mL), higher levels of protein carbonylation and DNA damage were detected, as determined by the marker 8-deoxyguanosine. The PB genotoxic effects at 80ng/mL were confirmed by the upregulation of the p53 and DNA methyltransferase 1 (DNMT1) genes, which are associated with cellular DNA repair. PB at 40ng/mL, which is the minimal therapeutic dose, led to higher cell proliferation and mitochondrial activity compared with the control group. The effects of PB were corroborated by the upregulation of the telomerase gene. In summary, despite the methodological constrains related to the in vitro protocols, our results suggested that exposure of neural cells to PB, without other chemical and physical stressors did not cause extensive toxicity or indicate any neurodegeneration patterns.
Topics: Cell Line, Tumor; Cell Proliferation; Cell Survival; Cholinesterase Inhibitors; DNA (Cytosine-5-)-Methyltransferase 1; DNA (Cytosine-5-)-Methyltransferases; DNA Damage; DNA Repair; Humans; Mitochondria; Myasthenia Gravis; Neurons; Oxidative Stress; Pyridostigmine Bromide; Tumor Suppressor Protein p53; Up-Regulation
PubMed: 28985942
DOI: 10.1016/j.mrgentox.2017.08.003 -
Toxicology Sep 2018Physostigmine and its analogues neostigmine, pyridostigmine and rivastigmine are carbamates nowadays used in many indications, including antidotal effects against... (Comparative Study)
Comparative Study
BACKGROUND
Physostigmine and its analogues neostigmine, pyridostigmine and rivastigmine are carbamates nowadays used in many indications, including antidotal effects against antimuscarinic poisonings, reversal of competitive neuromuscular block, myasthenia gravis, Alzheimer's disease and prophylaxis against nerve agent intoxications. Use of these medicinal carbamates, but also of carbamate insecticides, created need for research into the potential and mechanisms of action of several antidotes against carbamate poisonings, including anticholinergics and oximes.
AIM
The goal of this experimental study was to ascertain the life-preserving potential of anticholinergics atropine, hexamethonium and d-tubocurarine, oxime HI-6 and their combinations in rats poisoned with physostigmine or pyridostigmine.
MATERIALS AND METHODS
Experiments were performed in Wistar rats. Carbamates were injected subcutaneously (sc) and antidotes intramuscularly (im). Median lethal dose (LD) in animals treated with antidotes were compared to the ones in saline-treated rats and protective ratios (PRs) were calculated. Atropine (5, 10 and 20 mg/kg), hexamethonium (5, 10 and 20 mg/kg), d-tubocurarine (0.005, 0.010 and 0.020 mg/kg) and oxime HI-6 (25, 50 and 100 mg/kg) were used as monotherapies and in dual combinations, where atropine was the obligatory antidote. Biochemical experiments consisted in measuring of the cholinesterase activities in brain, whole blood and diaphragm in rats 5, 15, 30, 60, 120 and 240 min after poisoning with 0.8 LD of physostigmine or pyridostigmine.
RESULTS
All the tested antidotes assured some degree of protection against the two carbamates. Atropine and hexamethonium produced better protection in physostigmine-poisoned rats, while d-tubocurarine and HI-6 were more efficacious in pyridostigmine-intoxicated animals. Oxime HI-6 50 mg/kg reactivated acetylcholinesterase (AChE) in brain inhibited by physostigmine and in diaphragm inhibited by pyridostigmine.
CONCLUSIONS
Mechanism of physostigmine-induced lethal effect is predominantly central and it involves inhibition of brain AChE, while pyridostigmine produces the same effect exclusively outside the central nervous system, by inhibiting AChE in the respiratory muscles. As a consequence, increasing doses of atropine and their combination with hexamethonium assure excellent protection against physostigmine toxicity, while the best protection against pyridostigmine is provided by a strictly peripherally acting antinicotinic d-tubocurarine and bispyridinium oxime HI-6. The oxime acts as antidote against physostigmine and pyridostigmine poisoning by reactivating AChE in the brain and diaphragm, respectively.
Topics: Acetylcholinesterase; Animals; Antidotes; Atropine; Brain; Cholinergic Antagonists; Cholinesterase Reactivators; Diaphragm; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Therapy, Combination; Enzyme Activation; GPI-Linked Proteins; Hexamethonium; Male; Neurotoxicity Syndromes; Oximes; Physostigmine; Pyridinium Compounds; Pyridostigmine Bromide; Rats, Wistar; Tubocurarine
PubMed: 30176331
DOI: 10.1016/j.tox.2018.08.017 -
Toxicology and Applied Pharmacology Aug 2018Many veterans of Operation Desert Storm (ODS) struggle with the chronic pain of Gulf War Illness (GWI). Exposure to insecticides and pyridostigmine bromide (PB) have... (Comparative Study)
Comparative Study
Many veterans of Operation Desert Storm (ODS) struggle with the chronic pain of Gulf War Illness (GWI). Exposure to insecticides and pyridostigmine bromide (PB) have been implicated in the etiology of this multisymptom disease. We examined the influence of 3 (DEET (N,N-diethyl-meta-toluamide), permethrin, chlorpyrifos) or 4 GW agents (DEET, permethrin, chlorpyrifos, pyridostigmine bromide (PB)) on the post-exposure ambulatory and resting behaviors of rats. In three independent studies, rats that were exposed to all 4 agents consistently developed both immediate and delayed ambulatory deficits that persisted at least 16 weeks after exposures had ceased. Rats exposed to a 3 agent protocol (PB excluded) did not develop any ambulatory deficits. Cellular and molecular studies on nociceptors harvested from 16WP (weeks post-exposure) rats indicated that vascular nociceptor Na1.9 mediated currents were chronically potentiated following the 4 agent protocol but not following the 3 agent protocol. Muscarinic linkages to muscle nociceptor TRPA1 were also potentiated in the 4 agent but not the 3 agent, PB excluded, protocol. Although K7 activity changes diverged from the behavioral data, a K7 opener, retigabine, transiently reversed ambulation deficits. We concluded that PB played a critical role in the development of pain-like signs in a GWI rat model and that shifts in Na1.9 and TRPA1 activity were critical to the expression of these pain behaviors.
Topics: Adaptation, Physiological; Animals; Behavior, Animal; Chlorpyrifos; DEET; Disease Models, Animal; Ganglia, Spinal; KCNQ Potassium Channels; Male; Muscle, Skeletal; NAV1.9 Voltage-Gated Sodium Channel; Pain Perception; Pain Threshold; Permethrin; Persian Gulf Syndrome; Pyridostigmine Bromide; Rats, Sprague-Dawley; Receptors, Muscarinic; Signal Transduction; TRPA1 Cation Channel; Time Factors
PubMed: 29803855
DOI: 10.1016/j.taap.2018.05.023 -
Acta Neuropathologica Communications Oct 2022Chemical and pharmaceutical exposures have been associated with the development of Gulf War Illness (GWI), but how these factors interact with the pathophysiology of...
Chemical and pharmaceutical exposures have been associated with the development of Gulf War Illness (GWI), but how these factors interact with the pathophysiology of traumatic brain injury (TBI) remains an area of study that has received little attention thus far. We studied the effects of pyridostigmine bromide (an anti-nerve agent) and permethrin (a pesticide) exposure in a mouse model of repetitive mild TBI (r-mTBI), with 5 impacts over a 9-day period, followed by Gulf War (GW) toxicant exposure for 10 days beginning 30 days after the last head injury. We then assessed the chronic behavioral and pathological sequelae 5 months after GW agent exposure. We observed that r-mTBI and GWI cumulatively affect the spatial memory of mice in the Barnes maze and result in a shift of search strategies employed by r-mTBI/GW exposed mice. GW exposure also produced anxiety-like behavior in sham animals, but r-mTBI produced disinhibition in both the vehicle and GW treated mice. Pathologically, GW exposure worsened r-mTBI dependent axonal degeneration and neuroinflammation, increased oligodendrocyte cell counts, and increased r-mTBI dependent phosphorylated tau, which was found to colocalize with oligodendrocytes in the corpus callosum. These results suggest that GW exposures may worsen TBI-related deficits. Veterans with a history of both GW chemical exposures as well as TBI may be at higher risk for worse symptoms and outcomes. Subsequent exposure to various toxic substances can influence the chronic nature of mTBI and should be considered as an etiological factor influencing mTBI recovery.
Topics: Mice; Animals; Gulf War; Brain Concussion; Pyridostigmine Bromide; Permethrin; Disease Models, Animal; Brain Injuries, Traumatic; Pesticides; Pharmaceutical Preparations
PubMed: 36258255
DOI: 10.1186/s40478-022-01449-x -
Advanced Biology May 2023Gulf War Illness (GWI) results from chemical exposure during the Gulf War, with notable impacts on gastrointestinal motility. Due to the limited demographic impacted by...
Gulf War Illness (GWI) results from chemical exposure during the Gulf War, with notable impacts on gastrointestinal motility. Due to the limited demographic impacted by this ailment, an in-depth investigation of the GWI has yielded little regarding the underlying pathophysiological mechanisms. Here, the hypothesis that exposure to pyridostigmine bromide (PB) results in severe enteric neuro-inflammation, that cascades to disruptions in colonic motility, is tested. The analyses are performed on male C57BL/6 mice that are treated with physiologically similar doses of PB given to GW veterans. When colonic motility is assessed, GWI colons have significantly reduced forces in response to acetylcholine or electrical field stimulation. GWI is also accompanied by high levels of pro-inflammatory cytokines and chemokines, associated with increased numbers of CD40 pro-inflammatory macrophages within the myenteric plexus. Enteric neurons responsible for mediating colonic motility reside within the myenteric plexus, and PB exposure reduced their numbers. Significant smooth muscle hypertrophy is also observed due to increased inflammation. Together, the results show that PB exposure caused functional and anatomical dysfunction, promoting impaired motility within the colon. Achieving a greater understanding of the mechanisms of GWI will allow more refinement in therapeutic options that improve veterans' quality of life.
Topics: Mice; Male; Animals; Pyridostigmine Bromide; Persian Gulf Syndrome; Quality of Life; Mice, Inbred C57BL; Cholinesterase Inhibitors; Inflammation
PubMed: 36802210
DOI: 10.1002/adbi.202200254 -
American Journal of Hypertension May 2019Acetylcholinesterase inhibition prevents autonomic imbalance, reduces inflammation, and attenuates the development of hypertension. Considering that vascular dysfunction...
BACKGROUND
Acetylcholinesterase inhibition prevents autonomic imbalance, reduces inflammation, and attenuates the development of hypertension. Considering that vascular dysfunction is a crucial feature of arterial hypertension, we investigated the effects of chronic administration of acetylcholinesterase inhibitors-pyridostigmine or donepezil-on vascular reactivity of spontaneously hypertensive rats (SHR).
METHODS
Endothelium-dependent relaxant responses to acetylcholine (ACh) and contractile responses induced by electric field stimulation (EFS) and alpha-adrenergic agonist were studied in mesenteric resistance arteries from SHR and Wistar Kyoto rats. SHR were treated for 16 weeks with vehicle, pyridostigmine (1.5 mg/kg/day) or donepezil (1.4 mg/kg/day).
RESULTS
Pyridostigmine and donepezil decreased the vasoconstrictor responses to EFS, which were increased in vehicle-treated SHR. Acetylcholinesterase inhibition increased the modulatory effects of nitric oxide (NO) on SHR vascular reactivity, that is, N(ω)-nitro-(L)-arginine methyl ester (L-NAME) increased EFS-induced contractions and reduced ACh-induced relaxation, with more significant effects in pyridostigmine- and donepezil-treated SHR. The acetylcholinesterase inhibitors also decreased vascular reactive oxygen species levels.
CONCLUSIONS
This study demonstrates for the first time that long-term administration of acetylcholinesterase inhibitors, pyridostigmine or donepezil, attenuates vascular reactivity dysfunction in SHR by decreasing reactive oxygen species generation and increasing NO bioavailability; possibly via increased endothelial NO synthase activity, and inhibition of NADPH oxidase activity.
Topics: Acetylcholinesterase; Animals; Antihypertensive Agents; Arterial Pressure; Cholinesterase Inhibitors; Disease Models, Animal; Donepezil; GPI-Linked Proteins; Hemodynamics; Hypertension; Mesenteric Arteries; NADPH Oxidases; Nitric Oxide; Nitric Oxide Synthase Type III; Pyridostigmine Bromide; Rats, Inbred SHR; Rats, Inbred WKY; Reactive Oxygen Species; Vascular Resistance; Vasoconstriction; Vasodilation
PubMed: 30875426
DOI: 10.1093/ajh/hpz036 -
Case Reports in Neurology 2021It remains uncertain to what extent lower urinary tract (LUT) symptom (LUTS) is a comorbidity of myasthenia gravis (MG). We prospectively administered a LUTS...
It remains uncertain to what extent lower urinary tract (LUT) symptom (LUTS) is a comorbidity of myasthenia gravis (MG). We prospectively administered a LUTS questionnaire devised for detecting neurogenic pelvic organ dysfunction (not validated) in an MG group and a healthy control group and compared the results. The MG group comprised 21 patients: 15 women and 6 men, with age range 22-73 (mean 47) years, illness duration range 0.2-8 (mean 3.5) years, median Myasthenia Gravis Foundation of America (MGFA) grade 2, all walking independently. Therapies included thymectomy in 17, predonisolone 5-20 mg/day in 10, and pyridostigmine bromide 60-180 mg/day in 9 patients. The control group, who were undergoing an annual health survey, comprised 235 consecutive subjects: 120 women and 115 men, with age range 30-69 (mean 48) years. The questionnaire had 9 questions. Each question was scored from 0 (none) to 3 (severe) with an additional quality of life (QOL) index scored from 0 (satisfied) to 3 (extremely dissatisfied). Statistical analysis was made using Student's test. Compared with the control subjects, the frequency of LUTSs in the MG patients was significantly higher for daytime frequency (43%; < 0.01), nocturia (24%; < 0.01), and urinary incontinence (43%; < 0.05). The LUTS-related QOL index for the MG patients was significantly higher for MG patients as a whole than that for all control patients (29%) ( < 0.05). In conclusion, our study results showed that MG patients had significantly more LUTSs (overactive bladder) than healthy control subjects and had worse LUTS-related QOL; therefore, amelioration of LUTS in MG is important.
PubMed: 34413752
DOI: 10.1159/000514825