- Congenital myasthenic syndrome due to rapsyn deficiency: A case report with a new mutation and compound heterozygosity. [Case Reports]
- MMedwave 2019 Jun 04; 19(5):e7645
- CONCLUSIONS: Weakness and fatigability with neonatal onset, mainly affecting the muscles with brain stem innervation and the decrement greater than 10 percent in the Compound Muscular Action Potential in the electromyographic studies, should make us suspect in a congenital myasthenic syndrome. We review the literature and key clinical points to establish a timely diagnosis and effective treatment in some of these syndromes.
- Pyridostigmine regulates glucose metabolism and mitochondrial homeostasis to reduce myocardial vulnerability to injury in diabetic mice. [Journal Article]
- AJAm J Physiol Endocrinol Metab 2019 Jun 18
- 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,…
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 GLUT1/4, PFKFB3 and PKM was decreased in diabetic mice, but increased in isoproterenol-stimulated normal mice. Following exposure to isoproterenol, the expression of GLUT1/4, PFKFB3 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, 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.
- Green Simultaneous Chromatographic Separation of Pyridostigmine Bromide and Its Related Substances in Pure Form, Tablets and Spiked Human Plasma. [Journal Article]
- JCJ Chromatogr Sci 2019 Jun 14
- A green, accurate and specific high-performance thin-layer chromatographic (HPTLC) method was developed and validated for simultaneous quantitative determination of pyridostigmine bromide (PR), impur…
A green, accurate and specific high-performance thin-layer chromatographic (HPTLC) method was developed and validated for simultaneous quantitative determination of pyridostigmine bromide (PR), impurity B (IMP B);3-hydroxy-N-methylpyridinium bromide and impurity A (IMP A); pyridin-3-yl-dimethylcarbamate. The two pharmacopeial impurities are also its main inactive metabolites. Furthermore, IMP B is known to be its alkaline-induced degradation product. Achievable separation of the studied components required silica gel HPTLC F254 plates as a stationary phase and acetone: acetic acid (80:20, v/v) as a developing system. Scanning of the separated bands was done at 260 nm. According to green solvent selection guidelines, acetone and acetic acid are eco-friendly solvents. Validation of the developed method was insured by its acquiesce to international conference on harmonization (ICH) guidelines. The introduced method was successfully achieved for the quantitative determination of PR, IMP B and IMP A in the range of 0.4-10, 2-11 and 0.4-3.5 μg/band, respectively. Successful application of the developed method was done for determination of PR in human plasma in the range of 0.6-10 μg/band, so the proposed HPTLC can be applied in the pharmacokinetic studies. The studied drug was also analyzed in Mestinon® tablets using the developed method.
- The Experimental Oxime K027-A Promising Protector From Organophosphate Pesticide Poisoning. A Review Comparing K027, K048, Pralidoxime, and Obidoxime. [Review]
- FNFront Neurosci 2019; 13:427
- Poisoning with organophosphorus compounds (OPCs) is a major problem worldwide. Standard therapy with atropine and established oxime-type enzyme reactivators (pralidoxime, obidoxime) is unsatisfactory…
Poisoning with organophosphorus compounds (OPCs) is a major problem worldwide. Standard therapy with atropine and established oxime-type enzyme reactivators (pralidoxime, obidoxime) is unsatisfactory. In search of more efficacious broad-spectrum oximes, new bispyridinium (K-) oximes have been synthesized, with K027 being among the most promising. This review summarizes pharmacokinetic characteristics of K027, its toxicity and in vivo efficacy to protect from OPC toxicity and compares this oxime with another experimental bisquaternary asymmetric pyridinium aldoxime (K048) and two established oximes (pralidoxime, obidoxime). After intramuscular (i.m.) injection, K027 reaches maximum plasma concentration within ∼30 min; only ∼2% enter the brain. Its intrinsic cholinesterase inhibitory activity is low, making it relatively non-toxic. In vitro reactivation potency is high for ethyl-paraoxon-, methyl-paraoxon-, dichlorvos-, diisopropylfluorophosphate (DFP)- and tabun-inhibited cholinesterase. When administered in vivo after exposure to the same OPCs, K027 is comparable or more efficacious than pralidoxime and obidoxime. When given as a pretreatment before exposure to ethyl-paraoxon, methyl-paraoxon, DFP, or azinphos-methyl, it is superior to the Food and Drug Administration-approved compound pyridostigmine and comparable to physostigmine, which because of its entry into the brain may cause unwanted behavioral effects. Because of its low toxicity, K027 can be given in high dosages, making it a very efficacious oxime not only for postexposure treatment but also for prophylactic administration, especially when brain penetration is undesirable.
- The Val16Ala-SOD2 polymorphism affects cyto-genotoxicity of pyridostigmine bromide on human peripheral blood mononuclear cells. [Journal Article]
- TVToxicol In Vitro 2019 Jun 06; 60:237-244
- Pyridostigmine bromide (PB), an acetylcholinesterase (AChE) enzyme inhibitor. Experimental evidence showed that when combined with other drugs or exercise, PB caused extensive neural and/or systemic …
Pyridostigmine bromide (PB), an acetylcholinesterase (AChE) enzyme inhibitor. Experimental evidence showed that when combined with other drugs or exercise, PB caused extensive neural and/or systemic oxidative stress. However, no studies have been conducted on the genetic influence associated with basal oxidative superoxide-hydrogen peroxide (S-HP) imbalance, such as that triggered by Val16Ala-SOD2 single nucleotide polymorphism (SNP, rs4880). This SNP, (homozygous genotypes) has been associated with several chronic degenerative disorders. Therefore, we evaluated whether the SOD-SNP could alter cyto-genotoxic effects triggered by different PB-concentrations in peripheral blood mononuclear cells (PBMCs). PBMCs were obtained from volunteers carrying different SOD2-genotypes and were cultured with various concentrations of PB. PB effects in quantity of enzyme AChE, mortality rate, oxidative stress markers, and DNA damage were assessed. Protein and gene expression of antioxidant enzymes, apoptotic markers and DNA repair enzyme, were evaluated in 24 h cultures. In general, PB up-regulated expression of antioxidant enzymes, and did not trigger apoptotic events. However, AA-PBMCs seemed more sensitive to PB exposure, in a protein decrease of the enzyme AChE by 10%, cell-mortality at concentrations of 20 and 40 ng/mL, protein carbonylation, and DNA damage, as analyzed by the Comet assay. Contrarily, PB demonstrated cyto-genoprotective effects on V-allele cells. These results indicated that genetic factors that increase HP-release may affect PB efficiency and safety.
- Immunomodulatory role of non-neuronal cholinergic signaling in myocardial injury. [Journal Article]
- JIJCI Insight 2019 Jun 04; 5
- Whereas prior studies have demonstrated an important immunomodulatory role for the neuronal cholinergic system in the heart, the role of the non-neuronal cholinergic system is not well understood. To…
Whereas prior studies have demonstrated an important immunomodulatory role for the neuronal cholinergic system in the heart, the role of the non-neuronal cholinergic system is not well understood. To address the immunomodulatory role of the non-neuronal cholinergic system in the heart we used a previously validated diphtheria toxin (DT)-induced cardiomyocyte ablation model (Rosa26-DTMlc2v-Cre mice). DT-injected Rosa26-DTMlc2v-Cre mice were treated with diluent or Pyridostigmine Bromide (PYR), a reversible cholinesterase inhibitor. PYR treatment resulted in increased survival and decreased numbers of MHC-IIlowCCR2+ macrophages in DT-injected Rosa26-DTMlc2v-Cre mice compared to diluent treated Rosa26-DTMlc2v-Cre mice. Importantly, the expression of CCL2/7 mRNA and protein was reduced in the hearts of PYR-treated mice. Backcrossing Rosa26-DTMlc2v-Cre mice with a transgenic mouse line (Chat-ChR2) that constitutively overexpresses the vesicular acetylcholine transporter (VAChT) resulted in decreased expression of Ccl2/7 mRNA and decreased numbers of CD68+ cells in DT-injured Rosa26-DTMlc2v-Cre/Chat-ChR2 mouse hearts, consistent with the pharmacologic studies with PYR. In vitro studies with cultures of LPS-stimulated peritoneal macrophages revealed a concentration-dependent reduction in CCL2 secretion following stimulation with ACh, nicotine and muscarine. Viewed together, these findings reveal a previously unappreciated immunomodulatory role for the non-neuronal cholinergic system in regulating homeostatic responses in the heart following tissue injury.
- Metastatic Merkel cell carcinoma and myasthenia gravis: contraindication for therapy with immune checkpoint inhibitors? [Journal Article]
- JIJ Immunother Cancer 2019 May 29; 7(1):141
- CONCLUSIONS: Patients with a preexisting MG can be considered for treatment with immune checkpoint inhibitors if they have a life-threatening cancer and if other effective, long-lasting treatment options are not available. The risks and benefits of therapy should be weighed in a multidisciplinary setting and should be discussed thoroughly with the patient. Exacerbation of underlying MG can be potentially life-threatening and requires close monitoring in collaboration with neuromuscular specialists.
- The effect of pyridostigmine on small intestinal bacterial overgrowth (SIBO) and plasma inflammatory biomarkers in HIV-associated autonomic neuropathies. [Journal Article]
- JNJ Neurovirol 2019 May 16
- Small intestinal bacterial overgrowth (SIBO) is common among patients with HIV-associated autonomic neuropathies (HIV-AN) and may be associated with increased bacterial translocation and elevated pla…
Small intestinal bacterial overgrowth (SIBO) is common among patients with HIV-associated autonomic neuropathies (HIV-AN) and may be associated with increased bacterial translocation and elevated plasma inflammatory biomarkers. Pyridostigmine is an acetylcholinesterase inhibitor which has been used to augment autonomic signaling. We sought preliminary evidence as to whether pyridostigmine could improve proximal gastrointestinal motility, reduce SIBO, reduce plasma sCD14 (a marker of macrophage activation and indirect measure of translocation), and reduce the inflammatory cytokines IL-6 and TNFα in patients with HIV-AN. Fifteen participants with well-controlled HIV, HIV-AN, and SIBO were treated with 8 weeks of pyridostigmine (30 mg PO TID). Glucose breath testing for SIBO, gastric emptying studies (GES) to assess motility, plasma sCD14, IL-6, and TNFα, and gastrointestinal autonomic symptoms were compared before and after treatment. Thirteen participants (87%) experienced an improvement in SIBO following pyridostigmine treatment; with an average improvement of 50% (p = 0.016). There was no change in gastrointestinal motility; however, only two participants met GES criteria for gastroparesis at baseline. TNFα and sCD14 levels declined by 12% (p = 0.004) and 19% (p = 0.015), respectively; there was no significant change in IL-6 or gastrointestinal symptoms. Pyridostigmine may ameliorate SIBO and reduce levels of sCD14 and TNFα in patients with HIV-AN. Larger placebo-controlled studies are needed to definitively delineate how HIV-AN affects gastrointestinal motility, SIBO, and systemic inflammation in HIV, and whether treatment improves clinical outcomes.
- TSPO PET Using [18F]PBR111 Reveals Persistent Neuroinflammation Following Acute Diisopropylfluorophosphate Intoxication in the Rat. [Journal Article]
- TSToxicol Sci 2019 Apr 17
- Acute intoxication with organophosphates (OPs) can trigger status epilepticus followed by persistent cognitive impairment and/or electroencephalographic abnormalities. Neuroinflammation is widely pos…
Acute intoxication with organophosphates (OPs) can trigger status epilepticus followed by persistent cognitive impairment and/or electroencephalographic abnormalities. Neuroinflammation is widely posited to influence these persistent neurological consequences. However, testing this hypothesis has been challenging, in part because traditional biometrics preclude longitudinal measures of neuroinflammation within the same animal. Therefore, we evaluated the performance of non-invasive positron emission tomography (PET), using the translocator protein (TSPO) radioligand [18F]PBR111 against classic histopathologic measures of neuroinflammation in a preclinical model of acute intoxication with the OP diisopropylfluorophosphate (DFP). Adult male Sprague Dawley rats administered pyridostigmine bromide (0.1 mg/kg, im) 30 min prior to administration of DFP (4 mg/kg, sc), atropine sulfate (2 mg/kg, im) and 2-pralidoxime (25 mg/kg, im) exhibited moderate-to-severe seizure behavior. TSPO PET performed prior to DFP exposure and at 3, 7, 14, 21 and 28 days post-exposure (DPE) revealed distinct lesions, as defined by increased standardized uptake values (SUV). Increased SUV showed high spatial correspondence to immunohistochemical evidence of neuroinflammation, which was corroborated by cytokine gene and protein expression. Regional SUV metrics varied spatiotemporally with DPE and correlated with the degree of neuroinflammation detected immunohistochemically. Furthermore, SUV metrics were highly correlated with seizure severity, suggesting that early termination of OP-induced seizures may be critical for attenuating subsequent neuroinflammatory responses. Normalization of SUV values to a cerebellar reference region improved correlations to all outcome measures and seizure severity. Collectively, these results establish TSPO PET using [18F]PBR111 as a robust, non-invasive tool for longitudinal monitoring of neuroinflammation following acute OP intoxication.
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- Clinical and serologic remission of acquired myasthenia gravis in a domestic ferret (Mustela putorius furo). [Journal Article]
- JAJ Am Vet Med Assoc 2019 May 15; 254(10):1192-1195
- CONCLUSIONS: Findings indicated that clinical and serologic remission can be achieved in ferrets with myasthenia gravis. However, owner willingness to provide extensive supportive care was vital to the outcome for this patient, as was the owner's decision to not euthanize the ferret despite an initial lack of response to treatment.