Myasthenia gravis is one of the typical organ specific autoimmune disease and the CD5+ B-lymphocytes are known to be associated with the secretion of autoimmune antibodies. The authors performed the study to establish an animal model of experimental autoimmune myasthenia gravis (EAMG) by immunizing the nicotinic acetylcholine receptor (AChR) and to understand CD5+ B-lymphocyte changes in peripheral blood of EAMGs. Lewis rats weighing 150-200 g were injected subcutaneously three times with 50 microg AChR purified from the electric organ of Torpedo marmorata and Freund's adjuvant. The EAMG induction was assessed by evaluating clinical manifestations. The CD5+ B-lymphocyte was double stained using monoclonal PE conjugated anti-CD5+ and FITC conjugated anti-rat CD45R antibodies and calculated using a fluorescence-activated cell sorter (FACS). In three out of ten Lewis rats injected with purified AChR, the EAMG models were established. The animals showed definite clinical weakness responded to neostigmine; they had difficulty in climbing the slope, or easily fell down from a vertical cage. The range of CD5+ B-lymphocytes of peripheral blood in the EAMG models was 10.2%-17.5%, which was higher than in controls. In conclusion, the EAMG models were successfully established and the CD5+ B-lymphocyte expression in peripheral blood increased in EAMGs. This provided indirect evidence of the autoimmune pathomechanism of human myasthenia gravis.
Animal ; Antigens, CD5/immunology* ; B-Lymphocytes/immunology* ; Disease Models, Animal ; Myasthenia Gravis/immunology* ; Myasthenia Gravis/chemically induced ; Rats ; Rats, Inbred Lew

OBJECTIVETo study the neuromuscular function and its relation with the occurrence of myasthenia in rats poisoned by dimethoate (D), phoxim (P), methomyl (M), M + D and M + P respectively.

METHODSThe stimulation single fiber electromyography(SSFEMG) at different stimulus frequencies(5, 10 and 20 Hz) was used. The whole blood cholinesterase (ChE) activity was measured 1 h before and after poisoning.

RESULTS(1) Myasthenia occurred in 5 out of 9.5 out of 10.5 out of 5, and 8 rats poisoned by D, P, M + D, and M + P, respectively. (2) The average mean consecutive differences(MCD) at 5, 10, and 20 Hz in myasthenic rats were significantly higher than those of poisoned rats without myasthenia and the control ones. (3) SSFEMG changes at 5, 10 and 20 Hz were significantly consistent with the clinical manifestation of myasthenia, especially at 10 Hz and 20 Hz. (4) ChE activity was significantly lower in rats with P or D poisoning while ChE inhibition was of no difference in rats with M, M + D, and M + P poisoning. In the D poisoning and P poisoning groups, there was no significant difference in ChE inhibition between the rats with and without myasthenia.

CONCLUSIONMuscle weakness was associated with neuromuscular transmission dysfunction, but not well correlated with ChE inhibition. The SSFEMG with stimulus frequency at 10 Hz or 20 Hz could be used to detect the neuromuscular dysfunction during myasthenia induced by organophosphate insecticides and their mixtures poisoning.

Animals ; Cholinesterase Inhibitors ; poisoning ; Dimethoate ; poisoning ; Electromyography ; Insecticides ; poisoning ; Methomyl ; poisoning ; Muscle Weakness ; chemically induced ; Myasthenia Gravis ; chemically induced ; physiopathology ; Neuromuscular Junction ; drug effects ; physiology ; Organothiophosphorus Compounds ; poisoning ; Rats ; Synaptic Transmission ; drug effects

PURPOSE: To compare the clinical manifestations between patients with ocular myasthenia gravis and those with generalized myasthenia gravis (MG). METHODS: The medical records of 71 patients diagnosed with MG between January 1995 and December 2007 were reviewed. Demographics, sensitivities of diagnostic methods, the presence of systemic autoimmune diseases, ophthalmic complications caused by MG, and treatments were evaluated and compared. RESULTS: Fourteen patients (20%) were diagnosed with ocular MG and 57 patients (80%) with generalized MG. Sensitivities of anti-acetylcholine receptor antibody and repetitive nerve stimulation tests were significantly higher in the generalized MG group (84%, 89%) compared to those in the ocular MG group (50%, 54%) (p = 0.011, p = 0.008). The sensitivity of the neostigmine test was the highest in both groups (98% of generalized MG, 79% of ocular MG), and the difference between the two groups was borderline significant (p = 0.058). The most common symptoms were ptosis and diplopia, and both groups presented with pain, blurred vision, and tearing. Systemic autoimmune disease was more prominent in the generalized MG group (21%) than in the ocular MG group (14%), and steroid therapy was used more frequently in the generalized MG group (82%) than in the ocular MG group (57%). Ophthalmic complications associated with long-term steroid treatment were more profound in the generalized MG (30%) compared to those of the ocular MG (21%). CONCLUSIONS: The generalized MG group was associated with higher sensitivities to diagnostic tests, more systemic steroid use, higher ophthalmic complications caused by systemic autoimmune disease, and long-term steroid treatment compared to those of the ocular MG group.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Autoimmune Diseases/complications ; Child ; Drug Administration Schedule ; Eye Diseases/chemically induced/immunology ; Female ; Humans ; Male ; Middle Aged ; Myasthenia Gravis/complications/*diagnosis/*drug therapy ; Steroids/*administration & dosage/adverse effects ; Young Adult

OBJECTIVETo explore the potential biochemical mechanisms of neuromuscular junction transmission (NMJT) dysfunction induced by organophosphorus insecticides.

METHODSTen rats were dosed with phoxim (1,144 mg/kg) and 5 of them developed myasthenia. The NMJT function was evaluated by the mean consecutive differences (MCD) measured by stimulation single fiber electromyography (SSFEMG) with the frequency of stimuli at 20 Hz. The activity of Ca(2+)-ATPase, Na(+), K(+)-ATPase, cAMP dependent protein kinase (PKA), Ca(2+)/phospholipid dependent protein kinase (PKC), and tyrosine protein kinase (TPK) were determined.

RESULTSIn comparison with the control and non-myasthenic rats, the results in myasthenic rats showed that: (1) the MCDs increased; (2) the activities of Ca(2+)-ATPase, Na(+), K(+)-ATPase and PKA decreased and were negatively correlated with MCD; (3) the activities of PKC and TPK increased, and were positively correlated with MCD; (4) the phosphorylation of serine residuals in sarcolemma was weaker and the phosphorylation of tyrosine residuals was stronger.

CONCLUSIONSThe NMJT dysfunction is likely associated with the decrease in Ca(2+)-ATPase and Na(+), K(+)-ATPase activity. The acceleration of desensitization and prolongation of resensitization of nicotinic acetylcholine receptors occur following the increase in tyrosine phosphorylation and the decrease in serine phosphorylation induced by OPs poisoning.

Animals ; Calcium-Transporting ATPases ; metabolism ; Cyclic AMP-Dependent Protein Kinases ; Electromyography ; drug effects ; Insecticides ; pharmacokinetics ; toxicity ; Myasthenia Gravis ; chemically induced ; enzymology ; Organothiophosphorus Compounds ; pharmacokinetics ; toxicity ; Protein Kinase C ; metabolism ; Protein-Serine-Threonine Kinases ; metabolism ; Rats

OBJECTIVETo explore the association of gene polymorphism of organophosphate insecticides (OPs) metabolic enzymes with intermediate myasthenia syndrome (IMS) following acute OPs poisoning.

METHODSThirty six of 147 acute OPs poisoning patients developed IMS one to four days after poisoning. Peripheral blood samples were collected from all the patients and whole blood cholinesterase (ChE) activity was determined by DTNB spectrometry. The genetic polymorphism of CYP2E1 (1091C-->T) and GSTP1 (313A-->G) were analyzed by polymerase chain reaction (PCR)-restrict fragment length polymorphism, CYP1A1 (4889A-->G), GSTM1 and GSTT1 by allele-specific PCR, and PON1 at 55 codon (55L-->M) by PCR-single strand conformation polymorphism.

RESULTSThe whole blood ChE activity in IMS patients was not significantly different from non-IMS patients at admission (38.22 +/- 17.56)% and (42.49 +/- 16.23)%, respectively, P > 0.05, but recovered much slower in IMS patients than that in non-IMS patients. The frequencies of heterozygote and variant homozygote of PON1 at 55 codon, GSTM1 null, and both GSTM1 and GSTT1 null were higher in IMS patients than those in non-IMS patients (P < 0.05), with odds ratios and their 95% confident intervals of 2.48 (1.06 - 5.78), 11.23 (2.95- 42.76), 2.53 (1.14 - 5.61) and 2.68 (1.20 - 5.97), respectively.

CONCLUSIONSPatients of OPs and its mixture poisoning with genotype of variant allele at 55 codon of PON1, GSTM1 null and both GSTM1 and GSTT1 null probably had higher risk for IMS.

Adult ; Cholinesterases ; metabolism ; Cytochrome P-450 CYP2E1 ; genetics ; Female ; Genetic Predisposition to Disease ; Genotype ; Glutathione Transferase ; genetics ; Homozygote ; Humans ; Insecticides ; poisoning ; Male ; Middle Aged ; Myasthenia Gravis ; chemically induced ; genetics ; Organophosphorus Compounds ; Point Mutation ; Polymorphism, Restriction Fragment Length ; Polymorphism, Single Nucleotide ; Syndrome

A 63-year-old male experienced sudden diplopia after 9 weeks of administration of pegylated interferon (IFN) alpha-2b and ribavirin for chronic hepatitis C (CHC). Ophthalmologic examinations showed ptosis on the right upper lid and restricted right eye movement without any other neurological signs. A brain imaging study and repetitive nerve stimulation test indicated no abnormality. The acetylcholine receptor antibody titer and response to acetylcholinesterase inhibitors were negative, and the results of thyroid function tests were normal. The patient's ophthalmological symptoms improved rapidly 3 weeks after discontinuation of pegylated IFN alpha-2b and ribavirin. The ocular myasthenia associated with combination therapy of pegylated IFN alpha-2b and ribavirin for CHC is very rarely reported; therefore, we present this case with a review of the various eye complications of IFN therapy.
Antiviral Agents/*adverse effects/therapeutic use ; Drug Therapy, Combination ; Hepatitis C, Chronic/complications/*drug therapy ; Humans ; Interferon Alfa-2b/*adverse effects/therapeutic use ; Male ; Middle Aged ; Myasthenia Gravis/*chemically induced/*diagnosis ; Polyethylene Glycols/*adverse effects/therapeutic use ; Ribavirin/*adverse effects/therapeutic use