Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0684249 (lung carcinoma)
 23,830 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The clinical and electrophysiological data of 18 consecutive adult patients with paraneoplastic Lambert-Eaton myasthenic syndrome (LMES) have been reviewed. The cancer associated with LEMS was small-cell lung carcinoma (SCLC) in 15 cases and epidermoid lung carcinoma in 3 cases. The main clinical neurological features were proximal lower limb weakness (100%), depressed tendon reflexes (94%) and dryness of the mouth (66%). The results of repetitive nerve stimulation (RNS) were not statistically different in the paraneoplastic LEMS group and in a group of 6 LMS patients in whom no carcinoma had been detected. Low-amplitude compound muscle action potential (CMAP) was present in all cases; decremental response at low stimulation rates was present in 13/15 cases. An abnormal incremental response at high stimulation rates was observed in all cases. A close correlation between CMAP amplitude and clinical condition was found in 4 cases during the long-term follow-up. In one patient the RNS electrical pattern could be misinterpreted as myasthenia gravis in only one muscle tested. We underline the usefulness of a 50 Hz stimulation during 4 seconds to establish the diagnosis unequivocally, and that of post-exercise facilitation in routine detection among an SCLC population. Our results suggest that CAMP amplitude and RNS test could be used to evaluate the short-term improvement of LMS under treatment and, in some cases, for the long-term follow-up. The infraclinical axonal neuropathy detected in 8 patients probably was another associated autoimmune paraneoplastic complication.
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PMID:[Lambert-Eaton syndrome: clinical and electrophysiological study of 18 cases associated with lung cancer]. 144 71

The electrophysiological data of 23 adult patients with Lambert-Eaton myasthenic syndrome (LEMS) have been reviewed. Lung carcinoma was disclosed in 17. In six cases with an EMG follow-up ranging between one and 17 years no carcinoma was detected. The results of repetitive nerve stimulation test (RNS) were not statistically different between the 2 groups. Low CMAP ulnar amplitude was present in all patients (mean: 1.7 mV). Decremental response at low rate of stimulation (3 Hz) was present in 17/20 (means: 30%). An abnormal incremental response at high rate of stimulation was present in all cases (mean: 826%). The authors emphasize the interest of a 50 Hz stimulation for 4 s. Increase of the 'F-wave' amplitude was noticed in some cases. Electrophysiological changes suggestive of an associated mild neuropathy were noticed in eight patients but H-reflex was present in 3/3 cases. SFEMG abnormalities were found in 6/6 cases. In one case, stimulated SFEMG showed more blockings and an increased jitter with low rate of stimulation. In one case the electrical pattern of RNS could be misinterpreted as myasthenia gravis in one tested muscle only. The author's results suggest that CMAP amplitude and RNS test could be used to appreciate the short-term improvement of LEMS with treatment and in some cases for the long-term follow-up.
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PMID:[Electrophysiologic data on myasthenic syndromes of the Lambert-Eaton type. A series of 23 cases]. 158

The Lambert-Eaton myasthenic syndrome (LEMS) is a disorder of neuromuscular transmission, often associated with small cell lung carcinoma (SCLC), and characterized by reduced quantal release of acetylcholine from the motor nerve terminals. Another neuromuscular transmission disorder, myasthenia gravis, has a well-understood autoimmunological cause. This review discusses the evidence for a similar autoimmunological effect in the development of LEMS. Injection of LEMS IgG into mice passively transfers the physiological and morphological abnormalities, which include paucity and disorganized arrangement of active zone particles believed to represent the voltage-gated calcium channels (VGCCs). Calcium influx via VGCCs into SCLC cells is reduced by LEMS IgG suggesting that in SCLC-associated LEMS, antibodies may be triggered by VGCCs expressed on these cells; this immunological cross-reactivity may lead to the neurological abnormality. Similar VGCCs on neuronally derived cells may trigger the disorder in those without a tumour. The disorder provides another example of the complicated relationships between the nervous and immune systems and tumorigenic processes.
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PMID:Autoimmunity to the voltage-gated calcium channel underlies the Lambert-Eaton myasthenic syndrome, a paraneoplastic disorder. 248 Jun 64

Serum autoantibodies found by radioimmunoassay in 27 of 52 patients with the Lambert-Eaton myasthenic syndrome (LES) bound specifically to a soluble omega-conotoxin binding component of a voltage-gated Ca2+ channel (VGCC) complex extracted from small cell lung carcinoma (SCC). These antibodies were not found in 43 control patients with other neurologic diseases, including myasthenia gravis, peripheral neuropathies, and amyotrophic lateral sclerosis, or in 9 patients with endocrine autoimmunity, but they were found in 2 of 21 control patients with SCC without a history of LES, 1 of whom had severe autonomic neuropathy. Seropositivity was more frequent in patients with LES who had evidence of a primary lung cancer (76%) than in those with other neoplasms or without evidence of cancer (30%). Antigens extracted from SCC tumor lines derived from patients with and without LES and from a human neuroblastoma line yielded results that were highly correlated. A control extract of colonic carcinoma (derived from a patient with LES) yielded negative results. The data implicate a tumor-associated VGCC as the autoimmunizing stimulus in a subset of patients with LES and provide the first direct evidence that the VGCC complex in SCC is a target for some LES antibodies. The serologic test described should be a useful aid in diagnosing LES.
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PMID:Autoantibodies bind solubilized calcium channel-omega-conotoxin complexes from small cell lung carcinoma: a diagnostic aid for Lambert-Eaton myasthenic syndrome. 255 95

A 56-year-old man had been complaining of progressive proximal muscle weakness and bilateral ptosis before his first admission to our hospital. He received an injection of edrophonium chloride, which resulted in remarkable improvement of muscle strength. Electromyographic studies revealed a compound muscle action potential that decreased after repetitive stimulation at a high rate (15 Hz). He was regarded as having myasthenia gravis (MG) rather than Eaton-Lambert syndrome because of these findings. Eighteen months after successful treatment of MG with oral anticholinesterase medication, he complained of an abdominal mass. The mass was found to be a tumor that had metastasized from a primary small cell carcinoma of the lung. Cases of MG with small cell carcinoma of the lung seem to be very rare, and the details of the relationship between them remain unknown. In this patient, MG may have developed by paraneoplastic mechanisms. This hypothesis is interesting, since it has been demonstrated recently by molecular biological techniques that small cell carcinomas of the lung express nicotinic acetylcholine receptors.
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PMID:[A case of small cell lung cancer that developed during therapy for myasthenia gravis]. 779 Dec 77

A 49-year-old man complained of a 3-month history of progressive generalized muscle weakness. He was diagnosed as having small-cell lung carcinoma at the same time. He received an intravenous injection of edrophonium chloride with remarkable improvement of muscle strength. Electromyographic studies revealed a compound muscle action potential that decreased after repetitive stimulation. These findings were considered representative of myasthenia gravis (MG), and inconsistent with Eaton-Lambert syndrome. The appearance of MG with small-cell lung carcinoma seems to be very rare, but possible.
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PMID:Myasthenia gravis associated with small-cell carcinoma of the lung. 830 83

Barium currents through voltage-gated calcium (Ca2+) channels were studied in the small-cell lung carcinoma cell line NCI-H345 using patch clamp techniques. Pharmacological dissection of whole-cell barium currents revealed that 23% of the current was sensitive to nitrendipine, 35% to omega-conotoxin GVIA, and between 10 and 39% to omega-Aga-IVA. This implies that these cells express L-, N-, and P-type calcium channels. Only large cells expressed current that was sensitive to omega-Aga-IVA. The size dependency of this P-type channel expression may reflect the cell cycle stage. Cell-attached recordings revealed three unitary conductances: 5 to 6 pS, 10 to 12 pS, and 20 to 23 pS. The largest conductance channel (20-23 pS) was sensitive to Bay K 8644 and is presumed to represent L-type calcium channels. The frequency of observing the medium conductance channel (10-12 pS) was reduced by exposure to omega-conotoxin GVIA and may represent N-type channels. Incubation of cells with Lambert-Eaton myasthenic syndrome IgG for 24 to 48 hours removed up to 71% of the whole-cell current. Incubation with control human IgG (normal or myasthenia gravis) had no effect. Lambert-Eaton myasthenic syndrome IgG did not selectively target one "presynaptic" type of calcium channel, but rather appeared to target many of the calcium channel types that are expressed on small-cell lung carcinoma cells.
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PMID:Lambert-Eaton myasthenic syndrome immunoglobulins react with multiple types of calcium channels in small-cell lung carcinoma. 895 15

To search for antigenic sites in the molecular structure of alpha1A subunit of the voltage-gated calcium channel (VGCC) (P/Q-type) in the Lambert-Eaton myasthenic syndrome (LEMS), we studied by immunoprecipitation assay serum samples from 30 LEMS patients (16 with small cell lung carcinoma (SCLC), 20 disease controls (10 with SCLC without LEMS and 10 with myasthenia gravis), and 15 healthy controls. Synthetic peptide antigens corresponded to the extracellular region (S5-S6 linker region) of each of the four domains forming the alpha1 subunit of P/Q-type VGCC. In addition, we studied serum samples for anti-P/Q-type VGCC antibodies by using omega-conotoxin MVIIC-labeled extract of human cerebellum as an antigen. Among sera of 30 LEMS patients, nine samples (30%) (six with SCLC) were positive for antibodies to the domain IV S5-S6 linker peptide, and six samples (20%) (five with SCLC) were positive for antibodies to the domain II S5-S6 linker peptide. Only two of 15 antipeptide-positive sera were positive for both antibodies. Titers for antibodies to domain IV, as well as those for antibodies to domain II, correlated with those of anti-P/Q-type VGCC (human cerebellum extract) antibodies. The antipeptide antibody was present in only one of 20 disease controls, a patient with SCLC without LEMS. Our observations suggest two potential epitopes of LEMS antibodies.
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PMID:Antibodies to synthetic peptides of the alpha1A subunit of the voltage-gated calcium channel in Lambert-Eaton myasthenic syndrome. 915 53

SCC-37 is a small cell lung carcinoma line that aberrantly expresses muscle-type nicotinic acetylcholine receptors (nAChRs). It was established from a patient with a paraneoplastic autoimmune neuromuscular disorder, myasthenia gravis. When grown as a xenograft tumor, SCC-37 cells express plasma membrane receptors that bind 1251-labeled alpha-bungarotoxin (125I-alpha-BTx), cosediment with 9S nAChR pentamers, and bind to a monoclonal antibody (MAb 35) specific for muscle-type (alpha1 subunit) alpha-BTx receptors. The agonist carbamylcholine (carbachol) stimulates influx of 22Na+ in SCC-37 cells; this is inhibited by alpha-BTx and by d-tubocurarine. Long-term cultured SCC-37 cells have functional and ligand-binding evidence for surface coexpression of both alpha1 and neuronal-type (alpha7 subunit) alpha-BTx receptors. A subclone of SCC-37, designated SCC-A9, expresses only the neuronal-type (alpha7 subunit) alpha-BTx receptors on its surface. Carbachol does not stimulate 22Na+ influx in SCC-A9 cells, but cytisine initiates a sustained influx of Ca2+. Activation of this response is inhibited by alpha-BTx and by the alpha7-selective antagonist methyllycaconitine. Addition of Co2+ abrogates the sustained elevation of intracellular free Ca2+ concentration, implying that the cytisine-stimulated influx of Ca2+ is sustained by secondary opening of voltage-sensitive channels in the plasma membrane. Surface receptors for 125I-alpha-BTx are blocked by methyllycaconitine and d-tubocurarine. Solubilized alpha-BTx receptors from plasma membranes of SCC-A9 cells cosediment with 10S neuronal nAChR pentamers and bind to an alpha7-specific monoclonal antibody (MAb P27) but not to the muscle nAChR-reactive MAb 35. However, MAb P27 and MAb 35 both bind to alpha-BTx receptors solubilized from the cytoplasmic compartments of SCC-A9 and the parental SCC-37 line. Reverse transcription-PCR analysis revealed RNA transcripts for alpha7 and alpha1 subunits in both SCC-A9 and SCC-37 cells. The nAChRs that are expressed in these novel human cell lines can regulate cation fluxes directly as well as indirectly by synergizing with the activity of voltage-sensitive Ca2+ channels. These activities may influence the secretion of autocrine growth factors and the transcription of growth regulatory genes and thus be pertinent to the growth and metastasis of malignant neuroendocrine neoplasms.
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PMID:Nicotinic acetylcholine receptors of muscle and neuronal (alpha7) types coexpressed in a small cell lung carcinoma. 937 61

The ectopic expression of neuronal P/Q-type voltage-gated calcium channels in small cell lung carcinoma (SCLC) is thought to induce antisynaptic autoimmunity in the paraneoplastic Lambert-Eaton myasthenic syndrome. The gene CACNL1A4, encoding the principal (alpha1A) subunit of this calcium channel, is mutated in several inherited neurological disorders. One of these disorders (spinocerebellar ataxia, type 6, or SCA-6) involves the expansion of a trinucleotide (CAG) repeat unit. We hypothesized that a somatic CAG repeat instability of this gene in neoplastic cells might generate a non-self epitope capable of initiating autoimmunity to P/Q-type calcium channels. We therefore analyzed the CACNL1A4 gene in SCLC lines established from metastases derived from seven individual patients (four associated with Lambert-Eaton myasthenic syndrome, one associated with myasthenia gravis, and two not associated with neurological autoimmunity). We compared their CAG repeat numbers (determined by polymerase chain reaction (PCR) amplification followed by separation of products on a 6% polyacrylamide/8M urea gel) to published norms and to DNA from a patient with SCA-6. The number of CAG repeats in SCLC DNA fell within a normal range whether or not the neoplasm was complicated by neurological autoimmunity. Therefore, it is unlikely that somatically unstable CAG repeat units in the gene encoding the P/Q-type voltage-gated calcium channel account for this tumor protein's immunogenicity in the Lambert-Eaton myasthenic syndrome.
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PMID:Immunogenicity of P/Q-type calcium channel in small cell lung cancer: investigation of alpha1 subunit polyglutamine expansion. 1067 74


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