Monoclonal antibody to acetylcholine receptor: cell line established from thymus of patient with Myasthenia gravis.

A human B cell line producing a monoclonal antibody to an antigenic determinant of acetylcholine receptors was established by cloning B cells that had been transformed in vitro by Epstein-Barr virus. The B cells were obtained from the thymus of a patient with myasthenia gravis. The antibody produced by the cell line precipitated acetylcholine receptors from denervated and innervated rat muscle and from human muscle, but did not show detectable response to the acetylcholine receptors from the electric organs of Narke japonica. The monoclonal antibody showed identical binding patterns in innervated and denervated rat muscles. Passive transfer of the monoclonal antibody into rats induced moderate muscle weakness and electromyographic changes characteristic of myasthenia gravis.

Ca content of human erythrocytes. What is the true value?

It has been generally accepted that the Ca content of washed erythrocytes is in the range of 1 - 3 X 10(-5) mole/l cells (1-10). These values were obtained after samples were treated in various way for Ca measurement. However, by using a simplified careful preparation technique to avoid Ca contamination together with inductively coupled argon plasma emission spectroscopy, we have found that the Ca content of erythrocytes washed with nominally Ca2+-free solution, is one order of magnitude lower than the reported values, in the range of 1 X 10(-6) moles/l cells.

Hemorrhage of thiamine-deficient encephalopathy.

Hemorrhagic lesions of pyrithiamine-induced acute thiamine-deficient encephalopathy of the mouse (PIATDEM) consisted of petechiae, which often coalesced to form small hematomas. Electron microscopy showed the typical petechial lesion to be composed of a perivascular necrotic zone containing fibrin-platelet clot surrounded by a ring of erythrocytes. Endothelial cells were intact and tight junctions were closed. A study of permeability to horseradish peroxidase (HRP) revealed only a slight increase in the number of transport vesicles in the endothelial cells. A large amount of HRP present in the lesions seemed to have entered the brain by a hemorrhagic route which remains unclarified. Spherical latex particles, 0.23 micrometer in diameter, were injected intravenously into encephalopathic mice at a time when intracerebral hemorrhages frequently occurred. Two to 24 hours after the injection, a large number of latex particles penetrated the blood vessels at sites of hemorrhage. There were many particles in the phagosomes of the endothelial cells, which suggested transendothelial transport by the organelle. The possibility of endothelial phagocytic transport of erythrocytes as a main route of diapedesis is discussed.

Low energy levels in thiamine-deficient encephalopathy.

Pyrithiamine-induced acute thiamine-deficient encephalopathy was produced in adult male Wistar rats. Twenty-four hours before the onset of neurological signs the brain showed no morphological abnormalities. Encephalopathic rats had symmetrical lesions of edematous necrosis localized in the thalamus, mammillary body, and pontine tegmentum. Biochemically, encephalopathic rats had brain thiamine levels less than 20% of controls. For the assay of the concentrations of adenosine triphosphate (ATP) and phosphocreatine, the brains were fixed using 5 KW microwave irradiation and were divided into four parts: cerebral cortex, diencephalon, lower brainstem, and cerebellum. In the lower brainstem of the encephalopathic rats ATP concentrations were 89.5% of normal controls. Phosphocreatine levels were lowered to 70% of controls in the diencephalon and to 75% in the lower brainstem. Total high energy phosphate levels were decreased to 89% of controls in the diencephalon and 91% in the lower brainstem before the onset of neurological signs and to 76% and 79%, respectively, after the onset. In the cerebral cortex and cerebellum high energy phosphates were not significantly reduced. Lower high energy phosphate levels and the distribution of edematous lesions were coincident in the brain. These findings suggest that a low energy state is closely related to the formation of edematous lesions in thiamine-deficient encephalopathy.

Aliphatic side chain of catecholamine potentiates the stimulatory effect of the catechol part on the synthesis of nerve growth factor.

Catecholamines are potent in stimulating nerve growth factor (NGF) synthesis in mouse L-M cells. The relationship between the structure of catecholamines and their stimulatory effect on NGF synthesis has been studied using various 3,4-dihydroxyphenyl derivatives or their analogues. All 3,4-dihydroxyphenyl derivatives with two saturated carbons on the side chain were potent stimulators, whereas those with only one carbon on the side chain were weak stimulators. Drugs lacking the catechol ring were not effective. These results suggest that the catechol part of catecholamines is essential for the stimulatory effect and that the aliphatic side chain potentiates this effect. The present results also suggest the terminal amino residue on the side chain is not critical for the effect.

Catecholamines increase nerve growth factor mRNA content in both mouse astroglial cells and fibroblast cells.

Previous studies have shown that catecholamines increase the nerve growth factor (NGF) content in medium conditioned by mouse L-M fibroblast cells and mouse astroglial cells. In this study, the NGF mRNA levels in these cells were measured by Northern blot analysis. In astroglial cells treated with epinephrine (EN), the cellular NGF mRNA level increased prior to accumulation of NGF in the culture medium. 3-Hydroxytyramine (DA) and norepinephrine (NE) also increased the cellular NGF mRNA content. An increased level of NGF mRNA elicited by EN was also observed in mouse L-M cells. These results indicate that catecholamines enhance NGF synthesis of L-M fibroblast cells and astroglial cells by increasing the cellular content of NGF mRNA. The present results also indicate that the effects of catecholamines are not mediated by adrenergic receptors.

Oculopharyngodistal myopathy.

An autosomal dominant, heredofamilial myopathy consisted of slowly progressive ptosis and extraocular palsy, and weakness of the masseter, facial, and bulbar muscles, as well as distal involvement of the limbs starting around 40 years of age or later. No other neurological symptoms or disturbances of other organs or tissues were observed. In one case, autopsy disclosed no remarkable change in the central and peripheral nervous system, and muscle biopsy specimens from all patients showed myopathic patterns without any specific change. A descriptive term, "oculopharyngodistal myopathy," was proposed to separate the present illness from other ocular myopathies.

Atypical myopathy with myofibrillar aggregates.

An autopsy of a 23-year-old woman with progressive muscular weakness and wasting showed a unique muscle abnormality with segmental involvement of individual fibers by peculiar inclusions. Electron microscopically, these inclusions resembled cytoplasmic bodies, being formed of two concentric zones of filamentous materials. They seemed to arise from filaments of myofibrils that were fragmented and highly disorganized in affected areas.

A syndrome of progressive muscle spasm, alopecia, and diarrhea.

A syndrome of progressive muscle spasm, alopecia, and diarrhea was seen in 15 patients. The syndrome was characterized by painful intermittent muscle spasm, alopecia, amenorrhea, and malabsorption, and was sometimes associated with epiphyseal destruction and retarded growth. Symptoms began at age 10 and were more common in women than men. Muscle cramps affected the limbs first and then, several years after onset, the neck, trunk, and masticatory muscles. The course was progressive and led to malnutrition. Four patients died from 5 to 18 years after onset. Autopsy revealed polypoid changes throughout the gastrointestinal tract.

Action-induced rhythmic dystonia: an autopsy case.

We studied a patient with action-induced rhythmic dystonia that followed a stroke. Postmortem studies showed an infarct in the right posterolateral ventral part of the thalamus. Electrophysiologic analysis indicated that the eliciting factor of the involuntary movement was an impulse, promoting voluntary contraction of muscle. CSF 5-HIAA content was low, and HVA was high. Administration of 5-HTP and clonazepam abolished the involuntary movements.

Idiopathic hyperCKemia.

In three adult men, serum creatine kinase activity was constantly raised for at least 4 years. They had been normal in other neuromuscular functions and did not have any established disease. Quantitative morphologic and pharmacologic studies were performed on biopsied muscle. The biceps brachii of patient 1 contained 0.3% necrotic fibers. In patient 2, only slight variation of muscle fiber diameter was noted. Muscle of patient 3 contained a few small angular fibers, and 11% of fibers exhibited internal nuclei. Sensitivity to caffeine in vitro was increased in patients 2 and 3, as seen in survivors of malignant hyperthermia; patients in hyperCKemia may be susceptible to malignant hyperthermia.

The Crow-Fukase syndrome: a study of 102 cases in Japan.

Clinical manifestations of 102 cases with the Crow- Fukase syndrome (the syndrome of polyneuropathy, anasarca, skin changes, endocrinopathy, dysglobulinemia, and organomegaly), with or without myeloma, were reviewed. Fifty-six cases with myeloma consisted of 31 with osteosclerotic, 17 with mixed osteosclerotic and osteolytic, and 8 with osteolytic. Forty-six cases without myeloma consisted of 2 with extramedullary plasmacytoma, 33 with M protein alone, and 11 with polyclonal protein alone. There was no significant difference in incidence of the major clinical manifestations between the two groups with and without myeloma. They had a common characteristic histologic finding of the lymph node resembling that of Castleman's disease.

An enzyme-linked immunosorbent assay for antibodies against saline-soluble muscle components in myasthenia gravis.

An enzyme-linked immunosorbent assay (ELISA) system has been developed for measuring antibodies against rat skeletal muscle components solubilized with phosphate-buffered saline. With this assay, 53.8% (50/93) of sera from patients with myasthenia gravis (MG) was positive (the values over the mean plus 3 SD of 256 healthy individuals were considered significant). No sera from patients with neurological disorders other than MG gave positive values (0%; 0/60). No correlation between titers of antibody against the muscle components and those of anti-acetylcholine receptor antibody (r = 0.01) was found. These results indicate that our ELISA system is useful for diagnosing myasthenia gravis.

Oculopharyngodistal myopathy is genetically heterogeneous and most cases are distinct from oculopharyngeal muscular dystrophy.

The question whether oculopharyngodistal myopathy (MIM 164310) is a distinct disease entity or a variant of oculopharyngeal muscular dystrophy (MIM 164300) persists. To answer this question, we examined five patients with the clinical characteristics of oculopharyngodistal myopathy for GCG expansion in poly(A)-binding protein nuclear 1 gene (previously called poly(A)-binding protein 2), the causative gene defect for oculopharyngeal muscular dystrophy. Only one of our five patients had the significant GCG expansion. Thus, oculopharyngodistal myopathy is a genetically heterogeneous disorder, which includes patients with oculopharyngeal muscular dystrophy but, for the most part, is different genetically from oculopharyngeal muscular dystrophy.

A practical enzyme immunoassay for anti-acetylcholine receptor antibodies in myasthenia gravis.

A practical enzyme immunoassay (EIA) has been developed for the measurement of anti-acetylcholine receptor (AChR) antibodies in sera from patients with myasthenia gravis (MG). This system is based on the double antibody technique, using denervated rat muscle AChR labeled with horseradish peroxidase-linked alpha-bungarotoxin (HRP-alpha BGT). This method has the following advantages compared to conventional radioimmunoassay (RIA): (1) HRP-alpha BGT is more stable than [125I]alpha BGT and can be used for at least one year without any loss of the binding activity to AChR and enzymatic activity, (2) the procedure avoids the use of radioactive isotopes, and (3) the equipment for our EIA is more economical than that for RIA.

Reduction of acid sphingomyelinase activity in human fibroblasts induced by AY-9944 and other cationic amphiphilic drugs.

AY-9944 (trans-1,4-bis(2-chlorobenzylaminoethyl)cyclohexane dihydrochloride), a cationic amphiphilic drug, caused a rapid, irreversible and dose-dependent reduction of acid sphingomyelinase activity in normal human fibroblasts without changing the activities of other lysosomal hydrolases tested. Examinations of activities against synthetic substrates and of the pH-dependency of sphingomyelinase in the drug-treated cells also suggested that the reduction of activity was specific to acid sphingomyelinase. Such a specific reduction was also found with 12 other cationic amphiphilic drugs, most of which have been shown to be inducers of experimental phospholipidosis in animals and/or cultured cells. These results strongly suggest that acid sphingomyelinase is involved in the process of drug-induced lipidosis. The reduction of acid sphingomyelinase seemed not to be due to direct inhibition by these drugs, a specific loss of the enzyme into the culture medium, the presence of inhibitor in the drug-treated cells, or impaired synthesis of the enzyme. There was no indication that changes in the catalytic properties of the enzyme, or changes in the requirement of detergents for its activity occurred in the cell. These results suggest that AY-9944 and other cationic amphiphilic drugs may cause the reduction of acid sphingomyelinase activity by inducing an increased rate of degradation of the enzyme or by causing an irreversible inactivation via some undetected factor.

Neoplastic angioendotheliosis of the central nervous system.

A case of neoplastic angioendotheliosis demonstrating unusual manifestations is reported. A 56-year-old male showed recurrent attacks of neurological symptoms including paraplegia, brain-stem symptoms, tonic seizures, aphasia, apraxia and cortical blindness over 2 years. The EEG disclosed transient, periodic, lateralized, epileptiform discharges. Brain CT scan revealed low-density areas mainly in the white matter. Other laboratory examinations were negative except for CSF protein fractions. Post-mortem examination disclosed remarkable intravascular proliferation of atypical cells in the CNS with prominent proliferation of blood vessels and softening. Other organs were not affected, which suggested that the atypical cells had a high affinity to CNS blood vessels.

Antibodies against saline-soluble components of skeletal muscle in myasthenia gravis.

Antibodies against phosphate-buffered-saline extracts (SE) of non-acetylcholine receptor (AChR) skeletal muscle antigens were found in patients with myasthenia gravis (MG). The antigenicity of SE was distributed in three fractions with molecular masses of over 200 kDa, 90-150 kDa and 7-14 kDa on gel filtration. These fractions shared common antigenicities. Further analysis of 90-150 kDa fractions on sodium dodecyl sulphate polyacrylamide gel electrophoresis showed five major bands, ranging from 105 kDa to 275 kDa. The antibodies against SE were detected in 52% (58/112) of the MG patients; incidence and titres were higher in the thymoma group (n = 21; 90% and 0.872 respectively) than in the non-thymoma group (n = 91; 43% and 0.200, P less than 0.001). In patients without a thymoma, these antibodies were frequently observed in late-onset disease and the severe generalized form (P less than 0.01). In 4 of 7 ocular MG patients without anti-AChR antibodies, low but appreciable levels of anti-SE antibodies were found. In 73% (11/15) of generalized MG patients treated with prednisolone and thymectomy, anti-SE antibody titres changed in association with those of anti-AChR antibodies and with the clinical course. Both antibody titres increased synchronously in patients who developed crises.

Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes with acanthocytosis: a clinicopathological study of a unique case.

A case of a unique combination of mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like syndrome (MELAS) with acanthocytosis is reported. Neuropathological examination revealed pellagra-like change in Betz cells, brain-stem neurons and anterior horn cells as well as findings compatible with mitochondrial encephalomyopathies. Abnormal function of nicotinic acid-related enzymes could be the cause of the complicated clinicopathologic findings in this case. This is the first report of MELAS with acanthocytosis.

Familial type I fiber atrophy.

An 11-year-old boy and his 40-year-old mother with congenital, non-progressive muscular weakness and wasting are described. Muscle biopsies from both cases showed a selective atrophy of Type I fibers without any structural change except for very few nemaline bodies. Probably, the neuromuscular disorder in this family is identical to the congenital fiber type disproportion described by Dubowitz and Brooke, but familial Type I fiber atrophy (hypotrophy, or hypoplasia) is considered to be a more appropriate descriptive term for a family with such distinct histochemical characteristics.