PubMed Health⌕ Search

Biomedical subjects

A N Bender

Publications and source records attributed to A N Bender.

17 recordsLinked to original sources
PubMed1979

Cholinergic dysautonomia and Eaton-Lambert syndrome.

Cholinergic autonomic function was abnormal in a 47-year-old woman with Eaton-Lambert syndrome (ELS), not associated with carcinoma. Pupillary constriction to light and accommodation, sweating, lacrimation, and salivation were all affected. There was no evidence of Sjogren syndrome or botulinum intoxication. The defect of acetylcholine release from presynaptic terminals in the Eaton-Lambert syndrome may not be restricted to the neuromuscular junction of skeletal muscle.

Cholinergic Fibers↗
PubMed1978

Nemaline (rod) myopathy: the need for histochemical evaluation of affected families.

Histochemical changes in the mother of a patient with nemaline myopathy were used to identify her as the gene carrier even though rod-bodies were not present in her muscle biopsy and she was not weak. The patient and her mother both had marked type I fiber predominance with large groups of type I fibers present. Histochemical changes known to occur in nemaline myopathy include smallness and predominance of type I fibers. Such changes support the concept that this disease may result from subtle defects in innervation since fiber types are determined by innervation. Although this disease is thought to be transmitted by autosomal dominant mode, lack of male-to-male transmission and a predominance of female cases in the literature suggest that this may be (1) an X-linked dominant, (2) a sex-influenced autosomal dominant, or (3) an autosomal dominant which is semilethal in males. The family described here is the first in which a presumably affected parent showed only the histochemical change without rod-bodies, thus emphasizing the importance of histochemical evaluation of relatives' biopsies for genetic counseling.

Biopsy↗
PubMed1978

Histochemistry and acetylcholine receptor distribution in normal and denervated monkey extraocular muscles.

In monkey extraocular muscles (EOM), a battery of histochemical reactions delineates three muscle fiber types, coarse, fine, and granular. Normal EOM are compared with EOM denervated by intracranial oculomotor nerve section. The experimentally denervated EOM fibers did not show the constellation of histologic responses typical of denervated limb muscle, making a diagnosis of a denervation process in EOM muscle very difficult. Although the denervated fine and granular fibers (but not the coarse fibers) develop diffuse extrajunctional acetylcholine receptors (AChR) following experimental denervation, this is not a reliable criterion of denervation because not all of those fibers developed it and they did not show it beyond a 12-week period following nerve section; moreover, myopathic mechanisms have previously been shown capable of provoking diffuse extrajunctional AChR in limb-muscle fibers.

Acetylcholine↗
PubMed1977

Acetylcholine receptors of aneurally cultured human and animal muscle.

We describe the diffuse nonjunctional distribution of AChR molecules of aneurally cultured human and animal muscle and the influence of sera from myasthenia grivis patients and rabbits with experimental autoimmune myasthenia gravis on binding of alphaBT to diffuse nonjunctional AChR. One-hour incubation of myasthenia gravis seria resulted in blocking of the alphaBT-immunoperoxidase staining of their AChRs, while incubation in normal sera did not. Aneurally cultured muscle can aid studies of regenerating fibers in normal muscle compared with those of muscles in neuromuscular diseases, and also act as an environmentally controlled test object for demonstrating the effect of circulating pathogenic factors.

Animals↗
PubMed1977

Muscle fiber hypotrophy with intact neuromuscular junctions. A study of a patient with congenital neuromuscular disease and ophthalmoplegia.

An infant born with severe but nonprogressive somatic and cranial muscle weakness including bilateral external ophthalmoplegia was studied with a motor-point muscle biopsy. There was a strinking generalized decrease in the size of muscle fibers (hypotrophy), most marked in the type I fibers. Many of the small fibers were immature, resembling myotubes. Neuromuscular junctions on severely hypotrophic fibers were normal with esterase staining and by ultrastructural criteria. Although these are unusual clinical and biopsy characteristics, this infant's condition bears a resemblance to two other congenital nonprogressive neuromuscular diseases:myotubular myopathy and congenital fiber type disproportion. In these conditions and in our patient, there is no primary degenerative process affecting nerve or muscle but, rather, an apparent lack of maturation of fetal muscle fibers, indicating a defective normal trophic interaction between nerve and muscle.

Biopsy↗
PubMed1976

Extrajunctional acetylcholine receptors. Alterations in human and experimental neuromuscular diseases.

Diffuse extrajunctional acethycholine receptors (AChR) of skeletal muscle fibers were readily visualized by light and electron microscopy in muscle biopsy specimens of experimental denervation and human denervating diseases by use of an alpha-bungarotoxin immunoperoxidase technique. In peripheral neuropathies and various motor neuron diseases, a significant number of muscle fibers appearing denervated by histochemical criteria have diffuse extrajunctional AChR like those experimentally denervated by cutting the motor nerve supply. In portions of muscle fibers experimentally deprived of neuronal influence by direct injury, diffuse extrajunctional AChR developed, demonstrating that a denervation-like diffuse appearance of extrajunctional AChR can develop other than with neuronal damage, ie, it can be myogenous. Similar extrajunctional AChR was seen in some regenerating fibers of human myopathies, especially inflammatory myopathies.

Amyotrophic Lateral Sclerosis↗
PubMed1976

Light-cored dense particles in mitochondria of a patient with skeletal muscle and myocardial disease.

A 15-year-old boy with skeletal muscle and myocardial disease was found to have large numbers of abnormal muscle mitochondria, the distinguishing feature of which was the presence of many light-cored dense particles. These particles bore a marked resemblance to those seen in situations where mitochondria accumulate calcium. If that is what they were, it remains to be determined whether such an accumulation of calcium, or other mitochondrial abnormality, played a role in the patient's muscle weakness. Alternatively, the granules might have represented evidence of virus involvement of the mitochondria, but this seems less likely.

Adolescent↗
PubMed1976

Immunoperoxidase localization of alpha bungarotoxin: a new approach to myasthenia gravis.

The IPBT method has made it possible to precisely visualize the AChR. Normal distribution of AChR is at the peaks of the postjunctional folds of the muscle sarcolemmal membrane with a small amount present on the axonal tip as well. Denervated muscle fibers have extrajunctional AChR. In MG, there are also denervated-appearing fibers but these do not have extrajuctional AChR with the IPBT stain. To explain this, we have been able to demonstrate a serum factor capable of blocking the binding of alpha-BuTx to the AChR and have shown for the first time that this factor is capable of acting at the neuromuscular junction itself. This blocking factor may play a major role in causing the weakness of MG.

Acetylcholine↗
PubMed1976

Antibodies to nucleic acids in myasthenia gravis.

An increased frequency of antibodies to native DNA, thymocytes, and striated muscle was found in patients with myasthenia gravis (MG). The prevalence of such antibodies lends considerable support to the concept of MG as an autoimmune disorder and militates in favor of major abnormalities in the thymic dependent immune system. There was no correlation between serum-blocking activity to acetylcholine receptor protein and antibodies to thymocytes.

Acetylcholine↗
PubMed1976

The acetylcholine receptor in normal and pathologic states. Immunoperoxidase visualization of alpha-bungarotoxin binding at a light and electron-microscopic level.

Acetylcholine receptor now can be visualized in the muscle sarcolemmal membrane with the use of an immunoperoxidase staining of alpha-bungarotoxin (alpha BT), a substance that binds specifically to the acetylcholine receptor. This technique has allowed new observations in various neuromuscular diseases in which the acetylcholine receptor is affected. In normal muscle, the acetylcholine receptor is confined to the neuromuscular junction. In both experimental denervation and human denervating illnesses, the acetylcholine receptor becomes present diffusely along the muscle sarcolemmal membrane in denervated fibers. In myasthenia gravis, a circulating factor that blocks alpha BT binding to the acetylcholine receptor of either normal neuromuscular junctions or denervated sarcolemmal membranes is present in 68 percent of serums tested.

Animals↗