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Biomedical subjects

V Askanas

Publications and source records attributed to V Askanas.

At least 127 records · Page 7Linked to original sources
PubMed1980

Human schwann cells in tissue culture: histochemical and ultrastructural studies.

Schwann cells cultures were established from 40 human peripheral nerves that underwent biopsy according to an explant-reexplantation technique that markedly reduces non-Schwann cells and achieves cultures greatly enriched in Schwann cells suitable for a wide range of studies. Described are the growth characteristics and histochemical, ultrastructural, and ultrastructural-cytochemical patterns of normal human cultured Schwann cells from 12 patients with demonstrable peripheral nerve abnormality. These findings serve as a basis of comparison when seeking abnormalities of Schwann cells grown from peripheral nerves of patients with putative dysschwannian neuropathies.

Adolescent↗
PubMed1979

X-linked recessive congenital muscle fiber hypotrophy with central nuclei: abnormalities of growth and adenylate cyclase in muscle tissue cultures.

Muscle cells in cultures established from biopsy specimens of two children with an infantile-fatal form of X-linked recessive muscle fiber smallness with central nuclei showed an unusual ability to proliferate through numerous passages. Ultrastructurally, the cultured muscle fibers appeared very immature even after several weeks. The nuclei were large, the number of ribosomes was greatly increased, the myofibrils remained unstriated, and glycogen was accumulated in large lakes. The plasmalemma bound concanavalin A, alpha-bungarotoxin, and ruthenium red normally, but with tannic acid it did not show the dark binding of mature fibers. Biochemically, in the cultured muscle fibers, beta-adrenergic receptors were quantitatively normal. The level of adenylate cyclase in membranes was less than in cultured normal muscle; this defect could be responsible for impaired control mechanisms resulting in the other abnormalities observed.

Adenylyl Cyclases↗
PubMed1978

Leptomeres in cultured human muscle.

Leptomeres, the laminated structures consisting of bundles of very fine filaments separated into bands about 260 nm wide by periodic transverse dense lines 20--80 nm wide, were observed frequently in cultured muscle fibers of 8 patients with acid maltase deficiency, 4 with sporadic, adult-onset idiopathic "autophagic" vacuolar myopathy (that is not acid-maltase deficient) and one with abnormal mitochondria, but in only one of greater than 50 other cultures of normal and denervated human muscle. They were also induced abundantly in cultured normal human muscle by exposure to 0.5 mM DNP.

Culture Techniques↗
PubMed1978

Reincarnation in cultured muscle of mitochondrial abnormalities. Two patients with epilepsy and lactic acidosis.

Two unrelated 9-year-old boys failed to thrive from ages 5 and 4 years, and had focal cerebral seizures followed by transcent hemipareses. Histochemistry of their muscle biopsies showed "ragged-red" fibers, which ultrastructurally contained clusters of mitochondria having loss of crisp delineation of crista membranes and contained amorphous inclusion material and parallel-packed cristae and sometimes paracrystalline inclusions. In the patients' cultured muscles, similar mitochondrial abnormalities were present. 2,4-Dinitrophenol, introduced to the medium of cultures of normal human muscle, produced mitochondrial abnormalities similar to those of the patients', and the medium of the patients' muscle cultures worsened the mitochondrial abnormalities. This study, in demonstrating a mitochondrial defect reproducible in the cultured muscle fibers and, therefore, intrinsic to the ragged-red muscle fibers themselves, raises the possibility of a collateral mitochondrial defect in CNS cells as part of a multicellular mitochondriopathy.

Acidosis↗
PubMed1977

Muscle-type phosphorylase activity present in muscle cells cultured from three patients with myophosphorylase deficiency.

Skeletal muscle fibers cultured from three patients whose mature fibers are deficient in glycogen myophosphorylase (EC 2.4.1.1) were shown to become rather mature, to have no excessive glycogen accumulation, and to develop signifcant myophosphorylase activity. That activity was characterized electrophoretically and immunologically and shown to be muscle phosphorylase rather than a genetically different type, thereby demonstrating true "rejuvenation" in culture of an enzyme genetically programmed ultimately to be deficient.

Adult↗
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

Improved technique for electron microscopy of cultured cells.

A number of techniques are presented which precise selection and efficient preparation of individual cultured cells for electron microscopy. Techniques described include marking of the living and embedded cells, drilling and mounting cores of embedded material, and improved technique for marking of the selected area on the block face before trimming.

Cells, Cultured↗
PubMed1976

Adult-onset acid maltase deficiency. Morphologic and biochemical abnormalities reproduced in in cultured muscle.

We established muscle-tissue cultures from biopsy of a patient with adult-onset acid maltase deficiency. Morphologically and biochemically, the newly grown fibers of the cultured muscle showed the same abnormalities as those of the biopsied muscle. Light microscopy showed multiple vacuoles filled with acid-phosphatase-positive material; on ultrastructural examination there was abnormal accumulation of glycogen in membrane-bound sacs (secondary lysosomes), some of which also contained dark membranous of homogeneous material. Acid maltase (pH 4.0), a lysosomal enzyme, was undetectable in either cultured or biopsied muscle by maltose hydrolysis, whereas acid phosphatase, also a lysosomal enzyme, was increased in both sources of muscle cells. Cultured muscle fibers demonstrate the same morphologic and biochemical abnormalities characteristic of biopsied muscle, supporting the concept of a biochemically distinct primary myopathy in man.

Acid Phosphatase↗
PubMed1976

Remote effects of focal cancer on the neuromuscular system.

The remote effects of cancer on the neuromuscular system include type II muscle fiber atrophy, dermatomyositis/polymyositis, myasthenia gravis, the facilitating myasthenic syndrome, peripheral neuropathy (including amyloid neuropathy), and possibly amyotrophic lateral sclerosis. The clinical and pathological findings and a number of possible pathokinetic mechanisms of these disorders are discussed. In none is the pathokinetic mechanism known. Hence, much work remains in therapeutically oriented research of the mechanisms in all of the remote effects of cancer on the neuromuscular system.

Amyotrophic Lateral Sclerosis↗
PubMed1975

Chick muscle in tissue culture: the ubiquity of viral infection.

In chick skeletal muscle fibers cultured from embryos of commercially obtained "normal" eggs we have demonstrated numerous C-particles and large amounts of avian leucosis/sarcoma envelope antigen, especially when cultured in the presence of dinitrophenol. C-particles were present in t-tubules, which were possible intracellular viaducts of infection or dissemination and perhaps were the loci of receptors of viral invasion of the cytoplasm and sites of egress. The abundant lace-like membraneous proliferations, probably of t-tubules, usually had C-particles adjacent to or within them and perhaps were virus-provoked. Questioned is the validity of using cultured muscle, or extract, of embryos from ordinary chicken eggs for analysing normal biological phenomena--or conversely, is viral influence "normal" in chick development?

Alpharetrovirus↗
PubMed1975

A new program for investigating adult human skeletal muscle grown aneurally in tissue culture.

With our new "explant-reexplanting" technique, abundant growth of mature human muscle in long-term tissue culture was achieved,and with the "sandwich" technique several histochemical reactions were obtained on serial cross sections of the cultured fibers. An advanced degree of maturation but lack of differentiation into reciprocally staining fiber-types was demonstrated. For electron-microscopic and electronmicroscopic-histochemical study, a method was developed in which the embedded fibers of greatest potential interest were identified by light microscopy and punched out by our specially-designed hollow drill. This selection procedure is critically important when the goal is to study in cultured diseased human muscle: (1) successive stages of development and (2) certain structural changes that often occur only in some fibers and only in certain regions of those fibers. The electronmicroscopic-histochemical appearance of developing cultured muscle fibers correlated well with the fresh-frozen light microscopic histochemical cross-sections and longitudinal whole preparations of similar fibers.

Adenosine Triphosphatases↗
PubMed1975

Distinct subtypes of type I fibers of human skeletal muscle.

We have identified two distinct and consistent type I fiber subtypes in histochemically normal biopsies (vastus lateralis or biceps brachialis) from 12 healthy persons, both sexes, ages 15 to 42. The type I fibers were uniformly light with the regular ATPase (9.4) and uniformly dark with the acid-preincubated reverse ATPase reactions. However, the subtype IA fibers were stained darker than subtype IB fibers with the nicotinamide adenine nucleotide dehydrogenase-tetrazolium reductase, Oil red O, reduced nicotinamide adenine dinucleotide phosphate-tetrazolium reductase, nonspecific esterase, succinic-tetrazolium reductase, nicotinamide adenine dinucleotide-linked malic-tetrazolium reductase, and "nicotinamide adenine dinucleotide-linked lactic-tetrazolium reductase," and stained lighter with the phosphorylase, periodic acid-Schiff for glycogen, and menadione-mediated alpha-glycerophosphate-tetrazolium reductase reactions. The IB fibers were not as light (or as dark, depending on the stain) as any of the type II fibers. In one pathologic case, all the "hypotrophic type I muscle fibers with central nuclei" were subtype IB. In case of chronic infantile spinal atrophy the muscle showed some type-grouping and marked type I fiber predominance--the great majority of type I fibers were subtype IB, among which were islands (subtype-groups) of IA fibers. Subtyping of type I fibers may be informative in evaluating the pathologic process of certain human neuromuscular diseases.

Adolescent↗