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Biomedical subjects

H Lang

Publications and source records attributed to H Lang.

At least 199 records · Page 11Linked to original sources
PubMed1988

Expression of env sequences of the bovine leukemia virus (BLV) in the yeast Saccharomyces cerevisiae.

DNA sequences of the envelope (env) gene of the bovine leukemia virus (BLV) were expressed in the yeast Saccharomyces cerevisiae. Two yeast promoters, the repressible PHO5 promoter and the constitutive PGK promoter, were used to construct four expression plasmids comprising either a sequence of the surface antigen gp51 or a (gp51 + gp30) sequence. The expressed heterologous gene products were characterized by Western blot analysis and competitive radioimmunoassay. By means of Northern blot analysis the steady-state level of env-specific mRNA was analysed. The highest expression rate was obtained from recombinant plasmid YEpSG 94 comprising a gp51 sequence--a 630 base pair fragment containing 70% of the gp51 but lacking the N terminus--as well as the PHO5 promoter including PHO5 signal sequence and the PHO5 terminator. The recombinant gp51 was partially glycosylated but the PHO5 signal peptide did not seem to be cleaved off. No immunoreactive material could be found in the periplasm or in the culture medium. By means of monoclonal antibodies directed against eight different epitopes of viral gp51, all four sequential antigenic determinants were detected in the AH 216 (YEpSG 94) expression product.

Amino Acid Sequence↗
PubMed1988

Linkage studies in a new X-linked myopathy, suggesting exclusion of DMD locus and tentative assignment to distal Xq.

We here report linkage studies in a family suffering from a recently described hereditary muscle disease named X-linked myopathy with excessive autophagy (XMEA). Significant lod scores excluding linkage to the Duchenne-Becker muscular dystrophy locus were found. Several other loci on the short and long arms of the X chromosome produced negative lod scores, whereas probe DX13-7 defining locus DXS15 showed no recombinants and a lod score of z = 0.903 at theta = .0. Further studies should be done to determine whether the gene for XMEA is (1) located at Xq and (2) caused by a mutation of the Emery-Dreifuss muscular dystrophy gene, which has been assigned to the same region.

Autophagy↗
PubMed1987

Minicore myopathy with dominant inheritance.

Minicore disease (multicore disease) is a benign myopathy characterized by segmental muscle fibre degeneration with disruption of myofibrils and loss of mitochondria. The disease is generally thought to occur either sporadically or follow an autosomal recessive mode of inheritance. We describe 2 patients, a mother and her son, with essentially non-progressive weakness of both proximal and distal muscles. Biopsies from both patients showed focal defects of oxidative enzyme activity as well as focal disturbances of cross-striation typical of minicore myopathy. Normal fibre type differentiation was lacking. Three other families reported in the literature suggest dominant inheritance of minicore myopathy or closely related disease.

Adolescent↗
PubMed1987

Gene analysis and the clinical chemist.

Knowledge of gene analysis methods and concepts will be important to the clinical chemist in the near future. Currently most gene analyses must be performed by indirect techniques, using polynucleotide probes hybridizing close to or on the disease gene but not on the position of the mostly unknown gene mutation (restriction fragment length polymorphism analysis). The sensitivity and specificity of such assays are affected by biological and methodologic factors, and are being continually improved. Preventive medicine is a promising area for gene analysis which will possibly fit well into the domain of clinical chemistry. The application of nucleotide hybridization analysis in tissue matching for organ transplantation, and in the detection and differential diagnosis of malignancies is in its early stages. A very promising, and rapidly emerging, technology is the direct detection and differentiation by gene probing of bacteria and viruses in medical microbiology. Guidelines for the ethical problems of gene analysis already exist within the field of medical ethics.

Chemistry, Clinical↗
PubMed1986

Different behavior of the octadeoxynucleotides d(A-T)4 and d(T-A)4 at high concentrations of cesium fluoride.

High CsF concentrations induce a zig-zag double helix, which we call X-DNA, in poly d(A-T) and also in the octadeoxynucleotide d(T-A)4 while d(A-T)4 remains fixed in a B-DNA form. Intermolecular contacts promote the B-X isomerization of the former oligonucleotide but induce aggregation of the latter. This indicates that there is an intramolecular factor, presumably base stacking in the T-A steps, stabilizing the X-DNA conformation.

Cesium↗
PubMed1986

Granulocyte elastase as a new biochemical marker in the diagnosis of chronic joint diseases.

Human granulocyte elastase (EC 3.4.21.37) is released from granulocytes in large amounts in chronic inflammatory joint diseases and is therefore of special pathogenic and diagnostic importance. In order to examine the diagnostic significance of this enzyme as a clinico-chemical parameter, we determined the concentration of granulocyte elastase in complex with alpha 1-proteinase inhibitor by an enzyme immunoassay in synovial fluids and plasma of patients with chronic joint diseases. In inflammatory synovial fluids the concentration of complexed elastase correlates well with the granulocyte number and may increase to an extremely high level. In 90% of patients with manifest rheumatoid arthritis increased elastase levels are also observed in the plasma, probably due to the large gradient between the synovial fluid and plasma concentration, whereas in osteoarthrosis normal plasma concentrations were observed. Thus, these results indicate that normal plasma concentrations in patients with chronic joint diseases exclude the diagnosis of rheumatoid arthritis with high probability. The simultaneous determination of complexed elastase in plasma and synovial fluid improves the nosological differentiation of chronic joint diseases. Elastase activity on a specific chromogenic substrate, which was found in many inflammatory synovial fluids, is mainly attributed to elastase alpha 2-macroglobulin complexes. In some purulent synovial fluids, however, we were able to detect free elastase, which has been shown to play an important role in the destruction of articular cartilage.

Adolescent↗
PubMed1986

Quantitative analysis of individual motor unit potentials: a proposition for standardized terminology and criteria for measurement.

The physiology of the motor unit potential (MUP) is reviewed. The aim is to identify the electrophysiological events in the motor unit that generate the individual parts of the MUP. This is based on insight gained from new experimental techniques, such as single-fiber electromyography (EMG), scanning EMG, and simulation studies of the MUP. A terminology for the different parts of the MUP is also suggested, and nine parameters used to describe different features of the MUP are delineated: duration, spike duration, amplitude, area, spike area, phases, turns, satellites, and variability. Technical aspects, such as electrode type, filtering, and sampling rate of the computers, are discussed as well. In Appendix A, different manual and computer-aided methods for quantitative MUP analysis are described. Despite minor systematic differences between the methods, MUP durations measured by different methods correlate highly with each other (Appendix B). The manual and computer-aided methods have comparable variability between repeated measurements.

Action Potentials↗
PubMed1986

Quantitative vibratory perception thresholds of healthy and epileptic children.

Quantitative vibratory perception threshold (VPT) measurements were performed on 102 healthy children and 79 children receiving anti-epileptic medication. Their ages ranged from three to 16. The VPTs correlated significantly with age and height. The rise in VPT with age may be associated with decreased receptor density. The level of mental alertness seemed to have no significant effect on vibratory perception. Only three of the children on anti-epileptics showed elevated VPTs. On the basis of this study, epileptic children seem to be free of the adverse effects of medication which occur later in adulthood. Children as young as three or four are quite capable of co-operating in this examination. The method can be recommended for use in follow-up studies of children and as a diagnostic aid when a disturbance of the sensory tract is suspected.

Adolescent↗
PubMed1986

Vibratory perception threshold in patients with mild multiple sclerosis.

The vibratory perception threshold (VPT) was measured bilaterally on both the upper and lower extremity in 69 patients with mild multiple sclerosis. In the case of the lower extremities the VPT measurements were closely correlated with qualitative vibratory perception measurements performed with a tuning fork; in the upper extremities the association was weak. The VPT was abnormal at least in one extremity in 38% of the patients. Quantitative VPT measurement seem to be a suitable technique for the detection of sensory symptoms of central origin.

Adolescent↗
PubMed1986

Granulocyte proteinases as mediators of unspecific proteolysis in inflammation: a review.

In severe inflammatory response, various blood and tissue cells, including polymorphonuclear granulocytes, release lysosomal proteinases, extracellularly and into the circulation. Such enzymes, as well as normally intracellular oxidizing agents produced during phagocytosis, enhance the inflammatory response by degrading connective tissue structures, membrane constituents and soluble proteins by proteolysis or oxidation. We first used polymorphonuclear elastase (E) as a marker of such release reactions. The liberated proteinase competes with susceptible substrates, including alpha 1-proteinase inhibitor (alpha 1PI) and alpha 2-macroglobulin, and is eliminated finally as inactive enzyme-inhibitor complexes by the reticulo-endothelial system. Using an enzyme-linked immunosorbent assay, we determined the plasma levels of E-alpha 1PI following major abdominal surgery, multiple trauma and pancreatogenic shock. Whereas the operative trauma was followed by up to 3-fold increase of the E-alpha 1-PI, postoperative septicemia was associated with a 10 to 20 fold increase. The increase of E-alpha 1-PI and a concomitant decrease of plasma factors, such as antithrombin III, clotting factor XIII and alpha 2-macroglobulin, were correlated. Multiple trauma causes a substantial increase of E-alpha 1-PI up to 14 hours after accident. The released elastase seems to correlate with severity of injury, but assessing the relationship to consumption of plasma factors is complicated by concomitant transfusions. In acute pancreatitis, peaks, of E-alpha 1-PI coincide with a massive consumption of antithrombin III and alpha 2-macroglobulin during shock.

Blood Proteins↗