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Biomedical subjects

M Otto

Publications and source records attributed to M Otto.

At least 163 records · Page 9Linked to original sources
PubMed1994

Proximal myotonic myopathy: a new dominant disorder with myotonia, muscle weakness, and cataracts.

We describe three families with a dominantly inherited disorder. Affected individuals have myotonia, proximal muscle weakness, and cataracts. There was no abnormal CTG repeat expansion of the myotonic dystrophy (DM) gene in DNA from blood and muscle. The structure of the three families permitted linkage analysis, and there is no linkage to the gene loci for DM or to the loci for the muscle chloride channel disorders or muscle sodium channel disorders. The collection of symptoms in these three families seems to represent a new disorder.

Adult↗
PubMed1994

[Endemic mercury burden caused by a bleaching ointment in Balken refugees].

In two camps in Ibbenbüren occupied by refugees from Balkan countries we found in 121 inhabitants, among them 56 children, high mercury concentrations in urine and blood. The median of the urinary concentrations was 12 micrograms/l (range: 0.15-770 micrograms/l) or 11.4 micrograms/g creatinin (range: 0.2-446 micrograms/g). 12 adults and 15 children had values above 50 micrograms/l. As source, a mercury-containing bleaching ointment, sold by foreign vendors, was identified. Mercury concentrations in several samples of this ointment ranged from 708 to 17,200 micrograms/g. Similar exposure to mercury may occur elsewhere. Hence, chronic mercury poisoning should by taken into differential diagnostic consideration.

Adolescent↗
PubMed1993

Design of a glucose minisensor based on streptavidin-glucose oxidase complex coupling with self-assembled biotinylated phospholipid membrane on solid support.

A simple and fast procedure to prepare a glucose-sensitive minielectrode is presented. It is based on a biotin-modified phospholipid bilayer to which a streptavidin-glucose oxidase complex is coupled. The assay is based on the electrochemical detection of enzymatically generated hydrogen peroxide at the potential +670 mV. In the case of an air-saturated buffering solution the response to glucose was measured up to 50 mmol.L-1, with a linear portion up to 7 mmol.L-1. The influence of oxygen tension, pH, and temperature as well as possibly interfering substances was investigated. The prospect usage for the measurement of blood and urine was tested.

Bacterial Proteins↗
PubMed1993

Evidence for genetic homogeneity in autosomal recessive generalised myotonia (Becker).

Generalised myotonia Becker (GM) is an autosomal recessively inherited muscle disorder. Affected subjects exhibit myotonic muscle stiffness in all skeletal muscles with marked hypertrophy in the legs. A transient muscle weakness is particularly pronounced in the arms and hands and is a typical symptom of the disorder. Recently, we showed complete linkage of the disorder GM to the gene (CLCN1) coding for the skeletal muscle chloride channel CLC-1 and the TCRB gene on chromosome 7 in German families. In the study presented here we performed linkage analysis on 14 new GM families. The GM locus was again completely linked to both the CLCN1 and the TCRB gene in all families with a combined lod score of Z = 9.26 at a recombination fraction of theta = 0.00. This confirms our previous data and supports the hypothesis that GM is a genetically homogeneous disorder. The previously detected T to G missense mutation is found on 15% of the 66 GM chromosomes counted so far.

Alleles↗
PubMed1993

[Traumatic false aneurysm of the subclavian artery].

Injuries of the subclavian artery are rare; still rarer are aneurysms of the subclavian artery due to blunt or penetrating trauma. Diagnosis can be performed by careful clinical investigation. To identify precisely the nature and site of the injury, angiography and CT are necessary. Rarely associated injuries, such as arteriovenous fistulas, can be recognized by means of these diagnostic tools. This will be of value for planning the surgical approach, which varies with the anatomical site of the injury and the kind of accompanying damage. Subclavian aneurysms should be treated surgically, because embolic or thrombotic complications may threaten the extremity and the brain.

Adolescent↗
PubMed1992

The skeletal muscle chloride channel in dominant and recessive human myotonia.

Autosomal recessive generalized myotonia (Becker's disease) (GM) and autosomal dominant myotonia congenita (Thomsen's disease) (MC) are characterized by skeletal muscle stiffness that is a result of muscle membrane hyperexcitability. For both diseases, alterations in muscle chloride or sodium currents or both have been observed. A complementary DNA for a human skeletal muscle chloride channel (CLC-1) was cloned, physically localized on chromosome 7, and linked to the T cell receptor beta (TCRB) locus. Tight linkage of these two loci to GM and MC was found in German families. An unusual restriction site in the CLC-1 locus in two GM families identified a mutation associated with that disease, a phenylalanine-to-cysteine substitution in putative transmembrane domain D8. This suggests that different mutations in CLC-1 may cause dominant or recessive myotonia.

Amino Acid Sequence↗
PubMed1991

Linkage data suggesting allelic heterogeneity for paramyotonia congenita and hyperkalemic periodic paralysis on chromosome 17.

Paramyotonia congenita (PC), an autosomal dominant non-progressive muscle disorder, is characterised by cold-induced stiffness followed by muscle weakness. The weakness is caused by a dysfunction of the sodium channel in muscle fibre. Parts of the gene coding for the alpha-subunit of the sodium channel of the adult human skeletal muscle (SCN4A) have been localised on chromosome 17. To investigate the role of this gene in the etiology of PC, a linkage analysis in 17 well-defined families was carried out. The results (zeta = 20.61, theta = 0.001) show that the mutant gene responsible for the disorder is indeed tightly linked to the SCN4A gene. The mutation causing hyperkalemic periodic paralysis (HyperPP) with myotonia has previously been mapped to this gene locus by the same candidate gene approach. Thus, our data suggest that PC and HyperPP are caused by allelic mutations at a single locus on chromosome 17.

Alleles↗
PubMed1991

Focal blockade of single unit synaptic transmission by iontophoresis of antagonists.

We have assessed the use of iontophoresis for investigating the pharmacology of synaptic transmission from individual presynaptic neurones in-vivo, by modifying extracellular focal synaptic potentials (FSPs) recorded by spike-triggered averaging. FSPs from two types of excitatory neurone (muscle spindle primary afferents and expiratory bulbospinal neurones) and from one inhibitory interneurone were studied in the thoracic ventral horn of anaesthetized cats. The antagonist of excitatory amino acids at non-NMDA receptors, DNQX, blocked the FSPs from the first two, as did bicuculline for the third. Thus the FSPs were generated by excitatory amino acids acting via non-NMDA receptors and GABA, respectively. The postsynaptic neurones were probably motoneurones. Merits and limitations of the method are discussed.

Animals↗
PubMed1991

Confirmation of linkage of hyperkalaemic periodic paralysis to chromosome 17.

Linkage studies were performed in six European families with hyperkalaemic periodic paralysis (PPII) with myotonia, an autosomal dominantly inherited disorder characterised by episodic weakness. The weakness is caused by non-inactivating sodium channels of reduced single channel conductance of the muscle fibre membrane. Recently, portions of the gene coding for the alpha subunit of the sodium channel of the adult human skeletal muscle (h-Na2) have been cloned and localised on chromosome 17q with no recombinants to the human growth hormone locus (GH1). Linkage between these two chromosome 17 markers and the disease was shown in our families (Z = 7.14, 0 = 0.00). These results, combined with the linkage data of a single large American family, suggest that the disease is caused by dominant mutations of the adult sodium channel, and that it is probably a genetically homogeneous disorder. Hyperkalaemic periodic paralysis is the first non-progressive myotonic disorder to be localised on the human genome.

Chromosomes, Human, Pair 17↗
PubMed1991

Influence of hypergravity on the pH profile and proteolytic activity of the avian gastrointestinal tract.

The present study deals with the effect of hypergravity (2xg) on the pH and on the proteolytic activity in the digesta of the gastrointestinal tract of Japanese quails during intense growth. The birds were raised on a semisynthetic diet containing free amino acids (A) and a commercial diet (B). During days 35 till 40 post-hatching the quails were exposed to hypergravity (2xg) using a specially designed centrifuge. On days 40 (experimental group, 2xg) and 41 (control group, 1xg) the animals were sacrificed. The pH of the digesta in various segments of the gastrointestinal tract was measured by means of a semi-microelectrode. Total proteolytic activity was determined by means of azo-dye-modified proteins serving as general proteolytic substrates. Hypergravity leads in general to an alkalization of digesta in various parts of the gastrointestinal tract. In case of the gizzard and duodenum (diet A) and also in the distal jejunum (diet B) the differences are significant. With both diets, hypergravity leads to a considerable decrease in the total proteolytic activity. The reduction is most expressed in the duodenum and jejunum. Changes in the pH of digesta compensate for the decrease in the proteolytic activity. This may explain why hypergravity per se does not seem to impair growth of the Japanese quails.

Amino Acids↗
PubMed1990

Quantification of proliferative and suppressive responses of human T lymphocytes following ConA stimulation.

The mitogenic response of human T lymphocytes to graded doses of concanavalin A (ConA) has been measured by means of an MTT tetrazolium dye metabolic assay. Three groups of healthy subjects, representing children, younger adults and elderly persons, were investigated. It was shown that a typical bell-shaped course of the ConA dose-response curve is the result of a proliferative response to suboptimal concentrations of ConA and a toxic action of ConA at supraoptimal concentrations. The ascending part of the response curve reflects in its shape the regulatory interaction of responding cells. A decrease in suppressive functions is accompanied by a shift of this part of the curve to lower concentrations of ConA. By means of a mathematical model derived from enzyme kinetics, an attempt was made to quantify the suppressive functions from the course of the individual dose-response curve. It was found that after suitable data processing, suppression-related shape changes can be assigned to a single parameter. The value of this parameter as a diagnostic tool was tested in a study of the age dependence of human T lymphocyte responses to ConA. While the proliferative response decreased with age, the suppressive functions exhibited their maximum effect in the group of adults. Thus it could be demonstrated that ConA induced proliferative and suppressive responses are due to two different pathways which can be independently extracted from the dose-response curve.

Aging↗
PubMed1990

[Polychemotherapy of non-small cell bronchial cancer with mitomycin C, ifosfamide and vindesine].

The results of antineoplastic polychemotherapy in non-small-cell carcinomas of the lungs revealed on overall remission rate of 42.1%, with a distribution from limited to extensive disease of approximately 32% to 58%. Severe undesired side effects of the treatment were not observed, the duration of remission was, on average, 78 days, and the survival period 101 days.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1989

Utilisation of free and protein dietary lysine in chicks estimated with isotopes.

1. Utilisation of supplementary free L-lysine hydrochloride was estimated in growing chicks and compared to that of protein-bound lysine. The technique used is based on the oxidative catabolism of either free (U-14C)-L-lysine or the labelled lysine incorporated into yeast proteins. 2. The animals received a wheat-wheat gluten diet which was L-lysine-supplemented with either unlabelled yeast proteins or a mixture of synthetic amino acids simulating the yeast proteins or L-lysine hydrochloride alone. 3. At 13 and 15 days after hatching, expiry of (14C)--carbon dioxide was followed 8 h after dosing with the appropriate radiolabelled diet. After 4 h, 0.66% of the protein-bound and 5.3 to 5.7% of the free lysine radioactivity appeared as 14C--carbon dioxide. 4. It is concluded that under these conditions lysine from both sources was utilised more efficiently than had been assumed hitherto, protein-bound lysine being slightly better utilised than free lysine.

Animal Feed↗