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Biomedical subjects

W Heller

Publications and source records attributed to W Heller.

At least 73 records · Page 4Linked to original sources
PubMed1990

FXII.

The plasma protein FXII (Hageman factor) has been shown to be linked with the plasma defence systems of coagulation, fibrinolysis, kallikrein-kinin and complement. It can be activated by surface contact activation and in solution. Surface contact activation is a complex phenomenon involving negatively charged surfaces, FXII, high molecular weight kininogen and plasma kallikrein. Fluid-phase activation can be effected by a variety of serine proteases. In both types of activation the FXII zymogen is converted to active enzymes. FXII levels in plasma are low or undetectable in both inherited deficiencies and in a variety of clinical conditions. FXII levels can also be elevated in some clinical conditions. Although discovered as a clotting protein FXII appears to play an important role in the kallikrein-kinin and fibrinolytic systems and also has effects on cells. Recent studies suggest that therapeutic blockade of activation of FXII can be of benefit in certain clinical conditions.

Animals↗
PubMed1990

Biochemical response of Norway spruce (Picea abies (L.) Karst.) towards 14-month exposure to ozone and acid mist: part I--Effects on polyphenol and monoterpene metabolism.

Three-year-old clonal Picea abies (L.) Karst. plants, grown either on a sandy (No. 1) or on a calcareous (No. 2) soil, were treated with ozone (100 microg m(-3) and peaks of up to 360 microg m(-3)) and acid mist (pH 3.0) over two vegetation periods. Needles of the current (1987) and previous (1986) year were analysed at the end of the experiment for biosynthetic enzymes and in vivo activity of the phenylpropanoid pathway, for products of polyphenol metabolism (clones 11 and 14), and for mono- and sesquiterpenes (clones 14 and 16). 1. Polyphenol metabolism. The activity of cinnamyl alcohol dehydrogenase, an enzyme of the lignin pathway, was increased by the treatment by up to 83% in the needles of both age classes. Chalcone synthase was measured in mature tree material for the first time. This enzyme, as well as phenylalanine ammonia-lyase activities and the content of catechin, astringin, isorhapontin, picein and p-hydroxyacetophenone, exhibited no significant treatment-dependent differences. However, soil and age-class dependent differences occurred. Pulse-labelling experiments with l[U-(14)C]phenylalanine and [2-(14)C]acetate were carried out at four different stages of shoot development and showed label incorporation into (+)-catechin and proanthocyanidins. There was no effect of the ozone and acid mist treatment. 2. Monoterpenes. The content of needle terpenes was generally diminished by the ozone and acid mist treatment. Other factors tested, such as clone, needle age and soil, exerted a highly significant influence on the content of most of the needle monoterpenes.

Journal Article↗
PubMed1990

Autistic children and their first-degree relatives: relationships between serotonin and norepinephrine levels and intelligence.

Whole-blood serotonin (5-HT) and plasma norepinephrine (NE) were studied in 16 autistic children, 21 siblings of autistic children, and 53 parents of autistic children. Both plasma NE and whole-blood 5-HT were negatively correlated with vocabulary performance. Whole-blood 5-HT and plasma NE did not differ between autistic children with or without histories of self-injurious behavior or decreased pain sensitivity. Eighteen subjects were hyperserotonemic (whole-blood 5-HT greater than 270 ng/ml). For these subjects, plasma NE was significantly higher than for subjects without hyperserotonemia. Seven of 10 families with one hyperserotonemic member had two or more hyperserotonemic members. Observations of familiarity of whole-blood 5-HT suggest that larger-scale and more focused study of whole-blood 5-HT as a possible genetic marker may be productive.

Adolescent↗
PubMed1989

Aesthetic preference and picture asymmetries.

Previous research has shown that when right-handed subjects prefer one orientation of a picture over its mirror image, the more interesting or important content is on the right. Location of content, however, is only one of a number of possible asymmetric aspects of picture composition. To determine whether the relationship between aesthetic preference and cerebral asymmetry is affected by the interaction of different aspects of asymmetric information in a slide, the present study examined both asymmetry of content and asymmetry of motion. The results indicated that asymmetry of both content and motion combined to influence orientation preferences of right-but not left-handers. Thus, at least two asymmetric components of picture composition interact with brain organization to influence aesthetic judgements.

Esthetics↗
PubMed1989

Alterations in electrolyte and trace-element concentrations during simulated extracorporeal blood circulation.

In our studies with simulated extracorporeal blood circulation we observed damaging effects on blood cells, especially under oxygenating conditions. In order to characterize these effects we also analysed electrolyte and trace-element concentrations in plasma during and after simulated extracorporeal blood circulation. Highest resorption effects for magnesium and highest desorption effects for calcium, copper and iron are found with oxygen gas flow in the system. Membrane permeability for electrolytes seems to be induced as well. Cellular damage due only to mechanical stress within the perfusion system can be neglected.

Calcium↗