Search PubMed⌕ Search

Biomedical subjects

E Ammann

Publications and source records attributed to E Ammann.

10 recordsLinked to original sources
PubMed2000

Cell activation and inflammatory response following traumatic axonal injury in the rat.

In a rat model of traumatic brain injury cell activation was characterized immunohistochemically from 2 h up to 2 weeks. Reactive astrocytosis became apparent perivascularly and in the grey matter within 4h after trauma. Increased OX42 immunoreactivity indicated microglial activation in cortex and hippocampus as early as 4 h, whereas up-regulation of MHC class II (OX6) was evident in white matter tracts at 24 h. Although macrophage (ED1) numbers increased in the meninges and perivascularly, brain infiltration appeared marginal. Accumulation of lymphocytes and granulocytes was not observed. Our results show that traumatic axonal injury induces a rapid and sustained glial activation in the absence of leukocyte infiltration. Thus, cell activation following diffuse trauma strongly differs from that found after focal brain damage, awaiting further functional characterization.

Animals↗
PubMed2000

Antipredatory behavior as an index of heavy-metal pollution? A test using snails and caddisflies.

The loss of behaviors that organisms use to avoid predation may serve as a sensitive indicator of pollution. We tested the hypothesis that a correlation exists in the field between heavy metal levels and antipredator behaviors. We examined the antipredator behavior of aquatic caddisfly larvae and snails at sites in the Coeur d'Alene basin of Northern Idaho which varied in their levels of heavy metals. We tested the antipredator response of Physella columbiana snails at 10 polluted lakes downstream from the Bunker Hill Environmental Protection Agency (EPA) Superfund cleanup site. We then compared their behavior to snails at 14 reference lakes. We placed the snails in a plastic testing apparatus, exposed them to an extract of crushed snail, and then monitored their movements to a normally preferred shaded area. We also tested the behavior of caddisfly larvae from 36 sites from a total of 6 streams/rivers adjacent to the Superfund site. Sites were located upstream and downstream of abandoned mines. We located active larvae of four genera, simulated predation by grasping the animals between thumb and forefinger (the larvae respond to being grasped by withdrawing into their case), lifted them from the water for 3 s, and then placed them in an adjacent, slower section of the stream. We then recorded how long it took each larvae to partially emerge from its case and attempt to move away. Unlike reference site snails, snails from heavy metal-polluted environments failed to exhibit antipredator behaviors in response to crushed conspecifics. These results are consistent with previous laboratory studies. We found no effect of heavy metals on the antipredatory behavior of caddisfly larvae.

Animals↗
PubMed1997

Production of cytokines following brain injury: beneficial and deleterious for the damaged tissue.

A profound inflammatory response is initiated immediately following traumatic brain injury (TBI) and is characterized by the release of several cytokines with pro- and anti-inflammatory functions. In order to elucidate which cytokines are released in the human brain in response to injury as well as in the peripheral compartment, IL-1, IL-6, IL-8, IL-10, TNF-alpha and TGF-beta were monitored in CSF and serum of severely brain-injured patients. Furthermore, we investigated the possible modulation of systemic reactions by IL-6 and the ability of IL-6 and IL-8 to promote the synthesis of nerve growth factor.

Animals↗
PubMed1997

X-ray tubes--continuous innovative technology.

The X-ray tube is one of the most important components in any X-ray system. In the beginning, physicists and physicians used gas ion tubes. The so-called Coolidge tube applied a high vacuum and is still used today. Medical examinations have required continuously improved designs of X-ray tubes (smaller focal spots at a higher output). The principle of the Goetze line focus is still applied in any diagnostic X-ray tube. Different anode materials and the rotating anode contributed to an increased output and reduced exposure time. Bearings needed special attention. Spiral groove bearings are the most advanced design today. The heat storage capacity of the anode and the tube housing assembly influences examination time and patient throughput. Cardiac imaging required less motion blurring in cine film images and increasing radiation exposure in interventional procedures called for measures to reduce dose. Protection against radiation and electric shock has always been a concern of design engineers. Focal spot sizes dedicated to specific applications and heat management within the total tube housing assembly will be future issues. Even with the event of ultrasound and MR technology, X-ray procedures will still be applied for diagnostic and interventional purposes.

Coronary Angiography↗
PubMed1976

The surface membrane of the small intestinal epithelial cell. I. Localization of adenyl cyclase.

The subcellular distribution of adenyl cyclase was investigated in small intestinal epithelial cells. Enterocytes were isolated, disrupted and the resulting membranes fractionated by differential and sucrose gradient centrifugation. Separation of luminal (brush border) and contra-luminal (basolateral) plasma membrane was achieved on a discontinuous sucrose gradient. The activity of adenyl cyclase was followed during fractionation in relation to other enzymes, notably those considered as markers for luminal and contraluminal plasma membrane. The luminal membrane was identified by the membrane-bound enzymes sucrase and alkaline phosphatase and the basolateral region by (Na+ + K+)-ATPase. Enrichment of the former two enzymes in purified luminal plasma membrane was 8-fold over cells and that of (Na+ + K+)-ATPase in purified bisolateral plasma membranes was 13-fold. F--activated adenyl cyclase co-purified with (Na+ + K+)-ATPase, suggesting a common localization on the plasma membrane. The distribution of K+-stimulated phosphatase and 5'-nucleotidase also followed (Na+ + K+)-ATPase during fractionation.

Adenosine Triphosphatases↗
PubMed1976

Differences in neutral amino acid and glucose transport between brush border and basolateral plasma membrane of intestinal epithelial cells.

A comparison of L-valine and D-glucose transport was carried out with vesicles of plasma membrane isolated either from the luminal (brush border) or from the contra-luminal (basolateral) region of small intestinal epithelial cells. The existence of transport systems for both non-electrolytes was demonstrated by stereospecificity and saturability of uptake, as well as tracer coupling. Transport of L-valine and D-glucose differs markedly in the two types of plasma membrane with respect to stimulation by Na+. The presence of Na+ stimulated initial L-valine and D-glucose uptake in brush border, but not in basolateral membrane. Moreover, an electro-chemical Na+ gradient, oriented with the lower potential on the inside, supported accumulation of the non-electrolytes above medium concentration only in the brush border membrane. L-Valine and D-glucose transport also were saturated at lower concentrations in brush border (10-20 mM) than in basolateral plasma membranes (30-50 mM). A third difference between the two membranes was found in the effectiveness of known inhibitors of D-glucose transport. In brush border membranes phlorizin was more potent than phloretin and 2', 3', 4'-trihydroxy-4-methoxy chalcone and cytochalasin B did not inhibit at all. In contrast, with the basolateral plasma membranes the order of potency was changed to phloretin = 2',3',4'-trihydroxy-4-methoxy chalcone greater than cytochalasin B greater than phlorizin. These results indicate the presence of different types of transport systems for monosaccharides and neutral amino acids in the luminal and contra-luminal region of the plasma membrane. Active transepithelial transport can be explained on the basis of the different properties of the non-electrolyte transport systems in the two cellular regions and an electro-chemical Na+ gradient that is dependent on cellular metabolism.

Animals↗