Spontaneous inclusion body hepatitis in young tamarins: I. Morphological study.

Over a period of 4 years approximately 60% of the new born and juvenile animals in a breeding colony of tamarins (Saguinus fuscicollis) died a sudden death. Histological examination at necropsy revealed interstitial hepatitis in 22 of the 30 young animals of the present study. The hepatocytes contained intranuclear inclusion bodies in 12 of the 22 cases. Upon ultrastructural examination, tubulovesicular structures and amorphous material were found in the nuclei. The endoplasmic reticulum had proliferated and was closely associated with undulating curved membranes. These morphological alterations resemble those reported in chimpanzees experimentally infected with NANB hepatitis viruses.     

On quantitative effects of RNA shape abstraction

Over the last few decades, much effort has been taken to develop approaches for identifying good predictions of RNA secondary structure. This is due to the fact that most computational prediction methods based on free energy minimization compute a number of suboptimal foldings and we have to identify the native folding among all these possible secondary structures. Using the abstract shapes approach as introduced by Giegerich et al. (Nucleic Acids Res 32(16):4843–4851, 2004), each class of similar secondary structures is represented by one shape and the native structures can be found among the top shape representatives. In this article, we derive some interesting results answering enumeration problems for abstract shapes and secondary structures of RNA. We compute precise asymptotics for the number of different shape representations of size n and for the number of different shapes showing up when abstracting from secondary structures of size n under a combinatorial point of view. A more realistic model taking primary structures into account remains an open challenge. We give some arguments why the present techniques cannot be applied in this case.     

Thrombin stimulates Na+-H+ exchange across the human platelet plasma membrane

We have investigated the release of protons from thrombin-stimulated platelets. Addition of thrombin to suspensions of washed platelets resulted in fast liberation of H+. In the presence of 0.1 mM amiloride, a potent inhibitor of the Na+/H+ transport system, the amount of protons liberated was decreased by about 50%, and was further reduced to about 15% by 1 mM amiloride. Similar inhibition of H+ release was observed after Na+ in the incubating medium had been replaced by choline. We conclude that one of the earliest events in thrombin-stimulated platelets consists of the activation of an Na+/H+ countertransport, which leads to an increase in intracellular pH.     

Combination of neutron activation analysis,tracer techniques,and biochemical methods in the investigation of selenium metabolism

Biological Trace Element Research - In several studies on rats, the metabolism of selenium was investigated. The quantitative determination of the element was carried out by instrumental neutron...