The separation of timothy pollen extract by two-dimensional immunoblotting revealed microheterogeneity of the major allergens PhI p I and PhI p V. There was not only a diversity in size, 38 and 32 kDa for PhI p V and 37, 35, and 33 kDa for PhI p I, but also a separation into proteins of identical sizes but different pIs. Since former studies on the protein structure by amino acid analysis and N-terminal microsequencing did not reveal any differences, we examined other possibilities that might cause microheterogeneity. In allergens belonging to the PhI p I group, the variability in pI can be due to the carbohydrate structure and to the fact that charges are hidden in the interior of the protein, as shown by varying concentrations of urea. On the other hand we were not able to detect any such reasons for the existence of PhI p V isoallergens. Thus, we assume that they are stable conformational isomers of the proteins (allomorphism) or that there are only slight variations in the internal sequences of these proteins (polymorphism) causing distinct pIs.

Allergens↗

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Trace elements in shellfish on the Danish market.

Different kinds of shellfish have been investigated for their contents of the trace elements cadmium, lead, mercury, nickel, chromium, arsenic and selenium. The investigation included shrimps, mussels, lobster, langoustine, crayfish, crab claws and oyster. None of the Danish action levels for cadmium, lead and mercury respectively were exceeded, but the highest concentration of lead was very close to the Danish action levels. Shellfish do not contribute significantly to the intake of the trace elements investigated.

Denmark↗

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Clostridial myonecrosis, hepatitis, and nephritis in a llama with vegetative endocarditis.

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Animals↗

PubMedDate not supplied

Implications of the grass group I allergens on the sensitization and provocation process.

Grass pollen allergens of group I are particularly important because of their high IgE prevalence and occurrence in all grass species. Four independent IgE-binding regions and one continous epitope were identified. The posttranslational modifications on the molecule increased allergenicity. Phl p 1 is a cysteine protease, as determined by specific substrates, inhibitors and consensus sequence motifs. In analogy to other allergens and/or proteases, we deduce that Phl p 1 might enhance the permeability of the epithelium, influence T helper cells to bias Th2, and increase the IgE production of plasma cells. Thus, the group I allergens seem to be the crucial components in a pollen extract which can mediate sensitization and enhance the triggering of symptoms leading to the persistence of a grass pollen allergy.

Allergens↗

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A new model for assessing proteolysis in the intact mouse lens in organ culture.

PURPOSE: To develop a new method to investigate proteolysis in the intact lens in organ culture. METHODS: Intact mouse lenses were assayed at regular intervals for proteolytic activity using fluorogenic peptide substrates +/- addition of ionomycin. Specific inhibitors were used to determine the activity of calpains, the proteasome and acid lysosomal enzymes. RESULTS: Significant levels of proteolytic activity were present in the intact lens. Proteolysis was stimulated by ionomycin. Preincubation with an inhibitor to the proteasome significantly decreased proteolysis whereas inhibitors of calpain and acid lysosomal enzymes did not. CONCLUSION: This study indicates that in the intact mouse lens in culture, the proteasome is an important protease. Its activity is at least partially regulated by calcium.

Animals↗

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Molecular characterization of timothy grass pollen group V allergens.

Phl p V is the dominant allergen of timothy grass (Phleum pratense) with two isoforms having the apparent molecular weights of 38 (Phl p Va) and 32 kD (Phl p Vb) under Western blot conditions. Two-dimensional electrophoresis/immunoblotting reveals that each isoform is split into at least four isoallergens. Structural differences in the isoforms are shown by N-terminal sequencing (only 60% identity), by reaction patterns of monoclonal antibodies and, more convincingly, by enzymic degradation of purified isoforms followed by immunologic fingerprinting. These findings are confirmed by the deduced primary protein structure of cloned Phl p Va and Phl p Vb. Experiments with IgE--affinity-purified by immobilized recombinant allergens or their fragments--reveal identical epitopes and at least one different epitope between the isoforms. Furthermore, on Phl p Va we can localize different IgE-reactive epitopes at the C terminus as well as the N terminus. By probing serum from 11 patients on recombinant C- or N-terminal fragments, an individual reaction pattern was found. Testing the histamine liberation potency of the fragments, we found the N-terminal fragment of Phl p Va to be superior to that of the C-terminal fragment or the whole molecule. These results give insights into the variability of allergens, the individuality of human reaction patterns to epitopes and the alteration of allergenicity to higher or lower levels by fragmentation.

Allergens↗

PubMedDate not supplied

Grafting of nigral tissue hibernated with tirilazad mesylate and glial cell line-derived neurotrophic factor.

Transplantation of embryonic ventral mesencephalon is a potential therapy for patients with Parkinson's disease. As only around 5-10% of embryonic dopaminergic neurons survive grafting into the adult striatum, it is considered necessary to use multiple donor embryos. To increase the survival of the grafted dopaminergic neurons, the clinical transplantation program in Lund currently employs the lipid peroxidation inhibitor, tirilazad mesylate, in all solutions used during tissue storage, preparation, and transplantation. However, the difficulty in obtaining a sufficient number of donor embryos still remains an important limiting factor for the clinical application of neural transplantation. In many clinical transplantation programs, it would be a great advantage if human nigral donor tissue could be stored for at least 1 week. This study was performed in order to investigate whether storage of embryonic tissue at 4 degrees C for 8 days can be applied clinically without creating a need to increase the number of donors. We compared the survival of freshly grafted rat nigral tissue, prepared according to the clinical protocol, with tissue transplanted after hibernation. Thus, in all groups tirilazad mesylate was omnipresent. One group of rats was implanted with fresh tissue and three groups with hibernated tissue with or without addition of glial cell line-derived neurotrophic factor (GDNF) in the hibernation medium and/or the final cell suspension. Earlier studies have suggested that GDNF improves the survival of hibernated nigral transplants. We found no statistically significant difference between the groups regarding graft survival after 3 weeks. However, there was a nonsignificant trend for fewer surviving dopaminergic neurons in grafts from hibernated tissue compared to fresh controls. Furthermore, we show that the addition of GDNF to the hibernation medium and/or to the final cell suspension does not significantly increase the survival of the dopaminergic neurons.

Animals↗