Seasonal variation in food allergy to apple

The aim of the study was to investigate the possibility of a seasonal variation in reactivity to apples in 27 birch pollen allergic patients. Before and during the birch pollen season 1998, the patients were subjected to double-blind, placebo-controlled food challenges (DBPCFCs) with grated fresh Golden Delicious apple followed by an open food challenge with whole fresh apple. The clinical reactions elicited during the challenges were evaluated both by the patients and the investigators. Moreover, the skin reactivity and the in vitro reactivity to apple were evaluated by skin prick test (SPT), leukocyte histamine release (HR), measurement of specific IgE, and immunoblotting experiments. The sensitivity of the DBPCFC, when compared with the result of the open challenge, was 0.74 (14/19) before the season and 0.80 (16/20) during the season. None of the patients reacted to the blinded challenge without a subsequent reaction to the open challenge. One placebo reaction was registered both before and in season, but not in the same patient. The patient scores of the first positive challenges, and the maximal scores of each combined blinded and open challenge session, were significantly increased during the pollen season (P<0.05). The scores of the open challenge were significantly higher than the scores of the DBPCFC both before the season and during the in-season challenges (P<0.05). Specific IgE against Golden Delicious increased during season (P<0.05), while neither SPT, HR, nor immunoblotting experiments could confirm an increase in reactivity. In conclusion, the results of the oral challenge tests indicated an increase in clinical reactivity to apples during the birch pollen season in birch pollen allergic individuals.     

Purification of an extracellular cellulose-binding endoglucanase of Cellulomonas sp. ATCC 21399 by affinity chromatography on H3PO4-swollen cellulose

A cellulose-binding endoglucanase (endoglucanase A) of Cellulomonas sp. ATCC 21399 was purified to immunological homogeneity by affinity chromatography ob H(3)PO(4)-swollen cellulose. This method of purification turned out to be an easy and very gentle method for obtaining a high yield of cellulose-binding endoglucanase. The purified enzyme was immunologically homogeneous but appeared heterogeneous when analyzed by denaturing polyacrylamide gel electrophoresis. In addition to the cellulose-binding of endoglucanase A, the enzyme also had a strong affinity for Concanavaline A, indicating that the enzyme was glycosylated. Purified endoglucanase A showed an endo mode of action on carboxymethylcellulose. The enzyme could hydrolyze microcrystalline cellulose when acting alone, and the enzyme had a high specific activity on H(3)PO(4)-swollen cellulose.     

Regeneration of plants from hypocotyl protoplasts of rapessed (Brassica napus L. var. oleifera) cultivars

Protoplast cultures were prepared from hypocotyls of ten spring rapeseed cultivars. Protoplasts from all genotypes tested formed calli, and shoots were regenerated from calli of nine of the genotypes at frequencies varying from 15 to 76%. The regenerating cultivars fell into a high regenerating group (>60% and a low regenerating group <25%).     

Purification and properties of Saccharomyces cerevisiae acetolactate synthase from recombinant Escherichia coli

The yeast ilv2 gene, encoding acetolactate synthase, was subcloned in an Escherichia coli expression vector. Although a major part of the acetolactate synthase synthesized by E. coli cells harbouring this vector was packaged into protein inclusion bodies, we used these recombinant E. coli cells to produce large quantities of the yeast enzyme. The yeast acetolactate synthase was purified to homogeneity using first streptomycin and ammonium sulfate precipitations, followed by T-gel thiophilic interaction, Sephacryl S-300 gel filtration, Mono Q anion exchange, and Superose 12 gel filtration chromatography. SDS/PAGE and gel filtration of the purified enzyme showed that it is a dimer composed of two subunits, each with the molecular mass of 75 kDa. The purified yeast acetolactate synthase was further characterized with respect to pH optimum, dependence of the substrate, pyruvate, and requirements of the cofactors, thiamin diphosphate, Mg2+, and FAD.     

The effect of ranitidine on cellular immunity in patients with multiple myeloma

Summary Multiple myeloma is characterized by an increased susceptibility to infections and to other malignancies. In a double-blind, placebo-controlled study the potential impact of immunomodulation by ranitidine was studied in 20 patients with multiple myeloma. Three patients were untreated, while 17 after previous cytotoxic therapy were in a stable phase of their disease. All were without clinical signs of infections and at that time had not been treated with other immunomodulating agents. The patients were randomized to oral ranitidine 300 mg twice a day for 21 days or placebo, and several immunological parameters related to multiple myeloma were studied. The blood monocyte chemotactic response was improved in patients treated with ranitidine, and superoxide anion production increased from 2.02 nmol/min to 3.86 nmol/min (median values), while it was unchanged in patients given placebo (2.19–2.25 nmol/min) (P <0.005 between groups). Among ranitidine-treated patients spontaneous NK cell activity was unchanged, while in vitro interleukin-2- and interferon--stimulated NK cell activity decreased (P <0.03, respectively). As production of oxygen radicals constitutes an important mechanism of monocyte killing activity against microorganisms and probably against malignant cells, it is suggested that ranitidine may be of beneficial impact in the treatment of multiple myeloma.     

In vivo genetic engineering: homologous recombination as a tool for plasmid construction

This paper describes a novel method for creating exact DNA fusions between any two points in a plasmid carried in Bacillus subtilis. It exploits the homologous in vivo recombination between directly repeated sequences that can be established by insertion of a synthetic oligodeoxyribonucleotide. The method was used to enhance the productivity in B. subtilis of a cloned alpha-amylase (Amy)-encoding gene originating from Bacillus stearothermophilus. Thus, an exact fusion between nucleotide sequences encoding the expression signals, including the signal peptide, of a Bacillus licheniformis Amy-encoding gene and the mature Amy of B. stearothermophilus, was created. The resulting hybrid translational product was processed correctly in B. subtilis during secretion, giving rise to an Amy identical to the mature Amy secreted by B. stearothermophilus.     

The codon 408 mutation associated with haplotype 2 is predominant in Polish families with phenylketonuria

Summary The incidence of phenylketonuria (PKU) in the western part of Poland is 1 in 5000 live births. Restriction fragment length polymorphism (RFLP) haplotypes at the phenylalanine hydroxylase locus have been analysed in 46 Polish families with PKU. Among 43 fully-informative families 16 RFLP haplotypes were identified. Haplotype 2 is the most frequently (62%) associated with Polish PKU alleles, and the codon 408 mutation is in complete linkage disequilibrium with this haplotype in Poland. This finding is in agreement with observations in other eastern European countries (German Democratic Republic, Czechoslovakia, and Hungary) and in contrast to the genotype distribution observed in western European countries. The present observation suggests the spread of classical PKU, due to the codon 408 mutation associated with haplotype 2, from east to west in European populations. Perhaps more important for genetic counselling, 62% of all PKU chromosomes in the Polish population can now be detected using only one mutantspecific oligonucleotide probe.