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.     

Properties of a nuclear protein marker of human myeloid cell differentiation

The Mr 55,000 nuclear antigen present in the human promyelocytic cell line HL-60 is a basic protein that is extracted from nuclei or chromatin by 0.35 M NaCl. The antigen is confined to the nucleus of the interphase HL-60 cell as judged by immunocytochemical localization but disperses throughout the cell during mitosis. The antigen was not detected in leukemic cell lines with blast cell properties or in cell lines representing other lineages. Additional cell lines (ML-1, ML-2, and U937) with myeloid cell characteristics similar to those of the HL-60 cells, which also differentiate in vitro, express the antigen. The presence of antigen in normal human myeloid cells in peripheral blood and bone marrow is consistent with its proposed role in nuclear events associated with normal human myeloid cell differentiation.     

On a mechanism of cardiac electrical stability. The fractal hypothesis.

Electrical activation of the ventricles via the His-Purkinje system is represented on the body surface by a waveform with a broad range of frequency components. We speculate that this process is mediated by current flow through a fractal-like conduction network and therefore that the broadband spectrum of the depolarization waveform should be scaled as a power-law distribution. The prediction is confirmed by Fourier analysis of electrocardiographic data from healthy men. This observation suggests a new dynamical link between nonlinear (fractal) structure and nonlinear function in a stable physiologic system.     

Synthesis, intracellular processing, and signal peptide of human apolipoprotein E

Northern blotting analysis has shown apo-E mRNA synthesis by human liver, HepG2 cells, and primary cultures of human monocyte macrophages but not by the macrophage-like cell line U937 and normal or transformed human fibroblasts. Cell-free translation has shown that the primary translation product of apo-E consists of one major and one minor isoprotein of apparent Mr = 28,500 and isoelectric points 6.20 and 6.02, respectively. These isoproteins differ by +1 and 0 charges from apo-E3 and have been designated preapo-E. Co-translational treatment of mRNA with dog pancreatic membranes converts both preapo-E isoproteins to a form which is undistinguishable by two-dimensional gel electrophoresis from plasma apo-E3. The isolation and nucleotide sequence analysis of a full length apo-E cDNA clone has shown that preapo-E contains an 18-amino acid NH2-terminal signal peptide compared to plasma apo-E. The signal peptide sequence is: MetLysValLeuTrpAlaAlaLeuLeuValThrPheLeuAlaGlyCysGlnAla. Comparison of co-translationally modified apo-E with intracellular, secreted, and plasma forms indicates that after the intracellular cleavage of the signal peptide, the protein is glycosylated with carbohydrate chains containing sialic acid, secreted as sialoapo-E (apo-Es), and subsequently desialated in plasma. These findings demonstrate that apo-E is synthesized as preprotein and undergoes intracellular proteolysis and glycosylation and extracellular desialation to attain the major asialoapo-E isoprotein form observed in plasma.     

Structural organization of the normal and anoxic heart of Scyllium stellare

Summary The general and ultrastructural organization of the heart of the elasmobranch, Scyllium stellare, was studied in normal and in anoxic animals. The rich coronary supply was revealed three-dimensionally by the use of corrosion casts, showing a thebesian system of coronary arterioles and capillaries in the thin, outer compact layer as well as in the predominant, inner spongy layer of trabeculae.Only the sinus venosus received a neuronal input of large bundles of granule-containing axons terminating at fenestrated regions of the endocardium and suggesting a neurohormonal function.A simple, tubular sarcoplasmic reticulum with flattened junctional cisternae was present in myocardial cells of 1–5 m diameter, which contained one or two bundles of myofibrils. The latter were closely apposed to the inner aspect of the plasmalemma. Mitochondria were located centrally in the cells, which were joined by unfolded desmosomes involving Z-band material.Long periods of anoxia were tolerated without loss of heart function, but at the expense of cytoplasmic glycogen. Lipid granules were abundant in all layers and chambers, notably in animals prepared in the summer. The lipid granules displayed a marked increase in electron density when the heart was incubated in a buffered oxalate solution prior to fixation. A glycogen-sparing effect of the lipids during anoxia was observed.