The commercially available alpha-amylase from Aspergillus oryzae which is widely used as a baking additive was compared with a highly purified enzyme preparation. We used enzyme allergosorbent test (EAST), EAST inhibition, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), isoelectric focussing, immunoblotting, and N-terminal amino acid sequencing to characterize the causative allergen. Our screening comprised 89 partially selected bakers. Forty-three (48%) of them had work-related respiratory symptoms; 14 (32%) of whom were sensitized to the baking additive. Significant immunological differences could not be found between crude and purified sample with the exception that the latter one produced nearly twice as high antibody values. Iodine starch staining demonstrated that the component which was exclusively or predominantly bound by IgE antibodies of symptomatic bakers represents the active alpha-amylase. According to the International Union of Immunological Societies (IUIS) nomenclature, the term Asp o II is suggested for this important occupational allergen.

Allergens↗

PubMed1994

Localisation of thromboxane A2 receptors and the corresponding mRNAs in human eye tissue.

Thromboxane A2 (TxA2) receptors in human eye sections were identified and localised using a potent TxA2 specific agonist, 125-iodinated 5-heptenoic acid 7-[3-[3-hydroxy-4-[4-(iodo-125I) phenoxy]-1-butenyl]-7- oxabicyclo[2.2.1]hept-2-yl]-,[1S-[1a,2a,(Z),3B(1E,3S*),4a]]-C23 H29 IO5 (125I-BOP) in a binding assay. TxA2 receptors were concentrated in several specific loci within ocular tissues, including the corneal epithelium, the ciliary processes, retina, and posterior ciliary arteries. In addition, we have used the method of in situ hybridisation to observe the distribution of TxA2 receptor mRNA. The distributions of both receptor binding sites and receptor mRNAs showed a close correlation. These studies employed film autoradiography which does not permit cellular resolution. In order to obtain enhanced cellular resolution and more detailed information about the localisation of the receptors and their corresponding mRNAs, emulsion autoradiography was used after ligand binding and in situ hybridisation. This approach showed further that TxA2 receptors are mainly concentrated on non-pigmented epithelial cells of the ciliary processes, on photoreceptors within the retina, and on endothelial cells of the posterior ciliary arteries. These results may be helpful for understanding the pathophysiological effects of TxA2 in the human eye.

Adult↗

PubMed1994

Exposure of workers to a mixture of toluene and xylenes. II. Effects.

The health effects of exposure to a mixture of toluene and xylene isomers was studied on the fourth or fifth days of a working week in factories in China. The study population comprised 233 subjects (122 men and 111 women), who were exposed to the time weighted geometric mean (maximum) concentrations of toluene (3 (203) ppm) and xylenes (4 (103) ppm). For comparison, 241 non-exposed controls (116 men and 125 women) were recruited from the same regions. The prevalence of some subjective symptoms significantly increased in the exposed population, and the symptom profiles were similar to those found after exposure to toluene or xylenes alone. Haematology and serum biochemistry did not show notable changes. It seems reasonable to conclude that the effects of the toxicities of toluene and xylenes in combination are additive.

Adult↗

PubMed1994

Preload does not influence nonmechanical O2 consumption in isolated rabbit heart.

Myocardial energy consumption for nonmechanical activity (excitation-contraction coupling) has been shown to be length dependent in isolated muscle studies but no more than minimally affected by preload in the whole heart. However, unloaded O2 consumption (VO2, which is used to estimate nonmechanical VO2 in whole heart) may not be accurate for quantifying nonmechanical energy consumption, because it contains VO2 for residual cross-bridge cycling. To more accurately determine the influence of left ventricular (LV) diastolic volume on nonmechanical VO2 in whole heart, we employed a new method for quantifying nonmechanical VO2, using the drug 2,3-butanedione monoxime (BDM). We measured VO2 and force-time integral during infusion of BDM (< or = 5 mM) at high (VH) and low LV volumes (VL) in 16 excised isovolumically contracting red blood cell-perfused rabbit ventricles. LV end-diastolic pressure was 9.7 +/- 4.6 and 3.8 +/- 2.8 (SD) mmHg at VH and VL, respectively. Nonmechanical VO2, estimated as the VO2-axis intercept of the linear VO2-force-time integral relation obtained during BDM infusion, did not differ significantly between VH and VL (0.0137 +/- 0.0083 and 0.0132 +/- 0.0090 ml O2.beat-1 x 100 gLV-1, P = 0.702). A multiple linear regression analysis for the pooled data confirmed this finding (P = 0.361). We conclude that, in the rabbit heart, LV diastolic volume does not importantly affect nonmechanical energy consumption over a physiological range of LV end-diastolic pressure. This indicates that length-dependent activation does not have an energetic cost in whole rabbit heart and suggests that its predominant mechanism is increased Ca2+ affinity for the contractile proteins.

Animals↗

PubMed1994

Expression of high density lipoprotein-binding protein messenger ribonucleic acid in the rat ovary and its regulation by gonadotropin.

The presence of high density lipoprotein-binding protein (HBP) mRNA in rat ovarian cells and its possible regulation by gonadotropin were examined in this study. RNA, isolated from pseudopregnant rat ovaries, was amplified by reverse transcriptase-polymerase chain reaction (PCR) with HBP-specific oligonucleotide primers. A distinct and prominent 576-basepair PCR product was generated. Sequence analysis revealed that the sequence homology of the PCR product and the corresponding human HBP cDNA sequence was greater than 90%. Using Northern blot analysis, we identified two species of HBP mRNA transcripts in the ovarian cells (i.e. a major one of 4.5 kilobases and a minor one of 6.0 kilobases). Cellular localization of HBP mRNA in the ovary was determined by in situ hybridization analysis. Prominent specific hybridization of the labeled antisense probe was observed in all cell types of the follicles and corpora lutea, whereas little hybridization was observed in the stroma and the connective tissues separating corpora lutea and follicles. As hCG has been shown to induce high density lipoprotein-binding activity in the rat ovary, we examined the possible regulation of ovarian HBP mRNA by this hormone. Administration of hCG caused a significant time-dependent increase in the steady state levels of HBP mRNA. The induction of HBP mRNA levels by hCG is specific for the ovary, as pretreatment with hCG had no effect on the HBP mRNA levels of the liver, heart, lung, or kidney. The present study, for the first time, shows conclusively the presence of HBP mRNA in the rat ovary and its induction by hCG, implicating a physiological role for HBP in the ovary.

Animals↗

PubMed1994

Atomic force microscopy of dimyristoylphosphatidylcholine membranes.

We have observed the surface images of dimyristoylphosphatidylcholine (DMPC) monolayer and DMPC vesicles with an atomic force microscope (AFM). It was confirmed that the lattice structure of polar head groups of DMPC molecules in a Langmuir-Blodgett monolayer is similar to those of large unilamellar DMPC vesicles. AFM images of small unilamellar vesicles of DMPC showed larger lattice structures than those of the monolayer, reflecting differences of molecular packing in these membranes.

Dimyristoylphosphatidylcholine↗