Michio Sato

Plant defense–related enzymes as latex antigens☆☆☆★★★♢

BACKGROUND Latex allergy is an increasing hazard to people who frequently come into contact with latex products. Of interest concerning this immediate-type allergy is the cross-reactivity to various vegetable foods and pollen. Despite its high prevalence, no adequate explanation has been provided for the cross-reactive antigens. OBJECTIVE We have hypothesized that a series of plant defense-related proteins act as latex allergens, as well as vegetable food allergens. To evaluate this hypothesis, hydrolytic enzymes that are very likely to take on defensive roles in rubber trees were examined for their antigenicity. METHODS By applying chromatographic procedures, defense-related enzymes were separated from nonammoniated latex (NAL). Their antigenicity was examined by immunoblotting and ELISA with sera containing IgE antibodies to crude latex proteins. RESULTS Three kinds of hydrolytic enzymes (basic beta-1,3-glucanases [35, 36.5, and 38 kd], a basic chitinase/lysozyme [29.5 kd], and an acidic esterase [44 kd]) were separated from NAL. They were recognized by IgE antibodies from a significant number of patients allergic to latex. The basic beta-1,3-glucanases and the acidic esterase were also strongly recognized by IgE antibodies from several atopic subjects who were allergic to various vegetable foods rather than latex products. CONCLUSION It was ascertained that the three defense-related enzymes separated from NAL constituted part of the latex antigens. Taking together the well-known serologic or immunologic relationships and amino acid sequence similarities of defense-related proteins coming from phylogenetically distant plant species, we can suspect their universal antigenicity and cross-reactivity.

One of the rubber latex allergens is a lysozyme

BACKGROUND Type I hypersensitivity reactions caused by latex products are ascribed to proteins eluted from them, but little is known about the properties of these allergenic proteins. The reason for the cross-reaction between rubber latex and fruits is also not known. We have speculated that a series of defense-related proteins in plants is a cause of latex allergy and the cross reaction. OBJECTIVE To verify our hypothesis, we selected a lysozyme as a representative defense-related protein and examined its relationship to latex allergy. METHODS Lysozymes eluted from latex gloves were detected with a cell-suspension clearing test. A chromatographically separated lysozyme was investigated for its physicochemical and enzymatic properties and allergenicity. RESULTS Lysozyme activity was detected in extracts from ammoniated latex and latex gloves. We separated a lysozyme (27 kd; isoelectric point, 9.5) using cation-exchange and gel filtration chromatography. This lysozyme was enzymatically very similar to fruit lysozymes and was demonstrated to be an allergen. CONCLUSIONS One of the rubber latex allergens is a lysozyme that has similarities to fruit lysozymes. This suggests the relevance of defense-related proteins to latex allergy and the cross reaction.

Isolation and identification of metabolites of 2-ethylhexyl diphenyl phosphate in rats

The metabolic fate of 2-ethylhexyl diphenyl phosphate (EHDPP) was studied in male rats. Orally administered 14C-EHDPP was rapidly absorbed and about 80% of the radioactivity was excreted in the urine and feces in the first 24 h. By 7 days, 48% and 52% of the radioactivity was recovered in urine and feces, respectively. Since biliary excretion was low (6% for 2 days), urine seems to be the major excretion route of EHDPP. Radioactivity was widely distributed in all tissues examined. At 2 h, the concentration was relatively high in blood, liver kidney and adipose tissue. The elimination of radioactivity from adipose tissue and liver was somewhat delayed, but almost all the radioactivity was eliminated by 7 days. The major metabolites in the urine were diphenyl phosphate (DPP) and phenol. p-Hydroxyphenyl phenyl phosphate (OH-DPP) and monophenyl phosphate (MPP) were also identified as minor metabolites.

ONE OF THE RUBBER LATEX ALLERGENS HAS LYSOZYME ACTIVITY

Correspondence to: Takeshi Yagami, MS, Division of Medical Devices, National Institute of Health Sciences, Kamiyoga 118-1, Setagaya-ku, Tokyo 158 (Japan) Dear Sir, Recently type I hypersensitivity reactions caused by rubber latex gloves have frequently been reported, and some proteins eluted from rubber gloves are considered to be responsible for this allergy [1]. Although the molecular weights of these allergenic proteins have been determined by several groups, the detailed properties of them have not been clarified yet. On the other hand, it was reported that rubber latex allergy was occasionally associated with allergy to fruits such as banana, avocado, fig, and passion-fruit [2]. The cross-reactivity between rubber latex and these fruits implies the presence of common antigens or antigenic determinants, but any reasonable explanation has not been presented so far because of phylogenetical dissimilarity between rubber tree (Hevea brasiliensis) and these fruits. We report here that one of the allergenic proteins in rubber latex gloves has lysozyme (mucopeptide Λ1⁄8cetylmuramoylhy-drolase, EC 3.2.1.17) activity. The presence of this protein may be accountable for the cross-reactivity between rubber latex and fruits. There are some reports describing the lysozyme activity of avocado, papaya [3], fig [4], and also rubber tree latex [5]. We focused our attention on this enzyme activity, and examined the extracts from ammoniated rubber latex, surgical gloves (Triflex; Baxter, USA), and household gloves (Dunlop Home Products, Japan) by means of a cell suspension clearing test using Micrococcus lysodeikticus cell walls [3]. All of the three extracts exhibited strong clearing activity, i.e., lysozyme activity. The protein profiles of these extracts in sodium dodecyl sulfate-polyacrylamide gel electrophoresis were different, but they had a common strong band at 27 kD. We isolated a protein having lysozyme activity by ion-exchange chromatography, and gel filtration chromatography then confirmed that the lysozyme activity was mostly ascribed to the 27-kD protein. This protein showed its maximum lysozyme activity at pH 4.4 and 70 °C in 0.03 ionic strength buffer. Moreover, the activity was effectively inhibited by histamine (60% inhibition at 0.02 M), but not by Λ1⁄2ce-tyl-D-glucosamine (20% inhibition at 0.4 M). These features coincide with those of papaya, fig, and other plant lysozymes. In point of al-lergenicity, the glove extracts and the isolated lysozyme were submitted to immunoblotting with the serum of a 51-year-old housewife. She had developed generalized wheal after wearing the household gloves and exhibited strongly positive reactions in prick test to the aqueous extracts of the ammoniated rubber latex and the two brands of gloves (Triflex, Dunlop). The IgE antibodies

Excretion, distribution and metabolism of 1,2,4-trichlorobenzene in rats

Abstract1,2,4-Trichlorobenzene (TCB) labeled with C-14 was given perorally to rats at a dosage of 50 mg/kg for excretion and distribution studies.About 66% and 17% of the oral dose was excreted in the urine and feces, respectively, within 7 days. Trapped radioactivity in the expired air amounted to 2.1% of the dose, but production of labeled carbon dioxide was negligible. Tissue residues were evenly distributed throughout the organs and tissues examined, except for the adipose tissue which consistently had a little higher concentration.The urinary, fecal and expiratory metabolites were identified. Free 2,4,5- and 2,3,5-trichlorophenol (TCP) and their conjugates were mainly detected in the urine. 5- or 6-Sulfhydryl, methylthio, methylsulfoxide and methylsulfone derivatives of TCB were also detected as minor metabolites. Dichlorobenzenes and unchanged TCB were confirmed in the expired air. Reductive dechlroination seems to be catalysed by intestinal microflora enzymes.

Esterase from ammoniated latex: Biochemical characterization and antigenicity

Latex allergy is a recently increasing hazard to people who are repeatedly in contact with Latex products. Notably, with this allergy, cross‐reactivity to vegetable foods and pollen is frequently observed. It is postulated that pathogenesis‐ or, rather, defence‐related proteins induced in rubber trees are responsible for the Latex allergy and the cross‐reactivity. To evaluate this hypothesis, an esterase was selected as one of the probable defence‐related proteins in rubber Latex and its involvement in Latex allergy was investigated. The biochemical properties of a chromatographically purified esterase from ammoniated Latex were compared with those of esterases (hevains) previously purified from rubber Latex. The antigenicity of the esterase was examined by immunoblotting using sera from Latex‐allergic patients. The purified esterase (of molecular weight 80 kDa) dissociated into subunits under denaturing conditions and shared biochemical properties with hevain 1 from lutoids. The esterase was recognized b...

Direct evaluation of fatigue property of ultra-high molecular weight polyethylene components of retrieved knee implants using small specimens

Ultra-high molecular weight polyethylene (UHMWPE) has been widely used as a bearing surface of joint implants. Since wear of UHMWPE component has been the primal cause of implant failure, crosslinking of UHMWPE is now widely used to improve its wear property. On the other hand, crosslinking degrades its fatigue property and increase of fatigue related failure, such as delamination, is possible. However, the relationship between degraded fatigue property and implant failure is not clear, primarily because the fatigue properties of failed and retrieved UHMWPE components are not known. In this study, we propose a new test method to evaluate the fatigue property of retrieved UHMWPE components or final products using small specimens. First, the effects of test conditions were investigated using virgin UHMWPE. Then, tests were repeated using specimens from UHMWPE components of retrieved knee implants. The fatigue properties of virgin and retrieved UHMWPE were suc- cessfully evaluated by the new test method and a relationship was found among the extent of oxidation, the fatigue property, and occurrence of delamination. This result suggested that evaluation of fatigue property of UHMWPE component can predict the occurrence of fatigue related implant failure during operation in vivo.