Chemical and biological evaluation of endotoxin contamination on natural rubber latex products

Abstract

Relationship between pyrogenicity and bacterial endotoxin contamination on latex products was demonstrated by chemical analysis and biological assays. In commercially available latex products' surveillance, water extracts prepared from one surgical glove and two silicone elastomer-coated Foley catheters sterilized by gamma-irradiation were obviously pyrogenic in rabbits. The induced fever was monophasic at low dose of the pyrogenic extracts and biphasic at high dose. These extracts exhibited limulus amebocyte lysate gelation activity, and induced inflammatory cytokine (interleukin-1, interleukin-6, and tumor necrosis factor-alpha) production from MM6-CA8 human monocytoid cells. These biological properties, including pyrogenicity, completely disappeared by treating the pyrogenic extracts with endotoxin-adsorbent affinity column. Limulus amebocyte lysate activity and cytokine production from MM6-CA8 cells induced by the extracts were significantly decreased by endotoxin inhibitors, an active fragment peptide of an 18-kDa cationic antimicrobial protein and a synthetic lipid A B464 analogue. Furthermore, very small amounts of 2-keto-3-deoxyoctonate and 3-hydroxy fatty acid, which are common constituents of bacterial endotoxins, were detected by gas chromatography-mass spectrometry analysis of the pyrogenic extracts. These findings clearly showed that the pyrogenicity found in these latex products originated from endotoxins contaminating the products.

Removal of immune-stimulatory components from surfaces by plasma discharges

“…It has been shown that LPS is only extractable to a certain extent, while residuals stick on the surface and thus cannot be detected by the pyrogen-testing procedures mentioned above. [11][12][13][14] Furthermore, it has also been shown that the inflammatory capacity of some pyrogens can increase when they are bound on surfaces compared to the cytokine release evoked by pyrogens in the liquid state; 15 consequently, this can lead to the underestimation of possible risks when testing eluates.…”

An in vitro pyrogen safety test for immune-stimulating components on surfaces

“…fever inducing substances. This means that a device may be sterile but still pyrogenic, as it has been shown in several studies [12][13][14].…”

A biological study establishing the endotoxin limit of biomaterials for bone regeneration in cranial and femoral implantation of rats

“…Heat‐sacrificed bacterial cells were collected by centrifugation (7000 g, 15 min) and washed three times with distilled water followed by sequential extraction with ethanol, acetone, and diethyl ether to dehydrate the cells. Endotoxin was extracted from the dried cells of the E. coli O3:K2a,K2b:H3 ATCC strain by the phenol‐water method, and purified by repeated ultracentrifugation after deoxyribonuclease and ribonuclease treatments . The endotoxin activities of the purified endotoxin and the dried E. coli 0111 cells were 27.5 and 0.159 EU/ng, respectively.…”

“…Endotoxin was extracted from the dried cells of the E. coli O3:K2a,K2b:H3 ATCC strain by the phenol-water method, 18 and purified by repeated ultracentrifugation after deoxyribonuclease and ribonuclease treatments. 19 The endotoxin activities of the purified endotoxin and the dried E. coli 0111 cells were 27.5 and 0.159 EU/ng, respectively. Endotoxin was present as a contaminant in the dried S. aureus cells at 0.48 EU/mg.…”