Contact sensitization to organosilane solution in glass filament production
Glass filaments have been commercially produced since the 1930s, and are now mainly used for reinforcing plastics, paper, textiles, floorings, boats, and bituminous products, and rendering appliances like pipes and tanks corrosion-resistant. During production, filaments are coated with a water dispersion of epoxy resins, polyester resins, silane compounds, emulsifiers, lubricants, surfactants and antistatic agents. Various silanes are used as bonding agents between glass and resin in the final product. 2 studies have recently reported sensitization to silanes (1, 2).
Gas chromatographic determination of some alkoxysilanes for use in occupational exposure assessment.
The manufacture and application of organosilicon compounds, especially silanes, have increased dramatically during recent decades. This has led to an increase in the number of exposed workers in different areas of industry. Therefore, there is an urgent need for an analytical method which can assess exposure to these compounds. A capillary column gas chromatographic (GC) method was developed for detecting 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane and 3-aminopropyltriethoxysilane. The silanes diluted in heptane were analysed by GC using flame ionisation detection. Gas chromatography-mass spectrometry was used to confirm the identity of the GC peaks. The analytical range of the method varied from 1 or 5 micrograms ml-1 to 500 micrograms ml-1 depending on the silane being studied. The detection limits were 1 microgram ml-1 for 3-methacryloxypropyltrimethoxysilane and 3-glycidoxypropyltrimethoxysilane and 5 micrograms ml-1 for 3-aminopropyltriethoxysilane. The mean recovery of silanes tested with patch samples was > 95% for all of the silanes. The repeatability of the patch sample method for silanes varied from 6.5 to 10.1%. This new GC method allows the simultaneous determination of three organosilicon compounds for occupational exposure assessment.
Allergy to penicillin with good tolerance to other penicillins; study of the incidence in subjects allergic to betalactams
Two hundred and eighty‐eight subjects with a history of allergy to penicillin were studied for objective proof of their allergy. On the basis of skin tests, specific IgE antibody measurements and direct challenge tests, 64 patients (22%) were shown objectively to be allergic to one or more penicillins. The following tests were carried out: skin tests to benzyl‐penicilloyl poly‐L‐lysine (BPO‐PLL), minor determinant mixture (MDM), amoxycillin (AX) and ampicillin (AMP), in‐vitro IgE antibody measurement to benzyl‐penicilloyl (BPO) and AX and challenge with benzylpenicillin (BP), phenoxymethyl‐penicillin (PV) and amoxycillin. Forty‐four cases were found to respond to benzyl or phenoxymethyl‐penicillin, however, 20 were shown to be sensitive to amoxycillin and unresponsive to tests with other penicillins. The contribution that any individual test gave for establishing the diagnosis was 21·8% for skin testing with BPO‐PLL, 9·3% with MDM and 12·5% with AX, Nine point three per cent were RAST positive to BPO and 1·5% to AX; 7·8% developed a positive response after challenge to BP, 7·8% to PV and 14% to AX. In 16% of the 64 positive cases more than one test was found to be positive. The challenge tests suggested that not all the penicillin‐sensitive subjects had IgE‐mediated reactions implying other immunological mechanisms. These results clearly demonstrate the importance of side chain‐specific diagnostic reagents and challenge tests. Thirty‐one per cent of the positive group or 6·9% of the total group would have been missed in this study using benzyl or phenoxymethyl‐penicillin diagnostic reagents alone.