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287. Non-sensitization by formaldehyde-treated materials
300
PROCESSING AND PACKAGING CONTAMINANTS
aerylonitrile (I), potassium cyanide (II) or acetone cyanohydrin (III). A clear distinction was shown in these experiments between the effects of I, II and III. The rate of formation of methaemoglobin-CN complex in animals killed by the median lethal dose of I was lower than in those which survived comparable doses of II, and much lower than in those that died. Mortality in animals given I was also shown to be independent of the amount of methaemoglobin-CN complex. These observations demonstrate that the toxic action of I is not related to the amount of CN formed as a result of decomposition. I is a reactive compound and it is reasonable to suppose that its toxic effects arise from the cyanoethylation by I of biologically important compounds. Magos, L. (1962). A study of acrylonitrile poisoning in relation to methaemogiobin-CN complex formation. Brit. J. industr. Med. 19, 283. 285. Effect of teflon in the rat bladder In surgery teflon has been used experimentally as a substitute for vessels, tubes and even organs in recent years. It was therefore of interest to determine whether this material could be used to form substitutes for various parts of the urinary tract. Vermeulen (J. Urol. 1954, 72, 761) however showed that foreign bodies introduced into the rat bladder precipitated the formation of bladder stones. For example zinc did so invariably and polyethylene only gave rise to stone formation in the presence of urinary infection. In the present study teflon was shown to behave in a similar fashion to polyethylene. As infection would almost always be present in patients requiring artificial substitutes for parts of the urinary tract, the use of teflon for this purpose could not be entertained. Dean, C. M. & Miller, G. M. (1962). Effect of teflon in the urinary bladder of the rat. 3". UroL 88, 624. 286. Identification of polycyclic hydrocarbons in mineral oils Microcrystalline waxes differ from the paraffins in chemical composition and in the fact that they contain varying amounts ofnaphthene hydrocarbons (Kroner, Seifen-Ole 1954, 80, 717). As well as being employed in the preparation of wrapping materials, paraffins and microcrystalline waxes are permitted components of chewing gum under the terms of the German Chewing Gum Order of 19 December 1959. As such they must conform with the requirements of an ultra-violet fluorescence test designed to detect carcinogenic hydrocarbons, but the test does not of course differentiate between carcinogenic and non-carcinogenic hydrocarbons. The present paper describes a paper chromatographic procedure for the separation and identification of polycyclic hydrocarbons present in paraffins and microcrystalline waxes. The technique involves extraction by nitromethane of the hydrocarbons from a solution of wax or paraffin in cyclohexanol. After removal of the nitromethane the residue is placed upon a disc of kieselgel paper impregnated with dimethyl formamide. Development is effected with a 3:1 mixture of methylcyclohexane saturated with dimethylformamide and cyclohexane. Helberg, D. (1962). Papierchromatographischer Nachweis von polycyclischen Kohlenwasserstoffen in Paraffinen und mikrokristallinen Wachsen. Dtsch. LebensmittRdsch. 58, 321. 287. Non-sensitization by formaldehyde-treated materials Formaldehyde (I) resins consisting of urea-, melamine- and phenol-I are used to confer crease-resistant and water-repellant properties on textiles and to add 'wet strength' to paper. Thorough washing of treated textiles after curing is essential if the presence of an excess of free I is to be avoided. Numerous cases of dermatitis, alleged to have been caused
PROCESSING AND PACKAGING CONTAMINANTS
301
by free I in textiles, have been reported in European countries. Similar reports, however, have not been forthcoming from the U.S.A. and to explain this discrepancy the authors set out to test U.S. textiles for dermatitic activity, assaying free I by the chromotropic acid method. Samples of textiles, stated to have a I content of 0.03-0.075 %, a paper towel and a facial tissue were applied to the skirt of 20 patients who previously reacted positively to 2-5 % I in routine patch tests. No signs of dermatitis were observed in these tests, nor in the same individuals wearing I-treated textiles. Hovding (Acta derm.- veneriol., Stokh. 1959, 39, 357) believed that textile-induced dermatitis was due to an excessive concentration of free I, shown by him to be present in Scandinavian finished fabrics. There is a further factor which enters into the situation, namely the widespread use of I as an anti-perspirant in Europe but not in the U.S.A. This may well be the manner in which dermatitis starts, to develop later into 'textile eczema'. Fisher, A. A., Kanof, N. B. & Biondi, Ella M. (1962). Free formaldehyde in textiles and paper. Arch. Derm. 86, 753. 288. Chromium levels in man
It is known that trivalent chromium (Cr) is involved in carbohydrate and fat metabolism and therefore appears to be an essential trace element. We have previously reported on the absence of chronic toxic effects from low levels of Cr (Cited in F.C.T. 1963, 1, 131) which may arise as a contaminant during cooking, preserving or canning. Now a comprehensive analytical survey is available of the distribution of Cr in human and animal tissues. The authors found that high concentrations of Cr were present in infant tissues~ notably in the lung, heart and kidneys. The levels diminished appreciably with age, except in the lungs. However, no accumulation of Cr was demonstrated in newborn laboratory animals. Regional differences in the Cr content of human tissues existed and it was noticeable that U.S.A. levels were well below the average, in contrast to the exceptionally high kidney Cr levels in human subjects from Bangkok and Manila. Cr levels were significantly higher in mammals other than man and this could be attributed to the greater intake of Cr in the diet of domestic and wild animals. Cr was also detected in a number of samples of potable water taken from different parts of the U.S.A. and significant differences in the Cr content, 0--7 ppb, were observed. The amount of Cr in the air varied considerably in different regions of the U S.A. and the highest Cr levels were obtained in areas of heavy industry. The average total daily intake of 30-140 tzg of Cr by man was derived from food, 30-100 /ag; water, 0--40/ag and air, 0-0.3 tzg. A very high proportion of dietary Cr was excreted in the faeces; most of what was absorbed returned to the intestine in the bile and only about 1% entered the general circulation, to be excreted in the urine. Traces might be stored, probably in an insoluble form, in the lungs. In contrast to cadmium and lead, Cr is easily eliminated from the animal body and therefore presents no toxic hazard. Schroeder, H. A., Balassa, J. J. & Tipton, Isabel H. (1962). Abnormal trace metals in m a n - Chromium. J. chron. Dis. 15, 941. 289. Molybdenum toxicology
The present study of the biological effect of molybdenum sulphate in rabbits was prompted by two facts: inorganic sulphates have been shown (Reen & Williams, Arch. Biochem. Biophys. 1956, 63, 1) to counteract poisoning by molybdenum (Mo) to some extent, and secondly rabbits have higher serum inorganic sulphate levels than man and many laboratory and farm animals. In this investigation rabbits were given 0.20-0.23 % of sodium molybdate in the diet for periods ranging between 3 and 4 weeks. In over 50 % of the test animals signs of Mo poisoning were manifest as rotation of the lower part of the foreleg
PROCESSING AND PACKAGING CONTAMINANTS
aerylonitrile (I), potassium cyanide (II) or acetone cyanohydrin (III). A clear distinction was shown in these experiments between the effects of I, II and III. The rate of formation of methaemoglobin-CN complex in animals killed by the median lethal dose of I was lower than in those which survived comparable doses of II, and much lower than in those that died. Mortality in animals given I was also shown to be independent of the amount of methaemoglobin-CN complex. These observations demonstrate that the toxic action of I is not related to the amount of CN formed as a result of decomposition. I is a reactive compound and it is reasonable to suppose that its toxic effects arise from the cyanoethylation by I of biologically important compounds. Magos, L. (1962). A study of acrylonitrile poisoning in relation to methaemogiobin-CN complex formation. Brit. J. industr. Med. 19, 283. 285. Effect of teflon in the rat bladder In surgery teflon has been used experimentally as a substitute for vessels, tubes and even organs in recent years. It was therefore of interest to determine whether this material could be used to form substitutes for various parts of the urinary tract. Vermeulen (J. Urol. 1954, 72, 761) however showed that foreign bodies introduced into the rat bladder precipitated the formation of bladder stones. For example zinc did so invariably and polyethylene only gave rise to stone formation in the presence of urinary infection. In the present study teflon was shown to behave in a similar fashion to polyethylene. As infection would almost always be present in patients requiring artificial substitutes for parts of the urinary tract, the use of teflon for this purpose could not be entertained. Dean, C. M. & Miller, G. M. (1962). Effect of teflon in the urinary bladder of the rat. 3". UroL 88, 624. 286. Identification of polycyclic hydrocarbons in mineral oils Microcrystalline waxes differ from the paraffins in chemical composition and in the fact that they contain varying amounts ofnaphthene hydrocarbons (Kroner, Seifen-Ole 1954, 80, 717). As well as being employed in the preparation of wrapping materials, paraffins and microcrystalline waxes are permitted components of chewing gum under the terms of the German Chewing Gum Order of 19 December 1959. As such they must conform with the requirements of an ultra-violet fluorescence test designed to detect carcinogenic hydrocarbons, but the test does not of course differentiate between carcinogenic and non-carcinogenic hydrocarbons. The present paper describes a paper chromatographic procedure for the separation and identification of polycyclic hydrocarbons present in paraffins and microcrystalline waxes. The technique involves extraction by nitromethane of the hydrocarbons from a solution of wax or paraffin in cyclohexanol. After removal of the nitromethane the residue is placed upon a disc of kieselgel paper impregnated with dimethyl formamide. Development is effected with a 3:1 mixture of methylcyclohexane saturated with dimethylformamide and cyclohexane. Helberg, D. (1962). Papierchromatographischer Nachweis von polycyclischen Kohlenwasserstoffen in Paraffinen und mikrokristallinen Wachsen. Dtsch. LebensmittRdsch. 58, 321. 287. Non-sensitization by formaldehyde-treated materials Formaldehyde (I) resins consisting of urea-, melamine- and phenol-I are used to confer crease-resistant and water-repellant properties on textiles and to add 'wet strength' to paper. Thorough washing of treated textiles after curing is essential if the presence of an excess of free I is to be avoided. Numerous cases of dermatitis, alleged to have been caused
PROCESSING AND PACKAGING CONTAMINANTS
301
by free I in textiles, have been reported in European countries. Similar reports, however, have not been forthcoming from the U.S.A. and to explain this discrepancy the authors set out to test U.S. textiles for dermatitic activity, assaying free I by the chromotropic acid method. Samples of textiles, stated to have a I content of 0.03-0.075 %, a paper towel and a facial tissue were applied to the skirt of 20 patients who previously reacted positively to 2-5 % I in routine patch tests. No signs of dermatitis were observed in these tests, nor in the same individuals wearing I-treated textiles. Hovding (Acta derm.- veneriol., Stokh. 1959, 39, 357) believed that textile-induced dermatitis was due to an excessive concentration of free I, shown by him to be present in Scandinavian finished fabrics. There is a further factor which enters into the situation, namely the widespread use of I as an anti-perspirant in Europe but not in the U.S.A. This may well be the manner in which dermatitis starts, to develop later into 'textile eczema'. Fisher, A. A., Kanof, N. B. & Biondi, Ella M. (1962). Free formaldehyde in textiles and paper. Arch. Derm. 86, 753. 288. Chromium levels in man
It is known that trivalent chromium (Cr) is involved in carbohydrate and fat metabolism and therefore appears to be an essential trace element. We have previously reported on the absence of chronic toxic effects from low levels of Cr (Cited in F.C.T. 1963, 1, 131) which may arise as a contaminant during cooking, preserving or canning. Now a comprehensive analytical survey is available of the distribution of Cr in human and animal tissues. The authors found that high concentrations of Cr were present in infant tissues~ notably in the lung, heart and kidneys. The levels diminished appreciably with age, except in the lungs. However, no accumulation of Cr was demonstrated in newborn laboratory animals. Regional differences in the Cr content of human tissues existed and it was noticeable that U.S.A. levels were well below the average, in contrast to the exceptionally high kidney Cr levels in human subjects from Bangkok and Manila. Cr levels were significantly higher in mammals other than man and this could be attributed to the greater intake of Cr in the diet of domestic and wild animals. Cr was also detected in a number of samples of potable water taken from different parts of the U.S.A. and significant differences in the Cr content, 0--7 ppb, were observed. The amount of Cr in the air varied considerably in different regions of the U S.A. and the highest Cr levels were obtained in areas of heavy industry. The average total daily intake of 30-140 tzg of Cr by man was derived from food, 30-100 /ag; water, 0--40/ag and air, 0-0.3 tzg. A very high proportion of dietary Cr was excreted in the faeces; most of what was absorbed returned to the intestine in the bile and only about 1% entered the general circulation, to be excreted in the urine. Traces might be stored, probably in an insoluble form, in the lungs. In contrast to cadmium and lead, Cr is easily eliminated from the animal body and therefore presents no toxic hazard. Schroeder, H. A., Balassa, J. J. & Tipton, Isabel H. (1962). Abnormal trace metals in m a n - Chromium. J. chron. Dis. 15, 941. 289. Molybdenum toxicology
The present study of the biological effect of molybdenum sulphate in rabbits was prompted by two facts: inorganic sulphates have been shown (Reen & Williams, Arch. Biochem. Biophys. 1956, 63, 1) to counteract poisoning by molybdenum (Mo) to some extent, and secondly rabbits have higher serum inorganic sulphate levels than man and many laboratory and farm animals. In this investigation rabbits were given 0.20-0.23 % of sodium molybdate in the diet for periods ranging between 3 and 4 weeks. In over 50 % of the test animals signs of Mo poisoning were manifest as rotation of the lower part of the foreleg