We have presented in some detail the more common clinical syndromes produced by the ingestion of natural seafood toxins, and touched on those that could be of interest to the international traveler and to the sport fisherman. For the practicing allergist, knowledge of this wide array of clinical syndromes of toxicity is of paramount importance for the proper differential diagnosis of seafood allergy. In the majority of cases, the diagnosis is clinical, and therefore a careful history and physical exam are essential.
This thesis seeks to analyse price inflation under oligopoly capitalism. Its central argument is that under oligopoly capitalism, price inflation is a structural phenomenon. For a greater understanding of that phenomenon, the adoption of the inter-industrial approach for its analysis seems essential. According to this approach, price inflation can be initiated in a single industry or in an industry group. The initiating factor may be an increase in the mark-up, an increase in the money wage rate or an increase in the foreign currency price of an imported input. It can also be initiated by devaluation. The input-output matrix, the core of the economic system, is the key to the transmission of inflationary impulses (in the form of higher unit cost) from one industry to another. Real wage resistance, rigid mark-up resistance, and rigid foreign resistance do no more than perpetuate or worsen the inflationary experience. The inflationary process itself has a dual role to play. It acts as a mechanism for shifting income distribution in favour of one section of the society against another and as a mechanism for changing the price structure. The author argues that the abandonment of the macroeconomic approach to the analysis of price inflation and its replacement by the inter-industrial approach is the first step for serious analysis of that structural phenomenon.
Five groups of female mice were fed from day 14 of pregnancy and throughout lactation on synthetic diets differing only in the lipid component, which constituted 10% of the diet and was derived from (a) the lipid fraction extracted from yeast grown on n-alkanes, (b) commercial soya lecithin, (c) fatty acids isolated from yeast lipids (odd-chain fatty acids), (d) lipids extracted from yeast grown on glucose or (e) margarine (8%), corn oil (1%) and the unsaponifiable fraction (1%) from yeast grown on n-alkanes. A control diet (9% margarine and 1% corn oil) was fed to a sixth group of pregnant mice and to the offspring of all the groups from weaning to 60 days after birth. A battery of behavioural tests was performed on the offspring of the six groups between days 1 and 16 after birth (reflex activities), between days 2 and 21 (locomotor activity) and at 60 days of age (avoidance learning). An acceleration of postnatal behavioural maturation was evident in the pups of animals fed lipids from yeast grown on n-alkanes and of those fed soya lecithin, indicating the involvement of phospholipids and odd-chain fatty acids in the aspects of development studied.
Nitrites are present in a wide variety of foods and their daily intake in man has been estimated at 1.5 mg. Ethylenethiourea (ETU), a major food contaminant resulting from degradation of ethylenebisdithiocarbamate fungicides, is a potent rat teratogen. The co-administration of ETU (60 or 40 mg/kg) and NaNO2 (80 mg/kg) to rats by gavage on day 15 of gestation resulted in a higher survival of progeny than occurred with the corresponding dose of ETU alone. In a second study, ETU (60 mg/kg) and NaNO2 (80, 100 or 120 mg/kg) were administered, either individually or in combination, as a single dose on day 13 of gestation. Administered alone, NaNO2 did not produce any teratogenic response in full-term foetuses, whereas ETU produced a high incidence of various anomalies. However, the combined dosing resulted in the elimination of almost all the anomalies. The reducing effect of NaNO2 on ETU-induced malformations was reversed when the animals were pretreated with 200 mg ascorbic acid/kg or 360 mg sodium ascorbate/kg. Since both of these are well-known inhibitors of N-nitrosation reactions, it was presumed that the simultaneous oral dosing of ETU and NaNO2 resulted in the formation of N-nitrosoethylenethiourea.
Patulin, a secondary metabolite produced by species of the genera Penicillium and Aspergillus, was administered to male Sprague-Dawley rats, weighing 50–60 g, by the oral, sc and ip routes. The 72-hr LD50 values (in mg/kg weight) were: oral, 55·0; sc, 11·0; ip, 10·0. Mortality was greatest 0–24 hr after administration by the oral and sc routes and 49–72 hr after ip dosing. Gross alterations consisted of gastric and intestinal hyperaemia and distention. Histopathological alterations consisted principally of ulceration and inflammation of the stomach. Patulin was administered orally to rats daily or every other day for 2 wk at doses of 50 or 75% of the oral LD50. Mortality in the treated groups was greater than in controls but was similar for all treated groups. No evidence of cumulative toxicity was found and the gross and histopathological alterations were similar to those found in the LD50 studies. Clinicopathological alterations included metabolic alkalosis with respiratory compensation, oliguria, decreased serum sodium, elevated blood glucose, reduced plasma protein and an elevated total leucocyte count which differential leucocyte counts indicated to be due to neutrophilia. The inflammatory alterations observed in the gastro-intestinal tract may be due to the irritant properties of patulin or to an alteration in the gastro-intestinal flora by the antibiotic activity of patulin.
Groups of rats were given metatartaric acid in the drinking-water in concentrations of 0 (control), 0·1, 0·5 or 3·0% for 18 wk. No effects associated with treatment were seen in the results of the haematological examinations and serum analyses. The treated animals consumed less water and food than the controls, probably because of the unpalatability of the test material. Administration of the 3% solution was associated in males with a reduced growth rate, some impairment of urine-concentrating ability during prolonged water deprivation (also seen in males on 0·5%) and histopathological changes in the stomach indicative of an inflammatory response in the submucosal layer. Both sexes of the 3% group showed an increase in relative kidney weight, without accompanying histopathological change. The no-untoward-effect level in this study was 0·1% metatartaric acid in the drinking-water, equivalent to a mean daily intake of 80 mg/kg body weight in the males and 130 mg/kg in the females.
5-Methoxypsoralen (5-MOP) is used in cosmetic suntan preparations to stimulate the production of skin pigments. Although its isomer 8-methoxypsoralen (8-MOP) has been shown to be genotoxic in numerous biological systems, 5-MOP has not been so extensively investigated, but it has recently been reported to be mutagenic and carcinogenic. We have studied the lethal effects of 5-MOP and near ultraviolet light (NUV) on repair-deficient Escherichia coli strains. After treatment with 5-MOP at concentrations above 2 μg/ml in combination with UV light survival of the repair-deficient strains was considerably reduced and strain WP100 uvrA− recA− was more sensitive than strain WP2 uvrA−. The effect was dependent on the time of irradiation and on the presence or absence of S-9 mix which inhibited the lethal activity of 5-MOP/NUV particularly when the NADP-generating system was included. These results support other indications that the use of 5-MOP in cosmetic preparations should be controlled.
The effects of folic acid administration on the weight, protein, water content and microsomal 5′-phosphodiesterase of the rat kidney were determined, to elucidate the mechanisms contributing to the renal enlargement produced by this agent. Folic acid administered ip in single doses of 100–250 mg/kg caused dose-related increases in kidney weight, water and protein content within 24 hr. Time-course studies indicated that 250 mg folic acid/kg given ip produced a progressive elevation in renal water content from 2 to 72 hr. Smaller increases in whole-kidney protein were recorded 8, 24 and 72 hr after folic acid treatment. However, a biphasic response of microsomal 5′-phosphodiesterase was produced, inhibition at 16 hr being followed by stimulation (to 140% of control) at 72 hr. In vitro studies indicated that folic acid inhibits 5′-phosphodiesterase competitively, and the early inhibition of 5′-phosphodiesterase in vivo appears to be due to a direct effect of folic acid on the enzyme.
Samples of domestic (Chinese) beer were analysed for N-nitrosamines using gas chromatography-high resolution mass spectrometry with a peak-matching technique. Of 26 samples tested, 20 (77%) were found to be contaminated with N-nitrosodimethylamine (NDMA). The mean content of these samples was 2·7 μg/litre, without correction for recovery of NDMA from beer (74% with a coefficient of variance of 18%). The remaining six samples contained <0·5 μg/litre, the lower limit of detection.
The basic methylene chloride extract from 20 of 30 samples of foods fried in deep fat failed to elicit any mutagenic response that could be detected in the Salmonella typhimurium/mammalian micro-some assay. The basic extracts of the remaining ten samples (all three chicken samples studied, two of the four potato-chip samples, one of four corn-chip samples, the sample of onion rings, two of six doughnuts, and one of three samples of french-fried potato) showed evidence of weak mutagenic activity. In these samples, amounts of the basic extract equivalent to 28·5–57 g of of the original food sample were required to produce revertants at levels of 2·6–4·8 times the background level. Only two of the acidic methylene chloride extracts from the 30 samples exhibited mutagenic activity greater than 2·5 times the background reversion level, and in both cases (one corn-chip and one shrimp sample) the mutagenic response was quite weak. The basic extract of hamburgers fried in deep fat in a home-style fryer possessed higher levels of mutagenic activity (13 times the background reversion level). However, the mutagenic activity of deep-fried hamburgers is some four times lower than that of pan-fried hamburgers.
Groups of three male mice were given single oral doses of di-(2-ethylhexyl) [14C]phthalate (5 μCi; 6.72 mg/animal) and examined by whole-body autoradiography at intervals from 1 hr to 7 days after treatment. The radioactivity was excreted in the urine and faeces mainly in the first 24 hr and completely within 3–5 days. Although, following absorption, radioactivity was widely distributed, none was found in the central nervous system, skeleton or thymus, and activity was detected only rarely in the testes. There was no evidence of tissue storage.
Nitrite found in human saliva is the product of the microbial reduction of nitrate circulating through the salivary glands. Saliva samples were collected under controlled conditions from volunteers who were habitual users of different types of tobacco products (tobacco chewers, cigarette smokers, bidi smokers and masheri users) and from controls. The saliva samples were analysed for nitrite levels and for nitrate reductase activity spectrophotometrically. Samples were collected from two different areas, Bombay (urban) and Ghodegaon (rural). Salivary nitrite levels in the control groups ranged from 1·6 ppm in Ghodegaon to 11 ppm in Bombay. The nitrite levels of the masheri-using groups from both locations and of the tobacco-chewing group from Bombay were significantly higher than those of the controls. A number of volunteers showed undetectable levels of salivary nitrate reductase. Volunteers who chewed tobacco or used masheri had higher levels of nitrate reductase activity than the controls. However, there did not seem to be any clear correlation between nitrite levels and nitrate reductase activity in the saliva.
In male and female rats, R-goitrin treatment increased the relative liver weights; in some of the enlarged livers a high incidence of mitotic figures was observed. R-goitrin treatment increased the relative thyroid weight, more in male rats than in females. The thyroids of R-goitrin treated rats were either hyperplastic or had most follicles filled with pale-staining colloid and rarely follicles with normal, well-stained colloid. At certain doses, R-goitrin increased serum triglycerides, cholesterol, total protein, albumin and calcium, but it decreased serum thyroxine and urea. However, most of these changes in serum chemistry were small. R-goitrin caused a temporary increase in urinary ascorbic acid output in both sexes, but the liver ascorbic acid level was increased only in female rats. The duration of pentobarbital-induced sleep was significantly prolonged by R-goitrin pretreatment only in male rats.
The soya phyto-oestrogens (isoflavones)—genistein, daidzein (and their glucosides, genistin and daidzin) and coumestrol—are reported to contribute to the hypocholesterolaemic response to soya-protein foods. Examination of several soya-based diets for laboratory animals has shown the diets to have a highly variable content of isoflavones.
Studies were conducted to determine the effect of the pH of a vaginal douche on its irritation potential for the vaginal mucosa of the albino rabbit and albino rat. The pH of a liquid douche formulation was varied by modification of the lactic acid/sodium bicarbonate ratio and the resulting preparations were administered intravaginally by lavage once a day for four consecutive days. On day 5, the animals were killed and the vaginal tissues were processed and examined histopathologically. Using a predetermined semiquantitative scoring system, it was found that the irritation potential of the formulation under study was pH dependent in the rabbit but not in the rat. As the pH was decreased, the degree of irritation became more severe in the rabbit; at pH 3· and below, irritation was sufficiently severe for the formulation to be considered unacceptable for human use. Only minimal irritation was seen in the rat at any of the pH levels tested. The sensitivity of the rabbit vaginal mucosa is greater than that of the rat and the response is pH dependent below pH 3.0. This exaggerated response must be taken into consideration when the rabbit is used for assessing the vaginal-irritation potential of douches. The rabbit, having a vaginal mucosa more sensitive than that of the rat, remains an appropriate model for measuring the potential irritancy of new douche products, because comparisons can be made with products of known irritancy.
