Characterization of the carcinogen 2-amino-3,8-dimethylimidazo[4,5- f]quinoxaline in cooking aerosols under domestic conditions

Lung cancer in women is the leading cause of cancer death in Taiwan. Most Chinese women are non-smokers and 60% of female lung cancer patients have adenocarcinomas. Epidemiological data indicate that the incidence of lung cancer among Chinese women may be correlated with cooking fumes. However, the carcinogenic compound(s) in cooking fume aerosols is not defined. In the present study, the cooking aerosols from Chinese stir-frying of fish were prepared under domestic conditions. To determine the mutagenic compounds in the cooking aerosol, mutagens were purified by two steps of high-performance liquid chromatography (HPLC), and their mutagenicity was monitored with Salmonella typhimurium TA98. The mutagen was eluted as a single peak. The chemical structure of the mutagenic fraction of cooking aerosol from frying of fish was characterized by UV spectra and electrospray mass spectrometry. The bacterial indirect-acting mutagenic compound in the cooking aerosol extract was determined to be 2-amino-3,8- dimethylimidazo[4,5-f]quinoxaline (MeIQx). An amount of 0.25 ng MeIQx/g of meat per min was estimated based on the mutagenic response. These data indicated that significant amounts of MeIQx (268.1 ng/Chinese dish of frying fish) were present in cooking aerosol in a short time. Chinese women spend approximately 1 h preparing meals everyday, thus, they may be exposed to significant amounts of MeIQx from cooking aerosols in the kitchen.      

Job and industry classifications associated with sarcoidosis in A Case-Control Etiologic Study of Sarcoidosis (ACCESS)

OBJECTIVES: To determine whether specific occupations and industries may be associated with sarcoidosis. METHODS: A Case Control Etiologic Study of Sarcoidosis (ACCESS) obtained occupational and environmental histories on 706 newly diagnosed sarcoidosis cases and matched controls. We used Standard Industrial Classification (SIC) and Standard Occupational Classification (SOC) to assess occupational contributions to sarcoidosis risk. RESULTS: Univariable analysis identified elevated risk of sarcoidosis for workers with industrial organic dust exposures, especially in Caucasian workers. Workers for suppliers of building materials, hardware, and gardening materials were at an increased risk of sarcoidosis as were educators. Work providing childcare was negatively associated with sarcoidosis risk. Jobs with metal dust or metal fume exposures were negatively associated with sarcoidosis risk, especially in Caucasian workers. CONCLUSIONS: In this study, we found that exposures in particular occupational settings may contribute to sarcoidosis risk.     

Evidence for a bicuculline-insensitive long-lasting inhibition in the CA3 region of the rat hippocampal slice

Long-lasting inhibition (up to 2 s) of the commissurally-evoked response in the CA3 region of hippocampal slices was observed following a mossy fibre or commissural conditioning stimulus. Bicuculline applied iontophoretically or by superfusion (1-5 X 10(-6) M) blocked the early phase (20-40 ms) of the post-stimulus inhibition but either had no effect or potentiated the later inhibition.     

Deficiency of ascorbic acid in experimental diabetes. Relationship with collagen and polyol pathway abnormalities

The plasma and tissue concentration of ascorbic acid (AA) is reduced in diabetes. This study was designed to investigate the mechanism and significance of this phenomenon. The low plasma AA concentration of diabetic rats can be normalized by dietary AA supplement (20-40 mg/day), a dosage approximately equal to the maximal synthetic rate of this substance in the rats. Treatment of diabetic rats with this regime prevented the decrease in activity of granulation tissue prolyl hydroxylase (PRLase), an AA-dependent enzyme required for maintaining the normal properties of collagen. The decreased plasma AA concentration and granulation tissue PRLase activity in diabetes can also be normalized by the aldose reductase inhibitor tolrestat. We conclude that in diabetic animals there is a true deficiency of AA that may be responsible for some of the changes of collagen observed in diabetes. Treatment with AA or an aldose reductase inhibitor may prevent some of the diabetic complications with underlying collagen abnormalities.     

Further studies on sodium movement in mammalian muscle

Summary 1. The efflux of Na has been followed from mammalian muscle under a variety of conditions of incubation. It is concluded that under normal circumstances (i. e. incubation in Ringer-type solution) the step controlling this efflux is desorption of the Na from the cell surface.2. The quantities of Na contained in the surface layer and in the interior of the cell have been estimated. The total non-extracellular Na of these muscles is 13.3 equiv./g., of which about one-half is intracellular, and one-half in an adsorbed phase.3. Incubation in K phosphate solution increases the rate of desorption, without affecting movement of Na across the cell membrane.4. Incubation in Ringer-type solution containing strophanthin slows the rate at which Na is transported across the cell boundary, without affecting the rate of desorption.With 3 Figures in the text     

The actions of a conformationally restricted analogue of aspartic acid on mammalian spinal neurones.

The effects of the 4 stereoisomers of 1-aminocyclopentane-1,2-dicarboxylic acid (CPA), a conformationally restricted analogue of aspartic acid, have been examined on spinal dorsal horn neurones of the rat in vivo. Unlike the corresponding 1,3-dicarboxylate compounds which are glutamate analogues and markedly excitatory, the CPA isomers had no evident excitatory actions of their own. Three were weak and non-specific antagonists of other amino acid-induced excitations, while the (+)-trans isomer had a slight potentiating effect.