Safety assessment of propyl-propane-thiosulfonate (PTSO): 90-days oral subchronic toxicity study in rats

Propyl-propane-thiosulfonate (PTSO) is one of the main organosulfur compounds present in Allium essentials oil. Different applications in the food sector have been proposed for PTSO, such as food and feed additive and as active packaging. However, the authorization of its use depends on its toxicity profile. Thus, as a part of its safety assessment, in this work a repeated dose 90-day oral toxicity study has been conducted for the first time in rats following the OECD guideline 408. PTSO was administered to groups of 10 male and 10 female rats at dose levels of 0, 14, 28, and 55 mg/kg/day. No clinical signs or mortality and no changes in body weight, food consumption and feed conversion efficiency were detected through the study. Moreover, no treatment-related changes in hematological and biochemical parameters were observed, for either sex or dose groups. The histopathology study performed revealed no differences in organ weights, and no morphological and histopathological changes were observed. Based on these results, the no-observed-adverse-effect level (NOAEL) of PTSO was judged to be ≥ 55 mg/kg/day for both sexes.

In vitro assessment of cyanotoxins bioaccessibility in raw and cooked mussels

The oral route by ingestion of water and food contaminated with cyanotoxins is the main route of exposure to these toxins. This study addresses for the first time the bioaccessibility of some of the most common Microcystins (MC-LR, MC-RR and MC-YR) and Cylindrospermopsin (CYN) simultaneously in raw and steamed mussels spiked at 250 ng/g fresh weight of each cyanotoxin, after an in vitro digestion, including the salivary (incubation with artificial saliva, 30s), gastric (with pepsin, 2h, pH 2), duodenal (with pancreatin and bile salts, 2h, pH 6.5) and colonic phases (with lactic-acid bacteria, 48h, pH 7.2). The results obtained suggest that the potential absorption of these cyanotoxins by consumption of contaminated mussels is lower than expected. After the total effect of cooking and digestion, the mean bioaccessibility levels recorded were 24.65% (CYN), 31.51% (MC-RR), 17.51% (MC-YR) and 13.20% (MC-LR). Moreover, toxins were transferred to the steaming waters at 3.77 ± 0.24 μg L^-1 CYN, 2.29 ± 0.13 μg L^-1 MC-LR, 6.60 ± 0.25 μg L^-1 MC-RR and 3.83 ± 0.22 μg L^-1 MC-YR. These bioaccessibility results should be considered for a more accurate risk assessment related to these cyanotoxins in mussels, including the fact that the steaming waters could also represent a risk after human consumption.

[Mortality trends due to myocardial ischemia in capital cities of the metropolitan areas of Brazil, 1979-89]

PURPOSE

To study the trends of mortality rates from cardiovascular diseases (CVD) and coronary heart disease (CHD) in eight capitals of Brazil.

METHODS

Death rates for these cities were studied in men (M) and female (F), standardized using the population of São Paulo, SP, 1980. Rates were calculated for CVD (ICD-9: 390-459) and CHD (ICD-9:410-414). The cities were Belém, Recife, Salvador, Belo Horizonte, Rio de Janeiro, São Paulo, Curitiba and Porto Alegre. Using simple linear regression, we obtained the annual difference in rates with a confidence interval of 95%.

RESULTS

For CVD a decline was detected of -2.6% (M) and -2.69% (F) in Belém; in Salvador, -1.53% (M) and -1.70% (F) and in São Paulo, -1.27% (M) and -1% (F) and for F in Belo Horizonte (-0.82%) and in Curitiba (-1.52%). Recife, Porto Alegre and Curitiba (M) showed stability during the period. There was a rise of the rates in Rio de Janeiro +1.37% (M) and +0.84% (F) and for M in Belo Hozironte (1%). The rates for CHD showed a decline in Belém-2.64% (M) and -2.74% (F); São Paulo, -1.4% (M) and -1.06% (F) and for F in Belo Horizonte. A stable trend was detected in Salvador, Curitiba, Porto Alegre and for M in Belo Horizonte. There was a rise in the rates of Recife +3.5% (M) and +4.4% (F) and in Rio de Janeiro +2.34% (M) and +2.53% (F).

CONCLUSION

The magnitude of death rates and of the time trends showed in this paper reveal important regional differences. Questions related to the different assignment of diagnosis in the chapter of CVD could explain some of the observed trends. However, the rise of mortality rates in Rio de Janeiro could hardly be explained by classificatory matters. Tobacco, diet and medical care could explain the rise of mortality from CVD and CHD in Rio de Janeiro.