COVENIN 474 97 PDF

Registro de Lesionados de Trabajo. Uploaded by Guillermo Garcia. registro clasificación y estadística de lesiones de trabajo Covenin C-R norma covenin – Free download as PDF File .pdf), Text File COVENIN (Registro, Clasificacion y Estadisticas de Lesiones en el Trabajo). COVENIN EXTINCION DE INCENDIO-ROCIADORES. Uploaded COVENIN (Registro, Clasificacion y Estadisticas de Lesiones en el Trabajo).

Author: Vudocage Mujar
Country: Namibia
Language: English (Spanish)
Genre: Software
Published (Last): 16 January 2004
Pages: 253
PDF File Size: 6.19 Mb
ePub File Size: 15.25 Mb
ISBN: 613-4-31300-595-4
Downloads: 22471
Price: Free* [*Free Regsitration Required]
Uploader: Vigami

After intraperitoneally or intravenously administered fumonisin B 1 has been distributed, its initial elimination is rapid, with no evidence of metabolism.

Many of these effects might be relevant to the toxicity of fumonisins. Lower incidences were recorded in the western part of the Caspian littoral. Similar pathological lesions and effects were seen in the livers and cogenin of males and females. The second mechanism involves changes in the polyunsaturated fatty acid and phospholipid pools. Thus, fumonisin-induced disruption of lipid metabolism is observed both in vitro and in vivo. Experimental evidence for synergistic interactions between aflatoxin B 1 and fumonisin B 1 Gelderblom et al.

Fumonisin production by F. Altered prostaglandin and arachidonic acid-induced cytotoxicity. No lesions Bondy coveinn al.

Untitled Prezi by Angel Peña on Prezi

The first proposed lipid-based mechanism involves inhibition of ceramide synthase, a key enzyme in the biosynthesis civenin sphingolipids reviewed extensively in WHO, a. The population-based cancer registry in Zimbabwe showed cancer incidence rates similar to those in other countries of sub-Saharan Africa, with high rates of cancers of the liver, prostate, cervix, and oesophagus Bassett et al.

Use of fumonisin B 1 FB 1 in research: Interference with folate metabolism has been covehin to the development of neural tube defects, as supplementation with folate decreased the risk Missmer et al. No lesions were reported in the kidney, but some were detected in the adrenal cortex presumably a normal physiological reaction to stress induced by the treatment in all females given the highest dose and two females given the next lowest dose Table 4; Voss et al.

Hence, analytical methods and surveys have been developed mainly for these two toxins.

norma venezolana covenin 474 pdf

A dramatic increase in the incidence of oesophageal cancer in the Transkei region of Eastern Cape Province, South Africa, was first described by Burrell; Burrell et al. These species cause Fusarium kernel rot of maize, an important disease in hot climates.

  DEATHWATCH FIRST FOUNDING PDF

Populations who consume large amounts of maize and maize products e. Imposition of limits on the concentration of fumonisins in maize in international trade would probably affect the intake of fumonisins, especially at the high end of the distribution.

Analyses of hair, serum, and urine indicated that the molybdenum content cvenin significantly lower in men from Linxian than from the low-incidence areas of Yuxian and Xinyangxian. The changes in fatty acid and phospholipid metabolism that probably alter cell regulation are changes in the degree of saturation of fatty acids in the phospholipid pools, increases in the ratio of phosphatidylcholine to phosphatidylethanolamine, changes in prostaglandin biosynthesis, and altered ceramide production.

A re-evaluation of the renal tumours Hard et al. The effect of propionate preservatives on the growth of F.

No association was found 44 alcohol intake, while smoking was a mild risk factor. Models or processes not summarized previously WHO, a are shown in bold. Formation of fumonisins in the field correlates with the occurrence of F.

norma venezolana covenin pdf

As no aflatoxin was detected in the samples, it was suggested that the food contained other toxic principles that were responsible for the lesions.

Thus, inhibition of ceramide synthase by fumonisin B 1 can cause a wide spectrum of changes in lipid metabolism and associated lipid-dependent signalling pathways reviewed by Merrill et al. The predicted intake of fumonisins in the third scenario, which describes the potential intake of fumonisins by persons who eat maize in place of all other grains, is appreciably higher than those in the first two scenarios.

Fumonisin B 1 potentiated the effect of iron on lipid peroxidation and was toxic to the liver, independently of its effect on lipid peroxidation Lemmer et al. A survey in Henan, Hebei, and Shanxi, three provinces in northern China, showed that the highest mortality rates from oesophageal cancer were those in two counties, Yancheng and Hebei, with crude rates of and perrespectively Yang, A later study with a synthetic, optically active gamma -lactone related to the tricarboxylic acid correlated this with the same lactone in fumonisin B 1 and confirmed the R configuration for the chiral site on the side-chains Edwards et al.

The ceramide generated from these complex sphingolipids is dihydroceramide, the form of ceramide that is inactive in ceramide signalling and does not induce apoptosis of oxidant-damaged hepatocytes Arora et al.

  ALCAMO FUNDAMENTALS OF MICROBIOLOGY 8TH EDITION PDF

It has been proposed that glycerophospholipids and the sphingolipid cycle interact to control a variety of cellular processes, including apoptosis. Using mild electrospray ionization mass spectrometry, Pocsfalvi et al. A similar interactive pathway is likely to exist for fumonisins in the liver to regulate processes related to cell proliferation and apoptosis.

At each temperature tested in a specific food-processing system, the stability of the fumonisin was time-dependent Jackson et al. For example, increased expression of hepatocyte growth factor, transforming growth factor TGF – alpha and especially TGF- beta 1 and c- myc was seen in rat liver during short-term feeding with fumonisin B 1 Lemmer et al.

Mouse macrophage Inhibition of arachadonic acid release [0.

The consumption of pickled vegetables heavily infested with various Aspergillus and Fusarium spp. The standardized mortality rate for oesophageal cancer among men in Pordenone Province in 4744 Friuli—Venezia Giullia region of northeastern Italy was 17 per Franceschi et al.

Toxic hepatosis occurs concurrently. A diversity of alterations in cellular regulation resulting from disruption of sphingolipid metabolism by fumonisin B can also be expected. Of all the agriculturally important species studied, fetal male rabbit appeared to be the most sensitive to fumonisin-induced toxicity, on the basis of decreased absolute kidney weight LOEL, 0.

The male kidney was the most sensitive target for fumonisin B 1and the liver was more severely affected in females than in males. Toxicity was monitored by bimonthly clinical chemical analyses throughout treatment, and liver biopsy samples were taken at regular intervals up to 4. For commodities that contribute significantly to intake, distribution curves should be generated to provide options to governments and national and international regulatory agencies for use in risk management.

The distributions representing variation and uncertainty were selected iteratively to form a two-dimensional array of estimates of the magnitude of harm to individuals and to the population as a civenin.

The intake of fumonisins at the Although nine countries submitted information on the concentrations of fumonisins in maize and maize-based foods, only the United Kingdom presented information that allowed estimation of national intake of fumonisins.