Hepatitis B Virus Genotype H and Environmental Factors Associated to the Low Prevalence of Hepatocellular Carcinoma in Mexico

Purpose: Hepatocellular carcinoma (HCC) is a leading health problem worldwide. Any agent causing chronic liver damage and cirrhosis is a risk factor for HCC. Genetic and environmental factors may be responsible for regional variations in the occurrence of HCC worldwide. The aim of this review was to describe the risk factors that may be contributing to low prevalence of HCC in the Mexican population. Methods: An electronic systematic search was conducted in four databases to retrieve studies on hepatocellular carcinoma inMexico. Results: Eighteen publications gave a total of 1042 HCC cases with a percentage that ranged from 0.25% to 1.87%. Cirrhosis was registered in 7 studies while the main etiologies were: HCV (66%), HBV (11%) and alcoholism (6.6%). Conclusions: In the last 50 years, the studies performed inMexicohave shown a very low incidence and/or mortality rate of HCC. These findings contrast from those reported in high endemic regions, such asAsia, where viral hepatitis and HCC are prevalent. One significant difference is the predominance of HBV genotype H in Mexico and HBV/B and C in Asia. InMexico, high endemic areas of HBV infection have been detected, mainly among the native population;however, infection seems to resolve very quickly, due to a prominent immunological response among the population. Other factors are that patients with liver cirrhosis die prematurely before that HCC can be detected. Furthermore, an environmental factor that may exert a protective effect against HCC, in spite of the high consumption of potentially aflatoxin-contaminated food products, is the neutralization of these substances by alkaline treatment. This study shows that genetic and environmental factors associated to HCC among the Mexican population are different from others reported worldwide.

The Effect of Maize Grain Size on the Physicochemical Properties of Isolated Starch, Crude Maize Flour and Nixtamalized Maize Flours

Usually, the maize cob is formed by grains of medium size. However, the extremes have larger or smaller size grains. The objective of this study was to investigate the influence of grain size from the same hybrid on the physicochemical properties of isolated starch, crude maize flours and nixtamalized maize flours. Two hybrids, one from CIMMyT-Mexico called IMIC-254 and one commercial sample from Monsanto (Puma) were studied. The isolated starch granules from small, medium, and large grains exhibit the same size and distribution. The grain size has influence in the determination of cooking and steeping times;small grains reach these parameters faster than medium and large ones. The hardness of the grain size for both hybrids does not showed statistical differences between them. The starch from small, medium and large grains is mainly composed of amylopectin;this result is confirmed by X-ray diffraction and Megazine analysis. The apparent viscosity of the isolated starches of small grains showed statistically significant higher peak values. According to these results, it is possible to use small, medium, and large grains to obtain products with the same physicochemical properties, by adjusting the cooking and steeping times and Ca2+ content.