Carmen Cabrera

Beneficial effects of green tea--a review.

Tea is the most consumed drink in the world after water. Green tea is a ‘non-fermented’ tea, and contains more catechins, than black tea or oolong tea. Catechins are in vitro and in vivo strong antioxidants. In addition, its content of certain minerals and vitamins increases the antioxidant potential of this type of tea. Since ancient times, green tea has been considered by the traditional Chinese medicine as a healthful beverage. Recent human studies suggest that green tea may contribute to a reduction in the risk of cardiovascular disease and some forms of cancer, as well as to the promotion of oral health and other physiological functions such as anti-hypertensive effect, body weight control, antibacterial and antivirasic activity, solar ultraviolet protection, bone mineral density increase, anti-fibrotic properties, and neuroprotective power. Increasing interest in its health benefits has led to the inclusion of green tea in the group of beverages with functional properties. However, although all the evidence from research on green tea is very promising, future studies are necessary to fully understand its contributions to human health, and advise its regular consumption in Western diets, in which green tea consumption is nowadays limited and sporadic.

Mineral content in legumes and nuts: contribution to the Spanish dietary intake

We evaluated the levels of essential elements as Cu, Cr, Fe and Zn, and toxic elements as Al, Ni, Pb and Cd in a total of 40 samples of different legumes and 56 samples of different nuts, that are widely consumed in Spain. These elements were determined in the samples mineralized with HNO(3) and V(2)O(5), using electrothermal atomic absorption spectrometry (ETAAS) as the analytical technique. Reliability of the procedure was checked by analysis of a certified reference material. No matrix effects were observed and aqueous standard solutions were used for calibration. In legumes, the levels ranged from 1.5-5.0 microg Cu/g, 0.05-0.60 microg Cr/g, 18.8-82.4 microg Fe/g, 32.6-70.2 microg Zn/g, 2.7-45.8 microg Al/g, 0.02-0.35 microg Ni/g, 0.32-0.70 microg Pb/g and not detectable-0.018 microg Cd/g. In nuts, the levels ranged from 4.0-25.6 microg Cu/g, 0.25-1.05 microg Cr/g, 7.3-75.6 microg Fe/g, 25.6-69.0 microg Zn/g, 1.2-20.1 microg Al/g, 0.10-0.64 microg Ni/g, 0.14-0.39 microg Pb/g, and not detectable-0.018 microg Cd/g. A direct statistical correlation between Cu-Cr, Zn-Al and Cr-Ni (P<0.05), and Al-Pb (P<0.001), has been found. The growing popularity of these products in recent years on the basis of its nutritional properties and beneficial effects, requires additional data and a periodical control. In addition, the present findings are of potential use to food composition tables.

Distribution of HLA class I altered phenotypes in colorectal carcinomas: high frequency of HLA haplotype loss associated with loss of heterozygosity in chromosome region 6p21

HLA class I loss or down-regulation is a widespread mechanism used by tumor cells to avoid tumor recognition by cytotoxic T lymphocytes, and thus favor tumor immune escape. Multiple mechanisms are responsible for these HLA class I alterations. In different epithelial tumors, loss of heterozygosity (LOH) at chromosome region 6p21.3, leading to HLA haplotype loss, occurs in 6–50% of all cases depending on the tumor entity. In this paper we report the frequency of LOH at 6p21 in 95 colorectal carcinomas (CRC) previously analyzed for altered HLA class I expression with immunohistological techniques. We used PCR microsatellite amplification of selected STR markers located on Chromosome 6 to identify LOH with DNA from microdissected tumor tissues and the surrounding stroma. Sequence-specific oligonucleotide analysis was performed in microdissected stroma and tumor cells for HLA typing, and to detect HLA haplotype loss. A high frequency (40%) of HLA haplotype loss was found in CRC. Eight tumors showed microsatellite instability. We sometimes observed two or more mechanisms responsible for HLA alteration within the same HLA-altered phenotype, such as LOH and HLA class I total loss. In 25 tumors (26%) no HLA class I alteration could be identified. These data are potentially relevant for CRC patients undergoing T-cell-based immunotherapy.

Chromium in basic foods of the Spanish diet: seafood, cereals, vegetables, olive oils and dairy products.

In the present study, graphite furnace atomic absorption spectrometry (GFAAS) was used to determine the content of total chromium in some basic foods of the Spanish diet. The seafood samples, vegetables and olive oils were mineralized previously with HNO3 and V2O5. A procedure of slurries with Triton X-100 was applied to dairy products. The temperature-time program was optimized for every type of sample. An assessment of the analytical characteristics of the method verifies their reliability. The content of Cr ranged between 0.004 and 0.079 microg/g in seafood (fresh wt.), from 0.007 to 0.456 microg/g in cereals and vegetables (fresh wt.), between not detectable and 0.625 microg/g in dairy products and between not detectable and 0.040 microg/g in olive oils. The high consumption of these products conditions the fact that they should be significant sources of Cr in the diet.

Cadmium Contamination of Vegetable Crops, Farmlands, and Irrigation Waters

Cadmium, a highly toxic element that can accumulate in living tissues, is a potential threat to the environment and to human health. The main sources of Cd contamination of vegetable crops via farm soils and irrigation waters are reviewed, as are the influence of residual sludges used as fertilizers and the indiscriminate use of pesticides. The principal sources of exposure and toxicological characteristics of Cd are described, together with its effects on human health. Current European technical and health regulations aimed at controlling Cd levels are noted, and the most common analytical techniques for measuring Cd content are summarized.

Aluminium content of drinking waters, fruit juices and soft drinks: contribution to dietary intake

Concentrations of aluminium in drinking waters (tap water, still mineral water and sparkling mineral water), fruit juices and soft drinks were determined using graphite furnace atomic absorption spectrometry (GFAAS) of samples processed with a HNO3-V205 acid digestion pre-treatment. In water samples, aluminium was determined directly. We verified the sensitivity, accuracy and precision of the method and ruled out matrix interferences. In analysed samples, aluminium values ranged from 4.2 to 165.3 microg/l in drinking water (n=41), from 49.3 to 1,144.6 microg/l in fruit juices (n=47), and from 44.6 to 1053.3 microg/l in soft drinks (n=88). According to the type of container (glass or can) statistically significant differences (P<0.01) have been demonstrated. Considering the mean daily individual consumption of these beverages in Spain, the daily dietary intake of Al supplied by this source is estimated as 156 microg/person/day. This study contributes new data on the Al content of a variety of foods and beverages in Spain and to estimate reliably the total dietary intake of aluminium.

Chromium levels in spices and aromatic herbs.

We determined the presence of chromium in a total of 72 samples of 17 different spices and aromatic herbs. Electrothermal atomization atomic absorption spectrometry (ETA-AAS) was used to determine Cr content in the samples mineralized with HNO3 and V2O5. The analytical characteristics of the proposed method were tested, and the accuracy and precision was also verified against an NBS-certified reference material. Chromium concentrations ranged from not detectable to 1.42 micrograms/g (dry wt.) and Cr presence was detected in 95% of samples. Spices and aromatic herbs are widely consumed in the Spanish diet and in the Mediterranean diet, in general.

Chromium levels in potable water, fruit juices and soft drinks: influence on dietary intake.

Potable water, fruit juices and soft drinks are some of the most widespread beverages in the habitual diet, and they can contribute to chromium dietary intake. We determined the concentration of chromium in 90 different samples of beverages widely consumed in Spain. Graphite furnace atomic absorption spectrometry was used to analyze samples processed with a HNO3-V2O5 acid digestion pretreatment. In water samples Cr was directly determined. We verified the sensitivity, accuracy and precision of the method and ruled out matrix interferences. In analyzed samples, chromium values ranged from not detectable to 11.80 micrograms/l in potable water, from not detectable to 17.60 micrograms/l in fruit juices and from 3.60 to 60.50 micrograms/l in soft drinks. The chromium levels we encountered are low and the contribution of non-alcoholic beverages to dietary intake of this element, have been estimated to be 0.41 microgram/day in the common Spanish diet.

Cadmium levels in wine, beer and other alcoholic beverages: possible sources of contamination

An accurate and precise method is described for the direct determination of Cd in wine, beer and other alcoholic beverages by electrothermal atomization-atomic absorption spectrometry (ETA-AAS). The graphite furnace program was optimized and samples were pretreated with nitric acid and pentoxide vanadium in a digestion block at 120 degrees C for 90 min. The results obtained were validated against microwave acid sample digestion. The analytical detection limit was 0.5 pg. The proposed method was applied to determine Cd in 134 samples of 10 different alcoholic beverages. The mean values ranged from 0.10 to 15.38 microg/l in wine, from not detectable to 0.80 microg/l in beer, and from not detectable to 11.52 microg/l in other alcoholic beverages such as cider, brandy, rum, whisky, gin, anisette, liquor and spirits. The wide variability of the results obtained emphasizes the multiplicity of factors that can influence the presence of Cd in these products. Because alcoholic beverages are widely consumed, they contribute a large fraction of cadmium intake, and therefore, strict control of this element is advisable.

Mutation analysis of genes that control the G1/S cell cycle in melanoma: TP53, CDKN1A, CDKN2A, and CDKN2B

BackgroundThe role of genes involved in the control of progression from the G1 to the S phase of the cell cycle in melanoma tumors in not fully known. The aim of our study was to analyse mutations in TP53, CDKN1A, CDKN2A, and CDKN2B genes in melanoma tumors and melanoma cell linesMethodsWe analysed 39 primary and metastatic melanomas and 9 melanoma cell lines by single-stranded conformational polymorphism (SSCP).ResultsThe single-stranded technique showed heterozygous defects in the TP53 gene in 8 of 39 (20.5%) melanoma tumors: three new single point mutations in intronic sequences (introns 1 and 2) and exon 10, and three new single nucleotide polymorphisms located in introns 1 and 2 (C to T transition at position 11701 in intron 1; C insertion at position 11818 in intron 2; and C insertion at position 11875 in intron 2). One melanoma tumor exhibited two heterozygous alterations in the CDKN2A exon 1 one of which was novel (stop codon, and missense mutation). No defects were found in the remaining genes.ConclusionThese results suggest that these genes are involved in melanoma tumorigenesis, although they may be not the major targets. Other suppressor genes that may be informative of the mechanism of tumorigenesis in skin melanomas should be studied.