PubMed Health⌕ Search

Biomedical subjects

M L Lorenzo

Publications and source records attributed to M L Lorenzo.

At least 19 recordsLinked to original sources
PubMed2001

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.

Animals↗
PubMed2001

Daily dietary intake of chromium in southern Spain measured with duplicate diet sampling.

We measured daily dietary Cr intake in southern Spain by sampling duplicate diets for seven consecutive days in different population groups. Cr was determined by electrothermal atomization-atomic absorption spectrometry. The samples were mineralized in a digestion block with HNO(3), HClO(4) and V(2)O(5). A total of 161 duplicate diets from twenty-three subjects were analysed, and mean levels of Cr intake ranged from 9.39 to 205.16 microg/d. Mean Cr intake (100 microg/d) was similar to levels found for most other countries, and was within the range recommended by the National Research Council for a safe and adequate daily intake (50-200 microg/d). Chromium intake correlated significantly with energy, protein and carbohydrate intake, and with the daily intake of Zn, Fe, Mg, K, Na, Ca and nicotinic acid in the diets analysed.

Adult↗
PubMed2001

Estimation of chromium bioavailability from the diet by an in vitro method.

An in vitro method was used to study the dialysable fraction of chromium (Cr) from the diet which simulates human gastric and intestinal digestion. The percentage of dialysed Cr was used to assess the bioavailability. The duplicate diet approach was used to obtain ten different sets of samples each representative of the normal diet consumed in southern Spain. In each case triplicate analysis of Cr was carried out by electrothermal atomization-atomic absorption spectrometry in acid-mineralized samples. The Cr dietary intake ranged from 16 to 117 microg/day, and the dialysable Cr fraction ranged from 0.4% to 1.6%. The Cr absorption was higher for low levels of daily dietary intake of Cr (< 40 microg) than for levels of 40-80 microg; for high levels (> 80 microg) there was an increase in the dialysable fraction. The energy and nutrient intake of these diets was also evaluated.

Biological Availability↗
PubMed2000

Aluminium levels in spices and aromatic herbs.

We evaluated the levels of aluminium in a total of 72 samples of 17 different spices and aromatic herbs that are widely consumed in Spain, and in the Mediterranean diet, in general. Aluminium was determined in the samples mineralized with HNO3 and V2O5, using electrothermal atomization atomic absorption spectroscopy as the analytical technique. The accuracy and precision of the proposed method was verified against an NBS-certified reference material. Precision, expressed as relative standard deviation, ranged from 1.10 to 4.07%. The results obtained from recovery studies were of 97.90 +/- 1.20. Aluminium concentrations ranged from 3.74 to 56.50 microg/g (dry wt.). The presence of this metal was detected in all the samples we analysed.

Aluminum↗
PubMed2000

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↗
PubMed2000

Now you see it, now you don't: explicit versus implicit measures of the personal/group discrimination discrepancy.

When making explicit self-report ratings, members of status- and racial-minority groups report less personal experience with discrimination than that encountered by their group--a phenomenon called the personal/group discrimination discrepancy (PGDD). This study provides evidence, for the first time, that the PGDD may be, in part, a product of the procedure used to measure it. White women and men completed explicit and implicit measures of personal and group discrimination based on sex. The PGDD surfaced among women in the explicit measures, but not in the implicit measures. These findings suggest that explicit and implicit measures might provide different assessments of experience with discrimination.

Adult↗
PubMed1999

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.

Beverages↗
PubMed1999

Trace element determination in different milk slurries.

We have studied the contents of trace elements of nutritional or toxicological interest in 90 samples of whole, low-fat, skim, condensed, evaporated and powdered milks. Slurries of the samples were prepared with Triton X-100 and analysed using electrothermal atomic absorption spectrometry. The temperature-time programme of the graphite oven was optimized for each element, and the accuracy, precision, selectivity and sensitivity of the method were verified. Concentrations of the trace elements we investigated were: Pb 0-0.211 microgram/g, Cd 0-28.985 ng/g, Al 0.528-4.025 micrograms/g, Cu 0.041-0.370 microgram/g, Cr 0-0.177 microgram/g, Mn 0.024-0.145 microgram/g, Se 0-23.333 ng/g, Zn 0.297-0.827 microgram/g and Ni 0.058-1.750 micrograms/g. (A value of zero indicates that the element was undetectable by our methods.) Concentrations of the pairs of elements Cu-Cd, Mn-Cd, Mn-Cu, Zn-Mn, Ni-Cu, Ni-Mn and Ni-Zn were significantly correlated (P < 0.001). Linear discriminant analysis confirmed the separation between the six types of milk analyzed.

Aluminum↗
PubMed1998

Aluminium levels in wine, beer and other alcoholic beverages consumed in Spain.

A reliable and rapid method is presented for the determination of Al by graphite furnace atomic absorption spectrometry (GFAAS) in wine, beer and other alcoholic beverages. The temperature-time program for the graphite furnace was optimized. Samples were digested with nitric acid and vanadium pentoxide. The results obtained were validated against microwave acid sample digestion. The analytical detection limit was 4.0 pg. The mean recovery of 98.2% and the relative standard deviation of 5.2% were obtained. The method was applied to determine Al in 70 different samples of alcoholic beverages widely consumed in Spain. The mean values ranged from 94.8 to 1682.6 micrograms/l in wine, from 36.5 to 795.2 micrograms/l in beer, and from 15.7 to 739.6 micrograms/l in other alcoholic beverages (cider, brandy, rum, whisky, gin, anisette and liquor). The influence of packaging and containers on Al contamination of alcoholic beverages and their contribution to Al dietary intake were estimated.

Alcoholic Beverages↗
PubMed1998

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.

Biological Availability↗
PubMed1998

Growth arrest of Schizosaccharomyces pombe following overexpression of mouse type 1 protein phosphatases.

Three mouse genes encoding type 1 protein phosphatase isotypes alpha, gamma and delta were expressed in Schizosaccharomyces pombe cells under the control of the regulatable promoter nmt1. In the repressed state, basal expression of mouse genes was able to rescue the S. pombe mutant dis2-11. An integrated mouse gene could not, however, genetically complement S. pombe double mutants carrying disrupted dis2 and sds21 protein phosphatase genes. Overexpression of any of the three mouse protein phosphatase1 isotypes produced growth arrest and loss of viability in wild-type S. pombe cells. Overexpressing cells showed defects in chromosome distribution and in the formation of septa. These defects are characteristic of the expression of the mammalian protein phosphatases in S. pombe, since they are not observed after overexpression of endogenous S. pombe type 1 protein phosphatases. Overexpression of a truncated version of isotype delta, which lacked protein phosphatase activity, reproduced most of the characteristics of the lethal phenotype. We conclude that the lethal effect may be due to interactions with essential cell cycle proteins.

Animals↗
PubMed1996

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.

Alcoholic Beverages↗
PubMed1996

Chromium, copper, iron, manganese, selenium and zinc levels in dairy products: in vitro study of absorbable fractions.

Because milk and dairy products are some of the most widespread foods in the human diet, they contribute a large fraction of mineral intake. We determined levels of chromium, copper, iron, manganese, selenium and zinc in 60 samples of 10 widely consumed dairy products. Graphite furnace atomic absorption spectrometry was used to analyze samples processed with a slurry procedure to minimize sample pretreatment. The accuracy and precision of our method were verified. In analyzed samples, mean values ranged from not detectable to 0.950 microgram/g for Cr, from 0.020 to 2.800 micrograms/g for Cu, from 0.750 to 20.0 micrograms/g for Fe, from 0.010 to 0.900 microgram/g for Mn, from not detectable to 0.140 microgram/g for Se, and from 0.250 to 4.500 micrograms/g for Zn. The highest levels of Cr, Cu, Fe, Mn and Zn were detected in children's milk. Increased concentrations of Cr, Cu, Fe and Mn were detected in products packaged in glazed ceramic containers. We also studied the absorbable fractions of these elements using in vitro techniques which simulate human gastric and intestinal digestion.

Absorption↗
PubMed1990

The haplotype distribution of the delta F508 mutation in cystic fibrosis families in Scotland.

The gene defective in cystic fibrosis (CF) has recently been isolated and the major mutation identified. The haplotype distribution of this mutation (delta F508) has been determined for 215 CF chromosomes in the Scottish population. delta F508 represents 73% of all CF mutations in this group. There remains considerable linkage disequilibrium between XV2c and KM19 and other mutations in the CF gene.

Chromosome Deletion↗