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M Layrisse

Publications and source records attributed to M Layrisse.

At least 37 records · Page 2Linked to original sources
PubMed1976

Sugar as a vehicle for iron fortification.

Sugar as a vehicle for iron fortification presents several advantages over the other vehicles used in the last three decades. In vitro studies demonstrated that ferrous sulfate added to sugar in proportion of 1 mg to 1 g, respectively, is maintained in the ferrous form for a period of at least 1 year and does not induce adverse changes in the vehicle. Sugar, by itself, carries practically no inhibitors for the absorption of iron. Iron absorption from fortified sugar mixed with vegetals is the same as that of native vegetal iron. The absorption from fortified sugar is increased more than 50% over that observed from native vegetal when it is administered as a drink during the ingestion of a meal. A further increase in absorption was found when fortified sugar was administered with beverages. The mean absorption ratio of fortified sugar given with orange juice, Coca-Cola, and Pepsi-Cola to a reference dose of iron ascorbate was between 0.45 and 0.66, which is more than 3 times the absorption of this iron fortification mixed with vegetals. The mean absorption ratio from coffee was 0.30, and from coffee with milk, 0.15. These data indicate that the fortification of sugar with iron could be a better procedure for the prevention of iron deficiency than the iron fortification of bread and wheat products, from which iron is poorly absorbed. It could be used in developing countries where beverages are highly consumed by the low socioeconomic class. This program could be extended to all sugar consumption or be restricted to soft drinks.

Absorption↗
PubMed1976

Sugar as a vehicle for iron fortification: further studies.

The data presented confirm the advantages of sugar as a vehicle for iron fortification over other vehicles used in the past. The absorption comparison between ferric and ferrous salts added to sugar demonstrated that Fe(III)-EDTA Complex and ferrous sulfate exhibited the highest absorption, while ferric ammonium citrate was poorly absorbed. It was also found that Fe(III)-EDTA reacts slowly with the tannin contained in tea; the color of the tea changes slightly in the first 2 hr after the addition of the fortified sugar. Iron absorption of sugar fortified with ferrous sulfate was tested in seven beverages. The mean absorption ratio from fortified sugar given with beverages to reference dose of iron ascorbate ranged between 0.42 and 0.70, that is, more than 4 times the absorption from fortified sugar when it is administered with a meal containing one or more vegetals. An absorption of between 0.25 and 0.80 mg of iron/soft drink sugar fortified with 3 mg of iron as ferrous sulfate can be expected in subjects with various degrees of iron deficiency. Thus, two soft drinks per day between meals would be enough to meet the iron requirement in more than 95% of menstruating women, even though the daily iron absorption from the diet is about 0.8 to 1.0 mg.

Absorption↗
PubMed1976

Iron absorption by humans from hemosiderin and ferritin, further studies.

Iron absorption from hemosiderin and ferritin biosynthetically labeled with radioactive iron has been studied in 61 subjects. The geometrical mean iron absorption from hemosiderin in both normal and iron deficient subjects was 3.4%. Its mean absorption ranged from 1.9% in normal subjects to 4.7% in subjects with moderate iron deficiency and 7.3% in subjects with marked iron deficiency. The iron absorption from hemosiderin was markedly increased when it was administered with ascorbic acid or liver. The absorption of iron from hemosiderin when hemosiderin and wheat were consumed in a meal, was lower than the absorption from wheat. Iron from liver ferritin and liver hemosiderin were less absorbed in this study than that previously reported for liver hemoglobin. The studies presented here support the possibility that ferritin and hemosiderin form an iron pool different from the non-heme pool formed by vegetal iron, egg iron and ferric and ferrous salts.

Absorption↗
PubMed1975

LD homozygous cells in the Warao population: a possible new allele at the LD1 locus within the main histocompatibility region in man.

A Venezuelan isolate indigenous population, the Warao, with a very large proportion of HL-A identical unrelated subjects non-reacting in MLC, has been considered a good potential source of LD homozygous cells. Cultures with lymphocytes from the members of several selected Warao families were performed with this aim and results obtained from three families are reported. In two of the families the parents share haplotype 2,5 and two of the siblings are SD double homozygous 2,5; in the third family, the common haplotype was 2,W15 and two of the siblings are also double homozygous 2,W15. Mixed lymphocyte cultures within the families have revealed that the SD homozygous children do not stimulate the cells from either parent thus being LD homozygous as well. Negative bilateral stimulation between 2,5 LD homozygous cells indicates that the LD1 allele carried by these individual's lymphocytes is the same; the negative MLC response of the 2,W15 LD homozygous cells to the 2,5 cells used as stimulators suggest either that their LD determinant is identical or the LD W15 allele is included in the LD5. As the Warao show a very large proportion of MLC identical individuals and a very high incidence of HL-A5 and W15, it is postulated that the LD allele(s) here described will be found in high frequency in this population.

Alleles↗
PubMed1975

Ferritin iron absorption in man.

The iron absorption from ferritin and hemosiderin biosynthetically labeled with radioiron was studied in 108 subjects. The geometric mean absorption of ferritin iron in both normal and iron-deficient subjects was 1.9 percent. Its mean absorption ranged from 0.9 percent in normal subjects to 2.5 percent in subjects with moderate iron deficiency and 5.7 percent in subjects with marked iron deficiency. The administration of this iron compound with vegetals in a meal showed distinctly lower absorption values than the absorption from either maize, wheat, or soybean. Ferritin iron absorption was also different from that of ferric chloride when they were administered together as a drink or mixed with maize or liver. The iron absorption from ferritin was markedly increased when it was administered with either meat or liver, but it did not reach the absorption level of these foods. It is still to be elucidated whether the difference in iron absorption between ferritin and vegetable foods administered together reflect that this iron is incompletely miscible with a nonheme iron pool or that it really forms a third iron pool.

Administration, Oral↗
PubMed1975

The genetic structure of a tribal population, the Yanomama Indians XI. Gene frequencies for 10 blood groups and the ABH-Le secretor traits in the Yanomama and their neighbors; the uniqueness of the tribe.

In this paper we present the results of blood group typings for a total of 33 villages distributed among five South American Indian tribes--Yanomama (21 villages), Makiritare (eight villages), Macushi (two villages), Piaroa (one village), and Wapishana (one village). These new results for the Yanomama and Makiritare tribes have been combined with those previously reported to allow a better appreciation of the distribution of allelic frequencies in the tribes. The relationship of the Yanomama to other South American Indian tribes is investigated using data on six polymorphic loci (Rh, MNS, Fy, Jk, Di, Hp). By use of four genetic measures (two of genetic relationship and two of genetic diversity), we demonstrate that the Yanomama are genetically unique among a sample of 20 South American tribes. In addition, the Yanomama show somewhat less genetic diversity for the six loci analyzed than the average South American tribe. Taken together, these results indicate a rather long period of isolation for the population antecedent to the Yanomama--perhaps since the time of entry of man into the South American continent. The pattern of genetic relationships and genetic diversity for the 20 tribes is consistent with the hypothesis that evolution in South America proceeded by a process of fission-fusion leading to isolation of subpopulations with subsequent genetic differentiation as a consequence of population isolation. The uniqueness of the Yanomama appears to stem entirely from such a process, there being no evidence of any selective differential for the loci analyzed.

ABO Blood-Group System↗