Revealing stiffening and brittling of chronic myelogenous leukemia hematopoietic primary cells through their temporal response to shear stress.

Cancer cell transformation is often accompanied by a modification of their viscoelastic properties. When capturing the stress-to-strain response of primary chronic myelogenous leukemia (CML) cells, from two data sets of CD34+ hematopoietic cells isolated from healthy and leukemic bone marrows, we show that the mean shear relaxation modulus increases upon cancer transformation. This stiffening of the cells comes along with local rupture events, detected as reinforced sharp local maxima of this modulus, suggesting that these cancer cells respond to a local mechanical stress by a cascade of local brittle failure events.

Extravasación pleural de sustancia quimioterápica tras canulación de vena subclavia / Pleural extravasation of chemotherapeutic substance after cannulation of the subclavian vein

La canulación de una vía venosa central no está exenta de complicaciones y una de ellas es la producción de hidrotórax por instilación de sustancias. Presentamos el caso de una paciente que presentó hidrotórax de contenido quimioterápico. El mecanismo de acción de este hidrotórax fue debido a la disección de ambas hojas pleurales ocasionada por la progresión de la punta del catéter que quedó colocado entre ambas hojas. Planteamos la necesidad de controles más exhaustivos tras la canulación de catéteres venosos centrales (AU)

Iron bioavailability from diets consumed by different socioeconomic strata of the Venezuelan population.

The iron bioavailability from three typical diets consumed by socioeconomic stratum IV (SES IV--working class) of the Venezuelan population was determined by the extrinsic label method. Although the iron content of the SES IV diets was about the same (250 mumol/d) as that of upper (SES I-III) and lower (SES V) socioeconomic strata diets, iron-replete subjects absorbed 43 and 61% more iron from the SES I-III diets than from the SES IV and V diets, respectively, and absorption from the main meal of the SES I-III diets was 100% greater. However, iron deficient subjects absorbed about the same amount of iron (45 mumol/d) from the SES IV diets as from the SES I-III diets. The SES I-III diets contained more iron absorption enhancers (ascorbic acid and meat protein) and less of the inhibitor phytate, than the SES IV and V diets. Iron absorption from the meals of four diets consumed at different times during the day was also measured. There was no significant difference in the percentage iron absorption from the same meals eaten in the morning after an overnight fast, and when eaten at the customary time of day.

Fortification of precooked maize flour with coarse defatted maize germ.

The possibility of improving the dietary value of precooked maize flour through fortification with 11% coarse defatted maize germ was investigated. The results of tests in humans presented here show that the total iron absorption from the fortified preparation is similar to that from the precooked maize alone, but with the advantage of being richer in several nutrients: protein (25%), zinc (61%), potassium (47%) and magnesium (112%), as well as fiber (34%). Fortification lowers (by 20%) rather than raises the cost of the flour, and may be an important contribution to the diet of those populations where maize bread is a major component of the diet.

The relationship between iron deficiency and anemia in Venezuelan children.

The iron status of 3228 subjects from the nutrition survey Proyecto Venezuela was studied. The sample included children from 1 to 16 y of age grouped by age and sex. Values for three indicators of iron status were compared: hemoglobin concentration, serum ferritin concentration, and percentage saturation of serum transferrin. In all groups there was a strong overlap in the hemoglobin concentration distribution curves for non-iron-deficient and iron-deficient subjects classified as such according to the other two indexes. The prevalence of iron deficiency ranged from 35% in 1-3 y olds to 10% in adolescent males, the values being almost identical in the nonanemic group compared with the total population. In the different groups, 80-97% of the subjects with abnormal values of at least one of these two indexes were not anemic. The difficulties involved in establishing a state of iron deficiency according to these indexes are discussed.

Relationships among iron absorption, percent saturation of plasma transferrin and serum ferritin concentration in humans.

The percent absorption of iron from four dietary sources was compared in 2018 human subjects with three indicators of iron status, serum ferritin concentration, percent saturation of plasma transferrin and iron absorption from a reference dose of ferrous sulfate. Higher correlation coefficients (r) were obtained by comparing dietary iron absorption with the reference dose absorption rather than with serum ferritin; for example, r = +0.61 and r = -0.38, respectively, for a meat and vegetable meal. However, in practice serum ferritin is almost as efficient as the reference dose absorption in estimating dietary iron absorption, because the 95% confidence limits calculated from the regression equations were very similar. The values of r calculated for iron absorption versus transferrin saturation were comparable to those obtained with the other indicators only in the range of transferrin saturation values below 25%, whereas in more iron-replete subjects (transferrin saturation greater than 25%), this correlation virtually disappeared. This indicates that, although both serum ferritin and transferrin saturation reflect iron status in iron-depleted subjects, the control of iron absorption in iron-replete subjects is more dependent on iron stores as reflected in the serum ferritin concentration than the percent saturation of transferrin.

[Requirements of nutrients which participate in erythropoiesis]. / Requerimientos de nutrientes que participan en la eritropoyesis.

Proteins, some minerals and vitamins, play important roles in erythropoiesis and the survival of the red blood cell. This article deals specifically with the physiological requirements and recommended intakes of iron, folate and vitamin B12. A comparison of the physiologic iron requirements according to age and sex, and the amount of iron which is actually absorbed from the diets consumed by the lower socioeconomic strata of the Venezuelan population; indicates that these diets do not satisfy the requirements at all ages. Such disparity is most marked in children below three years of age, in adolescents and in women during their reproductive age. Failure to do so leads to varying degrees of iron deficiency. This low bioavailability of the Venezuelan diet is also observed in other Latin American diets consumed by the same low socioeconomic strata, which explains the high prevalence of iron-deficiency anemia in the vulnerable groups. The low intake of fruits and vegetables by the lower socioeconomic strata of the Latin American population prevents these sectors from consuming an adequate intake of folate, failing to fulfill the daily recommended intake (3.3 - 3.6 micrograms/kg body weight). This situation is aggravated in pregnant and lactating women who require an additional intake of 300 micrograms and 100 micrograms, respectively. Prevalence of folate deficiency in the first stage may be in the order of 30% in some regions. In the second stage of deficiency, characterized by megaloblastic changes in the bone marrow and an erythrocyte folate concentration of less than 50 micrograms/lt, it could be as high as 40% in pregnant women. Nutritional vitamin B12 deficiency does not constitute a health problem in Latin America. Various surveys in the lower socioeconomic strata have reported normal or higher than normal serum B12 concentrations, compared to well-nourished populations.

Daily physiological iron requirements in children.

Median daily iron absorption was determined in iron-replete males and females between 2 and 19 years of age from the upper and lower socioeconomic strata of the Venezuelan population. A comparison was made with iron absorption of well-nourished children, on the basis of hematological and anthropometric reference values from the U.S. The median absorption level, which was calculated from the increase in total body iron due to growth and the daily losses through exfoliation and menstruation, was also used to estimate the requirements of 95% of the population. When the requirements were expressed in terms of body weight, no significant difference in iron absorption was observed between the three Venezuelan and one U.S. groups, ranging from about 30 to 38 micrograms/kg/day in both sexes between 4 and 16 years of age. However, when the requirements were expressed without division by the weight factor, the requirements of the better nourished groups were somewhat higher than those of the Venezuelan lower socioeconomic population with, in addition, a threefold variation over the 5 to 16 year age range. These findings suggest that the total iron requirements of children at a certain age may be most adequately expressed in terms of the optimal body weight for that age.

[Hematologic profile and absorption of iron from diets consumed by a population of low socioeconomic level of 2 Venezuelan states]. / Perfil hematológico y absorción del hierro de dietas que consume la población de estrato socioeconómico bajo de dos estados de Venezuela.

Hematologic studies carried out in inhabitants of the State of Carabobo revealed that 19% of the subjects studied presented iron deficiency, this being more prominent in women and in children. Iron deficiency anemia was absent in men, while in the other groups its frequency, as registered, was from 5 to 13%. Tests for iron absorption from foods which form the average diet of the population in the Carabobo State, and the diet consumed by adults from the low socioeconomic strata in the States of Carabobo and Yaracuy, demonstrated that in normal subjects, bioavailability is lower than physiological requirements of men, women and children. In the iron-deficient subjects, its bioavailability can cover physiological needs. It is estimated that an important proportion of the population strata consuming such diets, suffer from iron nutritional deficiency, especially women during the reproductive age, and children.

Heme, ferritin and vegetable iron absorption in humans from meals denatured of heme iron during the cooking of beef.

The iron absorption from heme, ferritin and vegetable foods was tested in 63 humans (10 males and 53 females). The iron absorption from heme in beef exposed to prolonged heating was markedly reduced, following the degree of denaturation of the heme. The iron absorption from ferritin was about 31% of the absorption of the reference dose when administered with meat alone, falling to 11% of the reference dose when administered in a meal containing meat and vegetable foods. The absorption of ferritin iron was less than half that of vegetable iron. The data confirm a previous proposal that ferritin forms part of a subgroup of the non-heme iron pool.

The effect of cysteine-containing peptides released during meat digestion on iron absorption in humans.

In order to investigate the constituents responsible for the enhancing effect of meat on intestinal iron absorption in humans, two different types of peptic digestion extracts were prepared from 100 g of beef, in which the thiol groups of the resulting peptides were either oxidized (CYS-), or left untreated (CYS+). The absorption of radioiron mixed with 250 g of maize was more than twofold greater when consumed along with the CYS+ extract than with the CYS- (p less than 0.05). It is suggested that the enhancing effect of meat on nonheme iron absorption is due to cysteine, and that cysteine-containing peptides, rather than the free amino acid, are responsible for this effect.

Iron absorption by humans and swine from Fe(III)-EDTA. Further studies.

Studies on iron absorption from Na59Fe-EDTA in humans have shown that only a small proportion of the iron absorbed is excreted by the kidney, less than 1% of the dose administered. The pathway of Na55Fe-[2-14C]EDTA absorption and excretion when administered orally was studied in swine. A certain proportion (about 5%) of the 55Fe is split from the EDTA complex in the lumen of the gut, absorbed mainly from the pylorus and upper jejunum, transferred to plasma transferrin and then incorporated into the circulating hemoglobin. A small proportion of the iron absorbed, less than 1% of the dose administered, is excreted by the kidney, to a degree similar to that excreted by humans. The rest of the iron is eliminated in the feces, about 3% in a soluble form possibly still bound to EDTA and the greater part, about 92%, in an insoluble form. About 5% of the 14C is absorbed almost uniformly along the pyloric duodenal and jejunal mucosa, then transferred slowly to the plasma and excreted by the kidney within 48 hours. The rest of the 14C was excreted in the feces, about 80% in a soluble form and 20% in the insoluble fraction.

Effect of exposure to low temperature on normal and iron-deficient subjects.

Twenty-one Venezuelan peasants were segregated into three groups on the basis of measurements of iron status: seven normal subjects, six iron-deficient subjects with normal hemoglobin and eight iron-deficient subjects with a hemoglobin concentration of less than 9 g/dl. All subjects were placed in a water bath at an initial temperature of 36 degrees C. The water temperature was then rapidly lowered to 28 degrees C, and observations were made over the period of 1 h. Mean oral temperature of the first group fell 0.2, the second group 0.5, and the third group 0.9 degrees C. Mean plasma norepinephrine levels in both groups of iron-deficient subjects were significantly higher at 36 degrees C and during cold exposure compared with control subjects. Oxygen consumption was also significantly increased in both groups of iron-deficient subjects after cold exposure.

Effect of histidine, cysteine, glutathione or beef on iron absorption in humans.

One hundred thirteen subjects participated in iron absorption studies in which histidine, cysteine, reduced glutathione or beef were administered with test meals. Increasing doses of histidine from 416 to 2080 mg did not affect the absorption of 2 mg of corn iron. Reduced glutathione significantly increased the absorption from nonheme and heme iron present in black beans, corn and hemoglobin. Increasing doses of either cysteine or glutathione produce the same trend in the increase of absorption from corn iron as that observed from beef. The results suggest that the effect of cysteine on iron absorption is similar in the peptide form and as a single molecule.

[Cholesteatoma of Bichat's fissure. Observations apropos of a case]. / Cholestéatome de la fente de Bichat. Remarques à propos d'un cas.

Four reasons are evoked for presenting a case of cholesteatoma of Bichat's fissure: --its symptomatology, specific to the site of the lesion, and previously demonstrated by Gros and Vlahovitch; --its appearance on computed tomography, still relatively unknown because of the rare nature of these lesions; --the open discussions still being conducted as to the "parasellar" qualification adopted by J. Lepoire and B. Pertuiset for this localization; --and the debated question as to the best surgical approach.

Effect of cysteine on iron absorption in man.

Cysteine significantly increases, about 2-fold, the absorption from nonheme iron present in vegetable foods, hemosiderin, and of a ferric salt, when this amino acid is administered during the ingestion of foods. No enhancing effect was obtained when the amino acid was mixed with the food before the final cooking. A slight but significant enhancement of heme iron absorption was observed when a large dose of cysteine was administered during the ingestion of hemoglobin. This amino acid mimics the enhancing effect from proteins present in animal foods such as beef, lamb, pork, fish, chicken, and liver. It could be possible that proteins and cysteine share the same mechanism by which they induce an increase of iron absorption.

Fe(III)-EDTA complex as iron fortification. Further studies.

The data presented confirm the advantages of Fe(III)-EDTA as a salt for iron fortification. This iron compound exchanges completely with intrinsic wheat iron in the lumen of the gut. The iron absorption data from this salt tested with six different food vehicles compared with the absorption of ferrous sulfate administered with the same vehicles indicate that while the mean absorption from ferrous sulfate varies from 2 to 30% according to the food vehicle mixed with the salt, the absorption from Fe(III)-EDTA remains practically the same. Apparently, the iron absorption from Fe(III)-EDTA complex is slightly or not affected by the presence of vegetable foods or milk. All these data suggest that only a small amount of iron from this salt, about 10 mg/day, would be necessary to prevent iron deficiency anemia even in those populations relying for their subsistence on vegetable food only.

Fe(III)-EDTA complex as iron fortification.

Fe(III)-EDTA as iron fortification presents several advantages over the other iron salts previously used including ferrous sulfate. This iron compound exchange completely with vegetable food iron in the lumen of the gut but with the characteristics that the absorption from both, extrinsic and intrinsic food iron, is higher than that expected from other iron salfs. The comparison between the iron absorption from Fe(III)-EDTA and ferrous sulfate as iron fortification indicates that the absorption form EDTA is about twice as high than that observed from ferrous sulfate. The data indicates that only 10 to 15 mg of iron as Fe(III)-EDTA as iron fortification would be necessary to prevent iron deficiency anemia in population relying their subsistence of vegetable food only and free of parastic infection producing blood loss.

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.

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.