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Biomedical subjects

K Ghebremeskel

Publications and source records attributed to K Ghebremeskel.

At least 37 records · Page 2Linked to original sources
PubMed1999

Maternal diet high in fat reduces docosahexaenoic acid in liver lipids of newborn and sucking rat pups.

The effect of a maternal diet high in fat, similar to Western foods, and of diabetes on liver essential fatty acid composition of the mother and the newborn and sucking pups was investigated. Female Sprague-Dawley rats were fed on either a low-fat (42 g/kg) or a high-fat (329 g/kg) diet for 10 d before mating, throughout pregnancy and post-partum. On the first day of pregnancy, diabetes was induced by intravenous administration of streptozotocin in half the animals from the two diet groups. Half the pups were killed at birth, and the remaining pups and mothers at days 15 and 16 respectively. At birth, there was a significant reduction in the proportions of docosahexaenoic acid (DHA) in the liver phosphoglycerols and neutral lipids of the pups of both high-fat control and diabetic mothers compared with those of low-fat control and diabetic mothers. Diabetes decreased arachidonic (AA) and linoleic acid values in both the low- and high-fat groups at birth. The sucking pups of both the high-fat control and diabetic mothers exhibited a significant reduction in DHA and a concomitant compensatory increase in AA and a lowering in DHA-AA balance. In the mothers, the high-fat diet significantly increased the proportions of DHA in ethanolamine phosphoglycerols but had no observable effect in choline phosphoglycerols and neutral lipids. In the fetus the DHA level (g/100 g total fatty acids) was disproportionately reduced by the maternal high-fat diet. The adverse effect of the high-fat diet on the level of DHA (g/100 g total fatty acids) was greater in the neonate (and by implication the fetus) than in the sucking pups or mothers. It is concluded that a distortion of the biochemistry is induced in the offspring through a maternal high-fat diet, without genetic predisposition.

Animals↗
PubMed1998

The inadequacy of the essential fatty acid content of present preterm feeds.

UNLABELLED: Arachidonic (AA) and docosahexaenoic (DHA) acids are major components of endothelial, pulmonary and neuro-visual cell membranes. Preterm babies may be born with deficits of both AA and DHA. There is evidence that their endogenous anti-oxidant enzymes defence systems have only reached half the activity expected at term. Yet they are exposed to an oxygen tension greater than physiologically anticipated at this time, and the superoxide dismutase shows no evidence of significant catch-up. After birth, present enteral and parenteral feeds for the preterm baby result in a further drop of AA and DHA plasma proportions to a quarter or third of the intra-uterine expectation. At the same time, the proportion of linoleic acid (LA), the precursor for AA, rises in the plasma phosphoglycerides four-fold, thus denying the preterm infant the provision with which the placenta would have perfused the fetus to meet the very rapid demand for endothelial and neural growth. From the biochemistry it is predictable that this situation could lead to fragile cell membranes, leakage, rupture with peroxidation resulting in the formation of inflammatory and vasoconstrictive agents. CONCLUSION: The essential fatty acid content of current enteral and parenteral feeds for preterm infants is incorrectly formulated.

Arachidonic Acids↗
PubMed1997

Are deficits of arachidonic and docosahexaenoic acids responsible for the neural and vascular complications of preterm babies?

We review evidence suggesting that pre- or postnatal deficits of arachidonic acid (AA) and docosahexaenoic acid (DHA) together with underdeveloped antioxidant protection contribute to neurovisual developmental disorders and other complications of premature birth. These two synergistic deficits occur at a time when 70% of energy is focused on brain development and when the brain and blood vessels are growing at high speed. The types of essential fatty acids fed to preterm babies bear no relation to what the infant would have received had it remained a fetus. This failure to meet essential fatty acid requirements exacerbates the AA and DHA deficits seen at birth; furthermore, the immature superoxide defenses remain depressed until the expected date of delivery. Deficits of these systems, which are required for cell membranes, the endothelium, and neural tissue, could provide the biochemical prerequisite for the membrane disorders to which these babies are at high risk: intraventricular hemorrhage, periventricular leucomalacia, retinopathy of prematurity, and bronchopulmonary dysplasia. Although poor vascular development during fetal and neonatal life may be repaired, the structural and antioxidant deficits identified in preterm babies may impair blood vessel development with long-term consequences. The conclusion drawn from this review is that present parenteral and enteral lipid nutrition for preterm babies is flawed and could be pathogenic. Full-term milk composition is the basis for the design of preterm infant foods, but full-term milk is different from the placental product that is rich in AA and DHA. Preterm lipid nutrition should be revised to be more in line with placental lipid transfer to the fetus.

Arachidonic Acid↗
PubMed1995

Fatty acid composition of plasma and red cell phospholipids of preterm babies fed on breast milk and formulae.

UNLABELLED: Fatty acids of plasma and red cells of preterm babies, gestational age 28-33 weeks, weighing less than 2200 g were studied between birth and the expected date of delivery (EDD). Babies were fed either mothers' breast milk, or if they were unable, or chose not to breast-feed, randomly assigned to milk formula A or B. Milk B had 26% oleic acid, 0.5% docosahexaenoic acid (DHA) and 0.12% arachidonic (AA); A had 13% oleic acid, less than 0.05% AA and no DHA. The proportions of gamma linoleic and the other fatty acids, and the ratio of linoleic acid (LA)/alpha linolenic acid (ALA) were comparable in the two formulae. Diet and/or physiological adaptation seemed to be responsible for the significant changes in the proportions of certain fatty acids between birth and EDD. Incorporation of DHA in formula B increased its concentration in plasma and red cells, and reduced the conversion of LA to AA. With respect to maintenance of DHA status, milk B was superior to milk A but did not match breast milk. CONCLUSION: Fortification of formula with DHA without concomitant incorporation of AA may precipitate AA insufficiency and may have developmental implications.

Arachidonic Acids↗
PubMed1994

Vitamin A and related essential nutrients in cord blood: relationships with anthropometric measurements at birth.

Following the advice given by the Department of Health to women who are, or may become pregnant, not to eat liver and liver products because of the risk of vitamin A toxicity, the concentrations of vitamins A and E, and copper, magnesium and zinc in cord blood were investigated. The study was conducted in Hackney, an inner city area of London. Esters of vitamin A were not detected in any of the samples, indicating that there was no biochemical evidence of a risk of toxicity. Indeed, vitamin A correlated significantly with birthweight, head circumference, length, and gestation period. There was also a significant positive relationship between zinc and birthweight. In contrast, copper showed a negative correlation with birthweight and head circumference. Vitamin E and magnesium were not associated with any of the anthropometric measurements, although magnesium showed an increasing trend with birthweight. The data suggest that most of the mothers of the subjects studied may have been marginal with respect to vitamins A and E and zinc. In those with low birthweight babies. a higher intake would have improved their nutritional status and possibly the outcome of their pregnancy. For these low-income mothers, liver and liver products are the cheapest and the best source of vitamins A and E, haem iron, B vitamins and several other essential nutrients; hence the advice of the Department of Health may have been misplaced.

Adult↗
PubMed1994

Nutrition and health in relation to food production and processing.

Intensive animal rearing, manipulation of crop production and food processing have altered the qualitative and quantitative balance of nutrients of foods consumed by Western society. This change, to which the physiology and biochemistry of man may not be presently adapted to, is thought to be responsible for the chronic diseases that are rampant in the Industrialised Western Countries. Agriculture production and food processing practices, dietary habits and lifestyle of the West is being fostered without any appraisal of the health implications by most developing countries. Consequently, a rising trend in the incidences of obesity, diabetes, high blood pressure, cardiovascular diseases, dental decay and appendicitis is apparent. Mediterranean countries are adopting the agriculture and food practices of northern Europe as the result of the harmonisation of European food and agriculture policy. It is predicted that the low incidence of morbidity and mortality from coronary heart disease, stroke, diabetes and breast and colon cancer of the Mediterranean countries would rise to the high northern European level in the foreseeable future. Most of these chronic diseases are lifestyle related and are preventable. This can be realised by tackling the root problem which is food production and processing practices and not by dispensing designer drugs or opening more hospital beds.

Agriculture↗
PubMed1993

Nutrition and neurodevelopmental disorders.

Since the 1960s the structural requirements for the growth, development and function of the brain have become better understood due to the recognition of the prodigious energy needs for brain development and its structural requirements for lipids. The most vulnerable period of neural development is during embryonic and fetal growth. There is now both retrospective and prospective evidence that maternal nutrition prior to conception is most important to pregnancy outcome. Our studies on maternal nutrition in pregnancy again illustrate the relationship of maternal nutrition to birthweight and head circumference. In a study of 513 pregnancies we found that nutrient intakes in mothers of low birthweight babies were well below those of mothers whose babies were in the 3.5-4.5 Kg range at which morbidity is at its lowest. Nutrient intakes tracked with birthweight, independent of smoking and alcohol up to, but not above 3,270 g. The closest correlations were obtained with the diet of the mother at or about the time of conception rather than later in the pregnancy. Our studies also reveal that premature and intrauterine growth retarded babies were born with deficits of the types of essential fatty acids (arachidonic AA, docosahexaenoic DHA acids) known to be required for brain development. Deficits of brain DHA have been found experimentally to impair visual and cognitive development and also to cause haemorrhage, not unlike peri-ventricular haemorrhage in low birthweight babies, the above evidence is suggestive of a route to test the prevention and treatment of these types of membrane related disorders.

Cephalometry↗
PubMed1991

The effect of dietary change on in vitro erythrocyte haemolysis, skin lesions and alopecia in common marmosets (Callithrix jacchus).

1. The effect of dietary change on common marmosets (Callithrix jacchus) exhibiting high in vitro erythrocyte haemolysis, skin lesions and alopecia was investigated. 2. The experimental diet was low in lipid, high in vitamin E and was devoid of n-3 long chain polyunsaturated fatty acids. 3. There were significant increases in the concentrations of plasma alpha-tocopherol (vitamin E) (P less than 0.05), all-trans retinol (vitamin A) (P less than 0.001) and total lipid (P less than 0.025), and a reduction in fibrinogen (P less than 0.02) concentration and neutrophil count (P less than 0.02). 4. Moreover, the mean in vitro erythrocyte haemolysis declined from an initial value of 64% to less than 2%, and there was a regression of skin lesions and alopecia with complete fur regrowth. 5. The amelioration of the conditions appear to be due to high circulating vitamin E which provided protection against oxidative stress, and the correction of membrane n-6:n-3 balance.

Alopecia↗
PubMed1991

The nutritional contribution to bovine spongiform encephalopathy.

Evidence that changes in feeding style alter the membrane fatty acid composition of ruminant tissue is presented here by comparing zoo giraffe with the same species from their natural habitat. The membrane changes seen are similar to those used experimentally to make animals susceptible to basic brain protein and encephalomalacia. Similar membrane responses have been noted in cattle. Use of animal protein and increased nitrogen in cattle feeds would lead to a relative deficiency of essential fatty acids in the cell membranes and hence reduced membrane stability. By analogy with crazy chick disease (nutritional encephalomalacia) and experimental encephalomyelitis in rats, the possibility that the changes in animals feeds would have depleted cattle tissue membranes and made them susceptible to BSE is discussed. The assumption being made is that the principle of a requirement of essential fatty acids for neural integrity and immune system function would apply to cattle as well as to other species.

Animal Feed↗
PubMed1990

Plasma vitamins A and E and hydrogen peroxide-induced in vitro erythrocyte haemolysis in common marmosets (Callithrix jacchus).

Plasma total lipid, cholesterol, all-trans retinol (vitamin A) and alpha-tocopherol (vitamin E) concentrations, and the susceptibility of erythrocytes to hydrogen peroxide-induced haemolysis in vitro were investigated in healthy laboratory-bred common marmosets (Callithrix jacchus). The concentrations of alpha-tocopherol and total cholesterol were similar to those of control human subjects. The mean lipid concentration was higher (P less than 0.025) and the retinol concentration lower (P less than 0.001) in the marmosets. The susceptibility of the erythrocytes of the marmosets to hydrogen peroxide-induced haemolysis was high, both in absolute value and relative to the controls. Changes in phospholipid and fatty acid composition might have rendered the red cells susceptible to oxidative stress.

Adult↗
PubMed1990

N-3 and N-6 phosphoglyceride fatty acids in relation to in vitro erythrocyte haemolysis induced by hydrogen peroxide in captive common marmosets (Callithrix jacchus).

1. Hydrogen peroxide-induced haemolysis (HPIH) was studied in the red blood cells of the common marmoset monkey (Callithrix jacchus) in relation to the composition of the membrane fatty acids. HPIH (%) was surprisingly high (mean 41% +/- 34; median 33.4%) and significantly different (P less than 0.001) from the corresponding value in healthy human subjects (mean 0.98% +/- 0.6; median 1.3%). 2. It was negatively correlated with 18:2n-6 (r = -0.76, P less than 0.001), 18:2n-6/20:4n-6 (r = -0.70, P less than 0.005) and 18:2n-6/22:6n-3 (r = -0.44, P less than 0.025) in the ethanolamine phosphoglycerides of the erythrocytes. 3. A shift in the n-6/n-3 balance in favour of the n-3 in the fatty acid composition of the membrane may have predisposed the red blood cells to haemolysis. 4. An increase in 22:6n-3, and a decrease of 20:4n-6 and 18:2n-6, may have been the result of feeding a diet containing fish products rich in long chain n-3 fatty acids.

Animals↗
PubMed1989

Plasma alpha-tocopherol, total lipids and total cholesterol in wild rockhopper, magellanic and gentoo penguins before and after moulting.

Post moult rockhopper penguins (Eudyptes crestatus) had significantly higher plasma alpha-tocopherol (vitamin E), total lipid and total cholesterol concentrations than their pre-moult counterparts. In the magellanic penguins (Spheniscus magellanicus) there were post moult increases in total lipid, cholesterol and alpha-tocopherol concentrations, but only the increase in alpha-tocopherol was significant. Plasma alpha-tocopherol, total lipid and total cholesterol concentrations in post moult gentoo (Pygoscelis papua) chicks were similar to those in non-moulting adult gentoos. Species differences in the levels of these nutrients in plasma may be due to differences in their dietary habits.

Animals↗
PubMed1989

The state of food production and nutrition in the developing countries.

The genesis of the problem of food production and nutrition of African, Asian and Central and South American countries can be traced back to the beginning of 'inter-continental trade' and the emergence of colonialism. Indigenous food patterns and social and economic orders that had evolved to befit the inhabitants and the environment were destroyed. A nutritional framework and an agricultural and economic policy designed to benefit the colonising nations were fostered. At present, millions of people in the developing countries suffer from endemic undernutrition and associated diseases. Famine is always present under the surface claiming families and individual hamlets and breaks through when the semblance of equilibrium between minimal food requirement for survival and supply is disturbed by natural or man-made disaster. Landlessness, an uneven distribution of wealth, overemphasis on cash-crop production, neglect of peasant agriculture in favour of unnecessary expenditure on military hardware and other misguided projects, and crop specialisation are some of the factors responsible for food shortage and undernutrition. Moreover, most of the staple foods of the developing countries are of low energy density and deficient in some essential nutrients. The cycle of undernutrition, hunger, disease and death can only be broken by instituting a well planned, peasant-orientated, integrated development programme based on self-reliance and self-sufficiency.

Developing Countries↗
PubMed1988

Serum alpha-tocopherol, all-trans retinol, total lipids and cholesterol in the black rhinoceros (Diceros bicornis).

1. Mean concentration of serum alpha-tocopherol (Vitamin E) in 28 free-living black rhinoceroses sedated during translocation in Zimbabwe was 1.92 (SD, 0.43) mg/l. 2. Alpha-tocopherol was not detectable (less than 0.15 mg/l) in five captive black rhinoceroses held at London Zoo. 3. Circulating levels of all-trans retinol (Vitamin A) were not different between the two groups. 4. The low level of alpha-tocopherol in captive rhinoceroses suggests a risk of acute haemolytic anaemia.

Anemia, Hemolytic↗
PubMed1988

Plasma retinol and alpha-tocopherol levels in captive wild animals.

1. The plasma retinol and alpha-tocopherol levels of a number of captive wild animals on defined vitamins A and E intake were determined. 2. In all the species examined they appeared to be low in relation to intake and as compared with recorded values of some domesticated species.

Animals↗