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Biomedical subjects

I Elmadfa

Publications and source records attributed to I Elmadfa.

At least 73 records · Page 4Linked to original sources
PubMed1990

[Antioxidant status after surgical stress].

Trauma and anaesthetics are responsible for local and general change in the organism. The characteristic changes in metabolism are caused by hormones. In addition, the increased glycogenolysis, gluconeogenesis, proteolysis and lipolysis are characteristic of this catabolic metabolism. Three groups (injured patients, patients with pulmonary disease, multiple trauma patients) showed an elevated lipid peroxidation as indicated by increased formation of TBA-reactive substances in the post-trauma or after surgery phase. The production of free radicals is supported by several stress factors. In this connection, the state of metabolism of the patients, several anaesthetics and the artificial respiration is very important. Enzymatic protecting systems (SOD, GSH-Px, Catalase) react to oxidative stress by positive adaptation. The non-enzymatic antioxidative systems (tocopherol, ascorbic acid, selen) are diminished, indicating an increased requirement.

Ascorbic Acid↗
PubMed1990

Neuroaxonal dystrophy associated with vitamin E deficiency in two Haflinger horses.

Neuroaxonal dystrophy and minimal diffuse degenerative myelopathy was diagnosed in two female full sibling, 1- and 2-year-old, Haflinger horses. Both animals developed slowly progressive ataxia from the age of 4 months. Clinical signs, which were more prominent in the hind legs, included hypermetria and dysmetria. Histological examination revealed neuroaxonal dystrophy characterized by spheroid formation, vacuolation, astrogliosis and lipofuscin pigment deposition in macrophages and neuronal perikarya. These changes were restricted to the gracilis and cuneate nuclei, nucleus of the solitary tract, nucleus intermediomedialis in the sacral and the seventh segment of the cervical spinal cord and Stilling-Clarke's column in both horses and the medial vestibular nucleus in the older horse. Both diseased Haflingers had significantly reduced serum alpha- and gamma-tocopherol values. No significant alteration in serum total lipid concentrations and serum selenium values were observed. It is likely that the condition has a familial hereditary basis. It is unclear whether there is a link between the observed neuroaxonal dystrophy and vitamin E deficiency and further investigations are warranted.

Animals↗
PubMed1989

[The transformation of gamma-tocopherol to alpha-tocopherol in the animal organism; a generational study in rats].

The biosynthesis of alpha-tocopherol, the most effective vitamer among the vitamin E-group, is found only in higher plants and microorganisms. Due to the lack of the shikimate pathway, animals are not able to synthesize alpha-tocopherol. Also not found is a whole enteral synthesis; only the conversion of dimethyletocol to trimethyletocol seems to be possible. Using four generations of rats, we sought to determine: Is a transformation of gamma-tocopherol to alpha-tocopherol in the animal body possible? Are there any differences in the transformation rates in organs, tissues, or in the entire body along the generations? Does gut flora play any role in the conversion of gamma-tocopherol? Is it possible to increase the efficiency of the transformation by supplying additional CH3-groups? Wistar rats were fed a semisynthetic basal diet, supplemented with 78.8 mg DL-gamma-tocopherol/kg in the first three generations (F1-F3). In the fourth generation (F4), some of the animals were fed a vitamin E-free diet and gamma-tocopherol (approx. 1.5 mg on alternate days) was injected s.c. Two other groups of animals received the basal diet containing additional methionine (0.25%) or choline (0.45%), as well as gamma-tocopherol (as in F1-F3). alpha- and gamma-tocopherol were analyzed by HPTLC in the whole body and in serum, liver, heart, lung, gut, gonads, and feces. The ratio of alpha-/gamma-tocopherol (micrograms/micrograms) as transformation rate and vitamin E-biopotency (microgram alpha-tocopherol equivalents/g) were calculated. Growth and fertility were normal until the fourth generation; no abnormal developments could be recognized. alpha-tocopherol was found in the whole-body as well as in all tissues and organs. In the whole-body, vitamin E-biopotency decreased 25-70% in F2 and F3. On the other hand, the increase of the transformation rate of gamma- to alpha-tocopherol amounted to 23% (F2) and 168% (F3). Highest conversion rates were found in F2 and F3 for feces, followed by gonads and lungs; the lowest rates were found for serum and liver. Due to the s.c. injection of gamma-tocopherol, feces showed a four-times lower transformation rate in F4 than in F3. There was an increase in heart, gut, lung and serum for both transformation rate and vitamin E-biopotency. These parameters could be improved also by the additional supplements of methionine and choline. Both methyl-group-donators revealed nearly the same positive effect. The results show that the animal organism can adapt to gamma-tocopherol supply over generations.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Effects of an intravenous application of dl-alpha-tocopheryl acetate on tocopherol status in man.

The effects of intravenously administered dl-alpha-tocopheryl acetate on the plasma, erythrocyte and thrombocyte vitamin E levels were investigated in male subjects. 110 mg dl-alpha-tocopheryl acetate were applied as a single dose in the form of a rapid infusion. After 60 min, 89% of the dl-alpha-tocopheryl ester had been eliminated. The vitamin E ester injected was hydrolyzed and was detected in the plasma and the erythrocytes as free alpha-tocopherol. No significant change in the tocopherol concentration was observed in the thrombocytes. The results show that intravenously applied, esterified tocopherol is hydrolyzed relatively rapidly in the plasma, leading to an increase of free alpha-tocopherol content in the plasma and erythrocytes. The ratio of erythrocyte/plasma tocopherol 2 h after injection was 61% higher than the initial value; after 24 h the elevation was still 36%.

Adult↗
PubMed1988

Effect of dietary linoleic acid and essential fatty acid deficiency on resting metabolism, nonshivering thermogenesis and brown adipose tissue in the rat.

Rats were fed a diet either deficient (0.05%) in essential fatty acids (EFA), or providing 4% (control) and 10% (surplus) of the total energy intake in the form of linoleic acid. All diets were isoenergetic and provided 13.9% of the energy as fat. The rats were kept at 29 or 5 degrees C. Growth and food intake of rats fed linoleic acid surplus at either temperature for 10 wk were not different from that of controls; basal metabolism, norepinephrine-induced nonshivering thermogenesis (NST) and thermogenic variables in the brown adipose tissue (amount of mitochondria and mitochondrial uncoupling protein) also were not different. The effects of EFA deficiency were drastically enhanced in the cold: After 10 wk of consuming a diet low in EFA at 5 degrees C, the body weight of rats was 75% of that of controls (87% at 29 degrees C); the food intake was 135% of controls at 5 degrees C (120% at 29 degrees C). The resting respiration in deficient rats was 125% of controls at 5 degrees C (110% at 29 degrees C); body temperatures as low as 35.1 degrees C were measured in deficient rats after 3 wk at 5 degrees C; the cold tolerance of the rats was significantly diminished (30% died within 3 wk at 5 degrees C), thus emphasizing the essential role of dietary EFA during cold stress. Norepinephrine-induced NST and the thermogenic parameters in brown fat were not influenced by EFA deficiency.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue, Brown↗
PubMed1987

[Effect of particle size and emulsifier on pharmacokinetic values of a parenterally administered fat emulsion].

To evaluate pharmacokinetic data during parenteral application of a fat emulsion a controlled study in healthy volunteers was performed. Another aim of the study was to investigate whether these kinetics could be changed by modification of the emulsion. For this purpose, 10 male medical students--free of any metabolic disorders--received modified batches of one fat emulsion (Lipovenös), differing with respect to particle size or emulsifier. The emulsions were applied using a pump-controlled continuous infusion technique. The dosage was calculated according to body weight: 0.1 g/kg B.W./h. There was a 7-10 day interval between one application and the following study period, again using the same volunteers. Thus every volunteer served as his own control. Routine laboratory parameters as well as parameters relating to fat metabolism were measured. While routine laboratory parameters were not statistically different between the groups, pharmacokinetic data showed differences according to the batches used. Highest triglyceride and free fatty acid levels i.s. were present after application of the emulsion with low medium particle size, while lowest levels were found after increasing the particle size to 380 nm. In addition, it could be documented that an increase in medium particle size resulted in higher elimination rate, transfer and pool size. The modified emulsifier led to an additional increase of these effects, thus inducing beneficial metabolic profiles. The results of the present investigation might perhaps enable us to adjust the profile of future fat emulsions, with the aim of optimizing or restoring metabolic hemostasis.

Adult↗
PubMed1986

[Effect of vitamin E on experimental inflammation in rats].

Besides other mediators like prostaglandins, kinins and histamine, oxygen radicals potentiate inflammations. Vitamin E as natural antioxidant could scavenge radicals produced during an inflammation and therefore reduce the inflammatory response. In experiments with male Wistar rats maintained on a diet deficient in or supplemented with vitamin E for 6 weeks the influence of the administration of DL-alpha-tocopherol on the inflammation of the right hind paw was tested. The irritation produced by injection of Freund's complete adjuvants was observed for 21 days. Measuring the thickness of the paw and the activity of acid phosphatase in the paw tissue there was no difference in the intensity of inflammation among the control and the vitamin-E-deficient diet groups. The supplementation with a pharmacological dose of tocopherol (324 mg DL-alpha-tocopherol/100 g food) had no effect on the inflammation of animals with different vitamin E supplements. Differences in the antioxidant status (contents of tocopherol and malondialdehyde in several organs, activity of creatine kinase in plasma) among the groups were mainly linked to the various tocopherol supplies. The irritation increased the lipid peroxidation in liver mitochondria and the activity of creatine kinase in the plasma. The data show no influence of vitamin E on this kind of inflammation.

Acid Phosphatase↗
PubMed1986

[Effect of alpha- and gamma-tocopherol as well as cholesterol on lipid peroxidation].

For a period of 15 weeks growing rats were fed low fat diets containing equimolar doses of alpha- and gamma-tocopherol (180 and 174 ppm) as well as mixtures of alpha- and gamma-tocopherol (3:1; 1:1; 1:3) without cholesterol or with 1% cholesterol. The influence of these supplements on lipid peroxidation and tocopherol retention in the liver were investigated. The tocopherol status was estimated by measuring the activities of creatine kinase and transaminases (GOT, GPT) in plasma as well as by in vitro hemolysis of erythrocytes. The in vitro hemolysis rate was only lowered by alpha-tocopherol and the mixtures of alpha- and gamma-tocopherol. In response to lipid peroxidation in the liver, alpha-tocopherol was the more efficient antioxidant, whereas gamma-tocopherol was more efficient in the diet. Cholesterol had a lowering effect on lipid peroxidation in vitro and in vivo; cholesterol in combination with alpha-tocopherol had a stabilizing effect on the erythrocyte membrane. Moreover, there was a positive effect of cholesterol on tocopherol retention in the liver. The biological activity of gamma-tocopherol in relation to alpha-tocopherol was calculated according to the test criterium; it ranged from 22 to 100%.

Alanine Transaminase↗
PubMed1984

[Concentrations of bile acids in serum, urine and feces in patients with gastrointestinal diseases. Effect of peptide diet in comparison with a normal diet].

The influence of a peptide diet on the concentration of bile acids in serum, urine and stools of patients with gastro-intestinal diseases was investigated. The concentration of bile acids in the samples from the patient group treated with a peptide diet showed no significant differences to the control group, who received a normal diet. Therefore, it can be ascertained, that a peptide diet, in comparison to a normal diet, has no reducing or stimulating effect on the composition and concentration of bile acids in serum, urine or stools; both parameters, i.e. the composition and concentration of bile acids, remain unchanged.

Bile Acids and Salts↗
PubMed1984

The effect of essential fatty acid deficiency on basal respiration and function of liver mitochondria in rats.

Rats were fed a diet poor (0.05%) in essential fatty acids (EFA) with hydrogenated coconut oil as fat component, or a control diet containing 4% of the total energy intake in the form of linoleic acid. Effects of dietary EFA deficiency were investigated during a period of 2-30 weeks. Growth retardation becomes significant after 4 weeks of deficiency and attains about 25% when the deficiency is maintained for longer than 12 weeks. Respiration, body weight and age of EFA-deficient rats and controls are in a nonlinear relationship. Basal respiration in relation to the body weight is significantly increased by EFA deficiency; it is unchanged when related to total animals under the employed experimental conditions. Oxidative phosphorylation in isolated liver mitochondria is unaffected by EFA deficiency, i.e., the increased metabolic rate of EFA-deficient rats, related to the body weight, cannot be explained from impaired functional integrity of the inner mitochondrial membrane. Respiratory chain enzyme activities in mitochondria from heart and skeletal muscle and specific amounts of mitochondria in these tissues are unchanged by EFA deficiency.

Animals↗
PubMed1984

Relative bioactivity of alpha- and gamma-tocopherol calculated from respiration parameters in rat liver mitochondria.

In experiments with male wistar rats the influence of dl-alpha-tocopherol as well as dl-gamma-tocopherol on both the respiration of liver mitochondria and membrane lipid peroxidation has been investigated. For a test period of 8 weeks the animals were fed isoenergetic diets containing either no vitamin E or 46 mg d-alpha-tocopherol equivalents/kg diet as dl-alpha-tocopherol (60 ppm) or dl-gamma-tocopherol (480 ppm). The diets contained 6% of a synthetic triglyceride mixture rich in polyunsaturated fatty acids (about 60%). The measurements of the P/O ratios and corresponding respiratory control index (RCI) values for several substrates (alpha-ketoglutarate, malate/glutamate, succinate) indicated that under vitamin E-deficient conditions the mitochondria showed an increased respiratory intensity accompanied with an elevated lipid peroxidation. The oxidative phosphorylation itself was not affected. These deficiency symptoms could be normalized by the applied amounts of both tocopherols. In this respect dl-gamma-tocopherol showed a more distinct bioactivity than previously proposed. Based on the investigated parameters we calculated for dl-gamma-tocopherol an average bioactivity of 28% compared to that of dl-alpha-tocopherol.

Animals↗
PubMed1983

[Nutrition and capacity for concentration in automobile drivers].

One of the most important food components for the ability to concentrate is protein because certain amino acids are precursors of neurotransmitters, e.g. serotonin from tryptophan. There is a close relation between tryptophan content in the diet, serotonin biosynthesis in the brain and food intake. While lack of carbohydrates causes a symptomatic hypoglycemia which leeds to decreases in different functions and performances (e.g. memory and concentration, orientation, critical evaluation of environmental influences), glucose load does not mean an increased performance. In this respect dietary fats and minerals have not been investigated, some vitamins, e.g. thiamin, influence the functions of the nervous system. With coffee and caffeine containing beverages a drop of performance can be compensated for only a short time at the expense of energy reserves. Under the moderate influence of alcohol the function of nervous cells is markedly affected. In connection with medicine this negative effect is aggravated. After coffee and alcohol consumption events are subjectively experienced on quite a different level than can be objectively measured; misleading estimations are the consequence. A high meal frequency with small meals stimulates the serotonin biosynthesis and seems to reduce fatigue.

Attention↗
PubMed1983

[Development and testing of protein mixtures based on blood and collagen].

Using the results of the chemical amino acid analyses of the unconventional proteins blood, collagen and wool and the conventional proteins soya, maize and casein, protein mixtures were developed. The quality of the protein mixtures was estimated in feeding experiments with growing male Sprague-Dawley rats and expressed as protein efficiency ratio (PER). Different blood parameters and the weight of some organs were also recorded. Blood, collagen and wool protein are very poor in different essential amino acids, therefore their quality is very low, it can however be significantly improved when they are fed in mixtures with other animal or plant proteins of higher quality. In mixtures of three components only containing blood (10--40%), collagen (10--25%) and casein (50 to 70%) the deficit in the content of essential amino acids cannot be compensated. Rats fed with such diets showed, however, decreased food intake and depressed growth. The relative PER values of those mixtures were 44--69% of that of casein. The best supplementing effect on the imbalanced amino acid patterns was achieved when the protein mixture was developed from 4 or 5 different proteins. The quality of these five-component-mixtures amounted to 94--100% of that of casein. In these mixtures the percentage of casein in the protein mixture amounted to only 35% and soya or maize to 15%. Exactly 50% of the protein supply could be derived from hydrolysates of the unconventional proteins blood, collagen and wool.

Amino Acids↗
PubMed1983

[Evaluation of the quality of protein mixtures based on collagen and blood. Comparison of biological and chemical evaluation criteria in rats].

The quality of protein mixtures on the basis of blood protein, collagen, wool and other proteins was tested using different chemical and biological criteria of protein evaluation. Before mixing the single proteins were hydrolysed enzymatically by means of acid or alkaline proteinases. In this study the influence of both hydrolysis processes on the bioavailability of the protein mixtures was also considered. The N-balance experiments were carried out with weanling Sprague-Dawley rats in groups of n = 6 animals each. The estimated BV's showed that the protein quality was significantly affected by both hydrolysis procedures especially when the hydrolysates were compared with the non-hydrolysed protein components. The BV's also showed that the quality of all mixtures of protein hydrolysates was less than that of casein (reference protein) and the availability of the alkaline hydrolysed proteins better than that with acid proteinase treated proteins. This result could be confirmed by the calculated chemical criteria E/T- and E/N-ratios, EAA-Index and Arnould-Index. The results of the growth-criteria PER, NPR and RNV did neither correspond with each other nor they were of good agreement with N-balance based BV and NPU.

Amino Acids↗
PubMed1983

[Significance of nonsaponifiable constituents of dietary fats on the bioactivity of vitamin E].

In experiments with male Wistar rats the influence of the non-saponifiable constituents of dietary fats: dl-alpha-tocopherol (60 ppm), dl-gamma-tocopherol (480 ppm), ubiquinone (96 ppm) and beta-sitosterol (3035 ppm) on the tocopherol status was investigated, considering the fatty acid composition of the tested fats. For a test period of eight weeks the animals were fed isoenergetic diets containing three types of dietary fats: corn oil (60% PUFA), a kind of "stripped corn oil" (60% PUFA) and butter (nearly 5% PUFA). Independent of the PUFA-content of the diet, the tocopherol supplementations were able to stabilize the erythrocyte membrane; the calculated hemolysis rates were about 2%. The absence of tocopherols in the diets ("stripped corn oil", butter) caused an increase of the hemolysis rate up to 70% after two weeks. The original amounts of tocopherols in corn oil tended to minimize the hemolysis. Ubiquinone and beta-sitosterol did not reduce the hemolysis rates when they were applied without tocopherols. With respect to creatine-phosphokinase activity, creatine and creatinine excretion the results were similar. Plasma and erythrocyte levels of alpha- and gamma-tocopherol were determined in all groups and discussed in connection with the other examined parameters of tocopherol status. The ultimate result of this experiment is that the content of tocopherols in dietary fats is not always adequate to keep vitamin E status normal, especially if polyunsaturated fatty acid content is high in the diet. Reflecting the vitamin E adequacy of dietary fats, not only alpha-tocopherol but also gamma-tocopherol should be much more considered than previously.

Animals↗