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Biomedical subjects

W Feldheim

Publications and source records attributed to W Feldheim.

At least 37 records · Page 2Linked to original sources
PubMed1988

Size and composition of liver vitamin A reserves of human beings who died of various causes.

Postmortem livers from 77 "normal" persons, 37 patients with neoplastic disease, 10 subjects with liver insufficiency, and 7 infants were analysed for free and esterified retinol. The average concentrations of total vitamin A for the members of each group were 597, 551, 289, and 162 micrograms/g wet liver, respectively. Compared with corresponding control values, both cancer victims and patients with liver disease had significantly lower hepatic vitamin A levels. With regard to the composition of the liver vitamin A reserves, our results show that approximately 97% of this vitamin was present as retinyl ester. Additionally, minute amounts of retinol were also found in most of the liver specimens analysed. In "normal" subjects the major ester fraction recovered was palmitate/oleate followed by stearate and myristate/linoleate. By contrast, the second most abundant fatty acid in the retinyl ester fraction of cancer victims was myristic/linoleic acid together with significantly smaller quantities of stearic acid. In tissue samples obtained from patients with liver disorders, however, the myristate/linoleate fraction was increased and therefore nearly equal amounts of both retinyl stearate and myristate/linoleate were present.

Cause of Death↗
PubMed1987

[Quantitative determination of vitamin A in liver and liverwurst using high pressure liquid chromatography (HPLC)].

Samples of liver sausage and liver tissue from slaughtered animals were analysed for pre-formed vitamin A. A sensitive reversed phase HPLC method with fluorescence detection was used to determine the amount of free and esterified retinol in extracts of these samples. Under our chromatographic conditions retinyl myristate and linoleate run together as do retinyl palmitate and oleate. The contents of all forms of vitamin A were expressed in milligrams of all-trans retinol per 100 g wet weight. The average concentrations of total vitamin A for turkey, pig, calf, beef, and chicken liver were 42.31, 38.15, 22.74, 14.98, and 13.22, respectively. In addition to these differences, the fatty acid composition of liver retinyl esters, as well as the amount of retinol, also varied considerably among species. Approximately 95% of the hepatic vitamin A was present as retinyl ester with retinyl palmitate/oleate as the main ester fraction. The second most abundant fatty acid in the retinyl ester fraction of calf, beef, and chicken liver was stearic acid followed by myristic/linoleic acid. An increment of retinol, however, was also found in these tissue samples. By contrast, in turkey liver the retinol fraction was increased and therefore both retinyl stearate and retinol were present in nearly equal amounts, whereas the retinyl ester fatty acids from pig liver contained relatively more myristate/linoleate and less stearate than those from liver of the other domestic animals (apparently a hallmark of pig liver). The retinol and retinyl ester pattern present in liver sausage was similar to, but not identical with, that of pig liver.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Studies on the tocopherol status in blood serum of premature babies and infants.

The level of naturally occurring tocopherols in blood serum of 88 preterm infants, aged from birth to 2 years, was determined by the high performance liquid chromatographic (HPLC) method using fluorescence detection. In 11 cases, patients were assayed for their tocopherol status in longitudinal studies, receiving known amounts of vitamin E supplements orally and/or parenterally. No correlation was found between serum alpha-tocopherol level and gestational age nor birth weight. All preterm infants receiving the vitamin E preparation showed an average serum tocopherol content of more than 0.5 mg/100 ml. The highest alpha-tocopherol concentration registered during vitamin E therapy was 3.28 mg/100 ml. Infusion of Intralipid, a product derived from fractionated soybean oil, caused a significant increase of gamma- and delta-tocopherol in blood serum. The half-life of delta-tocopherol in serum was calculated to be about 24 hours.

Administration, Oral↗
PubMed1985

Comparison between three fluorometric micromethods for determination of vitamin A in serum.

Three common micromethods for vitamin A1 determination were applied to blood, and compared with each other. Methods under investigation were: silicic acid column technique described by Pollack et al [16], HPLC procedure published by de Ruyter and de Leenheer [6, 7] and correction formula method according to Thompson et al [20]. The serum levels of vitamin A were measured in 51 fasting individuals. The average overall agreement was 104% and 116% of the HPLC value for the silicic acid column technique and for the correction formula method, respectively. The mean values obtained by the three methods do not differ significantly. Using these techniques simultaneously, however, in some cases serum values for the same sample show wide differences. Although vitamin A is usually present in biological samples both as retinol and as retinyl esters, the simple correction formula method does not distinguish between them. Their separate estimation, however, can be achieved by different chromatographic procedures. The HPLC method therefore used offers several advantages over the described silicic acid column technique. This technique includes fluorescence detection and provides a rapid and simple estimation of retinol and retinyl palmitate levels using only 180 microliter serum. For these reasons, the HPLC assay is suggested for routine determination of vitamin A in blood.

Adult↗
PubMed1985

Serum lipoproteins protect isolated erythrocytes against retinol-induced haemolysis.

Under physiological conditions no evidence of haemolysis caused by hypervitaminosis A or vitamin A1 therapy was noted so far in the literature. Nevertheless, previous studies have demonstrated that isolated red blood cells were readily lysed by retinol and structurally related compounds [8]. These data are compatible with the existence of serum components with binding-properties comparable to that of retinol-binding protein. We therefore decided to identify additional acceptors for retinol in human serum. It was shown, that serum lipoproteins and to a lesser extent albumin protect red blood cells for the lytic effect of retinol. The amount of lipoproteins, serum, bovine serum albumin and lipoprotein-deficient serum needed to inhibit retinol (9.6 micrograms/ml) by 50% were 3, 58, 325, 1900 micrograms protein/ml respectively. Increasing their concentration in the incubation mixture results in a decrease in the rate of haemoglobin release and at last complete protection was achieved. Altogether, the results suggest that lipoproteins bind retinol and render it therefore non-haemolytic like retinol-binding protein. Furthermore, the latter indicates that lipoproteins act as carriers for vitamin A given parenterally, which one might expect since the lipoproteins are capable of transporting hydrophobic molecules.

Biological Transport↗
PubMed1984

[Determination of the tocopherol content of the nonsaponifiable fraction of lupine oil (L. mutabilis)].

The content of individual tocopherols was determined in 11 samples of lupine oil (L. mutabilis) from Peru by GC- and HPLC-procedures. The main component is gamma-tocopherol (42-69 mg/100 g oil); alpha- and delta-tocopherol were found in traces (0.1-0.7 mg/100 g oil). The pretreatment of samples, necessary for the GC-methods leads to tocopherol losses of 30% on average, this loss is mainly caused by the saponification of the samples. The tocopherols are predominantly present in an unesterified state.

Chromatography, Gas↗
PubMed1984

[Effects of various methods on the determination of dietary fiber and available carbohydrates on the calculation of the energy content of bread].

The dietary fiber content of German breads was determined by two different methods. With a modified NDF-method 60% of total dietary fiber (determined by an enzymatic-chemical procedure) are detected. For estimation of the physiological fuel value the main components of breads were determined by analysis. In addition, the carbohydrates were determined by difference, using various methods of calculation. For the estimation of the caloric value, different calorie conversion factors are used.

Amylases↗
PubMed1983

[Caloric value and dietary fiber content of cereals, flours and breads].

A new method for the determination of the caloric values of foods is proposed. To date it had been suggested that with an increase in the dietary fiber content of foods the intestinal absorption of proteins and fats is reduced. This has to be revised in the light of recent experimental results. The new method leads to higher energy values for fats and proteins whereas for carbohydrates lower figures are obtained. This leads to considerable deviation in the energy content of foods from the values in present tables, especially for foods rich in dietary fiber.

Bread↗
PubMed1982

Serodiagnosis of opisthorchis viverrini infestation by an enzyme immuno-assay.

The application of an enzyme immuno-assay is evaluated with regard to antibody reactivity to Opisthorchis viverrini antigen in 20 Laotian patients and control groups including patients with other helminthic infections as well as persons without parasitic infestation. It is concluded that the enzyme immuno-assay indicates infection by O. viverrini. In certain circumstances, which are discussed, the test may serve for valuation of treatment.

Adult↗
PubMed1981

High efficacy of praziquantel in the treatment of 22 patients with Clonorchis/Opisthorchis infections.

In a prospective clinical study, the efficacy of praziquantel in the treatment of 22 patients with Clonorchis/Opisthorchis infections was investigated. The dose regimen was 90 mg per kg bodyweight, divided into three equal doses given on consecutive days. Parasitological, clinical, routine haematological and biochemical parameters were followed up for twelve months. Twenty patients (91%) had no detectable egg excretion in the feces or duodenal fluid after one treatment only. Two patients required repeated treatments and a different dose regimen. No serious side effects were observed. Praziquantel proved to be a safe and effective drug for therapy of Clonorchis/Opisthorchis infections.

Adolescent↗
PubMed1980

[A method for the determination of tartrazine in candies and pudding mixes (author's transl)].

The use of food additives is viewed increasingly from a critical point of view. In some countries, stronger regulations with limitations for the use of synthetic coal-tar dyes are planned or exist already. For that reason, a quantitative method for the determination of tartrazine (E 102) is needed for supervision of food quality. A method is described using as its steps extraction of the dyestuffs from the samples, chromatography on silicagel plates and automatically recorded densitometry. In candies amounts of up to 285 mg tartrazine/kg and in pudding mixes up to 1223 mg tartrazine/kg were found.

Azo Compounds↗
PubMed1977

[A quantitative micromethod for the caffeine determination (author's transl)].

A combined procedure with thin-layer-chromatography and densitometry is described for the quantitative estimation of caffeine in biological material. This method is applicable in the nanogram range. Test samples of less than 100 microliter may be used. The samples (capillary-blood) are extracted with the same volume of chloroform. Caffeine is separated from interfering compounds by thinlayer-chromatography. Commercial silica-60-plates with chloroform/acetone (9+1; v/v) as solvent are used. The running time is about 30 min. The quantitative densitometric determinations are performed in the remission mode at 273 nm. In the range from 10 to 60 ng/spot the calibration curve is linear. Accurate quantitative data will be obtained even at concentrations of 1 mg/l caffeine. The detection limit is at about 0.1 mg/l.

Caffeine↗
PubMed1976

[Guar II. Feeding Trials with Animals].

Feeding trials with guarbeans or its protein- or carbohdrat-rich fractions with cattle, poultry and rats are briefly summarized. The protein fraction of the bean contains toxic substances of unknown structure. The toxic effect is diminished by heating. In case of addition of the carbohydrate-rich fractions of the bean in the feeding experiments depression of growth is observed probably in connection with the bad utilization of the galactomannan or the decrease of fodder consumption due to the expanding volume of the fodder in the gut.

Animal Feed↗
PubMed1975

[Studies on tea. I. Contents of mercury, lead, and cadmium in tea leaves and tea decoctions (author's transl)].

In a survey on 25 teas from different countries for toxic trace elements the concentration of lead was found to be up to 3.08 ppm. of Cadmium up to 0.012 ppm, and of Mercury up to 3.0 ppm, respectively. The actual concentration in the tea decoction is much lower as in the tea leaves, for lead up to 0.02 ppm and for Cadmium below the sensitivity of the method. It was recommended to set the tolerable values for these elements in the tea leaf higher as recommended for the direct consumed foodstuffs or to consider the final concentration in the tea decoction only.

Cadmium↗