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Biomedical subjects

K Pietrzik

Publications and source records attributed to K Pietrzik.

At least 55 records · Page 3Linked to original sources
PubMed1989

[Bioavailability study of micronutrients].

Bioavailability studies of micronutrients (vitamins, minerals) from different food stuffs, as well as from pharmaceutical preparations are of great importance for the calculation of nutrient intake and/or the evaluation of the therapeutic value. In practice, bioavailability studies are not generally performed on a standardized level. For this reason basic criterions are presented and discussed. Finally, the investigation of the bioavailability of folate is demonstrated by an example. The parameters investigated are: the maximal concentration (cmax), the time to reach this maximum (tmax), and especially the bioavailability ratio determined from the area under the curve (AUC) after administration of the folic acid containing test and reference preparation. The results indicate that 5-formyl-tetrahydrofolic acid given in the tested form has nearly the same bioavailability (ratio: 1.02) as folic acid (pteroylmonoglutamic acid) in aqueous solution.

Adult↗
PubMed1989

[The importance of folic acid substitution in pregnancy].

Folate deficiency is very common in Germany. In the average 15% of different groups of people (children, adolescents, adults, the elderly) show biochemical resp. haematological alterations corresponding to folate deficiency. In pregnancy there is a much higher risk to develop folate deficiency because of a drastic increase in folate requirement. This is mainly due to the fetoplacentar folate transfer and even an ideal diet can't prevent folate deprivation during pregnancy. An inadequate supply situation before and during pregnancy might be a high risk for developing deficiency symptoms not only for the mother but especially for the foetus. Though the consequences of folate deficiency are very well known, nothing has happened in the past concerning the estimation of folate status in pregnant women. Information about an ideal diet in pregnancy and perhaps folate supplementation are therefore desirable.

Female↗
PubMed1985

Pantothenic acid deficiency as a factor contributing to the development of hypertension.

In endemic pantothenic acid deficiency of some Japanese populations, increased occurrence of hypertension has been described. However, all attempts to produce hypertension experimentally by means of pantothenic acid deficiency have failed up to now. As a consequence, the observations made in Japan have largely been ignored. In this paper, pantothenic acid deficiency will be shown to be a factor in the experimental origin of hypertension due to adrenal regeneration.

Adrenal Glands↗
PubMed1985

[Evaluation of the folacin status in children with regard to the cobalamin and iron status. 1. Changes in the differential blood picture as a function of the vitamin and ferritin levels of the serum vs. erythrocytes].

The biochemical data concerning the evaluation of the folacin status in children are insufficient, as there are no biologically based borderlines available. In a study with 165 children between 1 and 15 years we looked for serum and erythrocytic folate concentrations and correlated the results with morphological alterations in the blood picture (lobe average of the neutrophilic granulocytes). As cobalamin and iron status influences different folacin depending parameters we estimated the vitamin B12- and ferritin concentration in serum as well. In our study neither the iron nor the cobalamin status influenced the blood picture and the blood folate concentrations. That's why all samples could be taken for the final evaluation. It could be demonstrated that folacin serum levels below 4.0 ng/ml respectively erythrocytic concentrations below 250 ng/ml correspond with an increasing lobe average above 3.5 compared with normal values ranging between 2.8-3.5. These biologically based borderlines were comparable between the different age groups. On the basis of these data it is possible to assess the duration and severity of folacin deficiency in children.

Adolescent↗
PubMed1985

[Evaluation of the folacin status in children with regard to the cobalamin and iron status. 2. Incidence and severity of folate deficiency].

In a study with 165 children the folate, cobalamin and iron status was investigated by biochemical and haematological methods. On the basis of biologically based borderlines it could be demonstrated, that 15% of the children showed folate deficiency in a progressive state. This means that low serum resp. low erythrocytic folate concentrations correlated with alterations in the blood picture (lobe average of the neutrophilic granulocytes). Especially children in the age of puberty (11-15 years) are to be regarded as vulnerable; 30% of this group show deficiency symptoms whereas in very young children (1-5 years) only in 10% the supply situation is insufficient. The folate status in pupils (6-10 years) is comparable to adults (15% deficient). As cobalamin and iron status may influence folate depending parameters the status of these nutrients was estimated, too. Cobalamin deficiency was not detectable in any case. Though the iron supply situation was not adequate in all cases, interactions with the folate depending parameters could be excluded.

Adolescent↗
PubMed1985

[Assessment of the folate supply in children with regard to cobalamin and iron maintenance. 3: Modification of the supply status by various diseases].

Assessment and Evaluation of the Folacin Supply in Children with Respect to the Cobalamin- and Iron Status - 3rd Communication. On the basis of biochemical data concerning folate-, cobalamin- and iron status of healthy children (n = 165) we estimated the supply situation in 258 children with different diseases. Patients suffering from celiac disease showed in a high frequency symptoms of a "subclinical-manifest" folate deficiency. In spite of folate therapy in Crohn's disease the supply situation was as bad. The supply situation of the controls and infected children was comparable. Anticonvulsant (folate antagonists) therapy had a significant influence on the folate status demonstrated with radioimmunological technique. In contrast to these results patients suffering from phenylketonuria had exceptionally better folate values than the controls. Obviously the vitamin content of the diet products exceeds the recommendations.

Adolescent↗
PubMed1981

[Radiological investigations of cobalamin supply with regard to folate status (author's transl)].

In a study with 307 volunteers we estimated the cobalamin status by radiochemical (plasma cobalamin) and haematological (lobe average of granulocytes) methods. As there is a close biochemical connection between the folate and cobalamin metabolism (methyl-tetrahydrofolate-trap hypothesis) we additionally determined the plasma- and erythrocyte folate levels in 307 volunteers by radioimmunoassay. Further metabolic studies in humans showed that a cobalamin concentration of less than 160 pg/ml indicates a deficient supply. In the present study 6% of the men and 8% of the women showed an inadequate alimentary supply.

Erythrocytes↗
PubMed1980

[Investigation or oral substitution of iron and folic acid (author's transl)].

In a study of apparently healthy volunteers (5 male, 5 female) the bioavailability of iron and folacin was calculated using Tardyferon¿ resp. Tardyferon-Fol¿ as test substances. Blood samples for serum iron and folacin level determinations were obtained before and 1/2, 1, 2, 4, 6 and 8 hours after dosing. Because of the diurnal fluctuation of serum iron and folate levels, baseline levels were obtained at the corresponding 0, 1/2, 1, 2, 4, 6 and 8 hours one week prior to the study. Serum iron and folacin levels above the baseline values and the area under the curve were calculated. The data suggested a good bioavailability of the tested substances. The folacin absorption after a single dose of 0.35 mg produced a maximal serum concentration of mean = 28 ng/ml. Twice the dose resulted in a maximum of serum folacin level of mean = 51 ng/ml. The oral administration of 80 mg Fe2+ resp. 160 mg Fe2+ resulted in a significant increase of the serum iron levels, too.

Administration, Oral↗
PubMed1980

[Biochemical and hematological parameters for the estimation of folate status in man. 3. Importance of formiminoglutamic acid excretion in the urine in comparison to other measurements].

In a study on 250 industrial workers the amount of the formiminoglutamic acid excretion in urine was measured by an enzymatic spectrophotometric method. For the estimation of the folacine status the vitamine concentration in serum and erythrozytes was determined as well as the segmentation of the neutrophilic granulocytes. As shown in previous studies these parameters indicate the degree of folate supply. A correlation between the FIGLU excretion in urine and other folate dependent parameters could not be demonstrated. Criterial to judge the folate supply are the radioimmunological determination of folacine concentration in serum and erythrocytes as well as the estimation of the segmentation of the neutrophilic granulocytes.

Female↗
PubMed1980

Studies on the distribution of (1-14C) pantothenic acid in rats.

The distribution of (1-14C) pantothenic acid was studied in two different experiments with rats. Single dose kinetics were carried out over a period of 168 hours. In this experiment it could be shown that besides the urinary and faecal output a third route of excretion exists: the respiratory pathway. The tissues with the highest retention capacity were the kidneys, pituitary gland, heart, muscle, liver and the adrenal glands. In a second experiment - performed as steady state study, lasting 35 days - during the investigated period and finally in the steady state the above mentioned tissues showed the highest affinity for pantothenic acid, indicating an intensive metabolism of this vitamin. These results are discussed, especially towards pantothenic acid and acetyl coenzyme A-depending functions.

Animals↗
PubMed1978

[Biochemical and hematological measures for determination of folate status in humans. 1. Relation between serum folate and segmentation of neutrophil granulocytes].

In a study on 130 student volunteers the segmentation of neutrophil granulocytes was measured. The serum folate concentration was used as biochemical reference. Both parameters indicate the state of folate supply or the degree of folate deficiency, respectively. Considering the haematologic response as an objective criterion only 71% of the examines showed an adequate folate status. 11% were found "deficient" and 18% were in a marginal state of folate supply. This result was confirmed by repeating the experiment. Further studies are to include folate concentration of erythrocytes and urine concentration of formiminoglutamic acid.

Adult↗
PubMed1978

[Biochemical and hematological measures for determination of folate status in humans. 2. Comparative determination of folate in blood and in erythrocytes].

Criteria to judge the folate supply have been evaluated in previous studies. The present study is examining parameters to estimate the degree of folate deficiency. Serum folate levels and erythrocyte folate concentrations were measured in 116 volunteers (patients). The erythrocyte folate is to a large extend independent of exterior supply and is lowered only in severe chronic deficiency. Low levels of erythrocyte folate indicate longstanding undersupply. Our experiments show that folate concentration of greater than 250 ng per ml erythrocytes indicate adequate supply. Concentrations below this limit are characteristic for chronic folate deficiency. To confirm this statement further studies will take into account the urine concentration of formiminoglutamic acid.

Adult↗