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Biomedical subjects

G Kynast

Publications and source records attributed to G Kynast.

At least 19 recordsLinked to original sources
PubMed1989

Simplified quantitative determination of phospholipids in amniotic fluid, alveolar lavages and milk using high performance liquid chromatography (HPLC).

A one step HPLC method for the determination of the main phospholipids, phosphatidylglycerol (PG), phosphatidylinositol (PI), phosphatidylethanolamine (PE), phosphatidylcholine (PC), sphingomyelin (SP) and lysolecithin (LL) in amniotic fluid, milk, tracheal secretion, lung lavages, gastric aspirates, infant formulas and some other human and animal media has been developed. Quantitation occurs automatically using computer calculation and lysolecithin as an internal standard. Detection limits are at about 0.2 micrograms/100 ml but may rise to about 0.3 micrograms/100 ml in cases of high fat levels or other interfering compounds. Recovery rates measured in amniotic fluid fluctuate around the 100% level. Time required for a single analysing including a blank run and a calibration standard solution measurement amounts to about two hours. In series analysis 12 samples per day can be examined, while the required time per sample is reduced to 40 minutes. As phospholipids carry an important function in many spheres of medicine, the improvement in specific quantitative determination of these compounds is of great importance.

Amniotic Fluid↗
PubMed1988

Determination of the phospholipid content of human milk, cow's milk and various infant formulas.

The phospholipid (PL) content of human milk, cow's milk, and various infant formulas was determined by recently developed high performance liquid chromatography (6). As the examinations promised, the content of phosphatidylinositol (PI), phosphatidylethanolamine (PE), phosphatidylcholine (PC), and sphingomyelin (SP) was not changed by homogenization and pasteurization of cow's milk. Levels of phosphatidylglycerol (PG) were below the detection limit. Furthermore it has been proved that human milk and cow's milk are more or less identical in PL content. Some of the PL in human milk varies during the course of pregnancy and postpartum. PI, PC, and SP content in the prepartum mammarial secretion lies above the average content of mature human milk after delivery. Before the contractions start, all the PL examined show a more or less considerable decrease. PC drops to 30% of the value at the beginning of the examination six weeks before delivery. PG contents are very low throughout the whole period. Contrary to the others, PC content recovers three weeks after delivery, which may be the result of the endogenous surfactant replacement system. To compare PL content with human milk and cow's milk, 13 different infant formulas have been examined. There are considerable differences to be found in and among adapted milk, partially adapted milk, and special formulas. None of the PL examined could be found in all the infant formulas, where PG content was usually low, except in some Milupa formulas. PE and PI were not to be found in some special formulas. Most of the formulas contain high amounts of SP, in some cases higher than the amount of PC. To a certain extent infant formulas contain a considerably greater amount of other PL concentrations than human milk and cow's milk. In most of the formulas examined the PL content is generally so high, that it can be used as a source of PL for the newborn.

Animals↗
PubMed1988

Effect of blood and meconium on the determination of phospholipids in amniotic fluid using high pressure liquid chromatography.

This paper presents the evaluation of the effects of blood and meconium on the determination of the phospholipids phosphatidylglycerol (PG), phosphatidylinositol (PI), phosphatidylethanolamine (PE), phosphatidylcholine (PC), sphingomyelin (SP) and lysolecithin (LL) in amniotic fluid. Phospholipids were analyzed by a new method using high pressure liquid chromatography (HPLC), which is based on the procedure of BRIAND et al. The method was extended for quantitative determination with lysolecithin as internal standard. The HPLC equipment consisted of two pumps, an HPLC programmer, an HPLC oven, a UV detector and an integrator. The chromatographic separation was achieved on a 25 cm DIOL-column and a 6 cm guard column packed with silica SI 60. The oven temperature was 55 degrees C and the detector wave length was 201 nm. The chromatographic mobile phase was composed of two solvents, acetonitrile and water. A solvent gradient was run from 2.4% water to 15% water between 5 and 13 minutes. Phospholipids were extracted according to the procedure of GLUCK. Before extraction 40 micrograms of LL as internal standard were added to 2.0 ml amniotic fluid. In a standard solution the phospholipids PE, PC, SP and LL were baseline separated, in the case of PG and PI a perpendicular division of the peaks was necessary. To evaluate the effect of contamination by blood and meconium, various amounts of blood and meconium were added to uncontaminated amniotic fluid samples. Contamination by blood caused a rise of the concentrations of PC, PE and SP up to tenfold. PG and PI concentrations were not affected by blood staining.(ABSTRACT TRUNCATED AT 250 WORDS)

Amniocentesis↗
PubMed1988

Effect of long-term treatment with antiepileptic drugs on the vitamin status.

The status of vitamins A, B1, B2, B6, B12, C, D, and E as well as that of beta-carotene, biotin, and folate in the blood of over 500 epileptics was compared with that of a normal population. Male and female epileptics showed a poorer supply of vitamins B2, biotin, folate, and 25-hydroxycholecalciferol; the males, of only vitamin B6, B12, and E, and the women, of only vitamin A. Concentrations of beta-carotene and vitamin E in female epileptics were higher. The evaluation of relations between vitamin concentrations and mean daily dose, total dose of anticonvulsants, and duration of therapy suggested a possible influence of anticonvulsant medication on vitamins B1, B2, B6, C, D, E, beta-carotene, biotin, and folate. Concentrations of B vitamins as well as of folate were distinctly lower in patients under monotherapy with enzyme-inducing drugs than in those under valproate sodium. There was no relationship between bone mineral content and 25-hydroxycholecalciferol levels and between the neurographic parameters and the neurotropic vitamins of the B group, which also had no influence on concentration performance. Patients with poorer results in tests of the function of the central and the peripheral nervous system displayed a tendency towards lower vitamin-C levels. There were indications of potential links between immunological status and vitamin B6 and biotin. Males and females with a poorer supply of vitamin C, as well as males with lower riboflavin levels, showed a tendency towards macrocytic anaemia. Cerebellar disturbances were associated with lower concentrations of folate, of vitamin C or D, and possibly of biotin. The incidence of gingival hyperplasia could be linked to riboflavin, to biotin, and possibly also to vitamin C, D, or folate status.

Adult↗
PubMed1986

Effect of oral zinc application during pregnancy.

The beneficial effects of the oral application of zinc aspartate in pregnancy is investigated in a randomly selected study group of 179 patients and a control group of 345 patients. This study confirms the prophylactic effectiveness of zinc replacement in reducing the overall complication rate for both mother and fetus and in particular for large-for-date and small-for-date infants. The therapy is well tolerated and accepted by the patients and causes no side effects. The results are in line with those of other working groups reporting on zinc as an important element with protective effects on fetal growth and development in pregnancy.

Adult↗
PubMed1984

A method for testing the specificity of influenza A virus-reactive memory cytotoxic T lymphocyte (CTL) clones in limiting dilution cultures.

This paper describes a system for determining the frequency and fine specificity of influenza A virus-immune memory cytotoxic T cell (CTL) clones from limiting dilution (LD) microcultures. We found that such experiments can only be performed (1) by analyzing the clonal response of CTL from wells of replica plates containing fractions of one original plate, (2) when it has been ascertained that splitting is possible at the clonal level, and that each fraction of a microculture well gives an identical response on target cells infected with the stimulating virus. With these requirements fulfilled we found that short term CTL clones from LD microcultures from influenza A virus (A/X-31)-immune mice (C57BL/6) occur at a frequency of f = 1:546 to f = 1:6303. The effector cells carry the Lyt-2.2 marker and are specific for target cells infected with the immunizing virus (influenza virus A/X-31). They do not lyse NDV (Newcastle disease virus) or HSV (herpes simplex virus)-infected or NK (YAC) target cells.

Animals↗
PubMed1983

Determination of zinc in amniotic fluid in normal and high risk pregnancies.

Taking the necessary precautions essential for accurate trace element analysis, the zinc concentrations of 227 samples of amniotic fluid taken at term were determined by means of neutron activation analysis. Half of the zinc was found to be bound to the particles present in amniotic fluid. In the control group (123 cases) the zinc concentrations ranged from 25-261 micrograms/l for untreated samples and from 14-143 micrograms/l when the samples were centrifuged for 10 min at 22 000 g prior to analysis. The values showed log-normal frequency distributions and were lower than any of the values published in the literature to date. No statistically significant difference could be found, when zinc concentrations of various risk groups (mothers suffering from gestosis or diabetes mellitus, newborns hypo- or hypertrophic, twin births) were compared with the zinc concentration of the control group. The amniotic fluid zinc concentration is not, therefore, a suitable indicator for the diagnosis of disturbances of the embryonic development.

Amniotic Fluid↗
PubMed1982

The application of gel filtration, immunonephelometry and electrothermal atomic absorption spectrometry to the study of the distribution of copper-, iron- and zinc-bound constituents in human amniotic fluid.

Gel filtration with Sephacryl S-300 was used to fractionate copper-, iron-, and zinc-bound proteins and low molecular mass constituents in samples of amniotic fluid collected at delivery. The fractions were analysed for copper, iron and zinc by electrothermal (carbon furnace) atomic absorption spectrometry. The proteins associated with these metals were determined by immunonephelometry. The results showed that caeruloplasmin, transferrin and albumin are the major proteins that bind copper, iron and zinc, respectively. Less than 10% of the metals, except iron, recovered from the column was bound to low molecular mass constituents. Comparisons between the distribution of these elements in amniotic fluid and serum are shown and discussed.

Albumins↗
PubMed1982

[Enzymatic lecithin determination in amniotic fluid for antepartal diagnosis of lung maturity - a multi-center study (author's transl)].

A new test-combination for the enzymatic determination of lecithin in amniotic fluid for the assessment of fetal lung maturity has been developed by Boehringer Mannheim. This test was evaluated by 12 hospitals and has been compared with the L/S ratio, the foam-test or the densitometric determination of lecithin. The assay is based on the hydrolysis of lecithin by phospholipase C which starts an enzymatic chain reaction in which NADH consumption if measured photometrically. The intra- and interassay precision were characterized by CV values below 10%. Average recoveries of lecithin were 95-102%. It is recommended to centrifuge the samples (10 min, 700 g) and to start the analysis as soon as possible after receipt of the specimen. The total amount of time required is 2 hours for a single determination. Batches of up to 10 samples require little extra time. An opened test-combination can be used for a maximum of 30 single determinations. Comparison of the quantitative enzymatic lecithin determination with other methods showed that the critical value for lecithin is 5.0 mg/100 ml. Above 5.1 mg/100 ml no case respiratory distress syndrome was observed. The good precision accuracy and the simple handling make the enzymatic lecithin determination suitable for routine use.

Amniotic Fluid↗
PubMed1981

A new test-combination for the enzymatic determination of fetal lung maturity.

Based on the enzymatic method for the determination of lecithins, clinical tested by DIEDRICH and coworkers [1], there is a test-combination available now which is soon to be brought onto the market by the film Boehringer, Mannheim, Germany. Full working instructions are given with the test. The biochemical basis of the method is the decomposition of the lecithins in amniotic fluid--which originate from the fetal lungs--by means of a phospholipase C. In an enzymatic chain reaction the split phosphorylcholine as a parameter of lecithins is determined quantitatively photometrically by consumption of NADH. Measurements are made against a reagents blank and Precilip EL (BOEHRINGER, Mannheim) as a quality control. The test set can be used for some months with a maximum of 30 single determinations. In a double-blind study the enzymatic method was tested against the densitometric determination of lecithins by KYNAST and SALING [2]. The examination of 39 amniotic fluid samples which were won by amniocentesis at about the 30th to 42nd week of gestation showed a highly significant relationship (p less than 0.001) between both methods. Meconium and blood raised the lecithin level so that these contamination can lead to false positive values. As a result the examined test-combination is a usable method for determining fetal lung maturity from uncontaminated amniotic fluid samples. Because of its specificity and small apparative costs, it further is suited as a standard comparison method to those other existing methods and may lead to standardisation of lung maturity diagnosis.

Amniotic Fluid↗
PubMed1980

[Is spectrophotometric analysis of the amniotic fluid a simple method for the determination of fetal pulmonary maturity? (author's transl)].

The samples of amniotic fluid from 55 transabdominal amniocenteses were examined with a simple spectrophotometric test for the predictive value on the risk of respiratory distress syndrome. There was a highly significant correlation between the lecithin content and the optical density of the amniotic fluid at 650 nm (r = 0.065 at p <0.001). No infant with an extinction threshold value of less than 0.15 had neonatal respiratory distress syndrome.

Amniocentesis↗
PubMed1980

Lecithin Content of amniotic fluid in twin pregnancies with and without long-term tocolytic therapy.

During the period from January 1973 to October 1979, 55 transabdominal amniocenteses were performed on 40 twin pregnancies and the lecithin content of the amniotic fluid obtained was established in order to determine the fetal lung maturity. The lecithin determination was performed densitometrically according to Kynast and Saling. Through long-term tocolysis in twins the surfactant production rate is delayed in each phase of the pregnancy, whereas in a collective without long-term tocolysis one can reckon with sufficient fetal lung maturity from the 35th week onwards.

Adrenergic beta-Agonists↗
PubMed1979

[Amniotic fluid concentrations of thyroxine, reverse triiodothyronine and lecithins].

In the present study we tried to find out relationships between lung maturation-assessable by aid of lecithin concentrations in amniotic fluid-and fetal thyreoid gland function. In 256 pregnant women amniocentesis was done after 31/0 weeks of gestation, and concentrations of thyroxin, of reverse triiodothyronine and lecithins were measured. While thyroxin and lecithin concentrations proved not to be correlated, the rT3 and lecithin concentrations showed significant correlation (2 p less than 0.001). The curves measured were interpreted as signs of maturity of various organs (lung, thyreoid gland). We found out, that clinical value of measuring thyreoid gland hormones in relation to diagnosis of fetal maturation is of less importance.

Amniotic Fluid↗