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Biomedical subjects

M Meyenburg

Publications and source records attributed to M Meyenburg.

At least 19 recordsLinked to original sources
PubMed1992

Postterm pregnancy: computer analysis of the antepartum fetal heart rate patterns.

The purpose of this study was to establish reference ranges for numerical fetal heart rate (FHR) data in postterm pregnancy and to compare them with the patterns of fetuses under undisturbed condition at term. FHR was analysed on-line by Sonicaid Computer System 8000. A statistically significant decrease in the number of accelerations and decrease of variation in postterm pregnancy was observed. The duration of high variation (high episodes) in the 42nd week of gestation was statistically lower than in the pregnancy at term. These observations should be taken into account by clinicians in the interpretation of FHR records in postterm pregnancy.

Cardiotocography↗
PubMed1992

Small for gestational age twins: a retrospective analysis of clinical and acid-base status immediately after delivery.

In a retrospective study on 86 twins born between 1971 and 1990, the clinical and acidity status of small for gestational age twins in cases of uncomplicated labor was analysed and compared with the status of appropriate for gestational age twins. No difference was observed in Apgar score and umbilical blood pH between growth retarded and normal twins. The single fact of growth retardation without other factors of risk during labor has no influence on clinical status of small for gestational age twins.

Acid-Base Equilibrium↗
PubMed1992

Effect of the vibratory acoustic stimulation on fetal heart rate patterns of premature fetuses.

The purpose of this study was to examine the heart rate patterns before and after a standardized external vibratory acoustic stimulation in a group of 24 healthy premature fetuses at 32-35 weeks gestational age. FHR was analysed on line by Sonicaid Computer System 8000. A significant increase in the number of accelerations and an increase of variation after stimulus were observed. All other FHR patterns such as baseline, high and low episodes did not change significantly.

Acoustic Stimulation↗
PubMed1992

Time interval in twin delivery--the second twin need not always be born shortly after the first.

In order to evaluate the influence of the time interval on the second twin in twin deliveries, we have used more precise criteria than have been used in the literature to date. The following parameters of the twins were analyzed: normal CTG of the second twin recorded continuously during labor and pH value of the umbilical artery blood after delivery as well as clinical state according to the modified Apgar score. We could not find a general influence of the time interval on pH and clinical status of the second twin. Our results indicate that in cases of uncomplicated twin delivery with a normal cardiotocogram there is no necessity for the second twin to be born as soon as possible after the birth of the first twin.

Acid-Base Equilibrium↗
PubMed1991

Effect of continuous lumbar epidural anaesthesia during labour on fetal transcutaneous carbon dioxide.

The effect of epidural anaesthesia during labour on fetal transcutaneous carbon dioxide (tcPCO2) was observed on 27 fetuses. Our results show that in the course of epidural anaesthesia there is an increase in fetal tcPCO2. We can see a slight increase even before administering the test dose, while preparatory measures are undertaken for the epidural anaesthesia. After administering the test dose and after giving the main dose there is a further increase in fetal tcPCO2, which continues for up to 30 min after the main dose has been given. The results suggest that it is important to consider any pathological conditions in the fetus, so as to avoid the possibility of additionally endangering the fetus during epidural anaesthesia.

Adult↗
PubMed1991

Computer analysis of the antepartum fetal heart rate patterns in the intrauterine growth-retarded human fetus using Sonicaid System 8000.

A total of 28 pregnant women with growth-retarded fetuses were studied to examine the antepartum fetal heart rate patterns between 30 and 39 weeks of gestation. Sonicaid Computer System 8000 was used to analyze on line 200 cardiotocograms. We found that there is an increase in the number of accelerations, an increase in variation assessed in beats per minute and in milliseconds, an increase in duration of high episode and a decrease in the number of decelerations.

Acceleration↗
PubMed1991

The effect of maternal oxygen administration on fetal and maternal blood flow values using Doppler ultrasonography.

Thirty-one pregnant women divided into three groups (AGA prepartum, SGA prepartum without distress, AGA in labor) were examined using Doppler ultrasonography before, during and after oxygen administration to mothers via a face mask. The aim of the study was to find out if there was any effect on the blood flow values in the fetal aorta, the umbilical artery, the fetal common carotid artery and the uterine arcuate arteries. The resistance index (RI) did not change in those vessels during maternal hyperoxygenation with one exception: in the group of SGA fetuses the RI in the fetal aorta increased significantly. Blood flow velocity and volume blood flow remained unchanged in the fetal aorta during oxygen administration.

Aorta↗
PubMed1990

[Differences in sonographic measurements of the fetal head and chest].

Differences in measurements using cephalometry and thoracometry ante partum are reported. Two examiners performed fetal head and thorax measurements shortly after one another using the same ultrasonic equipment without knowing the measurements achieved by each other. A series of 195 measurements were made by a few less experienced examiners. The values measured showed a considerable scatter. The average difference between the biparietal head measurements was 2.23 mm, and the standard deviation of the differences of the values measured was 1.94 mm. In a further group of 175 fetuses the measurements were performed by two skilled examiners. For the diameter of the head there was an average measured difference of 1.38 mm and a standard deviation of the differences of 1.11 mm. For the average thorax diameter--corresponding to the arithmetical average from the straight and transverse diameter--the following results were achieved. 4.14 mm average difference of value measured an 3.41 mm standard deviation in the measuring run performed by less experienced ultrasonic examiners as opposed to 2.57 mm average difference and 1.74 mm standard deviation in the group of practised examiners. The average thorax diameter showed a considerably smaller scatter than the transverse thorax measurement on its own. The differences in the values measured could not be seen to be dependent on the gestational age.

Cephalometry↗
PubMed1990

Does pulsed-Doppler ultrasound have mutagenic effects? Application of the Ames mutagenicity assay to test pulsed-Doppler equipment.

Measurement of fetal blood flow has been accepted using pulsed-Doppler ultrasound. Until recently, there has been a lack of investigations concerning the potential risks of this method. The possible mutagenic effect of a pulsed-Doppler system was examined in vitro by applying the Ames test. Tester strains of Salmonella typhimurium indicating point mutations were irradiated (TA 98, TA 100, TA 102, TA 1535, TA 1537, TA 1538). A commercially available duplex system was applied in the experiments emitting an ultrasound beam with a spatial-peak temporal-average of 5.2 mW/cm2 and a spatial-peak temporal-peak of 117 mW/cm2 at a frequency of 2 MHz. The tester strains were sonicated up to 60 minutes, the bacterial suspension being in direct contact with the transducer surface. The ultrasound-exposed bacterial suspensions were compared with nonexposed samples. Reference mutagens were used for checking the sensitivity of the system. The results do not indicate any mutagenic effects.

DNA Damage↗
PubMed1990

The influence of oxygen administration to the mother during labor on the fetal transcutaneously measured carbon-dioxide partial pressure.

The aim of this study was to plot the course of the transcutaneously measured PCO2 (tcPCO2) in the fetus during oxygenation of the mother. In our examination 35 parturients with a suspicious or pathologic CTG were given pure oxygen for 10 minutes at a flow speed of 10 l/min. The fetal tcPCO2 was measured with a TCM 3 measuring device from Radiometer. The measuring temperature was 41 degrees C. The fetal tcPCO2 was 67.2 +/- 3.9 mmHg before the O2 application, during the O2 application it was 67.3 +/- 14.1 mmHg and for the period after the O2 application we found an average measurement of 66.7 +/- 13.9 mmHg. Further we investigated whether, depending on the original levels of the fetal tcPCO2 an O2 application to the mother had a measurable effect on the fetal tcPCO2 levels. The average levels of the tcPCO2 in the fetuses with pathological original levels of greater than or equal to 60 mmHg or with normal levels of less than 60 mmHg did not show any significant differences before, during or after the O2 application. Our own results and reports given in the literature about an increase in the fetal O2 partial pressure during maternal oxygenation lead to the conclusion that in cases with fetal hypoxia, the O2 application to the mother--in addition to other measures for intrauterine reanimation or speedy termination of labor--could be of advantage.

Blood Gas Monitoring, Transcutaneous↗
PubMed1989

Myoglobin in third trimester amniotic fluid of human pregnancy--a potential indicator of fetal hypoxia.

195 amniotic fluid samples from the third trimester were examined for their content of myoglobin by means of radio-immunoassay. 151 of the samples were obtained intrapartum, the rest (44) was taken antepartum by transabdominal amniocentesis within one week prior to delivery. Depending on the myoglobin levels measured, different amniotic fluid groups were defined: (A) amniotic fluids containing no myoglobin or traces of it (less than 3 ng/ml), (B) amniotic fluids with moderately elevated myoglobin levels (3-10 ng/ml), (C) amniotic fluids with high myoglobin levels (greater than 10 ng/ml). Myoglobin levels above 3 ng/ml could be measured in 98 of the 151 samples taken intrapartum. In the amniotic fluids drawn antepartum the proportion of "myoglobin-positive" samples (greater than 3 ng/ml) amounted to only 22.7% (10 out of 44 samples). In pregnancies with amniotic fluids showing high myoglobin levels intrapartum, the prevalence of meconium staining of the samples, pathological cardiotocograms intrapartum and metabolic acidoses in umbilical artery blood samples was significantly higher than in pregnancies with myoglobin-negative amniotic fluids. The frequency of cesarean sections for fetal distress rose with increasing myoglobin levels in amniotic fluid, being 5.7, 13, and 18.2% in Group A, B and C respectively. In the pregnancies in which the amniotic fluid samples were taken antepartum, the prevalence of meconium-stained amniotic fluid increased with elevating amniotic fluid myoglobin (p less than 0.05, Group A vs. Group C). The frequency of cesarean sections for fetal distress and of neonatal depression immediately after delivery was considerably heightened in the cases with myoglobin-positive amniotic fluids antepartum compared to those with myoglobin-negative liquor.(ABSTRACT TRUNCATED AT 250 WORDS)

Amniocentesis↗
PubMed1988

[Use of a stapling device in abdominal cesarean section].

This is a report on the use of a stapling device for caesarean sections. The device can be inserted right and left after a very small median uterotomy. It cuts the uterine wall and at the same time places clips on the edges of the wound. The clips are made of a hydrolysable material that can be absorbed in the tissue and can also be used for surgical stitching. Haemostasis is definitely assured. No adverse reactions or disadvantages for the patients have been noticed to date.

Cesarean Section↗
PubMed1984

[A simple immersion test object for the evaluation of axial and lateral resolution of ultrasound pulse echo instruments].

We introduce a test object usable in a water tank for the determination of the axial and lateral resolution of ultrasonic pulse echo equipments. Measuring wires with a diameter of 0.2 mm form the bounds of a measuring line. The distance between the wires is infinitely variable during the test. This will make the smallest distance which can be resolved in the sonogram more accurately determinable than with the usual test objects with rigidly arranged rods.

Humans↗
PubMed1983

[Densitometry and fetal superficial cell count in the amniotic fluid for the determination of fetal lung maturity].

It was shown that a spectrophotometric investigation of the amniotic fluid for the determination of fetal lung maturity can be achieved with a photometer of the wave length 644 nm (CD) and 623 nm (HG) in conjunction with a count of superficial cells. In a small number of investigations the combination of spectrophotometry and fetal cell count is a sufficiently accurate method to determine fetal lung maturity.

Amniotic Fluid↗
PubMed1983

Investigation into the possible genetic effects of diagnostic ultrasound.

The mutagenic effect of DUS (diagnostic ultrasound) was examined using two generators emitting continuous waves and pulsed waves, respectively. Three different test systems for mutagenic activity were employed in this study. 1. The frequency of sister chromatid exchanges (SCEs) was determined in metaphase chromosomes of human lymphocytes and of Chinese hamster ovary (CHO) cells sonicated at different stages of the cell cycle. 2. The induction of DNA single strand breaks was tested in CHO cells treated with continuous wave ultrasound. Following sonication an endonuclease was introduced into the cells converting single strand breaks to chromosomal aberrations scorable in the following metaphase. 3. The influence of DUS on the number of point mutations was evaluated in the Ames test. A tester strain of Salmonella typhimurium indicating base substitutions was sonicated. At the present stage, all results proved to be completely negative and could thus not support the view of any mutagenic activity of diagnostic ultrasound.

Animals↗
PubMed1982

[Procedures in the pregnant and non-pregnant uterus under sonographic control (author's transl)].

Several procedures during pregnancy under ultra-sonographic control are described. Amniocentesis and puncture of the fetus may be done accurately without too much problems when a multi-element ultra-sound scanner is used for sonographic control. The principle of manipulation with ultra-sonographic control may be used for curettage. Instruments within the uterus may be localized and their movements can be submitted to continual visual control. A curettage under sonographic control may reduce the risk of the curettage in cases of uterine anomalies, anomalies of the position or unusually soft uteri.

Amniocentesis↗