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Biomedical subjects

W Schmidt

Publications and source records attributed to W Schmidt.

1,024 records · Page 57Linked to original sources
PubMedDate not supplied

[Reliability of duplex sonography in non-quantitative determination of blood flow in comparison to inductive flow measurement--an in vitro study].

Using an experimental design permitting generation of a pulsatile "flow-velocity waveform" corresponding to the fetal aortic signal, the influence of measurement depth, the angle between the Doppler beam and the vessel, the high-pass filter and the extent of overlap between the "sample volume" and the vessel cross-section were studied in vitro. The Resistance Index showed the best relation to inductive flow measurement, which was defined as standard. Considering the conditions prevailing during clinical studies, good reliability is likely at angles of between 0 degrees and 60 degrees (120 degrees-180 degrees) over the entire range of measuring depths (4-13 cm) and when using 100-200 Hz high-pass filters. The magnitude and location of the sample volume does not seem to play a decisive role provided a part of it is within the sonographically imaged "vessel" and there is no likelihood of interference from vessels in the immediate vicinity in which blood flow is in the same direction.

Aorta↗
PubMedDate not supplied

[Prenatal diagnosis of thanatophoric dwarfism with cloverleaf skull].

Thanatophoric dwarfism is a rare condition occurring in 1 in 100,000 births. To date, only 2 cases have been reported on in which this condition was diagnosed prenatally before the 24th week of pregnancy post menstruationem. The majority of cases reported so far were born by cesarean section. This condition can be diagnosed early by measurement of the fetal diaphyseal bones and accompanying specific diagnostic measures to establish the possible presence of malformations. The pregnancy can then be terminated if need be, and unnecessary interventions thus avoided.

Abortion, Eugenic↗
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[Fetofetal transfusion syndrome in twin pregnancy with prune belly syndrome].

The authors report on a twin pregnancy with one phenotypically normal twin and one with Prune-Belly-syndrome. Since a severe urethral obstruction-malformation complex was apparent, a premature vaginal delivery was aimed for. A pathologic CTG of the healthy twin, with silent and sinusoidal graph pattern, rendered a primary cesarean section necessary in the 36th + 0 week of pregnancy. The cause was established as a fetofetal transfusion syndrome with severe anemia of the phenotypically normal newborn. Following appropriate blood transfusion the subsequent development of this child was free of complications. The child with Prune-Belly-syndrome died on the second day of life.

Adult↗
PubMedDate not supplied

[Controlled acoustic and photic stimulation of the fetus in the last pregnancy trimester].

The aim of the study communicated here was to check any fetal reactions occurring after external stimulation (light-optic and acoustic stimuli), depending on fetal behavioral status. The group studied (acoustic/light stimulation) comprised 85 patients with normal course of pregnancy at term (37th to 42nd week of gestation). They were compared with a control group of nonstimulated patients (n = 26), also with normal course of pregnancy and corresponding gestational age. Fetal heart frequencies and an external tokogram were recorded synchronously with the fetal respiration, body, limb and eye movements registered simultaneously by two independent observers and the fetal behavioral statuses were defined (Nijhuis, Prechtl et al. 1982; Boos and Schmidt 1984; van Vliet et al. 1985). The stimulation methods used were as follows: 1. Single-frequency pure tone (2 kHz, 120 dB, 5 sec) 2. Sawtooth-modulated pure tone (0.5-2.0 kHz, modulation frequency 10 Hz, 120 dB, 5 sec) 3. Low-frequency, sawtooth-modulated pure tone (with vibration effect), (0.1-0.3 kHz, modulation frequency 10 Hz, 120 dB, 5 sec) 4. Light stimulation: electronic photographic flash, luminous intensity 25 X 10(6) Lux/10(-3) sec, 8 flash sequences in 10 sec, distance from maternal abdomen 20 cm. In order to rule out purely coincidental changes in fetal attitude, both genuine and "sham" stimulations were performed in randomized sequence, in the latter case without any acoustic or light-optic signals. No differences in fetal reactions were found with the three different acoustic stimulation methods.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustic Stimulation↗
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[Breech childbirth--obstetrical and antepartum ultrasonography findings].

The clinical and sonographic findings in 662 cases with birth from breech presentation were compared with the obstetric and sonographic data of a control group (births from vertex presentation). There were significantly more primiparae aged over 30 (16%) in the breech birth group investigated than in the control group (p less than 0.001). Vaginal bleeding and/or premature labor were found more frequently in gravidae with breech presentation than in those with vertex presentation (p less than 0.001). Also, premature births occurred significantly more frequently (22%) in the former group than in the latter (9%; p less than 0.001). Furthermore, the proportion of newborns weighing less than 2500 g was higher in the breech presentation group (20%) than in the vertex presentation group (only 5%; p less than 0.001). In addition, newborns with growth retardation, with a weight percentile less than 5 were significantly more common in breech (6%) than in vertex presentation (2.8%; p less than 0.001). Uterine anomalies (in 5.5%) were more common in breech presentation cases than in the control group (0.0%; p less than 0.001). Oligohydramnios was diagnosed by sonography in 20% of the cases with breech presentation, but only in 6% of births from a vertex presentation (p less than 0.001). A pathologic placental location (placenta previa) was found more frequently (3.5%) in cases with breech presentation than in the control group (1.1%; p less than 0.01). Pathologic fetal movement was sonographically observed in 7% of the cases with breech presentation, though only in 1.6% of cases with vertex presentation (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Effects of intracoronary administration of contrast materials on left ventricular dimensions and rate of relaxation.

The effects of intracoronary administration of ionic and nonionic contrast materials on (LV)left ventricular contractile state, relaxation rate (peak -dp/dt and [-dp/dt]50), and dimensions were determined in eight morphine-chloralose anesthetized dogs. Meglumine sodium diatrizoate caused decreases in peak dp/dt and -dp/dt and increases in left ventricular end systolic dimension (LVESD'), end diastolic dimension (LVEDD'), and end diastolic pressure(LVEDP). The decreases in peak -dp/dt and(-dp/dt)50 persisted after peak dp/dt returned to and exceeded control levels. Calcium meglumine sodium metrizoate caused increases in peak dp/dt but decreases in peak -dp/dt and(-dp/dt)50 and no significant changes in LVEDP, LVESD', or LVED'D. Metrizamide caused no significant changes. Ionic contrast materials induce important changes in LV dimensions and rate of relaxation in addition to producing a depression in contractile state. The decreases in relaxation rate are not reversed by addition of calcium ions.

Animals↗
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[Prenatal diagnosis of severe neural tube defect in negative biochemical findings].

With reference to a case of occipital encephalocele associated with iniencephaly diagnosed by ultrasonography in the 20th week of pregnancy, the diagnostic problems of craniospinal defects, factors influencing prognosis and clinical consequences are described. Even when results of biochemical tests are negative, minute neural canal defects can be diagnosed early by ultrasonography. In the authors' opinion an ultrasonographic diagnosis of encephalocele represents an indication for termination of pregnancy, in view of the poor prognosis.

Abnormalities, Multiple↗
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[Function of the cytotrophoblast in the amniotic fluid/fetus compartment].

In the trophoblast cells of the fetal membranes, PAS-positive substances are demonstrated which are released intermittently into the intercellular space. It is incorrect to designate them as fibrinoid, since degeneratively altered material is not involved. This intracellular substance is with certainty the morphological substrate of the barrier in the region of the feto-maternal contact. It exerts a filter action and probably also acts in the sense of an immune barrier: lymphocytes cannot migrate through it in large numbers. The intercellular substance is flushed out with a flow of fluid through the remaining layers of the fetal membranes into the amniotic fluid. It passes into the fetus by swallowing movements and forms a major proportion of the meconium.

Amniotic Fluid↗
PubMedDate not supplied

[Fetal arrhythmia].

Our present knowledge of fetal arrhythmias is described with reference to the literature and to the authors' personal experience. Most types of arrhythmia are harmless. Fetal tachyarrhythmias are of clinical importance, because of the danger of fetal cardiac insufficiency, and atrioventricular blocks because they are closely associated with infantile heart defects and maternal collagen disease. Problems of diagnosis and management are discussed.

Arrhythmias, Cardiac↗
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[Fetal heart rate and Doppler flow parameters in fetal blood vessels--evaluation of 2,517 individual signals].

Analysis of more than 2500 doppler flow signals in three patients was performed to evaluate the influence of fetal heart rate (fhr) variation on S/D-ratio in fetal vessels. Little differences of S/D-ratio in fetal vessels (descending aorta, umbilical arteries) were detected within the physiological variations of fhr (120-160 bpm) (envelope of regression line -0.007, -0.006). Analysing inter- as well as intraindividual variation only minor effects of fhr alteration can be observed in clinical application of doppler flow velocimetry. Dopplersonographic measurements, however, should be performed for at least a three minute period (for each vessel) to avoid false-positive or false-negative interpretation of short term changes of doppler signals. This is especially important in distressed fetuses.

Adult↗
PubMedDate not supplied

[Doppler ultrasound of fetal blood vessels--optimizing the diagnostic value by a combined diagram].

The dopplersonographic data of 1926 pregnant women in the 3. trimester of pregnancy was used to evaluate a graphic system for the analysis of A/B-ratio in fetal vessels (pulsed wave duplex system; descending aorta and umbilical arteries). The basis of the newly developed combination diagram were dopplersonographic standard values (single cut off and pregnancy duration related percentiles). One of the results was the fact, that the combined measurement and analysis of both fetal vessels increased the positive predictive value compared to single measurements. The value of dopplersonographic examinations in the aorta was slightly better than those in the umbilical arteries. The combined diagram showed a marked improvement in graphicness, especially in follow-up cases, and a partial improvement in statistical values.

Aorta↗
PubMedDate not supplied

[Pregnancy and labor in underweight pregnant patients].

The impact of underweight (Broca-index < 78%) on pregnancy, delivery and puerperium were studied in 104 matched pairs. Match criteria were: age, parity, and height. Underweighed pregnant women were significantly more likely to have an multitude of adverse outcomes, including hypotension (p = 0.0001), anemia (p = 0.02), premature labor (p = 0.0001), premature delivery (p = 0.009), small for gestational age (p = 0.02), hyperbilirubinemia (p = 0.02) and a higher rate of neonatal admission to the intensive care unit (p = 0.03). Underweighed women are at high risk for maternal and perinatal outcome.

Adult↗