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Biomedical subjects

R Huch

Publications and source records attributed to R Huch.

At least 91 records · Page 5Linked to original sources
PubMed1994

Guidelines for blood sampling and measurement of pH and blood gas values in obstetrics. Based upon a workshop held in Zurich, Switzerland, March 19, 1993 by an Ad Hoc Committee.

Guidelines for the clinical indications for measuring pH and blood gas values in fetal blood, the procedures of blood sampling and measurement and some reference values for the evaluation of the data are given. They cover: prenatal sampling of blood from the umbilical vessels in conjunction with cordocentesis, intra partum sampling of fetal capillary blood by skin puncture of the presenting part, post partum sampling of blood from a clamped section of the umbilical cord and general analytical techniques.

Blood Gas Analysis↗
PubMed1994

[Comparative study of the lower uterine segment after Cesarean section using ultrasound and magnetic resonance tomography].

To determine whether ultrasound (US) or magnetic resonance imaging (MRI) gave more accurate and objective information about the thickness and continuity of scarred isthmical myometrium following previous Caesarean section (CS), US and MRI assessments of the scarred myometrium in 10 pregnant women (37-41 weeks gestation) after 1-8 CS were compared with each other and with findings at subsequent elective CS. Vaginal ultrasound gave more accurate information about the condition of the scarred isthmical myometrium than MRI, since US always allowed precise differentiation of isthmical myometrium from the urinary bladder wall and thus measurements of the scar thickness; there was a good correlation to intraoperative observations. MRI achieved better contrast resolution with T2- than T1-weighted and proton density-weighted spin-echo sequences. However, differentiation of the various tissues was either impossible (T1- and protondensity-weighted sequences) or less informative than with US. Image quality of body and posterior wall of the uterus was better with MRI (T2-weighted sequence) than with US.

Adult↗
PubMed1994

Changes in sleep and sleep electroencephalogram during pregnancy.

The impairment of sleep quality is a common complaint during pregnancy. To investigate the changes in sleep in the course of pregnancy, the sleep electroencephalogram (EEG) was recorded and analyzed in nine healthy women on 2 consecutive nights during each trimester of pregnancy. Waking after sleep onset increased from the second (TR2) to the third (TR3) trimester, whereas rapid eye movement (REM) sleep decreased from the first trimester (TR1) to TR2. Spectral analysis of the EEG in nonrapid eye movement (NREM) sleep revealed a progressive reduction of power density in the course of pregnancy. In comparison to TR1, the values in TR2 were significantly lower in the 10.25-11.0-Hz and 14.25-17.0-Hz bands. In TR3, the significant reduction extended over the ranges of 1.25-12.0 Hz and 13.25-16.0 Hz. The largest decrease (30%) occurred in the 14.25-15.0-Hz band. In REM sleep, the spindle frequency range was not affected, and a minor reduction of power density in some frequency bins below 12 Hz was present only in TR3. The study documents major alterations of the sleep EEG that are not evident from the sleep scores and that may be associated with the characteristic hormonal changes occurring during pregnancy.

Adult↗
PubMed1994

rh-erythropoietin stimulates immature reticulocyte release in man.

The pharmacodynamics of single intravenous dosing with recombinant human erthropoietin (rhEPO) was investigated in eight healthy volunteers (150 U/kg, n = 2; 300 U/kg, n = 6) with respect to reticulocyte subdivisions (by fluorescence flow cytometry) and serum ferritin over 6.5 d. The present study shows that bolus rhEPO injection produces an immediate release of high and middle fluorescence (immature) reticulocytes with a high RNA content from the marrow into the circulation, whereas the low fluorescence (more mature) reticulocytes were at first not affected. Serum ferritin decreased markedly within 24 h, reaching a nadir 50% of baseline after 120 h (5 d), with no increase in haemoglobin. Our data suggests that rhEPO triggers premature expulsion of immature reticulocytes from the bone marrow into the circulation independent of its effect in stimulating erythropoiesis and that rhEPO has an effect on serum ferritin concentration which in this dynamic situation is dependent not only on the iron stores.

Bone Marrow↗
PubMed1994

Control of skin blood flow in pre- and full-term infants.

The response of skin blood flow to local ischemia, heating and cooling was investigated at different intervals after birth in 10 healthy full-term babies and 10 preterm postincubator infants using 2 noninvasive and locally neutral methods of microcirculatory measurement: laser Doppler flowmetry and cutaneous oxygen partial pressure (cPO2) estimation with a probe temperature of 37 degrees C. Both groups of infants were capable of myogenic and neural control of skin blood flow. Higher cPO2 values under basal conditions and during reactive hyperemia suggest a raised nutritive capillary blood flow in the preterm group. The increase in cutaneous blood flow during local warming and reactive hyperemia shows that even in neonates on the first day of life no maximal skin vasodilatation is present. An increase in the periodic flow waves attributed to arteriolar vasomotion in 19- to 22-day-old infants, compared to the preterm group and younger babies, indicates that myogenic activity in skin arterioles increases with advancing age.

Blood Flow Velocity↗
PubMed1994

Blood flow velocities in human intraplacental arteries.

OBJECTIVE: To characterise the physiological findings of blood circulation in intraplacental arteries in normal and complicated pregnancies. DESIGN: A descriptive cross-sectional study. Umbilical and intraplacental artery resistance index (RI) Doppler recordings during the last trimester of pregnancy. SUBJECTS: Forty-nine normal pregnancies and ten pregnancies complicated by fetal growth retardation. RESULTS: RI values decreased from the proximal umbilical artery to the distal umbilical artery and to intraplacental arteries. All of these vessels had decreasing RI values towards the end of pregnancy. In pathological pregnancies an abnormal flow pattern in umbilical arteries could be associated with either an abnormal or normal flow pattern in the intraplacental arteries. CONCLUSIONS: Blood flow in intraplacental arteries can be recorded by sensitive color Doppler in normal pregnancies, but in complicated pregnancies variation of the Doppler findings, together with imaging difficulties of intraplacental arteries, seem to impair the applicability of this examination as a diagnostic tool.

Adult↗
PubMed1994

Erythropoietin in obstetrics.

The physiology of maternal and fetal erythropoiesis in pregnancy shows that hematopoiesis, and the stimulation of hematopoiesis, take place separately in the two circulations. Erythropoietin appears the main regulator in both mother and fetus. The human placenta forms a manifest barrier to endogenous and recombinant erythropoietin, thus fulfilling the cardinal precondition for the use of recombinant erythropoietin in the treatment of maternal pregnancy anemia. The prevalence of maternal anemia in pregnancy and post partum is high; up to 95% of cases are due to iron deficiency, compounded post partum by blood loss during and after delivery. Use of rHuEPO for reversing pregnancy and postpartum anemia has given promising initial results.

Anemia↗
PubMed1994

rHuEPO in the treatment of postpartum anemia: subcutaneous versus intravenous administration.

The aim of this study was to determine whether single-shot therapy with recombinant human erythropoietin (rHuEPO) is as effective as divided dosing in postpartum anemia for both subcutaneous and intravenous administration. In a randomized prospective study we treated 95 women with postpartum anemia (Hb < 10 g/dl) within 72 h after delivery with rHuEPO (total dose 300 U/kg body weight) and oral iron supplementation in four treatment groups: group A rHuEPO 150 U/kg s.c. once daily for two consecutive days; group B rHuEPO 150 U/kg i.v. once daily for two consecutive days; group C rHuEPO 300 U/kg s.c. once only; group D rHuEPO 300 U/kg i.v. once only. No significant intergroup differences were found in the mean increase of hemoglobin (P = 0.93 for a difference of 1 g/dl). The mean increase in the single-shot groups was 3 g/dl in 14 days. There was a significant reduction of iron stores in all groups. We conclude that single-shot rHuEPO 300 U/kg body weight corrects anemia just as effectively as divided doses on both intravenous and subcutaneous administration. The overall increase in Hb is only slight but preliminary results indicate that the effect can be enhanced by administrating iron intravenously and by an interval therapy with high-dose rHuEPO.

Adult↗
PubMed1994

Maternal and cord serum vitamin E levels in normal and abnormal pregnancy.

The purpose of this study was to ascertain whether there is an association between reduced vitamin E levels and an abnormal pregnancy. Levels were measured by HPLC in maternal and, where possible, in paired umbilical cord serum from normal and abnormal pregnancies at delivery and in serial serum samples from healthy women during gestation. Abnormal pregnancies were compared with normals. In normal pregnancies, mean vitamin E levels rose from 12.9 +/- 1.1 micrograms/ml in early pregnancy to 22.5 +/- 1.5 micrograms/ml at term (p < 0.05, n = 11). In pregnancies with fetal complications or maternal risks, levels were lower than in normals at corresponding gestational age (p < 0.005 in smokers, n = 20 at > or = 30 weeks & p < 0.01 in hypertensives, n = 4 at 16-23 weeks). Mean maternal and paired cord serum levels in normal pregnancies at delivery > or = 37 weeks were 21.3 +/- 0.6 and 3.8 +/- 0.1 micrograms/ml respectively (p < 0.001, n = 56). Maternal levels in women with a low birthweight infant and in smokers (> 10 cig/day) were significantly lower (p < 0.05, n = 13 & p < 0.0005, n = 12); levels in women with a malformed infant (n = 6) were also reduced, but just barely below the level of significance (p = 0.06). Cord serum levels in complicated pregnancies, however, were unchanged. The results show lower maternal levels of vitamin E in abnormal pregnancies, suggesting a changed vitamin E metabolism.

Biomarkers↗
PubMed1993

An orthostatic uterovascular syndrome--a prospective, longitudinal study.

OBJECTIVE: The interaction between maternal hemodynamics and uterine activity in the upright position was investigated longitudinally (358 measurements) in 40 healthy pregnant women from 20 gestational weeks to term. STUDY DESIGN: Maternal-fetal hemodynamic parameters and uterine contractions were measured noninvasively in four different postures. RESULTS: Hemodynamic disturbances caused by compression of pelvic vessels by the gravid uterus in the upright position were detected in two of 40 (5%) women as early as 24 weeks' gestation; a peak was reached at 38 weeks (71%). With a decrease in the stroke volume (22%, p < 0.001) neither the cardiac output (-11%, p < 0.05) nor the systolic blood pressure (-1.4%, p < 0.05) remained constant, although there was a compensatory heart rate increase. CONCLUSION: A significantly increased number of spontaneous uterine contractions in the upright position is associated with release of the blocked venous return flow and restoration of normal maternal hemodynamics.

Adult↗
PubMed1993

Lack of associations between fetal and maternal serum-erythropoietin at birth.

Erythropoietin (EPO) is known to be the main regulator of erythropoiesis. We wanted to determine whether EPO production during pregnancy takes place independently in the mother and the fetus, and to identify the factors which set the EPO level. Endogenous EPO levels were determined in simultaneous samples from the umbilical vein, the umbilical artery and a maternal vein in 126 mother-child pairs and simultaneously from amniotic fluid (n = 14) in unselected births. Results were related to clinical and biochemical parameters of fetal well-being, mode of delivery, duration of labor, and infant parameters at birth. There was a weak correlation between maternal and fetal log EPO values (umbilical vein: r2 = 0.11; umbilical artery: r2 = 0.08), but a highly significant correlation between log EPO levels in the two umbilical vessels (r2 = 0.91) and between both umbilical blood and amniotic fluid (r2 = 0.41). Maternal EPO levels were lower than fetal levels in 76 cases, higher in 47, and nearly identical in 3. Increased fetal EPO levels were associated with clinical and biochemical indicators of fetal stress. These associations help to explain why EPO concentrations in fetal blood are independent of maternal levels and also indicate that EPO does not cross the placental barrier. These findings are discussed in the light of the animal experimental and in vitro evidence for placental transfer of EPO. Our data, and the work of others, make such a transfer in humans quite unlikely. This observation has therapeutical consequences for the treatment of maternal anemia with recombinant human EPO.

Amniotic Fluid↗
PubMed1993

[Apple-Macintosh compatible software for documentation, management and evaluation of ultrasound findings in obstetrics].

The advantage of using a computer to automate routine calculations and print out charts of the obstetrical ultrasound examination is obvious. This report describes a software designed to simplify the documentation and analysis of ultrasound data in obstetrics. The system is easy to use, even for persons with little computer knowledge. The programme was written in FoxBase+/Mac (Fox Software, Inc., USA). FoxBase+/Mac takes full advantage of the easy-to-learn, easy-to-use Macintosh interface and is also very fast. Another advantage of this software is that it can be used in teaching. Non-experienced examinators can double-check the correctness of their scanning planes by observing the ultrasound pictures with the markers indicating the right measurement sites and the lists of standard values of biometrical parameters for the corresponding gestational age on the screen. In routine obstetrical ultrasound examinations it takes less than 5 min to enter the foetal biometry data and print out reports. These reports are informative and easy to interpret.

Female↗
PubMed1993

[Correlation between reduced amniotic fluid volume and Doppler spectra of fetal blood vessels at term].

The aim of this study was to determine, whether foetuses with reduced amniotic fluid in other-wise uncomplicated pregnancies at term show signs of redistribution of blood flow analogous to foetuses with intrauterine growth retardation. In 33 pregnancies > or = 37 gestational weeks with the largest pocket of amniotic fluid < 2 cm, flow velocity waveforms were recorded for the umbilical artery, middle cerebral artery and renal artery and compared with those of foetuses of the same gestational age and normal amniotic fluid volume. No difference was found in the resistance index (umbilical artery and middle cerebral artery), the pulsatility index (renal artery), or for the cerebral-placental ratio between these two collectives. We conclude, that Doppler examination of foetal vessels does not help to clarify the phenomenon of decreasing amniotic fluid volume during the final period of gestation. We suggest, that the decrease is not caused by renovascular changes, but has intra- or extrarenal causes.

Amniotic Fluid↗
PubMed1993

Lymphocyte beta 2-adrenoceptors and adenosine 3':5'-cyclic monophosphate during and after normal pregnancy.

1. The beta 2-sympathomimetics, used to inhibit preterm labour, bind predominantly to beta 2-adrenoceptors, activating adenylate cyclase to form adenosine 3':5'-cyclic monophosphate (cyclic AMP), a messenger substance which inhibits the enzyme cascade triggering smooth muscle contraction. beta 2-Adrenoceptor density and cyclic AMP formation can be used as markers of beta 2-adrenergic effect. 2. The present study addresses the influence of pregnancy on the beta-adrenoceptor system. beta 2-Adrenoceptor density and cyclic AMP concentrations (basal and evoked by isoprenaline) in circulating lymphocytes were determined at three points in gestation (16, 29 and 37 weeks) and 9 weeks post partum in 22 normal pregnancies. (-)-[125Iodo]-cyanopindolol was used as the ligand to identify a homogeneous population of beta 2-adrenoceptors on lymphocytes. B- and T-cell fractions were estimated from the same samples. 3. beta 2-Adrenoceptor density decreased significantly during gestation until week 37 (P < 0.01), then increased post partum (P < 0.005). Cyclic AMP concentrations (basal and evoked by isoprenaline) were significantly lower after 16 weeks of gestation than post partum (P < 0.05). 4. The results, which cannot be explained in terms of a shift in the lymphocyte (B- and T-cell) ratio, indicate that beta-adrenoceptor density and function are reduced in normal pregnancy and only return to normal post partum. These findings may be of significance in devising future tocolytic therapy with beta 2-adrenoceptor agonists.

Cyclic AMP↗
PubMed1993

Ceftriaxone (single dose) versus cefoxitin (multiple doses): success and failure of antibiotic prophylaxis in 1052 cesarean sections.

The efficacy of perioperative antibiotic prophylaxis in cesarean section with a single dose of ceftriaxone, a long-acting cephalosporin not widely used for prophylaxis, was tested. Ceftriaxone as a single dose of 1 g i.v. versus three doses of cefoxitin 1 g i.v. respectively were used in a prospective, randomized, controlled study consisting of 1052 patients undergoing cesarean section. Postoperative infection rate as measured by fever, endometritis and wound infection was 6.5% with ceftriaxone and 6.4% with cefoxitin. Urinary tract infections were significantly more frequent in the cefoxitin than in the ceftriaxone group (17.8% vs. 9.7%, p < 0.001). Enterococci and Escherichia coli accounted for urinary tract infections 1.86-, respectively, 4.3-fold more frequently with cefoxitin than with ceftriaxone. The time of hospitalization in patients with urinary tract infections was significantly lower with ceftriaxone than with cefoxitin (11 vs. 12 days, p < 0.05). The tolerance in both groups was equally satisfactory. A single dose of ceftriaxone, which is simple, reliable (compliance), well tolerated, inexpensive (fewer urinary tract infections and therefore fewer treatment costs than with cefoxitin) and safe (no overgrowth of pathogens) in our opinion is the antibiotic regimen of choice for prophylaxis in cesarean section in the described circumstances.

Adult↗
PubMed1993

Maternal and fetal erythropoietin: physiological aspects and clinical significance.

Erythropoietin (EPO) is of special interest in the perinatal period in the mother and fetus. On the one hand, thanks to the recent development of highly sensitive radio-immunoassays and the ability to monitor endogenous EPO production, we can now study the physiological aspects of maternal and fetal erythropoiesis and materno-fetal interrelations, and diagnose raised EPO levels as markers of oxygen deficiency. On the other hand, the availability of recombinant human EPO (rHuEPO) permits therapeutic intervention against anaemia during and after pregnancy. This paper reviews available studies showing a rise in maternal and fetal EPO levels in parallel with gestational age and, in certain pathological states of pregnancy, grossly raised EPO levels in amniotic fluid and fetal blood entirely unrelated to maternal values. The theoretical and experimental arguments against transplacental passage of EPO in the human are discussed. Initial results with rHuEPO have shown rapid correction of maternal post-partum anaemia. No studies on its use during pregnancy are available to date.

Amniotic Fluid↗
PubMed1993

Magnesium sulphate increases lymphocyte adenosine 3':5'-cyclic monophosphate in humans.

We determined the effect of i.v. magnesium sulphate, which is often combined with beta 2-adrenoceptor agonists for tocolytic therapy, on lymphocyte cyclic AMP production, extracellular magnesium and blood calcium concentrations. Sixteen healthy volunteers received i.v. magnesium sulphate 1 g h-1 over 8 h; seven volunteers also had infusion of NaCl 18 mg h-1 as control. Venous blood was taken pre- and post-infusion to determine basal lymphocyte cyclic AMP and the increase evoked by 0.1 mM isoprenaline, as well as serum and plasma concentrations of total and non-protein-bound magnesium and calcium. Following magnesium sulphate there was a significant rise in the isoprenaline-evoked increase in cyclic AMP (P < 0.05) and in the magnesium concentrations (P < 0.01) and a decrease in the free calcium concentration (P < 0.01).

Adult↗