[Five-year evaluation of implants in the resorbed maxilla]. / Vijfjaarsoverleving van implantaten in de geresorbeerde bovenkaak.

The survival of implants placed in the resorbed maxillae was investigated. Both edentulous and partially edentulous patients were evaluated including those who underwent 'sinus lift' procedures. The group of patients with a sinus floor augmentation showed a five-year cumulative survival rate varying between 100% for fixed bridges on implants in the partially edentulous maxillae and 75.6% for implants under overdentures placed in severely resorbed edentulous maxillae. It is concluded that placement of implants in the augmented sinus-floor is justified, if the patient is well informed. The procedure can provide a good solution for the prosthetic problems of patients with a resorbed maxilla.

Proliferative cell activity in correlation to human chorionic gonadotrophin release of trophoblast tissue of tubal pregnancy.

The degree to which the relative rise of serum human chorionic gonadotrophin (HCG) concentration was related to proliferative cell activity and the biological vitality of tubal pregnancy was investigated. Salpingectomy was performed in 15 patients diagnosed as having non-ruptured tubal pregnancy. Serum HCG was evaluated twice preoperatively, with a 48-h time interval. Proliferative cell activity was measured through the use of the cell proliferation marker 'Ki-67'. A significant correlation between the relative increase in HCG over a 48-h period, independent of the initial serum HCG value, and the biological cell activity of the trophoblast was shown. Furthermore, it became evident that cell activity was also correlated to the intracellular HCG of the trophoblast. The relative increase in serum HCG over a period of 48 h can serve as a parameter for the biological activity of the trophoblast in tubal pregnancies.

Semicontinuous Detection of 1,2-Dichloroethane in Water Samples Using Xanthobacter autotrophicus GJ 10 Encapsulated in Chitosan Beads.

A semicontinuous microbial assay for the determination of halogenated short-chain hydrocarbons in water samples was developed. The bacterium Xanthobacter autotrophicus GJ 10 forms dehalogenating enzymes, which liberate the halides in 1,2-dichloroethane as halogen ions. Cells of the organism were immobilized in chitosan beads and placed into a tube reactor, whose outlet was connected to a flow-through cell with chloride-selective potentiometric electrodes. Water samples were delivered continuously to the system, and the EMF was recorded. Both the difference in EMF between blank and sample and the velocity of the EMF change were used for calibration. The detection limit for 1,2-dichloroethane was below 0.5 mg/L; the relative standard deviation was <10%. The effects of several parameters like flow rate and cell density were studied in detail.

Localization and distribution of vasoactive neuropeptides in the human placenta.

Neuropeptides play an important role in the regional regulation of blood flow and hormone secretion. Few studies report the presence of peptides in the human placenta. Our experiment evaluates neuropeptides in the human placenta using immunocytochemical techniques. Representative tissue sections from full-term placentae were fixed immediately after delivery and processed into paraffin sections or frozen. They were treated with multiple immunofluorescence, streptavidin-biotin-peroxidase complex and immunogold-silver staining techniques in combination with well-established monoclonal and polyclonal antibodies, using appropriate absorption controls to ensure the validity of the staining. Vasoactive intestinal polypeptide (VIP), calcitonin gene-related peptide (CGRP), neuropeptide tyrosine (NPY), galanin, somatostatin, met-enkephaline, helodermin and substance P-like immunoreactivities were demonstrated within decidual cells. Endothelin-1 was found in both trophoblasts and endothelial cells. Peptide immunoreactivities in the human placenta especially at the decidual interface between mother and fetus supports a role for the diffuse neuroendocrine system (DNES) in the regulation of placental blood flow critical for fetal growth and development.

Proliferative activity in ectopic trophoblastic tissue.

Clinical observations have shown that tubal pregnancies develop individually different biological activities such as different growth rates, levels of beta human chorionic gonadotrophin (beta-HCG), or rates of tubal wall destruction. In the present study, we evaluated the proliferative activity of ectopic cytotrophoblastic tissue using immunocytochemistry with antibodies to Ki-67 (clone MIB-1). The rates of proliferation obtained were related to the maternal serum beta-HCG values. Reference data were obtained from placentas of intact intrauterine pregnancies (group I, n = 14). The proliferative activity of this tissue was compared to that of cytotrophoblastic tissue of tubal pregnancies (group II, n = 27). Ki-67-immunostained as well as non-stained cytotrophoblastic nuclei of the villi and the trophoblastic columns were counted separately, and results were expressed as percentage of positive cells. Serum beta-HCG values were determined twice, 48 h and immediately before operation. The cytotrophoblastic cells of intact intrauterine pregnancies (group I) showed uniform and high proliferative activities (80% on average in villi, 84% on average in columns). The average Ki-67 proliferation rate was significantly lower (P < 0.001) in trophoblastic tissue of tubal pregnancies (group II; 42% on average in villi, 61% on average in columns). Within the group of tubal pregnancies, higher intragroup differences were observed. The number of Ki-67-labelled cells was independent of the absolute preoperative serum beta-HCG values in both groups, yet they were clearly related to the relative increase of beta-HCG in maternal serum. At higher proliferation rates, there was a significant, growing increase of beta-HCG values (P < 0.01). We have found immunohistochemical evidence to support the previous clinical speculations that tubal pregnancies develop more heterogeneously and more slowly than intact intrauterine pregnancies. The development of the beta-HCG concentrations may be taken as an indirect parameter, reflecting proliferative activity of the trophoblast.

Continuous-wave Doppler investigation of uteroplacental vessels in high-risk pregnancies as predictor of fetal growth retardation and pregnancy-induced hypertension.

Continuous-wave Doppler sonography of uteroplacental vessels and the umbilical artery was used as an additive method in the management of risk pregnancies. Its major advantage lies in permitting noninvasive access to placental perfusion. In a sample of 650 singleton pregnancies considered at risk, flow patterns of the right and left uterine and arcuate arteries and of the umbilical artery were obtained. Increased resistance in uteroplacental circulation alone (90th percentile of resistance index and/or notching) was seen in 62 of 100 patients with confirmed growth retardation, proving the key role played by uteroplacental perfusion disorders. Early diastolic notching as well as incomplete vascular flow patterns were also found significantly more often in the growth-retarded group compared to the controls, especially in pregnancies additionally beset by hypertensive disorders. Doppler study of both utero- and fetoplacental circulation increased the sensitivity to 76% in pregnancies with intrauterine growth retardation, and to 90% in those cases with an additional risk of pregnancy-induced hypertension, while the false-positive rate (100-specificity) remained acceptable (17%).

[Diagnostic value of continuous wave (cw) Doppler sonography in maternal diabetes mellitus]. / Der diagnostische Stellenwert der Continuous-wave-(cw) Dopplersonographie bei mütterlichem Diabetes mellitus.

Doppler studies of umbilical, uterine and arcuate artery velocity wave forms were performed in 40 insulin-dependent diabetic women in the first and second half of pregnancy. Using a continuous-wave Doppler device, the resistance index (RI) was calculated to determine the degree of vascular resistance in utero-placental and foeto-placental compartment. The 90th percentile was used to classify flow velocity profiles. In addition, diastolic notching and incomplete registration of uterine and arcuate arteries were considered as an abnormal result in utero-placental perfusion. The prevalence of abnormal velocity wave forms in this risk group was higher than in a non-diabetic population. No significant correlation was found between abnormal Doppler studies and White's classification. Patients with vasculopathy represent a high-risk group for foetal growth retardation, which may be detected early by umbilical and especially uterine artery Doppler studies. Abnormal uterine and arcuate artery wave forms allowed identification of patients who developed pregnancy-induced hypertension/preeclampsia.

[The value of Doppler ultrasound studies of insulin-dependent diabetic patients]. / Die Wertigkeit dopplersonographischer Untersuchungen bei insulinpflichtigen Diabetikerinnen.

Measurement of umbilical, uterine and arcuate velocity waveforms was used to study 40 pregnancies complicated by insulin dependent diabetes. Continuous wave doppler velocimetry was used to identify flow velocity profiles during the second and third trimester of pregnancy. Resistance index (RI) was calculated to evaluate waveforms. In most of the patients with fetal growth retardation and/or pregnancy induced hypertension an increase in vessel resistance was found in uterine and arcuate arteries as well as diastolic notching. In comparison to that fact White's classification showed no significant correlation to vascular resistance determined by doppler flow measurement. This study indicates that doppler ultrasound examination may have an adjunctive role in the surveillance of pregnancies complicated by diabetes.

[The value of continuous wave Doppler ultrasound in risk pregnancy-intrauterine growth retardation and pregnancy-induced hypertension]. / Wertigkeit der Continuous-wave-Dopplersonografie bei Risikoschwangerschaft-intrauteriner Wachstumsretardierung und schwangerschaftsinduzierter Hypertonie.

To evaluate the frequency of abnormal doppler results in pregnancies complicated by placental insufficiency, flow waveforms of 100 patients with documented intrauterine growth retardation--birthweight below the 10th percentile--were analysed. Uterine, arcuate and umbilical artery velocimetry were performed by means of a continuous wave Doppler ultrasound. Neither the range of serial examination nor the interval between last prepartal doppler test und delivery showed influence on the doppler results. Compared to normal pregnancy, a significant increase of diastolic notching and incomplete registration of maternal vessels were found. Using 90th percentile as cut-off limit last doppler examination before delivery showed pathological results in 76% of all cases with growth retardation and 90% of pregnancies with an additional risk of pregnancy induced hypertension. As pathological waveforms in the maternal compartment contribute a major part to abnormal velocity waveforms, doppler study of utero-placental vessels plays an important role in the diagnose of impaired persuasion of the placenta.

[Discordant growth in twin pregnancy--value of Doppler ultrasound]. / Diskordantes Wachstum bei Geminigravidität--Stellenwert der Dopplersonographie.

A 4 MHz continuous-wave Doppler device was used to study uterine and umbilical arterial wave forms in 91 pairs of twins between 18th and 40th week of gestation. Biometry and cord localisation were effected by real-time ultrasound. The results of 182 Doppler flow examinations showed that umbilical flow velocimetry may prove relevant for early identification of twin pregnancies with discordant growth. Depending on the interval between examination and delivery, sensitivity and specificity values between 44% and 66%, and 66% and 73%, respectively, were obtained. A high resistance index in umbilical arteries was indicative of intrauterine growth retardation, at a specificity of 69% and a sensitivity of 44%. For uteroplacental as well as foetoplacental flow velocity waveform assessment, singleton reference values may be used, whereas, by reason of its low sensitivity, Doppler flow velocimetry does not lend itself as a primary diagnostic tool for intrauterine growth retardation. It can signal pathologic blood flow profiles, which are often associated with added risks, such as pregnancy-induced hypertension, foetal acidosis and stillbirth and can contribute to early detection of twin pregnancies that require close clinical and cardiotocographic surveillance.

Polynomial analysis of placental flow patterns in growth-retarded fetuses.

Correct interpretation of conspicuous blood flow velocity waveforms cannot rely solely on the evaluation of uteroplacental vascular Doppler flow patterns by means of angle-independent indices such as the resistance or pulsatility index. In addition to the degree of pulsatility, the waveform shape between the systolic and diastolic peak values is of considerable consequence. A subdivision of the total flow waveform into orthogonal polynomial components allows both pulsatility evaluation and notching to be registered, providing a higher sensitivity in identification of pathological vascular resistance. Accurate recording and assessment of the flow waveform is therefore an important qualitative criterion for the classification of Doppler flow patterns in pregnancies with reduced uteroplacental perfusion.

[Comparison of different blood flow parameters for evaluating blood flow spectra in fetal growth retardation]. / Vergleich unterschiedlicher Blutflussparameter zur Beurteilung von Blutflussspektren bei fetaler Wachstumsretardierung.

Uteroplacental and foetoplacental vascular resistance is generally high in pregnancies complicated by intrauterine growth retardation. Assessment of flow velocity curves using angle-independent indices as A/B ratio, resistance index (RI) or pulsatility index (PI) cannot classify all cases with pathological flow velocity profiles. Beneath the pulsatility the maximum frequency outline of the flow velocity waveform offers additional clinical information. The evaluation of flow velocity curves using polynome analysis (including III degrees) provides additional data including occurrence of diastolic notching and can be used as a more sensitive indicator of impaired uteroplacental blood flow. In such pregnancies accurate evaluation of the maximum flow velocity outline with polynome analysis has been shown to be an important qualitative criterion in the assessment of blood flow velocity waveforms.

[Uteroplacental circulation in growth retardation--experiences with the clinical use of continuous-wave Doppler]. / Uteroplazentare Durchblutung bei Wachstumsretardierung--Erfahrungen mit der klinischen Anwendung des Continuous-wave-Dopplers.

Doppler ultrasound measurement of blood flow velocity represents a non-invasive method of studying uteroplacental and feto-placental haemodynamics. Using a continuous-wave Doppler device, the blood flow velocity was examined in the uterine and arcuate arteries, as well as in the umbilical artery in 81 patients demonstrating fetal growth retardation. An increase in vessel resistance was found in the uterine and arcuate arteries in most of the patients. In addition, patients with fetal retardation showed a significantly higher rate of diastolic notching and incomplete registration of uterine and arcuate wave forms, especially in pregnancies complicated by hypertension. The implementation of the continuous-wave technique as a simple Doppler system allows differential evaluation of placental function and provides information on the nutritional supply to the fetus.

Uteroplacental diastolic notching in 510 uneventful pregnancies.

In a collective of 510 patients with uneventful pregnancies and deliveries the rate of waveform notching in the uteroplacental flow velocity pattern was examined. Notching appeared to be significantly more frequent in the uterine than arcuate artery. It was unilateral and mainly affected placenta-contralateral sites. Bilateral notching or notching on placental site were the exception. In both flow patterns notching was seen to increase as pregnancy progressed and was slightly higher in the third compared to the second trimester.

[Early diastolic incisures in uteroplacental blood vessels. Experiences in patients with uneventful pregnancy and labor]. / Frühdiastolische Inzisuren in uteroplazentaren Gefässen. Erfahrungen bei Patientinnen mit unauffälligem Schwangerschafts- und Geburtsverlauf.

The frequency of diastolic notching in uteroplacental arteries was examined in a collective of 510 patients with uneventful pregnancies and deliveries. Notching appeared to be more frequent in the uterine than arcuate artery. It was seen to increase as pregnancy progressed and was markedly higher in the third compared with the second trimester. Uteroplacental notching occurred more frequently unilaterally and mainly affected contralateral sites of the placenta. Bilateral and retroplacental notching was the exception in normal pregnancies.

[Evaluation of the pulsatile curve of the placental blood flow profile by polynomial analysis]. / Beurteilung der Hüllkurve plazentarer Blutströmungsprofile durch Polynomanalyse.

The analysis of uterine and umbilical blood flow velocities using A/B ratio, resistance index and pulsatility index has shown to be a highly specific and sufficiently sensitive method in the evaluation of high risk pregnancies. In situations of high peripheral vascular resistance diastolic velocities are low and index values are high. Additional information of flow velocities curves, as diastolic notching, is not represented in the indices commonly used. A mathematical model was established using polynom analysis of blood flow velocity curves. In a group of 78 patients with intrauterine growth retardation polynome analysis of uteroplacental flow velocity curves was more sensitive than resistance index and pulsatility index.

Reference values for resistance index and pulsatility index of uteroplacental Doppler flow velocity waveforms based on 612 uneventful pregnancies.

Using a 4-MHz continuous-wave Doppler device, standard rates were established for resistance index (RI) and pulsatility index (PI) of uterine and arcuate arteries of 612 patients with uneventful pregnancies and deliveries. From 18 to 41 weeks of gestation, neither RI nor PI of uterine or arcuate arteries proved to vary with gestational age, maternal heart rate, or maternal age. By contrast, a significant effect of placental location on the measurement results was found in both uterine and arcuate arteries. The differences between measurements on the placental or opposite site are more distinct in arcuate than in uterine arteries. Taking the 90th percentile as a localization gauge, cutoff levels of 0.52 (RI) and 0.98 (PI) were found in uterine arteries. In arcuate arteries, cutoff levels of 0.45 (RI) and 0.82 (PI) were found on the placental site or with a placenta without lateralization. On the nonplacental site of a lateralized placenta, the cutoff levels were 0.51 (RI) and 0.92 (PI).

[Obstetric cw-Doppler--results of a study of normal values. Effect of different variables on results]. / Geburtshilflicher cw-Doppler--Ergebnisse einer Normalwertstudie. Einfluss verschiedener Variablen auf das Messergebnis.

Using a 4 MHz continuous wave Doppler device reference values for resistance index (RI) and pulsatility index (PI) of uterine and arcuate arteries as well as umbilical artery were established based on 510 patients with uneventful pregnancies and deliveries. Percentiles are more suitable localisation gauge than are standard deviations. Neither RI nor PI of maternal arteries proved to be dependent on gestational age in the observation period. If the heart rate are in physiological ranges no clinically relevant effect on the results were observed in either the maternal of the foetal copartment. By contrast umbilical artery shows a definite linear relation between the indices measured and gestational age. A significant effect of placental site on the measurement was found in both, uterine and arcurate arteries, but only the differences found in arcuates were of clinical value. An increase of diastolic notching was observed in both, uterine and arcuate arteries during pregnancy. Mostly only one vessel showed diastolic notching when observed in normal pregnancy. With a lateralized placenta the condition was more probable on the contralateral site.