Biomedical subjects

S Droste

Publications and source records attributed to S Droste.

At least 19 recordsLinked to original sources

PubMed2001

Uterine rupture during second-trimester abortion associated with misoprostol.

BACKGROUND: Misoprostol use is contraindicated in women at term with a history of a uterine scar. There are limited data regarding the use of this drug in the midtrimester. CASE: A 23-year-old woman with two prior cesareans presented at 23 weeks' gestation for pregnancy termination by dilation and evacuation. She had laminariae placed the day before and was instructed to take 400 microg of misoprostol intravaginally at midnight, then 400 microg buccally at 6:00 AM the day of the procedure. During the evacuation, uterine rupture was diagnosed. She underwent emergency laparotomy, and the uterus was repaired. CONCLUSION: Uterine rupture can occur when misoprostol is used in the second trimester in a woman with a uterine scar.

Abortifacient Agents, Nonsteroidal↗

PubMed2001

[Rapid assessments"--quick evaluation of medical technology].

Assessing the clinical, economical and other consequences of medical technologies (health technology assessment, HTA) is an important instrument to support decisions in many health care systems. A comprehensive HTA, however, is time-consuming and costly while, on the other hand, decisions have to be made quickly. A number of international HTA programmes established rapid assessment tracks although they are variable in scope and methods. In the first part of this paper, these programmes were compared with respect to scope, methods and time to complete assessments. It can be shown from this comparison that there is no common definition of "rapid assessments". In the second part of the paper, a model for processing rapid assessment in the German context is introduced and discussed. The model aims at rapid assessments serving the needs of German decision-makers and ensuring high scientific quality at the same time. The model consists of a modular system that is tailored to the actual demand of the decision-maker. Modules are obligatory (such as a systematic literature search) or optional (such as meta-analysis). All modules are subject to standardisation as far as possible. However, it should be kept in mind that a close collaboration between commissioners and executives of an HTA is necessary to focus on the question and work out the HTA accordingly.

Cost-Benefit Analysis↗

PubMed2001

Stimulation of phagocytosis and free radical production in murine macrophages by 50 Hz electromagnetic fields.

Effects of 50 Hz electromagnetic fields on phagocytosis and free radical production were examined in mouse bone marrow-derived macrophages. Macrophages were in vitro exposed to electromagnetic fields using different magnetic field densities (0.5-1.5 mT). Short-time exposure (45 min) to electromagnetic fields resulted in significantly increased phagocytic uptake (36.3% +/- 15.1%) as quantified by measuring the internalization rate of latex beads. Stimulation with 1 nM 12-0-tetradecanoylphorbol-13-acetate (TPA) showed the same increased phagocytic activity as 1 mT electromagnetic fields. However, co-exposure to electromagnetic fields and TPA showed no further increase of bead uptake, and therefore we concluded that because of the absence of additive effects, the electromagnetic fields-induced stimulation of mouse bone marrow-derived macrophages does not involve the protein kinase C signal transduction pathway. Furthermore, a significant increased superoxide production after exposure to electromagnetic fields was detected.

Animals↗

PubMed2001

[Systematic literature search to make HTA (health technology assessment) reports].

Health technology assessment should describe the existing evidence of a medical technology independently and complete. Because of the enormous amount of scientific publications worldwide, systematic literature investigation is essential to identify all publications of relevance. Systematic investigation implies especially hierarchical and standardized modes. The most important resources to identify publications that already contain a synthesis of information are specialized databases covering secondary literature. A standardized search strategy consists of several steps: conception (incl. specification of methodological and content-related inclusion and exclusion criteria), selection of databases, preparation of a query, and carrying out the search, finally. The identified publications--this could be several hundreds up to some thousands--have to be assessed by applying the a priori defined criteria and a decision has to be made whether to include or exclude documents for the health technology assessment report.

Information Storage and Retrieval↗

PubMed2001

Color Doppler ultrasonography for distinguishing myomas from uterine contractions in pregnancy.

OBJECTIVE: To determine the applicability and reliability of color Doppler ultrasonography (US) for distinguishing a uterine myoma from a focal myometrial contraction. STUDY DESIGN: Images from 36 patients with uterine thickenings were classified as myomas when color Doppler US demonstrated no centralized flow with a circumscribed vessel pattern at the border. Thickenings were classified as focal myometrial contractions when there was demonstrable vascular flow throughout the thickening. RESULTS: Using these diagnostic criteria, images from 36 patients were reliably characterized as representing myomas or contractions. The diagnosis was made more reliable by using the lowest velocity settings and exclusion of power Doppler US in nonretroplacental lesions. CONCLUSION: Color Doppler US is a sensitive and reliable tool for distinguishing uterine myomas from focal myometrial contractions.

Adult↗

PubMed2000

The brain mineralocorticoid receptor: greedy for ligand, mysterious in function.

Glucocorticoids exert their regulatory effects on the hypothalamic-pituitary-adrenocortical axis via two types of corticosteroid receptors: the glucocorticoid receptor and the mineralocorticoid receptor. Whereas the glucocorticoid receptor has a broad distribution in the brain, highest levels of mineralocorticoid receptor are found in the hippocampus. Based on the differential occupancy profile by endogenous glucocorticoids, glucocorticoid receptors are thought to mediate negative feedback signals of elevated glucocorticoid levels, whereas mineralocorticoid receptors control the inhibitory tone of the hippocampus on hypothalamic-pituitary-adrenocortical axis activity. Dysfunction of mineralocorticoid receptors and glucocorticoid receptors are thought to be implicated in stress-related psychiatric diseases such as major depression. Because of its intriguing features, we focus in this review on the mineralocorticoid receptor and provide data which reveal novel aspects of the pharmacology and physiology of mineralocorticoid receptors. Newly obtained results are presented, which help to solve the paradox of why dexamethasone binds with high affinity to mineralocorticoid receptors in vitro, yet binds poorly in vivo. Until recently, mineralocorticoid receptor protein and mRNA levels could only be routinely studied with in vitro cytosol binding assays, in vitro and in vivo receptor autoradiography, Northern blot analysis, and in situ hybridization. These methods are unfortunately hampered by several flaws, such as the necessity of adrenalectomy, no or poor neuroanatomical resolution, the fact that mRNA does not provide the same information as protein, or combinations of these factors. We present immunohistochemical data on mineralocorticoid receptors in the brain obtained by using commercially available antibodies, which alleviate many of these shortcomings. Furthermore, an in vivo microdialysis method is presented which allows the assessment of free corticosterone levels in the brain, which is critical for the study of the pharmacological basis of mineralocorticoid receptor (and glucocorticoid receptor) function. Finally, a novel aspect of the regulation of mineralocorticoid receptors is described which provides evidence that this receptor system is dynamically regulated. In conjunction with previously reported effects of antidepressants, these results have initiated a new concept on the cause of the hypothalamic-pituitary-adrenocortical axis disturbances often seen in stress-related psychiatric disorders such as major depression.

Animals↗

PubMed2000

New mode of hypothalamic-pituitary-adrenocortical axis regulation: significance for stress-related disorders.

Two types of corticosteroid receptors have been identified in the brain and pituitary that play an important role in the regulation of the hypothalamic-pituitary-adrenocortical (HPA) axis. These glucocorticoid hormone binding receptors are the mineralocorticoid receptor (MR) and the glucocorticoid receptor (GR). Evidently, a tight control of the concentration and function of these receptors is of prime importance for maintaining and regaining homeostasis after stressful challenges. Here, we describe a novel mechanism revealing a rapid upsurge in MR density in the hippocampus (a limbic structure highly involved in HPA axis regulation) after an acute psychologically stressful challenge. This rise in MR is accompanied by a stronger MR-mediated inhibitory control of the HPA axis. Thus, an acute stressful experience results in a reorganization of the HPA axis involving a principal role of the hippocampal MR. This novel mechanism may be of significance for increasing our understanding of the etiology of stress-related disorders.

Animals↗

PubMed1999

Effect of hemodialysis on serum progesterone level in pregnant women.

The objective of this study is to evaluate the effect of chronic hemodialysis on serum progesterone level in pregnancy. Serum progesterone levels were measured predialysis and postdialysis using the radioimmunoassay technique in seven gravid women with renal failure requiring hemodialysis. Uterine contractions were measured before and after hemodialysis using home uterine activity monitoring (HUAM) in two patients. Thirty-three paired serum samples were obtained between 14 and 39 weeks' gestation. The mean change in serum progesterone level postdialysis throughout pregnancy ranged from -52.0% to +8.7% for each individual patient. The change in serum progesterone level was unrelated to gestational age. The woman experiencing the most significant decrease in serum progesterone level with dialysis continued her pregnancy to greater than 39 weeks. No significant increase in uterine contraction frequency was noted on HUAM postdialysis (P = 0.22), although both monitored patients experienced a small increase in serum progesterone levels. In conclusion, serum progesterone values showed a variable patient-specific response when measured predialysis and postdialysis in pregnancies complicated by renal failure. There was no significant increase in uterine activity noted postdialysis. Progesterone withdrawal does not appear to explain the increased frequency of preterm delivery in women after dialysis.

Female↗

PubMed1998

A rigorous complexity analysis of the (1 + 1) evolutionary algorithm for separable functions with Boolean inputs.

Evolutionary algorithms (EAs) are heuristic randomized algorithms which, by many impressive experiments, have been proven to behave quite well for optimization problems of various kinds. In this paper a rigorous theoretical complexity analysis of the (1 + 1) evolutionary algorithm for separable functions with Boolean inputs is given. Different mutation rates are compared, and the use of the crossover operator is investigated. The main contribution is not the result that the expected run time of the (1 + 1) evolutionary algorithm is theta (n ln n) for separable functions with n variables but the methods by which this result can be proven rigorously.

Algorithms↗

PubMed1995

Fetal response to carbon dioxide pneumoperitoneum in the pregnant ewe.

OBJECTIVE: To determine the effects of maternal abdominal carbon dioxide (CO2) insufflation on placental blood flow and fetal blood gas measurements in the pregnant ewe. METHOD: Five time-bred ewes at 110 days' gestation were surgically prepared with maternal and fetal catheters placed for subsequent measurement of vascular pressures, blood gas tensions, and placental blood flows. On surgical recovery day 3, the ewe was anesthetized, placed on her right side, intubated, and manually ventilated to maintain a constant maternal carbon dioxide pressure (PCO2) range (37.1 +/- 3.3 mmHg) for the duration of the experiment. The maternal abdomen was inflated with CO2 to maintain an intraabdominal pressure of 20.7 +/- 0.6 mmHg. Maternal and fetal blood flows and blood gases were determined at 30 minutes of ventilation, 60 minutes of insufflation, and 40 minutes of desufflation. Simultaneous maternal and fetal organ blood flows were determined using the radioactive microsphere technique. RESULTS: Maternal perfusion pressure fell 22% (P = .01) in response to insufflation, whereas pressure in the inferior vena cava rose 53% (P = .003). Maternal placental blood flow fell to 61% (P = .002) of control. Seventy-seven percent of this blood-flow change was in response to the decreased perfusion pressure, with 23% resulting from an increased placental vascular resistance of 32% (P = .02). Maternal blood gas values did not change with insufflation or desufflation. Despite the marked decrease in maternal placental blood flow, the fetal placental perfusion pressure and blood flow, pH, and blood gas tensions were unaffected by insufflation or desufflation. CONCLUSION: The sheep fetus has sufficient placental flow reserves or compensatory responses to maintain adequate gas exchange during a 1-hour, 20 mmHg maternal pneumoperitoneum. Laparoscopic surgical procedures may prove to be a safe alternative to laparotomy during pregnancy.

Animals↗

PubMed1994

Expectant management of placenta previa: cost-benefit analysis of outpatient treatment.

OBJECTIVE: In this study outpatient and inpatient expectant management for complete placenta previa were compared in terms of maternal and neonatal outcome and overall cost. STUDY DESIGN: We reviewed the outcomes and hospital costs of 72 mother-infant pairs where the pregnancy was complicated by second- or third-trimester placenta previa and was managed expectantly either with hospitalization or outpatient bed rest. The data were analyzed with the two-sided unpaired t test, chi 2, and simple correlation analysis. RESULTS: There were no differences in maternal morbidity as measured by estimated total blood loss, number of blood transfusions, nadir hematocrit, or need for emergency delivery. Fetal mortality was comparable in both groups, and there were no significant differences in neonatal morbidity as measured by gestational age, birth weight, 5-minute Apgar score, or occurrence of fetal distress. Among outpatients the number of maternal hospital days was reduced by 50% (p < 0.01). Outpatient management achieved a hospital cost reduction of 48.5% for mothers (p < 0.001) and 39.4% for mother-infant pairs (p < 0.05). CONCLUSION: In selected patients outpatient management of complete placenta previa can be cost-effective and safe.

Adult↗

PubMed1993

Prenatal diagnosis and a donor splice site mutation in fibrillin in a family with Marfan syndrome.

The Marfan syndrome, an autosomal dominant connective tissue disorder, is manifested by abnormalities in the cardiovascular, skeletal, and ocular systems. Recently, fibrillin, an elastin-associated microfibrillar glycoprotein, has been linked to the Marfan syndrome, and fibrillin mutations in affected individuals have been documented. In this study, genetic linkage analysis with fibrillin specific markers was used to establish the prenatal diagnosis in an 11-wk-gestation fetus in a four-generation Marfan kindred. At birth, skeletal changes suggestive of the Marfan syndrome were observed. Reverse transcription-PCR amplification of the fibrillin gene mRNA detected a deletion of 123 bp in one allele in affected relatives. This deletion corresponds to an exon encoding an epidermal growth factor-like motif. Examination of genomic DNA showed a G-->C transversion at the +1 consensus donor splice site.

Adult↗

PubMed1992

Maternal and fetal hemodynamic effects of autologous blood donation during pregnancy.

OBJECTIVES: Our objectives were to describe the maternal and fetal hemodynamic impact of a 1 U acute blood loss during pregnancy and to compare the hemodynamic responses of pregnant women with those of nonpregnant controls. STUDY DESIGN: With Doppler techniques cardiac output and total peripheral vascular resistance were determined in 16 pregnant women in the third trimester and in 16 nonpregnant volunteers before and during orthostatic stress, before and after donation of 450 ml of whole blood. In pregnant women the fetal umbilical artery systolic/diastolic ratio was also determined. Data were subjected to multiple logistic regression analysis. RESULTS: In both groups orthostasis provoked significant decreases in cardiac output and increases in total peripheral vascular resistance. The hemodynamic effects of blood loss were less pronounced and did not significantly change the hemodynamic response to orthostasis in either group. Neither orthostasis nor blood loss caused significant changes in the umbilical systolic/diastolic ratio. CONCLUSION: These data support the hemodynamic safety of uncomplicated autologous blood donation during late pregnancy.

Blood Donors↗

PubMed1992

Fetal growth in aneuploid conditions.

Fetal growth failure is a significant clinical problem. Although aneuploid conditions account for only a few cases of intrauterine growth retardation, the clinical importance of these conditions is profound. Recognition of aneuploidy demands a high index of suspicion from the clinician and some knowledge of the growth patterns associated with these syndromes (Table 3). Symmetric growth retardation as a clinically recognizable entity probably does not exist. However, variations in the growth patterns in different aneuploidies may add important diagnostic clues to the evaluation of the growth-retarded fetus. In addition a better understanding of these patterns and their regulation may provide insight into the mechanisms, not only of abnormal, but perhaps more importantly, of normal fetal growth and development.

Aneuploidy↗

PubMed1991

Cystic hygroma colli: perinatal outcome after prenatal diagnosis.

Prenatally diagnosed cystic hygroma colli is associated with Turner syndrome, but has been reported with a variety of other conditions. The association with abnormal karyotypes frequently results in a decision to terminate the pregnancy. Information on the natural history of this malformation is thus limited. We reviewed 34 cases of cystic hygroma colli which were diagnosed by ultrasound at a mean gestational age of 17.3 +/- 3.4 weeks. Pregnancy outcome was known for 31 of these cases. The distribution of fetal karyotypes, available for 23 fetuses, was similar to that reported in other series. Only two fetuses, both with an abnormal karyotype, were liveborn at term. Fourteen pregnancies were electively terminated while the remaining 15 cases resulted in spontaneous pregnancy loss. Twenty-six fetuses underwent necropsy which generally confirmed the prenatal ultrasound findings. However, in 9 cases associated anomalies had been missed by the sonogram. Only one fetus with associated anomalies survived to term. Hydrops was common and occurred in most of the spontaneous losses. This series suggests that the prenatal finding of cystic hygroma colli portends an extremely poor prognosis regardless of the karyotype or the presence or nature of associated anomalies. We confirm that karyotypes other than monosomy X are common and that perinatal survival is highly unlikely, especially in the presence of hydrops fetalis.

Down Syndrome↗

PubMed1990

Growth failure in second-trimester fetuses with trisomy 21.

Growth failure in the Down syndrome is common postnatally, but is thought to be less consistent in fetuses and newborns. We describe the growth of individual organs in 53 second-trimester abortuses with trisomy 21 and compare the organ weights to organ weights from 432 spontaneously aborted, but otherwise normal control specimens. Using multiple regression analysis, we found body weight to be the most significant predictor of all organ weights in normal fetuses; therefore, this variable was used to generate the regression lines to which the organ weights of trisomic specimens were compared. All trisomic fetal organs were found to be small, with an abnormal karyotype being a significant predictor of low organ weight. However, the effect on individual organs was variable, with some organs differing only minimally from the controls. Placental weights were not affected by fetal trisomy. This study demonstrates the presence of well-established, although variably severe, growth retardation in second-trimester fetuses with Down syndrome.

Body Height↗

PubMed1990

Growth of linear parameters in trisomy 18 fetuses.

Linear growth in fetuses with trisomy 18 has not been systematically described. We studied the relationship between long-bone, crown-rump, and foot length and gestational age in 17 postmortem fetal specimens with this syndrome. Long-bone and crown-rump lengths were compared with normal regression lines and foot length was compared with gestational age determined on the basis of menstrual dates. Correlation between foot length and menstrual dates was weak in trisomy 18. Gestational age predicted by crown-rump length was significantly lower than gestational age by menstrual dates. All long bones were significantly shortened and fell below normal regression lines for gestational age. The fetal femur/foot length ratio was reduced. Thus no endogenous measure of gestational age appears to exist in this aneuploidy, forcing reliance on menstrual dates. The observed pattern of growth alterations will likely preclude the development of a gestational age-dependent biometric screen for the prenatal detection of this syndrome.

Bone and Bones↗

PubMed1990

Size of the fetal adrenal in bilateral renal agenesis.

Bilateral renal agenesis is a fetal malformation incompatible with extrauterine life. Accurate prenatal diagnosis is essential for patient counseling. False-negative diagnoses have been reported and were attributed to the sonographic misidentification of apparently hypertrophied fetal adrenal glands as fetal kidneys. To study the relationship between renal agenesis and adrenal size, we reviewed autopsy records from 11 affected fetuses that had undergone careful autopsy and organ weight determination in our laboratory. Anomalies of distant structures were present in five affected fetuses. A sonographic diagnosis of adrenal hypertrophy had been made in two cases. In four of 11 fetuses, the glands had taken on a flattened discoid appearance. The autopsy records of 240 normal fetuses were similarly reviewed, and regression lines were generated for adrenal weight based on foot length and crown-rump length. The adrenal weights from affected fetuses were well within normal limits when compared with these normal regression lines and with organ weight standards from the literature. We conclude that adrenal hypertrophy is not a common finding in this syndrome and that the reported false-negative diagnoses are more likely attributable to a change in adrenal shape rather than a true increase in adrenal mass.

Abnormalities, Multiple↗