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Biomedical subjects

F A Van Assche

Publications and source records attributed to F A Van Assche.

At least 55 records · Page 3Linked to original sources
PubMed1998

Alternative technique for Nd: YAG laser coagulation in twin-to-twin transfusion syndrome with anterior placenta.

Nd: YAG laser coagulation is used to treat severe twin-to-twin transfusion syndrome (TTS). Success of the technique depends on visualization of the placenta, the fetal membranes and the targeted vessels, as well as obtaining an optimal inclination angle for laser coagulation. In the rare case of an extensive anterior placenta, it may be difficult to achieve these conditions using the percutaneous approach. Here, we propose an alternative to the percutaneous procedure. Modifications involve an open access and the use of a flexible cannula and bent scope. An extraplacental area, usually at the fundus, is identified by B-mode and color Doppler imaging. A mini-laparotomy is made under general anesthesia. The viscera are retracted and the cannula is inserted under direct view and ultrasound control by the Seldinger technique. The curved fiberscope is passed through the flexible cannula, allowing adequate inspection of the placenta, and target vessels can be coagulated at an angle close to 90 degrees. After the procedure, the uterus is closed primarily to prevent postoperative leakage of amniotic fluid or hemorrhage. This technique has been successfully used in six patients with TTS and a completely anterior placenta, with a gestational age between 18.5 and 22.0 weeks. In all patients, the amniotic cavity was accessed without hemorrhage. The outcomes are similar to those published previously for laser coagulation. The mean interval from intervention until delivery was 10.5 weeks. All 12 fetuses were live born but four died from complications of extreme prematurity. No maternal complications occurred.

Female↗
PubMed1998

Fetal growth and consequences for later life.

There is evidence that an abnormal intrauterine environment has consequences for later life. Intrauterine growth retardation is associated with low insulin secretion during fetal life and probably a reduced development of insulin receptors. In later life these alterations can induce insulin resistance. Macrosomia is associated with an increased insulin secretion during fetal life and exhaustion of the insulin producing B cells. In later life a reduced insulin secretion is found. The working mechanisms have been explored in experimental studies. Normalisation of the diabetic intrauterine milieu can prevent consequences in later life. There are also indications that vascular changes in later life can be reduced by anti-oxidantia. In the human intrauterine growth retardation is related in later life with insulin resistance, vascular diseases and preeclampsia; macrosomia is related with gestational diabetes and breastcarcinoma.

Animals↗
PubMed1998

Fetal growth and development.

The foetal growth is, for the greater part, determined genetically. There are, however, favouring and inhibiting factors, which influence this growth. In such a matter, the mother, the placenta and the foetus play an important part. The mother shows as well metabolic as vascular adaptations. The placenta must let through nutrients and oxygen; the uteroplacental circulation is characterized by a high flow, together with a low vascular resistance. The foetus itself plays an important part owing to its own growth factors. The principal growth factors are insulin and the growth factors analogous to insulin. The slowing up of the intra-uterine growth is the consequence of genetic factors or of the decrease of the growth-potential. The real cause is, however, mostly a decrease of the vascular adaptation in the mother or a diminution of the uteroplacental circulation. The vascular causes usually induce an asymmetrical delay in the growth; foetal causes induce a symmetrical retardation. An exaggerated growth of the foetus--or macrosomy--is mostly due to an excessive inflow of nutrients: this is the case when a pregnant woman is suffering from diabetes. During the former years, it has become evident that abnormalities of the foetal growth influence the later life of people.

Animals↗
PubMed1997

Effect of antenatal thyrotropin-releasing hormone on uterine contractility, blood pressure, and maternal heart rate.

OBJECTIVE: The goal was to study the effects on uterine contractility, blood pressure, and heart rate of thyrotropin-releasing hormone given antenatally in combination with glucocorticoids to accelerate fetal maturation. STUDY DESIGN: A placebo-controlled, randomized, double-blind study was performed involving 30 women whose pregnancies were followed up at the University Hospital Gasthuisberg in 1994 and 1995. RESULTS: Thyrotropin-releasing hormone induced a significant mean increase of nearly 6 mm Hg in systolic blood pressure and approximately 5 mm Hg in diastolic blood pressure. The duration of this raise was < 20 minutes. Thyrotropin-releasing hormone had no significant effect on maternal heart rate or uterine contractility: 4.2 +/- 1.6 contractions per hour before versus 4.7 +/- 1.7 contractions per hour after treatment. CONCLUSIONS: Thyrotropin-releasing hormone induces a small (mean < 6 mm Hg) and brief mean (< 20 minutes) increase in blood pressure but appears to have no clinically detectable effect on uterine contractility.

Blood Pressure↗
PubMed1997

Detection of immunoreactive interleukin-11 in human follicular fluid: correlations with ovarian steroid, insulin-like growth factor I levels, and follicular maturity.

OBJECTIVE: To prove the presence of interleukin-11 (IL-11) in the follicular fluid (FF), to determine its source and the correlation between IL-11 and fertilization outcome, follicular size, number of follicles per patient, steroids, and insulin-like growth factor-1 (IGF-I) levels. DESIGN: Interleukin-11 levels were measured in FFs, aspirated during oocyte pickup for IVF. SETTING: Academic hospital and research environment. PATIENT(S): Follicular fluid and serum were obtained with informed consent from 44 patients undergoing IVF-ET. Granulosa cells were isolated from 17 patients. MAIN OUTCOME MEASURE(S): We hypothesized that IL-11 might play a role in follicular development, as do other related cytokines present in FF. Interleukin-11 was measured with ELISA. RESULT(S): Interleukin-11 was absent in the serum but present in FF and in conditioned medium from granulosa cells. Atretic follicles had higher concentrations of IL-11. No correlation was found between IL-11 and fertilization outcome, follicular size, steroid, IGF-I, and total protein concentrations. CONCLUSION(S): We conclude that IL-11 is present in FF. The role of IL-11 in follicular development should be the object of further investigations.

Biomarkers↗
PubMed1997

The endocrine pancreas in virgin and pregnant offspring of diabetic pregnant rats.

Diabetes of the mother during pregnancy induces structural and functional adaptations in the fetal endocrine pancreas. We have previously shown in our experimental rat model, that the impact of this abnormal intra-uterine milieu leads, in the adult offspring, to a disturbance of the glucose homeostasis and to the development of gestational diabetes. The aim of the present work is to investigate wether these functional differences can be explained by structural differences at the level of the endocrine pancreas. Therefore the size and the structure of the endocrine pancreas, as well as the contribution of the insulin-, glucagon-, somatostatin- and PP-cells, were investigated morphometrically in the adult youngsters of mildly and of severely diabetic mothers, since both display a disturbed glucose tolerance but with divergent characteristics. Also the adaptation of their endocrine pancreas to pregnancy was measured and compared to that of a control pregnancy. In the offspring of mildly diabetic mothers, the size of the endocrine pancreas and the distribution of the islets of Langerhans are normal. Also the doubling of the endocrine mass during pregnancy is similar to controls. The high proportion of A-cells, especially in relation to a normal B-cell mass and the low amount of PP-cells, might play a role in the impairment of the insulin response in these animals and in the development of gestational diabetes. In the offspring of severely diabetic mothers a clear hypertrophy of the endocrine pancreas is noted, which is mainly due to the presence of numerous small islets and which does not increase further during pregnancy. In these animals, the size of the endocrine pancreas and of the B-cell mass have reached 'pregnant' values without pregnancy, which coincides with an exaggerated insulin output and peripheral insulin resistance, as during normal pregnancy. No further increase in islet mass is seen during pregnancy, which is associated with gestational diabetes.

Animals↗
PubMed1997

Maternal semistarvation and streptozotocin-diabetes in rats have different effects on the in vivo glucose uptake by peripheral tissues in their female adult offspring.

Previous work in humans and rats has revealed a link between perinatal growth retardation and glucose intolerance in adulthood. Both maternal semistarvation and severe diabetes are accompanied by perinatal growth retardation in rats. In this study, we compared the effect of these conditions on tissue glucose uptake in their female offspring. Glucose uptake was measured as glucose metabolic index (GMI), using 2-deoxy-[1-3H]-glucose, in the postabsorptive state and during euglycemic hyperinsulinemia. The GMI was measured in insulin-sensitive tissues (5 skeletal muscles, diaphragm and white adipose tissue) and in two noninsulin-sensitive tissues (duodenum and brain) of adult offspring of normal dams, dams rendered diabetic with streptozotocin on d 11 of pregnancy, and dams fed half normal rations from d 11 of pregnancy. Whole-body insulin resistance, measured by decreased glucose infusion rate during hyperinsulinemia, was milder in offspring of semistarved rats (O-SR) than in offspring of diabetic rats (O-DR). The basal GMI did not differ among the three groups in any tissue except tibialis anterior; during hyperinsulinemia, GMI was significantly greater in the insulin-sensitive tissues of all three groups. GMI of skeletal muscles and adipose tissue during hyperinsulinemia did not differ between control rats and O-SR; in contrast, the GMI was 25-50% lower in skeletal muscles of O-DR during hyperinsulinemia than in those of control rats or O-SR. Thus, maternal semistarvation and diabetes have dissimilar effects on peripheral insulin sensitivity of the adult female offspring. Because both conditions are associated with perinatal growth retardation and fetal hypoinsulinemia, other mechanisms must be identified to explain impaired glucose uptake by skeletal muscles in the offspring of diabetic rats.

Adipose Tissue↗
PubMed1996

Attachment and differentiation in vitro of trophoblast from normal and preeclamptic human placentas.

OBJECTIVE: Trophoblast from preeclamptic patients shows impairment of various functions, including restricted invasive behavior of extravillous trophoblast. In this light the effect of different matrix components on attachment and differentiation of primary trophoblast cultures derived from normal and preeclamptic pregnancies was investigated. STUDY DESIGN: Trophoblast was isolated from placentas of normotensive (n = 5) and preeclamptic patients (n = 5) and cultured up to 7 days on LabTek slides precoated with fibronectin, laminin, or vitronectin. Attachment was evaluated 24 hours after plating, the degree of syncytialization was evaluated, and slides were immunocytochemically stained for cytokeratin, vimentin, human chorionic gonadotropin, and human placental lactogen. RESULTS: Trophoblast from placentas of preeclamptic patients showed a significantly lower attachment on fibronectin and vitronectin compared with controls. Diminished multinuclear cell formation was found on uncoated and laminin-coated slides in preeclamptic cases. No difference was found in the percentage of human chorionic gonadotropin- and human placental lactogen-positive cells between groups. CONCLUSIONS: Lower trophoblast attachment on fibronectin and vitronectin was observed in preeclamptic pregnancies, which may reflect differences in expression of matrix receptors. Lower syncytialization of trophoblast in this group indicates an intrinsic defect in differentiation, but otherwise no differences were found in differentiation between normotensive and preeclamptic patients.

Adult↗
PubMed1996

Langerhans' cells and L1 antigen expression in normal and abnormal squamous epithelium of the cervical transformation zone.

This study evaluates the presence of Langerhans' cells and expression of L1 antigen in squamous epithelium of the normal and dysplastic transformation zone of the cervix uteri and determines the influence of tobacco smoking and pregnancy. Women who smoked and pregnant women showed a decrease of Langerhans' cell counts in normal epithelium. In cervical intraepithelial neoplasia (CIN) 1 lesions, decreased Langerhans' cell counts were noted. L1 antigen expression was significantly less in CIN of all grades. Normal squamous epithelium of smokers showed weaker staining for L1 antigen but total staining scores were not significantly different. These data suggest a decrease in epithelial cell-mediated immune response in smokers, pregnant women and in low-grade CIN. Dysplastic squamous cells probably have intracellular regulatory problems independent of other immune cells.

Adult↗
PubMed1996

Cervical cotinine and macrophage-Langerhans cell density in the normal human uterine cervix.

Cotinine levels in blood and cervical fluid of smokers and non-smokers were analysed using capillary-column gas chromatography. These levels were not related to numerical cell densities of intraepithelial S100-protein- and LN2-positive Langerhans cells or to MAC-387-positive macrophages in the stroma of the transformation zone of normal uterine cervices. A decrease in the number of Langerhans cells was noted in smokers, especially in those using oral contraceptives (OCs). Macrophages were more numerous in the endocervical stroma of smokers, suggesting a local response to smoke constituents. These findings may indicate a synergistic suppression of local cervical immunity by smoking and OCs.

Adult↗
PubMed1996

[Diabetes and pregnancy].

Diabetes and pregnancy are associated with an increased incidence of preeclampsia. The pathogenesis is not exactly known. However endothelial factors and more special the prostacyclin-thromboxane system may be involved. Perinatal morbidity and mortality is increased in a diabetic pregnancy implicated with preeclampsia. Prevention and a curative approach is necessary.

Angiotensin II↗
PubMed1995

Renin-like immunoreactivity in human placenta and fetal membranes.

Five antibodies that stained renin in the kidney were used to investigate the presence of renin in human placenta and fetal membranes. Despite a large number of experimental approaches to enhance penetration of the immunoglobulins, only two of them showed immunostaining in placenta and fetal membranes. Staining was found in placental syncytiotrophoblast, the amnionic epithelium overlying the placenta, and in glandular epithelial cells present in the decidua adhering to the fetal membranes. It was most consistent, however, in a small infiltrating cell type dispersed through the fetoplacental layers. The two antibodies that revealed immunostaining in all preparations showed high affinity cross-reactivity with cathepsin D. Among other, less plausible, explanations, this raises the possibility that the bulk of 'renin' found in placenta and fetal membranes is not identical to renal renin, but may be cathepsin D or a substance related to both cathepsin D and renin.

Animals↗
PubMed1995

Intrauterine endoscopic creation of urinary tract obstruction in the fetal lamb: a model for fetal surgery.

OBJECTIVE: Our purpose was to evaluate the feasibility of intrauterine endoscopic fetal surgery in a fetal lamb model by creating a urinary tract obstruction. STUDY DESIGN: Lower urinary tract obstruction was created by ligation of the urethra and urachus in 21 fetal lambs, eight at 95 to 105 days' gestation (term 145 days) and 13 at 70 to 75 days. The endoscopic approach consisted of a 0-degree 5 mm telescope, three 5 mm cannulas, uterine distention by amnioinfusion, and adapted instrumentation. Intrauterine fetal monitoring included temperature and pulse oximetry registration. RESULTS: In 20 cases the urachus could be identified and ligated inside the umbilical cord. The urethra was ligated in the anterior abdominal wall (n = 7) or obstructed at the level of the penis (n = 13). Mean fetal heart rate was 147 +/- 35 beats/min, and fetal temperature at the end of intervention was 38.14 degrees +/- 2.1 degrees C. The overall postoperative survival rate was 76%. CONCLUSION: Urinary tract obstruction can be created endoscopically in the fetal lamb. This operation can serve as a model for endoscopic fetal surgery.

Animals↗