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Biomedical subjects

D Tibboel

Publications and source records attributed to D Tibboel.

At least 109 records · Page 6Linked to original sources
PubMed1996

Etiologic and genetic factors in congenital diaphragmatic hernia.

The cause of CDH remains largely unknown. Although teratogenic factors have been described, no single gene mutation can be held responsible for this major congenital anomaly. The genetic background of familiar occurrence is variable. Careful documentation of both isolated and familiar cases, and the application of new techniques such as fluorescent in situ hybridization (FISH) and differential display in selected cases, might result in new explanations for possible genetic inheritance. Clinical evaluation of associated anomalies, together with increasing awareness of the genes involved in lung development, especially those guiding mesenchymal growth, will have great impact on increasing knowledge of the cause of this devastating anomaly.

Abnormalities, Multiple↗
PubMed1995

Hepatic artery ligation for hepatic vascular tumors with arteriovenous and arterioportal venous shunts in the newborn: successful management of two cases and review of the literature.

The authors report their experience with hepatic artery ligation in two newborns, as well as relevant findings from a literature review. A 2-day-old boy had progressive cardiac and respiratory difficulty. A firm liver was palpable, with an overlying thrill. Sonography and arteriography showed diffuse arteriovenous shunting in both liver lobes. Hepatic artery ligation provided remarkable hemodynamic and clinical improvement. Another boy was admitted 3 weeks after birth because of bilious vomiting with abdominal distension and bloody stools. Abdominal examination showed a large liver with a systolic bruit and thrill. X-rays showed cardiac enlargement and dilated bowel loops with air-fluid levels. Arteriography and sonography showed arteriovenous and arterioportal venous shunting. Laparotomy was performed, and a large vascular malformation was palpated in both liver lobes. The entire bowel was congested and cyanotic, but there were no signs of obstruction. This patient had acute portal hypertension imitating intestinal obstruction. Ligation of the hepatic artery improved the color of the bowel, and the thrill disappeared. Five and nearly 4 years after the operation, both boys are growing normally without medication or diet. Sonography showed almost complete resolution of the hemangiomas.

Arteriovenous Malformations↗
PubMed1995

Amnio-allantoic fluid exchange for the prevention of intestinal damage in gastroschisis: an experimental study on chick embryos.

In gastroschisis, the protruding intestine is usually shortened, thickened, and covered with a fibrous peel. Urine components, which are increased in the amniotic fluid with the onset of renal function, are responsible for these changes. In the chick embryo model of gastroschisis, the authors performed amnio-allantoic fluid exchange to reduce the effect of urinary products. There were three study groups: control, gastroschisis only, and gastroschisis plus exchange. There was a significant decrease in creatinine (P < .05) and a slight decrease in urea concentrations in the gastroschisis-plus-exchange group compared with the gastroschisis-only group. Whereas macroscopic and microscopic studies showed severe fibrosis and bowel-wall thickening in the latter group, the bowel was normal or slightly oedematous in the former. On the basis of this study, the authors suggest that antenatal amniotic fluid exchange might reduce the bowel damage in human foetuses.

Abdominal Muscles↗
PubMed1995

Prospective evaluation of the absorptive capacity of the bowel after major and minor resections in the neonate.

The outcome after major bowel resection in the neonatal period depends primarily on the time needed for bowel adaptation. A prospective study was begun in neonates after small bowel resection to evaluate the absorptive capacity of the bowel and growth parameters as a result of adaptation of the bowel. Twenty-four neonates who underwent bowel resection were included. The underlying diagnoses were necrotising enterocolitis (12), jejunal atresia (3), meconium peritonitis (3), and other (6). During the study, a standardized treatment with respect to nutrition was followed. At predetermined times, enterostomy fluid or faeces were collected for analysis of carbohydrate content, fat content, and fatty acids, together with a xylose test and a hydrogen breath test. Growth parameters included weight and height. The 24 patients were divided into two groups. Group A consisted of eight patients with short bowel syndrome (defined as loss of more than 50% of the original small bowel length related to gestational age). The mean remaining small bowel length in this group was 34.0% (24% to 42%). Group B consisted of 16 patients who had only minor bowel resections. Retarded growth was observed in four group A patients. Low levels of carbohydrate absorption were found 2 and 4 weeks after the initial operation in group A, and 2 weeks after the initial operation in group B. Low levels of fat absorption were found 4 and 8 weeks after the initial operation in group A. The coefficient of absorption of the different fatty acids showed complete absorption of caprylic acid.(ABSTRACT TRUNCATED AT 250 WORDS)

Case-Control Studies↗
PubMed1995

Pulmonary neuroendocrine cells in neonatal rats with congenital diaphragmatic hernia.

Lung hypoplasia and persistent pulmonary hypertension are the principal causes of high mortality and morbidity in infants with congenital diaphragmatic hernia (CDH). Amine- and peptide-producing pulmonary neuroendocrine cells (PNEC), widely distributed throughout the airway mucosa, are thought to play an important role in both pulmonary development and regulation of pulmonary vascular tone. Furthermore, recent studies show increased levels of calcitonin gene-related peptide (CGRP), a pulmonary vasodilator produced by PNEC, during chronic hypoxia. The article reports data on morphometric analysis of CGRP immunoreactive PNEC clusters (neuroepithelial bodies, NEB) in a rat model of CDH. CDH was induced in neonatal Sprague Dawley rats by oral administration of 2,4-dichloro-phenyl-p-nitrophenylether (Nitrofen; Rohm Haas, Philadelphia, PA) to the mother at 10 days of gestation. Sections of lungs from term neonatal rats with and without CDH and controls were immunostained for CGRP (marker of NEB) with specific antibody against rat CGRP. NEB size and number of NEB/area of lung were assessed using a semiautomatic image analysis system. In lungs of neonatal rats with CDH, the number of NEB per surface area of lung parenchyma was significantly increased compared with the age-matched controls. Although the mean size of NEB was larger in CDH, the differences were not significant. This is the first study of PNEC in CDH. Whether the phenomenon observed in this study results in altered NEB function including imbalance in vasoactive mediators requires further studies, especially in the human being.

Animals↗
PubMed1995

A lack of intestinal pacemaker (c-kit) in aganglionic bowel of patients with Hirschsprung's disease.

Recent experimental studies in mice have shown that the proto-oncogene c-kit plays a key role in the development of a component of the pacemaker system that is required for generation of autonomic gut motility. These studies further suggest that interaction of the c-kit receptor and its ligand (stem cell factor, SCF) is critical for the development of the enteric nervous system. The authors investigated the presence of c-kit-positive (c-kit+) cells as well as the expression of SCF in bowel from 12 patients with Hirschsprung's disease (HD), 4 patients with total colonic aganglionosis (TCA), 2 patients with extensive aganglionosis (EA) and 14 controls. Our methods involved the use of immunohistochemistry with antihuman c-kit sera and antihuman SCF sera. A few c-kit+ cells were found in the muscle layers of aganglionic bowels from HD, TCA and EA, in contrast to many c-kit+ cells in ganglionic bowel segments from control, HD, and TCA patients. Expression of SCF was identified in the muscle layers as well as in myenteric plexus of ganglionic bowel, in contrast to its absence in the muscle layers of aganglionic bowel specimens. A lack of c-kit and SCF might be of significance for autonomic gut dysmotility in aganglionic bowel segments of patients with HD and allied disorders such as chronic idiopathic intestinal pseudo-obstruction.

Cell Adhesion Molecules↗
PubMed1995

Rotation of the gut: fact or fantasy?

Clinicians, as well as embryologists, believe that normally a process of rotation of the midgut takes place that can be hampered at any stage resulting in the different types of "malrotations." However, a "malrotated" gut has never been observed in normal embryos. Therefore all theories on the normal and abnormal development of the gut are still highly hypothetical. In an attempt to elucidate more clearly which events occur during the development of the gut, the authors studied its embryology in 58 normal rat embryos between the 13th and 20th day of gestation using scanning electron microscopy. In 13 day old rat embryos, the midgut has already formed a loop. It can be subdivided into three parts: the central part with its connections to the stomach and leading to the straight part, with the colorectum on the left and the "small bowel" on the right, and the tip of the loop inside the umbilical cord. These three parts show no signs of developmental synchronization. Each part develops according to its own developmental blueprint: the duodenal and umbilical parts of the midgut show much developmental activity, whereas gross changes of the straight part of the midgut are not seen. This finding is surprising because a process of rotation, if occurring, should result in notable morphological changes especially in this region. Furthermore, the coecum never achieved a position in the upper left abdomen, as is often outlined in schematic drawings. After the return of the bowel into the abdominal cavity, the coecum lies exclusively on the right side of the midline close to the ventral abdominal wall.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

End-of-life decisions for surgical neonates: experience in The Netherlands and United States.

PURPOSE: To characterize end-of-life decisions for surgical neonates and compare similarities and differences in practice between pediatric surgeons in The Netherlands and the United States. METHODS: The authors evaluated the deaths of all neonates admitted to the surgical intensive care unit (SICU) of two major children's hospitals: Sophia Children's Hospital (SCH) in The Netherlands and Columbus Children's Hospital (CCH) in the United States. Between January 1990 and July 1993, neonatal SICU admissions totaled 362 (SCH) and 125 (CCH). Neonates who died were classified as follows: group 1 = poor prognosis, expected death, and group 2 = good prognosis, expected survival. RESULTS: The mortality rates were comparable for each SICU: 12% (SCH) and 14% (CCH). The average survival period was shorter in group 1 (1.5 days) than in group 2 (26.5 days). Criteria for assignment to group 1 differed, with "expected poor quality of life" used at SCH, and "futility" at CCH. Criteria for group 2 were similar and included significant postoperative complications. Although the percentages with a do-not-resuscitate (DNR) status were comparable (SCH, 51%; CCH, 55%), the application of the DNR order differed in each SICU. The majority of neonates at SCH had either withholding or withdrawal of life support, whereas no further escalation in treatment was offered for infants with a DNR order at CCH. The average survival period after the DNR order was 4 days at SCH and 7 days at CCH. CONCLUSION: DNR orders were used for more than half the surgical neonates with critical illness. Criteria for DNR status and implementation of patient care after the DNR order differed between the SICUs.

Euthanasia, Passive↗
PubMed1995

Factors influencing whether or not couples seek genetic counselling: an explorative study in a paediatric surgical unit.

To investigate the factors influencing whether or not couples seek genetic counselling, the parents of 37 children with a major congenital anomaly were interviewed at home. All the children had been admitted to the Intensive Care Unit (ICU) of the Department of Paediatric Surgery. After physical examination of the child, the consultant clinical geneticist stated that genetic counselling was indicated for the parents. Whether they sought genetic counselling was left to the parents to decide. Eighteen of the 37 parents had sought genetic counselling. Assessment of the joint influence of a number of factors revealed that two factors were separately paramount in distinguishing between couples who did seek genetic counselling and those who did not: whether parents considered genetic counselling useful in their case shortly after the birth of their affected child, and whether the couple was clearly and correctly informed about the indication for genetic counselling. The intention to have a subsequent pregnancy was not associated with whether or not couples sought genetic counselling. Loss of information was observed: 1/3 of the referrals for genetic counselling mentioned on the written consultation forms were not stated in the discharge letters. This loss of information could have been reduced by a) routinely including the indication for genetic counselling in the discharge letter and b) appointing a coordinating physician to ensure that the parents were informed clearly about the availability of genetic counselling. Resistance to genetic counselling needs to be respected by the physician. Exploring its background might help to reduce this resistance.

Attitude to Health↗
PubMed1994

Inhibition of T3-receptor binding by Nitrofen.

Lung development is controlled by various hormones, including thyroid hormone. The herbicide 2,4-dichlorophenyl-p-nitrophenyl ether (Nitrofen) induces lung hypoplasia in fetal rats, when administered to the mother during gestation. Nitrofen might be teratogenic by an anti-thyroid activity. The present study shows that Nitrofen decreases the binding of T3 to the alpha 1 and beta 1 form of the thyroid hormone receptor in a non-competitive way. Consequently, rat lung hypoplasia might result from the decreased binding of T3 to its receptor, via exposure to Nitrofen during fetal development.

Animals↗
PubMed1994

[Limitations to care; evaluation of decision making concerning the death of 104 children in a surgical intensive care unit].

OBJECTIVE: To analyse the decision-making process concerning withholding and withdrawal of life-sustaining treatment in children who died in a paediatric surgical intensive care unit. DESIGN: Retrospective evaluation of medical and nursing records from the period 1988-1992. SETTING: Sophia Children's Hospital-University Hospital Rotterdam. METHOD: The evaluation concerned 104 children who died in the paediatric surgical intensive care unit during the study period. The causes of death were classified according to the classification proposed in a recent report issued by the Dutch Association of Paediatricians. A distinction was made between newborns and older children. RESULTS: In both newborns and older children, about half of the children had died because treatment was either withheld (4/104) or withdrawn (53/104). There were no cases of 'intentional termination of life in emergencies'. The remaining children had died in spite of medical treatment that had been considered worthwhile. CONCLUSION: The problems and guidelines suggested from the field of neonatology are applicable not only to newborns with severe congenital anomalies, but also to older children. Evaluation of the decision-making process should not be limited to medical-technical and nursing aspects, but should also include the experiences of the parents and the treatment team.

Child↗
PubMed1994

[Care and experiences of 20 set of parents concerning the death of children in a surgical intensive care unit].

OBJECTIVE: To gain insight into the attitude and experiences of parents concerning the death of children in a paediatric surgical intensive care unit of a University Children's hospital. DESIGN: Retrospective evaluation of records from 1988-1992, supplemented with semistructured interviews in the second half of 1992. SETTING: Sophia Children's Hospital-University Hospital Rotterdam. PATIENTS AND METHODS: The evaluation concerned 104 children. In 36 children death was a direct consequence of their illness, 11 died unexpectedly after an unsuccessful attempt at resuscitation, and in the remaining 57 treatment had not been initiated or had been withdrawn. Six months after the death of their child, twenty couples of parents of 20 children were asked after their experiences before, during, and after this death; in addition they were asked whether they would appreciate a longer contact with the hospital. RESULTS: Most parents chose to be present at the moment of dying. The parents generally highly appreciated the talks about the decision-making process and about coming to terms with the loss of their child, both with doctors and nurses. Most also appreciated a talk at some later time. CONCLUSION: The results from this study indicate that structured guidance of parents concerning their child's death in the form of a counselling programme, is advisable.

Adult↗
PubMed1994

Etiological aspects of congenital diaphragmatic hernia: results of a case comparison study.

We report the results of a parental questionnaire concerning possible etiological and teratological factors, such as exposure to herbicides, in the development of congenital diaphragmatic hernia (CDH). The herbicide Nitrofen interferes with lung development in rats, can induce diaphragmatic hernia and greatly resembles thyroid hormone. No association with the studied teratogens nor with maternal thyroid dysfunction was found. The questionnaire was completed by 33 parents whose baby had CDH, and by 43 couples whose baby had oesophageal atresia. The resemblance of Nitrofen to thyroid hormone, a well-known growth factor for the developing lung, is of particular interest from a pathogenetic point of view in the development of CDH.

Case-Control Studies↗
PubMed1994

Gas exchange across native lungs and extracorporeal membrane in neonates and pigs during extracorporeal membrane oxygenation.

Extracorporeal membrane oxygenation (ECMO) is a commonly used treatment modality for severe neonatal respiratory failure. The aim of the present study was to evaluate the relationship between ECMO blood flow and gas exchange across the native lungs and the extracorporeal membrane. In three healthy pigs, the ECMO flow correlated significantly with oxygen transfer (VO2) across the membrane (n = 12, r = .90, P < .001) and inversely with VO2 across the lungs (n = 12, r = -.75, p < .005). In three pigs with acute respiratory distress syndrome induced by repeated bronchoalveolar lavage, flow also significantly correlated with VO2 across the membrane (n = 9, r = .93, P < .001) and inversely with VO2 across the lungs (n = 9, r = -.97, P < .001). Eight neonates had measurements taken at different time intervals and different flow rates during ECMO. The ECMO flow correlated significantly with VO2 across the membrane (n = 45, r = .61, P < .001) and inversely with VO2 across the lungs (n = 15, r = -.54, P < .05). The relationship between carbon dioxide transfer (VCO2) and ECMO flow rates had the same trend as VO2 on all occasions. It is concluded that the ECMO flow rate is one of the main determinants of gas exchange across the lungs and the membrane.

Animals↗
PubMed1994

Evaluation of lung function changes before and after surfactant application during artificial ventilation in newborn rats with congenital diaphragmatic hernia.

Patients with congenital diaphragmatic hernia (CDH) have unilateral or bilateral hypoplasia of the lungs including delayed maturation of the terminal air sacs. Because these lungs are highly susceptible to barotrauma and oxygen toxicity, even in full-term newborns, continued research into optimal ventilatory regimen is essential to improve survival rate and to prevent ongoing lung damage. Against this background, the effect of exogenous surfactant application is evaluated. In newborn rats, CDH was induced after a single dose of 2,4 dichloro-4'-nitrophenyl (Nitrofen) (400 mg/kg) on day 10 of gestation. The newborn rats were intubated immediately after hysterotomy, transferred to a heated multichambered body plethysmograph, and artificially ventilated. Inspiratory peak pressures were initially set at 17 cm H2O, with positive end-expiratory pressure at 0 cm H2O and FIO2 at 1.0. The pressure was raised in steps of 5 cm H2O, from 5 to 30 cm H2O, to obtain pressure-volume diagrams at 0, 1, and 6 hours of artificial ventilation. These measurements were obtained in controls and in CDH rats with and without endotracheal installation of bovine surfactant (n = 4 to 10 in each group). Significant differences in lung volume between CDH and control rats were observed at all time-points. Surfactant application had a positive effect on lung volume, especially in control rats at t = 1 hour. No significant differences were observed between the CDH groups at t = 1 or t = 6 hours. In this animal model, the effect of artificial ventilation as well as the beneficial short-term effect of exogenous surfactant application have been evaluated. A continued positive effect on lung volume in CDH lungs could not be determined. Routine administration of exogenous surfactant in human CDH patients is not supported by these experimental results.

Animals↗
PubMed1994

Tracheal agenesis.

Agenesis of the trachea is a rare anomaly. The main signs are respiratory distress and cyanosis, inability to vocalize and impossible tracheal intubation. In most cases concomitant congenital anomalies of the heart, digestive tract or genitourinary tract are present. Endoscopy and X ray studies will confirm the diagnosis. There is no long-term surgical solution because no suitable material for a tracheal prosthesis is available at present, therefore the condition is ultimately fatal. We report a case of tracheal agenesis. After the diagnosis was established the baby's lungs were ventilated for several hours via an oesophageal tube and two broncho-oesophageal fistulae, but she finally died from untreatable respiratory acidosis. Autopsy revealed a Floyd's type III tracheal agenesis and a laryngeal cleft.

Acidosis, Respiratory↗
PubMed1993

Ultrastructural features of alveolar epithelial cells in the late fetal pulmonary acinus: a comparison between normal and hypoplastic lungs using a rat model of pulmonary hypoplasia and congenital diaphragmatic hernia.

The aim of this study was to describe and compare the ultrastructural features and functional maturity of alveolar epithelial cells in hypoplastic and normal fetal rat lungs. Pulmonary hypoplasia in association with congenital diaphragmatic hernia was induced in fetuses by administration of 2,4-dichlorophenyl-p-nitrophenylether (Nitrofen) to pregnant Sprague Dawley rats (100 mg on day 10 of gestation). Lung tissue of Nitrofen-exposed and control fetal rats aged 19-22 days (vaginal plug day 1, birth day 23) was embedded in Epon. Semithin (1 micron) toluidine blue-stained sections were examined by light microscopy; ultrathin sections (approximately 80 nm) were studied via transmission electron microscopy. In bronchoalveolar lavage fluid from control and Nitrofen-exposed fetuses (day 22), phospholipid fractions and surfactant protein A content were measured semiquantitatively. On day 19 both control and Nitrofen-exposed lungs contained only cuboid alveolar epithelial cells; from day 20 there were cuboid, low cuboid, and thinner epithelial cells. The (low) cuboid cells contained large glycogen fields, some precursory stages of multilamellar bodies (MLBs), and just a few mature MLBs on day 19 and 20; smaller glycogen fields, more precursory stages, and more mature MLBs on day 21; and little or no glycogen but many precursory stages and mature MLBs on day 22. The thinner cells contained little or no glycogen and a few precursory stages of MLBs on days 20-22; very thin cells on day 22 contained neither glycogen nor any precursory stages of MLBs. MLBs and tubular myelin were seen in the lumens of future air spaces from day 20 onward. Nitrofen-exposed lungs differed from control lungs in that inclusion bodies (IBs) were less numerous in (low) cuboid alveolar cells on days 19 and 20, and more glycogen was seen on day 22. In addition intra- and extracellular "MLBs" in exposed lungs more often had an unusual appearance, i.e., a confluent structure and higher electron density. However, despite morphologic differences, there was no clear difference in phospholipid composition and SP-A content per mol phospholipid in bronchoalveolar lavage fluid. We conclude that morphologically hypoplastic lungs are less mature near term, without an apparent effect on surfactant composition.

Animals↗