J C Molenaar

Erasmus Universiteit Rotterdam, Rotterdam, South Holland, Netherlands

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Publications (164)466.52 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: In gastroschisis the protruding bowel is generally covered by a fibrous coating as a result of prolonged exposure to amniotic fluid but no such coating is found on the exposed bowel loops in a ruptured omphalocele. In patients with gastroschisis, the postoperative course is often complicated by periods of hypoperistalsis. Based on studies of animal models of gastroschisis, various authors have suggested that the postoperative complications might be due to structural defects of the bowel wall. In our own experimental investigation of gastroschisis using chick embryos, we found no evidence of a structural defect of the bowel wall. With a view to clinical substantiation of our experimental findings, we conducted a comparative investigation of patient material, involving 10 cases of gastroschisis, 5 cases of ruptured omphalocele, and 9 cases of intact omphalocele. The investigation revealed an entirely normal structure of the bowel wall in all 10 cases of gastroschisis. On the serosa we noted an inflammation infiltrate rich in collagen fibers, frequently containing squamous cells (vernix) and lanugo. In the cases of ruptured omphalocele, the bowel wall specimens revealed a subacute inflammatory reaction. No major abnormalities were found in the bowel wall of patients with an intact omphalocele. Normal development of the autonomic nervous system was found in all patient material. Severe ischemic changes of the bowel wall were found in 4 of the gastroschisis cases and these were the 4 patients who suffered from postoperative hypoperistalsis. Thus the complications occurring during the post-opertive phase of gastroschisis are most probably due to ischemic bowel damage.
    Fetal & Pediatric Pathology. 02/2011; 7(3).
  • Archives of Sexual Behavior 03/2000; 29(1):119-21. · 3.53 Impact Factor
  • Archives of Sexual Behavior 01/2000; 29(1):119-121. · 3.53 Impact Factor
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    ABSTRACT: Auxiliary liver transplantation is an attractive alternative for orthotopic liver transplantation in patients with certain inborn errors of metabolism of the liver in which complete resection of the liver is unnecessary or even contraindicated. Because in these diseases portal hypertension is mostly absent, finding a balance in portal blood distribution between native liver and graft is complicated. The objective of this study was to investigate requirements for long-term (180 days) graft survival in auxiliary partial heterotopic liver transplantation (APHLT) in a dog model. A metabolic defect was corrected in 26 dalmation dogs with a 60% beagle heterotopic auxiliary liver graft. Four groups of different portal inflow were studied. In the ligation group the portal vein to the host liver was ligated. In the split-flow group graft and host liver received separate portal inflow. In the banding group the distribution of the portal flow was regulated with an adjustable strapband and in the free-flow group the portal blood was allowed to flow randomly to host or graft liver. Metabolic correction increased in all groups after transplantation from 0.19 +/- 0.02 to 0.70 +/- 0.05 (P< .0001) but remained significantly better in the ligation and split-flow groups (graft survival, 135 +/- 27 and 144 +/- 31 days). In the banding group metabolic correction decreased significantly after 70 days, and although the grafts kept some function for 155 +/- 14 days, in 4 of 6 dogs portal thrombosis was found. In the free-flow group, competition for the portal blood led to reduced correction within 12 days and total loss of function in 96 +/- 14 days. Graft function also was assessed with technetium (Tc) 99m dimethyl-iminodiacetic acid uptake. A good linear association between HIDA uptake and metabolic correction was observed (r = 0.74; P < .0005). Grafts that contributed more than 15% to the total uptake of HIDA showed biochemical correction. This indicates a critical graft mass of about 15% to 20% of the hepatocyte volume to correct this metabolic defect. Auxiliary partial heterotopic liver transplantation can be a valuable alternative treatment for inborn errors of hepatic metabolism if the native liver and the graft receive separate portal blood inflow.
    Journal of Pediatric Surgery 08/1999; 34(8):1265-8. · 1.38 Impact Factor
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    ABSTRACT: Treatment of psychological problems of 59 children with a physical intersex condition is described. The group consisted of 18 female pseudohermaphrodites with congenital adrenal hyperplasia (CAH), 20 male pseudohermaphrodites and 2 true hermaphrodites born with ambiguous external genitalia assigned the female sex (ambiguous girls), 14 male pseudohermaphrodites born with completely female external genitalia and assigned the female sex (completely female group), and 5 male pseudohermaphrodites born with ambiguous external genitalia and assigned the male sex. Despite the sex assignment, genital organ correction soon after birth, psychological counseling of parents and intensive psychotherapy of the children, general psychopathology developed equally in all 4 groups (39% of total group). Although 87% of the girls with a physical intersex condition developed in line with the assigned sex, 13% developed a gender identity disorder though only 1 girl (2%) failed to accept the assigned sex. Gender identity disorder and deviant gender role were in evidence only in girls with CAH and girls of the ambiguous group. Biological and social factors seem responsible for the development of gender identity disorder, such as pre- and postnatal hormonal influences on the brain enabling deviant gender role behavior to develop, and an inability on the part of parents to accept the sex assignment. A reconsideration of the sex assignment in male pseudohermaphrodites and true hermaphrodites born with ambiguous external genitalia is discussed.
    Archives of Sexual Behavior 05/1998; 27(2):125-44. · 3.53 Impact Factor
  • Source
    J H Bergmeijer, J S Harbers, J C Molenaar
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    ABSTRACT: We analyzed the very long-term results of the Nissen-Rossetti fundoplication performed in young children. Little has been reported about follow-up longer than 5 years in homogeneous populations. This study concerns a homogeneous group with a minimum follow-up of 10 years; these former patients, therefore, are now adolescents or adults. In 24 consecutive patients without other congenital or acquired anomalies of the esophagus or stomach, we evaluated the primary postoperative diagnoses, symptoms of recurrent reflux, and their state of health in 1994. After a median follow-up of 16 years, the result was excellent in 18 patients, good in 5, and poor in I (graded according to Visick). Patients with recurring reflux symptoms had evidence of failure of the fundoplication. All but 1 had been given a diagnosis of recurrent reflux within 2 years after the operation. The situation after 2 years seems predictive for the later outcome. In almost all cases, the Nissen-Rossetti fundoplication is a long-lasting, effective treatment for young children with symptomatic gastroesophageal reflux.
    Journal of the American College of Surgeons 04/1997; 184(3):259-61. · 4.50 Impact Factor
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    ABSTRACT: Neonates with congenital diaphragmatic hernia (CDH) often suffer from respiratory insufficiency due to lung hypoplasia and pulmonary hypertension. Artificial ventilation is frequently required, and this leads to a high incidence of bronchopulmonary dysplasia. Long-term follow-up studies have shown persisting airway obstruction. To evaluate the long-term pulmonary sequelae in CDH, we studied 40 CDH patients of age 7 to 18 yr (median 11.7 yr) and 65 age-matched controls without CDH and lung hypoplasia who underwent similar neonatal treatment. Mild airway obstruction was found in both groups with more peripheral airway obstruction in CDH patients than in control subjects. Both groups had normal TLC and single-breath carbon monoxide diffusion capacity (DLCO). CDH patients had increased residual volume (RV) and RV/TLC compared with controls. Increased airway responsiveness to methacholine (MCH) was common but bronchoconstriction to inhaled metabisulfite (MBS) was rare both in CDH and control subjects. We conclude that this group of CDH patients has minor residual lung function impairment. Mild airway obstruction and increased airway responsiveness to inhaled MCH but not to MBS suggest that structural changes in distal airways are involved and not autonomic nerve dysfunction. Both artificial ventilation in the neonatal period and residual lung hypoplasia seem important determinants of persistent lung function abnormalities in CDH patients.
    American Journal of Respiratory and Critical Care Medicine 02/1997; 155(1):174-80. · 11.04 Impact Factor
  • Clinical Nutrition - CLIN NUTR. 01/1997; 16:51-51.
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    ABSTRACT: This study was conducted to gain insight into the attitudes of medical staff towards life-support of newborns with life-threatening problems, seen against the background of these children's expected morbidity and quality of life. The opinions about the mode of life-support were determined by questionnaires and the demographic characteristics of the respondents were noted. Each patient's risk of mortality was scored by means of the standardized Paediatric Risk of Mortality Score (PRISM). Attitudes towards support were unanimous for 39 of the 46 patients. For the other 7 patients at least one of the respondents preferred a different support mode than that given at the time. The attitudes were influenced by the patient's risk of mortality. Conclusion: Decisions about life-support of newborns with life-threatening problems should include all the disciplines involved in patient care and should be made at an early stage.
    European Journal of Pediatrics 10/1996; 155(9):783-6. · 1.91 Impact Factor
  • Intensive Care Medicine 06/1996; 22(2). · 5.26 Impact Factor
  • Intensive Care Medicine 06/1996; 22(2). · 5.26 Impact Factor
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    ABSTRACT: Short bowel syndrome (SBS) in the newborn results in limited intestinal absorptive capacity, leading especially to fatty acid (FA) malabsorption. It is unknown whether adaptation occurs in time in FA absorption, and whether this adaptation is chain-length dependent. The aid of the present study was to prospectively evaluate FA absorption and excretion during SBS in the newborn. Twenty-one neonates who underwent small bowel resection (of variable length) for various reasons (necrotizing enterocolitis, intestinal atresia, meconium peritonitis, cloacal extrophy, etc) were studied. Eight neonates had SBS, defined as a small bowel remnant of less than 50% of the original small bowel length related to gestational age. The mean remaining small bowel length in the SBS group was 34% (24% to 42%). The non-SBS control group consisted of 13 neonates who had only minor small bowel resections. The mean remaining bowel length for the non-SBS group was 95% (70% to 100%). The results show that the total fractional excretion of FA (FE-FA) at 2 weeks and 1, 2, 3, and 4 months postsurgery was 51% +/- 37%, 33% +/- 24%, 51% +/- 65%, 53% +/- 27%, and 7% +/- 2% in patients with SBS, versus 12% +/- 8%, 24% +/- 10%, 9% +/- 3%, 8% +/- 3% and 17% +/- 14% in the non-SBS controls, respectively (P < .05 by ANOVA). There appeared to be an amelioration in time in FA absorption, especially in the SBS group, after 3 months. FE-FA was chain-length related, being considerably less for C10 and C12 than for C14 and longer amounts. An amelioration of absorption occurred in the SBS patients, especially with the longer-chain FA. On the basis of the study data, the authors conclude that in the initial adaptation phase shorter chain lengths are better absorbed than longer chain lengths; however, in the latter FA group, substantial adaptation occurs with time.
    Journal of Pediatric Surgery 05/1996; 31(4):520-5. · 1.38 Impact Factor
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    ABSTRACT: 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.
    Journal of Pediatric Surgery 09/1995; 30(8):1127-30. · 1.38 Impact Factor
  • G Liefaard, E Heineman, J C Molenaar, D Tibboel
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    ABSTRACT: 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)
    Journal of Pediatric Surgery 04/1995; 30(3):388-91. · 1.38 Impact Factor
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    ABSTRACT: This study was undertaken to investigate whether two-stage segmental small bowel allotransplantation can maintain growth and development of young dogs (16 weeks, 5 to 6 kg) with surgically created short bowel syndrome (SBS). After near-total small bowel resection (group 1; n = 3), irreversible weight loss was noted. After a sham operation (group 2; n = 3), no growth disturbances were found. Major histocompatibility matched small bowel transplantation (SBT) with cyclosporine A as immunosuppressant, was performed in two stages (group 3; n = 7). During the first stage, one meter of jejunoileum from an adult donor was placed as a Roux loop. Four weeks later, the native small bowel was removed and replaced by the graft. Only one dog survived long-term; the dogs died from infectious complications. The addition of selective decontamination of the digestive tract and early gastrostomy feeding (group 4; n = 10) resulted in long-term survival in 60%. Follow-up at 4 months showed that their growth was about 20% compromised compared with that of the sham-operated animals. Functional analysis showed that electrolytes, urea, and D-xylose were normal, but there was an increase in the lactulose:mannitol ratio, fecal fat excretion, and postheparin diamine oxidase release. These results show that under the conditions described, segmental SBT functions sufficiently to treat SBS but does not maintain normal growth.
    Journal of Pediatric Surgery 04/1995; 30(3):396-401. · 1.38 Impact Factor
  • Transplantation 10/1994; 58(5):623-5. · 3.78 Impact Factor
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    ABSTRACT: 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.
    Journal of Pediatric Surgery 08/1994; 29(8):1016-9. · 1.38 Impact Factor
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    ABSTRACT: 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.
    Journal of Pediatric Surgery 07/1994; 29(6):820-4. · 1.38 Impact Factor
  • D Tibboel, M Mourik, F W Hazebroek, J C Molenaar
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    ABSTRACT: 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. Retrospective evaluation of medical and nursing records from the period 1988-1992. Sophia Children's Hospital-University Hospital Rotterdam. 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. 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. 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.
    Nederlands tijdschrift voor geneeskunde 06/1994; 138(19):953-8.
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    ABSTRACT: 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. Retrospective evaluation of records from 1988-1992, supplemented with semistructured interviews in the second half of 1992. Sophia Children's Hospital-University Hospital Rotterdam. 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. 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. 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.
    Nederlands tijdschrift voor geneeskunde 06/1994; 138(19):958-63.

Publication Stats

2k Citations
466.52 Total Impact Points

Institutions

  • 1983–2011
    • Erasmus Universiteit Rotterdam
      • Department of Pediatric Surgery
      Rotterdam, South Holland, Netherlands
  • 1999
    • Erasmus MC
      • Department of Surgery
      Rotterdam, South Holland, Netherlands
  • 1988–1996
    • Het Oogziekenhuis Rotterdam
      Rotterdam, South Holland, Netherlands