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M Sinaasappel

Publications and source records attributed to M Sinaasappel.

At least 37 records · Page 2Linked to original sources
PubMed1997

Low-dose versus high-dose ursodeoxycholic acid in cystic fibrosis-related cholestatic liver disease. Results of a randomized study with 1-year follow-up.

BACKGROUND: Ursodeoxycholic acid (UDCA) is beneficial in cholestasis related to cystic fibrosis (CF). High-dose treatment has been recommended to compensate for bile salt malabsorption. We compared the results of low-dose (10 mg/kg/day) and high-dose (20 mg/kg/day) UDCA treatment on liver biochemistry after 3 and 12 months' treatment. METHODS: Thirty CF patients (age > 5 years) with biochemical cholestasis and compensated liver disease were randomized for low-dose (n = 17) or high-dose (n = 13) UDCA. Baseline clinical variables were comparable. RESULTS: After 1 year one patient had died of liver failure (low dose), and three had dropped out because of pruritus (one in each group) or personal choice (low dose). In the high-dose group improvement in gamma-glutamyl transferase values was more pronounced after 3 months and 1 year (P < 0.004), and improvement of alanine aminotransferase was better after 1 yer (P < 0.02). Improvement of alkaline phosphatase and aspartate aminotransferase was comparable. Complete normalization of liver enzymes and bilirubin occurred more often in the high-dose group. CONCLUSION: High-dose UDCA induces a better response of liver biochemistry values than low-dose UDCA in CF patients with cholestatic liver disease.

Adolescent↗
PubMed1997

Blocking of alpha 1 beta 1 integrin strongly improves survival of hepatocytes in allogeneic transplantation.

The survival rate of hepatocytes after allogeneic hepatocyte transplatation (HTX) is low, possibly because of formation of intravascular hepatocyte aggregates. The aim of this study was to determine the role of integrins in intravascular aggregation and intraparenchymal survival of transplanted hepatocytes in a fully allogeneic rat model. First, the expression profile of various integrins was determined on both isolated hepatocytes in vitro and on hepatocyte aggregates in recipient livers after intraportal transplantation of allogeneic hepatocytes. Next, the role of these integrins in hepatocyte aggregation was determined in an in vitro attachment assay on liver sections with function-blocking anti-integrin monoclonal antibodies (mAb). The results showed that anti-alpha 1 beta 1 integrin mAb significantly block hepatocyte attachment to vessel walls and liver parenchyma in vitro. Subsequently, the effect of preincubation of hepatocytes with anti-integrin mAb on their intravascular aggregation and on intraparenchymal survival was studied in an allogeneic HTX model. Preincubation with anti-leukocyte function-associated antigen-1 alpha or anti-beta 2 mAb significantly intravascular hepatocyte aggregation, and anti-leukocyte function-associated antigen-1 alpha mAb enhanced intraparenchymal survival. Preincubation with anti-alpha 1 or anti-beta 1 mAb did not inhibit aggregation but significantly improved survival from 2% to up to 45% at Day 2 after transplantation (p < 0.001). In conclusion, our results suggest that the blocking of alpha 1 beta 1 integrin significantly improves survival of allotransplanted hepatocytes.

Animals↗
PubMed1996

Correction of an inborn error of metabolism by intraportal hepatocyte transplantation in a dog model.

The aims of this study were (1) to assess portal hemodynamics during intraportal hepatocyte transplantation (HTX) in dogs, (2) to evaluate a new method for the detection of transplanted hepatocytes using 5-bromo-2'-deoxyuridine (BrdU) incorporation, and (3) to determine the metabolic effects of HTX on an inborn error of the purine metabolism in dalmatian dogs. HTX was performed by intraportal infusion of freshly isolated allogeneic beagle hepatocytes. Portal flow and pressure were monitored continuously during HTX. For the detection experiments, beagles received hepatocytes that had been exposed to BrdU during regeneration of the donor liver, induced by partial hepatectomy. For metabolic studies, dalmatian dogs were used as recipients. Repetitive HTX was performed. As judged by the portal hemodynamics, the number of hepatocytes that could be infused safely varied from 5 x 1O(8) to 8 x 1O(8) in beagles, to 1 x 10(9) in dalmatians. Transaminase levels showed a 5- to 6-fold increase (P=0.05) after HTX, but normalized within 3 weeks. BrdU-positive cells were identified in the recipient livers 2 weeks after HTX and 5-10% of the total amount of transplanted hepatocytes was retrieved. A significant (P=0.05) decrease in serum uric acid was demonstrated after repeated HTX in dalmatians. In conclusion, (1) intraportal HTX is feasible, but portal hypertension limits the maximum amount of hepatocytes that can be infused in one HTX; (2) BrdU labeling is an attractive method for the detection of transplanted hepatocytes in the recipient liver; and (3) after two consecutive hepatocyte transplantations, a temporary correction of the purine metabolism was accomplished in the dalmatian dog.

Animals↗
PubMed1996

Current therapy for Crigler-Najjar syndrome type 1: report of a world registry.

This study represents a multicenter survey on the management of patients with Crigler-Najjar syndrome (CNS) type 1. The aim of the survey was to find guiding principles for physicians in the care of these patients. Fifty-seven patients were included. At the time of inclusion, 21 patients had received a liver transplant (37%). The average age at transplantation was 9.1 +/- 6.9 years (range, 1-23 years); the age of the patients who had not been transplanted at the time of inclusion was 6.9 +/- 6.0 years (range, 0-23 years). Brain damage had developed in 15 patients (26%). Five patients died, and 10 are alive with some degree of mental or physical handicap. In 2 patients, ages 22 and 23 years, early signs of bilirubin encephalopathy could be reversed, in 1 by prompt medical intervention followed by liver transplantation and in the other by prompt liver transplantation. Seven patients underwent transplantation with some degree of brain damage at the time of the surgery; 1 of these died after retransplantation, 2 improved neurologically, and 4 remained neurologically impaired. The age of 8 patients with and 13 without brain damage at or before transplantation was 14.3 +/- 5.9 and 5.9 +/- 5.4 years (P < .01), respectively. Therapy of CNS type 1 consists of phototherapy (12 h/d), followed by liver transplantation. Phototherapy, although initially very effective, is socially inconvenient and becomes less efficient in the older age group, thus also decreasing compliance. Currently, liver transplantation is the only effective therapy. This survey shows that, in a significant number of patients, liver transplantation is performed after some form of brain damage has already occurred. From this, one must conclude that liver transplantation should be performed at a young age, particularly in situations in which reliable administration of phototherapy cannot be guaranteed.

Adolescent↗
PubMed1996

Calibration of Pd-porphyrin phosphorescence for oxygen concentration measurements in vivo.

Quantitative measurement of oxygen concentrations in the microvasculature is of prime importance in issues related to oxygen transport to tissue. The introduction of the quenching of the Pd-porphyrin phosphorescence as oxygen sensor in vivo by Wilson et al. (J. Appl. Physiol. 74: 580-589, 1993) has provided in this context a major advance in this area of research. For in vivo application, the dye is coupled to albumin to restrict the dye to the circulation and to measure oxygen in the physiological range. In this study a phosphorimeter with a gated photomultiplier is presented and validated. Furthermore, a nonlinear-fit method using the Marquardt-Levenberg algorithm is used to calculate the decay time. With this new phosphorimeter, calibration measurements were performed to investigate the effects of pH, temperature, and diffusivity. The results present a preparation method for albumin coupling of the dye that eliminates the pH dependency of the quenching kinetics. Furthermore, the decreased oxygen diffusivity of serum was compared with that of water, and it was shown that calibration constants measured in water can be extrapolated to serum.

Algorithms↗
PubMed1996

In vivo measurement of chloride and water secretion in the jejunum of cystic fibrosis patients.

In the present study, we have investigated the possible consequences of the chloride channel defect in the intestine of cystic fibrosis (CF) patients for electrolyte and water transport in the jejunum in vivo, using a multilumen, double occluding balloon catheter, and an Ag/AgCl intraluminal electrode. During a chloride-free perfusion, to optimize the sensitivity of our measurements, the transmural potential difference (PD) (lumen with reference to serosal side) was found to be significantly higher in the jejunum of CF patients (+8.0 +/- 2.1 mV; n = 5) than in healthy control subjects (-2.2 +/- 2.0 mV; n = 9). The chloride concentration measured in chloride-free jejunal perfusates of CF patients was significantly lower than in controls (10.9 +/- 2.3 and 41.4 +/- 8.2 mM, respectively). Possible differences in net chloride and water secretion did not reach statistical significance (chloride secretion controls: -2.1 +/- 0.9 mmol/10 cm/h; CF: -0.8 +/- 0.2 mmol/10 cm/h; water secretion controls: -0.8 +/- 2.5 mL/10 cm/h; CF: -11.7 +/- 8.9 mL/10 cm/h). In control subjects, intraluminally applied theophylline stimulated the secretion of water (delta 23.4 +/- 4.6 mL/10 cm/h) and chloride (delta 4.1 +/- 1.1 mmol/10 cm/h), but not in CF patients (respectively delta 3.6 +/- 3.3 mL/10 cm/h and delta 1.1 +/- 1.1 mmol/10 cm/h). In controls, theophylline caused a significant increase in lumen negativity (PD -10.2 +/- 2.6 mV), but no change could be seen in CF patient transmural PD. These observations provide in vivo evidence for a decreased chloride permeability in the jejunum in CF, resulting in a significant reduction in net electrolyte and water secretion in the presence, but not in the absence, of an intestinal secretagogue.

Adolescent↗
PubMed1995

Gastroesophageal reflux and ENT disorders in childhood.

Among controversies in pediatric otorhinolaryngology, the role of gastroesophageal reflux (GER) in inflammatory disorders of the upper airway remains of major concern. A laryngeal involvement by GER was demonstrated in adults and a correlation with GER has been found in pediatric populations with recurrent croup. However, although considered statistically significant, these results concern a few patients only and are inconclusive for a causal relationship. In addition, pH monitoring, often considered as the gold standard for the diagnosis of GER disease, has failed in giving normal values in ENT disorders. Eventually, upper pharyngeal and nasal involvements by GER and GER-related otitis media or otalgia have been suggested by some authors. In the 6th International Congress on Pediatric Otolaryngology, the Symposium on GER was designed to help physicians in improving their knowledge of the data from the literature and their understanding of the involved mechanisms. Bearing in mind the potential severity of GER disease, the audience also heard and debated the most up-to-date methods of assessing GER and treating it in patients with possibly related otorhinolaryngological symptoms. Here is the summary of this symposium.

Child↗
PubMed1995

Present and future treatment modalities for gastrointestinal diseases in cystic fibrosis.

In recent years knowledge of the basic defect of CF has increased enormously. Many new drugs and treatment strategies are being introduced in the clinic. Nevertheless, there are a number of unsolved problems in the treatment of malabsorption and malnutrition. In spite of innovative technical and pharmacological improvement of pancreatic enzyme preparations maldigestion is still a problem. Better enzymes and coatings are needed. The integrated action of enzymatic digestion, intestinal motility and absorption is not under control. The role of malnutrition in the development of complications and in the outcome of the disease is still under discussion. The importance of a high energy intake is now generally accepted, but the question is how to achieve this. Tube feeding, endoscopic gastrostomy and the use of diets with a high energy content are becoming more popular. In CF the relationship between gastro-oesophageal reflux and lung complications is not well understood, but GER is frequently recognized. In the absence of CF GER is also associated with a number of pulmonary and upper airway diseases. The incidence of liver fibrosis and cholestatic liver disease is increasing with age. The problem is how to identify the patients at risk. The use of choleretic drugs has shown promising results in preliminary studies. Gene therapy in pancreatic and gastrointestinal pathology will be restricted to the liver. The biliary tract could be an interesting target, if patients at risk can be identified. In conclusion, new drugs and new strategies are necessary for the future implementation of the results of new insights in CF.

Cystic Fibrosis↗
PubMed1994

Proliferative response of hepatocytes transplanted into spleen or solid support.

Understanding the regenerative behavior of transplanted hepatocytes is of great importance for developing and improving such novel therapeutic strategies as hepatocellular transplantation and ex vivo gene therapy. In this study the proliferative responsiveness of transplanted syngeneic rat hepatocytes was examined in relation to the timing of the administration of a mitogenic stimulus. For this purpose nuclear bromodeoxyuridine incorporation after partial hepatectomy was investigated during the early post-transplant phase. The response of intrasplenically transplanted hepatocytes was compared to that of liver cells engrafted in polytetrafluoroethylene solid supports that had been implanted intraperitoneally 4 weeks prior to transplantation. Nonstimulated, engrafted hepatocytes exhibited a labeling index of approximately 0-1% independent of the transplantation technique used. This "spontaneous" labeling index did not change with time. Partial hepatectomy, executed simultaneously with hepatocyte transplantation through either technique, did not result in significant alteration of this proliferation index. Delayed kinetics were found not to be responsible for this lack of responsiveness. When the mitogenic stimulus was given between 2 and 6 weeks post-transplantation, a significant increase in labeling index was observed in comparison to sham-treated control animals. Maximal labeling indices of approximately 3-4% were found if the stimulus took place at 4 weeks post-transplantation. Both the pattern and the extent of the proliferative response seen in liver cells engrafted in solid supports were similar to the ones found in intrasplenic hepatocytes, indicating adequate vascularization of the supports. This data provides the first description of proliferative response in hepatocytes transplanted by the solid support technique, which may offer an attractive alternative to the intrasplenic route.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Determinants of mild clinical symptoms in cystic fibrosis patients. Residual chloride secretion measured in rectal biopsies in relation to the genotype.

Previous Ussing chamber measurements of secretagogue-provoked changes in short circuit current in rectal suction biopsies of cystic fibrosis (CF) patients showed that in a minority of patients chloride secretion in response to cholinergic agonists is reduced but not completely absent. To assess a possible relationship between this phenomenon and both the genotype and the phenotype, we performed Ussing chamber experiments on rectal suction biopsies of 51 CF patients. The CF mutation was identified in 89 out of 102 CF alleles. No apparent chloride secretion was found in 30 CF patients (group I). Low residual chloride secretion was found in 11 CF patients (group II), while a relatively high residual secretion appeared in 10 CF patients (group III). Pancreatic function was preserved more frequently in CF patients displaying residual secretion: 0% in group I, 27% in group II, and 60% in group III (P < 0.001). The age at diagnosis (mean +/- SEM) in group III (18.4 +/- 6.6) was significantly different from group I (1.2 +/- 0.4, P < 0.01) and group II (3.5 +/- 1.4, P = 0.05). Residual chloride secretion was found in some of the 28 dF508 homozygous patients (three in group II, and one in group III), disclosing that other factors than the CF gene defect itself affect the transepithelial chloride transport. The age at diagnosis correlates significantly with the magnitude of the secretory response, even within the dF508 homozygous patients (r = 0.4, P < 0.05). We conclude that residual chloride secretion in CF is the pathophysiological basis of preserved pancreatic function and delayed presentation of the disease, which is not exclusively determined by the CF genotype.

Adolescent↗
PubMed1993

[Hepatitis B in children in 4 university centers in The Netherlands].

OBJECTIVE: To evaluate the prevalence and the natural course of hepatitis B infection in children. DESIGN: Retrospective longitudinal. SETTING: Four university pediatric centres. METHOD: To explore the possibility of starting a trial with interferon alpha, data of viral and biochemical tests and biopsies of children younger than 16 years were studied. RESULTS: In a period of 10 years (1980-1990) 145 patients, of whom 74% were not of original Dutch descent, were found positive for HBsAg. The data of 142 patients could be analysed. Seroconversion was seen in 27 patients and 42 were already anti-HBe positive at the time of presentation. Chronic hepatitis, representing the category which could benefit from interferon alpha treatment, was found in 24 patients. Severe complications of the hepatitis were found in 4% of the children, including hepatocellular carcinoma and cirrhosis. Follow-up was insufficient so the seroconversion rate could only be estimated at 12% for the first year following the diagnosis. CONCLUSION: As a result of this study the authors present a proposal for a therapeutic trial with interferon alpha. This is a national protocol under the auspices of the section for pediatric gastroenterology of the Nederlandse Vereniging voor Kindergeneeskunde (Netherlands Pediatric Association).

Adolescent↗
PubMed1993

A mutation in bilirubin uridine 5'-diphosphate-glucuronosyltransferase isoform 1 causing Crigler-Najjar syndrome type II.

BACKGROUND: Inherited unconjugated hyperbilirubinemia in Crigler-Najjar type II (CN II) is caused by a strong reduction of bilirubin uridine 5'-diphosphate-glucuronosyltransferase (B-UGT) activity. Both B-UGT isoenzymes (B-UGT1 and B-UGT2) identified in humans are derived from a single gene by alternative splicing. To clarify the genetic background of CN II and the role of both B-UGT forms in the physiological clearance of bilirubin, we have studied a large kindred with two CN II patients. METHODS: From genomic DNA all B-UGT encoding exons were amplified by polymerase chain reaction and sequenced to identify mutations causing CN II. RESULTS: The CN II patients were found to be homozygous for a nucleotide shift in the unique region of B-UGT1, changing a arginine into a tryptophan, and also for a nucleotide shift in the unique region of B-UGT2, changing a leucine into a valine. Analysis of other family members and of 50 control subjects showed that the mutation in B-UGT1 causes CN II, whereas the mutation in B-UGT2 is a polymorphism. CONCLUSIONS: CN II syndrome appears to be caused by a homozygous mutation in B-UGT1. This indicates that B-UGT1 is the physiological important bilirubin glucuronidating isoform.

Adult↗