PubMed Health⌕ Search

Biomedical subjects

N M Bax

Publications and source records attributed to N M Bax.

At least 19 recordsLinked to original sources
PubMed2006

Carbon dioxide differentially affects the cytokine release of macrophage subpopulations exclusively via alteration of extracellular pH.

BACKGROUND: The improved outcome after endoscopic surgery has been attributed to less surgical trauma. However, the underlying mechanisms are not fully understood, and direct effects of CO2 used for pneumoperitoneum, cellular acidification, and/or the lack of air contamination have been postulated to additionally modulate immune functions during endoscopic surgery. We investigated the effects of CO2 incubation, extracellular acidification, and air contamination on the inflammatory response of two distinct macrophage populations. METHODS: R2 and NR 8383 rat macrophage cell lines were used. Interleukin-6 (IL-6) and nitric oxide after lipopolysaccharide (LPS) stimulation were determined in these sets of experiments: incubation in 100% CO2, 5% CO2, and room air for 2h; incubation at pH 7.4, 6.5, and 5.5 for 2 h in 5% CO2; and incubation in 100% CO2, 5% CO2 and room air in fixed pH 6.3. The extracellular pH was monitored during incubation. We determined the alteration of intracellular pH in cells subjected to extracellular acidification by fluorescence microscopy. RESULTS: Extracellular pH decreased to 6.3 during 100% CO2 incubation. IL-6 release was reduced after CO2 incubation in NR 8383 cells and increased in R2 cells (p < 0.05). It was not altered by air incubation. Decreasing the extracellular pH to 6.5 mimicked the effects of CO2 and a decrease to 5.5 suppressed IL-6 release in both cell lines. In fixed pH at 6.3, CO2 and air incubation had no effect. CO2 and pH had no impact on nitric oxide release and vitality. Intracellular pH decreased with extracellular acidification without significant difference between the two cell lines. CONCLUSIONS: A decrease in extracellular pH during incubation in CO2 differentially affects IL-6 release in macrophage subpopulations. This may explain contradictory results in the literature. Moreover, we demonstrated that air contamination does not affect macrophage cytokine release. The decrease in extracellular pH is the primary underlying mechanism of the alteration of macrophage cytokine release after CO2 incubation, and it appears that the ability to maintain intracellular pH is not determined by the effects of CO2 or extracellular acidification.

Animals↗
PubMed2003

[Hypertrophic pyloric stenosis in infants: laparoscopic pyloromyotomy].

OBJECTIVE: To evaluate the results of laparoscopic pyloromyotomy in infants with hypertrophic pyloric stenosis (HPS). DESIGN: Retrospective. METHOD: Data from medical records were collected on all children who underwent laparoscopic extramucosal pyloromyotomy for hypertrophic pyloric stenosis in the period from 1 October 1993 to 31 March 2001 in the Wilhelmina Children's Hospital of the Utrecht University Medical Centre, the Netherlands. RESULTS: A total of 133 children were operated: 108 boys (81%) and 25 girls (19%). The mean age on the day of operation was 35.3 days (SD: 15.4). Of these children, 17 (13%) were ex-prematures and 8 (6%) were ex-dysmatures, and 40 (30%) had a positive family history for HPS. The mean operating time was 29 min (SD: 10); per surgeon, the first 5 operations required over 30 minutes on average and the following operations lasted an average of 26 minutes. Postoperatively, 84 patients (63%) no longer vomited. Four children required a second operation. The mean period from operation to discharge was 61.6 hours (SD: 46.0). Complications included: perforations of the mucosa (n = 4; 3%), wound infections (n = 4; 3%) and small incisional hernias (n = 5; 4%). CONCLUSION: Laparoscopic pyloromyotomy is an efficient and safe operative technique for the treatment of infants with HPS.

Female↗
PubMed2001

The role of laparoscopy in the management of childhood intussusception.

BACKGROUND: Some authors have argued that intussusception is best treated via a laparoscopic approach. As we did not have this impression, we reviewed our experience with this condition. METHODS: : We reviewed all patients with intussusception who were treated at our hospital over the past 10 years. The choice of whether to use a laparoscopic or open approach depended on the patient's clinical condition and the availability of surgeons with laparoscopic expertise. RESULTS: A total of 72 patients were identified. Based on age, two subgroups were distinguished-one comprised of patients under the age of 3 years and one of patients over the age of 3 years. Sixty-five patients were under 3 years of age. Thirty-five had surgery, and 19 required resection. Of the 10 patients who were treated with a laparoscopic approach, only three could be reduced laparoscopically. After conversion in the other seven patients, the intussusception was reduced in five whereas a resection was required in two cases. Seven patients were 3 years of age or older. All of them underwent surgery, and all but one required resection. All four children who were laparoscoped subsequently had a bowel resection at open surgery. CONCLUSIONS: Patients 3 years of age or older usually need resection and will not benefit from the laparoscopic approach. Under 3 years of age, little is to be gained from a laparoscopic approach, provided good nonsurgical reduction facilities are available. There is a place for the laparoscopic approach in cases of recurrent intussusception or doubtful reduction.

Age Factors↗
PubMed2001

The effect of rectosigmoidectomy and Duhamel-type pull-through procedure on lower urinary tract function in children with Hirschsprung's disease.

BACKGROUND/PURPOSE: The aim of this study was to investigate the effect of rectosigmoidectomy and Duhamel-type pull-through procedure on lower urinary tract function in children with Hirschsprungs disease. METHODS: During a 3-year period the authors assessed 11 consecutive children with Hirschsprung's disease prospectively by standard urodynamic investigations, before and after surgery. Urodynamics included simultaneous measurement of abdominal pressure, bladder pressure, detrusor pressure, and pelvic floor electromyography during filling and voiding. All children were submitted to laparoscopic resection of the aganglionic bowel segment below the cul de sac and a Duhamel-type pull-through procedure. Postoperatively, the children were assessed urodynamically and evaluated every 3 months for urologic problems. RESULTS: Mean age at first urodynamic study was 5 months (range, 2 to 10). Postoperative urodynamics were performed at a mean age of 10 months (range, 5 to 159). The mean interval between operation and postoperative urodynamic study was 6 months (range, 2 to 10). No child had structural urologic anomalies or urologic problems before surgery, and all had normal preoperative urodynamic findings. After surgery, urodynamics were considered normal in 3 children. In 7 children cystometric bladder capacity (CBC) was abnormally large, and 6 of these children had significant residuals. However, all had detrusor contractility and were able to void spontaneously. One child had low bladder compliance postoperatively. Despite the urodynamic changes, no child had clinical urologic problems at further follow-up. Mean follow-up after surgery was 24 months. CONCLUSIONS: This study found that after rectosigmoidectomy below the cul de sac alterations of bladder function can be observed. In 7 of the 11 patients studied, mean cystometric bladder capacity was 87% higher than capacity estimated for age. Moreover, postoperative residuals were 156% higher than the preoperative values. These findings suggest that partial detrusor denervation is likely in these patients. However, because detrusor contractility was present, and none of the children had retention or any urologic problems, the findings must be interpreted carefully. Because children with Hirschsprung's disease generally do not have preexisting urologic problems, routine preoperative urodynamic screening is not necessary. However, children with voiding problems after operation should be investigated urodynamically. For legal reasons parents should be informed of possible urologic problems, especially if subtotal resection of the aganglionic bowel segment is planned.

Colon, Sigmoid↗
PubMed2001

Complications of percutaneous endoscopic gastrostomy with or without concomitant antireflux surgery in 96 children.

BACKGROUND/PURPOSE: A study was conducted of the complications of percutaneous endoscopic gastrostomy (PEG) with or without antireflux surgery (ARS). METHODS: A retrospective review was conducted of all patients, receiving a PEG in the period January 1993 through December 1997. Patients' characteristics including underlying disease, indications, results of preoperative screening, and complications were recorded. PEG placement was performed with the Seldinger technique and, in some cases, under laparoscopic control. In the event of a pathologic pH study during preoperative screening, laparoscopic antireflux surgery (ARS) was added. RESULTS: Mean age was 5 years and 10 months. The majority of the children were mentally retarded. The main indications for PEG were vomiting, food refusal, inability to swallow, and aspiration. Fifty-nine patients had PEG without ARS. Nineteen of these patients had concomitant laparoscopy. Thirty-seven patients had PEG with ARS. One patient died postoperatively of gastric leakage. PEG-related complications occurred in 31% of the patients. There was a significant higher incidence of complications in the group of patients that underwent ARS together with PEG compared with PEG placement without ARS. Roughly half of the complications were peristomal infection related to the use of T-fasteners and the other half gastroduodenal obstruction caused by the balloon of the gastrostomy catheter, both preventable complications. Preoperative vomiting without a positive pH-study disappeared in most cases after PEG placement. Although the pH study normalized in 34 of 37 patients after concomitant ARS, vomiting persisted in 7 of 17 patients. PEG improved the nutritional status in 75% of the children. CONCLUSIONS: PEG improved the nutritional status in the majority of the children. However, PEG placement can lead to a considerable amount of complications, especially when combined with ARS. ARS together with PEG is successful in treating GER but does not necessarily cure preexistent vomiting. PEG alone cures vomiting in 80% of the patients and rarely leads to vomiting. There seems no good reason for combining PEG with ARS. Only if symptoms progress after PEG, ARS should be considered. Caretakers and patients should be well informed before placement.

Adolescent↗
PubMed2001

Pediatric surgery in The Netherlands.

Pediatric surgery in The Netherlands differs from pediatric surgery in other European countries. This article deals with the general structure of Dutch pediatric surgery and some of its particularities. Although pediatric surgery is not officially recognized in The Netherlands, the Dutch have found a way of selecting and centralizing children who need surgical therapy in 6 centers of excellence. This has been mainly achieved by agreements between scientific professional organizations. The limited number of academic pediatric surgical centers guarantees a high quality of skill and care, and a lot of clinical exposure for trainees. On the other hand, allowing general surgeons to do most of the surgery in children, albeit the less complicated procedures, may not be ideal. The limited number of trainees does not allow for a nation-wide training program. The small number of pediatric surgeons and trainees make pediatric surgery in The Netherlands vulnerable, both in field of care as well as in the field of research. As pediatric surgery in The Netherlands is not recognized as such, pediatric surgeons who have been trained in most of the other European countries but have not completed their general surgery training, cannot be employed as pediatric surgeons in The Netherlands. However, pediatric surgery in The Netherlands has found a comparatively clear way of defining its distinctive areas of clinical work. It cannot be overlooked and is well established in the academic centers of the country.

General Surgery↗
PubMed2000

Laparoscopic duodenoduodenostomy for duodenal atresia.

A 3,220-g newborn baby with trisomy 21 presented with duodenal atresia. No other congenital malformations were diagnosed. Informed consent for a laparoscopic approach was obtained. The child was placed in a supine, head-up position slightly rotated to the left at the end of a shortened operating table. The surgeon stood at the bottom end with the cameraperson to his left and the scrub nurse to his right. The screen was at the right upper end. Open insertion of a cannula for a 5-mm 30 degrees telescope through the inferior umbilical fold was performed. A carbon dioxide (CO2) pneumoperitoneum with a pressure of 8 mmHg and a flow of 2l/min was established. Two 3.3-mm working cannulas were inserted; one in the left hypogastrium and one pararectally on the right at the umbilical level. Two more such cannulas were inserted; one under the xyphoid for a liver elevator and one in the right hypogastrium for a sucker. Mobilization of the dilated upper and collapsed lower duodenum was easy. After transverse enterotomy of the upper duodenum and longitudinal enterotomy of the distal duodenum, a diamond-shaped anastomosis with interrupted 5 zero Vicryl sutures were performed. The absence of air in the bowel beyond the atresia increased the working space and greatly facilitated the procedure. The technique proved to be easy, and the child did very well. Laparoscopic bowel anastomosis in newborn babies had not been described previously. Recently, a diamond-shaped duodenoduodenostomy for duodenal atresia was performed. The technique proved to be simple and is described in detail. The child did very well.

Down Syndrome↗
PubMed2000

Laparoscopic refundoplication in children.

BACKGROUND: Gastroesophageal fundoplication currently is one of the three most common major operations performed on infants and children by pediatric surgeons in the United States. With the advent of laparoscopic surgery, the number of gastroesophageal fundoplications has virtually exploded. Morbidity always was substantial with this operation, and laparoscopy has not changed this. We describe our results with laparoscopic refundoplication in infants and children. METHODS: From December 1993 to December 1998 100 children underwent a laparoscopic 180 degrees anterior wrap using the Thal procedure. Four children had to undergo a laparoscopic refundoplication. Two of these children were mentally handicapped. All of the children had recurrent symptoms, but only two of the four had an abnormal pH study. In three of the children, the Thal procedure was changed to a Nissen (n = 2) and Toupet (n = 1) fundoplication. One child with an intrathoracic wrap and a giant hiatal hernia underwent hernia repair with a Goretex patch and a redo-Thal. RESULTS: In two of the children, the operation was relatively simple. For one child, the procedure had to be converted for anesthesiologic reasons. The procedure in the fourth child was more difficult because of a large hiatal hernia. Within a follow-up time of 2 to 4 years, all the children were free of pathologic gastroesophageal reflux symptoms and afterward displayed no recurrence. CONCLUSION: In children, laparoscopic refundoplication after a previous laparoscopic antireflux Thal procedure is feasible and does not increase morbidity.

Adolescent↗
PubMed2000

Laparoscopic secondary antireflux procedure after PEG placement in children. Percutaneous endoscopic gastrostomy.

BACKGROUND: This study investigates the feasibility of performing a subsequent laparoscopic antireflux procedure after former placement of a percutaneous endoscopic gastrostomy (PEG). METHODS: Between 1997 and 1998, five patients with a gastrostomy in place presented with an indication for laparoscopic antireflux procedure due to persisting vomiting. RESULTS: All patients were managed laparoscopically with a four-trocar technique. CONCLUSIONS: Primary PEG placement has no adverse effects on a later secondary antireflux procedure. In some cases, four rather than five trocars can be used.

Child↗
PubMed2000

Physiotherapy as an adjuvant to the surgical treatment of anterior chest wall deformities: a necessity? A prospective descriptive study in 21 patients.

PURPOSE: The authors postulated that physiotherapy as an adjuvant to the surgical treatment of anterior chest wall deformities is only indicated if specific abnormalities can be found that could be corrected by physiotherapy. The purpose of this study is to investigate whether such abnormalities can be found and to evaluate their course during a postoperative period of 18 months. METHODS: Twenty-one patients, 16 with pectus excavatum and 5 with pectus carinatum, were evaluated 6 weeks before and 6 weeks, 6 months, and 18 months after surgical correction. Postural impairments, spinal mobility and curvature, muscle strength, and muscle length were evaluated. RESULTS: Preoperatively, poor posture was seen in 10 patients, nonstructural scoliosis in 11, and abdominal muscle weakness in 4 patients. None of the patients had restriction of spinal mobility or shortened pectoral muscles. Six weeks after surgery, poor posture was seen in 9, nonstructural scoliosis in 11, and abdominal muscle weakness in 10 patients. The authors found a higher percentage of recovery for abdominal muscle weakness than for poor posture (90% versus 33%, respectively). CONCLUSIONS: The authors found preoperative postural impairments in 52% of their patients, in patients with pectus carinatum as well as in patients with pectus excavatum. In patients without postural impairments, physiotherapy is not necessary, with the exception of postoperative pulmonary care.

Abdominal Muscles↗
PubMed2000

Laparoscopy in infants and children: a prospective study on feasibility and the impact on routine surgery.

BACKGROUND/PURPOSE: The feasibility of laparoscopy in children and its impact on routine pediatric surgery are not well established. The purpose of this study was to determine the role of laparoscopy in a university department of pediatric surgery. METHODS: All children undergoing laparoscopy during the period of 1 year were included in a prospective trial. Data on patients, the operation, technical problems, intraoperative events, and the postoperative course were documented using standardized questionnaires. All patients underwent at least 1 follow-up assessment 2 weeks after the operation. All conventional abdominal operations performed during the same period were analyzed for comparison purposes. RESULTS: Of 244 abdominal operations performed during the study period, 147 (60.2%) were laparoscopies. One hundred twenty-three (83.7%) of these included a laparoscopic operation, and 24 (16.3%) were diagnostic procedures. Of 26 types of laparoscopic operations 3 were performed more than 15 times (fundoplication, appendectomy, pyloromyotomy), and 9 types were performed once. Problems with instruments and devices led to a mean time loss of 15.1 minutes in 15.6% of the procedures. The conversion rate was 10.1% mainly because of complicated appendicitis. Fifty-six children (38.1%) weighed less than 10 kg, and the conversion rate did not correlate with the body weight. There was 1 (0.07%) intraoperative event. A small bowel perforation was identified immediately and resolved with an uneventful course. Postoperative complications included an incisional hernia in 3 children and an incisional leakage of liquor in 1 child with a ventriculoperitoneal drain. There was a reprolaps after laparoscopic correction of an ileostomy in 1 child and fever in another. In 3 newborns the diagnosis was missed during laparoscopy and had to be established by laparotomy later with an uneventful course. Primary conventional operations were mainly restricted to bowel resection and anastomosis performed in 52 of 97 laparotomies. CONCLUSIONS: The authors showed that 60% of abdominal operations in children can be performed via laparoscopy. Most types of laparoscopic operations are not performed frequently, but the feasibility of the technique in routine use is excellent. However, the performance of instruments should be improved further, and laparoscopy for establishing the diagnosis in newborns remains difficult.

Abdomen↗
PubMed1999

[Prophylactic total thyroidectomy in childhood for multiple endocrine neoplasia type 2A: preliminary results].

OBJECTIVE: Evaluation of prophylactic total thyroidectomy in childhood in case of MEN2A gene carriership. DESIGN: Retrospective. METHOD: Prophylactic thyroidectomy was performed in 14 MEN2A gene carriers (7 boys, 7 girls; median age 9.1 year (range: 4.8-14.7)), in June 1993-July 1997 at the department Pediatric Surgery of the Wilhelmina Children's Hospital in Utrecht, the Netherlands. Median time between genetic investigation and operation was 5.5 months (range: 2-35). Lymph node dissection was not performed. The parathyroids were identified and left untouched as far as possible, autotransplantation was performed twice because of doubt about viability. Outpatient follow-up took place every 3-6 months. RESULTS: One patient (13.4 year) showed macroscopic, the other 13 microscopic multifocal medullary thyroid carcinoma, 11 bilateral and 3 unilateral. In 1 child (6.2 year) neuroinvasive growth existed already. Surgical sections were free of tumour. After the operation temporary hoarseness occurred once, temporary hypocalcaemia three times and permanent hypoparathyroidism twice; after autotransplantation no hypocalcaemia occurred. Median follow-up was 3.2 year (range: 1 month-4.0 year). Mild psychological problems were observed in 4 patients, psychiatric problems in 1. CONCLUSION: Prophylactic total thyroidectomy during the first decade is recommended. Additional lymph node dissection and total parathyroidectomy are unnecessary than. In order to prevent postoperative hypoparathyroidism, autotransplantation of at least one parathyroid is advisable.

Adolescent↗
PubMed1999

Malignant pancreatic tumour within the spectrum of tuberous sclerosis complex in childhood.

UNLABELLED: A 12-year-old boy with tuberous sclerosis complex (TSC) presented with a large retroperitoneal tumour. Exploratory surgery revealed an infiltrative tumour originating from the pancreas, with local metastases to the lymph nodes. The histologal diagnosis was a malignant islet cell tumour. Retrospectively measured pancreatic hormone levels, however, were normal. A connection between the malignancy and TSC was demonstrated by loss of heterozygosity of the TSC2 gene in the tumour. The primary mutation Q478X in this patient was identified in exon 13 of the TSC2 gene on chromosome 16. CONCLUSION: Pancreatic islet cell tumours have been mainly associated with multiple endocrine neoplasia syndrome type 1. In our case we demonstrate a direct relationship of this tumour to tuberous sclerosis complex, in the absence of further signs of multiple endocrine neoplasia syndrome type 1.

Carcinoma, Islet Cell↗
PubMed1999

The value of 24-h pH study in evaluating the results of laparoscopic antireflux surgery in children.

BACKGROUND: The performance of laparoscopic antireflux surgery is steadily increasing among pediatric surgeons. Different techniques are being used. However, due to a lack of standardized follow-up methods, postoperative results are difficult to compare. In this study, we describe the results of postoperative 24-h pH study as an objective criterion for evaluating the results of laparoscopic Thal antireflux surgery. METHODS: In a prospective study, 53 patients underwent a laparoscopic Thal procedure. Preoperatively, all patients were subjected to 24-h pH monitoring, an upper GI series, and esophagogastroscopy. pH monitoring was performed 3 months postoperatively to evaluate the effect of the fundoplication. Esophagogastroscopy was repeated in case of preoperative esophagitis. RESULTS: In one patient, the laparoscopy was converted to an open procedure. Feeding was commenced on day 1 in 49 of the 53 children. Mean hospitalization time was 4.4 days. One patient was reoperated for a too-tight fundoplication, and two patients died of unrelated causes. Ultimately, 44 of 50 children (88%) were free of symptoms; however, 11 of 41 children (25%) still displayed pathological reflux on pH monitoring. CONCLUSIONS: The Thal fundoplication can be performed laparoscopically in children. Children have a quick recovery, and hospitalization is short (4.4 days). At follow-up, nearly 90% of the children are free of symptoms. However, 25% still have pathological reflux as measured with pH monitoring. Therefore, questionnaires alone are not a sufficient means of measuring outcome postoperative. pH monitoring is a valuable additional tool for the objective postoperative evaluation of the results of (laparoscopic) antireflux procedures.

Child↗
PubMed1999

Management of adhesive bowel obstruction in children is changed by laparoscopy.

BACKGROUND: With new advances in diagnostic and therapeutic tools, the early management of adhesive bowel obstruction has become feasible. METHODS: In a retrospective study, 20 children with adhesive bowel obstruction were investigated to assess the possible advantages of the laparoscopic approach. RESULTS: Laparoscopy was performed in nine children. Six of them were managed laparoscopically. Recovery was uneventful. In two children, extensive adhesions warranted elective conversion. The single complication occurred in a child with obstruction of the colon due to perforation caused by a small instrument. Eleven children underwent primary laparotomy for adhesive obstruction. Five of them had a single band and might have benefited from a laparoscopic approach. CONCLUSIONS: Laparoscopic management of adhesive bowel obstruction in children is feasible and safe in experienced hands. Early management saves the child a great deal of discomfort and allows a quick recovery with early discharge.

Adolescent↗