G. Martucciello

GDNF deficit in Hirschsprung's disease.

BACKGROUND/PURPOSEnIn 1996, the glial cell line-derived neurotrophic factor (GDNF) was identified as one of the ligands of the RET transmembrane receptor. In the same year, GDNF mutations were found in association with RET protooncogene mutations in Hirschsprung patients. Mutations in GDNF per se are thought neither necessary nor sufficient to cause Hirschsprungs disease (HD). To date, our study group has identified GDNF mutations only in 2 of 98 cases of intestinal dysganglionosis. The aim of our study was to investigate a possible expression deficit of GDNF in the enteric nervous system of Hirschsprung patients not mutated for the GDNF gene.nnnMETHODSnWe used rabbit polyclonal antibodies raised against a peptide corresponding to amino acids 186-205 mapping within the carboxy-terminal domain of human GDNF. GDNF expression was studied immunohistochemically in surgical specimens from 30 HD cases (27 classic forms and 3 ultralong forms) and from 10 age-matched controls. Serial sections from the same full-thickness specimens were investigated with the following histochemical and immunohistochemical techniques: acetylcholinesterase, lactate dehydrogenase, succinic dehydrogenase, alpha-naphthyl-esterase, glial fibrillary acid protein, S-100 protein, and neuron-specific enolase.nnnRESULTSnA high level of GDNF expression was found in normal intestine and in Hirschsprung ganglionic segment. Satellite elements of myenteric ganglia presented a strong immunoreactivity to GDNF. Conversely, the aganglionic segment showed cholinergic hyperinnervation and hypertrophic trunks of nerve fibers in the muscular interstitium with complete absence of GDNF expression. The small ganglia of the hypoganglionic segment showed a reduced GDNF immunoreactivity.nnnCONCLUSIONSnGDNF, a distantly related member of the transforming growth factor-beta superfamily, is a potent neurotrophic and survival factor for neurons and enteric ganglion cells. Mutations of the GDNF gene or GDNF expression deficit interrupt the faithful GDNF signaling via Ret, contributing to HD pathogenesis.

Total Colonic Aganglionosis

The authors describe the genetic, pathophysiology, diagnostic, and therapeutic aspects of total colonic aganglionosis and of aganglionosis extending to the small intestine. The pathogenesis of this disease is genetically determined and is related to the differentiation and migration of cells derived from neural crests. The clinical and radiological features can be useful in the diagnosis but they are not pathognomonic. The histochemical estimation of acetylcholinesterase activity in suction rectal biopsies is useful in establishing the diagnosis; however, the specimens should be examined by an experienced pathologist. The definitive diagnosis of either condition is obtained by performing intraoperative seromuscular biopsies of the rectum, colon, and ileum. From the therapeutic point of view, many surgical techniques have been proposed for the radical treatment of this disease. Some of the techniques have been derived from operations proposed for the treatment of classic Hirschsprungs disease; others have been specifically designed.

Histologic study of peritoneal adhesions in children and in a rat model

Abstract.Peritoneal adhesions (PA) represent a major cause of morbidity in pediatric surgical patients. The pathogenesis is still largely unknown. A possible role could be played by foreign bodies (FB) accidentally contaminating the operative field during surgery. We report a histologic study of PA in a rat model and in children, investigating the role of FB in their formation. Abdominal adhesions were studied in 18 rats. In 6 (group A) we performed a laparotomy and rubbed the visceral and parietal peritoneum with a cotton bud. In 6 (group B) we performed a minimal laparotomy and injected powdered autologous and heterologous material into the peritoneal cavity, avoiding any peritoneal abrasions. In 6 (group C) we performed a laparotomy and applied both treatment methods, i.e., rubbing and injection of FB. After 1 month, at autopsy rats were classified according to the presence and grade of surgical adhesions. Twenty-two PA were also collected from seven children undergoing abdominal surgery in whom one or more procedures had been previously performed. The adhesions were stained with hematoxylin-eosin and Giemsa stains for histologic examination. Adhesions were found in 4 rats of group A and all 6 rats of group C. None were identified in group B. Group C rats showed a higher grade of adhesions with respect to group A. In both humans and animals PA were always found to coexist with microscopic particles of solid substances, which were incorporated inside the connective tissue. However, after simple injection of FB into the abdominal cavity we did not observe any PA. These data suggest that two different stimuli are necessary for adhesion formation: a direct lesion of the mesothelial layers and a solid substrate (FB). We underline the importance of reducing contamination with FB during surgery. On the basis of these considerations, the laparoscopic approach seems to be particularly pertinent.

Search for pathogenetic variants of the SPRY2 gene in intestinal innervation defects

SPRY2 is an inducible inhibitor of signalling mediated by tyrosine kinases receptors, whose targeting causes intestinal hyperganglionosis in mice. In this light, we have undertaken a mutational analysis of the SPRY2 gene in patients affected with intestinal neuronal dysplasia (IND), without detecting nucleotide changes in any of the 26 DNA samples analysed, with the exception of two already known polymorphic variants. A role of the SPRY2 gene in IND pathogenesis can be thus excluded.

Feasibility of perineal sagittal approaches in patients without anorectal malformations

Perineal sagittal approaches (posterior sagittal anorectoplasty and anterior and posterior sagittal transanorectal approaches) allow complete anatomic exposure of the perineum and lower pelvis. Moreover, they reduce the risk of damaging important structures because the incision is led in the midline. Therefore, many surgeons have used these approaches to treat diseases other than anorectal malformations (ARM), including intestinal dysganglionosis, trauma, pseudohermaphroditism, presacral mass, and rectal duplication. The aim of this study was to describe a small series of patients operated on via these approaches at Gaslini Children’s Hospital over a 5-year period. We retrospectively evaluated 10xa0patients consecutively operated on via a perineal sagittal approach, with or without sphincteric structure involvement, between January 1997 and December 2001. All of these patients were without ARM. Indications included retrorectal abscesses (two), iatrogenic anal canal stenosis (one), postinflammatory anal canal stenosis (one), internal anal sphincter neurogenic achalasia (one), female pseudohermaphroditism (one), benign sacrococcygeal teratomas (two), malignant sacrococcygeal teratoma (one), and perineal rhabdomyosarcoma (one). Protective colostomy was used in four patients. The parameters that we analysed included technical details, possible complications, perineal cosmetic appearance, and outcome. No complications were experienced. The postoperative cosmetic perineal appearance was excellent in all patients, and continence, when assessed, was always considered satisfactory. All tumours underwent complete gross resection. However, one patient with malignant sacrococcygeal teratoma died as a result of the malignant process 2xa0years after surgery. Although our study was carried out on a small series of patients, it confirmed that perineal sagittal approaches can be used not only for ARM but also for other conditions involving perirectal pouches, presacral space, and urogenital structures, as these approaches are safe and provide excellent cosmetic results as well as satisfactory functional outcome. Although tumours can be treated via these approaches, outcome remains related to the nature and malignancy of the disease itself.

Soave's extramucosal endorectal pull-through procedure

The use of the abdominal extramucosal dissection of the rectal pouch was first proposed by Romualdi at the Roman Society of Surgery on 15 May 1955. The technique was first published in 1960 [1]. During the next few years, Rehbein [2] and Kiesewetter and Turner [3] also popularized this operation. In 1957, Soave started using Romualdi’s procedure for the treatment of anorectal malformations with urethral fistula. Since his initial experience with Romualdi’s technique, he thought that this principle could be applied for the treatment of Hirschsprung’s disease (HSCR). So, in 1961, he performed his first operation on a 2-year-old boy with the classic form of HSCR.