Hirschsprung's disease in young adults

Hirschsprung's disease is rarely seen in the young adult, and presents unique problems in management because of the massive dilatation and hypertrophy that occur proximal to the aganglionic rectum or the rectosigmoid colon. The diagnosis, which may be suspected by barium enema, is confirmed by suction or full-thickness biopsy of the rectum that may be complemented by anal manometry. Based on our experience with eight patients, a two-stage surgical reconstruction is recommended, with a preliminary sigmoid colostomy through the normally innervated colon and an associated defunctionalized stoma constituting the initial operation. The distal colonic stoma permits cleansing of the caudal colon while the normally innervated proximal colon reverts to near normal caliber, usually within 2 to 6 months. This approach is in accord with the recommendation of Fairgrieve. Reconstruction using a Duhamel or Soave procedure has given good results. The Duhamel procedure seems preferable when a considerable discrepancy remains between the ganglionic and aganglionic segments of rectum.     

Hereditary spherocytosis. Recent experience and current concepts of pathophysiology.

Hereditary spherocytosis is a clinically heterogeneous, genetically determined red blood cell membrane disorder resulting in hemolytic anemia. A deficiency of spectrin, the largest and most abundant structural protein of the erythrocyte membrane skeleton, results in the formation of spherocytes which lack the strength, durability, and flexibility to withstand the stresses of the circulation. Clinical manifestations of the disease are primarily dependent on the severity of hemolysis, which additionally results in an increased incidence of pigment gallstones. The likelihood of cholelithiasis is directly related to patient age and is uncommon before 10 years of age. Splenectomy is indicated in virtually every patient. When the disease is diagnosed in early childhood, the risk of overwhelming postsplenectomy sepsis makes it advisable to delay splenectomy until after 6 years of age if possible. At the time of splenectomy, it is important to identify and remove any accessory spleens. If gallstones are present, cholecystectomy should be performed. Although spherocytosis persists following splenectomy, hemolysis is alleviated and clinical cure of the anemia is achieved for most patients. Patients with recessively inherited spherocytosis are exceptions. Although they are significantly benefited by splenectomy, their anemia is not completely corrected. Splenectomy reduces hemolysis in all patients and thereby decreases the risk for development of pigment gallstones. Excision of an enlarged spleen removes the danger of traumatic rupture.     

Combination of ABO blood group incompatibility and glucose-6-phosphate dehydrogenase deficiency: effect on hemolysis and neonatal hyperbilirubinemia

The incidence (%) of hyperbilirubinemia (serum bilirubin ≥257 μmol/l) was similar in neonates with a combination of ABO incompatibility and glucose-6-phosphate dehydrogenase (G-6-PD) deficiency (45%), with ABO incompatibility (54%) or G-6-PD deficiency (37%), alone (ns). Carboxyhemoglobin values, corrected for inspired CO, were similarly elevated in all three groups (0.87 ± 0.32%, 0.82 ± 0.29%, 0.76 ± 0.18%, respectively, ns), but correlated with bilirubin only in those with ABO incompatibility alone. ABO-incompatible/G-6-PD-deficient neonates, compared with those with either condition alone, are not at increased risk for hemolysis or hyperbilirubinemia.     

Le traitement familial des enfants et des adolescents anorexiques : Des lignes directrices pour le m��decin communautaire

Anorexia nervosa (AN) is a serious life-threatening illness that typically has its onset during the adolescent years. Evidence regarding the optimal treatment of AN in children and teenagers is growing; however, much remains unknown. Although current treatment approaches vary in Canada and elsewhere, the evidence to date indicates that family-based treatment (FBT) is the most effective treatment for children and teenagers with AN. A key component of the FBT model is that the parents are given the responsibility to return their child to physical health and ensure full weight restoration. An understanding of the basic principles and philosophy underlying FBT allows the physician to initiate elements of this evidence-based intervention to young patients with AN and their families.     

Role of extracellular adenosine triphosphate in the cytotoxic T- lymphocyte-mediated lysis of antigen presenting cells

The lysis of antigen presenting cells (APCs) by cytotoxic T lymphocytes (CTLs) may be one mechanism whereby an immune response is downregulated by Staphylococcus superantigens. Disappearance of monocytes/macrophages from staphylococcal enterotoxin A (SEA)-activated peripheral blood mononuclear cell (PBMC) cultures, but not from control PBMC cultures was seen by flow cytometry. Recently, adenosine triphosphate (ATP) has been described as an effector molecule in CTL-mediated lysis of some murine tumor target cells. We have also shown that ATP caused the lysis of human macrophages, and that treatment of cells with interferon gamma (IFN gamma) rendered macrophages significantly more sensitive to ATP than untreated cells. To show that this purine nucleotide may play a role in modulating the immune system, we generated human CTLs that were stimulated with SEA, and used them as effector cells against SEA-pulsed autologous macrophages. CTLs were found to specifically lyse SEA-pulsed macrophages, while control, unpulsed, macrophages were unaffected. The addition of hexokinase, an enzyme that hydrolyzes ATP, significantly abrogated the killing of SEA-pulsed cells during the assay. In examining the mechanism of cytotoxicity, electron microscopy showed that macrophages incubated with both ATP and CTLs underwent necrosis, rather than apoptosis. From these results, it is suggested that ATP is released from CTLs during antigen presentation, and that IFN gamma- activated macrophages, which are inherently more sensitive to this mediator, are readily lysed and therefore removed from circulation, thus downregulating an immune response.