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Biomedical subjects

P M Colombani

Publications and source records attributed to P M Colombani.

At least 19 recordsLinked to original sources

Atypical thrombotic and septic complications of totally implantable venous access devices in patients with cystic fibrosis.

The use of vascular access systems in patients with cystic fibrosis (CF) is well accepted, with lower overall complications and maintenance costs than percutaneous silastic catheters. We report our 6 year experience with 22 infusaports in 15 CF patients. Our patients had indwelling catheters for an average of 539 days per catheter (range, 14-2,224 days). These infusaports were used for home antibiotic therapy, blood sampling, and total parenteral nutrition. The overall complication rate was relatively low, 1 in every 1,483 catheter days. Infectious complications were extremely infrequent at a rate of 1 in 5,929 catheter days. The rate of mechanical complications was 1 in 1,976 catheter days. However, superior vena caval syndrome or deep venous thrombosis was associated with 3 of 22 catheters (13.6%). Due to this high incidence of major thrombotic events with the attendant risk of pulmonary embolism, all patients with CF using infusaports and without evidence of liver disease or bleeding problems receive aspirin prophylaxis.

Adolescent

Diagnosis and management of congenital vascular rings: a 22-year experience.

Between 1968 and 1990, we operatively treated 39 patients (19 boys, 20 girls) with congenital aortic arch anomalies. Median age was 7 months (range, 1.5 months to 23 years). Thirty-seven patients (95%) had respiratory symptoms. Barium swallow was diagnostic in 95%. Right arch with aberrant left subclavian artery and double aortic arch were the most common types (11 each). Treatment of an aortic diverticulum was documented in 19 patients; the aortic diverticulum was excised (9), managed by aortopexy (7), or left in situ (3). Postoperative recovery was rapid, with a median intensive care unit stay of 2 days, time to oral feeding of 1 day, and postoperative time to discharge of 7 days. Two deaths occurred: 1 infant had undergone emergent operation for control of hemorrhage from an aortotracheal fistula due to tracheostomy tube erosion, and the other had multiple associated congenital heart defects. Postoperative complications included bleeding (1), pneumonia (5), and chylothorax (4). One boy had persistent severe symptoms due to an untreated aortic diverticulum and underwent subsequent excision of the aortic diverticulum with complete relief of symptoms. Median length of follow-up was 12.5 months, with at least 97% of survivors completely or nearly completely free of symptoms from the vascular ring. These results suggest that early repair of congenital aortic vascular rings, including fixating or excising an associated serious aortic diverticulum, is safe and effective and allows for normal tracheal growth.

Adolescent

Treatment of recurrent and refractory pediatric solid tumors with high-dose busulfan and cyclophosphamide followed by autologous bone marrow rescue.

PURPOSE: The purpose of this study was to determine the toxicities of and responses to high-dose busulfan and cyclophosphamide with autologous bone marrow transplant (ABMT) in patients with recurrent or refractory pediatric solid tumors. PATIENTS AND METHODS: We treated 18 patients (ages, 2 to 38 years; median, 14) who had tumors that were resistant to conventional chemotherapy and radiotherapy with busulfan 16 mg/kg and cyclophosphamide 200 mg/kg. Seventeen patients received bone marrow purged with 4-hydroperoxycyclophosphamide; one received unpurged marrow. RESULTS: Despite extensive prior treatment, including radiotherapy in 16 patients, toxicity generally was acceptable. For seven patients with measurable disease, there were three partial responses of 2, 10, and 20 months' duration, three patients with stable disease (SD), and one early, toxic death. Of the 11 patients with no measurable disease at the time of transplantation, one patient with osteosarcoma continues in remission at 57+ months and one third of the patients survived for at least 16 months. Mucositis was the predominant nonhematopoietic toxicity. CONCLUSION: Although the high-dose busulfan and cyclophosphamide combination showed modest activity, changes in the preparative regimen should be considered to improve the response rate in refractory tumors.

Adolescent

The ontogeny of the gut-associated lymphoid tissue in short bowel syndrome.

Newborns suffering from short bowel syndrome (SBS) after massive intestinal resection have numerous infectious complications, which may be due to immunoincompetence from the loss of gut-associated lymphoid tissue (GALT). This study examines the ontogeny of GALT in the rat with SBS. A total of 36 3-week-old rats were divided into two groups: I, sham operated (C, n = 16); and II (SBS, n = 20), with a 50% resection of small intestine with jejunoileostomy. At 4, 5, 6, and 10 weeks of age the animals were sacrificed and the GALT was assessed by video analysis and immunoperoxidase monoclonal antibodies, OX8 (CD8), W-3/25 (CD4), and MARA-2 (IgA). The data were expressed as positive staining lymphocytes per 10(4) microns2 (mean +/- SD). table; see text In the sham group there was an increase in all lymphocyte subsets over time. In the SBS group there was a rapid fall in OX8 and W-3/25 T-lymphocytes by 10 weeks, with no increase in IgA plasma cells at 6 and 10 weeks. This study demonstrates that in the massive bowel resection in the suckling rat decreases the T- and B-lymphocyte populations in the GALT. This lack of development may underlie the associated infectious complications and malabsorption in SBS.

Animals

Superior mesenteric vein inflow for liver transplantation when the portal vein is occluded.

An alternative solution to the problem of liver transplantation in the patient with an occluded portal vein is described. It uses a bridge graft of donor iliac vein from the superior mesenteric vein at the base of the colonic mesentery. The graft is tunnelled over the pancreas and under the stomach to the region of the liver hilum to provide portal inflow. This procedure was employed successfully in four patients, with patency for more than 2 years in the patient with the longest follow-up. By this approach it is routinely possible to perform a transplant procedure in a recipient with an occluded portal vein.

Adult

Neonatal diagnosis of a presacral mass in the presence of congenital anal stenosis and partial sacral agenesis.

The simultaneous presentation of clinically symptomatic anal anomalies and roentgenographically demonstrated sacral dysgenesis should alert the pediatric surgeon to investigate for the presence of a presacral malformation. We report on such a case to illustrate a new radiographic technique that facilitates diagnosis and management of complex congenital malformations. A 1-day-old white boy presented with anal stenosis, a scimitar-shaped sacrum, and large anterior and posterior meningoceles. In addition, a distinct presacral tumor--a teratoma--was identified. These malformations were identified utilizing metrizamide myelography and three-dimensional reconstruction computed tomography (CT) scanning. The meningoceles and a tethered cord were successfully corrected utilizing a posterior approach. A diverting colostomy was performed and subsequently taken down. Two years postoperatively, the patient continues to do well. This case demonstrates that this triad of anomalies (presacral mass, sacral dysgenesis, and anorectal malformation), once considered, can be safely detected with modern radiologic techniques and can be expeditiously corrected during infancy before further deterioration occurs.

Abnormalities, Multiple

Prediction of successful primary closure of congenital abdominal wall defects using intraoperative measurements.

To determine whether intragastric pressure (IGP) and central venous pressure (CVP) would reliably predict successful primary closure of congenital abdominal wall defects (omphalocele/gastroschisis) in newborn infants, we developed the following prospective intraoperative management protocol. Following a temporary trial of fascial closure, infants who had an IGP less than 20 mm Hg or an increase in CVP of less than 4 mm Hg were primarily closed. If IGP was greater than 20 mm Hg or if CVP increased by more than 4 mm Hg, the temporary closure of the abdomen was reopened and a prosthetic silo was placed. Ten infants who were less than 24 hours old and averaged 2.7 kg (range, 1.4 to 4.2 kg) and 37-weeks gestation (range, 32 to 41 weeks) were studied. Eight infants met criteria for primary closure. Their IGP averaged 14 +/- 4 mm Hg (+/- SD) (range, 8 to 19 mm Hg), and their increase in CVP averaged 1 +/- 2 mm Hg (range, -2 to 3 mm Hg). In the two infants who required staged repair, IGP averaged 25 +/- 1 mm Hg (+/- SD) (range, 24 to 25 mm Hg), and the increase in CVP averaged 7 +/- 1 mm Hg (range, 6 to 8 mm Hg). All patients were anesthetized with fentanyl (12.5 micrograms/kg) and paralyzed with metocurine (0.3 mg/kg) intraoperatively. There were no postoperative complications in either group of patients related to increased intraabdominal pressure, and all patients were extubated within 48 hours of the initial surgery. We conclude that the intraoperative measurement of changes in IGP and CVP can serve as a guide to the operative management of congenital abdominal wall defects and can reliably predict successful outcome following repair.

Abdominal Muscles

Evolving management of pectus excavatum based on a single institutional experience of 664 patients.

Most pediatricians and family physicians believe that children with pectus excavatum require surgery only for cosmetic indications and then only in teenagers. We believe pectus excavatum should be repaired in childhood (1) to relieve structural compression of the chest and allow normal growth of the thorax; (2) to prevent pulmonary and cardiac dysfunction in teenagers and adults; and (3) to obviate the cosmetic impact that may cause a child to avoid sports and gymnastics. Preoperative CT scans now help select those children who need repair to prevent progressive deformities. Pulmonary function studies during vigorous exercise can document respiratory dysfunction in teenagers. These features are reversible if repair is completed before the pubertal growth spurt. The ideal age for repair is 4 to 6 years, which permits enough emotional maturity for a positive hospital experience and avoids later psychological effects. Repair at an earlier age has no operative advantages. Our operative technique consists of the removal of three to four overgrown costal cartilages, repositioning of the sternum with a transverse osteotomy, and internal support using the child's lowest normal ribs, avoiding any prosthetic support. To prevent recurrence in teenagers, we add a temporary bar beneath the sternum to prevent depression of the sternum from the weight of the chest-wall muscle mass. Six hundred sixty-four patients have been followed for 1 to 40 years; 95% have excellent long-term results and only 5% have mild to moderate recurrences. Our current techniques of patient selection and surgery will be presented.

Adolescent

Inverse correlation of cyclosporine binding with sensitivity and resistance.

The primary effects of CsA on human lymphocyte responses in vitro appear to be the inhibition of IL-2 production and the inhibition of cytotoxic T cell activation. Induction of suppressor T cell activity is resistant to the effects of CsA. These data imply two distinct subsets of lymphocytes: CsA-resistant and CsA-sensitive. The current studies used a bioactive, dansylated derivative of CsA (dans-CsA), which is fluorescent, to assess binding of CsA at the single-cell level by flow cytometry. The results demonstrate that two populations of cells can be distinguished based on differential staining with dans CsA--a weakly staining subset and a population that binds intensely. Both subsets consist of CD4 (helper) and CD8 (cytotoxic/suppressor) T lymphocytes. Functional analysis revealed that the weakly staining subset consists of IL-2-producing T cells and precursor cytotoxic T lymphocytes. On the other hand, the intensely staining subset includes T cells that suppress in an antigen-specific manner after activation with alloantigen. Further studies showed that the weakly staining subset is markedly sensitive to the immunosuppressive effects of CsA in a PHA stimulation assay, while the intensely binding population is markedly resistant, requiring 10- to 100-fold more CsA to inhibit the PHA response. These studies suggest that sensitivity and resistance to CsA is inversely correlated with binding.

Antigens, Differentiation