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Dive into the research topics where Gerardo Prieto is active.

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Featured researches published by Gerardo Prieto.


Journal of Pediatric Gastroenterology and Nutrition | 1992

Helicobacter pylori infection in children : clinical, endoscopic, and histologic correlations

Gerardo Prieto; Isabel Polanco; J. Larrauri; Lucia Rota; Rosa Lama; Sira Carrasco

We have assessed 270 consecutive patients (age range 0.8–20 years) referred for endoscopic study because of abdominal pain during 32 months. Helicobacter pylori (HP) was detected by culture in 91 cases (33.7%). HP colonization increased significantly with age (p < 0.01). Nine patients <5 years of age were colonized by HP. A previous history of peptic ulcer disease in first-degree relatives was significantly more frequent in the HP-positive group (p < 0.001). The frequency of HP positiveness as related to diagnosis was: normal, 3.3%; non-active chronic gastritis, 100%; active chronic gastritis, 97.2%; gastric ulcer, 75%; and duodenal ulcer, 90.9% (p < 0.001). Endoscopic nodular antritis was a frequent (67%) and specific finding; this presence was associated with that of lymphoid follicles in the histopathological study. Signs of histological activity were observed in 55.9% of the HP-positive patients. The histological colonization by HP was assessed semiquantitatively, and a significantly greater HP colonization score was observed in patients with signs of histological activity (p < 0.001). A significant correlation was found between HP colonization score and histological score (rs = 0.574), with a significant association between the degree of HP colonization and the histologic categories (p < 0.001). The present study suggests a pathogenic role of HP in the development of gastroduodenal disease in children.


Journal of Pediatric Surgery | 1995

Ambulatory 24-hour manometric and pH metric evidence of permanent impairment of clearance capacity in patients with esophageal atresia

Juan A. Tovar; Juan A. Diez Pardo; Javier Murcia; Gerardo Prieto; Manuel Molina; Isabel Polanco

Dysphagia and gastroesophageal reflux (GER) probably caused by structural disorganization of the esophagus occur frequently after repair of tracheoesophageal fistula (TEF), and the extent to which they may improve beyond childhood is not known. The aim of the present study is to assess by combined ambulatory 24-hour manometry and pH-metry the esophageal peristaltic activity and acid clearing capacity in adolescents and adults who had been operated on for TEF at birth. Twenty-two patients, aged 17.1 +/- 4.5 years (mean +/- SD), were examined with combined three-channel manometry and two-channel pH-metry followed by endoscopy and biopsy. Although they considered themselves healthy, on careful interrogation, 16 (72%) were found to have dysphagia, 13 (59%) had heartburn, 10 (45%) had foreign body impaction, and 7 (31%) had chronic respiratory tract disease. GER was detected in 12 (54%) patients (5 with histological esophagitis), 10 of whom had a pattern of prolonged nocturnal episodes with very slow clearance. All patients had diminished contractile activity with low-amplitude and short-duration waves that decreased from 0.53 +/- 0.35 waves per minute to 0.28 +/- 0.2 waves per minute during sleep. Propulsive activity was uniformly disorganized, with peristaltic sequences being few (less than 50% overall) and incomplete (above 80%). Finally, the acid-clearing capacity was nil; the proportions of ineffective sequences were above 90% for all periods considered, including sleep and mealtimes. The motor behavior of nonrefluxing and refluxing patients was identical despite the differences in esophageal acid exposure.(ABSTRACT TRUNCATED AT 250 WORDS)


Journal of Pediatric Gastroenterology and Nutrition | 1998

Functional Results of Laparoscopic Fundoplication in Children

Juan A. Tovar; Pedro Olivares; Mercedes Diaz; Rosa A. Pace; Gerardo Prieto; Manuel Molina

BACKGROUND There is no evidence that the results of laparoscopic fundoplication in children match those of the open procedure. In the current report, pre- and postoperative function of the antireflux barrier is examined in children having laparoscopic fundoplication for gastroesophageal reflux. METHODS Twenty-seven patients with gastroesophageal reflux, aged 7.2+/-4.5 years, were operated on for unremitting gastrointestinal symptoms (n = 24), with respiratory tract disease (n = 11), cystic fibrosis (n = 2), or brain damage (n = 11). Gastrostomy was added in 5 cases. Barium contrast study, pH-metering, endoscopic examination, and biopsy were performed before and after a median of 19 months (range, 8 to 46) after operation. RESULTS At diagnosis, 15 of 21 patients had esophagitis that was moderate or severe in 11 (1 with Barretts esophagus). Symptoms disappeared after fundoplication in all but 2 patients, in whom they became milder. The reflux index decreased from 20.2+/-20% to 4.9+/-9% and became normal in all except 4 children (2 with brain damage and 1 with cystic fibrosis). Open repair of the failed wrap was considered necessary in only 1 of them. CONCLUSIONS Laparoscopic fundoplication is as effective as the open procedure (14% overall failure rate). However, the failure rate in neurologic patients (18%) suggests that before reaching conclusions on the benefits of this approach, careful long-term assessment of the functional results is necessary.


Journal of Pediatric Surgery | 2010

Graft-vs-host disease after small bowel transplantation in children

Ane M. Andres; Manuel Lopez Santamaria; Esther Ramos; Jesús Sarría; Manuel Molina; Francisco Hernandez; Jose Luis Encinas; Javier Larrauri; Gerardo Prieto; Juan A. Tovar

PURPOSE Graft-vs-host disease (GVHD) is a rare complication of transplantation of organs rich in immunocompetent cells. The goal of this study was to report the features of GVHD after small bowel transplantation (SBTx) in children. METHODS The study involved a retrospective review of patients undergoing SBTx between 1999 and 2009 who had GVHD. RESULTS Of 46 children receiving 52 intestinal grafts (2 liver-intestine and 3 multivisceral), 5 (10%) developed GVHD. Median age at transplant was 42 (19-204) months. Baseline immunosupression consisted of tacrolimus and steroids supplemented with thymoglobulin (n = 2) or basiliximab (n = 3) for induction. Median time between transplantation and GVHD was 47 (16-333) days. All patients had generalized rash, 2 had diarrhea, and 2 had respiratory symptoms. Other symptoms were glomerulonephritis (n = 1) and conjunctivitis (n = 1). Four developed severe hematologic disorders. The diagnosis was confirmed by skin biopsy in 4 patients and supported by chimerism studies in two. Colonoscopy and opthalmoscopic findings were also suggestive in one. Treatment consisted of steroids and decrease of tacrolimus, with partial response in four. Other immunosuppressants were used in refractory or recurrent cases. Three patients died within 4 months after diagnosis. CONCLUSION Graft-vs-host disease is a devastating complication of SBTx, with high mortality probably associated with severe immunologic dysregulation.


Journal of Pediatric Surgery | 1998

Esophageal function in achalasia: Preoperative and postoperative manometric studies

Juan A. Tovar; Gerardo Prieto; Manuel Molina; Jesus Arana

BACKGROUND/PURPOSE Aperistalsis observed in children with achalasia may be secondary to sphincteric spasm or reflect a primary esophageal dysfunction. The aim of this study was to assess manometrically sphincteric function and esophageal motility before and after successful myotomy. METHODS Conventional stationary and pull-through manometry were performed preoperatively in 14 patients and postoperatively in 13. Ambulatory 24-hour manometry was carried out in four and eight patients in these two groups, respectively, and the results were compared with those of 23 refluxing youngsters. RESULTS Sphincter hypertony with lack or incompleteness of relaxation was found preoperatively in all patients, and sphincter pressure decreased dramatically after myotomy in all of them. All patients had aperistalsis preoperatively, and only a few had some primary, but weak, contractions postoperatively. Ambulatory manometry results confirmed a reduced number of motor events even during meals and only insignificant improvement of progressiveness, completeness and amplitude of waves after myotomy irrespective of the time elapsed since the procedure, the degree of recovery of esophageal caliber, and the clinical outcome. CONCLUSIONS Motor disorders in achalasia in children are similar to those of adults with the same disease. Motor recovery is observed only in some patients, although it is never complete, and their esophagi will remain ineffective for life. Because myotomy destroys the sphincter, and motility is permanently impaired in this condition, a fundoplication must be interposed to allow long-term mucosal protection.


Pediatric Transplantation | 2010

The use of sirolimus as a rescue therapy in pediatric intestinal transplant recipients

Ane M. Andres; Manuel Lopez Santamaria; Esther Ramos; Francisco Hernandez; Gerardo Prieto; Jose Luis Encinas; N. Leal; Manuel Molina; Jesús Sarría; Juan A. Tovar

Andres AM, Lopez Santamaría M, Ramos E, Hernandez F, Prieto G, Encinas J, Leal N, Molina M, Sarría J, Tovar JA. The use of sirolimus as a rescue therapy in pediatric intestinal transplant recipients.
Pediatr Transplantation 2010: 14: 931–935.


Journal of Pediatric Gastroenterology and Nutrition | 2008

Safety and efficacy of granulocyte and monocyte adsorption apheresis in paediatric inflammatory bowel disease: a prospective pilot study.

Javier Martín de Carpi; Pere Vilar; Gerardo Prieto; María Dolores García Novo; Carmen Ribes; Vicente Varea

Objective: Selective granulocyte-monocyte adsorption (GMA) apheresis is a safe technique that has shown efficacy in inflammatory bowel disease (IBD), especially in adult steroid-dependent and steroid-refractory ulcerative colitis. GMA apheresis is performed with Adacolumn, a direct blood perfusion system that selectively adsorbs circulating granulocytes and monocytes. Studies on efficacy of GMA apheresis in paediatric IBD are scarce. Our aim was to evaluate efficacy, safety, and tolerability of GMA apheresis in paediatric IBD patients followed for 1 year. Patients and Methods: Nine patients with a mild to moderate flare-up (6 boys, 3 girls; 5 ulcerative colitis [UC], 4 Crohn disease [CD]) were included. Mean age at inclusion was 13 years and 9 months, and mean disease duration before inclusion was 28 months. All of our patients with UC were steroid-dependent; patients with CD had been unsuccessfully treated with other therapies. GMA apheresis consisted of 5 consecutive weekly sessions lasting 60 minutes each. Results: After the 5 sessions, 4 of 5 patients with UC and 1 of 4 patients with CD achieved remission. This remission was maintained in 2 of 4 patients with UC and in the single patients with CD. Patients taking steroids could begin to taper their daily doses after the second apheresis, and 3 of 5 of these patients reached the end of the study steroid-free. GMA apheresis was well tolerated and no severe side effects related to the technique were observed. Conclusions: GMA apheresis is a safe, well-tolerated technique in paediatric IBD. As previously reported, we have observed a better efficacy in promoting and maintaining remission, and reducing conventional drugs in patients with UC than in patients with CD.


Transplant International | 2010

Autoimmune cytopaenia after paediatric intestinal transplantation: a case series

Gonzalo Botija; Marta Ybarra; Esther Ramos; Manuel Molina; Jesús Sarría; Eva Martínez-Ojinaga; Ane M. Andres; Manuel López-Santamaría; Gerardo Prieto

Autoimmune cytopaenia is a rare, but severe complication after solid organ transplantation. We retrospectively analysed 57 paediatric intestinal transplants performed in 49 patients between 1999 and 2009. Autoimmune cytopaenia was observed in six patients; it appeared after an average of 10 months post‐transplant. Warm autoimmune haemolytic anaemia was developed in three patients, cold autoimmune haemolytic anaemia in one and two presented a mixed type. Incidence and causes for haematological cytopaenia such as the following were investigated: immunosuppression, major blood mismatch, viral infection, malignancy, passenger lymphocyte syndrome and lymphoproliferative disorders. Initial treatment included high‐dose steroids, intravenous immunoglobulin, plasmapheresis and maintenance of body temperature above 37 °C in those with cold autoantibodies. Inclusion of the spleen in multivisceral transplants seems to be an important risk factor. All patients, except one, relapsed after classic therapy, requiring additional treatments. Sirolimus conversion was performed in four patients. One died after infection. The immunosuppressive therapies associated with other concomitant factors, such as viral infections, lymphoproliferative disorders, graft‐versus‐host disease, passenger lymphocyte syndrome and the inclusion of the spleen as part of multivisceral graft seem to play an important part in the development of autoimmune processes after intestinal transplantation. Therapy is not well established, especially in those resistant to first‐line treatment.


Pediatric Transplantation | 2013

Post-transplant lymphoproliferative disorders and other malignancies after pediatric intestinal transplantation: incidence, clinical features and outcome.

Esther Ramos; Francisco Hernandez; Ane M. Andres; Eva Martínez-Ojinaga; Manuel Molina; Jesús Sarría; Manuel López-Santamaría; Gerardo Prieto

PTLDs are a well‐recognized and potentially fatal complication after intestinal transplantation. We analyzed the incidence, clinical features, and outcome in a 63 intestinal transplantation series performed in our unit between October 1999 and July 2011. Types of graft included ISB (n = 23), LSB (n = 20), and MV (n = 20). Patients were categorized into three groups of immunosuppression: I (n = 43) received basiliximab, tacrolimus, and steroids; II (n = 11) thymoglobulin and tacrolimus, and III (n = 9) alemtuzumab and tacrolimus. EBV status was serially assessed. All PTLD cases were biopsied to establish histopathological diagnosis. The incidence of PTLD was 14.2% (9/63). Median onset of PTLD after transplant was four months (range: 0.5–28), within first postoperative year in 6 (66.6%) patients. Fever was the most common symptom. Graft removal was needed in four patients (44%). The patient survival rate was 66.6% (6/9). We have not found any association between PTLD and immunosuppression regimen or transplant type. However, there was a statistical association with EBV active infection.


Journal of Pediatric Gastroenterology and Nutrition | 1990

Association of juvenile and adenomatous polyposis with pulmonary arteriovenous malformation and hypertrophic osteoarthropathy.

Gerardo Prieto; Isabel Polanco; J. Sarria; Javier Larrauri; Lassaletta L

The juvenile form is the usual type of colonic polyp seen during childhood. However, mixed forms associating juvenile and adenomatous polyps have been reported. A syndrome including the association of generalized juvenile polyposis, pulmonary arteriovenous malformation, and hypertrophic osteoarthropathy has been described in three cases; however, this is the first report of the association of mixed juvenile and adenomatous polyposis, pulmonary arteriovenous malformation, and hypertrophic osteoarthropathy.

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Manuel Molina

Hospital Universitario La Paz

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Esther Ramos

Hospital Universitario La Paz

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Francisco Hernandez

Hospital Universitario La Paz

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Juan A. Tovar

Hospital Universitario La Paz

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Jesús Sarría

Hospital Universitario La Paz

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Jose Luis Encinas

Hospital Universitario La Paz

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Ane M. Andres

Hospital Universitario La Paz

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Isabel Polanco

Autonomous University of Madrid

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Leopoldo Martinez

Hospital Universitario La Paz

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