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Biomedical subjects

Manuel Lopez

Publications and source records attributed to Manuel Lopez.

17 recordsLinked to original sources
PubMed2007

Multicenter assessment of ultrasound of the spermatic cord in children with acute scrotum.

PURPOSE: Intravaginal or extravaginal spermatic cord torsion is a diagnostic challenge for the surgeon and radiologist. Color Doppler sonography can be inaccurate, leading to dangerous false-negative results. To date, no single reliable test has been able to provide 100% diagnostic accuracy. The direct visualization of the twisted cord during emergency high resolution ultrasonography has been proposed to avoid systematic and abusive surgical exploration. The aim of this multicenter study was to assess the validity and reproducibility of high resolution ultrasonography based management of acute scrotum in children. MATERIALS AND METHODS: A total of 919 patients from 11 European university hospitals underwent color Doppler sonography and high resolution ultrasonography for acute scrotum between 1992 and 2005. The spermatic cord was studied along its complete length to detect a spiral twist. The surgical findings were correlated with the preoperative results. RESULTS: A total of 208 patients had spermatic cord torsion proved at surgery. Intratesticular vascularization was absent in the affected testis in only 158 cases (76%). In contrast, high resolution ultrasonography detected the twist as a snail shell-shaped mass, measuring 7 to 33 mm, in 199 patients (96%). High resolution ultrasonography revealed a linear cord for all other causes of acute scrotum (711 patients) with a specificity of 99%. The radiologist training level was the best predictive factor of high resolution ultrasonography reliability (p <0.05). CONCLUSIONS: High resolution ultrasonography based management of acute scrotum is reliable and reproducible. Thanks to its high sensitivity and specificity for the diagnosis of spermatic cord torsion, high resolution ultrasonography can significantly improve the management of acute scrotum in children.

Acute Disease↗
PubMed2006

Multicentric assessment of the safety of neonatal videosurgery.

BACKGROUND: Complex procedures for managing congenital abnormalities are reported to be feasible. However, neonatal videosurgery involves very specific physiologic constraints. This study evaluated the safety and complication rate of videosurgery during the first month of life and sought to determine both the risk factors of perioperative complications and the most recent trends in practice. METHODS: From 1993 to 2005, 218 neonates (mean age, 16 days; weight, 3,386 g) from seven European university hospitals were enrolled in a retrospective study. The surgical indications for laparoscopy (n = 204) and thoracoscopy (n = 14) were congenital abnormalities or exploratory procedures. RESULTS: Of the 16 surgical incidents that occurred (7.5%), mainly before 2001, 11 were minor (parietal hematoma, eventration). Three neonates had repeat surgery for incomplete treatment of pyloric stenosis. In two cases, the incidents were more threatening (duodenal wound, diaphragmatic artery injury), but without further consequences. No mortality is reported. The 26 anesthetic incidents (12%) that occurred during insufflation included desaturation (<80% despite 100% oxygen ventilation) (n = 8), transient hypotension requiring vascular expansion (n = 7), hypercapnia (>45 mmHg) (n = 5), hypothermia (<34.9 degrees C) (n = 4), and metabolic acidosis (n = 2). The insufflation had to be stopped in 7% of the cases (transiently in 9 cases, definitively in 6 cases). The significant risk factors for an incident (p < 0.05) were young age of the patient, low body temperature, thoracic insufflation, high pressure and flow of insufflation, and length of surgery. CONCLUSION: Despite advances in miniaturizing of instruments and growth in surgeons' experience, the morbidity of neonatal videosurgery is not negligible. A profile of the patient at risk for an insufflation-related incident emerged from this study and may help in the selection of neonates who will benefit most from these techniques in conditions of maximal safety.

Age Factors↗
PubMed2006

Thoracoscopy in pediatric pleural empyema: a prospective study of prognostic factors.

PURPOSE: The indications for thoracoscopy remain imprecise in cases of pleural empyema. This study aimed to identify preoperative prognostic factors to help in the surgical decision. METHODS: From 1996 to 2004, 50 children with parapneumonic pleural empyema underwent thoracoscopy either as the initial procedure (n = 26) or after failure of medical treatment (n = 24). Using multivariate analysis, we tested the prognostic value of clinical and bacteriological data, the ultrasonographic staging of empyema, and the delay before surgery. Outcome measures were technical difficulties, postoperative complications, time to apyrexia, duration of drainage, and length of hospitalization. RESULTS: The clinical and bacterial data did not significantly predict the postoperative course. Echogenicity and the presence of pleural loculations at ultrasonography were not independent significant prognostic factors. A delay between diagnosis and surgery of more than 4 days was significantly correlated (P < .05) with more frequent surgical difficulties, longer operative time, more postoperative fever, longer drainage time, longer hospitalization, and more postoperative complications, such as bronchopleural fistula, empyema relapse, and persistent atelectasia. CONCLUSION: The main prognostic factor for thoracoscopic treatment of pleural empyema is the interval between diagnosis and surgery. A 4-day limit, corresponding to the natural process of empyema organization, is significant. The assessment of loculations by ultrasonography alone is not sufficient to predict the postoperative course.

Bacterial Infections↗
PubMed2006

The transmanubrial approach: a new operative approach to cervicothoracic neuroblastoma in children.

BACKGROUND: Cervicothoracic neuroblastoma originates from the cervical sympathetic nerves and ganglia and thus presents a problem when dissecting the vascular and nervous elements of the subclavian region. The standard operation is based on thoracotomy or dual cervicotomy/thoracotomy, but these approaches do not provide optimal control of the subclavian vessels. We report our experience in children with cervicothoracic neuroblastoma by using a technique usually performed for apical lung cancer. METHODS: Four patients with localized cervicothoracic neuroblastoma with no N-myc amplification were resected after chemotherapy by this approach. The anatomic evaluation was performed preoperatively with angio-magnetic resonance imaging. This transmanubrial approach, performed through a manubrial L-shaped transection and first costal cartilage resection, affords excellent access to the subclavian region with safe control of the vessels and nerves and exposure of the first 4 thoracic intervertebral foramina. RESULTS: Removal of more than 90% of the tumor was possible in all cases. The postoperative course was uneventful in 3 cases, and the fourth patient with a left-sided tumor had a transient chylothorax. No recurrence occurred with a follow-up period of 8 to 32 months. CONCLUSIONS: The transmanubrial approach is an osteomuscular-sparing technique that seems particularly suitable for the treatment of these tumors, which require a resection that is as complete as possible to avoid postoperative chemotherapy and tumor relapse.

Cervical Vertebrae↗
PubMed2006

Poor ex vivo induction of T-cell responses to idiotype or tumor cell lysate-pulsed autologous dendritic cells in advanced pre-treated multiple myeloma.

This study evaluated the feasibility of using dendritic cells (DCs) to generate, ex vivo, anti-tumor cytotoxic T lymphocytes (CTL) in patients with stage III multiple myeloma (MM). Nucleated cells from eight patients who had received chemotherapy (three of whom had undergone autologous hemopoeitic stem cell transplantation) were collected by apheresis. Their monocytes were enriched using counter-current centrifugation, differentiated into DCs which were further co-cultured with autologous CD8 lymphocytes to induce CTL. The DCs were pulsed either with the idiotypic paraprotein (regarded as a tumor-specific antigen) or with autologous MM cell lysate before co-culture. Specific T-cell responses were measured in IFNgamma enzyme-linked immunospot and chromium release assays of autologous plasmocyte targets. A slight increase in IFNgamma secretion by T-cells was observed for two patients (DCs pulsed with idiotypic paraprotein for one, MM cell lysate for the other). No or weak specific lysis of plasmocyte targets was observed in the chromium release assays. In conclusion, the T-cell response to pulsed DCs was very weak or absent. There are clinical and technical reasons that could explain, in part, this lack of response.

Adult↗
PubMed2005

[Mesenchymal stem cells from human proximal femurs possess immunosuppressive activity].

OBJECTIVE: To evaluate whether mesenchymal stem cells (MSCs) obtained from human proximal femurs possess immunosuppressive effect so as to look for ideal bank of MSCs for clinical prophylaxis and treatment of graft versus host disease (GVHD). METHODS: Human marrows were collected from the proximal femurs of patients undergoing hip replacement to isolate MSCs. The puncture materials obtained from the iliac bone marrow of 12 healthy donors were used as controls. Peripheral blood lymphocytes (PBLs) were obtained from the peripheral blood of healthy persons. 1 x 10(5) PBLs were mixed with allogeneic PBLs radiated by 60 cobalt and put into the wells of a 96-well plate. MSCs of the concentrations of 1 x 10(5), 3 x 10(4), 1 x 10(4), and 3 x 10(3), were added into the culture fluid of the mixed PBLs to be co-cultivated for 5 days. 1 microCi/well [(3)H] TdR was added in the last 18 hours. The cells were collected and the counts per minute (cpm) was detected. 3 x 10(4) and 1 x 10(4) MSCs were put into the wells. When the MSCs adhered to the wall, a membrane with micropores was inserted value of 1 x 10(5) PBLs and radiated allo-PBLs were put onto the top of which. Five days after cultivation 1 microCi/well [(3)H] TdR was added and the cpm was tested. MSCs were cultured in RPMI-1640 culture fluid and then contacted MLR constructed by 1 x 10(5) PBLs and 1 x 10(5) allo-PBL directly or via Transwell membrane with micropores. Five days after the supernatant was collected. ELISA was used to detect the content of TGF-beta(1). 0.1 microg/ml, 1 microg/ml, or 10 microg/ml anti-human TGF-beta1 antibody was added to the co-cultivation system. Five days after [(3)H] TdR was added so as to test the value cpm. RESULTS: 3 x 10(3) - 1 x 10(5) MSCs from proximal femurs inhibited the PBLs proliferation to 62 +/- 18% - 28 +/- 12% of maximal response, however, not significantly different from that observed in MSCs collected from bone marrow of healthy donors via iliac crest aspiration (58 +/- 12% - 27 +/- 6%, P > 0.05). When these cells were separated physically from MLR system via a membrane with micropores 0.2 microm in diameter, 3 x 10(4) and 1 x 10(4) cells still markedly suppressed the PBLs proliferation to 36 +/- 8% and 53 +/- 13% of maximal response. ELISA showed that TGF-beta1 was measured in the supernatants of MSCs, MSCs + MLR and MSCs + MLR in Transwell system, without significant differences among these experimental conditions. Furthermore, the presence of increasing amounts of neutralizing anti- TGF-beta1 antibody did not reverse the inhibitory effect. CONCLUSION: MSCs obtained from the proximal femurs possess immunosuppressive activity. A soluble factor/factors was/were involved in such effect, however, TGF-beta1 was not a candidate.

Adult↗
PubMed2005

An early thoracoscopic approach in necrotizing pneumonia in children: a report of three cases.

INTRODUCTION: Cavitary necrosis remains a rare complication of bacterial pneumonia in children. Conservative medical treatment and radical surgical treatment with lung resection are the current therapeutic choices. Evaluation of thoracoscopy for this pathology has not yet been reported. We describe 3 cases. MATERIALS AND METHODS: Between January 2001 and January 2002, 3 children (1, 2, and 3 years old) were admitted to our institution with necrotizing pneumonia. The diagnosis was based on injected computed tomography (CT) scan showing pulmonary condensation, intra-parenchymal bullae, and hypovascularization. In addition to an adapted antibiotic therapy, a thoracoscopic approach was decided on within 24 hours of diagnosis, with extensive decortication, ablation of superficial necrotic debris, irrigation, and drainage. RESULTS: No conversion to open thoracotomy or lung resection was needed. Admission to the intensive care unit was unnecessary. On average, apyrexia was reached on postoperative day (POD) 2 and tube drainage was removed on POD 15. Mean follow-up at 16 months showed excellent lung re-expansion with no relapse. CONCLUSION: On the condition that the decision is made quickly, thoracoscopy may be a valuable treatment option in childhood necrotizing pneumonia, as it hastens recovery and avoids lung resection. Injected CT scan allows an early diagnosis and we propose the first 24 hours after diagnosis as the optimal period for thoracoscopy because of the rapid natural course of lung gangrene.

Child, Preschool↗
PubMed2005

Tolerance of laparoscopy and thoracoscopy in neonates.

OBJECTIVES: Video-surgery in neonates is recent. Data on the respiratory, hemodynamic, and thermic effects during the first month of life are still sparse. This study aimed to evaluate the tolerance of video-surgery in neonates and to determine the risk factors of per-operative complications. METHODS: From 1994 to 2004, 49 neonates (mean age: 11 days; weight: 3285 g) underwent 50 video-surgical procedures. Indications for laparoscopy were duodenal atresias, volvulus with malrotation, pyloric stenosis, gastroesophageal reflux, cystic lymphangiomas, ovarian cysts, biliary atresia, and congenital diaphragmatic hernias; indications for thoracoscopy were esophageal atresias and tracheoesophageal fistula. RESULTS: Median operative time was 79 minutes. Mean insufflation pressure was 6.7 mm Hg (range: 3-13). Oxygen saturation decreased, especially with thoracic insufflation or high-pressure pneumoperitoneum. Systolic arterial pressure, which decreased in 20% of the patients, was controlled easily with vascular expansion. Thermic loss (mean postoperative temperature: 35.6 degrees C) was proportional to the duration of insufflation. No surgical incident was noted. Ten anesthetic incidents occurred (20%), 3 of which required temporary or definitive interruption of insufflation (O2 saturation <70%). Risk factors for an incident were low preoperative temperature, high variation of end-tidal pressure of CO2, surgical time >100 minutes, thoracic insufflation, and a high oxygen or vascular expansion requirement at the beginning of insufflation. CONCLUSION: The neonate's high sensitivity to insufflation is an important limiting factor of video-surgery. The described profile of the neonate at risk may help to reduce the frequency of adverse effects of this technique and improve its tolerance.

Blood Pressure↗
PubMed2004

Homing of in vitro expanded Stro-1- or Stro-1+ human mesenchymal stem cells into the NOD/SCID mouse and their role in supporting human CD34 cell engraftment.

The Stro-1 antigen potentially defines a mesenchymal stem cell (MSC) progenitor subset. We here report on the role of human ex vivo-expanded selected Stro-1(+) or Stro-1(-) MSC subsets on the engraftment of human CD34(+) cord blood cells in the nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mouse model. The data show that cotransplantation of expanded Stro-1(-) cells with CD34(+) cells resulted in a significant increase of human CD45, CD34, CD19, and CD11b cells detected in blood or in bone marrow (BM) and spleen as compared with the infusion of CD34(+) cells alone. Infusion into mice of expanded Stro-1(+) and Stro-1(-) cells (without CD34(+) cells) showed that the numbers of Stro-1(+)-derived (as assessed by DNA analysis of human beta-globin with quantitative polymerase chain reaction [PCR]) were higher than Stro-1(-)-derived cells in spleen, muscles, BM, and kidneys, while more Stro-1(-)-derived than Stro-1(+)-derived cells were found in lungs. The transduction of expanded Stro-1(+) cells with an enhanced green fluorescent protein (eGFP) gene did not modify their cytokine release and their homing in NOD/SCID mouse tissues. The difference between the hematopoietic support and the homing capabilities of expanded Stro-1(+) and Stro-1(-) cells may be of importance for clinical therapeutic applications: Stro-1(+) cells may rather be used for gene delivery in tissues while Stro-1(-) cells may rather be used to support hematopoietic engraftment.

Animals↗
PubMed2003

Monitoring of residual hematopoiesis after total body irradiation in humans as a model for accidental x-ray exposure: dose-effect and failure of ex vivo expansion of residual stem cells in view of autografting.

PURPOSE: To evaluate the residual hematopoiesis at different levels of total body irradiation (TBI) dose in bone marrow (BM) and peripheral blood (PB), and to study the dose-effect relationship on hematopoietic immature and mature progenitors. We also investigated the possibility of expanding ex vivo the residual progenitors exposed to different dose levels of TBI. METHODS AND MATERIALS: Eight patients treated for AML (n = 3) and myeloma (n = 5) were included. BM and PB samples were harvested before TBI and after doses of: 5 Gy. Mononuclear cells (MNCs) were assayed for burst-forming unit erythroid (BFU-E), granulocyte-forming unit macrophage (CFU-GM), and long-term culture initiating cells (LTC-ICs). Ex vivo expansion: MNCs (after irradiation and controls) were suspended in long-term cultures and expanded with a combination of five cytokines. RESULTS: CD34+ cells were detectable at 10 Gy. We observed a significant decrease of CFU-GM and BFU-E, respectively, to 13.5% and 8.5% of baseline values for doses <or=2 Gy and to 8.2% and 4.6% for doses ranging between 2.1 and 5 Gy. No dose effect was observed for residual MNCs. LTC-ICs were not detectable after 0.8 Gy. The expansion was not successful after 1.2 Gy. CONCLUSION: This study confirms the significant decrease of human mature and immature progenitors in BM and PB immediately after low-dose TBI. In addition, the lack of expansion suggests that autografting using BM or PB residual stem cells collected and expanded in vitro in case of accidental whole body exposure may be impractical.

Adult↗
PubMed2003

Occupational asthma caused by high-molecular-weight substances.

More than 250 agents that are encountered in the workplace have been shown to induce asthma in susceptible individuals. It is estimated that 2% to 15% of cases of asthma may be occupational. High-molecular-weight substances, such as plant and animal proteins, enzymes, and large carbohydrate molecules, can induce IgE-mediated occupational asthma. The incidence of disease varies among industries and is dependent on the physiochemical properties of the agent, the level and duration of exposure, industrial hygiene, engineering practices, and host factors. Risk factors, common high-molecular-weight workplace antigens, diagnosis, treatment, and prognosis are discussed.

Asthma↗
PubMed2002

Reinjection of ex vivo-expanded primate bone marrow mononuclear cells strongly reduces radiation-induced aplasia.

To assess the therapeutic efficacy of ex vivo-expanded hematopoietic cells in the treatment of radiation-induced pancytopenia, we have set up a non-human primate model. Two ex vivo expansion protocols for bone marrow mononuclear cells (BMMNC) were studied. The first consisted of a 7-day culture in the presence of stem cell factor (SCF), Flt3-ligand, thrombopoietin (TPO), interleukin-3 (IL-3), and IL-6, which induced preferentially the expansion of immature hematopoietic cells [3.1 +/- 1.4, 10.0 +/- 5.1, 2.2 +/- 1.9, and 1.0 +/- 0.3-fold expansion for mononuclear cells (MNC), colony-forming units-granulocyte-macrophage (CFU-GM), burst-forming units erythroid (BFU-E), and long-term culture initiating cells (LTC-IC) respectively]. The second was with the same cytokine combination supplemented with granulocyte colony-stimulating factor (G-CSF) with an increased duration of culture up to 14 days and induced mainly the production of mature hematopoietic cells (17.2 +/- 11.7-fold expansion for MNC and no detectable BFU-E and LTC-IC), although expansion of CFU-GM (13.7 +/- 18.8-fold) and CD34+ cells (5.2 +/- 1.4-fold) was also observed. Results showed the presence of mesenchymal stem cells and cells from the lymphoid and the megakaryocytic lineages in 7-day expanded BMMNC. To test the ability of ex vivo-expanded cells to sustain hematopoietic recovery after radiation-induced aplasia, non-human primates were irradiated at a supralethal dose of 8 Gy and received the product of either 7-day (24 h after irradiation) or 14-day (8 days after irradiation) expanded BMMNC. Results showed that the 7-day ex vivo-expanded BMMNC shortened the period and the severity of pancytopenia and improved hematopoietic recovery, while the 14 day ex vivo-expanded BMMNC mainly produced a transfusion-like effect during 8 days, followed by hematopoietic recovery. These results suggest that ex vivo expanded BMMNC during 7 days may be highly efficient in the treatment of radiation-induced aplasia.

Animals↗
PubMed2002

Intrapleural infusion of activated macrophages and gamma-interferon in malignant pleural mesothelioma: a phase II study.

STUDY OBJECTIVES: Intrapleural immunotherapy has shown some activity in patients with malignant mesothelioma. We conducted a multicentric pilot phase II study to evaluate the tolerance and the activity of intrapleurally infused autologous human activated macrophages (AM Phi) in patients with stage IA, IB, and IIA malignant pleural mesothelioma (MPM). DESIGN: AM Phi derived from in vitro monocyte culture were infused into the pleura of patients every week for 8 consecutive weeks. Each infusion was followed 3 days later by an intrapleural injection of 9 millions units of gamma-interferon (gamma-IFN) in an attempt to prolong the in vivo activation of infused AM Phi. Response was assessed by CT scan and thoracoscopy when possible. If the patient's disease progressed after AM Phi treatment, an additional treatment was left to the choice of the investigator. PATIENTS: Nineteen patients with histologically proven stage IA, IB, or IIA MPM were enrolled. Two patients were excluded before any AM Phi infusion because of complications impeding infusion. Seventeen patients were actually treated. After completion of the AM Phi cellular therapy, 10 patients were treated with chemotherapy as their diseases progressed. RESULTS: The overall response rate of patients actually treated was 14%. When including the two patients enrolled but not treated, the overall response "in intention to treat" was 11%; two patients had a partial response, with a duration of response of 30 months and 3 months, respectively. One patient, who could not be evaluated by thoracoscopy because of pleural symphysis, is still alive without any clinical or radiologic sign of disease 69 months after treatment. No major adverse effects were observed during the infusion of either AM Phi or gamma-IFN, and there was no interruption of treatment because of toxicity. However, symphysis was observed in 7 of 14 patients who received the complete treatment. The median survival of patients actually treated, including those who received chemotherapy after AM Phi, was 29.2 months. CONCLUSION: Combined infusion of AM Phi and gamma-IFN was well tolerated in patients with MPM; however, it had limited antitumor activity.

Aged↗
PubMed2000

Cryopreservation of Dendritic Cells Grown in Vitro from Monocytes for Their Future Clinical Use.

Dendritic cells are professional antigen presenting cells which are being used as adjuvants in tumor vaccination trials. Most clinical protocols currently include 4 to 10 weekly infusions of doses > 10(6) cells, each inoculum coming from a simple culture of blood monocytes. In the present study, several millions of dendritic cells from a single leukapheresis were produced; monocytes were isolated by elutriation and then cultured in Teflon bags in presence of 800 U/ml GM-CSF + 100 micro g/ml IL-13 + 10% fetal calf serum (FCS). The dendritic cells from this single batch were aliquoted in many doses for potential multiple infusions and cryopreserved in 10% DMSO + 2% human albumin in Teflon-kapton Fresenius bags either at -1 degrees C/min using a controlled rate freezer, or putting the bags directly in a -80 degrees C mechanical freezer without controlling the temperature rate. Six experiments were carried out. After one month of cryopreservation, the cells were thawed in a 40 degrees C water bath. Before and after freezing, cells were evaluated for immunophenotype (CD1a, CD14, CD40, CD80, CD83, CD86, CD54, CD58, CD16, CD32, CD64 and HLA-DR) and for their capacity to stimulate allogenic (MLR) or autologous (antigen presentation tests) lymphocytes. The results demonstrated that the mean recovery rates after freezing in liquid nitrogen or at -80 degrees C were (67 +/- 14)% and (71 +/- 13)% respectively, without any significant difference between the two techniques. The immunophenotype was not modified by the freezing-thawing procedure, as well as the lymphocyte stimulating capacities. In conclusion, our study showed that substantial numbers of functional DCs can be derived from peripheral blood monocytes using Teflon bags. DCs can be cryopreserved in a good laboratory practice setting for further clinical trials with an acceptable loss of cells and without modification of their functions.

Journal Article↗
PubMedDate not supplied

Effects of air pollutants on the allergic response.

There is strong evidence that the prevalence and severity of allergy are increasing in many areas of the world. Pollutants have been implicated as one of the important factors responsible for these observations because they have been shown to act at multiple steps in the allergic response. They can increase immunoglobulin E (IgE) synthesis and potentiate the specific IgE response to antigens. Pollutants also are capable of inducing a primary specific IgE response to an antigen and increase allergic airway inflammation. In addition, pollutants can induce airway inflammation or cause nonspecific irritation. Pollutants also are capable of modulating the allergenicity of airborne substances, which possibly may promote allergic sensitization.

Air Pollutants↗