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J Michon

Publications and source records attributed to J Michon.

At least 73 records · Page 4Linked to original sources

Generation and characterization of a mouse single-chain antibody fragment specific for disialoganglioside (GD2).

Anti-disialoganglioside (GD2) monoclonal antibodies (MAbs) have been used in vivo for immunolocalization and in phase I and II trials to target disseminated neuroblastoma, the most common extracranial solid tumor in children. However, the efficacy of these first-generation MAbs is likely to be improved by using engineered anti-GD2 antibodies. The generation of single-chain antibody fragments (scFv) could be very helpful as these molecules can be further modified to produce recombinant molecules with pre-defined properties such as immunotoxins, chimeric, or bispecific antibodies. Thus, a scFv directed against GD2 (scFv 7A4) was cloned, sequenced, and expressed. Its binding properties were characterized and compared to that of the parental MAb 7A4. Nucleotide sequence analysis of the scFv 7A4 indicated that its VH region belongs to the V region IIID subgroup and the V kappa to the V region II subgroup. The scFv 7A4 bound to GD2+ neuroblastoma cell lines but not to GD2- cell lines or to GD2- cells isolated from peripheral blood. ELISA and thin-layer chromatography (TLC) indicated that it retained the anti-GD2 specificity, and exhibited a slight cross-reaction with GD3 as the parental MAb. This scFv makes it possible to develop new useful reagents through genetic engineering for adjuvant tumor therapy.

Amino Acid Sequence↗

NB87 induction protocol for stage 4 neuroblastoma in children over 1 year of age: a report from the French Society of Pediatric Oncology.

PURPOSE: NB87 was designed to test the efficacy of a short, non cross-resistant, induction protocol for unselected patients over 1 year of age with stage 4 neuroblastoma. A secondary objective was to compare in a randomized study the toxicity of two modalities of cisplatin administration. PATIENTS AND METHODS: A total of 183 patients received two cycles of alternating sequences: cyclophosphamide 300 mg/m2/d on days 1 to 5, vincristine 1.5 mg/m2/d on days 1 and 5, and doxorubicin 60 mg/m2/d on day 5 (CADO); and cisplatin 40 mg/m2/d and etoposide 100 mg/m2/d on days 1 to 5 (CVP), followed by surgery of the primary tumor (126 patients). Ninety-one were randomized to receive cisplatin either as bolus (BO; n = 48) or continuous infusion (CI; n = 43). International Neuroblastoma Staging System (INSS) and Response Criteria (INRC) were used with emphasis on skeletal evaluation by meta-iodobenzylguanidine (MIBG). RESULTS: Hematotoxicity was predominant, with a higher incidence of neutropenia (P = .01) for CADO and of thrombocytopenia for CVP (P < .001). Severe infections, as well as nonhematologic toxicities, occurred more often after the first sequence. Gastrointestinal complications were predominant during both courses of CVP. The toxic death rate, including surgery, was 3%. Complete remissions (CRs) were less frequent on MIBG (45%) compared with marrow (66%) or other metastases (61%). Combining all metastatic sites resulted in a 39% CR rate. After surgery, the final CR rate was 42%. Nephrotoxicity was minimal in both arms (92% normal clearance for CI v 82% for BO). Hearing loss greater than 40 dB at 6,000 to 8,000 Hz was reported equally in both arms (n = 6 for CI v n = 5 for BO). CONCLUSION: Intensified chemotherapy using CADO/CVP increases CR rates despite a shorter induction duration. However, the rate of MIBG normalization remains unsatisfactory and could be raised through the dose-intensive use of agents such as cyclophosphamide.

Adolescent↗

N-Myc gene amplification is a major prognostic factor in localized neuroblastoma: results of the French NBL 90 study. Neuroblastoma Study Group of the Société Francaise d'Oncologie Pédiatrique.

PURPOSE: To assess the relevance of N-Myc gene amplification (NMA) as a prognostic factor in localized neuroblastoma (NB) and to evaluate whether less intensive adjuvant treatment is advisable in infants without NMA. PATIENTS AND METHODS: Assessment of NBs included clinical and imaging data to allow tumor-node-metastasis (TNM) staging, biologic determinations (N-Myc gene analysis), and standard histology and work-up to eliminate metastatic spread (metaiodobenzylguanidine [MIBG] scintigraphy and extensive bone marrow staging). Resectability was defined according to imaging findings. Chemotherapy was indicated in children older than 1 year at diagnosis who had postoperative residual disease or lymph node (LN) involvement, in infants with NMA, or as primary treatment in children with an unresectable NB, including dumbbell tumors. Radiotherapy was recommended in children older than 1 who presented with persistent gross residual disease at the end of therapy. RESULTS: Between 1990 and 1994, 316 consecutive children who presented with a localized NB were registered in the NBL 90 study. The median age was 12 months, and 42 patients had dumbbell tumors (13%). NMA was found in 22 of 225 assessable children (10%) and correlated with adverse prognostic indicators such as age older than 1 year, an abdominal primary tumor, a large tumor (T3), and unresectability. Among 186 children who had primary excision, five died of surgery-related complications. Primary chemotherapy was given to 130 patients, which allowed removal of the tumor in all but four. The 5-year overall survival (OS) and event-free survival (EFS) rates were, respectively, 91% and 84% with a median follow-up time of 36 months. The outcome of infants and older children was similar (P = .2). EFS of patients with resectable tumors was slightly better than with unresectable primary tumors (EFS, 89% v 78%; P = .02). In dumbbell NBs, neurologic recovery was achieved in 74% of cases that presented with symptoms, and initial laminectomy was avoided in 75% of children. In a univariate analysis, large tumors, high neuron-specific enolase (NSE) and lactate dehydrogenase (LDH) levels, positive LNs, macroscopic residue, and NMA adversely influenced outcome. In the multivariate analysis, NMA was the most powerful unfavorable predictive indicator: OS and EFS rates for these children were 36% and 32%, compared with 98% and 90% in nonamplified tumors (P < .001). CONCLUSION: Our data confirm the overall good prognosis of localized NBs, even when unresectable. NMA is the most relevant adverse prognostic factor in localized NBs, and more intensive treatment should be investigated in these patients. Prospective studies of other biologic factors are warranted to tailor therapy more accurately. The EFS of children who underwent primary surgery was excellent, and further justifies elimination of adjuvant treatment provided they have no NMA. Despite the elimination of postoperative therapy, infants with non-NMA tumors have an excellent outcome, which suggests that initial chemotherapy can be further reduced in case of unresectable NBs.

Adolescent↗

Fc receptors as targets for immunotherapy.

Human membrane and soluble Fc epsilon receptors (Fc epsilon RI, Fc epsilon RII/CD23) and Fc gamma receptors (Fc gamma RI/CD64, Fc gamma RII/CD32, Fc gamma RIII/CD16) have been implicated in a number of diseases. Their functional roles such as capture and clearance of immune complexes, antibody-dependent cell cytotoxicity, or cytokine or inflammatory mediator release, make them potential targets for immuno-intervention. In the present review, we will describe how membrane and soluble human Fc epsilon R and Fc gamma R have been already used as targets/tools for immuno-interventions by using monoclonal and bispecific engineered antibodies. Some therapeutic uses of these molecules both in cancer, infectious, and auto-immune diseases are presented.

Humans↗

The treatment of neuroblastoma with intraspinal extension with chemotherapy followed by surgical removal of residual disease. A prospective study of 42 patients--results of the NBL 90 Study of the French Society of Pediatric Oncology.

BACKGROUND: Neuroblastoma is the most common malignant cause of spinal compression in the pediatric population. More than 30% of patients who are impaired prior to treatment remain impaired after the completion of therapy. Those who do not improve after decompressive laminectomy may go on to develop severe delayed spinal deformities. METHODS: To decrease the long term sequelae of routine neurosurgical intervention for all intraspinal extensions of neuroblastoma, the French NBL 90 Study was formulated to use chemotherapy as a first-line treatment for all nonmetastatic neuroblastomas with intraspinal extension. Neurosurgical decompression and excision was recommended only for patients demonstrating rapid neurologic deterioration. RESULTS: The overall survival of the 42 patients registered was 97%. Initial neurologic impairment was present in 27 patients (64%), including 11 with paraplegia. Thirty-two patients received chemotherapy as first-line treatment. Complete regression of the intraspinal component was observed in 13 patients and partial regression of greater than 50% of the initial volume in 5 patients. Of 19 evaluable patients presenting with a neurologic deficit and treated with primary chemotherapy, recovery was completed in 11 and partial in 3. Four patients failed to recover from long-standing pretreatment paraplegia. Only one patient worsened during therapy, and recovered completely after emergent neurosurgical intervention. Seven patients underwent initial neurosurgical procedures; six had a neurologic deficit and five recovered completely, including all three who presented with acute onset of paraplegia. Three patients had extraspinal surgery as exclusive treatment. Six patients (15%) suffered severe neurologic sequelae. Only one of the patients who underwent surgery required spinal stabilization for progressive deformity, but follow-up is limited. CONCLUSIONS: By treating patients with dumbbell neuroblastoma initially with chemotherapy, the authors were able to reduce the size of the intraspinal mass in 58% of patients, improve partial neurologic deficits in 92%, and avoid neurosurgical decompression in 60%. Neurologic deficits also improved in 83% of patients requiring emergent neurosurgical intervention.

Adolescent↗

Clinical relevance of loss heterozygosity of the short arm of chromosome 1 in neuroblastoma: a single-institution study.

Neuroblastoma is characterized by a wide variability of its clinical course, and considerable effort has been made to identify factors determining outcome in this disease. In a series of 82 patients from a single institution, we have investigated the prognostic impact of multiple clinical, biological and genetic parameters. Univariate testing showed that advanced stage of disease, abdominal localization of the primary tumor, elevated urinary dopamine levels, N-myc amplification (NMA) and loss of heterozygosity of chromosome lp (LOH lp) were related to a poor outcome. Most of these parameters were strong indicators of treatment failure in children younger than 12 months of age but none of them, apart from stage, had a significant prognostic impact in patients older than 12 months at diagnosis. Interestingly, the shorter survival time associated with the presence of lp deletions or NMA appears to be more strongly linked to a poorer outcome after relapse or progression than to a shorter progression-free interval. Although different types of LOH lp have been described in neuroblastoma and may be associated with different biological features, as suggested by a different pattern of catecholamine secretion, tumors with LOH lp present an aggressive clinical behavior, regardless of the type of LOH lp. In this study, LOH lp is an indicator of poor prognosis and identifies a larger population at risk than NMA alone.

Chromosomes, Human, Pair 1↗

Histopathologic risk factors in retinoblastoma: a retrospective study of 172 patients treated in a single institution.

BACKGROUND: Microscopic extrascleral involvement and involvement of optic nerve resection line are accepted risk factors for orbital and/or metastatic disease from retinoblastoma. Conversely, choroidal and retrolaminar optic nerve involvement are questionable risk factors. The aim of this retrospective study was to define the histopathologic risk factors for orbital and/or metastatic disease in patients treated by first-line enucleation. METHODS: Histopathologic review of 172 evaluable patients treated at Institut Curie between 1977 and 1990 determined the degree of choroidal (minimal or massive), scleral (intra- or extrascleral), optic nerve (prelaminar, retrolaminar with or without resection line involvement), and anterior chamber invasion. The degree of differentiation was also analyzed. The log rank test was used for univariate analysis and the Cox regression model was used for multivariate analysis. RESULTS. Eighty-seven percent of the 172 patients were disease free at 3 years. Twenty-three patients developed retinoblastoma recurrence. The disease-free survival was significantly different among the five subgroups of choroidal or scleral invasion (P = 3 x 10(-3). The differences among the four subgroups of optic nerve invasion were also significant (P = 10(-4)). Classical factors were confirmed in our series (extrascleral involvement and involvement of optic nerve resection line). Multivariate analysis of the 149 patients without these classical risk factors revealed two factors that increase the risk of orbital and/or metastatic disease: massive choroidal invasion and postlaminar optic nerve involvement. CONCLUSIONS: In our experience, retrolaminar optic nerve involvement, with free resection line, and massive choroidal invasion significantly increase the risk for orbital and/or metastatic disease.

Adolescent↗

The effect of somatostatin versus corticosteroid in the treatment of Graves' ophthalmopathy.

Uncontrolled study has demonstrated the usefulness of somatostatin in the treatment of mild Graves' ophthalmopathy (GO). We performed a prospective study to evaluate the usefulness of somatostatin as compared to corticosteroid in the treatment of moderately severe GO. All patients were rendered euthyroid and observed for 3 months to exclude spontaneous improvement without active treatment. They were randomized to receive either somatostatin (SS, octreotide 200 micrograms q8h subcutaneously, n = 8) or corticosteroid (CS, prednisone 1 mg/kg/day in decreasing doses, n = 10). Assessments of soft tissue inflammation, exophthalmos, palpebral aperture, intraocular pressure, diplopia, cornea, and visual acuity were made every 4 weeks for 3 months. MRI of the orbit was performed before and after treatment. Both SS and CS therapy decreased the palpebral aperture and activity score after 3 months (p < 0.05), but those treated with CS had a lower activity score after treatment when compared to SS [2.5 (1-7) v.s. 3.5 (0-4), median (range), p < 0.05]. Only CS, but not SS, was able to reduce intraocular pressure and muscle size as documented by MRI, but no significant reduction in proptosis was observed in either group. Also, patients' self-assessments of the eye changes after treatment were similar between the two groups. Both groups showed significant elevation of urinary glycosaminoglycan (GAG) excretion before therapy (SS 24.6 +/- 10.8; CS 27.8 +/- 11.4 mg/24 h), which was reduced after treatment (SS 12.5 +/- 7.3; CS 10.8 +/- 6.3 mg/24 h, p < 0.05). However, no significant correlation could be observed between the degree of GAG reduction and the clinical outcome of the patients. In conclusion, the long acting SS octreotide was effective in reducing soft tissue inflammation and providing symptomatic relief in GO but not as effective as corticosteroid in reducing muscle size. In view of the minimal side-effects and similar efficacy as compared to corticosteroid in patients with minimal extraocular muscle enlargement, it is suggested that a trial of SS may be considered in selected patients with GO.

Adult↗

Could somatostatin scintigraphy be superior to MIBG scan in the staging of stage IVs neuroblastoma (Pepper's syndrome)?

A 4-month-old infant suffering from Stage IVs neuroblastoma (NB IVs; Pepper's syndrome) was repeatedly examined by I-123 MIBG and somatostatin analog in-111 pentetreotide (SMS) scintigraphy, during a 2-year period. Treatment was restricted to surgery of the primary tumor. I-123 MIBG and SMS scan results were positive in the primary tumor and liver, but I-123 MIBG yielded very poor images and failed to reliably detect bone marrow metastases in the lower limbs and skull, whereas SMS precisely visualized these lesions. Six months after diagnosis, the infant was in complete clinical remission. I-123 MIBG and SMS images had returned to normal at 1 year. The prognostic implication of positive SMS imaging, in combination with positive or negative I-123 MIBG scan results, is not known in NB IVs and requires further investigation.

3-Iodobenzylguanidine↗

Galeal flap: clinical application in periorbital and orbital reconstruction.

We report the use of a galea flap in the reconstruction of the orbit and the periorbital in region three representative cases. Two patients, who had communication between the orbit, paranasal sinuses, and cranium following orbital and periorbital tumor resection, required a physical barrier to partition these compartments and an immunological barrier to prevent infection. A third patient, who had a contracted socket and had been on systemic steroids chronically, required a tissue with intrinsic blood supply to sustain an implant and promote healing. The outcome in all three patients was gratifying. The surgical anatomy is reviewed, the surgical technique detailed, and potential applications and complications discussed.

Adult↗

In vitro killing of neuroblastoma cells by neutrophils derived from granulocyte colony-stimulating factor-treated cancer patients using an anti-disialoganglioside/anti-Fc gamma RI bispecific antibody.

Neutrophils isolated from cancer patients treated with granulocyte colony-stimulating factor (G-CSF) express high levels of Fc gamma RI. They exhibited an efficient killing of GD2+ neuroblastoma cells in the presence of an antidisialoganglioside (GD2) mouse monoclonal antibody (MoAb; 7A4, IgG3 kappa). However, this cytotoxicity was totally blocked by human monomeric IgG. In contrast, a bispecific antibody (7A4 bis 22/MDX-260), prepared by chemically linking an F(ab') fragment of 7A4 with an F(ab') fragment of an anti-Fc gamma RI MoAb, 22, which binds outside the Fc binding domain, triggered antibody-dependent cell cytotoxicity, even when neutrophils were preincubated with human monomeric IgG. F(ab')2 22 MoAb abrogated the MDX-260 killing without affecting that of 7A4. The 3G8 MoAb, directed against the Fc gamma RIII binding site, did not inhibit the cytotoxicity induced by either antibody. Thus, these results indicate that G-CSF-activated neutrophils exert their cytotoxic effect against neuroblastoma cells through Fc gamma RI and not Fc gamma RIII, and that the saturation of the high affinity Fc gamma RI by monomeric IgG can be overcome by the use of bispecific antibodies binding epitopes outside the IgG Fc gamma RI binding site. A combined administration of such bispecific antibodies and G-CSF may be, therefore, an efficient therapeutic approach to trigger tumor lysis by cytotoxic neutrophils in vivo.

Antibodies, Bispecific↗

A new 123I-MIBG whole body scan scoring method--application to the prediction of the response of metastases to induction chemotherapy in stage IV neuroblastoma.

A new semi-quantitative scoring system is proposed, especially designed for the comparative interpretation of sequential whole-body meta-iodo-benzyl-guanidine (MIBG) scans in stage IV neuroblastoma children. This method was applied to assess whether MIBG scan at mid-course of induction chemotherapy could predict the final response. 27 newly diagnosed children were investigated by three sequential 123I-MIBG scans performed at the beginning, at mid-course (6 weeks) and at the end of neoadjuvant chemotherapy (12 weeks). Whole body scans were divided into nine regions in which the extension of bone metastases was separately quoted (score range: 0-3). The overall absolute scores were obtained by adding the scores of the nine regions. Relative scores were calculated by dividing the absolute score at each time by the corresponding pretreatment score. The score at mid-induction correctly predicted the overall response of metastases at the end of induction (P < 0.0001) in most cases. This method is easy to use, reproducible, subject to little inter-investigator variation, and thus well adapted to multicentric trials.

3-Iodobenzylguanidine↗

A multiplex PCR assay for routine evaluation of deletion of the short arm of chromosome 1 in neuroblastoma.

Deletions of the short arm of chromosome 1 (1p) are frequent alterations in neuroblastoma. Although a consensus region of deletion has been mapped to chromosome subband 1p36, recent studies suggest that several distinct loci on this chromosome may be involved in neuroblastoma. Moreover, different patterns of deletion might be associated with different clinical and biological characteristics of the tumours. These findings emphasise the importance of assessing the localisation and the extent of the deletions in neuroblastoma. We developed a technique which allows analysis of loss of heterozygosity at multiple loci on 1p in a single step, making use of a multiplex PCR method. Primers specific for six microsatellite loci mapped in the different regions of interest on 1p were used for simultaneous amplification of DNA, and loss of heterozygosity was determined after separation of the alleles by denaturing polyacrylamide gel electrophoresis. This technique enables a simple analysis of the position and extent of 1p deletions, and can be used for routine evaluation of 1p status in neuroblastoma.

Chromosome Deletion↗

In vivo targeting of human neuroblastoma xenograft by anti-GD2/anti-Fc gamma RI (CD64) bispecific antibody.

Antidisialoganglioside (GD2) monoclonal antibodies can target in vitro and in vivo neuroblastoma cells. However, their in vivo use is limited by the presence of high levels of circulating IgG which hamper the recruitment of effector cells through the high affinity Fc gamma RI (CD64). A bispecific Fab' x Fab' antiGD2/antiFc gamma RI antibody (7A4 bis 22), which binds outside the IgG binding site of Fc gamma RI, was therefore developed. This antibody binds both human GD2+ neuroblastoma and Fc gamma RI+ activated macrophages in vitro. It can localise a GD2 positive neuroblastoma xenografted on Nu/Nu mice. Scintigraphy tumour/muscle ratios showed that targeting with this antibody has an excellent selectivity for the tumour over normal tissues. Furthermore, although its whole body clearance is more rapid than that of the 7A4 parental antibody over the first 48 h, its selective tumour uptake is similar, as shown by immunoscintigraphy imaging. Thus, such a bispecific antibody may represent an efficient tool for in vivo therapy of neuroblastoma through its ability to recruit Fc gamma RI+ effector cells even in presence of circulating IgG and to bind concomitantly GD2+ tumour cells.

Animals↗

Measurement of the subarachnoid pressure of the optic nerve in human subjects.

PURPOSE: We measured the subarachnoid pressure of the optic nerve in 16 patients scheduled for ocular enucleation or evisceration. METHODS: We measured the subarachnoid pressure of the optic nerve directly with an electronic digital manometer in 16 patients scheduled for enucleation or evisceration for various blinding conditions. The nerve was exposed via a medial orbitotomy, and the subarachnoid pressure of the optic nerve was measured 5 mm posterior to the optic nerve head. The subarachnoid pressure of the optic nerve was also measured in five patients who were placed in the Trendelenburg position (head declined at a 30-degree angle) for three minutes. RESULTS: The subarachnoid pressure of the optic nerve varied from 4 to 14 mm Hg in the 16 patients tested. The mean subarachnoid pressure of the optic nerve was 8.5 mm Hg in the 16 patients tested. An increase of 1 to 2 mm Hg in the subarachnoid pressure was observed in all five patients placed in the Trendelenburg position. CONCLUSIONS: Subarachnoid pressure of the optic nerve can be measured in vivo in humans. The values obtained are consistent with the known physiologic range of intracranial pressure. There was no statistically significant correlation between subarachnoid pressure of the optic nerve and age or cause of blindness. The subarachnoid pressure of the optic nerve varies over a wide range.

Adolescent↗

Sensitive detection of occult Ewing's cells by the reverse transcriptase-polymerase chain reaction.

Recently, Ewing's tumours have been shown to carry specific hybrid transcripts resulting from the fusion of the EWS gene with FLI-1 or ERG genes. Based on the sensitivity and specificity of the detection of these alterations by the reverse transcriptase-polymerase chain reaction technique, we have developed an assay to search for small numbers of Ewing cells in various sites from patients with Ewing's tumour. This method enables the detection of fewer than one tumour cell per million blood mononuclear cells. A total of 28 primary sites and 51 peripheral samples from 36 patients were investigated. Tumour cells could be detected in 4/18 blood samples, 4/15 bone marrow aspirates and 2/18 peripheral stem cell harvests. EWS/FLI-1 and EWS/ERG transcripts being observed in eight and two cases respectively. The type of fusion transcript detected in peripheral site(s) was identical to that observed in the primary site. At diagnosis 5/16 patients (31%) demonstrated either circulating tumour cells or/and occult bone marrow metastasis. After induction therapy, tumour cells were detected in 3/21 patients. This highly sensitive method should be a relevant tool to allow a more accurate clinical assessment of the dissemination of Ewing's tumours.

Base Sequence↗

Evidence for two tumour suppressor loci on chromosomal bands 1p35-36 involved in neuroblastoma: one probably imprinted, another associated with N-myc amplification.

Previous reports on possible genomic imprinting of the neuroblastoma tumour suppressor gene on chromosome 1p36 have been conflicting. Here we report on the parental origin of 1p36 alleles lost in 47 neuroblastomas and on a detailed Southern blot analysis of the extent of the 1p deletions in 38 cases. The results are remarkably different for tumours with and without N-myc amplification. In the N-myc single copy tumours we show that the lost 1p36 alleles are of preferential maternal origin (16 of 17 cases) and that the commonly deleted region maps to 1p36.2-3. In contrast, all N-myc amplified neuroblastomas have larger 1p deletions, extending from the telomere to at least 1p35-36.1. These deletions are of random parental origin (18 of 30 maternal LOH). This strongly suggests that different suppressor genes on 1p are inactivated in these two types of neuroblastoma. Deletion of a more proximal suppressor gene is associated with N-myc amplification, while a distal, probably imprinted, suppressor can be deleted in N-myc single copy cases.

Chromosome Deletion↗

[Immunotherapy of malignant diseases].

Cancer immunotherapy has been carried out since the early fifties and first involved nonspecific system (BCG, Corynebacterium parvum, levamisole...). More recently, the production of cytokines as interferons or interleukin 2, the introduction of monoclonal antibodies have allowed a new development to cancer immunotherapy. Nevertheless, these new approaches have to be considered as a step in the biological therapy of cancer.

Animals↗