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Biomedical subjects

M Schell

Publications and source records attributed to M Schell.

At least 19 recordsLinked to original sources
PubMed2006

[Childhood cancer incidence and survival rates in the Rhône-Alpes regional paediatric registry 1987-1999].

UNLABELLED: Cancer is rare in children, and pediatric malignancies represent only 1% of all cancers. OBJECTIVES: The cure rate is high and increasing, and ongoing data collection is therefore warranted. MATERIALS AND METHODS: Here we report the incidence and survival rates of childhood cancers between 1987 and 1999 in the Rhône-Alpes region of France. RESULTS: A total of 1945 cases were recorded during the study period, with an average of 149.6 new cases per year. The approximate incidence rate was 134.1/10(6) per year and the age-standardized incidence rate was 139.2/10(6) per year. The histological distribution and 5-year survival rates were respectively 30.2 and 73% for leukemia, 12.3 and 91.6% for lymphoma, 24.7 and 60.1% for CNS tumors, 9.1 and 71.1% for neuroblastoma, 2.5 and 94.1% for retinoblastoma, 5.8% and 89.9% for renal tumors, 1 and 75% for liver tumors, 6.1 and 60.9% for bone tumors, 4.1 and 58.6% for soft-tissue tumors, 1.1 and 71% for germ cell tumors, and 2.4 and 85.1% for carcinomas. CONCLUSION: The overall survival rate was 75%. Long-term treatment complications warrant further studies of children who survive into adulthood.

Adolescent↗
PubMed2004

Primary cardiac Burkitt lymphoma in a child.

Primary cardiac lymphoma (PCL) is a rare and usually fatal malignancy, seldom reported in children. This report describes the case of a 10-year-old boy who presented with multiple intracardiac masses which, when biopsied, proved to be small non-cleaved cell (Burkitt's) lymphoma. The first two cycles of chemotherapy according to the LMB 96 protocol were given under close cardiological supervision, with good response. The treatment was then continued with full-dose chemotherapy, without any cardiological complication. The patient who was treated by chemotherapy alone remains in complete remission 36 months after the end of treatment and can presently be considered as cured, without late cardiac effect.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2004

[Case report: lymphosarcoma in a cow].

A case of sporadic lymphosarcoma in a cow is described. The animal showed a tumorous mass in the area of the right orbita accompanied by conjunctival oedema. Clinical investigation showed an enlargement of a number of internal and external lymph nodes. Haematological and clinicochemical investigations revealed no alterations besides a slight shift to the right in the white blood picture. Blood serum was negative for antibodies directed against bovine leucosis virus. Necropsy showed leucotic and tumorous alterations in a number of organs.

Animals↗
PubMed2001

External beam irradiation for inhibition of intimal hyperplasia following prosthetic bypass: preliminary results.

To determine whether external beam irradiation delivered immediately after graft implantation can inhibit anastomotic intimal hyperplasia (IH) 1 month following polytetrafluoroethylene (PTFE) bypass in a sheep carotid artery model, 23 sheep underwent bilateral bypass of the ligated common carotid artery with 8-mm PTFE immediately followed by a single dose of irradiation (15, 21, or 30 Gy) to one side. The 15 animals with bilaterally patent grafts were euthanized at 1 month and graft-arterial anastomoses harvested. Using computer-aided image analysis, IH areas and thicknesses were measured. Graft patency in this model was 83% at 1 month and did not differ according to treatment administered. In the control animals, IH was greatest at mid-anastomosis, but minimal within the native vessel. All three radiation doses markedly inhibited mid-anastomotic IH area and thickness. At the proximal anastomosis, 30 Gy reduced the IH area 20-fold, from 2.06 to 0.14 mm2 (p < 0.0001 by ANOVA), and IH thickness 70-fold, from 29.0 to 0.4 micron (p < 0.0002); similar effects were seen at the distal anastomosis. No adverse effects of radiation treatment were observed. External beam irradiation in doses of 15 to 30 Gy delivered in a single fraction immediately after operation markedly inhibits development of intimal hyperplasia 1 month following end-to-side anastomosis with PTFE in sheep.

Animals↗
PubMed2001

[Immunization for children treated for solid tumors: what are the guidelines?].

There is no agreement on immunization of children treated with chemotherapy (CT) for solid tumors. Based on a review of the literature, we have attempted to establish guidelines on this subject. Except for hepatitis B vaccine, there is no argument to support the use of vaccine during CT. After a standard CT, a 3-month washout period appears to be necessary before starting an immunization program for a child not previously vaccinated, or to proceed with the recommended booster injections for diphteria anatoxin, tetanus vaccine, poliomyelitis inactivated vaccine, pertussis vaccine, and haemophilus influenza type b vaccine if the child is less than 5 years old. For mumps, measles, and rubella live vaccines, a longer post-CT washout of 6 months is suggested for the initial immunization, or for a revaccination of a child proved to be negative for all three serologies. Following high-dose CT a minimal 12-months term and a normalization of the blood lymphocytes count is necessary before planning booster injections once having checked for antidiphteria, tetanic, polio, measles, mumps, rubella and +/- haemophilus antibody titles. We don't find any reason to recommend a systematic varicella immunization in pediatric oncology. Pneumococcal vaccine is recommended in case of asplenia. Any other vaccination (BCG, influenza, yellow fever) must be evaluated individually.

Age Factors↗
PubMed2001

Fading renal hyperfiltration in children following liver transplantation.

In a prospective longitudinal study, we investigated the renal function (RF) of 23 children before and after orthotopic liver transplantation (OLT). The aim was to assess both the outcome of pretransplant hyperfiltration and the clinical nephrotoxic effects of cyclosporin A (CsA); children with decreased RF prior to OLT were therefore excluded. The RF study of the 13 remaining patients included glomerular filtration rate (GFR) and effective renal plasma flow (RPF) measured by inulin (Cin: mL/min/1.73 m2) and para-amino hippurate (Cpah: mL/min/1.73 m2) clearances, respectively. Hyperfiltration prior to OLT was observed in six children, i.e. Cin>170 [range 172-230] and Cpah>800 [808-1,133]. A significant decrease in RF was noted as soon as 6 months after OLT: Cin (mean+/-SD)=107+/-23 vs. 158+/-46 (p<0.003); Cpah=583+/-119 vs. 791+/-243 (p<0.004). This was due to loss of hyperfiltration in the six children, as there was no significant difference in RF before and 6 months after OLT in the other seven children. With a 36-month follow-up, there was no correlation between CsA trough blood level and RF. In conclusion, following OLT, RF underwent early changes owing to loss of prior hyperfiltration in children without impaired RF before OLT. In addition, no evidence of CsA nephrotoxicity was found and RF remained stable during follow-up.

Acute Kidney Injury↗
PubMed2001

[School reinsertion of children treated for tumors of the brain: experience of the Léon-Bérard center].

School integration of children with brain tumor is part of the quality of their life. It may also become a nightmare both for the child and for the teacher when no recommendation has been addressed to the latter. In France, official recommendations allow the meeting and information exchanges in the school between teachers and all the people who take care medically of the child. We report our experience in Centre Léon-Bérard of Lyon, concerning 38 children with brain tumors (102 meetings). Though difficult to assess scientifically, the benefit from these meetings is obvious. For the teachers: the knowledge and understanding of the physiopathology of brain tumors and secondary sequellae facilitates teaching. For the child: the disappearance of surrounding fears and fantasms make life easier. This experience is so rich that it should be extended to other pathologies.

Adolescent↗
PubMed2000

Antibody-mediated resolution of light chain-associated amyloid deposits.

Primary light-chain-associated (AL) amyloidosis is characterized by the deposition in tissue of monoclonal light chains as fibrils. With rare exception, this process is seemingly irreversible and results in progressive organ dysfunction and eventually death. To determine whether immune factors can effect amyloid removal, we developed an experimental model in which mice were injected with amyloid proteins extracted from the spleens or livers of patients with AL amyloidosis. Notably, the resultant amyloidomas were rapidly resolved, as compared to controls, when animals received injections of an anti-light-chain monoclonal antibody having specificity for an amyloid-related epitope. The reactivity of this monoclonal antibody was not dependent on the V(L) or C(L) isotype of the fibril, but rather seemed to be directed toward a beta-pleated sheet conformational epitope expressed by AL and other amyloid proteins. The amyloidolytic response was associated with a pronounced infiltration of the amyloidoma with neutrophils and putatively involved opsonization of fibrils by the antibody, leading to cellular activation and release of proteolytic factors. The demonstration that AL amyloid resolution can be induced by passive administration of an amyloid-reactive antibody has potential clinical benefit in the treatment of patients with primary amyloidosis and other acquired or inherited amyloid-associated disorders.

Amyloid↗
PubMed2000

Irradiation for intimal hyperplasia: implications for peripheral arterial bypass.

Irradiation has been shown to inhibit postangioplasty intimal hyperplasia ("restenosis") in unbranched tubes. It seems likely that irradiation will similarly be able to inhibit intimal hyperplasia after a surgical anastomosis at a biochemical and cellular level, but whether it will produce a clinically relevant or even clinically detectable difference is unproved. One possibility is that no clinical effect may occur; the search for a "cure" for intimal hyperplasia has been long and, as yet, unsuccessful. On the other hand, if a strong effect without insurmountable logistical problems could be produced, one major cause of bypass graft failure would be preventable. Not only would the incidence of late graft occlusion, need for reoperation, and limb loss be reduced, but, if patency of prosthetics could be sufficiently improved, the initial operation could be made much easier, faster, and perhaps safer.

Angioplasty, Balloon↗
PubMed2000

Has the mammography quality standards act affected the mammography quality in North Carolina?

OBJECTIVE: The United States Food and Drug Administration implemented federal regulations governing mammography under the Mammography Quality Standards Act (MQSA) of 1992. During 1995, its first year in implementation, we examined the impact of the MQSA on the quality of mammography in North Carolina. MATERIALS AND METHODS: All mammography facilities were inspected during 1993-1994, and again in 1995. Both inspections evaluated mean glandular radiation dose, phantom image evaluation, darkroom fog, and developer temperature. Two mammography health specialists employed by the North Carolina Division of Radiation Protection performed all inspections and collected and codified data. RESULTS: The percentage of facilities that met quality standards increased from the first inspection to the second inspection. Phantom scores passing rate was 31.6% versus 78.2%; darkroom fog passing rate was 74.3% versus 88.5%; and temperature difference passing rate was 62.4% versus 86.9%. CONCLUSION: In 1995, the first year that the MQSA was in effect, there was a significant improvement in the quality of mammography in North Carolina. This improvement probably resulted from facilities' compliance with federal regulations.

Mammography↗
PubMed1999

Thermodynamic instability of human lambda 6 light chains: correlation with fibrillogenicity.

Certain types of human light chains have the propensity to deposit pathologically as amyloid fibrils as evidenced by the preferential association of monoclonal lambda 6 proteins with AL amyloidosis. However, the molecular features that render such proteins amyloidogenic have not been elucidated. Based upon the demonstrated relationship between the thermodynamic stability of light chains and their propensity to aggregate in vitro, we have initiated studies where the thermodynamic properties and fibrillogenic potential of two recombinant (r) V lambda 6 molecules were compared. The first protein was generated from cDNA cloned from marrow-derived plasma cells from a patient (Wil) who had AL amyloidosis and renal amyloid deposits; the second was from a patient (Jto) with multiple myeloma in whom the lambda 6 protein was deposited not as amyloid but in the form of renal tubular casts. The thermodynamic stabilities of rV lambda 6Wil and -Jto were determined from chaotropic and thermal denaturation studies. Based upon the Delta GH2O, Delta H, Delta G25 degrees C, Tm, and Cm values, the rV lambda 6Wil was less stable than its nonamyloidogenic counterpart, rV lambda 6Jto. Measurement of fibril formation using a novel in vitro fibril forming assay demonstrated that although both rV lambda 6 proteins formed fibrils in vitro, Wil had a shorter lag time and exhibited faster kinetics under physiologic conditions. Comparative amino acid sequence analyses of these two components and other lambda 6 amyloid-associated light chains revealed that the Jto protein had certain primary structural features that we posit contributed to its increased stability and thus rendered this protein nonamyloidogenic. Our studies provide the first evidence that stabilizing interactions within the V L domain can influence the kinetics of light chain fibrillogenicity.

Amino Acid Sequence↗
PubMed1999

Five year results of LINAC radiosurgery for arteriovenous malformations: outcome for large AVMS.

PURPOSE: For radiosurgery of large arteriovenous malformations (AVMs), the optimal relationship of dose and volume to obliteration, complications, and hemorrhage is not well defined. Multivariate analysis was performed to assess the relationship of multiple AVM and treatment factors to the outcome of AVMs significantly larger than previously reported in the literature. METHODS AND MATERIALS: 73 patients with intracranial AVMs underwent LINAC radiosurgery. Over 50% of the AVMs were larger than 3 cm in diameter and the median and mean treatment volumes were 8.4 cc and 15.3 cc, respectively (range 0.4-143.4 cc). Minimum AVM treatment doses varied between 1000-2200 cGy (median: 1600 cGy). RESULTS: The obliteration rates for treatment volumes < 4 cc, 4-13.9 cc, and > or = 14 cc were 67%, 58%, and 23%, respectively. AVM obliteration was significantly associated with higher minimum treatment dose and negatively associated with a history of prior embolization with particulate materials. No AVM receiving < 1400 cGy was obliterated. The incidence of post-radiosurgical imaging abnormalities and clinical complications rose with increasing treatment volume. For treatment volumes > 14 cc receiving > or = 1600 cGy, the incidence of post-radiosurgical MRI T2 abnormalities was 72% and the incidence of radiation necrosis requiring resection was 22%. The rate of post-radiosurgical hemorrhage was 2.7% per person-year for AVMs with treatment volumes < 14 cc and 7.5% per person-year for AVMs > or = 14 cc. CONCLUSION: As AVM size increases, the dose-volume range for the optimal balance between successful obliteration and the risk of complications and post-radiosurgical hemorrhage narrows.

Adolescent↗
PubMed1999

Transgenic mouse model of AA amyloidosis.

AA amyloidosis can be induced in mice experimentally through injection of certain chemical or biological compounds. However, the usefulness of this approach is limited by its dependence on exogenous inflammatory agents that stimulate cytokines to increase the synthesis of precursor serum amyloid A (SAA) protein and the transitory nature of the pathological fibrillar deposits. We now report that transgenic mice carrying the human interleukin 6 gene under the control of the metallothionein-I promoter had markedly increased concentrations of SAA and developed amyloid in the spleen, liver, and kidneys by 3 months of age. At the time of death about 6 months later, organs obtained from these animals had extensive amyloid deposits. This disease process was apparent radiographically using small-animal computer axial tomography and magnetic resonance imaging equipment. The AA nature of the amyloid was evidenced immunohistochemically and was unequivocally established by sequence analysis of protein extracted from the fibrils. The availability of this unique in vivo experimental model of AA amyloidosis provides the means to assess the therapeutic efficacy of agents designed to reduce or prevent the fibrillar deposits found in AA and other types of amyloid-associated disease.

Amino Acid Sequence↗
PubMed1999

Intravascular brachytherapy physics: report of the AAPM Radiation Therapy Committee Task Group no. 60. American Association of Physicists in Medicine.

Recent preclinical and clinical studies indicate that irradiation using ionizing radiation in the dose range of 15 to 30 Gy may reduce the occurrence of restenosis in patients who have undergone an angioplasty. Several delivery systems of intravascular brachytherapy have been developed to deliver radiation doses in this range with minimal normal tissue toxicity. In late 1995 the American Association of Physicists in Medicine (AAPM) formed a task group to investigate these issues and to report the current state of the art of intravascular brachytherapy physics. The report of this task group is presented here.

Angioplasty, Balloon, Coronary↗