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Biomedical subjects

F Freycon

Publications and source records attributed to F Freycon.

At least 37 records · Page 2Linked to original sources
PubMed1992

In utero transplantation of stem cells in humans: immunological aspects and clinical follow-up of patients.

Four human fetuses were treated by transplantation of human fetal liver stem cells. Two of them had severe immunodeficiency disease and the two other ones had thalassemia major. Three of these in utero transplants were followed by engraftment. The three patients are now born: the first one is now very healthy thanks to the reconstitution of cell-mediated immunity associated with this transplant, and he lives normally at home; the two other ones, who have been more recently treated, have a significant improvement of their condition and they also live normally at home. This procedure, for the first time used in humans, has therefore demonstrated its feasibility and its efficacy: during early fetal development, foreign cells engraft readily and may result in cure or significant correction of a large variety of inherited diseases.

Blood Transfusion, Intrauterine↗
PubMed1992

[Study of serum kinetics of vancomycin during the "antibiotic-lock" technique].

The serum kinetics of vancomycin was studied in two patients aged 3 and 15 years during antibiotic therapy for catheter related sepsis associated with Staphylococcus epidermidis. Vancomycin was administered, simultaneously, by parenteral conventional doses (30 mg/kg/day div q 8 h) and using the antibiotic-lock technique in the infected catheter at a high concentration (150 mg/ml) during one hour, 3 hours after each infusion. Pharmacokinetics data did not show any significant change in the serum kinetics of the antibiotic. The results suggest that delivering a high concentration of vancomycin in the infected catheter using the lock technique may be useful to sterilize infected catheter without toxic effect.

Adolescent↗
PubMed1991

Genotype-phenotype relationship in various degrees of arylsulfatase A deficiency.

Arylsulfatase A (ASA) is a lysosomal enzyme that hydrolyzes sulfatide. Absence of ASA activity leads to metachromatic leukodystrophy (MLD). The clinical outcome resulting from ASA deficiency is highly variable with respect to age of onset and symptoms. So far the causes for the variability are poorly understood. We have studied the relationship between the ASA genotype and the clinical phenotype. Fibroblasts from a total of 34 subjects with low ASA activity were examined with immunoblotting, a sensitive ASA assay, and the sulfatide loading test in order to characterize low ASA activity further. By these methods, three different classes of ASA deficiency can be defined: homozygosity for the pseudodeficiency allele (ASAp), compound heterozygosity for the ASAp and MLD (ASA-) alleles, and ASA-/ASA- genotypes. These genotypes exhibit different levels of ASA residual activity. Only ASA-/ASA- genotypes are associated with MLD. For diagnostic purposes, however, the differentiation of the various ASA genotypes is essential.

Adolescent↗
PubMed1991

[Alexander's disease].

Alexander disease, or hypoproconvertinemia is a rare autosomic recessive coagulation disorder. The features include familial and/or personal history of bleeding, with an abnormal prothrombin period and a normal activated partial thromboplastin period. Coagulation and genetic studies allow subclassification with prognosis incidence for this disease. The authors report on a case of one family with Alexander disease.

Child↗
PubMed1991

[Growth factors and oncogenes in brain tumors: the model of glioblastoma and medulloblastoma].

Glioblastomas and medulloblastomas are models for studying the implication of growth factors and oncogenes in tumor development. Amplification and/or hyperexpression of oncogenes result in products that may mimic growth factors and/or their receptors; cells may demonstrate autocrine and/or paracrine activity. Prognostic implications of such findings are suggested.

Brain Neoplasms↗
PubMed1991

[Chromosome anomalies in brain tumors].

The authors review the literature concerning chromosomal abnormalities in childhood brain tumors: medulloblastomas, ependymomas, and gliomas of low and high grade. Though these technics require further development, they highlight the role of cytogenetic modification in oncogenesis of brain tumors.

Astrocytoma↗
PubMed1991

[Medulloblastoma].

Medulloblastoma is a frequent brain tumor in childhood. Recent advances in histogenesis, management of early and late side-effects, and prognosis are discussed in this review.

Cerebellar Neoplasms↗
PubMed1991

New developments in stem cell transplantation with special reference to the first in utero transplants in humans.

Based on the experience acquired in post-natal liver transplantation since 1974, we recently initiated pre-natal, in utero stem cell transplantation from the human fetal liver. The first two fetuses that we treated had immunodeficiencies, the third one had thalassemia major. Donors and recipients were not matched. The fetal cells were infused in the umbilical vein of the first two patients and injected intraperitoneally into the third one, under ultrasonic visualization. The first patient, born in 1988, has both engraftment of donor cells and reconstitution of cell-mediated immunity. This child, who had bare lymphocyte syndrome, has no clinical manifestation of the disease and he lives normally at home. The second child, born in 1989, has not yet developed a significant reconstitution of immunity although donor cell engraftment has been proven (Y chromosome in this female patient). The third patient has also evidence of donor cell take (Y chromosome in a female patient) but the effect on thalassemia has not yet been fully analyzed (donor hemoglobin present in small quantity). In all 3 cases, no side-effect of any kind developed in the mother nor in the fetus. Several advantages appear to be associated with in utero FLT: increased probability of graft take, ideal isolation of patient (in the uterus), optimal environment for fetal cell development (in the fetal host).

Female↗
PubMed1990

[Allogenic bone marrow graft in thalassemia major. The French experience].

From August 1985 to April 1988, 17 patients have been allografted in France for TM. Fourteen (82%) are alive, 10 (58%) are cured and 4 in autologous reconstitution. Three died, 2 of whom after a second transplantation, and 2 due to CMV interstitial pneumonia. Ten of 17 were conditioned by cyclophosphamide (Cy: 200 mg/kg) and busulfan (Bu: 14 mg/kg): 10 are alive, 6 cured and 4 in autologous reconstitution. Five received Cy (200 mg/kg) Bu (16 mg/kg) +/- total lymphoid irradiation (TLI) (3 patients): 2 patients are cured (one after hepatic veno-occlusive disease), and 3 died. For 2 patients, conditioning included total body irradiation: both are cured. Graft versus host (GVH) reaction prevention included: 4 T cell depletion (with additional prevention in 3; 2 are cured, one is in autologous reconstitution, 1 died); 5 cyclosporine alone (2 cured, 2 autologous reconstitution, 1 dead) and 8 cyclosporine + methotrexate (6 cured, 1 autologous reconstitution, 1 dead). Four of 12 evaluable patients presented a less than or equal to 2 grade acute GVHd. None had received a T cell depleted marrow. Bone marrow transplantation is the only curative treatment currently available for TM patients with HLA identical donors. It should be proposed to any young patient before iron overload is established. Optimal conditioning includes Cy (200 mg/kg) + Bu (14 mg/kg). The best protocol for GVHd prevention remains to be defined.

Adolescent↗
PubMed1989

[Serum concentrations of 25 hydroxyvitamin D in hospitalized infants. Relation to calciuria].

In attempt to evaluate the vitamin D status of the infants of our area under the mode of prophylaxis of carential rickets actually used in France, serum 25 hydroxyvitamin D (25 OHD) levels were measured in 65 infants (age 3 - 32 months) during their hospitalisation for acute illness. Most infants were receiving vitamin D either in daily doses (1,200 - 1,600 u) or in unique loading doses (200,000 - 600,000 u every 4 - 6 months). With this prophylaxis serum concentrations of 25 OHD were elevated, i.e. above 75 nmol/l, in more than 50% of the infants, reaching 474 nmol/l in one case. Calciuria estimated by the calcium/creatinine urinary ratio tended to increase in parallel with the serum 25 OHD level. From these data it is concluded that the actual prophylaxis of carential rickets in France frequently uses excessive doses of vitamin D and that new rules have to be established.

Calcifediol↗
PubMed1988

[Familial nephrogenic diabetes insipidus with chronic hypernatremia and cerebral calcifications].

The authors report on the unusual evolution of two brothers suffering from nephrogenic diabetes insipidus after a 25-year follow-up. The polyuro-polydipsic syndrome was clinically well tolerated, without acute complications even during infancy. However, despite the lack of water restriction and the presence of thirst sensation, the children remained chronically hypernatremic. An intellectual deficiency was present, with a dysmorphic syndrome unrelated to a biochemically determined central nervous system disorder, or an X fragility. Calcifications of basal ganglia and frontal lobes were discovered on a cerebral computed tomography performed at 16 and 18 years. This syndrome may represent a specific entity.

Adult↗
PubMed1988

[The contribution of cytogenetics to the evaluation of residual disease in malignant hemopathies].

Autologous bone marrow transplantation is now a major tool in the treatment of human leukemias and lymphomas. Evaluation of residual disease by standard cytological methods is difficult. Cytogenetics provide clonal markers which are specific features of leukemic cells. Detection of minimal disease by chromosomal methods is possible in acute leukemias, it requires karyotyping of a few hundred metaphases from a short term culture. A preselection of the material to be examined will improve the degree of sensitivity of the method.

Bone Marrow↗
PubMed1988

Collagen biosynthesis in a case of infantile myofibromatosis.

Cells from a skin nodule from a patient with a recurrent form of familial myofibromatosis were cultivated in vitro. A metabolic study showed that these cells behaved like fibroblasts with collagen synthesis, a normal percentage of type III collagen, hydroxylation rate and the ability to contract a collagen gel. The main disturbances were the decreased synthesis and increased cell multiplication rate after a lag phase. This behavior was compared with that of a fibroblast culture from normal skin.

Collagen↗