Biomedical subjects

C Pondarre

Publications and source records attributed to C Pondarre.

4 recordsLinked to original sources

PubMed2000

[Hematopoietic stem cells].

Hematopoietic stem cells, which share with other stem cells of adult tissues the ability to maintain constant the number and diversity of differentiated mature cells throughout adult life offer a fabulous system to analyze mechanisms controlling cell proliferation and differentiation. Cytokines controlling the differentiation of intermediate progenitors into mature cells of the various lineages have been characterized and have been widely used, in vitro as in vivo, to increase the output of differentiated cells. In contrast, despite significant technological advances, molecular events associated with the stem cell decisions first to either self-renew or differentiate, and then to irreversibly commit to one of the lymphoid or of the myeloid pathways are still very badly understood. This is partly explained by the lack of reliable assays, particularly in humans, to assess stem cell activity, and by the difficulty to dissect the composition of molecular complexes regulating gene expression in these very rare cells. Despite these limitations, recent evidence suggests that there is some flexibility in the initial decisions of stem cells, and that extracellular factors may influence stem cell fate. If this is confirmed, it may then become possible to propose new therapeutic strategies based on the manipulation of stem cell properties.

Hematopoietic Stem Cells↗

PubMed1995

[Tetraparesis in an infant after prolonged administration of pancuronium].

Long-term administration of pancuronium for ventilatory support of adults with ARDS may result in severe tetraparesis, with areflexia and atrophy of distal muscles. This adverse effect occurs rarely in paediatric intensive care units. We describe a case of tetraparesis after prolonged pancuronium infusion in a 9-month-old girl who experienced a severe bronchopneumonia caused by para-influenza virus, requiring endotracheal intubation and mechanical ventilation. To decrease chest wall rigidity, pancuronium was administered over 11 days, with a total dose of approximately 120 mg of pancuronium bromide. The day after discontinuation of the muscle relaxant she had a severe tetraplegia with areflexia, but normal head movements. Electromyography showed a normal neuromuscular transmission. She recovered from tetraplegia three months later. Other causes of peripheral neuropathy were eliminated. Electroencephalograms and head CT-scans were normal. The recovery pattern observed in our patient corresponded to the process of regeneration seen after axonal degeneration. It is suggested that these neuromuscular complications were caused by prolonged high-dosage pancuronium treatment, associated with corticosteroid and aminoglycoside administration.

Bronchopneumonia↗

PubMed1994

Desmoplastic small round cell tumors of the abdomen.

BACKGROUND: Desmoplastic small round cell tumors (DSRCT) have been only recently identified. METHODS: The authors report DSRCT in two pediatric patients (an 8-year-old boy and 12-year-old boy). In both patients, the initial diagnosis was rhabdomyosarcoma. The resistance to standard chemotherapy and radiation therapy prompted the authors to review the initial biopsy specimens and perform complementary immunophenotypic characterization. RESULTS: These analyses revealed that the tumor cells were strongly positive for keratin epithelial marker antigen, desmin, vimentin, neurospecific enolase, and S100 protein, corresponding to pleomorphic differentiation, characteristic of DSRCT: CONCLUSIONS: The authors suggest that extensive immunohistologic characterization be performed in all cases of small round cell tumors of the abdomen so that the diagnosis of DSRCT is not overlooked. These rare tumors are refractory to chemotherapy, and initial aggressive surgery is warranted.

Antigens, Neoplasm↗

PubMed1993

Successful treatment for a metastatic supratentorial malignant rhabdoid tumor.

The case of a boy with a familial history of Rendu-Osler disease, who successively developed a cerebellar pilocytic astrocytoma (at 3 years of age) and a metastatic supratentorial malignant rhabdoid tumor (at the age of 12 years) is reported. After a complete surgical removal, the CSF was cleared by 4 courses of chemotherapy, and the child received a craniospinal irradiation. He is currently alive and well 19 months after completion of the treatment. The authors discuss the ethiopathogeny of such intracranial tumors and argue for aggressive treatment.

Astrocytoma↗