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Biomedical subjects

P Leoni

Publications and source records attributed to P Leoni.

At least 109 records · Page 6Linked to original sources
PubMed1983

Bone marrow cryopreservation: biological aspects.

Ten bone marrow suspensions have been cryopreserved by a Programmed Freezer Planer R 201. Total cellularity, viability, differential myelograms, cytochemical pattern and CFU-GM growth "in vitro", have been evaluated on the cellular suspensions both before and after 1 and 18 months of storage in liquid nitrogen. Total cellular recovery and viable cell recovery were satisfactory, cellular loss being due, almost entirely to death of the more mature cells. NASDA reaction did not vary after freezing, on the contrary peroxidase reaction and overall PAS reaction showed respectively a slight and an almost complete disappearance. LAP reaction was not valuable, after freezing, because of the more mature myeloid cell loss. CFU-GM recovery was satisfactory and clusters and colonies growth in methylcellulose appeared quite similar before and after 1 and 18 months of storage at very low temperature. Our cryopreservation technique cannot prevent some cellular loss or some qualitative cellular damage, but colonizing ability is almost completely preserved.

Bone Marrow Cells↗
PubMed1983

Mechanisms of lysosomal enzyme secretion by human monocytes.

Secretion of lysosomal enzymes by human monocytes in response to various stimuli and the effect of conditioned media from lymphocytes and neutrophils was studied. Monocytes were found to release beta-glucosaminidase in response to NH4Cl and to particles (zymosan, opsonised zymosan, asbestos and latex), but do not respond to some soluble stimuli like formyl-methionyl-leucyl-phenylalanine, phorbol myristate acetate, cytochalasin B, concanavalin A and N-acetylmuramyl-L-alanyl-D-isoglutamine. Neutrophil conditioned medium or neutrophil components did not have any effect on secretion. When treated with lymphokines the cells are more responsive, especially to zymosan. Even through there are similarities in the secretory activities of mouse macrophages and human monocytes, there are several differences both in the quantity of the response and in the mechanisms involved.

Acetylglucosaminidase↗
PubMed1983

Mechanisms of lysosomal enzyme secretion by human U-937 monocytes.

Lysosomal enzyme secretion was studied in U-937, a mononuclear phagocyte cell line. The secretion of the marker enzyme, beta-N-acetyl-D-glucosaminidase, was low when the cells were challenged with phagocytosable stimuli (asbestos, zymosan, opsonised zymosan). Ammonium chloride and cytochalasin B induced secretion over 24 h of incubation. Phorbol myristate acetate and F-methyl-leucyl-phenylalanine, did not have any effect on secretion. It is suggested that U-937 cells may provide a useful model for the study of mononuclear phagocyte secretory pathways.

Acetylglucosaminidase↗
PubMed1982

The effect of weak bases on lysosomal enzyme secretion by mononuclear phagocytes.

NH4Cl induces a dose-dependent secretion of lysosomal enzymes by mouse peritoneal macrophages and human peripheral blood monocytes. The mechanism of NH4Cl-stimulated hexosaminidase release is distinct from that initiated by the inflammatory stimulus, zymosan. The spontaneous lysosomal secretion of the continuous murine macrophage-like cell line, P388D1, is inhibited by up to 50% in the presence of NH4Cl and other weak bases.

Ammonium Chloride↗
PubMed1977

[Lymphocyte typing in chronic lymphoid leukemia].

We used the membrane fluorescence and the rosette formation test to study the lymphocyte populations in 25 patients with untreated chronic lymphocytic leukemia (CLL). The results show a significant increase, absolute and percent of S-Ig bearing cells, whereas the E and EA rosette forming cells are decreased in per cent, increased in absolute. The number of lymphocytes with the receptor for the Fc fragment of IgG, is unchanged. The lymphocytosis causes mainly a significant decrease in percentage of E rosette forming cells. A big splenomegaly and a bad clinical stage, according to Rai et al. classification, are responsible for a decrease of E, EA, EAC rosette forming cells; unchanged the percentage of S-Ig bearing cells. Such a modification of the surface receptor pattern is present not only in those CLL more advanced in clinical stage and with hyperleucocitosis and/or splenomegaly, but also in those forms with worse clinical feature and prognosis. Our work confirms that CLL is mainly a B proliferative disease; we observed only one case due to T cell proliferation. Four cases were impossible to classify immunologically: one had no cells bearing the markers, three had a subnormal surface receptor pattern.

Adult↗
PubMedDate not supplied

Effectiveness of fludarabine in advanced B-cell chronic lymphocytic leukemia.

AIMS: The study was carried out to investigate the efficacy and toxicity of fludarabine phosphate in the treatment of B-cell chronic lymphocytic leukemia (B-CLL) in previously treated patients. METHODS: Sixteen patients, 11 males and 5 females, 9 in stage B and 7 in stage C, according to the Binet Staging System, were treated with a maximum of 6 cycles of fludarabine (25 mg/m2) for 5 days, every 4 weeks. All patients had been pretreated, 10 were refractory to standard regimens, 5 were in relapse, and 1 patient was in partial remission. RESULTS: Thirteen patients were judged suitable for evaluation. Overall 9 patients were responsive to treatment; 4 complete and 5 partial responses were observed. Of the 4 patients in complete remission, 3 were alive at 6, 10 and 13 months, respectively, from the beginning of treatment. One patient died after 11 months for acute graft-versus-host disease after allogenic bone marrow transplantation by an HLA sibling donor. Two of the 5 patients in partial remission were alive at 7 and 17 months, respectively, and the other 3 died (2 of disease reexpansion after 14 and 16 months and 1 of septic shock following pneumonia). Four patients were not responsive to treatment: 1 died from disease progression after 8 months from the beginning of therapy, 1 from cardiac failure after 9 months, 1 from septic shock following meningitis, and 1 was alive after 7 months of follow-up. Treatment was well tolerated, with nausea and vomiting in only one patient. We observed two episodes of pneumonitis, without any evidence of the responsible agent, a tumor lysis syndrome with acute renal failure, a recurrence of autoimmune thrombocytopenia, and a Coombs-positive hemolytic anemia. CONCLUSIONS: Fludarabine phosphate is effective in the treatment of patients with advanced B-CLL, even in those refractory to multiple chemotherapy regimens.

Aged↗