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Biomedical subjects

L Castagna

Publications and source records attributed to L Castagna.

25 records · Page 2Linked to original sources
PubMed1996

Regulated expression of a 16-kd galectin-like protein in activated rat macrophages.

We investigated the presence of a galectin-like protein in rat mononuclear cells using a polyclonal antibody raised against a soluble lactose-binding lectin purified from adult chicken liver that immunoreacted strongly with a broad protein band of about 16 kd in Western blot assays. Immunochemical studies revealed a constitutive expression of this protein in mononuclear cells mainly in the macrophage (M phi) population. Subcellular localization was assessed by Western blot assays of the cytosolic and membrane fractions of different cell populations studied: (1) spleen mononuclear cells, (2) T cell-enriched, (3) B cell- and M phi-enriched populations, and (4) peritoneal cells, processed in the presence of lactose. In broad agreement with immunocytochemical studies of nonpermeabilized and permeabilized cells, Western blot assays suggest that this protein is localized mainly in the cytoplasmic compartment but also associated with the cell surface. By flow cytometric analyses we detected about a 14% of ED1 double-positive cells corresponding to macrophages that constitutively express this galectin-like protein associated with their cell surface. The cytosolic fraction obtained from the M phi-enriched cell population showed hemagglutinating activity specifically inhibited by beta-galactoside-related sugars. Moreover, this galectin-like protein was retained in a lactosyl-Sepharose matrix and specifically eluted with lactose. In this work, evidence is also provided to show that different stimuli are able to modulate the expression of the galectin-like protein. Expression was upregulated in inflammatory and activated macrophages, revealing a significant increase in phorbol ester- and formylmethionine oligopeptide-treated cells. Both stimuli involving protein kinase C activation pathway have been able not only to up-regulate the total expression of this protein but also to modulate its subcellular localization.

Animals↗
PubMed1996

Isolation and partial characterization of N-acetyl-D-galactosamine-binding lectins from Epiphragmophora trenquelleonis snail.

A human blood type A hemagglutinating activity was detected in albumin gland extracts of Epiphragmophora trenquelleonis snail separated by GalNAc-agarose affinity chromatography, of which two N-acetyl-D-galactosamine-binding lectins in the extracts were ETL1 was displaced from the affinity column with 1 mM GalNAc, and ETL2 with 20 mM GalNAc. Both lectins agglutinated specifically human blood type A and AB erythrocytes, but not type B and O erythrocytes. Gel filtration chromatography gave a native molecular weight of about 59 kDa for ETL1 and about 54 kDa for ETL2. On SDS-PAGE under nonreducing conditions, ETL1 showed two protein subunits of about 29 and 27 kDa, while ETL2 showed three protein subunits of about 27, 24, and 22 kDa. On SDS-PAGE under reducing conditions, both lectins showed four protein subunits of 17, 16, 12, and 11 kDa. By Western blot analyses developed with biotin-labeled lectins, N-linked oligosaccharides were detected in the 17- and 16-kDa protein subunits of ETL1 and ETL2, and in the 12-kDa protein subunit of ETL2. O-linked oligosaccharides were detected only in the 11-kDa protein subunit of ETL1 and ETL2. On isoelectric focusing both lectins exhibited microheterogeneity: ETL1 focused as three protein bands with pIs in the range of 5.6-6.0, while ETL2 focused as four protein bands with pIs in the range of 6.8-7.4. We suggest that native ETL1 and ETL2 are glycoprotein complexes with molecular weights of 59-54 kDa, composed of two 29-22-kDa nonreduced protein subunits held together by noncovalent hydrophobic interactions. Each of the nonreduced protein subunits seems to be composed of two 17-11-kDa reduced protein subunits held together by interchain disulfide linkages. The main differences between ETL1 and ETL2 could be due to different posttranslational modifications or to the relative contribution of one or more of their protein subunits.

Acetylgalactosamine↗
PubMed1993

Escalating high-dose carboplatin and autologous bone marrow transplantation in solid tumors.

Twenty-seven patients with poor-prognosis malignancies were treated with a combination (CARBOPEC) of fixed-dose etoposide (1,750 mg/m2), cyclophosphamide (6,400 mg/m2), and escalating doses of carboplatin (from 800 to 1,600 mg/m2) followed by autologous bone marrow transplantation (ABMT). All patients had previously received platinum derivatives. The diagnoses were as follows: germ cell tumors (GCTs; n = 15); ovarian carcinomas (n = 8); rhabdomyosarcomas (n = 3), and Hodgkin's disease (n = 1). All 27 patients were fully evaluated for toxicity. The median duration of granulocytopenia (leukocytes < 0.5 x 10(9)/l) and thrombocytopenia (platelets < 20 x 10(9)/l) was 23 and 20 days, respectively. Hematologic growth factors were used in 3 cases. The main nonhematologic toxicity was gastrointestinal, with moderate to severe diarrhea in 18 patients. No significant renal toxicity was observed. The overall response rate to this high-dose chemotherapy was 55%, with a complete response (CR) rate of 45% (9 patients). The median duration of CR was 9 months. Five of the 27 patients are alive with no evidence of disease (NED) at 5, 22, 27, 40, and 43 months after ABMT. Four of the 11 patients with refractory GCTs have NED at 5, 22, 27, and 40 months, together with 1 of the 3 responders (43 months). Our study shows the encouraging antitumor activity of this regimen. Similar chemotherapy schedules have also been used with high response rates in GCT, ovarian cancer, breast cancer, and soft tissue sarcoma in children. The CARBOPEC protocol seems to be a good candidate for therapy intensification in patients with various malignancies. A European trial for salvage therapy in GCT will be activated in the near future. Moreover, results should improve with the widespread use of hematopoietic growth factors and optimization of carboplatin administration that takes pharmacokinetic parameters into account.

Adolescent↗