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Biomedical subjects

R Perez-Soler

Publications and source records attributed to R Perez-Soler.

103 records · Page 6Linked to original sources
PubMed1984

Clinical features and results of management of superior vena cava syndrome secondary to lymphoma.

Thirty-six of 915 patients with non-Hodgkin's lymphoma presented with superior vena cava syndrome (SVCS). The histologic types associated with SVCS were diffuse large cell in 23 patients, lymphoblastic in 12, and follicular large cell in one patient. Radiotherapy alone appeared equal to chemotherapy alone or in combination with radiotherapy in achieving relief of SVCS symptoms. Chemotherapy alone or in combination with radiotherapy was superior to radiotherapy alone in prolonging relapse-free survival and overall survival. No differences in relapse-free survival and survival were found between the patients treated with chemotherapy alone and those treated with chemotherapy and radiotherapy, but the addition of radiotherapy appeared to prevent local relapses in the group with large-cell lymphoma. The presence of symptoms of involvement of other mediastinal structures such as dysphagia, hoarseness, or stridor (DHS), a higher grade of intensity, and a shorter duration of symptoms (less than or equal to 2 weeks) appeared to adversely influence relapse-free survival and survival. The following conclusions were made: (1) a histologic diagnosis before the onset of treatment is desirable and feasible in patients presenting with SVCS except in those with severe respiratory distress, (2) both chemotherapy and radiotherapy are equally effective in alleviating the symptoms of SVCS, and (3) combined modality treatment with chemotherapy and radiotherapy results in a lower frequency of local relapses compared to chemotherapy alone but survival was similar in both groups.

Combined Modality Therapy↗
PubMed1984

Benign fibrous histiocytoma in Hodgkin's disease.

A case of benign fibrous histiocytoma in a patient with previous Hodgkin's disease is reported. Benign fibrous histiocytoma consists of a proliferation of benign histiocytes in addition to inflammatory cells and occasional Reed-Sternberg-like cells. Hodgkin's disease is considered a malignant disorder of the monocyte-histiocyte cell line but also includes benign inflammatory cells as part of its histological picture. The possibility that these two entities are biologically related is considered. The pathogenic relationship between both entities is discussed in the context of the immune dysregulation associated with Hodgkin's disease.

Histiocytoma, Benign Fibrous↗
PubMedDate not supplied

Phase I study of paclitaxel administered by ten-day continuous infusion.

PURPOSE: Pre-clinical data have suggested that prolonged exposure to paclitaxel enhances its cytotoxicity, but various clinical trials utilizing long-term infusions of paclitaxel have been limited by unacceptable hematologic toxicity, most notably significant neutropenia. A phase I study of paclitaxel administered over 10 days, was performed to evaluate the hematologic and non-hematologic toxicities as well as to determine the maximum-tolerated dose for the 10-day infusion duration. PATIENTS AND METHODS: Twenty-nine solid tumor patients (predominantly non-small cell lung cancer and head and neck cancer) were treated with paclitaxel at doses ranging from 5 mg/m2/day to 25 mg/m2/day administered as a 10-day continuous infusion via a pump every 21 days. Dose escalation was permitted within individual patients. Dose-limiting toxicity (DLT) was defined as grade 3 or 4 non-hematologic toxicity, ANC < or = 500 or platelet count < or = 25,000 for > or = 7 days or febrile neutropenia. The maximum tolerated dose (MTD) was defined as the highest dose level at which less than two out of six patients developed DLT. All of the patients had received prior chemotherapy; approximately two-thirds had received prior radiation as well. All patients received standard pre-medications for paclitaxel, including anti-histamines and corticosteroids. Prophylactic granulocyte colony-stimulating factor (G-CSF) was not used. RESULTS: A total of 110 courses of paclitaxel were administered to 29 patients. The incidence of hematologic and non-hematologic toxicity was quite low among the patients treated at dose levels below 17 mg/m2/day. At higher doses, non-hematologic toxicities including arthralgias, myalgias, fatigue, nausea, stomatitis, and peripheral neuropathy were seen, although nearly all of the toxicities were less than grade 3 (NCI toxicity criteria). Hematologic toxicity mostly consisted of neutropenia and was more common at dose levels of 17 mg/m2/day or higher. Nevertheless, even at the highest dose levels (21 mg/m2/day and 25 mg/m2/day) grade 3 or 4 neutropenia occurred in only 50% of patients. Dose-limiting hematologic toxicity occurred in 2 of 4 patients treated at the 25 mg/m2/day dose level. CONCLUSION: Paclitaxel can be safely administered as a 10-day infusion. The MTD for this schedule is 210 mg/m2. Unlike the 96-hour paclitaxel infusions, dose-reduction for myelosuppression may not be necessary because the MTD of paclitaxel when administered over a 10-day infusion is similar to the MTD of paclitaxel when infused over 3 or 24 hours.

Adult↗
PubMedDate not supplied

Intraliposomal chemical activation patterns of liposomal cis-bis-neodecanoato-trans-R,R-1,2-diaminocyclohexane platinum (II) (L-NDDP)-a potential antitumour agent.

L-NDDP is a liposome-entrapped platinum compound currently in phase 2 clinical trials that has been shown to undergo intraliposomal activation. The degradation/activation kinetics of liposome entrapped cis-bis-neodecanoato-trans-R,R-1,2-diamminocyclohexane platinum (II) [L-NDDP] at different conditions of pH, and temperature is presented. Liposomes were reconstituted in a solution of 0.9% sodium chloride (NaCl) in water (pH 5) at room temperature (formulation conditions currently used in the ongoing clinical trials). In the temperature experiments, L-NDDP 0.9% sodium chloride liposomes were incubated in a water-bath at 40, 60, and 80 degrees C. In the pH experiments, these solutions were compared to water, phosphate with and without chloride ion present, phosphate buffer without chloride ion at pH 3.1, 5.0, and 7.4, and glycine buffer with and without chloride ion. In 0.9% sodium chloride at room temperature, the chemical degradation/activation of liposome-bound NDDP was biphasic, with most of the degradation (approximately 45% conversion) occurring during the first hour after formation of the liposome suspension. NDDP degradation was pH dependent: when using pH 3 phosphate buffer as a reconstituting solution, liposome-bound NDDP degraded rapidly, whereas in pH 7.4 phosphate buffer it was stable for > 72 h. NDDP degradation was also temperature-dependent, the 50% point decreasing from 12 h at 25 degrees C to 9.5 h at 40 degrees C, 3.8 h at 60 degrees C, and 0.3 h at 80 degrees C when using 0.9% NaCl in water as a reconstituting solution. Using glycine buffer solution with and without NaCl at room temperature, no NDDP degradation over a 72 h period was observed at 25 degrees C; however, at 40 degrees C, only 68% NDDP remained intact at 72 h. Atomic absorption spectrophotometry (AAS) analysis of the eluting fractions after injection of L-NDDP samples reconstituted in chloride-containing and non chloride-containing solutions clearly indicated that the formation of DACH-Pt-Cl2 was only observed when chloride-containing solutions were used and was first detected at 3 h when using 0.9% NaCl in water as a reconstituting solution. These results indicate that pH and temperature, and not the presence of chloride ion, are the main factors leading to the activation of NDDP. Since 45% of NDDP is already degraded at 1 h in the same conditions, it is concluded that (1) the first active intermediates of L-NDDP formed within the liposomes are the DACH-Pt chloro-aquo and diaquo intermediates, and (2) the in vivo, antitumour activity of L-NDDP is most likely mediated by direct intracellular delivery of the active species.

Antineoplastic Agents↗
PubMedDate not supplied

Preparation and characterization of liposomes containing a lipophilic cisplatin derivative for clinical use.

Cis-bis-neodecanoato-trans-R,R-1,2 diaminocyclohexane platinum(II) (NDDP) is a lipophilic cisplatin derivative that has been formulated entrapped in multilamellar liposomes composed of dimyristoylphosphatidyl choline (DMPC) and dimyristoylphosphatidyl glycerol (DMPG). A phase I clinical study with liposome-entrapped NDDP (L-NDDP) administered i.v. every 4 weeks has been recently completed. L-NDDP was synthesized, manufactured, and reconstituted for clinical use in our laboratories. L-NDDP was prepared as a lyophilized powder containing the NDDP and the phospholipids (NDDP-lipid weight ratio 1:15; DMPC-DMPG molar ratio 7:3). The liposome suspension was obtained on the day of use just before administration to the patients by adding normal saline (final concentration 1 mg NDDP/ml) and shaking in a water-bath shaker at room temperature according to an established protocol. A total of 54 batches of lyophilized L-NDDP were prepared. Physical appearance, phospholipid content and integrity, and elemental platinum content were determined in all batches and found to be reproducible. All batches contained < 0.24 ng/ml endotoxin. The amount of residual organic solvents was < 0.05 per cent. In all reconstituted doses, drug entrapment was > 90 per cent, and the proportion of liposomes measuring > 5 microns was < 20 per cent. Our results show that reproducible batches of liposomal preparations of new compounds can be prepared in the laboratory facilities of academic institutions, thus allowing for early clinical trials with novel therapeutic agents.

Antineoplastic Agents↗
PubMedDate not supplied

Liposomes as carriers of different new lipophilic antitumour drugs: a preliminary report.

We studied the liposome formulation characteristics of eight new lipophilic antitumour agents that have demonstrated a broad spectrum of antitumour activity in preclinical in vitro and in vivo screening models. Multilamellar vesicles were prepared by using standard evaporation/hydration methods. The drug to lipid weight ratio was 1:15 in all cases. Different combinations of DMPC, DMPG and cholesterol were used. The quality of the liposomal formulations was evaluated by calculating the percentage drug bound to the liposome phase and assessing the morphology of the liposome phase by optic microscopy, to rule out the presence of drug crystals or drug/lipid microaggregates. Good liposomal preparations were obtained with hexamethylmelamine, penclomedine, mitindomide, and fazarabine. However, with taxol, batracylin, trimelamol, and diaziquone, the presence of crystals of free drug or microaggregates of lipid/drug complex was observed in all preparations, independently of lipid composition. In general, mixtures of DMPC:DMPG at a molar ratio between 7:3 and 9:1, and the addition of 5 per cent cholesterol (w/w) gave the optimal results. In vitro cytotoxicity studies of free and liposomal drugs against L1210 cells showed changes in both directions after liposome entrapment, thus suggesting that liposome entrapment may alter drug cellular uptake or may result in chemical modifications of the entrapped drug. Because of the limited number of compounds studied we were unable to identify general chemical characteristics required for an enhanced liposome formation and drug entrapment.

Animals↗
PubMedDate not supplied

Induction of senescence-like phenotype and loss of paclitaxel sensitivity after wild-type p53 gene transfection of p53-null human non-small cell lung cancer H358 cells.

The p53 gene plays an important role in the regulation of cell-cycle progression and apoptosis. Recent studies have implicated p53 in determining cell fate, and shown that p53 status is associated with cellular sensitivity to anticancer agents. However, the role of p53 in paclitaxel-induced cytotoxicity remains unclear. Here we show that the induction of exogenous wild-type (wt) p53 genes in p53-null human NSCLC H358 cells via transient gene transfection with cationic liposome-wt p53 complexes resulted in a typical senescence-like phenotype. In short, cell growth was reduced, homeostasis occurred, cell morphology became enlarged and flat, the cell cycle was arrested at G1 phase, cyclin B1 and cdc2 expression was down-regulated, and DNA synthesis was suppressed. The sensitivity of wt p53-transfected cells (H358/p53) to paclitaxel was approximately 3-fold lower than that of H358 cells. Paclitaxel treatment gradually and significantly blocked cell-cycle progression at G2/M phase and increased the accumulation of cyclin B1 and cdc2 in H358 cells. In contrast, the same treatment slightly arrested the cell cycle at G2/M phase and slightly elevated cyclin B1 expression in H358/p53 cells. The rate of uptake and efflux of paclitaxel was not significantly different between H358 and H358/p53 cells, indicating that the reduction in cellular sensitivity caused by p53 transfection was not due to alterasion in intracellular drug concentration. Together, our findings suggest that the induction of exogenous wt p53 gene expression in cells lacking p53 function can trigger the senescence program and that loss of sensitivity to paclitaxel by p53-transfected cells may be associated, at least in part, with the induction of a senescence-like phenotype.

Biological Transport↗
PubMedDate not supplied

Tissue distribution and in vivo immunosuppressive activity of liposomal cyclosporine.

The distribution and immunosuppressive activity of liposomal cyclosporine (L-CSA) when administered iv as single- and multiple-doses were compared with the commercially available cyclosporine (C-CSA) in rats. CSA concentrations in the spleen and liver were significantly greater 1 hr after dosing in rats given L-CSA compared with C-CSA. The apparent tissue to blood partition coefficient at 1 hr after dosing was significantly greater for the liver and spleen of rats treated with L-CSA compared with C-CSA. Drug concentrations 24 hr after single doses of L-CSA were significantly lower in the kidney, heart, lung, and adipose tissues compared with animals given C-CSA. Lymphocyte-blastogenic response was studied in a separate group of rats given 10 mg/kg/day of L-CSA or C-CSA for 10 days compared with drug-free control groups. A 3-fold decrease in blastogenic response was observed in rats given L-CSA compared with C-CSA-treated rats (12.7 +/- 11.8 vs. 34.9 +/- 11.3 x 10(3) dpm/10(6) cells; p less than 0.05). These data suggest that the liposomal formulation of CSA leads to enhanced tissue levels of CSA in the spleen coupled with augmentation in immunosuppressive activity.

Animals↗
PubMedDate not supplied

Cell death and DNA fragmentation induced by liposomal platinum(II) complex, L-NDDP in A2780 and A2780/PDD cells.

The effect of cisplatin and its non-cross resistant analogue, liposomal cis-bis-neodecanoato-trans-R,R-1,2-diamiconocyclohexaneplatinum (II) (L-NDDP) on inducing internucleosomal DNA fragmentation and cell death was examined in A2780 and A2780/PDD cells. In A2780 cells, both drugs were markedly effective in inducing DNA fragmentation, whereas in A2780/PDD cells, only L-NDDP produced significant DNA fragmentation, in good correlation with the observed cytotoxicity. The endonuclease inhibitor (ATA) prevented the DNA fragmentation caused by high (30-60 microM) or low (3-10 microM) concentrations of each drug in A2780 cells. In contrast, the protein synthesis inhibitor (CHX) displayed only a significant inhibitory effect on the DNA fragmentation caused by low concentrations at 48 h post-treatment. These results indicate that there are at least two different pathways leading to both drugs induced-cell death depending on drug concentrations in this cell line.

Antineoplastic Agents↗
PubMedDate not supplied

Effect of DNA topoisomerase I inhibitor, 10-hydroxycamptothecin, on the structure and function of nuclei and nuclear matrix in bladder carcinoma MBT-2 cells.

The effects of 10-hydroxycamptothecin (HCPT), a DNA topoisomerase I inhibitor, on the structure of nuclei and nuclear matrix and new DNA replication was investigated in murine bladder carcinoma MBT-2 cells. Following 10-30 min exposure of exponentially growing cells to 10-50 microM HCPT, the rate of 2 min pulse-labeling with [3H]thymidine in whole nuclei, nonmatrix, and matrix fractions was markedly decreased in a concentration- and time-dependent manner. Reduction was highest in the nuclear matrix. After treatment of cultures with 50 microM HCPT for 10 min, inhibition of DNA synthesis was 60% in the nuclear matrix and 27% in the low-salt extract fraction tended to be stimulated after drug treatment. SDS-PAGE analysis of [35S]methionine labeled proteins indicated that 50 microM HCPT decreased protein synthesis in the matrix and other nuclear subfractions. HCPT-induced ultrastructural changes in nuclei and nuclear matrix were similar to those typically associated with lesions of DNA replication or RNA transcription.

Animals↗