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Biomedical subjects

Y Fernández

Publications and source records attributed to Y Fernández.

At least 19 recordsLinked to original sources
PubMed2006

Simultaneous removal of phenol, ammonium and thiocyanate from coke wastewater by aerobic biodegradation.

A laboratory-scale activated sludge plant composed of a 20 L volume aerobic reactor followed by a 12 L volume settling tank and operating at 35 degrees C was used to study the biodegradation of coke wastewater. The concentrations of ammonium nitrogen (NH(4)(+) -N), phenols, chemical oxygen demand (COD) and thiocyanate (SCN(-)) in the wastewater ranged between 504 and 2,340, 110 and 350, 807 and 3,275 and 185 and 370 mg/L, respectively. The study was undertaken with and without the addition of bicarbonate. The addition of this inorganic carbon source was necessary to favour nitrification, as the alkalinity of the wastewater was very low. Maximum removal efficiencies of 75%, 98% and 90% were obtained for COD, phenols and thyocianates, respectively, without the addition of bicarbonate. The concentration of ammonia increased in the effluent due to both the formation of NH(4)(+) as a result of SCN(-) biodegradation and to organic nitrogen oxidation. A maximum nitrification efficiency of 71% was achieved when bicarbonate was added, the removals of COD and phenols being almost similar to those obtained in the absence of nitrification. Batch experiments were performed to study the influence of pH and alkalinity on the biodegradation of phenols and thiocyanate.

Aerobiosis↗
PubMed2006

Study of the aerobic biodegradation of coke wastewater in a two and three-step activated sludge process.

A laboratory-scale biological plant composed of two aerobic reactors operating at 35 degrees C was used to study the biodegradation of coke wastewater. The main pollutants to be removed are organic matter, especially phenols, thiocyanate and ammonium nitrogen. The concentrations of the main pollutants in the wastewater during the study ranged between 922 and 1,980 mg COD/L, 133 and 293 mg phenol/L, 176 and 362 mg SCN/L and 123 and 296 mg NH(4)(+)-N/L. The biodegradation of these pollutants was studied employing different hydraulic residence times (HRT) and final effluent recycling ratios in order to minimize inhibition phenomena attributable to the high concentrations of pollutants. During the optimisation of the operating conditions, the removal of COD, phenols and thiocyanate was carried out in the first reactor and the nitrification of ammonium took place in the second. The best results were obtained when operating at an HRT of 98 h in the first reactor and 86 h in the second reactor, employing a recycling ratio of 2. The maximum removal efficiencies obtained were 90.7, 98.9, 98.6 and 99.9% for COD, phenols, thiocyanate and NH(4)(+)-N, respectively. In order to remove nitrate, an additional reactor was also implemented to carry out the denitrification process, adding methanol as an external carbon source. Very high removal efficiencies (up to 99.2%) were achieved.

Bioreactors↗
PubMed2006

Removal of ammonium from aqueous solutions with volcanic tuff.

This paper presents kinetic and equilibrium data concerning ammonium ion uptake from aqueous solutions using Romanian volcanic tuff. The influence of contact time, pH, ammonium concentration, presence of other cations and anion species is discussed. Equilibrium isotherms adequately fit the Langmuir and Freundlich models. The results showed a contact time of 3h to be sufficient to reach equilibrium and pH of 7 to be the optimum value. Adsorption capacities of 19 mg NH(4)(+)/g were obtained in multicomponent solutions (containing NH(4)(+), Zn(2+), Cd(2+), Ca(2+), Na(2+)). The presence of Zn and Cd at low concentrations did not decrease the ammonium adsorption capacity. Comparison of Romanian volcanic tuff with synthetic zeolites used for ammonium removal (5A, 13X and ZSM-5) was carried out. The removal efficiciency of ammonium by volcanic tuff were similar to those of zeolites 5A and 13X at low initial ammonium concentration, and much higher than those of zeolite ZSM-5.

Adsorption↗
PubMed2005

Anaerobic treatment of sludge from a nitrification-denitrification landfill leachate plant.

The viability of anaerobic digestion of sludge from a MSW landfill leachate treatment plant, with COD values ranging between 15,000 and 19,400mg O(2)dm(-3), in an upflow anaerobic sludge blanket reactor was studied. The reactor employed had a useful capacity of 9l, operating at mesophilic temperature. Start-up of the reactor was carried out in different steps, beginning with diluted sludge and progressively increasing the amount of sludge fed into the reactor. The study was carried out over a period of 7 months. Different amounts of methanol were added to the feed, ranging between 6.75 and 1cm(3)dm(-3) of feed in order to favour the growth of methanogenic flora. The achieved biodegradation of the sludge using an upflow anaerobic sludge blanket Reactor was very high for an HRT of 9 days, obtaining decreases in COD of 84-87% by the end of the process. Purging of the digested sludge represented approximately 16% of the volume of the treated sludge.

Anaerobiosis↗
PubMed2005

Removal of Cd and Zn from inorganic industrial waste leachate by ion exchange.

This paper presents a study of the removal of Cd and Zn present in the leachate from an inorganic industrial waste landfill using cationic exchange resins (Amberlite 200, 252-C, IR-120, Duolite C-464), a chelating resin, Amberlite IRC 718, and an adsorbent resin, XAD-2. The chelating resin Amberlite IRC 718 presented the higher removal in batch experiments for both metals (93% for Zn and 50% for Cd). Five hundred ten bed volumes of leachate were treated in column experiments using this material, reducing the concentrations of Cd and Zn from 18 mg/dm3 to 0.1 and 1.0mg/dm3, respectively. Regeneration of the saturated bed was achieved with 11 BV of 2M HCl.

Adsorption↗
PubMed2004

Biweekly paclitaxel plus gemcitabine in advanced breast cancer: phase II trial and predictive value of HER2 extracellular domain.

BACKGROUND: We wanted to assess the toxicity and efficacy of paclitaxel plus gemcitabine in advanced breast cancer and to confirm whether circulating HER2 extracellular domain (ECD) correlates with treatment response. PATIENTS AND METHODS: Forty-three patients received paclitaxel 150 mg/m2 followed by gemcitabine 2500 mg/m2, both on day 1 of 14-day cycles, with a maximum of eight cycles. Serum levels of HER2 ECD were assessed by ELISA. RESULTS: All patients were evaluable for toxicity and 42 for efficacy. Overall toxicity was low. Grade 3 neutropenia occurred in 12% of patients and grade 4 in 17%, and other grade 3 toxicities in <5%. One patient had an allergic infusion reaction. Overall response rate was 71% [95% confidence interval (CI) 62% to 81%], with 11 patients achieving a complete response (26%). With a median follow-up of 26 months, the median time to progression was 16.6 months. Response rate correlated significantly with HER2 ECD, with 42% of HER2 ECD-positive patients responding versus 83% of HER2 ECD-negative patients (P = 0.02). Furthermore, response duration was shorter in patients with positive HER2 ECD levels (7.9 versus 14.4 months; P = 0.04). CONCLUSIONS: Paclitaxel plus gemcitabine given as an every 2-weeks schedule is a well tolerated and active regimen in advanced breast carcinoma. This is an attractive combination to use when anthracyclines are not indicated, such as in HER2 positive cases that receive trastuzumab. In addition, elevated levels of HER2 ECD adversely affect the efficacy of treatment.

Adenocarcinoma↗
PubMed2003

Prospective randomised phase II study of docetaxel versus paclitaxel administered weekly in patients with non-small-cell lung cancer previously treated with platinum-based chemotherapy.

BACKGROUND: Docetaxel and paclitaxel have activity in the second-line treatment of non-small-cell lung cancer (NSCLC), and can be administered as weekly schedules. This phase II randomised study was designed to test the efficacy and toxicity of both taxanes in patients with NSCLC previously treated with platinum-based chemotherapy. PATIENTS AND METHODS: Patients (n = 71) with documented NSCLC were randomised to receive docetaxel (n = 35 patients; 36 mg/m(2)) or paclitaxel (n = 36 patients; 80 mg/m(2)) as a 1 h weekly infusion for 6 weeks followed by a 2-week rest. The cycles were repeated until disease progression or non-acceptable toxicities occurred. RESULTS: Treatment achieved partial response of one versus five patients, median time-to-progression of 74 versus 68 days, and overall survival of 184 versus 105 days, with docetaxel and paclitaxel, respectively. The most common non-haematological toxicities were (docetaxel versus paclitaxel): grade 3/4 pulmonary toxicity in seven versus one patient; grade 2/3 diarrhoea in nine versus five; and grade 3/4 haematological toxicities occurred in two versus four patients. There were no treatment-related deaths. CONCLUSIONS: Docetaxel and paclitaxel administered weekly have discrete efficacy in patients with NSCLC previously treated with platinum-based chemotherapy. The higher non-haematological toxicity of docetaxel, particularly pulmonary toxicity and diarrhoea, is of concern and warrants further investigation.

Adult↗
PubMed2001

Metastatic behavior of human breast carcinomas overexpressing the Bcl-x(L) gene: a role in dormancy and organospecificity.

The ability of metastatic cells to survive antiapoptotic signals may contribute to the organospecific-spread patterns of clinical metastasis and dormancy. MDA-MB-435 breast cancer cells (435/Bcl-x(L)), which overexpress the Bcl-x(L) gene, were labeled with the luciferase gene and injected orthotopically into homozygous athymic Balb/c (nude) mice to study the metastatic behavior of the breast cancer cells. The overexpression of Bcl-x(L) in tumors increased the overall metastatic burden in mice (bones, liver, kidneys, brain, lungs, and lymph nodes) in comparison with control tumors (435/NEO:luc) during the same time interval (ANOVA, p = 0.005). The principal differences after 110 days were found in bones, which had 1.5 x 10(5) +/- 1.2 x 10(5) tumor cell equivalents (p = 0.03), and lymph nodes, which had 7.0 x 10(6) +/- 6.0 x 10(6) tumor cell equivalents (p = 0.08). The analyses of light production by tissues at different times showed that cells from 435/NEO:luc and 435/Bcl-x(L).luc tumors were detectable in several organs by the second day after intramammary fat pad implantation. Although initially arriving at the target organs in similar numbers, 435/Bcl-x(L) cells developed more metastases than 435/Neo cells, indicating that the Bcl-x(L) gene might have a role in breast cancer dormancy, promoting survival of cells in metastatic foci. Thus, we suggest that overexpression of Bcl-x(L) could counteract the proapoptotic signals in the microenvironment and favor the successful development of metastasis in specific organs.

Analysis of Variance↗
PubMed2000

Bcl-xL promotes metastasis of breast cancer cells by induction of cytokines resistance.

Metastasis is a highly complex process involving the survival of tumor cells, both in the blood stream and within specific organs. Cell-death and survival are determined by a number of gene products from an expanding family of the Bcl-2 gene, either promoting or preventing apoptosis. Furthermore, the survival of tumor cells may favor the accumulation of additional genetic alterations causing further growth and invasive opportunities which may lead to metastasis. To examine whether the prevention of cell-death influences the metastatic behavior, we transfected a human breast cancer cell line MDA-MB-435 with the Bcl-xL cDNA and then studied metastatic ability of the selected clones in vivo. Our results show that Bcl-xL-clones had a decreased tumor growth latency and an increased metastatic ability. Apoptosis-resistance to cytokines was induced in 435 cells by Bcl-xL-expression with minor modifications in their proliferation rates. These cells also showed diminished adhesion to extracellular matrix proteins and a survival advantage in suspension over 435/Neo cells. Moreover, to determine survival in blood stream and in cells lodged in the lungs, we injected 435/Bcl-xL and 435/Neo cells at 1:3 proportion i.v., and animals were killed at intervals of 15' to 16 h after injection. Tumor cells were recovered from the lungs and Southern-blot analysis revealed the presence of exogenous Bcl-xL cDNA. These results showed that 435/Bcl-xL cells had a survival advantage in circulation over 435/Neo cells. This advantage in vivo was attributable to Bcl-xL expression. We conclude that Bcl-xL expression in breast cancer cells can increase metastatic activity. This advantage could be created by inducing resistance to apoptosis against cytokines, increasing cell survival in circulation, and enhancing anchorage-independent growth.

Animals↗
PubMed2000

Paclitaxel/gemcitabine administered every two weeks in advanced breast cancer: preliminary results of a phase II trial.

The purpose of this study was to evaluate the toxicity and efficacy of paclitaxel/gemcitabine administered every 2 weeks in the first-line treatment of advanced breast cancer. Forty-three chemonaive patients with histologically confirmed metastatic breast carcinoma were enrolled. Patients received paclitaxel 150 mg/m2 followed by gemcitabine 2,500 mg/m2, both on day I of a 14-day cycle, for a maximum of eight cycles. Thirty-four patients were evaluable for toxicity; 38 were evaluable for efficacy. The median age at the time of diagnosis was 54 years, the median performance status was 90, and the median number of lesions was three. Most patients (71%) had received prior adjuvant therapy. Grade 3 and 4 toxicity was limited to leukocytes (14% and 18%, respectively). Grade 3 toxicities (5% each) were thrombocytopenia, nausea and vomiting, elevation of aspartate transaminase, neurosensory, and constipation. One patient had neutropenia and fever. The objective response rate was 68% (21% complete response and 47% partial response); 18% had stable disease and 13% had partial disease. The preliminary evaluation of paclitaxel/gemcitabine given as a 2-week schedule to patients with untreated advanced breast carcinoma shows encouraging activity and a favorable toxicity profile.

Adult↗
PubMed1997

Uracil and tegafur modulated with leucovorin: an effective regimen with low toxicity for the treatment of colorectal carcinoma in the elderly. Oncopaz Cooperative Group.

BACKGROUND: In spite of the high prevalence of cancer in the elderly, little information is available about the efficacy and toxicity of chemotherapy in elderly patients. In a previous study, the authors demonstrated that the combination of uracil and tegafur (UFT) with leucovorin (LV) was active and well tolerated in patients with advanced colorectal carcinoma (ACC). The objective of the current study was to determine the efficacy and toxicity of this regimen in elderly patients with ACC. METHODS: Thirty-eight unselected patients older than 70 years (median age, 74 years) with measurable ACC were included. All patients were evaluable for toxicity and response. The regimen consisted of intravenous LV 500 mg/m2 on Day 1, oral LV 15 mg every 12 hours on Days 2-14, and oral UFT 390 mg/m2 on Days 1-14. Treatment was repeated every 28 days for a minimum of 4 courses per patient. RESULTS: Two hundred eighty-eight cycles of chemotherapy were delivered (median, 7 per patient). Two patients (5%) achieved a complete response and 9 (24%) a partial response, for an overall response rate of 29%. Toxicity was mild, without dose-limiting myelosuppression. Four patients (10%) experienced Grade 3-4 diarrhea, 1 patient had Grade 3-4 nausea/vomiting, and 1 had Grade 3-4 mucositis. Grade 3-4 toxicity was more frequent among women than men (38% vs. 4%, P < 0.05). CONCLUSIONS: Treatment with oral UFT modulated with LV is effective, well tolerated, and feasible on an outpatient basis for elderly patients with ACC. However, elderly women should be followed closely for the early detection of toxicity.

Administration, Oral↗
PubMed1995

[Evaluation of biological fish silage in broiler chicken].

Biological fish silage was produced from the mixture of three low price fish species. After mixing it with molasse, papaya and pineapple wastes, and Lactobacillus plantarum incoculation, the product was stored for seven days, dehydrated and added to several diets of formulated poultry feed as a substitute of fish meal. Physical-chemical and microbiological analyses were done to the raw materials and final products. Biological tests of acceptability indicated that chicken preferred diets up to 50% of fish silage. Chicken's weigh increased and food consumption tests, in addition to the sensory evaluation tests in the chickens white meat, showed the advantages of inclusion of 5-20% fish silage in the diets of experimental animals.

Animals↗
PubMed1993

Transcranial oblique lateral radiography to verify the position of the mandibular condyles with the use of functional appliances.

By means of standardized transcranial oblique lateral (TOL) radiographs, the position of the mandibular condyles in the glenoid fossae of 14 patients with Class II division 1 malocclusion was studied at the beginning of treatment with or without functional appliances placed in position, and also at the end of treatment. A significant increase in the distance between the upper point of the condyle and the glenoid fossa was found when the appliance was worn for the first time. This displacement was found to disappear at the end of the treatment even when the appliance was placed in position.

Activator Appliances↗