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Biomedical subjects

M A Gómez

Publications and source records attributed to M A Gómez.

At least 19 recordsLinked to original sources
PubMed2006

Biological nitrogen and phenol removal from saline industrial wastewater by submerged fixed-film reactor.

In this study a biological nitrogen removal process using a submerged fixed-film reactor was applied to treat industrial wastewater with phenol (1g/l), a high nitrogen concentration (0.4 g N/l) and high salinity (30 g/l). The process consisted of a pre-denitrification system with a down-flow-up-flow biofilter (two columns, each with an effective volume of 21 l) packed with clayey schists from recycled construction material. The efficiency of the system for reducing COD, phenol concentration and total nitrogen was tested under different running conditions such as influent flow (10, 12 and 15 l/d), air loading (6.8 and 13.6m(3)/m(2)h) and effluent recirculation (300%, 400%, and 600%). The system demonstrated a high capacity for reducing COD concentration (95.75+/-0.72%), independently of running conditions. The aerobic column eliminated most of the phenol in the influent. Nitrogen removal took place mainly in the anoxic column, and was conditioned by the air loading in the aerated column, owing to the dependence of nitrification on the supply of oxygen. However, this process was not able to achieve a nitrogen oxidation superior to 63%, in spite of a sufficient supply of oxygen and the diluting effect of high recirculation (600%) on the phenol concentration in the influent. In spite of the limitations observed in the process of nitrification, results for the removal of total nitrogen were as high as 83%, owing to a combination of different processes for nitrogen removal.

Biofilms↗
PubMed2006

Morbidity and mortality in liver retransplantation.

INTRODUCTION: The incidence of orthotopic liver retransplantation (re-OLT) ranges from 6% to 11%. The most frequent causes of early re-OLT are allograft failure, uncontrolled acute rejection, and vascular complications. MATERIALS AND METHODS: A retrospective study of 512 orthotopic liver transplants (OLTs) in 482 patients over 15 years. RESULTS: The incidence of re-OLT was 6.6%, with a higher percentage of men requiring re-OLT than first-time OLT (75.0% vs 63.0%, P < .05). The reasons for re-OLT were thrombosis 21.7%, aneurysm 6.5%, stenosis 3.2%, primary nonfunction (PNF) 21.7%, and chronic rejection or recurrence of the initial disease 40.4%. Complications included PNF (22.0%), acute renal failure (65.6%), postoperative infection (87.5%), and adult respiratory distress syndrome (9.4%; P < .05). No differences were seen in the incidence of septicemia or postoperative hemorrhage. The average survival was much lower in re-OLT (21.8 days) compared with OLT (194.5 days; P < .05). The mortality rates in re-OLT were 100% for primary biliary cirrhosis, 85.7% for HCV, 50% for alcoholic cirrhosis, and 20% for HBV. A direct association between the Model for End-stage Liver Disease (MELD) score and the number of complications was present. DISCUSSION: There was a greater requirement for re-OLT in men and those patients transplanted due to hepatitis B virus cirrhosis and fulminant hepatitis (P < .05). The re-OLT patients had no greater incidence of sepsis compared with the OLT patients, although they did have a greater incidence of primary graft dysfunction, acute renal failure, adult respiratory distress syndrome, and postoperative infection (P < .05). The MELD was a good parameter for predicting graft evolution. Re-OLT in patients with primary biliary cirrhosis and hepatitis C virus was associated with a high degree of mortality.

Humans↗
PubMed2006

[Intimal sarcoma of the pulmonary artery: a rare cause of pulmonary hypertension].

Intimal sarcoma of the pulmonary artery is a rare tumor that is usually diagnosed during surgery or autopsy. Such tumors are characterized by local growth, with only slight ability to metastasize. Diagnosis is difficult and often delayed owing to the nonspecific nature of the symptoms. Since intimal sarcoma of the pulmonary artery is so rare and insidious it is often confused with pulmonary thromboembolism and is therefore treated inappropriately with prolonged anticoagulation or thrombolysis. With a mean survival of 12 months from the onset of symptoms, the prognosis is poor. We present the case of a woman who was preoperatively diagnosed with intimal sarcoma of the pulmonary artery and who underwent surgical resection with no apparent recurrence at long term follow-up. A review of the literature is also included.

Female↗
PubMed2005

Influence of inocula over start up of a denitrifying submerged filter applied to nitrate contaminated groundwater treatment.

Pure culture of denitrifying bacteria isolated from heterogeneous biofilm was applied as inocula to a submerged filter for removing nitrogen from contaminated groundwater. Five highly denitrifying bacteria were used, comparing their attachment, nitrogen-removal ability and final water quality in the start up of the system. Our experiments showed that inocula selection is the crucial step when the submerged filter is applied to obtain drinking water, since selected strains vary in their ability to colonise support material and to remove nitrogen, and in their effect on treated water quality during start up phase. Hidrogenophaga pseudoflava strain proved to be the most suitable inoculum out of the five tested, under the experimental conditions.

Bacteria↗
PubMed2005

Inoculation of a submerged filter for biological denitrification of nitrate polluted groundwater: a comparative study.

Activated sludge from a wastewater treatment plant and pure culture of Hydrogenophaga pseudoflava were utilized for the development of a denitrifying biofilm in a submerged filter in order to remove nitrate from polluted groundwater. Nitrate removal efficiency, nitrite accumulation, turbidity, COD and faecal indicators persistence in the treated water were determined at different superficial hydraulic loading (10, 20 and 30 m(3)/m(2) d) and superficial nitrate loading rates (1, 2, 3, 6 and 9 Kg NO(3)(-)/m(2) d) in the submerged filter. The application of H. pseudoflava as inocula allowed better results in terms of system stability, higher superficial hydraulic loading and superficial nitrate loading rates (30 m(3)/m(2)d and 9 kg NO(3)(-) /m(2) d, respectively). These values improve those obtained when the system was inoculated with activated sludge. In addition, the pure microbial inocula improved design parameters and running of the process due to its biofilm homogeneity, obtaining treated water with better characteristics to its final use as drinking water than that obtained with an activated sludge inocula.

Biofilms↗
PubMed2005

Mycotic pseudoaneurysms after liver transplantation.

The most frequent etiology of visceral artery aneurysms is arteriosclerosis, but vascular manipulation during hepatic transplantation may also cause a mycotic pseudoaneurysm. Treatment with embolization, stents or percutaneous thrombin injection have been recommended but surgical revascularization is indicated when interventional techniques fail. A 43-year-old man with hepatitis C virus cirrhosis who underwent orthotopic liver transplantation from a cadaveric donor was treated with cyclosporine, mycophenolate, and steroids and was discharged from hospital at 35 days. Two months later he was readmitted with a febrile syndrome. Abdominal computed tomography showed necrosis of hepatic segments IV, V, and VI. Magnetic resonance imaging and angiography revealed partial thrombosis of the hepatic artery and stenosis of the portal anastomosis secondary to an aneurysm of the hepatic artery. A few hours after the radiological diagnosis, the patient suffered a bout of upper gastrointestinal bleeding and shock. Emergency surgery revealed a mycotic pseudoaneurysm of the common hepatic artery, which had ruptured into the bile tract with hemobilia. The liver graft was removed because of severe necrosis of the right liver. The patient died awaiting a new liver transplantation.

Adult↗
PubMed2005

Wastewater treatment using fibrist and saprist peat: a comparative study.

Two different peat types (fibrist and saprist) were compared to examine their respective wastewater treatment capacity in peat beds under different hydraulic loadings (1.8, 1.2, 0.9, and 0.6 m3/m2 d) and pollutant loadings (dependent on influent quality). The comparative study was carried out on a pilot scale using urban wastewater which had undergone preliminary treatment. The systems were observed to retain a higher quantity of suspended solids when the load was higher, regardless of the hydraulic loading and the type of peat employed. System performance with respect to BOD was similar to that observed for COD, and it was noted that the capacity to retain organic matter decreased when the hydraulic loading or pollutant loading was increased. This effect was observed in both peats but to different degrees, being lower in the case of saprist peat. The results indicate that it would be necessary to work with low hydraulic loadings in order to comply with legislative requirements on effluent. Peat beds are therefore suitable for implementation in small population centers, where the system's efficiency partly depends on the type of peat employed. In view of the system's performance with respect to suspended solids, this technology may be considered a good primary treatment, and could be usefully combined with other processes aimed at eliminating dissolved organic matter.

Adsorption↗
PubMed2004

Quantitative pp65 antigenemia in the diagnosis of cytomegalovirus disease: prospective assessment in a cohort of solid organ transplant recipients.

OBJECTIVES: To assess the accuracy of quantitative pp65 antigenemia (pp65Ag) in the diagnosis of CMV disease, in a cohort of solid-organ transplant recipients. METHODS: Prospective observational study during the first 6 months following transplantation, with determination of pp65Ag at weeks 2, 4, 6, 8, 10, 11, 12, 14 and 16. Sensitivity (S), specificity (E), positive and negative predictive values (PPV, NPV), and the optimal cut-off point for diagnosing CMV disease, were determined. RESULTS: The cohort consisted of 35 liver, 26 renal and 12 heart graft recipients. Thirteen (17.2%) were seronegative and received a seropositive graft. Of 583 blood samples, pp65Ag was positive in 109 (18.7%) from 37 patients (51%). Twenty-two patients developed CMV disease (0.3 episodes/patient); gastrointestinal disease was the most frequent (15 episodes), followed by viral syndrome (3 episodes). Patients with positive pp65Ag had a relative risk for CMV disease of 6.19 [IC95%=1.99-19.04], (P=.0001). Diagnostic values of pp65Ag were: S=86%, E=65%, PPV=51%, NPV=92%. The cut-off of > or =10 infected cells/10(5), at weeks 2, 4, 6 and 8 obtained the best PPV (0, 67, 91 and 54%), and NPV (47, 52, 67 and 50%). CONCLUSIONS: In the studied population, the presence of positive pp65Ag was associated with a high risk of developing CMV disease, and the most useful cut-off point for the diagnosis was > or =10 infected cells/10(5).

Adult↗
PubMed2004

Chronic cyclosporine-induced nephrotoxiciy in heart transplant patients: long-term benefits of treatment with mycophenolate mofetil and low-dose cyclosporine.

BACKGROUND: Cyclosporine-induced nephropathy is a major limitation in heart transplant patients. Cyclosporine dose reduction may lead to substantial early improvement in renal function. Our aim was to study the long-term benefits of therapy with low doses of cyclosporine plus mycophenolate mofetil in heart transplant patients with drug-induced nephrotoxicity. METHODS: Twenty-five adult heart transplant patients with cyclosporine-related nephrotoxicity (mean posttransplant = 41.7 +/- 25.7 months) were included in the retrospective analysis (22 men, mean age = 58.8 +/- 7.9 years.). Patients were switched from azathioprine to mycophenolate mofetil (1 to 3 g/d), followed by a stepwise reduction in cyclosporine dosage (trough cyclosporine level maintained around 100 ng/mL). Renal function was determined by serial measurements of serum creatinine and glomerular filtration rate at 3-month intervals. RESULTS: With a mean follow-up of 30 +/- 13 months, the baseline creatinine of 2.37 +/- 0.5 mg/dL decreased to 1.59 +/- 0.40 mg/dL (P < .0001). The baseline glomerular filtration rate of 36.77 +/- 10.10 mL/min improved to 54.98 +/- 13.80 mL/min (P < .0001). The cyclosporine level was the unique independent variable associated with renal functional improvement (partial R(2) = 0.4). Within the first 3 months, renal function displayed a rapid improvement after conversion to mycophenolate mofetil (P < .001), reaching a plateau, without further significant improvement over the course of time. CONCLUSIONS: Cyclosporine-induced nephrotoxicity is not a progressive, irreversible disease. Reduction in cyclosporine exposure by addition of mycophenolate mofetil is useful to achieve long-term renal functional improvement, thereby avoiding chronic renal failure. A unique, significant factor associated with this improvement was the reduction in cyclosporine level.

Adult↗
PubMed2004

Phase I/II trial of irinotecan plus high-dose 5-fluorouracil (TTD regimen) as first-line chemotherapy in advanced colorectal cancer.

BACKGROUND: We conducted a phase I/II study of weekly irinotecan [30 min intravenous (i.v.) infusion] combined with 5-fluorouracil (5-FU 3 g/m(2) weekly 48 h i.v. infusion, TTD regimen) as first-line chemotherapy for patients with advanced colorectal cancer (CRC). PATIENTS AND METHODS: The maximum tolerated dose (MTD) and the dose-limiting toxicity (DLT) in the treatment of gastrointestinal solid tumors (in phase I), and the antitumor activity and toxicity of the recommended phase I dose (in phase II) were determined. RESULTS: Diarrhea was the DLT, and irinotecan 80 mg/m(2) plus 5-FU 3 g/m(2) was the recommended phase I dose. In phase II, the confirmed response rate was 44% [95% confidence interval (CI) 29% to 59%] and the median overall survival was 23.8 months. However, grade 3/4 diarrhea affected 59% of patients and led to withdrawal of three patients. A second cohort of patients studied using the same schedule but with a reduced 5-FU starting dose of 2.25 g/m(2) showed improved tolerance (the incidence of grade 4 diarrhea decreased from 28% to 11% and overall grade 3/4 diarrhea to 56%, with no patient withdrawals) but the confirmed response rate was 28% (95% CI 14% to 45%) and median overall survival was 17.2 months. CONCLUSIONS: We found weekly irinotecan 80 mg/m(2) plus TTD regimen (5-FU 2.25 g/m(2) given as 48-h i.v. infusion) to be a feasible and active combined chemotherapy for the first-line treatment of advanced colorectal cancer.

Adult↗
PubMed2003

Influence of hydraulic loading and air flowrate on urban wastewater nitrogen removal with a submerged fixed-film reactor.

Nutrient disposal to sensitive areas, particularly nitrogen and phosphorus from wastewater treatment plants, provokes eutrophication reducing water quality. Fixed film technology is widely used for the removal of organic matter and nitrogen by the biological process of nitrification-denitrification. This paper studies a nitrification and post-denitrification lab-scale plant with a downflow aerobic submerged filter for removal of organic matter and nitrification, followed by an anoxic upflow biofilter for denitrification. Recycled construction material (clay shists) was employed as support material and methanol was used as carbon source. After 2 weeks of acclimation in which nitrification reached steady-state conditions, different hydraulic loadings (0.35-1.59 m(3)/m(2)h) and air flowrates (7.78-43.5 m(3)/m(2)h) were applied for 1 year. The highest hydraulic loading which complied with the EU regulation on nitrogen disposal was 0.71 m(3)/m(2)h (1.6 h). Hydraulic retention time (HRT), which corresponded to a nitrogen removal of 0.64 kg N/m(3) per day operating at an air flowrate of 25.6 m(3)/m(2)h. Concerning to organic matter removal efficiency, the aerobic reactor accepted a maximum chemical oxygen demand (COD) volumetric loading of 16.0 kg COD/m(3) per day with a 75% COD removal efficiency. For all the tests carried out, suspended solids (SS) concentration in the outlet water was less than 35 mg/l.

Bacteria, Aerobic↗
PubMed2003

Successful heart transplantation in patients with inherited myopathies associated with end-stage cardiomyopathy.

UNLABELLED: Inherited myopathies in patients with secondary end-stage cardiomyopathies have always been considered a relative contraindication for cardiac transplantation. High operative risk related to muscle impairment and potential graft involvement secondary to the underlying myopathy have been the two main reasons implicated in the poor prognosis. OBJECTIVE: The aim of this study was to evaluate the outcome in patients who underwent cardiac transplantation in our hospital due to end-stage cardiomyopathy secondary to inherited myopathies. METHODS: Among 311 patients who underwent heart transplantation in our hospital, five (2%) had end-stage cardiomyopathies related to inherited myopathies. Four patients had muscular dystrophy (three Becker's muscular dystrophy and one hips-dystrophy) and the fifth desminopathy. In one patient cardiomyopathy was the initial manifestation of the disease. Mean age at the time of transplantation was 38.6 years (range from 24 to 55). The mean follow-up after transplantation was 57.4 months (range from 13 to 128). The intraoperative and postoperative course of these individuals did not show higher complication rates than other patients. All recipients experienced successful rehabilitation; no evidence of graft dysfunction has been detected during follow-up. All of them are alive with a good performance status. CONCLUSIONS: In our experience, patients who underwent heart transplantation due to end-stage cardiomyopathy secondary to inherited myopathy with only a mild degree of muscle impairment did not display higher postoperative nor long-term complications compared to other recipients.

Adolescent↗
PubMed2003

Results of an upper endoscopy protocol in liver transplant candidates.

OBJECTIVE: our aims is to understand endoscopic findings from a preoperative systematic study of patients with hepatic cirrhosis who were candidates for transplantation and their impact on a protocol for primary and secondary prophylaxis of variceal haemorrhage. PATIENTS AND METHODS: this study involves a retrospective evaluation of upper digestive tract lesions detected before inclusion and a prospective evaluation of new episodes of variceal haemorrhage, associated mortality rates, and factors that are likely to be involved in the development of this condition. Primary prophylaxis with beta-blockers was considered indicated in cases of varices of grande II or greater or with signs associated with increased risk. Secondary prophylaxis was essentially always associated with medical and endoscopic treatment. RESULTS: of 134 patients, there were 9 deaths, with a median time on the waiting list of 3 months. Of all patients, 33.6% presented with high risk oesophageal varices, 11.2 % with gastric varices, 42.6% with portal hypertensive gastropathy, and 26.9% with peptic lesions. Primary prophylaxis was indicated in 33 of 90 patients, and was initiated in almost half of the cases as a results of the study. Optimum fulfiment of the pre-established objectives was 75.3%. The incidence of new haemorrhagic events due to varices was 10.4% and accounted for almost half of the deaths during the monitoring period. The only statistically significant predictive factors were the presence of gastrict varices and previous history. CONCLUSION: upper endoscopy should play a role in the preoperative examination of liver transplant candidates due to the significant impact it has on subsequent management.

Esophageal and Gastric Varices↗
PubMed2002

Effect of dissolved oxygen concentration on nitrate removal from groundwater using a denitrifying submerged filter.

A unidirectional submerged filter system was employed to purify groundwater contaminated with nitrate by biological denitrification. The influence of the concentration of dissolved oxygen (DO) in the process was tested using ethanol, methanol and sucrose as carbon sources. Inorganic-nitrogen removal, growth of the biofilm, platable denitrifying bacteria and nitrate reducing bacteria in biofilm were studied. With regard to the type of electron donor used, the presence of oxygen decreased the removal efficiency of inorganic nitrogen and caused an increase of nitrite concentration in the treated water. These negative effects depended on utilised carbon source. Biological denitrification with alcohols such as ethanol and methanol was less affected by DO than with sucrose. The development of the biofilm was also influenced by the DO concentration as excess O(2) caused reduced biofilm growth. These biofilms developed in oxygen presence had a smaller bacterial density and a lower denitrifying bacteria versus nitrate reducing bacteria ratio, which led to an unfavorable inorganic nitrogen removal and presence of nitrite in the treated water. All these effects are more pronounced when sucrose is used as carbon source.

Bacteria↗