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Biomedical subjects

L Calvo

Publications and source records attributed to L Calvo.

At least 19 recordsLinked to original sources
PubMed2007

Detoxification of kraft pulp ECF bleaching effluents by catalytic hydrotreatment.

Two different effluents from the D(1) and E(1) stages of the ECF bleaching of Eucalyptus globulus kraft pulp were treated by catalytic hydrogenation in a trickle bed reactor using commercial and homemade Pd/AC catalysts. The reactor was fed with the bleaching effluent and a H(2)/N(2) gas stream. The variables studied were space-time (1.4-5g(cat)min/mL), gas to liquid flow ratio (286-1000vol.), gas feed concentration (H(2):N(2), 1:1-1:7.3vol.), temperature (25-100 degrees C) and pressure (1-11bar). Hydrotreatment performance was evaluated in terms of ecotoxicity, adsorbable organic halogen (AOX), chemical oxygen demand (COD), biological oxygen demand (BOD(5)) and colour removal. In all the runs, the ecotoxicity of the effluents decreased as a result of the treatment, achieving reductions that ranged from 70% to 98%. Simultaneously to the reduction of toxicity, the hydrotreatment led to a decrease of the colour of the effluents, being the decrease significantly higher in the case of E(1) effluent. The AOX content was reduced by 85% and 23% for E(1) and D(1) effluents, respectively. In the case of D(1) effluent the removal of ecotoxicity was significantly higher than that of AOX, which indicates that much of the toxicity of the effluent must be associated to non-chlorinated organics. In spite of the important reduction of ecotoxicity, the biodegradability of the effluents only increased slightly. The homemade catalysts, prepared from activated carbons with a high external or non-microporous surface area and mesopore volume and a convenient surface chemistry showed a higher efficiency than the commercial one.

Biodegradation, Environmental↗
PubMed2006

A kinetic study of isoamyl acetate synthesis by immobilized lipase-catalyzed acetylation in n-hexane.

The objective of this work was to propose a reaction mechanism and to develop a rate equation for the synthesis of isoamyl acetate by acylation of the corresponding alcohol with acetic anhydride using the lipase Novozym 435 in n-hexane. The reaction between isoamyl alcohol and acetic anhydride occurred at high rate in first place. Then, if excess alcohol was used, produced acetic acid further reacted with remaining alcohol, leading to yields higher than 100% (based on initial acetic anhydride content). This reaction was much slower and took place only when acetic anhydride had been totally consumed. Optimal pH for Novozym 435 was 7.7. Acetic acid strongly inactivated the enzyme but it was partially caused by the pH drop in the biocatalyst aqueous microenvironment. Acetic anhydride also showed an important inhibition effect. On the contrary, isoamyl alcohol and isoamyl acetate had no negative effect on the lipase. The analysis of the initial rate data showed that reaction followed a Ping-Pong Bi-Bi mechanism with inhibition by acetic anhydride. The kinetic constants were obtained by multiple regression analysis of experimental findings. Equation predictions and experimental reaction rate values matched very well at conditions where acetic acid concentration in the medium was low.

Acetic Acid↗
PubMed2006

Toxicity and health-related quality of life in breast cancer patients receiving adjuvant docetaxel, doxorubicin, cyclophosphamide (TAC) or 5-fluorouracil, doxorubicin and cyclophosphamide (FAC): impact of adding primary prophylactic granulocyte-colony stimulating factor to the TAC regimen.

BACKGROUND: The aim of the study was to analyse the toxicity and health related quality of life (HRQoL) of breast cancer patients treated with FAC (5-fluorouracil, doxorubicin, cyclophosphamide) and TAC (docetaxel, doxorubicin, cyclophosphamide) with and without primary prophylactic G-CSF (PPG). PATIENTS AND METHODS: This was a phase III study to compare FAC and TAC as adjuvant treatment of high-risk node-negative breast cancer patients. After the entry of the first 237 patients, the protocol was amended to include PPG in the TAC arm due to the high incidence of febrile neutropenia. A total of 1047 evaluable patients from 49 centres in Spain, two in Poland and four in Germany were included in the trial. Side-effects and the scores of the EORTC QLQ-C30 and QLQ BR-23 questionnaires were compared in the three groups (FAC, TAC pre-amendment and TAC post-amendment). RESULTS: The addition of PPG to TAC significantly reduced the incidence of neutropenic fever, grade 2-4 anaemia, asthenia, anorexia, nail disorders, stomatitis, myalgia and dysgeusia. Patient QoL decreased during chemotherapy, more with TAC than FAC, but returned to baseline values afterwards. The addition of PPG to TAC significantly reduced the percentage of patients with clinically relevant Global Health Status deterioration (10 or more points over baseline value) at the end of chemotherapy (64% versus 46%, P<0.03). CONCLUSIONS: The addition of PPG significantly reduces the incidence of neutropenic fever associated with TAC chemotherapy as well as that of some TAC-induced haematological and extrahaematological side-effects. The HRQoL of patients treated with TAC is worse than that of those treated with FAC but improves with the addition of PPG, particularly in the final part of chemotherapy treatment.

Adolescent↗
PubMed2001

Characterization of a recombinant monoclonal antibody by mass spectrometry combined with liquid chromatography.

In this report, we present the characterization of a humanized monoclonal antibody specific for the human epidermal growth factor receptor (hEGFR). Direct analysis by matrix assisted laser desorption ionization mass spectrometry (MALDI-MS) of peptide mixtures and chromatographically isolated fractions allowed identification of 94.0% and 85.4% of the amino acid sequence of light and heavy chains, respectively. Microheterogeneity sources were identified in light and heavy chains and a previously unreported posttranslational modification for immunoglobulins was found. One N-glycosylation site was identified in the heavy chain with non-sialylated bianntenary fucosylated structures. This study is one of the first to assess the potential of MALDI-MS in combination with more conventional protein chemistry techniques for the characterization of monoclonal antibodies.

Amino Acid Sequence↗
PubMed2001

[Variable response to the biological inhibition of platelets by abciximab in patients subjected to percutaneous coronary angioplasty].

INTRODUCTION AND OBJECTIVES: Abciximab has been shown to reduce the risk of thrombotic complications during coronary angioplasty, however there are still many aspects to be resolved. The aim of this study was to investigate the various biological effects of abciximab on platelets during coronary angioplasty. METHODS: The degree of platelet inhibition (with 5 and 20 mol/l concentrations of ADP), occlusion time (measurement of platelet haemostatic capacity, PFA-100), and the platelet activation markers were determined in 15 patients who underwent basal coronary angioplasty and abciximab treatment. Determinations were obtained before, 15 minutes after procedure initiation, at procedure termination, and 24 hours after procedure termination. RESULTS: More than 80% platelet aggregation inhibition was observed in 13 patients during the procedure, but after 24 hours (p < 0.05) was only detected in two. The occlusion time during the procedure was > 300 sec. in 13 patients, 6 of whom evolved to normal values after 24 hours (p < 0.05). A high correlation (p = 0.02) was found between these two parameters during the intervention, but not after 24 hours. No platelet inhibition or occlusion time changes were observed in 2 patients during the study. The expression of p-selectin increased significantly during the procedure (p < 0.05). CONCLUSIONS: The variability of platelet function inhibition and existence of circulating activation during coronary angioplasty following the administration of abciximab support the use of early analytical controls with the objective of modifying guidelines for use in order to optimize its effect or to combine it with other antithrombotic agents.

Abciximab↗
PubMed2000

[Aortic pseudocoarctation complicated by a giant pseudoaneurysm].

Pseudocoarctation of the aorta is an infrequent anomaly caused by the elongation and the congenital kinking of the aorta. We present a case of pseudocoarctation of the aorta with saccular aneurysm complicated with a large pseudoaneurysm. Both, magnetic resonance and aortography showed an aneurysm of the aortic isthmus that extended/progressed as pseudoaneurysm towards the neck. The patient was asymptomatic but due to the high risk of rupture, she underwent surgical reparation. The revision of the literature and our experience with this case show that pseudocoarctation of the aorta is not always a benign pathology and that surgical reparation should be performed in all those cases that are complicated by aneurysm.

Adult↗
PubMed1999

A randomized, open, parallel-group trial to compare the endocrine effects of oral anastrozole (Arimidex) with intramuscular formestane in postmenopausal women with advanced breast cancer.

BACKGROUND: This study provides a direct randomized comparison of a new-generation, non-steroidal aromatase inhibitor, anastrozole (Arimidex), with a steroidal aromatase inhibitor (formestane) with respect to oestrogen (oestradiol, oestrone, and oestrone sulphate) suppression and tolerability. PATIENTS AND METHODS: Sixty postmenopausal women with advanced breast cancer were randomized to receive either anastrozole 1 mg once daily orally (n = 29), or formestane 250 mg once every two weeks by intramuscular injection (n = 31). Treatment was continued until progression of disease or withdrawal from the study. The primary endpoints of this study were oestradiol suppression and tolerability. The secondary endpoints included oestrone and oestrone sulphate suppression. All laboratory analyses were conducted 'blind' of the randomized drug treatment. RESULTS: Anastrozole produced a greater and more consistent suppression of oestradiol levels compared with formestane. Based on two- and four-week measurements, the mean fall from baseline (pre-dose) in oestradiol level was 79% and 58% in the anastrozole and formestane groups, respectively (P = 0.0001). After four weeks of treatment, oestrone and oestrone sulphate levels were also suppressed to a greater extent by anastrozole compared with formestane (oestrone: 85% versus 67%, respectively, P = 0.0043; oestrone sulphate: 92% versus 67%, respectively, P = 0.0007). No statistical differences were seen between the two drugs in the incidence of adverse events. CONCLUSIONS: Anastrozole provides a more consistent and significantly more effective suppression of oestradiol compared with formestane. Similar results were observed for oestrone and oestrone sulphate. The clinical significance of these differences in total oestrogen suppression remains to be established.

Administration, Oral↗
PubMed1998

Analgesic, antiinflammatory, and antipyretic effects of S(+)-ketoprofen in vivo.

Many studies indicate that the S-enantiomers of arylpropionic (APA) nonsteroidal antiinflammatory drugs (NSAIDs) are the pharmacologically active enantiomers. S(+)-ketoprofen (dexketoprofen) stereoselectively inhibits cyclooxygenase (COX) in vitro but very little is known about the differential activity of ketoprofen enantiomers in vivo. We examined the analgesic, antiinflammatory, and antipyretic activities of S(+)-ketoprofen in rats and mice. First, we measured the antinociceptive action of S(+)-ketoprofen in abdominal pain models. After intravenous administration. 0.5 mg/kg S(+)-ketoprofen inhibited 92.1+/-2.2% of writhing in mice. Stereoselectivity in the activity was detected; intravenous administration of the R(-)-enantiomer resulted in no statistically significant activity in a dose range of 0.15-1 mg/kg. Similar results were obtained after oral administration in mice. In the rat, S(+)-ketoprofen was a more potent analgesic than diclofenac by both intravenous and oral administration. There was no significant difference between the analgesic effect of S(+)-ketoprofen treatment and the twofold dose of the racemic form in both the mouse and rat models. Second, we measured the antiinflammatory activity of S(+)-ketoprofen using a carrageenan-induced paw edema model in the rat. Intravenous administration of 5 mg/kg of S(+)-ketoprofen almost completely inhibited edema formation. After oral administration, S(+)-ketoprofen is both more potent and effective than diclofenac. Third, we measured antipyretic activity. S(+)-ketoprofen showed a marked antipyretic action (ED50 = 1.6 mg/kg) and was the most potent of the NSAIDs tested. S(+)-ketoprofen is a potent antiinflammatory, analgesic, and antipyretic agent in vivo, consistent with its potent anti-COX activity.

Administration, Oral↗
PubMed1997

The acrosome reaction response assay: a new way to identify patients in whom pentoxifylline would improve the human follicular fluid-induced acrosome reaction.

The effect of pentoxifylline on the spontaneous and follicular fluid (hFF)-induced acrosome reaction (AR) was studied in an attempt to identify those patients who would benefit from the use of pentoxifylline as an AR-stimulating agent. Pentoxifylline (1 mg/ml) produced no significant increase over spontaneous AR at any of the time points studied (60 min: 6.2% +/- 2.0 spontaneous AR vs 7.4% +/- 2.0 pentoxifylline AR; 120 min: 7.1% +/- 1.6 spontaneous vs 9.0% +/- 2.5 pentoxifylline; 180 min: 7.0% +/- 1.8 spontaneous vs 10.9% +/- 4.0 pentoxifylline, n = 6). On the other hand, hFF produced a significant increase in AR (6.9% spontaneous AR vs 11.2% hFF AR, p < 0.001, n = 39) and this effect was enhanced by pre-incubation with pentoxifylline (15.0% pentoxifylline + hFF AR vs 11.2% hFF AR, p < 0.001). There were no differences in percentage AR induced by hFF or pentoxifylline + hFF between patients with normal (n = 16) and abnormal (n = 25) semen samples. Individual analysis of the effects of hFF and pentoxifylline + hFF on AR showed great variability between patients and enabled us to classify them into four categories: inducible-responder (15%), non-inducible-responder (23%), inducible-non-responder (41%) and non-inducible-non-responder (21%). An induction index (II) (induction produced by hFF divided by spontaneous AR) and a response index (RI) (induction produced by pentoxifylline + hFF divided by hFF) were calculated for each sample. Patients previously classified as inducible exhibited an II > 0.30 and patients previously classified as responders showed an RI > 0.26. There was no correlation between II and RI values (Spearman, r = -0.185, p = 1). Our results show that pentoxifylline is an enhancer of the induced AR only in some patients. We propose an 'AR response assay' to identify responder patients and thus enable rational use of this drug.

Acrosome↗
PubMed1996

[Cardiac osteogenic sarcoma with chondroblastic differentiation].

Cardiac tumors are a rare disease. We show here one patient with a heart osteogenic sarcoma with chondroblastic differentiation. The clinical status was initiated with a cadre of cardiac tamponade. Transesophageal echocardiography and thoracic scanner were used to diagnose the cardiac tumor. The definitive diagnosis was confirmed with biopsy. At the present moment, there are very few cases reported in the references on osteogenic sarcoma with chondroblastic differentiation. The methods of diagnosis, the treatment and the histopathology are discussed.

Echocardiography, Transesophageal↗
PubMed1996

[Papillary muscle rupture during subaortic membrane balloon dilatation].

A 37 year-old female patient underwent catheter-balloon dilation for discrete subaortic stenosis. During the procedure severe mitral regurgitation was produced requiring emergency surgery. Transesophageal and intraoperative findings were posteriormedial papillary muscle rupture. Retrospective viewing of the cineangiogram during balloon inflation revealed distal balloon indentation, corresponding to the injured papillary muscle. This severe complication of the left ventricular outflow tract angioplasty should be avoided by careful positioning of the guidewire and balloon before inflation.

Adult↗
PubMed1995

Delayed papillary muscle rupture following mild chest trauma.

A case of delayed papillary muscle rupture is reported, which developed 24 hours following a mild chest trauma. Transthoracic echocardiography established the diagnosis; immediate mitral valve replacement was carried out. The postoperative course was uneventful.

Accidental Falls↗
PubMed1995

[The return to work after coronary revascularization].

INTRODUCTION: Work resumption after a therapeutical intervention has been considered as a sensitive indicator of its success. There are some reports analyzing working status after coronary artery revascularization in western countries. However, to our knowledge, similar studies have not been published in Spain. PATIENTS AND METHODS: We studied 210 patients after coronary artery revascularization surgery or percutaneous transluminal coronary angioplasty. Exclusion criteria were age of 65 or more years and female sex gender (n = 64). RESULTS: Working patient rate before and after coronary revascularization was respectively 63.2% and 28.9% for surgery, and 57.1% and 41.4% for percutaneous angioplasty (p = 0.11). None of the former inactive patients, with the exception of one in the surgery group, went back to work after the revascularization procedure. Asymptomatic patients after percutaneous angioplasty had a higher postprocedure working rate than symptomatic ones (58.1% vs 11.1%, p < 0.0001). Patients in the surgery group did not show this relation (30% vs 25%, p = 0.69). CONCLUSIONS: Surprisingly, coronary artery revascularization interventions, mainly coronary surgery, seems to behave in our environment as important determinants of working cessation.

Angioplasty, Balloon, Coronary↗
PubMed1994

Characterization and frequency distribution of sperm acrosome reaction among normal and infertile men.

We studied the acrosome reaction (AR) in human spermatozoa from 58 normal fertile men and 232 infertile patients. The median AR in the normal population was 17%; AR was > 9% in 83% of the subjects studied and only 2% of fertile individuals had a failed AR (< 5%). We calculated the within person variability using multiple specimens from each subject; the 95% confidence interval for each subject was 4 AR units above and 4 AR units below his mean value. In contrast, the median AR for the infertile population was 3%. AR values were below the normal range (< 5%) in 60% of the patients and only 26% of the patients had AR values > 9%. Because patients entered the study sequentially, without regard to the aetiology of infertility, the patient population comprised a wide variety of subjects ranging from individuals with good to extremely poor semen quality. There was a progressively greater number of individuals with a failed AR as semen quality deteriorated (P < 0.01). However, among patients with good count, motility and morphology, 20% unexpectedly had a failed AR, and among patients with severely impaired semen quality, 29% had a positive AR. We also analysed the relationship of AR values with other semen measurements. The frequency of acrosomal reactions was significantly correlated (Spearman, P < 0.001) with morphology (r = 0.509), concentration (r = 0.524), progression (r = 0.416) and percentage motility (r = 0.356), but not with the percentage of sperm moving at a curvilinear velocity of < or = 40 microns/s.(ABSTRACT TRUNCATED AT 250 WORDS)

Acrosome↗
PubMed1994

Acrosome reaction inducibility predicts fertilization success at in-vitro fertilization.

We prospectively studied the ability of acrosome reaction (AR) inducibility to predict fertilization success in a group of 232 infertile patients presenting sequentially for in-vitro fertilization (IVF). The median percentage of eggs fertilized for the overall patient population was 25% (interquartile range 5-58%), with one to 29 oocytes available for insemination (median, five oocytes). The median percentage of eggs fertilized at IVF increased as the percentage of spermatozoa able to undergo AR became greater: spermatozoa with a failed AR (< or = 5%) fertilized only 12% of eggs, while spermatozoa with AR values > 9% fertilized 50% of eggs. The assay had a specificity of 0.75, a sensitivity of 0.55 and an odds ratio of 2.9; thus, AR-positive patients are 2.9 times more likely to achieve fertilization than patients with a failed AR. Receiver operator characteristic (ROC) curves were constructed for AR, sperm concentration and percentage of normal forms in semen. All three parameters proved to be potentially useful in predicting the occurrence of fertilization, although AR and morphology appeared to be better than sperm concentration by ROC analysis. Patients were divided into four clearly defined subgroups according to their traditional semen characteristics, including morphology. The median percentage of eggs fertilized decreased as traditional semen characteristics deteriorated, from a median of 46% for patients with excellent sperm concentration, motility and morphology, to a median of 29% for patients with suboptimal semen quality and a median of 0% for patients with severely impaired semen.(ABSTRACT TRUNCATED AT 250 WORDS)

Acrosome↗
PubMed1993

Stereoselective cyclooxygenase inhibition in cellular models by the enantiomers of ketoprofen.

The pharmacological activity of rac-ketoprofen and its enantiomers was investigated in vitro using different cellular models. The effect of these compounds on arachidonic acid metabolism was assessed by measuring the inhibition of prostanoid generation under the action of several agonists. Thus, we have evaluated the inhibition of (1) thromboxane B2 synthesis in rabbit platelets and human polymorphonuclear leukocytes (PMNs), (2) prostaglandin E2 synthesis in three cultured cells, namely human umbilical vein endothelial cells (HUVEC), human keratinocytes, and mouse macrophage-like P388D1 cells. The IC50 values found for (+)-(S)-ketoprofen were in the range between 0.1 nM and 0.8 microM, being slightly lower in all models than those found for rac-ketoprofen (0.4 nM-3 microM). On the other hand (-)-(R)-ketoprofen showed inhibition of cyclooxygenase only at concentrations two or three orders of magnitude higher than those required for the (+)-(S) enantiomer. These results, obtained with cell types of relevance for inflammatory processes and with compounds of high optical purity, demonstrate that the prostanoid biosynthesis inhibition caused by the drug rac-ketoprofen is exclusively due to its dextrorotatory enantiomer.

Animals↗
PubMed1993

Chemical composition and protein source in the capacitation medium significantly affect the ability of human spermatozoa to undergo follicular fluid induced acrosome reaction.

We studied the effect of media composition on sperm capacitation, using Biggers-Whitten-Whittingham (BWW) medium, Ham's-F10 and a modified Tyrode's medium (HSM) supplemented with bovine serum albumin (BSA) or fetal cord serum (FCS). We evaluated the effect of chemical environment and protein supplementation on the sperm motion parameters of curvilinear velocity and linearity, and on the ability of incubated spermatozoa to undergo follicular fluid induced acrosome reaction. Neither chemical composition nor protein supplementation of capacitation media greatly affected motion parameters after 2 h incubation. Furthermore, chemical composition had only a small effect on the ability of spermatozoa to undergo the acrosome reaction upon exposure to follicular fluid. A higher proportion of spermatozoa underwent acrosome reaction after incubation in HSM (8% control (C); 28% follicular fluid) than in BWW (8% C, 17% follicular fluid) or Ham's F-10 (6% C, 19% follicular fluid). By contrast, protein source proved critical in determining acrosome reaction inducibility. Spermatozoa incubated in BSA-supplemented media showed a 4-fold increase in acrosomal discharge when exposed to follicular fluid (6% C, 22% follicular fluid) compared to controls while spermatozoa incubated in FCS were unable to undergo acrosome reaction (6% C, 6% follicular fluid). Simultaneous addition of FCS to BSA capacitation medium blocked acrosome reaction inducibility and the late addition of BSA, after sperm incubation in FCS, did not facilitate acrosome reaction. We propose that an inhibitor of sperm capacitation is present in FCS and therefore, the selection of optimum incubation conditions for spermatozoa may be of critical importance when evaluating or treating infertile patients.

Acrosome↗