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J López

Publications and source records attributed to J López.

At least 37 records · Page 2Linked to original sources
PubMed2001

Application of the sequential elution technique to determine Cd and Cu cellular location in Ulva lactuca Linnaeus.

The sequential elution technique, used to determine the cellular location of metals in nonvascular plants, was adapted to the seaweed Ulva lactuca Linnaeus for the heavy metals Cu and Cd. The optimum conditions for the extraction of extracellular Cu and Cd were determined using specimens previously loaded with these metals. The best extracellular metal extraction media and the number of extracellular metal extraction steps obtained were the following: Two steps (1 h + 40 min) in a filtered sea water-20 mM Ni solution for Cd and two steps in a filtered sea water-50 mM Co solution for Cu. To find these extraction conditions the extracellular metal extraction capacity of the different media used as well as the alteration provoked in plasmalemma permeability were compared. The concentrations of the incubation solutions of Cd and Cu that allowed reliable comparisons between the different extracellular metal extraction media used were previously determined.

Cadmium↗
PubMed2001

Biomonitoring of sporadic acidification of rivers on the basis of release of preloaded cadmium from the aquatic bryophyte Fontinalis antipyretica Hedw.

A technique is proposed for biomonitoring of sporadic acidification events in rivers. Individuals of the bioindicator species are pre-incubated with a chemical marker, then transplanted to the test location for the period of interest, then analysed for marker content; acidification events are inferred on the basis of the degree of reduction in marker concentration. To assess the validity of the proposed technique, we performed laboratory trials with the aquatic bryophyte Fontinalis antipyretica Hedw. as bioindicator species, and cadmium (Cd) as marker. The bryophytes were pre-incubated with a Cd solution, obtaining saturation concentrations in the extracellular compartment and near-saturation concentrations in the intracellular compartment. In a first series of experiments, Cd-preloaded bryophyte apices were maintained for 1-30 h in water of different pH; the results clearly indicated that the amount of Cd released is dependent on pH. In a second series of experiments, Cd-preloaded bryophyte apices were maintained for 1-24 h in water with various combinations of pH and aluminium (Al) concentration (Al being a highly toxic element that is typically mobilized in acid waters). In these experiments, pH again had a marked effect on the amount of Cd released, while Al concentration had no consistent effects. To facilitate data analysis, Davidson-type equations were fitted to the results of the second series of experiments, allowing prediction of medium acidity on the basis of Cd concentration remaining in the extracellular and intracellular compartments.

Acid-Base Imbalance↗
PubMed2001

[Effect of cAMP on the function of endothelial cells and fibromuscular proliferation after the injury of the carotid and coronary arteries in a porcine model].

INTRODUCTION AND OBJECTIVE: Reendothelization of damaged blood vessels protects against the vascular injury response. We evaluated in vivo whether a systemic increase in cAMP accelerates reendothelization and attenuates intimal hyperplasia in injured swine carotid and coronary arteries. METHODS: Both carotid arteries of 10 swines were subjected to balloon injury. Five animals had been treated with 2 ml (10 mg) of Forskolin, an activator of the adenylate cyclase, and another 5 with 2 ml of saline solution. These animals were sacrificed at day 8, and carotid artery reendothelization was evaluated. The descendent coronary (DC) artery of another 19 pigs was injured by atherotome. Nine animals had been treated with 2 ml of Forskolin, and another 10 with 2 ml of saline solution. These animals were sacrificed at day 28, with myointimal proliferation and arterial geometric remodelation being evaluated. Likewise, in these animals intracellular cAMP levels were measured at baseline and 28 and 60 minutes after saline solution or Forskolin administration and 90 min after arterial injury. RESULTS: Eight days after balloon injury, carotid artery reendothelization was greater in the Forskolin-treated group compared with the control group (p = 0.02), and the number of CD31 positive cells was statistically increased in the treated group (38 +/- 11 cells) versus controls (11 +/- 9 cells). Although the degree of vascular injury caused by atherotome was similar in all of the arteries in the control group, restenosis was only observed in 40% of these animals. Correlation analysis demonstrated that intracellular cAMP may condition arterial geometric remodeling and the diameter of the lumen after vascular injury. CONCLUSION: Our results suggest that cAMP may promote reendothelization and attenuate fibromuscular proliferation.

Animals↗
PubMed2001

Evolution of the need for operation for peptic pyloric stenosis over a period of 24 years (1976-1999).

OBJECTIVE: To analyse the need for operation for pyloric stenosis caused by duodenal ulcer over a period of 24 years (1976-1999). DESIGN: Retrospective study. SETTING: University hospital, Spain. SUBJECTS: 156 patients operated on for peptic pyloric stenosis. MAIN OUTCOME MEASURES: The number of patients operated on yearly were grouped into 4-year periods for statistical comparison. RESULTS: The number of cases operated on each year steadily decreased between 1976 and 1999. In the 1988-1991 period there was a significant reduction (p <0.05), which continued over the next two 4-year periods, particularly the last (p <0.01). CONCLUSION: Although we cannot use this study to establish a direct relation between the decrease in the indication for operations for peptic pyloric stenosis and the use of H2 antagonists, proton pump inhibitors, or treatment to eradicate Helicobacter pylori, we did find a significance difference between the years before and after the introduction of these drugs.

Adult↗
PubMed2001

Multiple bilateral fractures of the lumbar transverse processes in a roe deer (Capreolus capreolus).

Multiple bilateral fractures of the lumbar transverse processes were radiographically identified postmortem in a recently captured roe deer (Capreolus capreolus). These fractures were probably caused by an avulsion of the psoas major occurring during introduction into the transport box. The deer probably died from shock caused by the fractures, muscle damage, and subsequent hemorrhage. Although easily overlooked, fractured lumbar transverse processes may indicate inadequate postcapture management practices.

Animals↗
PubMed2001

Expression of the adrenomedullin binding protein, complement factor H, in the pancreas and its physiological impact on insulin secretion.

Adrenomedullin (AM) is a ubiquitous peptide hormone which, among other functional roles, reduces insulin secretion in the pancreas. Recently we have described the interaction between AM and the complement regulator protein factor H, which results in mutual modulation of their respective functions. Here we identify the expression of factor H in the beta cells of the rat pancreatic islets by immunohistochemistry and multiple immunofluorescence followed by confocal microscopy. In addition, double immunogold staining under the electron microscope showed coexistence of insulin and factor H immunoreactivities within the same secretory granules; interestingly, factor H staining was found in the electron-lucent haloes whereas the insulin antibody labeled preferentially the dense cores. The existence of factor H mRNA in the pancreas was confirmed by RT-PCR and in situ hybridization. The function of factor H in the pancreas was investigated with an insulin secretion assay. Addition of factor H to freshly isolated islets in the presence of AM resulted in a further reduction in insulin secretion with a concomitant elevation of cAMP, suggesting that factor H increases AM function in glucose homeostasis. The expression of factor H in the pancreas may play other important roles such as protection against complement-mediated cell lysis.

Adrenomedullin↗
PubMed2000

Is veno-occlusive disease a specific syndrome or the exacerbation of physiopathologic hemostatic changes in hematopoietic stem cell transplantation (HSCT)?

The objective of the present study was to analyze whether veno-occlusive disease (VOD) is based on specific findings or whether this syndrome is the exacerbation of changes in hemostatic parameters that develop following hematopoietic stem cell transplantation (HSCT). 40 patients undergoing HSCT were enrolled (6 allogeneic bone marrow transplantation and 34 peripheral stem cell rescue-2 allogeneic, 32 autologous). Measurements of hemostatic parameters (endothelial, hypercoagulability and fibrinolytic markers) were obtained prior to chemotherapy and weekly thereafter for 3 weeks. The incidence of VOD was 15%. HSCT showed a state of moderate hypercoagulability (increase of thrombin-antithrombin complex and fibrinogen, and decrease of Factor VII, Protein C, and antithrombin-III), probably as a consequence of marked endothelial damage (increase of von Willebrand Factor and tissue plasminogen activator). All these alterations create a potentially prothrombotic state, more pronounced in VOD. The decreasing incidence of VOD and the moderate disease in all patients suggest that increasing improvements in transplant strategies have reduced the risk and severity of a syndrome that at the beginning of the transplantation era was a leading cause of morbidity/mortality.

Adolescent↗
PubMed2000

The effect of pH on the kinetics of intra- and extracellular uptake of Al in Fontinalis antipyretica: changes in the cellular contents of K, Mg, and Ca.

The effect of acidity on the accumulation of Al in the aquatic bryophyte Fontinalis antipyretica was studied. The main interest of this study was in characterizing the relationship between the two parameters, as Al is typically mobilized in acidic environments, where it becomes extremely toxic. With this aim, a series of laboratory experiments were carried out where samples of F. antipyretica were held in tanks of water with different concentrations of Al (0.1-3 mg L(-1)) and levels of acidity (pH 3-5. 8). The incubation time varied between 1 and 24 h. In general, the greatest accumulations of both intra- and extracellular Al were found at a pH of 4.4. With the results obtained, the kinetics of both intra- and extracellular Al uptake was characterized, and models constructed for different combinations of Al and acidity. The study was completed by examining the relationship between the pH of the holding water and bioaccumulation of Al and the variation in concentration of cations essential to plant life, which are also indicators of changes in cellular physiology (K, Mg, Ca). In general, losses of these elements were found at intra- and extracellular locations, especially at high pH.

Aluminum↗
PubMed2000

The nervous system of the chicken proventriculus: an immunocytochemical and ultrastructural study.

The proventriculus constitutes the glandular region of the chicken stomach. This organ is innervated by two parasympathetic networks, the myenteric and submucous plexus, and here we present a systematic study of this system by immunohistochemistry and electron microscopy. All the neurons and fibres were positive for the neural markers, protein gene product 9.5 and the amidating enzymes. Immunoreactivities for the constitutive neuronal isoform of the enzyme nitric oxide synthase and the vasoactive intestinal peptide were present in neuronal bodies suggesting an intrinsic origin for the similarly immunoreactive fibres found in the proventriculus. On the other hand, immunoreactivity to gastric inhibitory peptide was only found in varicose fibres making contact with the blood vessels and the glandular epithelium, but never in the neuronal somas, suggesting that this substance may be provided by an extrinsic nervous system whose neuronal bodies are located elsewhere. Electron microscopy revealed frequent neuromuscular and neuroepithelial connections in the muscle layers, the wall of the blood vessels and the epithelium. In addition, synapsis-like structures were identified in the proximity of cells belonging to the diffuse endocrine system, providing a new example of neuroendocrine contacts. No positivity was found for antibodies against other neural substances including somatostatin, peptide histidine-isoleucine, peptide tyrosine-tyrosine, neuropeptide tyrosine, bombesin, met-enkephalin, serotonin, substance P, galanin, calcitonin gene-related peptide and S-100 protein.

Animals↗
PubMed2000

Colocalization of numerous immunoreactivities in endocrine cells of the chicken proventriculus at hatching.

The colocalization of regulatory peptide immunoreactivities in endocrine cells of the chicken proventriculus at hatching has been investigated using the avidin-biotin technique in serial sections and double immunofluorescence in the same section for light microscopy, and double immunogold staining for electron microscopy. In addition to the eight immunoreactivities previously described in this organ, cells immunoreactive for peptide histidine isoleucine (PHI), peptide gene product 9.5 (PGP), and the amidating enzyme, peptidylglycine alpha-amidating monooxygenase (PAM) were observed. All the cells immunoreactive to glucagon were also immunostained by the PHI antiserum. In addition, all the glucagon-like peptide 1, avian pancreatic polypeptide, and some of the neurotensin-like cells costored also glucagon- and PHI-immunoreactive substances. PGP- and PAM-immunoreactivities were also found in the glucagon-positive cells. A small proportion of the somatostatin-containing cells were positive for PHI but not for other regulatory peptides. These results could suggest either the existence of a very complex regulatory system or that the endocrine system of the newborn chickens is not yet fully developed.

Animals↗
PubMed2000

Tuberculosis after hematopoietic stem cell transplantation: incidence, clinical characteristics and outcome. Spanish Group on Infectious Complications in Hematopoietic Transplantation.

A national survey of tuberculosis after hematopoietic stem cell transplant (SCT) was undertaken to study incidence, clinical presentation and outcome. Twenty confirmed cases were found among 8,013 patients (eight in 5,147 autologous and 12 in 2,866 allogeneic SCT). The estimated incidence in cases/10(5) patients/year (95% CI) was 101 (56.5-145) for the whole group, 71.1 (21.8-120) in autologous and 135.6 (58.9-212) in allogeneic transplants. Compared with the general population, tuberculosis was more frequent after allogeneic (RR 2.95) but not after autologous SCT. Tuberculosis after SCT is a late infection (median 324 days post transplant), predominately affects the lungs (80% of the cases), appears to respond well to treatment but has a high mortality (25%) in allogeneic recipients. It can also complicate the post-transplant management as antituberculosis drugs frequently decrease the serum levels of cyclosporine causing an aggravation of GVHD. Graft-versus-host disease, corticosteroid treatment and total body irradiation appear to be associated with tuberculosis in allogeneic recipients. No obvious factors were associated with tuberculosis in autologous transplants. Finally, we found that the published literature on tuberculosis after solid and SCT has overestimated its incidence due to the direct translation of tuberculosis frequency into incidence.

Adult↗
PubMed2000

Oral oleoyl-estrone induces the rapid loss of body fat in Zucker lean rats fed a hyperlipidic diet.

OBJECTIVE: To test whether oleoyl-estrone affects body weight when given orally, which may help curtail the secondary growth-boosting effects of derived estrone. DESIGN: The rats were fed for 15 days with a powdered hyperlipidic diet (16.97 MJ/kg metabolizable energy) in which 46.6% was lipid-derived and 16.1% protein-derived energy (HL group), containing 1.23+/-0.39micromol/kg of fatty-acyl esters of estrone. This diet was supplemented with additional oleoyl-estrone to produce diets with 2.5 micromol/kg (diet OE2.5), 4.4 micromol/kg (diet OE4.4), and 33.3 micromol/kg content in fatty-acyl estrone (diet OE33). SUBJECTS: Twelve-week old female Zucker lean (Fa/?) rats initially weighing 200-235g. MEASUREMENTS: Food intake and body weight changes; urine and droppings production and nitrogen content. Body composition (water, lipid, protein) and total energy. Energy and nitrogen balances. Plasma chemistry including free amino acids. RESULTS: Oral administration of oleoyl-estrone in a hyperlipidic diet resulted in significant losses of fat, energy and, ultimately, weight, which were dependent on the dose of oleoyl-estrone ingested. Treatment induced the maintenance of energy expenditure combined with lower food intake, creating an energy gap that was filled with internal fat stores whilst preserving body protein. The decrease in food intake was not a consequence of food aversion but of diminished appetite. Energy expenditure was practically constant for all groups except for the OE33, which showed values about 25% lower than the controls. In most of the groups studied, there was a net protein deposition in spite of severe lipid and energy drainage. Amino acid levels agreed with this N-sparing shift. In spite of lowered energy intake, the N balance was positive or near zero in all groups, with a sizeable N-gap in controls and in lower-dose groups that disappeared in the OE33 group. CONCLUSION: Treatment of rats with a hyperlipidic diet containing added oleoyl-estrone resulted in the dose-related loss of fat reserves with scant modification of other metabolic parameters and preservation of body protein. The results agree with the postulated role of oleoyl-estrone as a ponderostat signal and open the way for its development as anti-obesity drug.

Adipose Tissue↗
PubMed2000

Autologous peripheral blood progenitor cell transplantation with <2 x 10(6) CD34(+)/kg: an analysis of variables concerning mobilisation and engraftment.

INTRODUCTION: This study analyses the factors affecting mobilisation and engraftment in autologous peripheral blood progenitor cell transplantation according to the number of CD34(+) re-infused. MATERIALS AND METHODS: A total of 190 patients underwent mobilisation with G-CSF alone (n=113) or in combination with chemotherapy (n=77). A total of 116 patients (61%) were autografted with <2 x 10(6) CD34(+) cells/kg and 74 patients were transplanted with >2 x 10(6) CD34(+) cells/kg. Rates of granulocyte and platelet recovery were estimated using the product-limit method of Kaplan-Meier and compared using a log-rank test. The Cox regression model was used for the multivariate analysis of factors influencing engraftment. Differences between cohorts were evaluated by one-way ANOVA or Mann-Whitney tests, and multivariate analysis was performed using a stepwise lineal regression. RESULTS: Neutrophil and platelet engraftment was significantly longer with <2 x 10(6)/CD34(+)/kg (12 vs 10 days, P=0.014 and 16 vs 13 days, P=0.0001 respectively). Platelet recovery was affected by exposure to alkylating agents (P=0.04), refractory disease (P=0.02) and AML (P=0.0001), but only the last two variables remained significant in Cox regression (P<0.01). Granulocyte engraftment was longer in CML (univariate, P=0.04) and in refractory disease (multivariate, P=0.02). In patients re-infused with >2 x 10(6)/CD34(+)/kg, the Cox model did not identify prognostic factors for haematopoietic recovery. CONCLUSION: Although mobilisation schedules and disease status influenced not only the yield of progenitor cells, but also the engraftment kinetics, the number of CD34(+) re-infused was the main predictor of haematopoietic recovery. While engraftment succeeded in most of the cases, the re-infusion of >2 x 10(6)/CD34(+)/kg resulted in significantly shorter recovery times.

Adolescent↗
PubMed2000

Detection of specific IgM antibody in the investigation of an outbreak of pneumonia due to Legionella pneumophila serogroup 1.

OBJECTIVE: Management of outbreaks of pneumonia due to Legionella pneumophila serogroup 1 (SG1) infection requires rapid and accurate diagnostic tests. Current serologic approaches, based on detection of seroconversion for total antibody, do not fulfil this requirement. METHODS: A diagnostic test based on detection of IgM antibody to L. pneumophila SG1 by indirect immunofluorescence was developed and used to evaluate serum samples from patients involved in a community outbreak of L. pneumophila SG1 pneumonia that occurred in Spain. RESULTS: Testing of samples from serologically proven, sporadic cases of pneumonia due to L. pneumophila SG1 (14), cases of atypical pneumonia due to other infectious agents (16) and healthy controls (100) supported the sensitivity and specificity of the assay. On samples from the outbreak, the IgM assay recognized five of six cases with isolation of L. pneumophila SG1 from respiratory secretions or lung tissue and more than 70% of cases with confirmed or presumptive diagnosis as determined by the current serologic criteria. In addition, the IgM assay was positive in 23-70% of patients who fulfilled the clinical and epidemiologic criteria of case definition but did not display diagnostically significant serologic results or who lacked a detectable antibody response in the routine assay. Among cases confirmed by the current criteria, detection of specific IgM was occasionally achieved before the conventional serology gave significant results. CONCLUSION: Incorporation of IgM antibody detection in the current diagnostic criteria for L. pneumophila SG1 infection may help to improve the management of outbreaks of pneumonia due to this agent.

Antibodies, Bacterial↗
PubMed2000

Oral health management implications in patients with tuberous sclerosis.

We report 6 cases of patients with tuberous sclerosis and concomitant dental pathosis. The multiple manifestations in tuberous sclerosis determine its impact on dental therapy. A lack of awareness of this condition may compound the possible side effects of dental treatment. Possible preventive measures by dentists are highlighted in this presentation. Medical evaluation and the control of risk factors in relation to general anesthesia and sedation are key considerations for the management of patients with tuberous sclerosis.

Adolescent↗
PubMed2000

The role of imaging techniques in the study of renal osteodystrophy.

Secondary hyperparathyroidism is the most common form of this condition found in renal osteodystrophy. Enlarged parathyroid glands are the rule in severe secondary hyperparathyroidism because of a marked parathyroid cell hyperplasia. For several years, ultrasonography, computed tomography, and scintigraphy with thallium201-technetium99 have been useful techniques to identify enlarged parathyroid glands. More recently, ultrasonography with color Doppler and parathyroid scintigraphy with 99mTc-sestamibi have proved to be useful as well. Computed tomography and magnetic resonance imaging can be used, but their sensitivity is similar to ultrasonography and they cost more. Ultrasonography with color Doppler signals has made it possible to evaluate tissue blood supply, an aid in differentiating thyroid nodules. The degree of blood supply may be an indirect index of cell proliferation when there is neither necrosis nor calcification, because an enriched blood supply suggests vigorous cell growth and nodule formation. Scintigraphy with 99mTc-sestamibi allows identification of ectopic glands, including those located in the mediastinum, and also provides functional information. Sestamibi uptake is closely related to both parathyroid hormone levels and to the histological type of parathyroid proliferation. In our experience, when hyperparathyroidism is not too severe, 2 weeks after 2 g of calcitriol is administered intravenously, these scintigraphic images can disappear (inhibition test). This suggests a possibility for a medical treatment. By contrast, when parathyroid hormone levels are higher, parathyroid sestamibi uptake remained unchanged. In such patients, parathyroidectomy or ethanol injection should be the best treatment. These glands would correspond to the most actively functioning glands; they would have a lesser expression of vitamin D receptors, rendering them refractory to medical treatment with calcitriol.

Chronic Kidney Disease-Mineral and Bone Disorder↗
PubMed2000

Predictive value of nuclear factor kappaB activity and plasma cytokine levels in patients with sepsis.

The relationship between fluctuating cytokine concentrations in plasma and the outcome of sepsis is complex. We postulated that early measurement of the activation of nuclear factor kappaB (NF-kappaB), a transcriptional regulatory protein involved in proinflammatory cytokine expression, may help to predict the outcome of sepsis. We determined NF-kappaB activation in peripheral blood mononuclear cells of 34 patients with severe sepsis (23 survivors and 11 nonsurvivors) and serial concentrations of inflammatory cytokines (interleukin-6, interleukin-1, and tumor necrosis factor) and various endogenous antagonists in plasma. NF-kappaB activity was significantly higher in nonsurvivors and correlated strongly with the severity of illness (APACHE II score), although neither was related to the cytokine levels. Apart from NF-kappaB activity, the interleukin-1 receptor antagonist was the only cytokine tested whose level in plasma was of value in predicting mortality by logistic regression analysis. These results underscore the prognostic value of early measurement of NF-kappaB activity in patients with severe sepsis.

Adult↗