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Biomedical subjects

A Ortega

Publications and source records attributed to A Ortega.

At least 19 recordsLinked to original sources
PubMed2006

Identification of a calcium-dependent matrix metalloproteinase complex in rat chorioallantoid membranes during labour.

The induction of the expression of matrix metalloproteinases (MMPs) and their extracellular activation are key processes in connective tissue degradation in the chorioallantoid membrane during rat labour. However, the regulatory mechanisms remain largely unknown. Here, we report the identification of a calcium-dependent high molecular weight complex composed of MMP-9, MMP-3, MMP-2, tissue inhibitor of metalloproteinase 1 (TIMP-1) and TIMP-2, identified by zymography and western blotting. Molecular sieve chromatography confirmed the presence of a complex of MMPs and TIMPs with an exclusion volume >670 kDa. Differential scanning calorimetry of the complex confirmed the existence of a macromolecular complex that unfolds with a broad transition; it is denatured over a wide range of temperatures and has a T(m) of 72 degrees C in the presence of Ca(2+). When denatured in the absence of Ca(2+), there were at least eight transitions with T(m)s that corresponded to pro-MMP-9, MMP-9, pro-MMP-3, MMP-3, pro-MMP-2, MMP-2, TIMP-1 and TIMP-2. Co-localization of the same molecular components was demonstrated by confocal microscopy using cell-depleted chorioallantoid membranes. The assembly and disassembly of the complex can be reproduced at physiological concentrations of Ca(2+). This complex provides a potential mechanism for the enzymatic regulation of MMPs, which may participate in connective tissue degradation leading to the rupture of the fetal membranes during labour.

Animals↗
PubMed2006

Glutamate-dependent translational regulation in cultured Bergmann glia cells: involvement of p70S6K.

Glutamate, the main excitatory amino acid transmitter in the vertebrate brain is involved in the dynamic changes in protein repertoire that underlie synaptic plasticity. Activity-dependent differential expression patterns occur not only in neurons but also in glial cells. In fact, a membrane to nuclei signaling has been described after ionotropic glutamate receptor stimulation in cultured chick cerebellar Bergmann glia cells. In order to characterize other levels of protein expression regulation, we explored the effect of glutamate treatment in [35S]-methionine incorporation into newly synthesized polypeptides. A time-dependent modification in protein synthesis was found. An important component of translational control is the ribosomal S6 protein kinase. Threonine phosphorylation renders the kinase active increasing translation initiation. Glutamate exposure results in ribosomal S6 protein kinase Thr389 phosphorylation in a dose and time-dependent manner that matches perfectly with the overall protein synthesis profile detected upon the excitatory amino acid. Pharmacological characterization of the receptors involved suggests the participation of both ionotropic as well as metabotropic glutamate receptors. The non-receptor tyrosine kinase Src, phosphatidylinositol 3-kinase, protein kinase B and the mammalian target of rapamycin are mediators of the glutamate effect. These results not only demonstrate that glutamate receptors activation is critically involved in translational control in glial cells adjacent to synaptic processes like cerebellar Bergmann glia cells, but also further strengthen the notion of an active participation of glial cells in synaptic transmission.

Analysis of Variance↗
PubMed2006

Benzene metabolites induce apoptosis in lymphocytes.

Benzene is an important environmental pollutant with important health implications. Exposure to this aromatic hydrocarbon is associated with hematotoxicity, and bone marrow carcinogenic effects. It has been shown that benzene induces oxidative stress, cell cycle alterations, and programmed cell death in cultured cells. Hepatic metabolism of benzene is thought to be a prerequisite for its bone marrow toxicity. Nevertheless, there are no reports on the cellular effects of reactive intermediates derived from hepatic metabolism of benzene. Thus, the goal of this project was to determine the cellular alterations of benzene metabolites produced by the cultured hepatic cell line HepG2. Supernatants collected from these cells were applied to a culture of freshly isolated lymphocytes. A higher decrease in cell viability was found in cells exposed to these supernatants than to unmetabolized benzene. This viability decrease was due to apoptosis, as determined by Terminal deoxynucleotidyl Transferase Biotin-dUTP Nick End Labeling (TUNEL) assay and internucleosomal fragmentation of DNA. When supernatants were analyzed by HPLC, we found that not all the hydrocarbon was biotransformed, since a 28 microM concentration (37%) remained. The only metabolite found in the culture medium was muconic acid. The present results show that muconic acid derived from benzene metabolism is able to cooperate with the pollutant for the induction of apoptosis in rat lymphocytes.

Animals↗
PubMed2006

The parathyroid hormone-related protein system and diabetic nephropathy outcome in streptozotocin-induced diabetes.

The pathophysiology of the diabetic kidney (e.g., hypertrophy, increase urinary albumin excretion (UAE) is still ill-defined. Parathyroid hormone-related protein (PTHrP) is overexpressed in several nephropathies, but its role remains unclear. We evaluated the effect of high glucose on PTHrP and the PTH1 receptor (PTH1R) protein (by Western blot and immunohistochemistry) in the kidney of mice ith streptozotocin-induced diabetes, and in several mouse renal cells in vitro. Diabetic mice showed a significantly increased renal expression of PTHrP and PTH1R proteins with 2-8 weeks from the onset of diabetes. These animals exhibited an intense immunostaining for both proteins in the renal tubules and glomeruli. Using transgenic mice overexpressing PTHrP targeted to the renal proximal tubule, we found a significant increase in the renal hypertrophy index and in UAE in these diabetic mice relative to their control littermates. Moreover, logistic regression analysis showed a significant association between both PTHrP and PTH1R protein levels and UAE in all diabetic mice throughout the study. High-glucose (25 mm) medium was found to increase PTHrP and PTH1R in tubuloepithelial cells, mesangial cells and podocytes in vitro. Moreover, this increase in PTHrP (but not that of PTH1R) was inhibited by the AT1 receptor antagonist losartan. Collectively, these results indicate that the renal PTHrP/PTH1R system is upregulated in streptozotozin-induced diabetes in mice, and appears to adversely affect the outcome of diabetic renal disease. Our findings also suggest that angiotensin II might have a role in the PTHrP upregulation in this condition.

Angiotensin II↗
PubMed2006

Multidrug-resistant tuberculosis without HIV infection: success with individualised therapy.

OBJECTIVE: To evaluate the results of the treatment of non-HIV-infected multidrug-resistant tuberculosis (MDR-TB) patients admitted to a tuberculosis unit in a reference centre between June 1998 and December 2000. RESULTS: Twenty-five patients were studied (23 men). Empirical treatment was selected according to drugs previously used and adjusted according to in vitro test results. Patients had previously received an average of 5.5 drugs and were resistant to an average of 4.7 drugs. They were treated with a median number of four drugs (an injectable drug plus three oral drugs) for a median of 18 months. Ofloxacin and cycloserine was used in 17 cases (68%), ethionamide/prothionamide in 18 (72%) and para-aminosalicylic acid in 12 patients (48%). Psychological support and counselling was provided. Two patients required surgery. Globally, 21 patients (84%) met cure criteria. After a 24-month follow-up, none of the 21 patients who successfully completed treatment presented relapse or death. CONCLUSION: MDR-TB is a curable disease in non-HIV-infected patients. Individualised treatment regimens should be based on treatment history and the study of in vitro susceptibility and by promoting a relationship with the patient that makes adherence to treatment easier and minimises side effects.

Adult↗
PubMed2006

[Plan for stroke healthcare delivery].

INTRODUCTION: All stroke patients should receive the same degree of specialized healthcare attention according to the stage of their disease, independently of where they live, their age, gender or ethnicity. OBJECTIVE: To create an organized healthcare system able to offer the needed care for each patient, optimizing the use of the existing resource. METHODS: A committee of 14 neurologists specialized in neurovascular diseases representing different regions of Spain evaluated the available scientific evidence according to the published literature. RESULTS: During the acute phase, all stroke patients must be evaluated in hospitals that offer access to specialized physicians (neurologists) and the indicated diagnostic and therapeutic procedures. Hospitals that deliver care to acute stroke patients must be prepared to attend these patients and need to arrange a predefined transferring circuit coordinated with the extrahospitalary emergency service. Since resources are limited, they should be structured into different care levels according to the target population. Thus, three types of hospitals will be defined for stroke care: reference stroke hospital, hospital with stroke unit, hospital with stroke team.

Delivery of Health Care↗
PubMed2005

MULTIHYDRO and MONTEHYDRO: conformational search and Monte Carlo calculation of solution properties of rigid or flexible bead models.

A computer program, MULTIHYDRO, has been constructed for the calculation of hydrodynamic coefficients and other solution properties of multiple possible conformations of a bead model. With minimal additional programming to describe the model under study, this program interfaces efficiently with HYDRO for the calculation of solution properties, including hydrodynamic coefficients, radius of gyration, covolume, etc. A useful application is the conformation search of rigid macromolecules, because many possible conformations can be evaluated in a single run of the program. In this paper we also pay attention to the properties of flexible macromolecules, in the so-called Monte Carlo rigid-body approximation, which is virtually exact for the simpler solution properties. The theoretical aspects of the procedure are described, and we show how MULTIHYDRO can be employed for this calculation. However, for flexible molecules, a more general simulation scheme is importance-sampling Monte Carlo generation. We describe how this procedure is implemented in another computer program, MONTEHYDRO. Examples of the usage of these tools are provided.

Macromolecular Substances↗
PubMed2005

Localization of the Drosophila protein FL(2)D in somatic cells and female gonads.

The Drosophila gene female-lethal(2)d [fl(2)d] has been implicated in the alternative splicing regulation of genes involved in sexual determination, such as Sex-lethal and transformer, and in the alternative splicing of the gene Ultrabithorax. Here, the expression and subcellular localization of the FL(2)D protein is reported. FL(2)D is ubiquitously expressed in embryos, in imaginal discs of larvae and in ovaries. In Schneider cells, the protein is detected throughout the nucleoplasm, excluding the nucleolus, and partially co-localizes with SXL in nuclear speckles. In addition, FL(2)D associates with multiple transcriptionally active loci on salivary gland polytene chromosomes, consistent with the proposal that the protein is involved in the post-transcriptional regulation of a variety of genes. Interestingly, the localization of FL(2)D in nurse cells changes during oogenesis, from a rather diffuse early nuclear pattern in the germarium to a preferential accumulation at the nuclear periphery of nurse cells of developing cysts.

Animals↗
PubMed2005

ESR dating at Mezmaiskaya Cave, Russia.

Mezmaiskaya Cave has yielded more than 10,000 artifacts, thousands of very well preserved faunal remains, and hominin remains, found in seven Middle Paleolithic (Mousterian) and three Upper Paleolithic levels. A complete Neanderthal infant skeleton was preserved in anatomical juxtaposition lying on a large limestone block, overlain by the earliest Mousterian layer, Layer 3. Twenty-four skull fragments from a 1-2 year-old Neanderthal infant, showing post-mortem deformation, occurred in a pit originating in the Mousterian Layer 2 and penetrating into underlying layers 2A and 2B(1). Bone from Layer 2A was dated by AMS 14C at 35.8-36.3+/-0.5 kyr BP. Direct dating of Neanderthal bone from Layer 3 gave an age of 29 kyr, but that is now considered to be due to contamination by modern carbon. Fourteen large mammal teeth from Layers 2 through 3 have been dated by standard electron spin resonance (ESR). Low U concentrations in both the enamel and dentine ensure that ESR ages do not depend significantly on the U uptake model, but do depend strongly on the sedimentary dose rates. Assuming a sedimentary water concentration equal to 20 wt%, ESR ages for the Mousterian layers range from 36.2 to 73.0+/-5.0 ka.

Age Determination by Skeleton↗
PubMed2005

Systematic molecular characterization of multidrug-resistant Mycobacterium tuberculosis complex isolates from Spain.

We used spoligotyping and restriction fragment length polymorphism (RFLP) of the IS6110-insertion sequence to study the molecular epidemiology of multidrug-resistant (MDR) tuberculosis in Spain. We analyzed 180 Mycobacterium tuberculosis complex isolates collected between January 1998 and December 2000. Consecutive isolates from the same patients (n = 23) always had identical genotypes, meaning that no cases of reinfection occurred. A total of 105 isolates (58.3%) had unique RFLP patterns, whereas 75 isolates (41.7%) were in 20 different RFLP clusters. Characterization of the katG and rpoB genes showed that 14 strains included in the RFLP clusters did not actually cluster. Only 33.8% of the strains isolated were suggestive of MDR transmission, a frequency lower than that for susceptible strains in Spain (46.6%). We found that the Beijing/W genotype, which is prevalent worldwide, was significantly associated with immigrants. The 22 isolates in the largest cluster corresponded to the Mycobacterium bovis strain responsible for two nosocomial MDR outbreaks in Spain.

Adult↗
PubMed2003

Calculation of the solution properties of flexible macromolecules: methods and applications.

While the prediction of hydrodynamic properties of rigid particles is nowadays feasible using simple and efficient computer programs, the calculation of such properties and, in general, the dynamic behavior of flexible macromolecules has not reached a similar situation. Although the theories are available, usually the computational work is done using solutions specific for each problem. We intend to develop computer programs that would greatly facilitate the task of predicting solution behavior of flexible macromolecules. In this paper, we first present an overview of the two approaches that are most practical: the Monte Carlo rigid-body treatment, and the Brownian dynamics simulation technique. The Monte Carlo procedure is based on the calculation of properties for instantaneous conformations of the macromolecule that are regarded as if they were instantaneously rigid. We describe how a Monte Carlo program can be interfaced to the programs in the HYDRO suite for rigid particles, and provide an example of such calculation, for a hypothetical particle: a protein with two domains connected by a flexible linker. We also describe briefly the essentials of Brownian dynamics, and propose a general mechanical model that includes several kinds of intramolecular interactions, such as bending, internal rotation, excluded volume effects, etc. We provide an example of the application of this methodology to the dynamics of a semiflexible, wormlike DNA.

Centrifugation, Density Gradient↗
PubMed2003

[Reliability of Venturi oxygen therapy systems].

Venturi systems are among the most widely used devices for delivering oxygen therapy. Nevertheless, rigorous quality control of their reliability is lacking. In this study we used mass spectrometry to evaluate Venturi systems sold by various companies in Spain. We also studied tolerance under various conditions (changes in oxygen flow and with increased system resistance). Fixed systems were found to comply well with recommendations, whereas none of the variable systems complied. One system (Oxigem Variable) was unable to provide an oxygen concentration below 31% when set to deliver at 24% to 28%. We conclude that the variable masks available in Spain do not comply with European Union recommendations and the range of error of one of them (Oxigem Variable) means it is not clinically useful. Fixed systems were the most reliable ones in our market, and airlife and intersurgical devices were the variable systems that best approximated the reliability of fixed systems.

Equipment Safety↗
PubMed2003

RAPD method useful for distinguishing Leishmania species: design of specific primers for L. braziliensis.

The technique of Random Amplification Polymorphic DNA allows fragments of the genome to be amplified by means of polymerase chain reaction (PCR) without previous knowledge of their sequences. The protozoa of the genus Leishmania present great genetic variability, making it difficult to characterize the different species. A method is developed with a single 10-mers long primer, which allows the species L. braziliensis, L. mexicana, L. infantum, L. tropica, L. chagasi, L. amazonensis and L. major to be differentiated. These products amplified by RAPD have also facilitated the design of some primers that amplify L. braziliensis DNA exclusively.

Animals↗
PubMed2003

Development of a rapid polymerase chain reaction-ELISA assay using polystyrene beads for the detection of Toxoplasma gondii DNA.

AIMS: To develop a rapid colourimetric assay for the detection of Toxoplasma gondii DNA using polystyrene beads as solid support. METHODS AND RESULTS: A nested-polymerase chain reaction (PCR)-ELISA assay for the detection of T. gondii DNA was standardized by optimizing the hybridization time and probe concentration. Its detection threshold was then determined and compared with Southern blotting hybridization. These were found to be equivalent, but the PCR-ELISA-beads test is easier to perform and the turnaround time is much shorter than with Southern blot. CONCLUSIONS: The PCR-ELISA-beads assay is a valuable tool for the detection of T. gondii DNA. SIGNIFICANCE AND THE IMPACT OF THE STUDY: Our results demonstrate that this PCR-ELISA assay, using polystyrene beads, can be used as a routine diagnostic test for the detection of T. gondii in clinical laboratories.

Animals↗
PubMed2003

Cost-effectiveness of three combinations of antiemetics in the prevention of postoperative nausea and vomiting.

BACKGROUND: This study compares the cost-effectiveness of three combinations of antiemetics in the prevention of postoperative nausea and vomiting (PONV). METHODS: We conducted a prospective, double-blind study. Ninety ASA I-II females, 18-65 yr, undergoing general anaesthesia for major gynaecological surgery, with standardized postoperative analgesia (intrathecal 0.2 mg plus i.v. PCA morphine), were randomly assigned to receive: ondansetron 4 mg plus droperidol 1.25 mg after induction and droperidol 1.25 mg 12 h later (Group 1); dexamethasone 8 mg plus droperidol 1.25 mg after induction and droperidol 1.25 mg 12 h later (Group 2); ondansetron 4 mg plus dexamethasone 8 mg after induction and placebo 12 h later (Group 3). A decision analysis tree was used to divide each group into nine mutually exclusive subgroups, depending on the incidence of PONV, need for rescue therapy, side effects and their treatment. Direct cost and probabilities were calculated for each subgroup, then a cost-effectiveness analysis was conducted from the hospital point of view. RESULTS: Groups 1 and 3 were more effective (80 and 70%) than Group 2 (40%, P=0.004) in preventing PONV but also more expensive. Compared with Group 2, the incremental cost per extra patient without PONV was euro;6.99 (95% CI, -1.26 to 36.57) for Group 1 and euro;13.55 (95% CI, 0.89-132.90) for Group 3. CONCLUSION: Ondansetron+droperidol is cheaper and at least as effective as ondansetron+ dexamethasone, and it is more effective than dexamethasone+droperidol with a reasonable extra cost.

Adolescent↗
PubMed2003

Lymphocytic hypophysitis successfully treated with azathioprine: first case report.

An aggressive case of lymphocytic hypophysitis is described which was successfully treated with azathioprine after failure of corticosteroids. The patient, aged 53, had frontal headache, diplopia, and diabetes insipidus. Cranial magnetic resonance imaging (MRI) showed an intrasellar and suprasellar contrast enhancing mass with involvement of the left cavernous sinus and an enlarged pituitary stalk. A putative diagnosis of lymphocytic hypophysitis was made and prednisone was prescribed. Symptoms improved but recurred after the dose was reduced. Trans-sphenoidal surgery was attempted but the suprasellar portion of the mass could not be pulled through the pituitary fossa. Histological examination confirmed the diagnosis of lymphocytic hypophysitis. Two months later he developed aseptic meningoencephalitis which was treated with high dose methylprednisolone pulse therapy. MRI revealed a progression of suprasellar mass. At this stage azathioprine treatment was begun. Four weeks later MRI shown no evidence of residual lesion and no pituitary stalk enlargement. After follow up of 18 months without azathioprine there was no clinical or radiological evidence of the disease. This is the first evidence of the efficacy of azathioprine treatment in a patient with lymphocytic hypophysitis.

Adrenal Cortex Hormones↗
PubMed2003

Cerebral hypoperfusion detected by SPECT in patients with systemic lupus erythematosus is related to clinical activity and cumulative tissue damage.

Cerebral single-photon emission computed tomography (SPECT) is a sensitive technique for the detection of central nervous system (CNS) involvement in systemic lupus erythematosus (SLE). The objective was to determine whether a relationship exists between cerebral hypoperfusion as detected by cerebral SPECT, cumulative tissue damage and the clinical activity of SLE. Cerebral technetium-99m-L,L-ethyl cysteinate dimer (99mTc-ECD) SPECT was performed in two groups of patients: 10 women with SLE (Group A) who had no previous history of major neuropsychiatric (NPS) manifestations and no minor NPS symptoms in the last six months, and 57 unselected women with SLE (Group B). In the same week that SPECT was performed, the SLE disease activity index (SLEDAI), SLICC/ACR damage index, native anti-DNA antibodies (ELISA) and erythrocyte sedimentation rate (ESR) were determined. In Group A, cerebral SPECT showed moderate or severe hypoperfusion (abnormal SPECT) in five patients without NPS symptoms, unrelated to age (mean 24.8 versus 27.8 years) or disease duration (mean 6.8 versus 9 years). Patients with significant cerebral hypoperfusion had greater clinical disease activity (mean SLEDAI 13.6 versus 7.6) (SLEDAI > 7 in 5/5 versus 1/5; Fisher: 0.023; OR: 33; 95% CI: 2.3-469.8) and ESR (mean 43.6 versus 9.8; P < 0.05). In Group B, the mean age of the 57 unselected women with SLE was 37 years (SD 6.3) and the mean duration of the disease was 9.7 years (SD 6.3). Cerebral SPECT revealed normal perfusion or mild hypoperfusion (normal SPECT) in 30 patients (52.6%), and moderate or severe hypoperfusion in 27 (47.4%). Hypoperfusion was unrelated to age, duration of SLE or concentrations of anti-DNA antibodies and C3 and C4 fractions. Patients with significant cerebral hypoperfusion had more active clinical disease (mean SLEDAI 13.92; SD 8.44 versus 4.56; SD 4.15) (Mann-Whitney, P < 0.005), more cumulative tissue damage (mean SLICC 2.66; SD 2.84 versus 1.03; SD 1.51) (Mann-Whitney, P = 0.035), and higher ESR values (mean 28.7; SD 22.5 versus 17.7; SD 13.3) (Mann-Whitney, P = 0.023) than patients with normal SPECT studies. Significant cerebral hypoperfusion was related both to NPS manifestations present at the time of the study (17 of 27, 63% versus 3 of 30, 10%) (OR: 15.3) and cumulative manifestations (19 of 27, 70.4% versus 8 of 30, 26.7%) (OR: 6.5), whether mild (OR: 5.5) or severe (OR: 8.2). In conclusion, cerebral hypoperfusion detected by SPECT in patients with SLE is related to clinical activity (SLEDAI), cumulative tissue damage (SLICC) and concomitant or previous NPS manifestations.

Adolescent↗