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Biomedical subjects

J Escudero

Publications and source records attributed to J Escudero.

At least 19 recordsLinked to original sources
PubMed2006

Analysis of electroencephalograms in Alzheimer's disease patients with multiscale entropy.

The aim of this study was to analyse the electroencephalogram (EEG) background activity of Alzheimer's disease (AD) patients using multiscale entropy (MSE). MSE is a recently developed method that quantifies the regularity of a signal on different time scales. These time scales are inspected by means of several coarse-grained sequences formed from the analysed signals. We recorded the EEGs from 19 scalp electrodes in 11 AD patients and 11 age-matched controls and estimated the MSE profile for each epoch of the EEG recordings. The shape of the MSE profiles reveals the EEG complexity, and it suggests that the EEG contains information in deeper scales than the smallest one. Moreover, the results showed that the EEG background activity is less complex in AD patients than control subjects. We found significant differences between both subject groups at electrodes F3, F7, Fp1, Fp2, T5, T6, P3, P4, O1 and O2 (p-value < 0.01, Student's t-test). These findings indicate that the EEG complexity analysis performed on deeper time scales by MSE may be a useful tool in order to increase our knowledge of AD.

Aged↗
PubMed2006

Cortical reorganization during PASAT task in MS patients with preserved working memory functions.

Cortical reorganization in multiple sclerosis (MS) is defined as a compensatory mechanism which requires MS patients to overactivate specific brain areas in order to perform the task as controls. To investigate this process with the Paced Auditory Serial Addition Test (PASAT) task, we selected 15 MS patients who performed the PASAT task within-normal limits and 10 healthy controls. Once selected, we used functional magnetic resonance imaging (fMRI) to investigate brain areas involved in PASAT performance in both groups. Results showed that the task activated the left frontal (BA6 and 9) and parietal cortex (BA7 and 40) in both groups, but MS patients showed a stronger activation in the left prefrontal cortex (BA9, 44 and 45) when compared with controls. These results confirmed those obtained post hoc by Audoin et al. [Audoin, B., Ibarrola, D., Ranjeva, J.P., Confort-Gouny, S., Malikova, I., Ali-Chérif, A.M., Pelletier, J., Cozzone, P., et al., 2003. Compensatory cortical activation observed by fMRI during cognitive task at the earliest stage of MS. Hum. Brain Mapp. 20, 51-58], and we interpreted this as showing true cortical reorganization.

Adult↗
PubMed2001

[Polyps of the biliary tract: is their preoperative diagnosis possible?].

Bile duct polyps are a very uncommon cause of obstructive jaundice. We present our experience of three patients diagnosed in the last 10 years. Initial presentation usually takes the form of obstructive jaundice associated with abdominal pain, which simulates biliary lithiasis. The diagnosis is usually surgical. Although in some cases radiological studies and endoscopic retrograde cholangiopancreatography (ERCP) may sometimes detect bile duct polyps, exact diagnosis before surgery is very unusual. The radiological signs that suggest the existence of a bile duct polyp in the ERCP seem to be the presence of repletion defects, fixed unilaterally to the biliary conduit, without meniscus and without circumferential stenosis of the affected conduit. The most frequently found polyps are fibroinflammatory, and less frequently adenomatous.

Adult↗
PubMed2001

[Consensus conference on consultation times in neurology. Recommendations on consultation times in neurology outpatients care in Spain].

INTRODUCTION: Developing recommendations about consultation times in neurology helps plan the endowment of human resources and can contribute to homogenize and improve quality of health-care. OBJECTIVES: To elaborate recommendations on the consultation times needed to obtain enough quality neurology visits. MATERIAL AND METHOD: We used consensus search techniques, in particular the Community Impression technique. An ad hoc committee developed a preliminary proposal which was later discussed during a unlimited attendance working meeting and eventually voted by members of the Spanish Society of Neurology. The committee drew up a final consensus report after analysing the debate results and counting the ballots. FINAL RECOMMENDATION: "It is necessary that the Spanish Society of Neurology establishes and recommends standardized consultation times for neurology outpatients visits in Spain. These standardized values refer to consultation time per patient, both in the first and follow-up visits, in a General Neurology Outpatients Clinic. Moreover, there must be considered 'recommendable times' on one hand, and 'minimal required times' on the other hand. Any time value below the minimal required time means that the consultation duration does not fulfill the minimal requirements needed to warrant a care with acceptable quality for the patient". These recommendations are: Time for first consultation. Recommendable time: 45 minutes (Minimal required time: 25 minutes). Time for follow-up consultation. Recommendable time: 20 minutes (Minimal required time: 15 minutes).

Humans↗
PubMed2000

Identification, cloning, and characterization of a major cat flea salivary allergen (Cte f 1).

An 18 kDa protein isolated from saliva of the cat flea, Ctenocephalides felis, elicits a positive intradermal skin test (IDST) in 100 and 80% of experimental and clinical flea allergic dogs, respectively. Using solid-phase enzyme-linked immuno assay (ELISA), this protein detected IgE in 100 and 80% of experimental and clinical flea allergic dogs, respectively. A cDNA (pFSI) encoding a full-length Cte f 1 protein was isolated from a C. felis salivary gland cDNA library, using a combination of PCR and hybridization screening. This cDNA is 658 bp in length, and contains an open reading frame of 528 bp. The open reading frame encodes a protein of 176 amino acids, consisting of an 18 amino acid signal sequence and a 158 amino acid mature protein. The calculated molecular weight and pI of the mature protein are 18106 Da and 9.3, respectively. The protein, named Cte f 1, is the first novel major allergen described for canine flea allergy. Recombinant Cte f 1 (rCte f 1) was expressed in Escherichia coli, Pichia pastoris and baculovirus infected Trichoplusia ni cells. Approximately, 90% of the rCte f 1 expressed in E. coli accumulated in insoluble inclusion bodies, which could be refolded to a soluble mixture of disulfide isomers with partial IgE binding activity. Small quantities of an apparently correctly refolded form of rCte f 1, which had IgE binding activity equal to the native antigen, was isolated from the soluble fraction of E. coli cells. However, P. pastoris and baculovirus infected insect cells expressed and secreted a fully processed, correctly refolded and fully active form of rCte f 1. Mass spectrometry analysis of the active forms of rCte f 1confirmed that eight intact disulfide bonds were present, matching the number observed in the native allergen. The relative ability of rCte f 1 to bind IgE in the serum of flea allergic animals, produced in these three expression systems, matched that of the native allergen. Competition ELISA demonstrated that approximately 90% of the specific IgE binding to native Cte f 1 could be blocked by the different forms of rCte f 1.

Alkylation↗
PubMed1999

T-DNA transfer to maize plants.

Agrobacterium-mediated transformation is the method of choice to engineer desirable genes into plants. Here we describe a protocol for demonstrating T-DNA transfer from Agrobacterium into the economically important graminaceous plant maize. Expression of the T-DNA-located GUS gene was observed with high efficiency on shoots of young maize seedlings after cocultivation with Agrobacterium.

DNA, Bacterial↗
PubMed1999

High-frequency percussive ventilation improves oxygenation in patients with ARDS.

STUDY OBJECTIVES: To evaluate changes in respiratory and hemodynamic function of patients with ARDS and requiring high-frequency percussive ventilation (HFPV) after failure of conventional ventilation (CV). DESIGN: Retrospective case series. SETTING: Surgical ICU (SICU) and medical ICU (MICU) of an academic county facility. MEASUREMENTS AND RESULTS: Thirty-two consecutive patients with ARDS (20 from SICU, 12 from MICU) who were unresponsive to at least 48 h of CV and were switched to HFPV were studied. Data on respiratory and hemodynamic parameters were collected during the 48 h preceding and the 48 h after institution of HFPV and compared. Between the period of CV and the period of HFPV, the ratio of PaO2 to the fraction of inspired oxygen (F(IO2)) increased ([mean+/-SE] 130+/-8 vs. 172+/-17; p = 0.027), peak inspiratory pressure (PIP) decreased (39.5+/-1.7 vs. 32.5+/-1.9 mm Hg; p = 0.002), and mean airway pressure(MAP) increased (19.2+/-1.2 vs. 27.5+/-1.4 mm Hg; p<0.001). The rate of change of PaO2/F(IO2) per hour was also significantly improved between the two periods. The same changes in PaO2/F(IO2), PIP, and MAP were observed when the last value recorded while the patients were on CV was compared with the first value recorded after 1 h of HFPV. This improvement was sustained but not amplified during the hours of HFPV. The patterns of improvement in these three parameters were similar in SICU and MICU patients as well as in volume-control and pressure-control patients. There were no changes in hemodynamic parameters. CONCLUSION: The HFPV improves oxygenation by increasing MAP and decreasing PIP. This improvement is achieved soon after institution of HFPV and is maintained without affecting hemodynamics.

Adult↗
PubMed1997

[De-novo reversible stenoses in tortuous arteries during coronary angioplasty due to the accordion effect. A clinical case and review of the literature].

During the performance of PTCA, the operator must be able to differentiate true complications from pseudocomplications. Mechanical coronary shortening and vessel wall invagination due to accordion effect, "pseudo-transection", dissection, coronary spasm, and localized thrombosis are sources of iatrogenic obstruction during angioplasty. We report a case in which straightening of a right tortuous coronary artery during angioplasty produced an iatrogenic lesion that has a typical invaginate appearance. Conservative management is indicated in the absence of definitive angiographic aspect of vessel trauma, because they disappear after withdrawal of angioplasty equipment or adequate management of the guidewire.

Angioplasty, Balloon, Coronary↗
PubMed1995

Intracellular Agrobacterium can transfer DNA to the cell nucleus of the host plant.

Agrobacterium tumefaciens is a Gram-negative, soil-borne bacterium responsible for the crown gall disease of plants. The galls result from genetic transformation of plant cells by the bacteria. Genes located on the transferred DNA (T-DNA), which is part of the large tumor-inducing (Ti) plasmid of Agrobacterium, are integrated into host plant chromosomes and expressed. This transfer requires virulence (vir) genes that map outside the T-DNA on the Ti plasmid and that encode a series of elaborate functions that appear similar to those of interbacterial plasmid transfer. It remains a major challenge to understand how T-DNA moves from Agrobacterium into the plant cell nucleus, in view of the complexity of obstacles presented by the eukaryotic host cell. Specific anchoring of bacteria to the outer surface of the plant cell seems to be an important prelude to the mobilization of the T-DNA/protein complex from the bacterial cell to the plant cell. However, the precise mode of infection is not clear, although a requirement of wounded cells has been documented. By using a microinjection approach, we show here that the process of T-DNA transfer from the bacteria to the eukaryotic nucleus can occur entirely inside the plant cell. Such transfer is absolutely dependent on induction of vir genes and a functional virB operon. Thus, A. tumefaciens can function as an intracellular infectious agent in plants.

Journal Article↗
PubMed1995

Hypoglossal nerve conduction study by transcranial magnetic stimulation in normal subjects.

The introduction of transcranial magnetic stimulation has allowed the study of conduction in the proximal portions and central pathways of the cranial nerves. A study is made of cranial nerve XII with transcranial magnetic stimulation at two levels, cortical and cisternal, registering the motor evoked potential by means of surface electrodes in contact with the upper face of the tongue. Motor evoked potentials were constantly observed on cortical stimulation, in a painless, easy, and reproducible way, with mean values of 10.84 +/- 1.14 milliseconds (latency) and 7.81 +/- 1.14 mV (amplitude). Motor evoked potentials were unconstant and showed reduced amplitudes on cisternal stimulation, with mean values of 4.72 +/- 0.62 milliseconds and 0.83 +/- 1.26 mV. The magnetic stimulation technique allows the study of the entire motor pathway of cranial nerve XII (motor cortex-medulla, motoneuron-muscle). The method is efficient, noninvasive, painless, and easily reproduced, and it comes close to being an ideal clinical conduction study technique for this cranial nerve.

Adult↗
PubMed1994

Combined pressure control/high frequency ventilation in adult respiratory distress syndrome and sickle cell anemia.

Acute chest syndrome complicating sickle cell anemia may progress to adult respiratory distress syndrome despite appropriate therapy. Extra-alveolar air leaks may complicate the care of these patients as conventional mechanical ventilation becomes increasingly difficult. We successfully treated a child with sickle cell anemia, acute chest syndrome, adult respiratory distress syndrome, and severe extra-alveolar air leaks using a new combined mode ventilatory approach: pressure control with high-frequency ventilation.

Anemia, Sickle Cell↗
PubMed1993

T-DNA transfer to maize cells: histochemical investigation of beta-glucuronidase activity in maize tissues.

Agrobacterium tumefaciens is routinely used to engineer desirable genes into dicotyledonous plants. However, the economically important graminaceous plant maize is refractory to tumor induction by inoculation with virulent strains of A. tumefaciens. Currently, the only clearcut evidence for transferred DNA (T-DNA) transport from Agrobacterium to maize comes from agroinfection. To study T-DNA transfer from Agrobacterium to maize cells in a virus-free system, we used here the beta-glucuronidase (GUS; EC 3.2.1.31) gene as a marker. GUS expression was observed with high efficiency on shoots of young maize seedlings after cocultivation with Agrobacterium carrying the GUS gene. Agrobacterium virulence mutants, incapable of transferring T-DNA to dicot tissue, were shown to be deficient in eliciting GUS expression in maize. Hence, expression of the T-DNA-located GUS gene in maize cells is strictly dependent on Agrobacterium-mediated DNA transfer. Histochemical staining of maize shoots revealed GUS expression located mainly in the leaves and the coleoptile.

Journal Article↗
PubMed1993

Accessory nerve electroneurography by magnetic stimulation in normal subjects.

An electroneurographic study was made of the accessory nerve in 15 healthy subjects by conventional peripheral electrical stimulation and transcranial magnetic stimulation at three different levels: cortical contralateral (frontoparietal), homolateral occipital and at the base of the skull. The motor evoked potential (MEP) obtained by magnetic stimulation at the skull base exhibited greater latency and amplitude than that recorded by conventional peripheral electrical stimulation. The MEP obtained by stimulating at occipital level again exhibited a greater latency than that corresponding to skull base stimulation, but the amplitude was smaller. Finally, the MEP resulting from cortical stimulation failed to appear uniformly in all of the individuals studied. Its amplitude was smaller than in the previous cases, with a mean latency of 11.76 ms and a central conduction time of 7.5 ms. The magnetic stimulation technique allowed the efficient, painless, non-invasive and easily reproducible study of the motor pathway of the spinal nerve over its entire trajectory (motor cortex-motor neuron-muscle).

Accessory Nerve↗
PubMed1992

Transient global amnesia after cerebral angiography with iohexol.

We describe a patient without a previous history of migraine or epilepsy and with no known vascular risk factors, who suffered subarachnoid haemorrhage. During vertebral angiography using nonionic contrast medium (iohexol), spasm of the basilar artery was seen. The patient suffered transient global amnesia. Angiography 3 months later with the same contrast medium was normal and produced no further deficit. This case lends support to the supposed ischaemic aetiology of transient global amnesia; in patients without other evidence of cerebrovascular disease, arterial spasm may be responsible.

Amnesia, Retrograde↗