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Biomedical subjects

A Delgado

Publications and source records attributed to A Delgado.

At least 55 records · Page 3Linked to original sources
PubMed2001

Delayed partial liquid ventilation shows no efficacy in the treatment of smoke inhalation injury in swine.

In an earlier neonatal porcine model of smoke inhalation injury (SII), immediate postinjury application of partial liquid ventilation (PLV) had dramatic beneficial effects on lung compliance, oxygenation, and survival over a 24-h period. To explore the efficacy of PLV following SII, we treated animals at 2 and 6 h after SII and followed them for 72 h. Pigs weighing 8-12 kg were sedated and pharmacologically paralyzed, given a SII, and placed on volume-cycled, pressure-limited ventilation. Animals were randomized to three groups: group I (+SII, no PLV, n = 8), group II (+SII, PLV at 2 h, n = 6), and group III (+SII, PLV at 6 h, n = 7). Ventilatory parameters and arterial blood gasses were obtained at scheduled intervals. The PLV animals (groups II and III) followed a worse course than group I (no PLV); PLV groups had higher peak and mean airway pressures, oxygenation index, and rate-pressure product (a barotrauma index) and lower lung compliance and arterial partial pressure of oxygen-to-inspired oxygen fraction ratio (all P < 0.05). PLV conferred no survival advantage. The reported beneficial effects of PLV with other models of acute lung injury do not appear to extend to the treatment of SII when PLV is instituted in a delayed manner. This study was not able to validate the previously reported beneficial effects of PLV in SII and actually found deleterious effects, perhaps reflecting the predominance of airway over alveolar disease in SII.

Animals↗
PubMed2000

DNA breakage detection-FISH (DBD-FISH) in human spermatozoa: technical variants evidence different structural features.

Non-irradiated and X-irradiated (80 Gy) human spermatozoa were processed for in situ DNA breakage detection-FISH (DBD-FISH) of the whole genome, following two alternative variations of the basic technique. In the first, cells were initially incubated in the alkaline unwinding solution for transformation of DNA breaks into single-stranded DNA (ssDNA) to be hybridized, followed by the lysing solutions for protein removal. In the second, incubation in the lysing solutions was carried out before the denaturation step. The first approach yielded two subpopulations. While most sperm nuclei were faintly labeled and had chromocenters, a small subpopulation was strongly and homogeneously labeled, due to extensive DNA breakage. X-ray exposure increased the surface and mean fluorescence intensity. Otherwise, when the denaturation step was performed after protein extraction, all sperm nuclei yielded strong and dispersed FISH signals. Protein removal allows access of the unwinding solution to the DNA, which has abundant alkali-labile sites, and thus gives rise to large areas of ssDNA that are labeled by FISH. X-ray exposure increased the dispersion of FISH signals but decreased their mean fluorescence intensity. A linear dose-response was generated using the second experimental variant, being 30 Gy the lowest dose for detecting induction of damage by X-rays in mature sperm chromatin. These results indicate that DBD-FISH is not only useful for in situ detection of DNA breakage but also for revealing structural features of chromatin.

DNA↗
PubMed2000

Transcatheter occlusion of complex atrial septal defects.

Percutaneous device occlusion of secundum atrial septal defects (ASDs) is becoming an accepted alternative to surgical closure. This method allows us to evaluate patients with complex conditions for treatment. From a total of 70 patients with ASD evaluated for percutaneous closure, we selected for analysis 28 who had complex conditions. The mean age was 36+/-23 yr (range, 4-72). Six had heart failure, and of these six, three had atrial fibrillation. At cardiac catheterization, the pulmonary pressure was 47+/-24 mm Hg, and the QP/QS was 1.7+/-0.4; two patients had bidirectional shunt and systemic pulmonary pressure. Two patients received a buttoned device and 26 an Amplatzer septal occluder. The groups of patients with complex conditions were separated into the following groups. Group I (n = 4) underwent combined treatment of associated anomalies. Two patients had pulmonary stenosis, one had mitral stenosis, and one had an aortic root-left atrium fistula. They were treated in or during with the same procedure by combined transcatheter techniques (balloon valvuloplasty and fistula occlusion) before ASD occlusion. Group II (n = 9) had multiple defects (cribiform or two separate holes). They were treated with a single device in five instances and with two separate devices in four cases. Group III (n = 14) had large (32+/-3 mm) single defects. Nine of them underwent successful implantation using a device 33+/-3 mm in diameter; in the remaining five patients the device was removed because of instability. Group IV (n = 3) had residual defects after previous partial device occlusion. All three defects were successfully occluded with a second device. No movement or interference with the first device was observed. Group V (n = 6) had severe pulmonary hypertension (86+/-16 mm Hg). Immediately after ASD occlusion we observed significant relief in these patients (67+/-14 mm Hg; P<0.01). There were no major complications; all 23 patients with successful implants were discharged without symptoms 2-7 days later; one patient with atrial fibrillation recovered sinus rhythm. The follow-up (8+/-5 mo) Doppler echo study showed complete ASD occlusion in 22 patients and a peak pulmonary pressure of 30+/-14 mm Hg. We conclude that transcatheter occlusion of ASDs is an effective and safe treatment for patients with complex anatomic or physiopathologic conditions, as evaluated by short-term follow-up.

Adolescent↗
PubMed2000

Inhibitory control of the GABAergic transmission in the rat neostriatum by D2 dopamine receptors.

The aim of the study was to determine the role of dopamine on the GABAergic input to striatal projection neurons. Accordingly, the effect of the activation of dopamine D2-like receptors on GABA-mediated depolarizing postsynaptic potentials evoked in striatal slices by local stimulation was studied. Conventional intracellular recording techniques were used to record the synaptic responses. The experiments were done in the presence of 6-cyano-7-nitroquinoxaline-2,3-dione (20 microM) and (+)-2-amino-5-phosphonovaleric acid (40 microM) to block the participation of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate/kainate and N-methyl-D-aspartate receptors in the synaptic response. The GABAergic nature of the response was assessed by its potentiation by pentobarbital (50 microM) and by its elimination by bicuculline or picrotoxin. At 100 nM, a concentration already maximal, dopamine inhibited by 55% the GABAergic synaptic response. The inhibitory effect was totally blocked by the selective antagonist of D2-like receptors, sulpiride (100 nM). The dopamine inhibition was observed only in one-third of the studied neurons and was concentration dependent (IC50 = 14 nM). The inhibition was not associated with changes in the input resistance or any other membrane property. In addition, dopamine (50 nM) reduced the frequency but not the amplitude of spontaneous, bicuculline-sensitive depolarizing postsynaptic potentials. The D2-like receptor agonist quinpirole also dose-dependently (IC50 = 10 nM) inhibited the GABAergic synaptic response. As with dopamine, the inhibition did not change the membrane properties of the studied neurons. In addition, the quinpirole induced inhibition of the GABA response was accompanied by increased paired-pulse facilitation. The results indicate that D2-like receptors located on intrinsic GABAergic terminals in the rat striatum exert an inhibitory control of the GABAergic input to striatal projection neurons. The dopaminergic effect would be translated in facilitation of the firing of the neurons upon the arrival of the cortical input.

Animals↗
PubMed2000

Radiolabelled biodegradable microspheres for lung imaging.

The effect on lung accumulation of modifying the surface compositions of (99m)Tc poly(lactide-co-glycolide) (PLGA) and (99m)Tc poly(ethylene glycol)-poly(lactide-co-glycolide) (PEG-PLGA) microspheres with different surfactants was assessed after intravenous injection into rats. Microspheres were prepared with PLGA or PEG-PLGA by the emulsion solvent evaporation method using polyvinyl alcohol (PVA), polyethylene glycol (PEG), albumin (BSA) or poloxamer 188 as surfactant, in the external aqueous phase. Commercial human albumin microspheres (Sferotec((R)), HAM) were used as reference. According to the European Pharmacopeia, >80% of (99m)Tc-HAM in the size range 10-50 microm, must be accumulated in the lung 15 min after intravenous administration. By modifying the surfactant, the resulting lung accumulation was 99% for (99m)Tc-HAM, and more than 50% for PLGA microspheres prepared with poloxamer 188 (1 and 4%), reaching 67% with 8% Poloxamer 188 and around 30-39% for PLGA and PEG-PLGA microspheres prepared with the other surfactants. PLGA microspheres made with 8% poloxamer 188 gave good quality lung images under a gamma camera for the first few minutes, subsequently liver radioactivity masked lung images.

Animals↗
PubMed2000

Detection of interferon regulatory factor-1 in lamina propria mononuclear cells in Crohn's disease.

BACKGROUND: The transcription factor, interferon regulatory factor (IRF)-1, is stimulated by interferon-gamma and regulates the expression of several genes implicated in the pathogenesis of inflammatory bowel disease, including interleukin-6, major histocompatibility complex class II molecules, and inducible nitric oxide synthase. Interferon regulatory factor-1 also stimulates naive CD4+ T-cells to differentiate into T-helper-1 cells, the T-cell subset that appears to be upregulated in Crohn's disease. The purpose of this study was to examine the expression of IRF-1 in the nuclei of lamina propria mononuclear cells in situ in colonoscopic biopsy specimens from pediatric patients with Crohn's disease, in patients with ulcerative colitis, and in control patients with no histopathologic abnormalities. METHODS: Archival paraffin-embedded tissue sections were obtained from 25 pediatric patients with Crohn's disease, 6 patients with ulcerative colitis, and 12 control patients who had undergone colonoscopy. Tissue sections were stained with polyclonal rabbit anti-human antisera to IRF-1 and horseradish-peroxidase-conjugated, biotinylated, goat anti-rabbit secondary antibody. Slides were scored and scores compared among patient groups using analysis of variance. RESULTS: Patients with Crohn's disease had significantly higher IRF-1 scores (95% confidence interval [CI], 1.70-2.04) than patients with ulcerative colitis (95% CI, 0.92-1.23) or control subjects (95% CI, 1.11-1.52). CONCLUSIONS: Increased expression of IRF-1 in lamina propria mononuclear cells from patients with Crohn's disease may be relevant to the pathogenesis of Crohn's disease.

Adolescent↗
PubMed2000

Validity of self reported utilisation of primary health care services in an urban population in Spain.

STUDY OBJECTIVE: To assess the validity and factors related with the validity of self reported numbers of visits to a primary health care centre, in comparison with the recorded number. DESIGN: Cross sectional study. SETTING: The urban area served by the Zaidín-Sur Primary Health Care Centre (Granada, Spain). PARTICIPANTS: Two population samples (236 high users and 420 normal users) who were seen at the centre from 1985 to 1991 were interviewed in 1993. MAIN RESULTS: A net tendency to overreport the actual number of visits was observed. Absolute concordance between self reported and recorded utilisation decreased as time interval lengthened, although this mainly reflected the increase in maximum variability both with time interval length and with the number of recorded visits. Corrected Spearman rho coefficients obtained between the number of self reported and recorded visits ranged from 0.602 for the two weeks before the interview to 0.678 for the year before. Regression slopes of self reported utilisation upon recorded utilisation did not change between periods. In multiple regression analyses the actual number of visits was the main factor associated with both underreporting and overreporting. Older age was also significantly associated with underreporting. Poor health status and high satisfaction with health care were significantly associated with overreporting. CONCLUSIONS: There was a substantial degree of inaccuracy in self reported utilisation, with a net tendency to overreport the number of visits. In relative terms, however, accuracy of self reports did not seem to decrease appreciably as the recall time lengthened. To compare the accuracy of different measures, it is important to take into account the maximum variability of each one. Otherwise, contradictory results may be obtained.

Adolescent↗
PubMed2000

Developmental brain anomalies in children with attention-deficit hyperactivity disorder.

The pathoetiology of attention-deficit hyperactivity disorder (ADHD) has been considered to be neurodevelopmental, yet the timing and processes involved are not clearly identified. Neurodevelopmental brain anomalies have been associated with a variety of psychiatric conditions. However, they have never been evaluated in a population of patients with ADHD. This study was designed to determine the frequency of specific developmental brain anomalies in a group of children with ADHD (n = 85; mean age, 10.9 years) and healthy control children (n = 95; mean age, 11.7 years) by visually inspecting brain magnetic resonance imaging scans. Compared to controls, the ADHD group showed an increase in frequency of two developmental anomalies: (1) gray-matter heterotopia, a neuronal migration anomaly, in 2 of 85 patients versus 0 of 95 controls; and (2) posterior fossa abnormality (excess cerebrospinal fluid in the posterior fossa) in 8 of 85 patients versus 2 of 95 controls. There were no differences in frequency of enlarged cavum septi pellucidi between the two groups. These findings support and extend the idea that ADHD is of developmental origin, and further suggest that the timing of aberrant brain development could be in early gestation.

Adolescent↗
PubMed2000

Combined percutaneous atrial septal defect occlusion and pulmonary balloon valvuloplasty in adult patients.

Severe pulmonary stenosis in association with a large atrial septal defect is uncommon. When these 2 conditions are present, significant left-to-right shunt is often prevented by the outflow obstruction, which protects the pulmonary bed until adulthood. This report shows our initial experience of percutaneous treatment of both congenital malformations, either staged or combined in the same procedure, in 2 adult patients whose treatments yielded effective atrial septal defect occlusion and right ventricular pressure relief that persisted at mid-term follow-up. Although these opposite procedures (opening and closing) have been applied as isolated methods of treatment, this preliminary experience appears to demonstrate the feasibility and effectiveness of a combined percutaneous treatment.

Adult↗
PubMed1999

PLG microparticles stabilised using enteric coating polymers as oral vaccine delivery systems.

Novel poly(dl-lactide-co-glycolide) microparticles for oral vaccine delivery were formulated using the enteric polymers Eudragit L100-55 and carboxymethylethylcellulose (CMEC) as stabilisers. To serve as a control, microparticles were also produced using the conventional PVA surfactant. In all three cases the antigen, ovalbumin (OVA)-loaded microparticles produced were less than 5 microm in diameter and had a spherical, smooth rounded appearance. The presence of surfactants at the microparticle surface was demonstrated by the surface analysis techniques, XPS and SSIMS. Incubation of microparticles with solutions of pepsin or trypsin led to the removal of a proportion of the antigen associated with all three systems. However, in three CMEC-stabilised microparticle formulations and one of three Eudragit formulations, a high percentage of the associated antigen was protected from removal by a solution of pepsin at pH 1.2 compared with the PVA-stabilised microparticles. In addition, with certain CMEC and Eudragit formulations a degree of protection was also afforded to the associated OVA against removal by trypsin at pH 7.4. Following the incubation of microparticles in simulated gastric fluid a higher percentage of intact antigenic OVA was detected in microparticles stabilised using CMEC than in the PVA- and Eudragit- stabilised formulations. Oral immunisation of mice with OVA-loaded microparticles stabilised using either of the three surfactants led to the induction of specific serum IgG and salivary IgA antibodies. Significantly higher levels of specific salivary IgA antibody to OVA were measured in mice immunised with the CMEC-stabilised microparticles than with the other two formulations. This novel approach in PLG microparticle formulation may have potential in increasing the efficacy of microparticulate systems for the oral administration of vaccines.

Administration, Oral↗
PubMed1999

[Patient preference and stereotype about the gender of the family physician].

OBJECTIVE: To study the preferences of patients on the gender of the physician when consulting for particular health problems; and to know the gender stereotypes that patients assign to physicians. DESIGN: Cross-sectional study. SETTING: Five teaching health centres in Granada (Spain). PATIENTS: Randomised sample of patients that consulted 10 female and 20 female physicians during three months (17 patients per physician), for alfa = 5%, beta = 80%, to detect a difference of 12% between male and female physicians. MEASUREMENTS AND MAIN RESULTS: We used a questionnaire adapted from Fennema (Family Medicine Dept., Wisconsin University, 1990) that was administered by interviewers after the consultancy, following a previous pilot study. Preference and stereotype scales comprised 10 items, with five reponses (neutral mid-point). Differences were analysed with chi 2 with correction for continuity. Non-reponders (33%) were replaced, and their age and sex did not bias the study results. Responders were 210 males (40.9%) and 304 women (59.1%). For "flux in penis/vagina" and "haemorrhoids" 50-60% of the patients preferred a physician of the same sex, with the remainder expressing no preference. The women preferred female physicians for family problems (23%) and depression (23%). The male physicians were more often perceived to be unorganised than were the females (24% vs. 5%, p < 0.0005), while the female physicians were more often described as humane (15% vs. 10%, p < 0.0005). Characteristics expressing technical competence were more often attributed to the male physicians than to the females, while those expressing empathy were more often attributed to the female physicians. CONCLUSIONS: Patients prefer physicians of the same gender for some health problems and not for others. Patients assign gender stereotypes to physicians. These findings will permit a better interpretation of doctor-patient relationships.

Cross-Sectional Studies↗
PubMed1999

Blink reflex recovery in facial weakness: an electrophysiologic study of adaptive changes.

OBJECTIVE: To study the electrophysiologic effects of unilateral facial weakness on the excitability of the neuronal circuitry underlying blink reflex, and to localize the site of changes in blink reflex excitability that occur after facial weakness. BACKGROUND: Eyelid kinematic studies suggest that adaptive modification of the blink reflex occurs after facial weakness. Such adaptations generally optimize eye closure. A report of blepharospasm following Bell's palsy suggests that dysfunctional adaptive changes can also occur. METHODS: Blink reflex recovery was evaluated with paired stimulation of the supraorbital nerve at different interstimulus intervals. Comparisons were made between normal control subjects and patients with Bell's palsy who either recovered facial strength or who had persistent weakness. RESULTS: Blink reflex recovery was enhanced in patients with residual weakness but not in patients who recovered facial strength. Facial muscles on weak and unaffected sides showed enhancement. In patients with residual weakness, earlier blink reflex recovery occurred when stimulating the supraorbital nerve on the weak side. Sensory thresholds were symmetric. CONCLUSION: Enhancement of blink reflex recovery is dependent on ongoing facial weakness. Faster recovery when stimulating the supraorbital nerve on the paretic side suggests that sensitization may be lateralized, and suggests a role for abnormal afferent input in maintaining sensitization. Interneurons in the blink reflex pathway are the best candidates for the locus of this plasticity.

Adaptation, Physiological↗
PubMed1999

Value of intravascular ultrasound in the assessment of coronary pseudostenosis during coronary interventions.

Coronary pseudostenosis (PS) are increasingly visualized during coronary interventions. In many patients PS are readily recognized by a characteristic angiographic pattern, but in other cases the diagnosis remains difficult. The value of intravascular ultrasound (IVUS) in the study of PS remains unknown. In this study, IVUS was used to assess the morphologic appearance of the vessel wall in 10 consecutive patients showing images of PS during coronary interventions. Mean age of the group was 60+/-12 years and two patients were female. IVUS was performed with a motorized pullback system to assess lumen, plaque, and total vessel cross-sectional areas. Measurements were performed both at the site of PS and at the distal reference segment. PS were always located on angled coronary segments. In one patient no lumen narrowing was detected with IVUS at the site of PS. In the remaining nine patients, however, a very localized elliptic-shaped lumen narrowing was demonstrated. As compared with the distal reference segment, coronary lumen (6.3+/-2.2 vs. 12.7+/-4.8 mm2, P < 0.001) and total vessel area (11.9+/-3.3 vs. 16.1+/-6.1 mm2, P < 0.05) were smaller at the site of PS. Severe lumen asymmetry was also documented at this site. In addition, a characteristic image of a flattened, three-layered wall, overlying a hypoechogenic space, was visualized in five patients. This unique pattern was considered the correlate of a partial coronary intussusception. PS induced some resistance to the advancement of catheters in two patients and temporary flow impairment in two additional patients. However, in every case, the image of PS disappeared once the guidewire was removed. Thus, at sites with PS, IVUS allows ruling out severe atherosclerosis and coronary dissections. In addition, IVUS also provides important diagnostic clues, including the image of intussusception, for making the correct diagnosis of this benign entity.

Aged↗
PubMed1999

Psychosocial and health belief variables associated with frequent attendance in primary care.

BACKGROUND: The reasons for high use of primary care, and in particular the role of psychosocial factors, remain unclear. METHODS: We identified and interviewed 236 frequent attenders and 420 normal users, matched by age and sex, of a public Health Centre in Granada, Spain. Users were questioned about mental health (GHQ-28), social support (Duke-UNC-11), family dysfunction (family APGAR) and health beliefs (health belief model, locus of health control and medical care expectations). We also measured a set of individual, social and illness variables. RESULTS: Multiple logistic regression analyses showed that mental health was the main factor associated with frequent attender status (odds ratio = 3.1; 2.4-3.9). The association was stronger than that between frequent attender status and perceived illness, and between the former and reported chronic illness. Family dysfunction and perceived susceptibility to and severity of disease were also significantly but more weakly associated with frequent attender status. Affective support was more strongly associated with FA status than was confidant support, but both associations disappeared when mental health and family function were controlled for. CONCLUSIONS: Our findings document the association of psychosocial factors and primary health care use. We suggest that the effective management of mental health problems from a family-based approach may reduce primary health care high use.

Adolescent↗
PubMed1999

Signal-dependent phosphorylation of the membrane-bound NarX two-component sensor-transmitter protein of Escherichia coli: nitrate elicits a superior anion ligand response compared to nitrite.

The Nar two-component regulatory system, consisting of the dual sensor-transmitters NarX and NarQ and the dual response regulators NarL and NarP, controls the expression of various anaerobic respiratory pathway genes and fermentation pathway genes. Although both NarX and NarQ are known to detect the two environmental signals nitrate and nitrite, little is known regarding the sensitivity and selectivity of ligand for detection or activation of the sensor-transmitters. In this study, we have developed a sensitive anion-specific in vitro assay for NarX autophosphorylation by using Escherichia coli membranes highly enriched in the full-length NarX protein. In this ATP- and magnesium-dependent reaction, nitrate elicited a greater signal output (i.e., NarX autophosphorylation) than did nitrite. Nitrate stimulation occurred at concentrations as low as 5 microM, and the half-maximal level of NarX autophosphorylation occurred at approximately 35 microM nitrate. In contrast, nitrite-dependent stimulation was detected only at 500 microM, while 3.5 mM nitrite was needed to achieve half-maximal NarX autophosphorylation. Maximal nitrate- and nitrite-stimulated levels of NarX phosphorylation were five and two times, respectively, over the basal level of NarX autophosphorylation. The presence of Triton X-100 eliminated the nitrate-stimulated kinase activity and lowered the basal level of activity, suggesting that the membrane environment plays a crucial role in nitrate detection and/or regulation of kinase activity. These results provide in vitro evidence for the differential detection of dual signaling ligands by the NarX sensor-transmitter protein, which modulates the cytoplasmic NarX autokinase activity and phosphotransfer to NarL, the cognate response regulator.

2,4-Dinitrophenol↗
PubMed1998

Craniometadiaphyseal dysplasia, wormian bone type.

We report on a 4-year-old boy with craniometadiaphyseal dysplasia (CMDD), wormian bone type. Component manifestations include a large head with prominent forehead, skull changes showing multiple wormian bones, wide long tubular bones without the usual metaphyseal flare, wide and short tubular bones without the normal diaphyseal constriction, and wide ribs and clavicles. In addition to these findings, the propositus, his brother, his father, and a paternal aunt all have parietal protuberances, which seem not related to CMDD. Parental consanguineity supports the autosomal recessive transmission of the condition.

Abnormalities, Multiple↗