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Biomedical subjects

A Delgado

Publications and source records attributed to A Delgado.

At least 73 records · Page 4Linked to original sources
PubMed1998

Modulation of the function of the signal receptor domain of XylR, a member of a family of prokaryotic enhancer-like positive regulators.

The XylR protein controls expression from the Pseudomonas putida TOL plasmid upper pathway operon promoter (Pu) in response to aromatic effectors. XylR-dependent stimulation of transcription from a Pu::lacZ fusion shows different induction kinetics with different effectors. With toluene, activation followed a hyperbolic curve with an apparent K of 0.95 mM and a maximum beta-galactosidase activity of 2,550 Miller units. With o-nitrotoluene, in contrast, activation followed a sigmoidal curve with an apparent K of 0.55 mM and a Hill coefficient of 2.65. m-Nitrotoluene kept the XylR regulator in an inactive transcriptional form. Therefore, upon binding of an effector, the substituent on the aromatic ring leads to productive or unproductive XylR forms. The different transcriptional states of the XylR regulator are substantiated by XylR mutants. XylRE172K is a mutant regulator that is able to stimulate transcription from the Pu promoter in the presence of m-nitrotoluene; however, its response to m-aminotoluene was negligible, in contrast with the wild-type regulator. These results illustrate the importance of the electrostatic interactions in effector recognition and in the stabilization of productive and unproductive forms by the regulator upon aromatic binding. XylRD135N and XylRD135Q are mutant regulators that are able to stimulate transcription from Pu in the absence of effectors, whereas substitution of Glu for Asp135 in XylRD135E resulted in a mutant whose ability to recognize effectors was severely impaired. Therefore, the conformation of mutant XylRD135Q as well as XylRD135N seemed to mimic that of the wild-type regulator when effector binding occurred, whereas mutant XylRD135E seemed to be blocked in a conformation similar to that of wild-type XylR and XylRE172K upon binding to an inhibitor molecule such as m-nitrotoluene or m-aminotoluene.

Adenosine Triphosphatases↗
PubMed1997

Patients with geleophysic dysplasia are not always geleophysic.

We report on two boys with facial anomalies, small hands and feet, joint contractures, thick skin, unusual tiptoe gait and lysosome-like inclusions in the hepatocytes, compatible with a diagnosis of geleophysic dysplasia (GD). One of them also had fibrosis and fatty degeneration of the liver. In both, the facial appearance was different and neither had short stature nor progressive cardiac valvular disease. These clinical findings, consistent with a mild form of GD, support the notion that this disorder may have a broader spectrum than initially suspected.

Abnormalities, Multiple↗
PubMed1997

A study of LiF GR-200 for radiotherapy mailed dosimetry.

A study of the measurement performance of LiF GR-200 for radiotherapy mailed dosimetry is presented. The study was carried out in the practical working conditions of a mailed system where a lengthy delay between dosimeter preparation and the final readout can occur. Prompt and delayed TL measurements were employed to determine, among other characteristics, the reusability and the stability during storage at room temperature. From the results obtained it can be concluded that GR-200, although producing dose results adequate for mailed dosimetry, does not improve the performance attainable with LiF TLD-100.

Calibration↗
PubMed1997

In vivo construction of a hybrid pathway for metabolism of 4-nitrotoluene in Pseudomonas fluorescens.

Pseudomonas fluorescens 410PR grows on 4-nitrobenzoate but does not metabolize 4-nitrotoluene. The TOL pWW0 delta pm plasmid converts 4-nitrotoluene into 4-nitrobenzoate through its upper pathway, but it does not metabolize 4-nitrobenzoate. P. fluorescens 410PR(pWW0 delta pm) transconjugants were isolated and found to be able to grow on 4-nitrotoluene. This phenotype was stable after growth for at least 300 generations without any selective pressure. P. fluorescens 410PR(pWW0 delta pm) converted 4-nitrotoluene into 4-nitrobenzoate via 4-nitrobenzylalcohol and 4-nitrobenzaldehyde. 4-Nitrobenzoate was metabolized via 4-hydroxylaminobenzoate and finally yielded NH4+ and 3,4-dihydroxybenzoate, which was mineralized.

Biotransformation↗
PubMed1996

Butterfly vertebra.

A 41-year-old man with low back pain and lumbar disc disease was found to have L-3 butterfly vertebra on imaging studies as an incidental finding. This uncommon congenital anomaly of the vertebral column is usually asymptomatic and of no clinical significance. Awareness of this deformity and its imaging features is important diagnostically.

Abnormalities, Multiple↗
PubMed1996

First use of cognitive algorithms in investigations under compensated gravity.

In the present paper the use of cognitive algorithms for solving a wide spectrum of problems which often arise in investigations under compensated gravity is suggested. Applying such algorithms in the preparation and performance of experiments provides a substantial assistance to the experimentator as the behaviour of complex processes can be described and predicted correctly even when unexpected perturbations occur. Furthermore, an essential advantage of cognitive computing consists in the fact that the description and optimisation of the processes considered are possible also in such cases in which the corresponding basic equations are not known or not treatable practically. For convenience, the basic ideas of cognitive algorithms are discussed here. Due to their special relevance for investigations under compensated gravity algorithms based on fuzzy logic (FL) and artificial neuronal networks (ANN) are elucidated more in detail. In order to illustrate some advantages of cognitive computing exemplary results for the flow field induced by coaxial rotating disks are given. This represents the first attempt to use the benefits provided by cognitive algorithms in investigations under compensated gravity. The flow field between rotating disks plays an important role not only in experiments under compensated gravity but also in a wide range of terrestrial applications. A comparison of the results found by solving the Navier-Stokes equations and those from the prediction performed by ANN adequately trained shows an excellent agreement. However, the calculation times needed by the ANN are significantly smaller than that of the direct numerical simulation. Therefore, the real time prediction of the results from a running experiment seems to be possible.

Algorithms↗
PubMed1995

[Influence of the organizational model on user satisfaction].

OBJECTIVE: To identify in Health Centres (HC), doctors' offices and out-patient clinics the variables among the use, the doctor and organisation, which most affect satisfaction of the Primary Care (PC) user. DESIGN: A descriptive crossover study. SETTING: PC level in three Andalusian cities. PATIENTS AND OTHER PARTICIPANTS: A sample of groups of 460 users of out-patient clinics and doctors' offices and 400 from HCs, all in an urban environment. MEASUREMENTS AND MAIN RESULTS: Three questionnaires were used to gather the independent variables of organisation, doctor and use, and also the dependent variable, or satisfaction, in three dimensions: professional competence, personal qualities and accessibility. The reliability of the scale of satisfaction was analysed using Crombach's alpha; and discriminative capacity, using the Edwards test. The effect of the variables of doctor, user and organisation on HCs and doctors' offices / out-patient clinics was analysed separately with multiple regression. The determination coefficient of the variables for the user at doctors' offices / out-patient clinics was higher than the same variables in HCs (p < 0.0001), age being the variable which most affected satisfaction, both in HCs and doctors' offices / out-patient clinics. The determination coefficients for the regressions of the variables of doctor and organisation were higher in HCs than in doctors' offices / outpatient clinics (p < 0.001) in both cases - with the use of the clinical records being the primary variable in both organisations. CONCLUSIONS: It appears that the organisational model of HCs offers more possibilities of increasing user satisfaction by modifying determined features of the doctor and the organisation.

Adult↗
PubMed1995

Single amino acids changes in the signal receptor domain of XylR resulted in mutants that stimulate transcription in the absence of effectors.

The XylR protein positively controls expression from the Pseudomonas putida TOL plasmid sigma 54-dependent "upper" pathway operon promoter (Pu) and the xylS gene promoter (Ps), in response to the presence of aromatic effectors. Two mutant XylR regulators able to stimulate transcription from Pu and Ps in the absence of effectors were isolated. These mutants exhibited single point mutations, namely Asp135-->Asn and Pro85-->Ser. Both mutations are located in the amino termini domain of XylR, which is thought to be responsible for interactions with effectors. The effector profile of XylRP85S was similar to that of wild-type XylR protein; however, XylRD135N exhibited an altered pattern of effector recognition: with m-nitrotoluene it stimulated transcription from the Pu promoter above the high basal level, whereas this nitroarene inhibited the wild-type regulator. Previous work (Delgado, A., and Ramos, J.L. (1994) J. Biol. Chem. 269, 8059-8062) showed that residue 172 was involved in effector interactions, as mutant XylRE172K also recognized m-nitrotoluene. However, double mutant XylR135N/E172K did not stimulate transcription in the absence of effector, but retained the ability to stimulate transcription with m-nitrotoluene. Transcription mediated by XylRD135N and XylRP85S from Pu::lacZ was analyzed in detail. Like the wild-type regulator, XylRD135N and XylRP85S required sigma 54 for full transcription activation, but in contrast with the wild-type regulator, XylRD135N, but not XylRP85S, stimulated transcription from Pu in the absence of the integration host factor protein. XylRD135N, also in contrast with XylR and XylRP85S, mediated transcription from a mutant Pu promoter that lacked one of the upstream regulator binding sites (delta UAS1), but not when both upstream regulator binding sites were deleted. The level of autoregulation of XylRD135N was at least 2-fold higher than that found with the wild-type XylR regulator and the mutant XylRP85S.

Bacterial Proteins↗
PubMed1995

[Rothmund-Thomson syndrome and osteosarcoma].

BACKGROUND: The Rothmund-Thomson syndrome is a hereditary dermatosis frequently accompanied by less well-known non dermatologic features including osteogenic sarcoma. CASE REPORT: A girl developed the classical dermatologic features of the Rothmund-Thomson syndrome since the first months of life. When she was 6 years old, she suffered from painful limitation of motion of her left leg. X-rays, MNR imaging and bone scintigraphy showed typical features of osteosarcoma of the distal portion of the femur. Diagnosis was confirmed by histologic examination through open biopsy. The search for metastatic lesions was negative. The patient was given chemotherapy and the tumor was resected 45 days later followed by postoperative chemotherapy. CONCLUSION: About 12 similar cases of osteosarcoma have been reported in patients with the Rothmund-Thomson syndrome. A review of literature allows to recognize some peculiar features of such association.

Biopsy↗
PubMed1995

Application of glow curve analysis methods to radiotherapy mailed dosimetry with LiF TLD-100.

This paper presents the results obtained in a study of LiF TLD-100 performance for mailed dosimetry in radiotherapy, using glow curve analysis of TL evaluation and reusable chips. An excellent reusability is assured by a simple thermal treatment of 1 h at 400 degrees C followed by a controlled and reproducible cooling to room temperature that accurately reproduces the sensitivity of the detectors. Particular attention was devoted to studying sensitivity changes during room temperature storage of TLD-100 detectors. These changes can be one of the major sources of uncertainty in mailed dosimetry, where long intervals can occur between detector preparation, irradiation and readout. Based on the features of the individual peak evolution during storage a rather simple method to correct for these sensitivity modifications is proposed. The analysis of the different influential factors permitted us to estimate a combined uncertainty for the measurement of absorbed doses within the 0.5-4 Gy range of 1.0%.

Humans↗
PubMed1994

[Hypertension programs and the risk of ischemic cardiopathy].

OBJECTIVE: To find the risk of ischaemic cardiopathy in a sample of hypertension patients. DESIGN: Crossover study. SETTING: Almanjáyar and Cartuja Health Centres (Granada). PATIENTS AND OTHERS TAKING PART: 202 Hypertension patients included in the programme and belonging to three practices in the above-mentioned centres. MEASUREMENTS AND MAIN RESULTS: We determined the variable of age, gender, overall cholesterol, cholesterol-HDL, TAS, HVI in ECG and we recorded the number of check-ups over the last year, tobacco consumption and diabetes. The 47% of men and 46% of women presented a RCI higher than that of the population as a whole for their age and gender group, in spite of treatment and intervention on these risk factors. Men between 45 and 64 presented higher RCI than women (p < 0.001) and had fewer check-ups. CONCLUSION: We consider that our programme did not sufficiently affect the prevention of ischaemic cardiopathy. It was especially deficient in the monitoring of men between 45 and 64 years. We think that the maintenance of programmes oriented round particular pathologies, instead of integrated programmes, is not sufficient to reduce ischaemic cardiopathy, which clearly has a multiple-cause origin.

Adult↗
PubMed1994

Genetic evidence for activation of the positive transcriptional regulator Xy1R, a member of the NtrC family of regulators, by effector binding.

The Xy1R protein positively controls expression from the Pseudomonas putida TOL plasmid sigma 54-dependent Pu and Ps promoters, in response to the presence of aromatic effectors such as m-xylene, m-methylbenzyl alcohol, and p-chlorobenzaldehyde in the culture medium. Xy1R also autoregulates its own synthesis. A mutant Xy1R regulator called Xy1R7 was isolated after nitrosoguanidine mutagenesis of the wild-type gene and phenotypic selection for mutants that had acquired the ability to recognize m-nitrotoluene, a nitroarene that is not an effector for the wild-type regulator. The mutant regulator exhibited a single point mutation that resulted in a change in codon 172 (GAA-->AAA), which should result in a Glu-->Lys change in the polypeptide chain. The effector profile of the mutant regulator was determined by measuring beta-galactosidase from a fusion of the Pu promoter to a promoterless lacZ gene. The results showed that the mutant regulator had acquired the ability to recognize m-nitrotoluene, and retained the wild-type regulator's ability to recognize most of the wild-type effectors. Full transcriptional activation of the Pu promoter by Xy1R7, as with the wild-type Xy1R protein, requires its full modular structure, namely the sigma 54 recognition site, the integration host factor binding site, and the upstream activation sequences. The Xy1R7 regulator did not stimulate transcription from the Ps promoter in response to the presence of its effectors, and autoregulated its own synthesis at low levels.

Amino Acid Sequence↗
PubMed1994

Urinary profile of androgen metabolites at different stages of pubertal development in a population of sporting male subjects.

In this cross-sectional study on 140 subjects, several testosterone and epitestosterone metabolites have been analyzed by gas chromatography-mass spectrometry associated with stable isotope dilution, a technique requested for doping analysis in general, and detection of exogenous testosterone supply in particular. Urinary excretions of luteinizing hormone, testosterone and epitestosterone glucuronides and sulfates, as well as glucuronides of 5-androstene-3 beta, 17 alpha-diol, 5 alpha- and 5 beta-androstane-3 alpha, 17 alpha-diol and the corresponding 17 beta-isomers, present similar patterns of increase throughout pubertal development, from stage 1 up to stage 5. Excretion levels are significantly different in general between stages 1, 2, 3 and 4, the highest percentage increase being observed between stages 3 and 4. None of the ratios of testosterone to epitestosterone glucuronides are beyond the threshold value of 6, where testosterone abuse by athletes is suspected. No particular pubertal stage exceeded this critical value with a probability higher than p = 0.006, a value that was determined on the whole population. This is consistent with the non-significant differences between correlation slopes of regression curves, relating either testosterone or epitestosterone glucuronide to chronological age. The ratio of testosterone glucuronide to luteinizing hormone increases significantly throughout puberty and this might be a limitation to the widespread use of this ratio for the detection of testosterone misuse.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Changes in the characteristics of anaerobic exercise in the upper limb during puberty in boys.

The aim of this study was to examine the relationships between the characteristics of anaerobic exercise in the upper limb and important indicators of growth and developmental age such as height (h), body mass (mb), skeletal age (SA), plasma testosterone (T) and pubertal stage (PS). We used the force-velocity (F-v) relationship test in a population of 66 healthy adolescent male junior jockeys, with considerable variation in these indicators but of the same physical fitness level (training effect). The mean values of the maximal anaerobic power (Wan,max) were 391 (SD 93) W. The values of the variables in the F-v relationship for the upper limb were only slightly or uncorrelated with the chronological age, but highly correlated with h, mb and SA (P < 0.001). The correlation with T was less significant. Using ANOVA a highly significant effect of PS on the variables in the F-v relationship was found (P < 0.001). The absolute or relative (normalized to mb) increase in Wan,max during puberty was greater from PS P2 and P3 than at other stages. Therefore PS would appear to be a significant factor for developmental changes in anaerobic characteristics during puberty in the adolescent. The PS P3 determined only by public hair might be an easy and accurate indicator for sports category classification of adolescents during puberty.

Adolescent↗
PubMed1993

Influence of the doctor's gender in the satisfaction of the users.

This study was carried out in the framework of a wider research project concerning the degree of patient satisfaction with the various types of primary health care. We have studied the relationship among the gender of the doctor, the gender of the patient and the type of primary health care center involved. In 1 type of primary care center (health centers) the medical staff work as a team, whereas in the other (ambulatory care services), the doctor works alone. The survey was conducted among 86 doctors and 860 patients from urban areas in Andalusia, Spain. The degree of patient satisfaction was tested on Likert scales. Both male and female patients attended by female doctors were more satisfied than those attended by male doctors (P < 0.005). Both male and female patients were attended in equal proportions by both male and female doctors (P > 0.20). Overall patient satisfaction values were not affected by the patient's gender (P > 0.40). In comparing overall satisfaction among patients according with the doctor's gender and type of primary health care center, there was a greater degree of satisfaction with female doctors working in health centers (P < 0.01) and no difference existed in ambulatory care services in this area.

Adult↗