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Biomedical subjects

A Campos

Publications and source records attributed to A Campos.

At least 19 recordsLinked to original sources
PubMed2003

Upper lateral cartilage transposition in the surgical management of nasal valve incompetence.

INTRODUCTION: The treatment of nasal valve dysfunction is very controversial and many otorhinolaryngologists do not always take surgery into consideration. The purpose of this paper is to present the author's surgical technique and the description of 13 patients on which it may work. MATERIAL AND METHOD: Thirteen cases presenting with nasal obstruction secondary to nasal valve dysfunction are reviewed. All of the patients presented with internal valvulary incompetence and in three of them an alar collapse was associated. Diagnosis was achieved by means of the clinical findings and physical examination. An open rhinoplasty approach was employed. The surgical technique consisted in a transposition of the upper lateral cartilage over the alar cartilage. In the three patients with alar collapse a fixation graft from the septal cartilage was also employed. RESULTS: Nasal obstruction and valvular incompetence seemed improved in all of the cases. CONCLUSION: Upper lateral cartilage transposition seems to be an adequate method to solve the nasal valve incompetence.

Adult↗
PubMed2002

[Intelligent system to perform a diagnostic protocol for lymphatic invasion in laryngeal cancer].

Laryngeal carcinoma is the most frequent malignant tumour in head and neck. Node invasion is known to be one of the most important prognostic factors. The aim of this study has been to design an intelligent system to perform a diagnostic algorithm of metastasic neck nodes. 122 clinical reports of patients diagnosed of laryngeal carcinoma in our department have been reviewed. The compiled data have been: tumor site, T stage, N stage (clinical, after CT scan and post-surgery). The method used to design the intelligent system has been the ID3, which is able to generate a minimal decision tree. Palpation has been the variable that has given more information about node invasion. CT has proved to be more efficient in supraglottic tumours. ID3 method has shown to be useful in performing diagnostic algorithms, specially when the number of cases and diagnostic tests are high.

Adult↗
PubMed2002

Anapsos (Polypodium leucotomos) modulates lymphoid cells and the expression of adhesion molecules.

Anapsos is a medical prescription registered in the Health Ministry of Spain, that is obtained from the rhizomes of the fern Polypodium leucotomos. An immunomodulating effect of Anapsos on certain lymphocyte subsets and cytokines has already been described in the literature. The current study extends and supports part of the aforementioned results of the product on the immune system, showing the ability of Anapsos to stimulate proliferation and activation of T and natural killer lymphocytes, as well as an important down-regulating effect on CD11, CD18 and CD62-L adhesion molecules, both on peripheral blood mononuclear cells and on U-937 and HL-60 cell lines.

Adjuvants, Immunologic↗
PubMed2001

High frequency of constitutive alkali-labile sites in mouse major satellite DNA, detected by DNA breakage detection-fluorescence in situ hybridization.

DNA breakage detection-fluorescence in situ hybridization (DBD-FISH) is a new procedure for detecting and quantifying DNA breaks and alkali-labile sites in single cells. Cells trapped within an agarose matrix are deproteinized and treated with an alkaline unwinding solution that transforms DNA breaks and alkali-labile sites into single-strand DNA (ssDNA) motifs starting from the end of the break. These ssDNA motifs are susceptible to being hybridized with whole genome or specific DNA probes, and detected using current FISH procedures. As DNA breaks increase in a target region, more ssDNA is produced and more DNA probe hybridizes, thus increasing the FISH signal, which may be captured and analyzed using a digital image analysis system. This increase can be reflected in the surface area, mean and whole fluorescence intensity of the signal. When intact mouse splenocytes were processed with this technique using a whole genome probe, a very strong background signal was evident when compared with human blood leukocytes. In fact, when using 0.03M NaOH as the alkaline unwinding solution at 22 degrees C for 2.5min, the whole fluorescence intensity from mice cells was 50 times higher than that from human cells, thus suggesting the existence of a high frequency of constitutive alkali-labile sites in the DNA from mouse cells. Furthermore, when alkaline unwound mouse cells were simultaneously hybridized with the whole genome probe (FITC-revealed, green) and a major satellite DNA probe (Cy-3-labeled, red) both signals appeared co-localized. This result demonstrates that the high frequency of constitutive alkali-labile sites detected in the mouse genome is mainly located in the major satellite DNA sequences, resembling the findings from human 5bp classical satellite DNA sequences.

Alkalies↗
PubMed2001

The lipid charge density at the bilayer surface modulates the effects of melittin on membranes.

The influence of melittin on two DMPA membrane systems at pH 4.2 and 8.2 has been investigated by solid-state 31P and 2H NMR, as a function of temperature and peptide concentration. Melittin promotes greater morphological changes for both systems in the fluid phase, the effect being larger at pH 4.2. Close inspection of fatty acyl chain dynamics suggests that some parallels can be drawn between the DMPA/melittin at pH 8.2 and PC/melittin systems. In addition, at pH 8.2 a direct neutralization at the interface of one of the lipid negative charges by a positive charge of the peptide occurs, as can be monitored by 31P NMR at the molecular level. For the system at pH 4.2 and at high temperature, a lipid-to-peptide molar ratio of 30 is sufficient to transform the whole system into an isotropic phase, proposed to be inverted micelles. When the system is cooled down towards the gel phase one observes an intermediate hexagonal phase in a narrow range of temperature.

Aniline Compounds↗
PubMed2001

[Outbreak of Q fever and seroprevalence in a rural population from Soria Province].

BACKGROUND: The aim of this study was to describe an outbreak of acute fever in a rural town from Soria (Spain) in the spring of 1998 and to know the prevalence of IgG antibodies to Coxiella burnetii in this population. METHODS: 1. Outbreak of Q fever: epidemiological, clinical and analytical data were obtained by standardised questionnaire and the clinical records from all clinical cases. These cases were confirmed by complement fixation test.2. Seroprevalence: 253 sera were chosen by not probabilistic sampling of convenience of sera samples collected between 1 September 1996 and 28 February 1999. Were regarded as positive anti-phase II C. burnetii IgG titles by indirect inmunoflourescence assay equal or higher to 1/80. RESULTS: 1. A total of 14 cases of Q fever with a mean age of 21.5 +/-3.1 years were confirmed. 64% presented pneumonia and in 36% the symptoms were nonspecific. No patient had direct contact with animals but near to the town there were 4 flocks with 2,614 sheeps overall. 2. The seroprevalence was 60% (95% confidence interval: 54-66). The seroprevalence was not increased with the outbreak (p > 0.05). CONCLUSION: The high prevalence of antibodies to C. burnetii in this population shows that this area is hyperendemic for such infection, but generally is asymptomatic or clinical signs are extremely mild because no cases of Q fever had been reported in the years before. Probably indirect exposure to flocks of sheep was the source of infection and transmission mechanism airborne.

Adolescent↗
PubMed2001

Crystal structure of the global regulator FlhD from Escherichia coli at 1.8 A resolution.

FlhD is a 13.3 kDa transcriptional activator protein of flagellar genes and a global regulator. FlhD activates the transcription of class II operons in the flagellar regulon when complexed with a second protein FlhC (21.5 kDa). FlhD also regulates other expression systems in Escherichia coli. We are seeking to understand this plasticity of FlhD's DNA-binding specificity and, to this end, we have determined the crystal structure of the isolated FlhD protein. The structure was solved by substituting seleno-methionine for natural sulphur-methionine in FlhD, crystallizing the protein and determining the structure factor phases by the method of multiple-energy anomalous dispersion (MAD). The FlhD protein is dimeric. The dimer is tightly coupled, with an intimate contact surface, implying that the dimer does not easily dissociate. The FlhD monomer is predominantly alpha-helical. The C-termini of both FlhD monomers (residues 83-116) are completely disrupted by crystal packing, implying that this region of FlhD is highly flexible. However, part of the C-terminus structure in chain A (residues 83-98) was modelled using a native FlhD crystal. What is seen in chain A suggests a classic DNA-binding, helix-turn-helix (HTH) motif. FlhD does not bind DNA by itself, so it may be that the DNA-binding HTH motif becomes rigidly defined only when FlhD forms a complex with some other protein, such as FlhC. If this were true, it might explain how FlhD exhibits plasticity in its DNA-binding specificity, as each partner protein with which it forms a complex could allosterically affect the binding specificity of its HTH motif. A disulphide bridge is seen between the unique cysteine residues (Cys-65) of FlhD native homodimers. Alanine substitution at Cys-65 does not affect FlhD transcription activator activity, suggesting that the disulphide bond is not necessary for either dimer stability or this function of FlhD. Electrostatic potential analysis indicates that dimeric FlhD has a negatively charged surface.

Crystallization↗
PubMed2001

Extensive alanine scanning reveals protein-protein and protein-DNA interaction surfaces in the global regulator FlhD from Escherichia coli.

FlhD and FlhC are the transcriptional activators of the flagellar regulon. The heterotetrameric complex formed by these two proteins activates the transcription of the class II flagellar genes. The flagellar regulon consists not only of flagellar genes, but also of the chemotactic genes and some receptor proteins. Recently, a connection between the flagellar regulon and some virulence genes has been found in some species. Furthermore, FlhD, but not FlhC, regulates another non-flagellar target. As a first attempt to understand the mechanism of the flagellar transcriptional activation by FlhD and FlhC, the structure of FlhD has been solved. In order to understand the mechanism of the action of FlhD when it regulates the flagellar genes, we conducted site-directed mutagenesis based on its three-dimensional structure. Six interaction surfaces in the FlhD dimer were mapped by alanine scanning mutagenesis. Two of them are surface clusters formed by residues His-2, Asp-28, Arg-35, Phe-34 and Asn-61 located at each side of the dimer core. The other four are located in the flexible arms of the dimer. The residues Ser-82, Arg-83, Val-84, His-91, Thr-92, Ile-94 and Leu-96 are located at this region. All these residues are involved in the FlhD/FlhC interaction with the exception of Ser-82, Arg-83 and Val-84. These three residues affect the DNA-binding ability of the complex. The three-dimensional topology of FlhD and the site-directed mutagenesis results support the hypothesis of FlhC as an allosteric effector that activates FlhD for the recognition of the DNA.

Alanine↗
PubMed2001

Genotype/phenotype observations in African Americans with Bartter syndrome.

BACKGROUND: Two Bartter syndrome phenotypes have been described, and molecular analyses demonstrate mutations in 1 of 3 genes encoding ascending limb of Henle transporters. We report phenotypic observations in 5 African American children with Bartter syndrome in the context of a distinct genotype. METHODS: Mutation analyses were performed in 5 unrelated African American children with Bartter syndrome. These results were correlated to clinical and laboratory data. Calcium metabolism was evaluated with a bone disk bioassay. RESULTS: Mutation analyses demonstrated homozygous deletion of the ClC-Kb gene in all children. Two children had polyhydramnios and premature birth; the others were born at term and presented with failure to thrive or dehydration. All receive indomethacin, spironolactone, and potassium chloride with improved but borderline hypokalemia. Growth has improved with therapy, but height SD scores range from -3.9- to -1.4. Urinary calcium excretion is normal, and bone disk bioassay shows no abnormal calciotropic activity. No patient had nephrocalcinosis, but renal sonograms show loss of corticomedullary differentiation. CONCLUSIONS: African Americans with Bartter syndrome genotyped to date have homozygous deletion of ClC-Kb Clinical observations in our patients include partial correction of hypokalemia and suboptimal growth despite therapy. Abnormal calciotropic activity and nephrocalcinosis are not seen, but renal ultrasounds are abnormal.

Anion Transport Proteins↗
PubMed2001

Scanning electron microscopy and calcification in amelogenesis imperfecta in anterior and posterior human teeth.

Teeth fragments from members of a family clinically and genetically diagnosed as having amelogenesis imperfecta were studied by scanning electron microscopy and X-ray microprobe analysis to establish the morphological patterns and the quantitative concentration of calcium in the enamel of anterior (canine, incisor) and posterior (premolar and molar) teeth. The prism patterns in the enamel of teeth from both regions were parallel or irregularly decussate, with occasional filamentous prisms accompanied by small, irregularly rounded formations. Prismless enamel showed the R- and P-type patterns. Calcium levels in enamel of amelogenesis imperfecta and control teeth differed significantly between anterior and posterior teeth, indicating that the factors that influence normal mineralization in different regions of the dental arch are not altered in the process of amelogenesis imperfecta.

Amelogenesis Imperfecta↗
PubMed2001

In situ and in vitro senescence induced by KCl stress: nutritional imbalance, lipid peroxidation and antioxidant metabolism.

Sunflower (Helianthus annuus L. cv. SH222) plants and calli were exposed to KCl stress for three weeks. Calli were more tolerant to KCl than plants. KCl stress decreased NO(-)(3), Mn, Fe and B levels in whole plants and P, Ca and Mg in shoots. NO(-)(3), P, Ca, Mg, Mn, and B levels decreased in 100 mM-stressed calli. Chlorophyll content, F:(m) and (F:(m)-F:(0))/F:(m) ratio decreased in stressed leaves, while F:(0) increased only in leaves exposed to severe stress (100 and 150 mM). Membrane permeability and lipid peroxidation increased in plants under all stress conditions and in 100 and 150 mM stressed calli, but remained unchanged in 25 mM stressed calli. Salt stress also induced changes relating to antioxidant enzymes: plants under all stress conditions showed a decrease in catalase, peroxidase and SOD activities. Calli under moderate stress (25 mM KCl) showed an increase of catalase, peroxidase and SOD activities, but the activities of peroxidase and SOD decreased when calli were exposed to higher KCl concentrations. The decrease of antioxidant enzyme activities is in tune with lipid peroxidation and membrane permeability increases. On the other hand, calli adapted for 6 months to 100 mM KCl showed an increase of these enzyme activities compared to unstressed calli, while MDA production and membrane permeability were not significantly affected.

Antioxidants↗
PubMed2000

Binding of a fluorescent dansylcadaverine-substance P analogue to negatively charged phospholipid membranes.

We have investigated the binding of a new dansylcadaverine derivative of substance P (DNC-SP) with negatively charged small unilamellar vesicles composed of a mixture of phosphatidylcholine (PC) and either phosphatidylglycerol (PG) or phosphatidylserine (PS) using fluorescence spectroscopic techniques. The changes in fluorescence properties were used to obtain association isotherms at variable membrane negative charges and at different ionic strengths. The experimental association isotherms were analyzed using two binding approaches: (i) the Langmuir adsorption isotherm and the partition equilibrium model, that neglect the activity coefficients; and (ii) the partition equilibrium model combined with the Gouy-Chapman formalism that considers electrostatic effects. A consistent quantitative analysis of each DNC-SP binding curve at different lipid composition was achieved by means of the Gouy-Chapman approach using a peptide effective interfacial charge (v) value of (0.95 +/- 0.02), which is lower than the physical charge of the peptide. For PC/PG membranes, the partition equilibrium constant were 7.8 x 10(3) M(-1) (9/1, mol/mol) and 6.9 x 10(3) M(-1) (7/3, mol/mol), whereas for PC/PS membranes an average value of 6.8 x 10(3) M(-1) was estimated. These partition equilibrium constants were similar to those obtained for the interaction of DNC-SP with neutral PC membranes (4.9 x 10(3) M(-1)), as theoretically expected. We demonstrate that the v parameter is a determinant factor to obtain a unique value of the binding constant independently of the surface charge density of the vesicles. Also, the potential of fluorescent dansylated SP analogue in studies involving interactions with cell membranes is discussed.

Cadaverine↗
PubMed2000

Central nervous system (CNS) tuberculosis following allogeneic stem cell transplantation.

Tuberculosis is an uncommon infectious complication after stem cell transplantation. We report a patient who presented with a brain mass, 3 months after pulmonary tuberculosis had been diagnosed and while he was receiving triple antituberculous therapy. He had extensive chronic GVHD. The diagnosis was made after biopsy of the lesion. The cerebral mass was excised, antituberculous treatment was maintained and the patient made a complete neurologic recovery. Six months later, he died of gram-negative septic shock. Mycobacterial infections should be considered in allograft recipients with chronic GVHD and solid lesions in the brain. Bone Marrow Transplantation (2000) 25, 567-569.

Brain↗
PubMed2000

Influence of human wet cerumen on the growth of common and pathogenic bacteria of the ear.

The available data on the effect of human wet cerumen on bacterial growth are not conclusive. Nevertheless it is widely accepted that cerumen has a bactericidal effect. In this study the activity of human wet cerumen on bacterial growth was assessed by applying cerumen suspensions to bacterial cultures. Bacterial counts were performed before and after application of cerumen suspensions. A total of 383 assays was carried out with 73 pools of cerumen that were tested against cultures of Staphylococcus aureus, Staphylococcus epidermidis, Corynebacterium spp., Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa and Serratia marcescens. An increase in growth occurred much more frequently than a decrease in growth in almost every microrganism tested, with the mean increase percentage being much higher than the mean decrease percentage, except in the case of S. aureus. The largest average growth increase was obtained with E. coli. The largest average decrease in bacterial growth was recorded with S. marcescens. Our study does not support the conception of a decrease in bacterial growth produced by humen wet cerumen. In vitro, the most observable effect was in fact an increase in microbial growth.

Adolescent↗