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Biomedical subjects

M Palma

Publications and source records attributed to M Palma.

At least 19 recordsLinked to original sources
PubMed2007

Hospitalised osteoporotic vertebral fractures in Spain: analysis of the national hospital discharge registry.

UNLABELLED: This population-based study reveals clinical and epidemiologic characteristics of hospitalised osteoporosis-related vertebral fractures and indicates an association with a substantial hospital burden in Spain. These data provide a basis for assessing the impact of these fractures on the Spanish health-care system and to estimate future care requirements. INTRODUCTION: Vertebral fractures (VF) are recognised as the most frequent complication of osteoporosis. Our objective was to determine the clinico-epidemiological characteristics and health-care burden of hospitalised VF in Spain. METHOD: From the 2002 National Hospital Discharge Register, records for all osteoporosis-related VF in the Spanish population aged >or=30 years and over were retrieved. Diagnostic categories included the ICD-9-CM codes 805 and 733.xx. Population data were drawn from the National Statistics Institute. RESULTS: In total, 7,100 records were eligible for analysis. According to Deyo-adapted Charlson index, 62% of cases had no associated comorbidity. VF were the cause of hospitalisation in 52% of cases. Overall in-hospital mortality was 3.5%. Men had higher adjusted mortality than women. Mean hospital stay was 11.4+/-0.2 days. Identified cases amounted to a hospitalisation rate of 2.76 cases per 10,000 population aged >or=30 years. Direct inpatient hospital costs exceeded 41 million euros and accounted for 0.078% of Spanish expenditure on hospitalisations and specialised care in 2002. CONCLUSIONS: The national discharge database reveals epidemiological features of hospitalised osteoporosis-attributable VF and indicates an association with a substantial hospital burden in Spain. Our data provide a basis for assessing the impact of these fractures on the Spanish health-care system and to estimate future care requirements.

Adult↗
PubMed2006

Determination of trans-resveratrol in grapes by pressurised liquid extraction and fast high-performance liquid chromatography.

A study has been made of the extraction of trans-resveratrol from grapes using pressurised liquids (PLE); for this, the first stage was to determine the stability of this compound during extractions at different temperatures (50, 100, 150 degrees C), with quantitative recoveries being obtained up to 150 degrees C. By employing solid-phase extraction (SPE) it was possible to retain this compound and separate it from other interfering substances present in the grape. The method developed comprises a sequential extraction of the sample adsorbed (0.5g) on a polystyrene-divinylbenzene based sorbent in the extraction chamber, first with water at 40 degrees C and 40atm of pressure (three cycles of 5min), and then with methanol at 150 degrees C and 40atm (three cycles of 5min). The trans-resveratrol content of the methanolic extract is determined by means of liquid chromatography. A rapid (5min) chromatographic method employing a monolithic column, with fluorescence detection, has been developed; for this, the conditions for detection of the compound were optimised (excitation at 310nm and emission at 403nm). The analytical parameters of the method of chromatographic analysis developed have been calculated: linear range (0.11-2.75mg/L), detection limit (0.003mg/L), quantification limit (0.004mg/L). Using this method, three varieties of grape have been analysed and the concentration of trans-resveratrol in these has been determined.

Antineoplastic Agents, Phytogenic↗
PubMed2006

Generation of DC-based vaccine for therapy of B-CLL patients. Comparison of two methods for enriching monocytic precursors.

BACKGROUND: The generation of Ag-loaded DC under good manufacturing practice (GMP) conditions is logistically challenging and further compounded when the starting precursors need to be purified from B-CLL patients who have overwhelming numbers of circulating B-CLL cells and decreased numbers of monocytes. METHODS: We have previously demonstrated that DC with endocytosed B-CLL apoptotic bodies are powerful stimulators of anti-leukemic T cells. In this study we compared counterflow elutriation and immunomagnetic separation for enriching monocyte precursors, and evaluated the feasibility of generating DC from B-CLL patients and the effects of cryopreservation. RESULTS: Monocyte yield from a single leukapheresis product of a B-CLL patient varied from 1 x 108 to 10 x 108 total cells, from which 40-200 x 106 mature DC could be produced. Adequate numbers of monocytes could not be enriched from one patient with 0.2% monocytes in the leukapheresis product, and the target of 50 x 106 DC was barely achieved in another patient with 0.9% monocytes in the pheresed cells. These results suggested that successful production of DC is dependent on a minimum frequency of 1% CD14(+) monocytes in the leukapheresis product. Cryopreservation of tumor cell-loaded DC yielded a recovery rate of 86+/-4.4% upon thawing, with a total viability of 90+/-2.8%. Most importantly, cryopreserved Ag-loaded DC retained their morphology, phenotype and function. DISCUSSION: The results demonstrate that adequate numbers of functional DC required for clinical therapy can be generated from patients who have >1% of CD14(+) monocytes in the leukapheresis product. Moreover, Ag-loaded DC can be cryopreserved and recovered without significant change in phenotype or function.

Cancer Vaccines↗
PubMed2006

Strain rate imaging: data acquisition and postrocessing.

Several studies already demonstrated the clinical relevance of strain rate imaging. Unfortunately, so far only few echolaboratories are using this technique in their clinical practice. This is mainly due to the lack of information on how to perform a standard strain rate imaging study. Thus, the aim of the present review is to provide the bases and methodology to perform a correct strain rate study.

Echocardiography↗
PubMed2005

Determination of phenolics in cosmetic creams and similar emulsions.

A new method for the analysis of phenolics in cosmetic creams has been developed, based on a systematic study of the extractability of five phenolic compounds from such emulsions. A solid-liquid extraction using ultrasound was applied as a prior stage to the chromatographic determination of phenolics in the extracts. Three solvents, hexane, methanol and water, were used as extracting agents. These solvents permit both the de-emulsification of the creams and the extraction of phenolics. A factorial fractional experimental design was developed to analyse the influence in the extraction process of five different extraction variables: ultrasound horn, temperature, extracting volume, cycle and amplitude of ultrasounds. Graphic analysis of results revealed the variables with most influence in the extraction, as well as the interactions between the variables. Finally, the influence of the extraction time and the sample quantity were also studied. With this new method, phenolics can be extracted from silicone-based cosmetic creams in 10 min, using 50 degrees C as extraction temperature. RSDs (n=6) calculated ranged from 1.5% for ferulic acid to 6.5% for epicatechin. Recoveries of between 88.9% for gallic acid and 98.4% for caffeic acid were obtained.

Cosmetics↗
PubMed2001

Stability of phenolic compounds during extraction with superheated solvents.

The stability of nine phenolic compounds in the extraction with superheated methanol at different temperatures (40, 50, 100 and 150 degrees C) has been tested. The evolution of the same compounds in boiling methanol (65 degrees C) in contact with air was also determined. All the assayed phenolic compounds were stable under the extraction conditions with the exception of catechin and epicatechin (recoveries: 87.4% for catechin and 86.0% for epicatechin at 150 degrees C and 94.1% for epicatechin at 100 degrees C). Phenolic compounds kept at the boiling point of methanol (65 degrees C) showed lower recoveries: gentisic acid (85.5%), syringic aldehyde (92.8%), catechin (63.7%) and epicatechin (63.4%). Extraction with superheated solvents was also applied to the extraction of phenolic compounds from solid wastes of the winemaking process.

Hot Temperature↗
PubMed2001

Extracellular fibrinogen-binding protein, Efb, from Staphylococcus aureus blocks platelet aggregation due to its binding to the alpha-chain.

Extracellular fibrinogen-binding protein (Efb) secreted by Staphylococcus aureus has previously been shown to contribute to pathogenesis in a rat wound infection model. Also antibodies against Efb exhibited a protective effect in a mouse mastitis model. The interaction between Efb and fibrinogen is divalent, with one binding site within the N-terminal repeat region in Efb and one at the C terminus. In this study we show that the distal D domain of fibrinogen contains at least one of the binding domains recognized by Efb. Efb stimulates fibrinogen binding to ADP-activated platelets. Furthermore, Efb inhibits ADP-induced, fibrinogen-dependent platelet aggregation in a concentration-dependent manner. This implies that Efb modifies platelet function by amplifying a non-functional interaction between fibrinogen and platelets. Efb recognizes the A alpha-chain of the D fragment of fibrinogen. The RGD sequence on the A alpha-chain is located close to the region recognized by Efb and contains a putative binding site for the platelet integrin GPIIb/IIIa receptor complex involved in platelet aggregation.

Bacterial Proteins↗
PubMed2001

Epstein-Barr virus in gastric carcinoma is associated with location in the cardia and with a diffuse histology: a study in one area of Chile.

Epstein-Barr virus (EBV) has been associated with the most common form of stomach neoplasms, the gastric carcinoma (GC). The presence of EBV-encoded small RNAtype-1 (EBER-1), a marker for EBV infection was analyzed by in situ hybridization (ISH) in 185 formalin-fixed and paraffin-embedded cases of GC from a high risk region. We found 31 (16.8%) EBV-positive cases with no relationship to age. Although male predominance (19% in males and 12.5% in females) was observed, the gender difference did not achieve statistical significance. Odds ratio (OR) for cardia location was 5.4 (95% CI 1.7-17.3) when antrum was used as referent category and the effects of gender and age were taken into account. The proportion of EBV-positive cases in diffuse histology was higher than intestinal type (OR = 4.8, 95% CI = 2.0-11.1). Our findings are contrary to a previously accepted hypothesis, that high-risk countries for GC have low rates of EBV-associated GC. In addition, our findings regarding location, histology and weak male predominance are different from what has been described in Asian and European countries, but similar to those described in Mexico and Mexican descendants living in the U.S. suggesting unique characteristics of EBV-associated GC in Latin-America.

Adult↗
PubMed2001

Gastric permeability is not increased in children colonized by CagA-positive strains of Helicobacter pylori.

BACKGROUND: Sucrose permeability has been used as a marker to detect gastric lesions in children. As CagA status of Helicobacter pylori is an important factor in determining the evolution of the gastric lesion, CagA-positive strains being more frequently associated with severe mucosal lesions, the aim of this study was to determine the prevalence of CagA-positive strains in Helicobacter pylori-colonized children and to evaluate whether the sucrose permeability test might discriminate between colonization by CagA-positive or negative strains. PATIENTS AND METHODS: A series of 38 children (11.1+/-3.6 years) who required upper endoscopy for diagnostic purposes were included in the study. Endoscopy was carried out after the sucrose permeability test, and gastric biopsies were obtained for histologic examination, Helicobacter pylori detection by Giemsa staining and CLO-test, and determination of CagA status of the colonizing Helicobacter pylori strains by polymerase chain reaction. RESULTS: Helicobacter pylori was detected in 26 subjects (68.4%) and of these, 16 (61.5%) were colonized by CagA-positive strains. The intensity of the histologic findings was significantly associated with the presence of Helicobacter pylori and with CagA status of the infecting strains (chi2=21.2, p=0.0017). However no significant difference in the urinary excretion of sucrose between children not colonized and children with CagA- negative or positive strains was observed (0.027% [0.012-0.035%]; 0.027% [0.016-0.047%] and 0.026% [0.016-0.038], median [range], respectively; Kruskal-Wallis analysis of variance F=0.75, p=0.69). CONCLUSIONS: These results indicate that in Chile, about 60% of the Helicobacter pylori infected children are colonized by CagA-positive strains, in association with more intense lesions of the gastric mucosa, but that gastric permeability to sucrose does not discriminate between colonization by CagA-negative and positive strains of Helicobacter pylori.

Abdominal Pain↗
PubMed2001

Supercritical fluid extraction of 5-hydroxymethyl-2-furaldehyde from raisins.

An extraction method based on supercritical CO(2) has been developed for the analysis of 5-hydroxymethyl-2-furaldehyde in raisins. To optimize extraction variables, a fractional factorial experimental design was applied. Six extraction variables were optimized. The organic modifier used for increasing the extraction fluid solvating power was the most important factor. Methanol as organic modifier produced 10-fold higher recoveries of 5-hydroxymethyl-2-furaldehyde than ethyl acetate. The efficiency of the organic modifier in the static extraction phase was compared with using it in the dynamic extraction phase. Repeatability of the analysis method was evaluated, which resulted in an RSD of <5%. 5-Hydroxymethyl-2-furaldehyde was quantified in raisins, and the concentration was found to be 0.128 mg/g of raisin.

Carbon Dioxide↗
PubMed2001

Evaluation of a tetracycline-inducible promoter in Staphylococcus aureus in vitro and in vivo and its application in demonstrating the role of sigB in microcolony formation.

An inducible promoter system provides a powerful tool for studying the genetic basis for virulence. A variety of inducible systems have been used in other organisms, including pXyl-xylR-inducible promoter, the pSpac-lacI system, and the arabinose-inducible P(BAD) promoter, but each of these systems has limitations in its application to Staphylococcus aureus. In this study, we demonstrated the efficacy of a tetracycline-inducible promoter system in inducing gene expression in S. aureus in vitro and inside epithelial cells as well as in an animal model of infection. Using the xyl/tetO promoter::gfp(uvr) fusion carried on a shuttle plasmid, we demonstrated that dose-dependent tetracycline induction, as measured by bacterial fluorescence, occurred in each of the above environments while basal activation under noninduced conditions remained low. To ascertain how the system can be used to elucidate the genetic basis of a pathogenic phenotype, we cloned the sigB gene downstream of the inducible promoter. Induction of SigB expression led to dose-dependent attachment of the tested strain to polystyrene microtiter wells. Additionally, bacterial microcolony formation, an event preceding mature biofilm formation, also increased with tetracycline induction of SigB.

Animals↗
PubMed2001

sigma(B) activity in Staphylococcus aureus is controlled by RsbU and an additional factor(s) during bacterial growth.

Two genes of the sigB operon, rsbU and rsbV, were deleted in an rsbU(+) strain (FDA486) to evaluate the contribution of these two genes to sigma(B) activity in Staphylococcus aureus. The sigma(B) protein level and the transcription of two sigma(B)-dependent promoters (sigB and sarA P3 transcripts) were analyzed in the constructed mutants. A deletion of the first gene (rsbU) within the sigB operon led only to a partial reduction in sigma(beta) activity. A deletion of the second gene (rsbV) resulted in a more dramatic reduction in the sigma(B) protein level and its activity than did the deletion of rsbU, thus indicating that RsbV can be activated independent of RsbU. In the parental strain, the sigma(B)-dependent transcript initiated upstream of rsbV was 28-fold higher than the sigma(A)-dependent transcript originating from the rsbU promoter. The level of the sigma(B)-dependent transcript decreased up to 50% in the rsbU mutant and up to 90% in the rsbV mutant compared with the transcript in the wild type. The yellow pigment of S. aureus colonies, a sigma(B)-dependent phenotype, was partially reduced in the rsbU and rsbV mutants, whereas alpha-hemolysin was increased. Additionally, the sarA P3 promoter activity of the parental strain was induced to a higher level in response to pH 5.5 than was that of the rsbU or rsbV mutant, indicating that RsbU is the major activator of the sigma(B) response to acid stress. Using a tetracycline-inducible system to modulate the expression of RsbW, we progressively repressed pigment production, presumably by reducing the free sigma(B) level. Collectively, our data indicated that RsbU and RsbV in S. aureus contributed to different levels of sigma(B) protein expression and varying sigma(B) activities. Although RsbV can activate sigma(B) independent of RsbU, RsbU remains the major activator of sigma(B) during acid stress.

Bacterial Proteins↗
PubMed2001

[Helicobacter pylori: cagA analysis and vacA genotyping in Chile. Detection of a s2/m1 strain].

BACKGROUND: The genes cagA and vacA encode H pylori virulence factors. AIM: To genotype these genes in H pylori strains isolated from patients with upper gastrointestinal symptoms. MATERIAL AND METHODS: We studied 50 patients who underwent an upper gastrointestinal endoscopy, with positive culture for H pylori. Detection of cagA and vacA genotyping was done using polymerase chain reactions. RESULTS: The gene cagA was detected in 19 samples (38%). Signal sequences s1 and s2 of vacA gene were detected in 16 samples each (32%). There was simultaneous amplification of s1 and s2 in 6 samples and they were not detected in 9 samples. The middle region of vacA was m1 in 9 samples, m2 in 29 samples and there was simultaneous amplification of m1 and m2 in 12 samples. In 16 samples (32%), more than one type of signal sequence or medial region was detected. Of those patients in whom vacA was the only genotype detected, 15 were s2/m2, 7 were s1/m1, 4 were s1/m2 and 1 was s2/m1. CONCLUSIONS: In these patients, the infection with cagA- H pylori strains, predominates, the prevalence of infection with s1 or s2 strains is similar and the predominant medial region is m2.

Antigens, Bacterial↗
PubMed2000

Supercritical fluid extraction of grape glycosides.

Supercritical fluid extraction with methanol-modified CO(2) was used to extract glycosides from grapes. An optimization design involving 12 extraction variables was applied to achieve quantitative recoveries. The most important factor was the amount of organic modifier, a consequence of the high degree of glycoside polarity. By the proposed method, the total time of analysis can be decreased relative to that required for more conventional extractions. The full method can also be automated.

Carbon Dioxide↗
PubMed2000

Antibody responses in patients with staphylococcal septicemia against two Staphylococcus aureus fibrinogen binding proteins: clumping factor and an extracellular fibrinogen binding protein.

We analyzed the serum antibody responses against two Staphylococcus aureus fibrinogen binding proteins, the cell-bound clumping factor (Clf) and an extracellular fibrinogen binding protein (Efb). The material consisted of 105 consecutive serum samples from 41 patients suffering from S. aureus septicemia and 72 serum samples from healthy individuals. An enzyme-linked immunosorbent assay (ELISA) was developed. Healthy individuals showed variable levels of antibodies against the studied antigens, and cutoff levels (upper 95th percentile) against these antigens were determined. No correlation was seen between serum antibody levels against Clf and Efb. In acute-phase samples 27% of patients showed positive antibody levels against Clf and 10% showed positive levels against Efb, while in convalescent-phase samples 63% (26 of 41) showed a positive serology against Clf and 49% (20 of 41) showed a positive serology against Efb. Antibody levels against Efb were significantly lower in the acute-phase sera than in sera from healthy individuals (P = 0. 002). An antibody response against Clf was most frequent in patients suffering from osteitis plus septic arthritis and from endocarditis (80% positive). The antibody response against Efb appeared to develop later in the course of disease. A possible biological effect of measured antibodies was demonstrated with the help of an inhibition ELISA, in which both high-titer and low-titer sera inhibited the binding of bacteria to fibrinogen. In conclusion, we have demonstrated in vivo production of S. aureus fibrinogen binding proteins during deep S. aureus infections and a possible diagnostic and prophylactic role of the corresponding serum antibodies in such infections.

Adolescent↗
PubMed1999

Extraction of polyphenolic compounds from grape seeds with near critical carbon dioxide.

A new analytical method using near critical carbon dioxide to extract polyphenolic compounds from white grape seeds has been developed. Carbon dioxide density, organic modifier, percentage of modifier, and extraction temperature were optimized utilizing an experimental design. Gallic acid, catechin, and epicatechin were the main phenolic compounds detected in the HPLC chromatogram of each extract. Recovery and reproducibility of catechin from grape seed was calculated. Under optimized conditions recovery was estimated to be 79% with a RSD equal to 7.3%. Results from the supercritical fluid method were compared with results obtained via liquid-solid extraction using methanol-water.

Carbon Dioxide↗