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Biomedical subjects

A Segura

Publications and source records attributed to A Segura.

At least 55 records · Page 3Linked to original sources
PubMed1999

Long-term results after combined modality treatment for non-metastatic osteosarcoma.

Since the introduction of multimodality treatment, the prognosis of patients with high-grade non-metastatic osteosarcoma has significantly improved. A retrospective review was performed to assess the long-term results of this approach in a single centre setting, and to investigate the impact of potential clinical prognostic factors. Between 1985 and 1993, 35 patients with stage II-A and II-B osteosarcoma underwent preoperative chemotherapy (high-dose methotrexate), wide surgery, and adjuvant chemotherapy (cisplatin-doxorubicin/bleo-mycin-cyclophosphamide-dactinomycin) (modified T-10A protocol). There were 19 males and 16 females. Median patient age was 17 y (range 12-42). Primary tumour sites were the extremities (83%) and axial bones (17%). In spite of an unfavourable grade 3-4 histologic response rate to high-dose methotrexate of 12%, 31 (88%) patients were able to undergo limb-sparing surgery and 28 (80%) were rendered disease free after the planned therapy. Median follow-up was 8 y. The actuarial overall survival and disease-free survival rates were 64% and 49% at 5 y, and 59% and 49% at 10 y, respectively. Tumour size and primary site were significant prognostic factors for survival in univariate analyses. In conclusion, long-term survival after combined modality treatment can be achieved in more than 60% of patients with localised osteosarcoma, including non-appendicular lesions. Limb-sparing surgery is a realistic goal for most cases. The prognostic value of tumour necrosis and the efficacy of neoadjuvant chemotherapy should be interpreted according to individual high-dose methotrexate scheduling.

Adolescent↗
PubMed1999

ESHAP is an active regimen for relapsing Hodgkin's disease.

BACKGROUND: Refractory or relapsing Hodgkin's disease is associated with a poor prognosis. There is no widely accepted salvage chemotherapy regimen for these patients. However, the addition of high-dose chemotherapy followed by autologous hematopoietic transplantation (AHT) has proven of benefit to them. A prospective clinical trial was carried out to evaluate the efficacy and toxicity of ESHAP (etoposide, methylprednisolone, high-dose cytarabine, and cisplatin). PATIENTS AND METHODS: Twenty-two patients with refractory (5) or relapsing Hodgkin's disease (17) were entered and scheduled to receive three courses of ESHAP. Patients suitable for AHT were then given high-dose chemotherapy with CBV (cyclophosphamide, carmustine, and etoposide) plus AHT, whereas responding, non-AHT-suitable patients completed six ESHAP courses. RESULTS: Nine patients achieved complete responses and seven partial responses (overall response rate 73%) with ESHAP. Grade 3-4 myelotoxicity was seen in 13 patients (59%). Nine patients received CBV plus AHT. At a median follow-up time of 50 months (range 6-96), seven patients (32%) are alive and disease-free. Three patients died of toxic effects of ESHAP (1) or CBV (2). Actuarial overall survival and disease-free survival were 35% and 27% at three years. CONCLUSIONS: ESHAP is an active regimen for relapsing Hodgkin's disease, with myelosuppression as its dose-limiting toxicity. An increased risk of treatment-related mortality when it is combined with high-dose chemotherapy can not be ruled out.

Adolescent↗
PubMed1999

Fracture resistance of four different restorations for cuspal replacement.

The purpose of this study was to compare the fracture resistance of four posterior restorations involving an entire cusp replacement. Four groups were established, each containing eight caries-free mandibular molars, similar in size and anatomic form. A mesio-occlusal preparation including the lingual cusp was prepared on all teeth. Group A were restored with a pin-retained amalgam. Group B were restored with amalgam and a meta adhesive. Group C were restored with a composite resin with a beta-glass quartz insert. Group D were restored with composite resin and a HEMA adhesive. All specimens were mounted in acrylic and stored in artificial saliva for 30 days. Each specimen was loaded in compression at a 90 degrees angle in an Instron testing machine with a crosshead speed of 0.5 cm/min. Results demonstrated the mean (SD) failure loads in kilograms for each group to be: A, 1155 (388); B, 1232 (436); C, 1345 (375); D, 1595 (373). Analysis of variance indicated no significant difference among groups at P<0.05. Although the values for the composite resin restoration with the adhesive were higher than the other restorative techniques.

Adhesives↗
PubMed1999

Gender differences in children's hospitalization in Catalonia: another inequality?

The aim of this study was to describe children's hospitalization and to analyse gender differences by selected diagnostic and procedure groups. Using the Clinical Classification for Health Policy Research Version 2 (CCHPR), 81 888 hospitalizations from the Minimum Basic Data Set of Hospital Discharge (CMBDAH) of 1995 related to children under 15 y of age in Catalonia, Spain, were studied. Hospitalization rates, number of days in hospital, average length of stay (d) in hospital and the standardized hospitalization ratio (SHR) (hospitalization rate in boys/hospitalization rate in girls) were computed. Two independent approaches were taken: (i) gender-specific categories were excluded in order to compare hospitalizations by sex; (ii) a selected group of 17 diagnostic and procedure categories were chosen in order to carry out the specific gender comparison. In both approaches, the selected indicators were compared by age groups, and totals were standardized by age using the direct method. An excess of hospitalization in boys was observed (SHR = 1.18; 95% CI: 1.17-1.19). The number of days spent in hospital and hospitalization rates were higher in infants and were also higher for boys than for girls. The average length of stay in hospital was higher in infants and in girls at all ages. These differences were systematic when stratified by health region, admission and discharge circumstances and hospital category. Except for urinary infection, which was higher in girls (SHR: 0.65; CI 95%: 0.54-0.76), the SHR was higher in boys in all diagnostic and procedure categories analysed (all SHR >1). Specific sex categories, injuries and poisonings cannot on their own explain a higher level of hospitalization among boys. More specific studies are needed to explain the role of the family and the healthcare system in gender inequalities in children's hospitalization.

Adolescent↗
PubMed1999

Snakin-1, a peptide from potato that is active against plant pathogens.

A new type of antimicrobial peptide, snakin-1 (SN1), has been isolated from potato tubers and found to be active, at concentrations < 10 microM, against bacterial and fungal pathogens from potato and other plant species. The action of SN1 and potato defensin PTH1 was synergistic against the bacterium Clavibacter michiganensis subsp. sepedonicus and additive against the fungus Botrytis cinerea. Snakin-1 causes aggregation of both gram-positive and gram-negative bacteria. The peptide has 63 amino acid residues (M(r) 6,922), 12 of which are cysteines, and is unrelated to any previously isolated protein, although it is homologous to amino acid sequences deduced from cloned cDNAs that encode gibberellin-inducible mRNAs and has some sequence motifs in common with kistrin and other hemotoxic snake venoms. A degenerate oligonucleotide probe based on the internal sequence CCEECKC has been used to clone an SN1 cDNA. With the cDNA used as probe, one copy of the StSN1 gene per haploid genome has been estimated and expression of the gene has been detected in tubers, stems, axillary buds, and young floral buds. Expression levels in petals and carpels from fully developed flowers were much higher than in sepals and stamens. The expression pattern of gene StSN1 suggests that protein SN1 may be a component of constitutive defense barriers, especially those of storage and reproductive plant organs.

Amino Acid Sequence↗
PubMed1999

Genetic analysis of a chromosomal region containing vanA and vanB, genes required for conversion of either ferulate or vanillate to protocatechuate in Acinetobacter.

VanA and VanB form an oxygenative demethylase that converts vanillate to protocatechuate in microorganisms. Ferulate, an abundant phytochemical, had been shown to be metabolized through a vanillate intermediate in several Pseudomonas isolates, and biochemical evidence had indicated that vanillate also is an intermediate in ferulate catabolism by Acinetobacter. Genetic evidence supporting this conclusion was obtained by characterization of mutant Acinetobacter strains blocked in catabolism of both ferulate and vanillate. Cloned Acinetobacter vanA and vanB were shown to be members of a chromosomal segment remote from a supraoperonic cluster containing other genes required for completion of the catabolism of ferulate and its structural analogs, caffeate and coumarate, through protocatechuate. The nucleotide sequence of DNA containing vanA and vanB demonstrated the presence of genes that, on the basis of nucleotide sequence similarity, appeared to be associated with transport of aromatic compounds, metabolism of such compounds, or iron scavenging. Spontaneous deletion of 100 kb of DNA containing this segment does not impede the growth of cells with simple carbon sources other than vanillate or ferulate. Additional spontaneous mutations blocking vanA and vanB expression were shown to be mediated by IS1236, including insertion of the newly discovered composite transposon Tn5613. On the whole, vanA and vanB appear to be located within a nonessential genetic region that exhibits considerable genetic malleability in Acinetobacter. The overall organization of genes neighboring Acinetobacter vanA and vanB, including a putative transcriptional regulatory gene that is convergently transcribed and overlaps vanB, is conserved in Pseudomonas aeruginosa but has undergone radical rearrangement in other Pseudomonas species.

Acinetobacter↗
PubMed1999

The physiological contribution of Acinetobacter PcaK, a transport system that acts upon protocatechuate, can be masked by the overlapping specificity of VanK.

VanK is the fourth member of the ubiquitous major facilitator superfamily of transport proteins to be identified that, together with PcaK, BenK, and MucK, contributes to aromatic catabolism in Acinetobacter sp. strain ADP1. VanK and PcaK have overlapping specificity for p-hydroxybenzoate and, most clearly, for protocatechuate: inactivation of both proteins severely impairs growth with protocatechuate, and the activity of either protein alone can mask the phenotype associated with inactivation of its homolog. Furthermore, vanK pcaK double-knockout mutants appear completely unable to grow in liquid culture with the hydroaromatic compound quinate, although such cells on plates convert quinate to protocatechuate, which then accumulates extracellularly and is readily visible as purple staining. This provides genetic evidence that quinate is converted to protocatechuate in the periplasm and is in line with the early argument that quinate catabolism should be physically separated from aromatic amino acid biosynthesis in the cytoplasm so as to avoid potential competition for intermediates common to both pathways. Previous studies of aromatic catabolism in Acinetobacter have taken advantage of the ability to select directly strains that contain a spontaneous mutation blocking the beta-ketoadipate pathway and preventing the toxic accumulation of carboxymuconate. By using this procedure, strains with a mutation in structural or regulatory genes blocking degradation of vanillate, p-hydroxybenzoate, or protocatechuate were selected. In this study, the overlapping specificity of the VanK and PcaK permeases was exploited to directly select strains with a mutation in either vanK or pcaK. Spontaneous mutations identified in vanK include a hot spot for frameshift mutation due to contraction of a G6 mononucleotide repeat as well as point mutations producing amino acid substitutions useful for analysis of VanK structure and function. Preliminary second-site suppression analysis using transformation-facilitated PCR mutagenesis in one VanK mutant gave results similar to those using LacY, the prototypic member of the major facilitator superfamily, consistent with the two proteins having a similar mechanism of action. The selection for transport mutants described here for Acinetobacter may also be applicable to Pseudomonas putida, where the PcaK permease has an additional role in chemotaxis.

Acinetobacter↗
PubMed1999

Influence of proxy respondents in children's health interview surveys.

STUDY OBJECTIVES: To study the influence of the proxy respondent on health interview surveys in children. DESIGN: Cross sectional study. SETTING: Children under the age of 15 years drawn from the general population of Catalonia, Spain. PARTICIPANTS: The Catalan Health Interview Survey consisted of a multistage probability sample representative to the population of Catalonia. The sample size was 2433 children younger than 15 years of age. The interviews were answered by proxy respondents (the mother, father, or other carer), with the questionnaire adapted for the proxy respondent. Logistic regression models were used to analyse the relation between the proxy respondent's characteristics and health status and health care utilisation, controlling for the effect of sociodemographic factors. MAIN RESULTS: Proxy respondent's characteristics influenced the reports of chronic conditions and accidents within the last year. Proxy respondents over 55 years (OR = 0.47; 95% CI = 0.26, 0.82), men (OR = 0.69; 95% CI = 0.53, 0.89), the father (OR = 0.66; 95% CI = 0.50, 0.89), and the grandparents (OR = 0.49; 95% CI = 0.26, 0.89), reported a lower rate of chronic conditions. Age of the proxy 55 years or greater (OR = 0.41; 95% CI = 0.20, 0.82), men (OR = 0.70; 95% CI = 0.52, 0.94), fathers (OR = 0.68; 95% CI = 0.49, 0.92), and grandparents (OR = 0.40; 95% CI = 0.18, 0.85) showed a lower probability to report accidents. No variables related to the proxy were associated with physician visits or hospitalisation in the previous year. CONCLUSIONS: Selected characteristics of the proxy respondent can influence responses to health surveys involving children. A minimum set of basic data should be collected from the proxy respondent to evaluate different patterns of response.

Adolescent↗
PubMed1999

Gender inequalities in health and health care services use in Catalonia (Spain).

BACKGROUND AND OBJECTIVES: While socio-economically derived differences in health and health services use have long been a subject of study, differences based on gender, considered as the explicative variable, have scarcely been quantified from population-based data. The aim of this investigation was to analyse inequalities in health and health care services utilisation between men and women in Catalonia (Spain). DESIGN, SETTING, PARTICIPANTS, AND MEASURES: Data from the Catalan Health Interview Survey, a cross sectional survey conducted in 1994, were used. A total of 6604 women and 5641 men aged 15 years or over were included for analysis. Health related variables studied were self perceived health, restriction of activity (past two weeks), and presence of chronic conditions; health services use variables analysed were having visited a health professional (past two weeks), an optometrist (12 months), or a dentist (12 months); and hospitalisation (past 12 months). Age standardised proportions were computed according to gender, and prevalence odds ratios (OR) were derived from logistic regression equations. MAIN RESULTS: Women more frequently rated their health as fair or poor than men (29.8% v 21.4%; OR = 1.22; 95% CI: 1.10, 1.34). More women than men reported having restricted activity days (OR = 1.86; 95% CI: 1.59, 2.18) and chronic conditions (OR = 1.74; 95% CI: 1.60, 1.89). The proportion of women visiting a health professional was slightly greater than that for men (OR = 1.20; 95% CI: 1.09, 1.31), as was the proportion of women visiting an optometrist (OR = 1.21; 95% CI: 1.11, 1.33), and a dentist (OR = 1.43; 95% CI: 1.31, 1.55). The proportion of hospitalisation was lower in women (6.6%) than in men (7.7%; OR = 0.73; 95% CI: 0.63, 0.85). When health services use was analysed according to self perceived health, women declaring good health reported a greater probability of consulting a health professional (OR = 1.35; 95% CI: 1.20, 1.52). There were no differences in respect to hospitalisation, visits to the optometrist and to the dentist. CONCLUSIONS: These results indicate a pattern close to the inverse care law, as women, who express a lower level of health and thus would need more health care, are not, however, using health services more frequently than men.

Adolescent↗
PubMed1999

Clinical performance and caries inhibition of resin-modified glass ionomer cement and amalgam restorations.

BACKGROUND: The authors clinically examined two restorative materials to evaluate their effectiveness in Class II restorations in primary molars and their ability to inhibit recurrent caries. METHODS: Forty subjects, each in need of two Class II restorations in primary molars, took part in this study. Each patient received one Class II restoration of resin-modified glass ionomer cement and one of amalgam. The authors evaluated the restorations at six-month, one-year, two-year and three-year recall appointments. On exfoliation, teeth with experimental restorations were retrieved and microscopically examined for inhibition of demineralization at restoration margins. RESULTS: The results of the clinical evaluation demonstrated no significant differences between the resin-modified glass ionomer cement restorations and the amalgam restorations (P < .05). Polarized light microscopic examination of the returned teeth that were restored as a part of this study indicated that the resin-modified glass ionomer cement had significantly less enamel demineralization at restoration margins than did amalgam (P < .0001). CONCLUSIONS: The resin-modified glass ionomer cement functioned clinically as well as amalgam for Class II restorations in primary molars. However, the resin-modified glass ionomer exhibited significantly less enamel demineralization at restoration margins than did amalgam. CLINICAL IMPLICATIONS: Resin-modified glass ionomer cement restorative material functions well for Class II restorations in primary molars and exhibits less recurrent caries at restoration margins than does amalgam.

Cariostatic Agents↗
PubMed1999

Evaluating the effects of fluoride-releasing dental materials on adjacent interproximal caries.

BACKGROUND: The authors examined several restorative materials to evaluate their ability to inhibit demineralization and enhance remineralization of incipient carious lesions on the interproximal enamel of teeth adjacent to those restored with the materials. METHODS: Twenty-one subjects in need of a crown on a mandibular molar and a Class II inlay on an adjacent tooth took part in this six-phase study. Artificial enamel lesions were created and positioned within the interproximal portion of a crown. Lesions were photographed with polarized light microscopy and characterized before and after 30-day intraoral exposures. Each phase included the placement of a new section in the crown model and a new Class II inlay restorative material in the adjacent tooth. RESULTS: Results demonstrated that nonfluoridated resin composite, fluoridated resin composite and resin-modified glass ionomer restorative materials, when placed in subjects who brushed with a fluoridated dentifrice, demonstrated significantly (P < .05) less enamel demineralization than the nonfluoridated resin composite control placed in subjects who brushed with a nonfluoridated dentifrice. The resin-modified glass ionomer cement, however, even when brushed with a nonfluoridated dentifrice, exhibited significantly (P < .05) less demineralization than the nonfluoridated resin composite control brushed with a nonfluoridated dentifrice. CONCLUSIONS: Resin-modified glass ionomer cement appears to significantly inhibit demineralization of interproximal enamel of teeth adjacent to those restored with the material. CLINICAL IMPLICATIONS: Resin-modified glass ionomer cement restorations can enhance prevention of enamel demineralization on adjacent teeth.

Acrylic Resins↗
PubMed1999

[The Spanish version of EuroQol: a description and its applications. European Quality of Life scale].

BACKGROUND: To introduce the EuroQol 5D (EQ-5D) to health care professionals wishing to use it as a measure of health-related quality of life. METHODS: This paper is based on a review of studies using the EQ-5D in Spanish populations which include chronic and critical patients, health care users, and random samples of the general population in Navarra and Catalonia. RESULTS: Results are presented for three aspects of the EQ-5D: the descriptive system, the visual analogic scale, and the EQ-5D tariff. Presence of problems on the descriptive system and lower scores on the visual analogue scale were positively associated with increasing age, being female, lower educational level and social class, presence of chronic conditions, higher levels of restricted activity, visits to a health care professional in the previous 15 days, and hospitalisation during the previous year. The ability of the descriptive system and the visual analogic scale to discriminate between healthy individuals and critical and chronic patients was good. Social tariffs for EQ-5D health states have been obtained based on self-rated health and the rating of hypothetical health states (health states not experienced by the rater). Tariffs for hypothetical health states have been obtained using visual analogic scale and time trade-off techniques. Tariffs also discriminate between healthy and non-healthy subjects, and are a valid reflection of preferences for health states. CONCLUSIONS: The Spanish version of the EQ-5D is a simple, valid and practical measure for its use as an outcome variable both in clinical research and in the allocation of health care resources:

Europe↗
PubMed1999

Evaluation of the in vitro Activity of Two Fourth-Generation Cephalosporins Against Bacterial Samples Isolated From Patients in Several Brazilian Hospitals.

Cefpirome and cefepime are two fourth-generation cephalosporins recently introduced in Brazil. They have a very similar range of in vitro antimicrobial activity, but some differences have been noticed. The goal of this study was to compare the in vitro activity of cefpirome and cefepime against bacterial samples isolated in Brazilian hospitals. We studied 931 samples taken from hospitalized patients between April and June, 1998. The minimum inhibitory concentration (MIC) was determined by the Etest method. The potency of cefpirome was similar to that of cefepime, except against enterococci and coagulase-negative staphylococci, where cefpirome proved 2-fold more potent. The MIC(90) for cefepime were inferior to cefpirome in response to Klebsiella pneumoniae (MIC(90), 24 and 96µg/mL, respectively), Pseudomonas aeruginosa (MIC(90), 48 and 128µg/mL, respectively), and other Gram-negative organisms (MIC(90), 64 and 256µg/mL, respectively). Despite the fact that cefpirome presented a slightly broader range of action against Gram-positive bacteria (90% sensitive vs. 78% sensitive to cefepime), and that cefepime presented an equally broad range against Gram-negative bacteria (74% sensitive vs. 65% sensitive to cefpirome), these differences were not considered clinically significant because the sensitivity differed in MIC by less than 2 dilutions. Only 16 (1.7%) of the 931 samples tested showed a significant difference in sensitivity. This study suggests that, except for Acinetobacter sp. and P. aeruginosa, laboratories may routinely test only cefpirome and apply the same category result to cefepime. Since category discrepancies are very rare and cefpirome is slightly less active than cefepime against Enterobacteriaceae, isolates susceptible to cefepime will certanly also be susceptible to cefpirome. To optimize the treatment of severely infected patients, especially where species such as Acinetobacter sp and P. aeruginosa are involved, we recommend that both cephalosporins be tested by using the same susceptibility test method to determine the MIC.

Journal Article↗
PubMed1998

Novel defensin subfamily from spinach (Spinacia oleracea).

Antimicrobial peptides (So-D1-7) were isolated from a crude cell wall preparation from spinach leaves (Spinacia oleracea cv. Matador) and, judged from their amino acid sequences, six of them (So-D2-7) represented a novel structural subfamily of plant defensins (group IV). Group-IV defensins were also functionally distinct from those of groups I-III. They were active at concentrations < 20 microM against Gram-positive (Clavibacter michiganensis) and Gram-negative (Ralstonia solanacearum) bacterial pathogens, as well as against fungi, such as Fusarium culmorum, F. solani, Bipolaris maydis, and Colletotrichum lagenarium. Fungal inhibition occurred without hyphal branching. Group-IV defensins were preferentially distributed in the epidermal cell layer of leaves and in the subepidermal region of stems.

Amino Acid Sequence↗