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Biomedical subjects

J Fernández-Crehuet

Publications and source records attributed to J Fernández-Crehuet.

16 recordsLinked to original sources
PubMed2004

Assessing the residual antibacterial activity of clinical materials disinfected with glutaraldehyde, o-phthalaldehyde, hydrogen peroxide or 2-bromo-2-nitro-1,3-propanediol by means of a bacterial toxicity assay.

This study investigated the use of a rapid bacterial toxicity test for detecting disinfectant residues released by disinfected materials. The test substances included an environmental disinfectant used in hospitals in high-risk areas, such as critical care units or emergency services, and three disinfectants used on clinical devices when a high level of disinfection is required. The test materials were polyurethane, polypropylene, glass, latex and cotton from different instruments and utensils used in hospitals. Of the four test disinfectants, o-phthalaldehyde (OPA) and 2-bromo-2-nitro-1,3-propanediol (BNP) showed the greatest inhibitory activity (as much as 300-fold greater than hydrogen peroxide in the case of OPA) according to the toxicity text. However, with the exception of hydrogen peroxide on latex, it was the most porous test materials, namely latex and cotton, that accumulated the least residue. BNP was the disinfectant that left the least residue on the five test materials, while the greatest residual concentration was left by hydrogen peroxide on latex (as much as 5 microg/cm2). The biotest used in this study permitted the detection of disinfectant residues released by different types of previously disinfected clinical materials, and can be adapted to simulate elution conditions similar to those existing in routine hospital practice.

Biological Assay↗
PubMed2001

Methodological quality and reporting of ethical requirements in clinical trials.

OBJECTIVES: To assess the relationship between the approval of trials by a research ethics committee (REC) and the fact that informed consent from participants (ICP) was obtained, with the quality of study design and methods. DESIGN: Systematic review using a standardised checklist. MAIN MEASURES: Methodological and ethical issues of all trials published between 1993 and 1995 in the New England Journal of Medicine, the Lancet, the Journal of the American Medical Association and the British Medical Journal were studied. In addition, clinical trials conducted in Spain and published by at least one Spanish author during the same period in any other journal were also included. RESULTS: We studied the published articles of 767 trials and found the following indicators of lower methodological quality to be independent predictors for failure to disclose REC approval or ICP: absence of concealment of allocation, lack of justification for unblinded trials, not using a treatment for the patients in the control group, absent information on statistical methods, not including sample size estimation, not establishing the rules to stop the trial, and omitting the presentation of a baseline comparison of groups. CONCLUSION: Trials of higher methodological and scientific quality were more likely to provide information about their ethical aspects.

Bibliometrics↗
PubMed1999

Development and testing of a microbiological assay to detect residual effects of disinfectant on hard surfaces.

We describe a glucuronidase bioassay for detecting residual bactericidal activity from the use of disinfectants on hard surfaces; in this assay we used formaldehyde, ethanol, isopropanol, chlorine, and a commercial preparation containing 2-bromo-2-nitro-1, 3-propanediol. Chlorine and the commercial preparation showed bactericidal activity (53.5% and 98.2%, respectively) for a week after disinfection.

2-Propanol↗
PubMed1999

Flexible flat feet in children: a real problem?

OBJECTIVES: To estimate the prevalence of flexible flat feet in the provincial population of 4- to 13-year-old schoolchildren and the incidence of treatments considered unnecessary. SETTING: Province of Málaga, Spain. METHODS: We examined and graded by severity a sample of 1181 pupils taken from a total population of 198 858 primary schoolchildren (CI: 95%; margin of error: 5%). The sample group was separated into three 2-year age groups: 4 and 5 years, 8 and 9 years, and 12 and 13 years. The plantar footprint was classified according to Denis1 into three grades of flat feet: grade 1 in which support of the lateral edge of the foot is half that of the metatarsal support; grade 2 in which the support of the central zone and forefoot are equal; and grade 3 in which the support in the central zone of the foot is greater than the width of the metatarsal support. The statistical analysis for the evaluation of the differences between the groups was performed with Student's t and chi2 tests as appropriate. RESULTS: The prevalence of flat feet was 2.7%. Of the 1181 children sampled, 168 children (14.2%) were receiving orthopedic treatment, but only 2.7% had diagnostic criteria of flat feet. When we inspected the sample, we found that a number of children were being treated for flat feet with boots and arch supports. Most of them did not have a flat plantar footprint according to the criteria that we used for this work. Furthermore, in the group of children that we diagnosed as having flat feet, only 28.1% were being treated. We found no significant differences between the number of children receiving orthopedic treatments and the presence or absence of a flat plantar footprint. Children who were overweight in the 4- and 5-year-old group showed an increased prevalence for flat feet as diagnosed by us. CONCLUSION: The data suggest that an excessive number of orthopedic treatments had been prescribed in the province. When extrapolated to the 1997 population of schoolchildren within the age groups studied the figures suggested that approximately 28 167 children in Málaga province probably would have been receiving orthopedic treatments with boots and insoles at the time of our study. Consequently, the total expenditure on orthopedic boots and insoles that year could be estimated as 676 008 000 pesetas ($4 447 422 in US currency).

Adolescent↗
PubMed1998

Interference by carbohydrate substrates, flavonoids, and monosaccharide derivatives on bacterial beta-D-glucuronidase assays.

Most commercially available test kits for water and foodstuffs use beta-galactosidase activity for coliforms and beta-glucuronidase activity for Escherichia coli. We tested the effects on the beta-glucuronidase activity of E. coli W3110 of substances usually present in foods and several synthetic pharmaceutical compounds. Thirteen substances were tested: three carbohydrates, four flavonoids, five monosaccharide derivatives, and dimethyl sulphoxide. In a minimum medium without any other carbon source, glucose (0.1 mM), quercetin (0.1 mM), silymarin (10 mg/L), D-gluconic acid (0.01 mM), D-gluconic acid lactone (0.01 mM), isopropyl-beta-D-thiogalacto pyranoside (1 mM), p-nitrophenyl beta-D-glucuronide (1 mM), and DMSO (1 M) completely inhibited E. coli glucuronidase activity at the above concentrations. However, the following compounds stimulated E. coli glucuronidase activity within the ranges of concentrations shown: glucose (0.0001-0.01 mM), lactose and sucrose (>0.1 mM), D-saccharic acid 1,4 lactone (0.0001-0.1 mM), p-nitrophenyl beta-D-glucuronide (0.001-0.01 mM) and DMSO (2-500 mM). In a rich culture medium that contained other carbon sources (lauryl tryptose broth) E. coli glucuronidase activity in the presence of the extra nutrients was unaffected by the test substances and therefore, under normal conditions in water or foods, they should not interfere with E. coli assays based on measurements of beta-glucuronidase activity.

Biological Assay↗
PubMed1997

Alcohol intake and risk of breast cancer: the euramic study.

To evaluate the association of alcohol intake with the risk of breast cancer in post-menopausal women, we analyzed the data from an international case-control study conducted in five European countries (FRG, Switzerland, Northern Ireland, the Netherlands and Spain). Information on alcohol intake was available in 315 cases and 364 controls. Medians for the tertiles of alcohol intake among current drinkers were 1.7, 6.0, and 20.0 g/day. Adjusted relative risks (and 95% confidence intervals) of breast cancer for each tertile of intake in current drinkers, compared to never drinkers, were 1.00 (0.60-1.67), 1.01 (0.60-1.73), and 1.18 (0.69-2.03). The adjusted relative risk for ex-drinkers was 1.73 (1.07-2.79). Among both current drinkers and ex-drinkers, the relative risk was higher for those with body mass index above the median compared to those with body mass index below the median. These results do not support a dose-response effect of alcohol on breast cancer risk, although consumption levels were too low to exclude increased risk with high regular intake. Further research is necessary to evaluate the risk of developing breast cancer among ex-drinkers and the potential interaction between body mass index and alcohol drinking.

Alcohol Drinking↗
PubMed1997

A trial to compare the effects of pH, buffer concentration, and NaCl, on one fluorescent and two bioluminescent bacterial tests for acute toxicity.

Of all the bioassays to determine acute toxicity described in the literature, those that employ bacteria as indicator organisms are usually the most rapid and the most economic, although alone they cannot predict the possible toxic effect of any type of substance. When bioassays are employed to test the toxicity of known substances and of compounds in samples from waste discharges they have to work in very different conditions from those for which they are designed. The effects of three factors, pH, buffer concentration, and NaCl, on the performance of a fluorogenic bioassay based on the beta-glucuronidase activity of Escherichia coli were investigated. The results of this test were compared with those of two known biluminescent bacteria tests. The fluorogenic bioassay has a more restricted optimum pH range, while the influence of buffer concentration was similar for the three tests. E. coli glucuronidase activity was affected at a concentration as low as 128 mg/l of NaCl. Changes in the pH or buffer concentrations or chloride ions, greatly influenced the respectives toxicities of four substances, acridine orange, TEMED, 2-mercaptoethanol, and mercuric chloride.

Acridine Orange↗
PubMed1994

New toxicity determination method that uses fluorescent assay of Escherichia coli.

We describe a new method that uses a fluorogenic bioassay of the beta-glucuronidase conversion of 4-methylumbelliferyl beta-D-glucuronide (MUG) to 4-methylumbelliferone to evaluate the individual toxic effects on Escherichia coli of Al3+, Cr6+, Hg2+ and Li+. This work was designed to examine the effectiveness of this method to measure the effects of five ionic concentrations of either Al3+, Cr6+, Hg2+ or Li+, on the growth of E. coli in a minimal medium that had MUG as the only source of carbon. This method was simple and fast, and its toxicity detection sensitivity was equal to, or greater than, existing bacterial bioassays. The use of the MUG substrate minimized the danger of interference by bacteria other than E. coli. Evaluations of toxicity in samples of public drinking water proved equally sensitive.

Aluminum↗
PubMedDate not supplied

Evaluation of the toxicity of several heavy metals by a fluorescent bacterial bioassay.

This new bioassay determined the toxicity of chemical compounds dissolved in water by measuring the degree of inhibition of the ultraviolet light-stimulated fluorescence of Escherichia coli in a culture medium in which 4-methylumbelliferyl beta-D-glucuronide was the only carbon source. Inhibition produced by one of five heavy-metal salts (Cd2+, Cr6+, Hg2+, Pb2+ or Zn2+) was the end-point and comparison standard to determine the EC50 and minimum effective concentration (MEC) that produced a decrease of E. coli growth rate, increased doubling time and percentage inhibition and reduced numbers of generations; all these values were derived from the fluorescence signals. Only Cr6+ and Hg2+ at two concentrations (0.25 and 0.5 mg l-1) almost completely inhibited this E. coli strain. All toxicant concentrations tested produced at least partial inhibitions of growth; Cr6+, Hg2+ and Cd2+, in that order, were most toxic, and Pb2+ the least. Zn2+ gave higher EC50 values at 3 h of incubation than at 4 h. The method was simple, rapid and inexpensive and would permit a large number of samples to be tested quickly.

Biological Assay↗
PubMedDate not supplied

Serology, clinical manifestations and treatment of brucellosis in different age groups.

We prospectively studied 339 patients diagnosed of brucellosis over a six year period in order to evaluate the clinical and serological characteristics of brucellosis in the elderly. 319 patients (94.1%) were under 65 years of age (group A), and 20 patients (5.9%) were older than 65 (group B). No patient in group B developed splenomegaly as opposed to 69 (21.6%) in group A (p less than 0.05). The percentage of positive blood cultures (Brucella melitensis isolated in all cases) was 72.1% in group A and 60% in group B. The mean titer of IgM antibodies measured by indirect immunofluorescence test was significantly lower in the elderly patients, with no other differences in serologic response between the two groups. 103 patients (32.2%) in group A and seven patients (35%) in group B developed some complications; spondylitis was more common and severe among group B patients. There was no therapeutic failure or relapse among patients over 65. We conclude that clinical, bacteriological and serological characteristics and the outcome of brucellosis in the elderly are similar to those seen in younger patients.

Adolescent↗
PubMedDate not supplied

Determinants of p,p-dichlorodiphenyldichloroethane (DDE) concentration in adipose tissue in women from five European cities.

To identify the determinants of p,p'-dichlorodiphenyldichloroethane (p,p'-DDE) in adipose tissue in subjects who participated in a cross-sectional study, we analyzed fatty acids, antioxidants, and p,p'-DDE in aspirates of adipose tissue of 328 postmenopausal women from 5 European countries. The overall mean of p,p'-DDE concentration was 1.66 microg/g of fatty acids (95% confidence interval = 1.46, 1.88). In a multiple-regression analysis, the main predictors of log10(p,p'DDE) were center of recruitment (p < .0001), adipose arachidic acid (p = .001), and adipose retinol (p = .04). These factors explained 14.9% of the overall variability of log10(p,p'-DDE). In our subjects, adipose tissue p,p'DDE concentrations were only weakly related with biomarkers reflecting intake of fish and other foods. This result is consistent with the notion that p,p'-DDE exists in different foods and, given the widespread contamination of the food chain, is relatively evenly distributed among foods.

Adipose Tissue↗
PubMedDate not supplied

[Molecular epidemiology of Salmonella enterica poisoning: correlation of the serotype and protein profile and plasmid DNA analysis].

Food-borne diseases nosocomial outbreaks due to Salmonella enterica strains have a high incidence nowadays. We describe here an outbreak that occurred in July 1990 in the Malaga University Hospital, that only involves one shift of health care workers. Salmonella enterica was detected in stool samples from HCW and a first analysis revealed the presence of two different antibiotic susceptibility patterns (resistotypes) among isolated strains. Two months after the outbreak started, the CNVIS (Majadahonda, Spain) confirmed the presence of two different serotypes (bovismorbificans and enteritidis). The delayed availability of the results (due to the lack of specific sera needed in most of the clinical Laboratories) was responsible for finishing only a partial and restricted epidemiologic study in terms of source identification for one particular serotype as well as for the antimicrobial resistance studies. The molecular identification techniques, particularly the electrophoretic protein profile could overcome these problems.

Antigens, Bacterial↗