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Biomedical subjects

L Monteiro

Publications and source records attributed to L Monteiro.

At least 37 records · Page 2Linked to original sources
PubMed1998

Microbiological aspects of antibiotic resistant Helicobacter pylori strains.

Resistance of Helicobacter pylori to antibiotics has been described for macrolides, nitroimidizoles, and fluoroquinolones. In 1996, the mechanism of resistance to macrolides was determined to be a point mutation on the 23S rRNA which leads to decreased binding of macrolides to the ribosome. Recently, mutations in the gene coding for nitroreductase have been linked to resistance to nitroimidazoles but more work will be necessary to determine whether this is the only mechanism involved. Point mutations have also been associated with resistance to fluoroquinolones. A decreased susceptibility to amoxicillin has been observed and may be linked to changes in the penicillin binding proteins. The same phenotypic methods generally used to test antibiotic susceptibility can be applied to Helicobacter pylori. The disk diffusion method can be used for macrolides, the E-test for amoxicillin, and the point limit method for nitroimidazoles but the reference method of all of these is the agar dilution method. Molecular methods such as polymerase chain reaction-RFLP and various techniques using hybridization can also be employed but to date they have only been used for macrolides. These techniques have the advantage that they can be applied directly to the biopsy specimen.

Anti-Infective Agents↗
PubMed1997

Quantitative polymerase chain reaction for the detection of Helicobacter pylori in gastric biopsy specimens.

A variety of methods, including the polymerase chain reaction (PCR), are available for the detection of Helicobacter pylori in clinical samples, but none of them can adequately quantify the organism. In the present study, the competitive PCR, a rapid and simple method for quantification of Helicobacter pylori DNA in gastric biopsies, was used to measure the amount of DNA present in Helicobacter pylori-positive biopsies. This method is based on coamplification of an internal standard and a target DNA sequence with one set of primers. The internal standard was prepared using a nonhomologous fragment of DNA ligated to specific primers used to amplify the target DNA. This competitive DNA fragment of a desired size and containing primer templates is called a PCR MIMIC. To perform a quantitative PCR, PCR amplification reactions were spiked with known quantities of PCR MIMICs containing unknown amounts of DNA from Helicobacter pylori-positive biopsies. The amount of target DNA was determined by visual comparison of the PCR products after establishment of the correlation between the internal control concentration and the DNA concentration in a competitive amplification reaction. The results were confirmed by a radioactive method. Quantitative PCR can be a reliable method for determining the extent of Helicobacter pylori infection.

Biopsy↗
PubMed1997

Evaluation of performances of three DNA enzyme immunoassays for detection of Helicobacter pylori PCR products from biopsy specimens.

PCR is recognized as a promising method for the detection of Helicobacter pylori in gastric biopsy specimens. However, detection of PCR products by gel electrophoresis is difficult to implement in routine clinical laboratories. The aim of this study was to compare three new DNA enzyme immunoassays with the standard method in their ability to detect PCR products. The three assays were based on the amplification of a fragment of the ureC gene of H. pylori and a colorimetric hybridization assay. The first assay (GEN-ETI-K DNA enzyme immunoassay; Sorin, Sallugia, Italy) was based on the hybridization of amplified DNA with a probe bound in microtiter wells and detected with labelled anti-DNA antibody. The second assay (Pylori-prob; Biocode, Sclessin, Belgium) comprised a solid-phase sandwich hybridization system with a specific biotinylated probe being used for detection. Finally, the third assay (PCR enzyme-linked immunosorbent assay; Boehringer, Mannheim, Germany) was based on the hybridization of amplified DNA labelled with digoxigenin as a probe (used as a coating in microtiter wells) and detected with antidigoxigenin-peroxidase as conjugate. The sensitivity of the colorimetric assay was evaluated by using amplification products from PCR assays performed on several 10-fold dilutions of DNA from H. pylori CIP 101260, and the specificity was assessed with different urease-positive bacteria. Biopsy specimens from 199 patients were tested; 106 were classified as H. pylori positive, and 93 were classified as H. pylori negative by culture and/or histological examination as the "gold standard." The receiving operating characteristic curve was used to determine the best cutoff point for each assay. The detection of PCR products by colorimetric hybridization increases the sensitivity up to 100-fold compared to that with gel electrophoresis. The results are rapid (4 h) and easy to interpret and can be automated.

Biopsy↗
PubMed1997

Complex polysaccharides as PCR inhibitors in feces: Helicobacter pylori model.

A model was developed to study inhibitors present in feces which prevent the use of PCR for the detection of Helicobacter pylori. A DNA fragment amplified with the same primers as H. pylori was used to spike samples before extraction by a modified QIAamp tissue method. Inhibitors, separated on an Ultrogel AcA44 column, were characterized. Inhibitors in feces are complex polysaccharides possibly originating from vegetable material in the diet.

Feces↗
PubMed1995

Spectrum of epilepsy in neurocysticercosis: a long-term follow-up of 143 patients.

To characterize the clinical profile and the prognostic factors of the epilepsy due to parenchymal neurocysticercosis (NCC) 143 patients were analysed. Patients (62 men, 81 women) had a mean age at epilepsy onset of 29 years (range 2-71), mean epilepsy duration of 16 years (range 1-58) and mean follow-up of 5.2 years. Seizures were generalised tonic-clonic (GTC) in 50 patients (35%), simple partial (SP) in 66 (46%) and complex partial (CP) in 27 (19%). Epilepsy began as a single seizure in 73% and as a cluster of seizures or status epilepticus in 27%. Seizures were controlled in 64% of patients. Multivariate analysis revealed that significant prognostic factors associated with seizure control were type of seizures and age at epilepsy onset. Control is more likely in GTC and SP seizures and in patients with a higher age at seizures onset. Our analysis establishes that epilepsy due to NCC is a heterogeneous syndrome concerning age and mode of onset, seizure type, duration of epilepsy and pattern of evolution probably related with different pathogenic mechanisms.

Adolescent↗
PubMed1993

Active neurocysticercosis, parenchymal and extraparenchymal: a study of 38 patients.

In this retrospective study we have analysed a series of 38 patients seen from 1983 to 1992 (mean follow-up, 4.5 years) with active neurocysticercosis (NCC), 23 (60.5%) with parenchymal and 15 (39.5%) with extraparenchymal NCC. Classification into these two forms of NCC was based on computed tomography and magnetic resonance imaging criteria. The enzyme-linked immunosorbent assay performed in cerebrospinal fluid, for anti-Taenia solium antibodies, was positive in 18 of 23 (78%) cases. Epilepsy and/or intracranial hypertension were the most common clinical presentation (92%). Twenty-three (60.5%) of 38 patients were treated with praziquantel and/or albendazole. In parenchymal NCC, the efficacy of medical therapy was complete in 13 of 16 (81%) and partial in 3 of 16 (19%) patients. In contrast, in all cases of extraparenchymal NCC treated with cysticidal drugs the results were disappointing. A ventriculoperitoneal shunt was performed in 9 of 13 patients with extraparenchymal NCC and hydrocephalus. Severe complications, including two deaths, associated with the natural evolution of the disease or with surgery, occurred only in extraparenchymal NCC. Therefore, we confirm the existence of the two forms of active NCC, parenchymal and extraparenchymal, which are strikingly different in clinical presentation, medical therapy response, complications, morbidity and mortality.

Adolescent↗
PubMed1993

Case report: cyclosporin A-induced neurotoxicity.

Acute encephalopathy is a recognized toxic effect of Cyclosporin A (CsA) in organ transplantation recipients. A 16-year-old girl presented with acute encephalopathy 2 weeks after CsA and methylprednisolone medication for idiopathic uveitis. Magnetic resonance imaging showed cortical and white matter occipital changes, which were not visible 2 months later. With expanding indication for CsA use, an increasing number of neurotoxic cases are to be expected.

Adolescent↗
PubMed1992

Spontaneous thoracolumbar spinal cord infarction: report of six cases.

We present a retrospective study of 6 patients with spinal cord infarction in the territory of the Adamkiewicz artery. In all patients, the clinical picture was stereotyped: sudden onset of paraplegia and bilateral radicular pain, dissociated sensory loss below the level of infarction and sphincter dysfunction. Emergency neuroradiological investigation ruled out a compressive lesion in all cases. In one patient, spinal angiography was performed and identified an occlusion of the Adamkiewicz artery. Treatment was supportive and all patients had a substantial recovery over a period of weeks.

Aged↗
PubMed1985

Staff burnout in a hospice setting.

Burnout is a job-related state characterized by emotional and physical exhaustion which can be caused by intense involvement over an extended period of time with people who are experiencing psychological and/or physical problems. People working in the health care professions have been identified as being particularly at risk for experiencing burnout. Based on hospice staff survey data collected as a part of the National Hospice Study (NHS), this paper describes multivariate analyses of selected demographic, occupational, and organizational predictors of burnout. Findings indicated that younger, better-educated staff are more prone to burnout, as are staff who work on a full-time basis in direct contact with patients. None of the hospice organizational factors tested were significantly related to burnout. Further research is necessary to determine whether or not such factors as staff support systems are effective in mitigating burnout among staff in the health care field.

Adolescent↗