[Utilization and practical significance of superficial electrocardiogram in the location of atrio-ventricular accessory pathways].
Explore the source record for details and available documents.
Adolescent↗
Biomedical subjects
J Campos
Publications and source records attributed to J Campos.
[New and re-emergent infectious diseases: their importance for public health].
Explore the source record for details and available documents.
Disease Outbreaks↗
[Penicillin-resistant meningococcus: a 12-year history?].
Explore the source record for details and available documents.
Humans↗
Determination of the Isotope Shift of the 000 Band of the First Singlet-Singlet Electronic Transition of Cl- and Br-Benzene in a Supersonic Beam
By using resonance-enhanced two-photon ionization in a supersonic beam, photoionization spectra of the 0(0)0 band of the first singlet-singlet electronic transition of 35Cl-, 37Cl-, 79Br-, and 81Br-C6H5 have been obtained at a rotational temperature of 1 K. The ions have been analyzed according to their masses in a time-of-flight mass spectrometer. From the spectra of 35Cl- and 37Cl-C6H5 obtained simultaneously, an isotope shift of 0.14 +/- 0.02 cm-1 has been determined. Similarly, from the spectra of 79Br- and 81Br-C6H5 the isotope shift resulted to be smaller than 0.02 cm-1. The spectra obtained have been interpreted by considering the geometrical structure and symmetry of each molecule, and values for the rotational constants and geometrical parameters in the upper and lower states have been obtained in agreement with the experimental results.
Journal Article↗
Tagging a Vibrio cholerae El Tor candidate vaccine strain by disruption of its hemagglutinin/protease gene using a novel reporter enzyme: Clostridium thermocellum endoglucanase A.
The celA gene encoding Clostridium thermocellum endoglucanase A was expressed in Vibrio cholerae on its own promoter and used to tag a candidate El Tor biotype cholera vaccine strain. Colonies of the tagged strain could be unequivocally distinguished by overlaying them with CM-cellulose indicator agar and Congo Red staining. Expression of celA did not affect growth of V. cholerae in vitro and in vivo. The celA gene was inserted in the chromosomal hap locus encoding V. cholerae hemagglutinin/protease, a putative "detachase", to create a hap- mutant that could be identified and scored by its halo of cellulolytic activity. The inactivation of hap had a positive effect on colonization in the infant mice model. The above results indicate that celA is a suitable marker gene for V. cholerae and hap is an appropriate locus for insertion of foreign DNA in vaccine development. Inactivation of hap, by increasing the duration of adherence, might decrease excretion of the resulting vaccine vector strain and thus increase its immunogenicity.
Animals↗
Bidirectional instrumental conditioning.
Three experiments examined bidirectional instrumental conditioning by training hungry rats to push a pole in one direction for food pellets and in the other for either a sugar or a starch solution. In the first study we examined whether the animals learned about the action-reinforcer relations using a specific satiety procedure. Prefeeding one type of reinforcer before an extinction test selectively depressed the performance of the action that had been paired with this reinforcer during training. The second experiment investigated the sensitivity of the bidirectional actions to variations in the action-reinforcer contingencies. When the instrumental contingency was degraded by presenting unpaired reinforcers, the animals pushed less in the direction that was paired with the reinforcer type that was the same as the non-contiguous one. A third study revealed that increasing the rate of reinforcement for one action enhanced its rate of performance without significantly affecting the performance of the other action. We conclude that the effects of reinforcer devaluation, the action-outcome contingency, and the rate of reinforcement are not mediated by Pavlovian associations between the manipulandum and the reinforcer.
Animals↗
Long-term persistence of ciprofloxacin-resistant Haemophilus influenzae in patients with cystic fibrosis.
Ciprofloxacin has been a major advance in the treatment of chronic respiratory infections. Three patients with cystic fibrosis and colonized by 5 nontypeable Haemophilus influenzae strains exhibiting low- (MIC, 2 microg/mL) and high-level ciprofloxacin resistance (MICs, 16-32 microg/mL) are described. The patients had received several courses of ciprofloxacin. These MICs represent a decrease in ciprofloxacin susceptibility of 200-3200 times. Molecular epidemiologic methods demonstrated that 2 patients were chronically colonized by their own ciprofloxacin-resistant strains for > or = 15-17 months. Three strains showed simultaneous resistance to ampicillin and chloramphenicol by enzyme inactivation, and 2 had ampicillin resistance without beta-lactamase activity. These data suggest that the emergence and long-term persistence of ciprofloxacin-resistant H. influenzae in patients with cystic fibrosis can be a consequence of antibiotic treatment.
Adult↗
Ciprofloxacin-resistant Haemophilus influenzae strains possess mutations in analogous positions of GyrA and ParC.
The nucleotide sequences of the quinolone resistance-determining regions of the gyrA and parC genes from five ciprofloxacin-resistant strains of Haemophilus influenzae (MICs, 2 to 32 micrograms/ml) isolated from patients with cystic fibrosis and three ciprofloxacin-susceptible strains of H. influenzae (MICs, < or = 0.1 micrograms/ml) were determined. Four of the five resistant strains possessed at least one amino acid substitution in each of the GyrA and ParC fragments studied. The mutations identified in GyrA were a serine at residue 84 (Ser-84) to Leu or Tyr and Asp-88 to Asn or Tyr. ParC mutations were in positions exactly analogous to those identified in GyrA, namely, Ser-84 to Ile and Glu-88 to Lys. The Glu-88 to Lys ParC substitution was identified only in high-level ciprofloxacin-resistant strains. These mutations have been shown to be the origin of the observed resistance after transformation into ciprofloxacin-susceptible H. influenzae isolates. These results suggest that H. influenzae isolates require at least one amino acid substitution in both GyrA and ParC in order to attain significant levels of resistance to quinolones.
Amino Acid Sequence↗
Genetic characterization of trimethoprim resistance in Haemophilus influenzae.
We previously demonstrated that trimethoprim (Tmp) resistance in Haemophilus influenzae is mediated by chromosomally encoded dihydrofolate reductase (DHFR) with a modified primary structure and distinct kinetic properties. To gain insight into the relationship of the DHFR structure and the level of Tmp resistance that it confers on the host bacterium, we cloned and characterized the folH genes of one Tmp-susceptible and two Tmp-resistant H. influenzae strains. Differences were observed between Tmp-susceptible and Tmp-resistant isolates both in the promoter region and in the coding sequences. The effect of differences between H. influenzae folH genes on Tmp susceptibility was investigated in Escherichia coli. Various folH gene hybrids were constructed, and their influence on Tmp susceptibility was determined. Resistance in E. coli mediated by folH from H. influenzae strain R1047 was associated with alterations in the promoter and the central part of folH. In contrast, the E. coli Tmp resistance phenotype associated with the folH gene of H. influenzae R1042 was characterized by alterations in one or more of three amino acid residues at the C-terminal part of the protein. These data indicate that Tmp resistance is not only related to alterations in the promoter region of the folH gene and the Tmp binding domains at the N-terminal and central part of DHFR. Alterations in the C-terminal part may also cause Tmp resistance, probably as a result of a change in secondary structure and the subsequent loss of Tmp binding affinity.
Amino Acid Sequence↗
Effects on bone mass of long term treatment with thyroid hormones: a meta-analysis.
Osteoporosis is the main cause of spine and hip fractures. Morbidity, mortality, and costs arising from hip fractures have been well documented. Thyroid hormones (TH) are widely prescribed, mainly in the elderly. Some studies (but not all) found a deleterious effect of suppressive TH therapy on bone mass. These conflicting data raised a controversy as to the safety of current prescribing and follow-up habits, which, in turn, raised major health-care issues. To look for a detrimental effect on bone of TH therapy, we performed a meta-analysis (by pooling standardized differences, using a fixed effect model) of all published controlled cross-sectional studies (41, including about 1250 patients) concerning the impact of TH therapy on bone mineral density (BMD). Studies with women receiving estrogen therapy were excluded a priori, as were studies with a high percentage of patients with postoperative hypoparathyroidism, when no separate data were available. We decided to stratify the data according to anatomical site, menopausal status, and suppressive or replacement TH therapy, resulting in 25 meta-analysis on 138 homogeneous subsets of data. The main sources of heterogensity between studies that we could identify were replacement or suppressive TH therapy, menopausal status, site (lumbar spine, femoral neck, Ward's triangle, greater trochanter, midshaft and distal radius, with various percentages of cortical bone), and history of hyperthyroidism, which has recently been found to impair bone mass in a large epidemiological survey. To improve homogeneity, we excluded a posteriori 102 patients from 3 studies, who had a past history of hyperthyroidism and separate BMD data, thus allowing assessment of the TH effect in almost all 25 subset meta-analyses. However, controls were usually not matched with cases for many factors influencing bone mass, such as body weight, age at menarche and at menopause, calcium dietary intake, smoking habits, alcohol intake, exercise, etc. For lumbar spine and hip (as for all other sites), suppressive TH therapy was associated with significant bone loss in postmenopausal women (but not in premenopausal women), whereas, conversely, replacement therapy was associated with bone loss in premenopausal women (spine and hip), but not in postmenopausal women. The detrimental effect of TH appeared more marked on cortical bone than on trabecular bone. Only a large long term prospective placebo-controlled trial of TH therapy (e.g. in benign nodules) evaluating BMD (and ideally fracture rate) would provide further insight into these issues.
Adult↗
[Botulinum A toxins in the treatment of spasticity in cerebral palsy during childhood].
We evaluated the safety and efficacy of Botulinum- A toxin (BTX) in patients with equinus deformity associated with cerebral palsy (CP). We prescribed BTX to six patients (all of whom had previously participated in a multicenter, randomized, double blind study of the same drug); treatment continued for at least 15 months. Four children showed striking improvement, being converted from toe-toe to consistent or occasional heel-toe gait. No side effects were observed. BTX appears to be safe and effective in patients with CP.
Adolescent↗
Genetic manipulation of Vibrio cholerae for vaccine development: construction of live attenuated El Tor candidate vaccine strains.
The recent spread of El Tor cholera to America augments the need for an effective, safe and economical vaccine. In the present paper we describe the construction of live attenuated V. Cholerae strains by specifically deleting the genes encoding cholera toxin and other putative toxins from the bacterial chromosome. To maximize the likelihood of exposing protective antigens relevant to currently circulating vibrios we selected for genetic manipulation recent epidemic V. cholerae isolates from Peru. The mutant strains did not produce cholera toxin in vitro and in vivo. Deletion of the virulence cassette was accompanied by marked attenuation in the infant mouse cholera model. A selected El Tor Ogawa candidate vaccine strain was refractory to acquisition of foreign genes by conjugation with toxigenic vibrios.
Animals↗
[Epidemiological characterization of Haemophilus influenzae using molecular markers].
BACKGROUND: Haemophilus influenzae is the etiological agent of acute- (meningitis, sepsis, pneumonia, epiglottis) and chronic infections (cystic fibrosis, chronic obstructive pulmonary infections). Several clinical (chronic infections) and epidemiological situations (community and hospital outbreaks) require the use of epidemiological typing methods. OBJECTIVE: We evaluated four typing methods to characterize clinical isolates of H. influenzae. METHODS: Forty-five clinical strains of H. influenzae were studied by biotype, serotype and antibiotype techniques, and the following methods: isoenzyme electrophoresis mobility, outer membrane proteins (OMP), ribotyping and pulsed field gel electrophoresis (PFGE). RESULTS: Type b strains had one pattern with Isoenzyme, OMP and ribotyping techniques. Only PFGE enabled us to differentiate between several type b patterns, although all of them were close related. All methods showed a great variety of patterns with the non-typable H. influenzae although clinical- or epidemiological-related strains had identical patterns. CONCLUSIONS: Results obtained with all four markers studied showed good agreement. Type b strains, in contrast to non-typable strains, had a strong clonal structure with all the assayed techniques; only PFGE showed differences. In terms of technical and financial cost, as well as reproducibility and discriminative power, we suggest as a markers for H. influenzae OMP and PFGE.
Bacterial Outer Membrane Proteins↗
Hexavalent-chromium reduction by a chromate-resistant Bacillus sp. strain.
Bacillus strain QC1-2, isolated from a chromium-polluted zone, was selected by its high ability to both tolerate and reduce hexavalent chromium [Cr(VI)] to less-toxic trivalent chromium [Cr(III)]. Cell suspensions of strain QC1-2 rapidly reduced Cr(VI), in both aerobic and anaerobic conditions, to Cr(III) which remained in the supernatant. Cr(VI) reduction was dependent on the addition of glucose but sulfate, an inhibitor of chromate transport, had no effect. Studies with permeabilized cells and cell extracts showed that the Cr(VI) reductase of strain QC1-2 is a soluble NADH-dependent enzyme.
Aerobiosis↗
EEG monitoring during endovascular embolization of cerebral arteriovenous malformations.
Arteriovenous malformations (AVMs) may have a bad prognosis. Endovascular embolization with cyanocrylate represents nowadays an important initial step in a staged treatment, that later may include surgery or radiotherapy. Embolization may induce significant changes in the dynamics of the cerebral circulation, some of which may provoke neurological sequelae. Therefore assessment of potential complications is usually done by using a superselective amytal test, during which small doses of amytal are injected directly in the pedicle that is going to be embolized. In spite of an extensive use of the EEG during endovascular embolization its evaluation in terms of benefits and limitations is not available. Such evaluation is therefore the aim of this work. EEG monitoring was performed during endovascular embolization of 19 patients; a large majority of patients presented large AVMs, with Spetzler indexes around IV or V. The main results were as follows: (1) EEG changes at baseline were significantly correlated with the AVM size and the Spetzler index but were unable to predict the difficulties in the embolization; (2) during amytal tests EEG positivity reached 35% and consisted mainly in ipsilateral slow focal activity; (3) in some cases embolization was performed in spite of transient EEG changes. It was found that focal or diffuse abnormalities in the lower frequency range, even when slight, could be followed by clinical hazards (3 out of 11 cases); (4) EEG monitoring was important in the prediction, evaluation and prognosis of clinical complications.
Adolescent↗
Effects of aerosolized pentamidine on glucose homeostasis and insulin secretion in HIV-positive patients: a controlled study.
OBJECTIVE: Intravenous pentamidine induces hypo- and hyperglycaemia (dose-dependent toxicity on islet beta cells), pancreatitis and nephrotoxicity. Conversely, aerosolized pentamidine (AP) is usually devoid of systemic side-effects: few reports of hypo- or hyperglycaemia have been published. Our study aimed to assess the influence on glucose homeostasis and insulin secretion of long-term exposure to AP used for prophylaxis of Pneumocystis carinii pneumonia in HIV-positive patients, and to compare the impact on insulin secretion of AP, whether administered for the first time or after prolonged monthly exposure. DESIGN: Retrospective cross-sectional controlled study (main objective) and non-randomized prospective controlled study. PATIENTS: We compared glucose homeostasis and C peptide response to 1 mg intravenous glucagon in patients who had previously inhaled > or = 10 prophylactic aerosols (group 1, n = 21) and in HIV-positive controls (groups 2 and 3, n = 28) who had received none. Both groups were comparable for age and body-mass index, but CD4 T-lymphocyte counts and Karnofsky scores were both significantly higher in the control group. RESULTS: Fasting (T0) blood glucose, fructosamine and response to the first glucagon test were similar in both groups, but postprandial glucose, glycated haemoglobin and fasting C peptide were significantly higher (P < 0.05) in the pentamidine group. A second glucagon test was performed on the same day, 3 h (T3) after AP inhalation in 35 patients (in 21 after > or = 10 aerosols, group 1; in 14 after the first, group 2) and in 14 HIV-positive controls (group 3). The only significant difference between the three groups in C peptide response to this second test was a lower peak T3/peak T0 ratio in group 1. Plasma amylase and creatinine were not altered by the aerosol. CONCLUSION: Long-term prophylactic exposure to AP had minor but significant effects on glucose homeostasis and insulin secretion but did not modify pancreatic and renal function. The detrimental effects induced by long-term exposure to AP found in our study are probably not clinically relevant, but a more prolonged exposure to AP might conceivably induce more severe alterations.
AIDS-Related Opportunistic Infections↗
Anticancer pyrimidine acyclonucleosides.
Several acyclonucleosides have been synthesized. Series 8 could liberate 5-FU and acrolein selectively in the tumour tissue whilst 9 only discharge 5-FU. The conformational analysis of 8 and 9 has been carried out by means of Molecular Mechanics, using the MM2 force field. It was observed that the open chain linked to the N-1 of the 5-FU moiety mimics the conformational structure of the sugar of desoxyuridine. Biological assays have been carried out in vitro on tumour growth in Ehrlich ascitic cells with the consequent decrease of 35% in the cellular mitosis. IC50 showed values between 3-45 microM for series 8 whilst series 9 were less active than 5-FU. Compared with that of 5-FU the acute and chronic toxicity is considerably decreased.
Animals↗
Carney's triad: apropos of a new case.
Carney's triad is defined by the coexistence of at least two of three rare disorders, including gastric epithelioid leiomyosarcoma (malignant leiomyoblastoma), pulmonary chondroma, and paraganglioma, most often extra-adrenal and functioning. We report a new case in a 10-year-old girl. The paraganglioma, although nonfunctioning, was detected after it was searched for, as Carney's triad was suspected. Unrelated seems the development of breast fibroadenomas in the same patient. Whenever a patient with one component of the triad is encountered, the possibility of this syndrome should be considered and the other two components sought.
Breast Neoplasms↗