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Biomedical subjects

J Salgado

Publications and source records attributed to J Salgado.

At least 55 records · Page 3Linked to original sources
PubMed1992

Some morphologic changes induced by Nd:YAG laser on the noncoated enamel surface: a scanning electron microscopy study.

The enamel surface layer of some human teeth was treated with the low-energy Nd:YAG laser at 8 mJ pulse energy. These samples were previously etched with 0.05 M orthophosphoric acid to reduce the surface reflection. The treated samples, as well as the control samples, were widely studied by scanning electron microscopy, and, in the lased group, significant morphologic changes affecting the enamel surface were observed. Those changes reveal principally the loss of the typical surface structure of the acid-etched enamel. The hydroxyapatite prisms were not discernible, and there was a decrease in the roughness of the lased surface enamel. These laser-induced structural changes may be related to the increased resistance to the calcification reported by many authors.

Acid Etching, Dental↗
PubMed1992

1H NMR and UV-Vis spectroscopic characterization of sulfonamide complexes of nickel(II)-carbonic anhydrase. Resonance assignments based on NOE effects.

The binding of acetazolamide, p-fluorobenzensulfonamide, p-toluenesulfonamide, and sulfanilamide to nickel(II)-substituted carbonic anhydrase II has been studied by 1H NMR and electronic absorption spectroscopies. These inhibitors bind to the metal ion forming 1:1 complexes and their affinity constants were determined. The 1H NMR spectra of the formed complexes show a number of isotropically shifted signals corresponding to the histidine ligands. The complexes with benzene-sulfonamides gave rise to very similar 1H NMR spectra. The NMR data suggest that these aromatic sulfonamides bind to the metal ion altering its coordination sphere. In addition, from the temperature dependence of 1H NMR spectra of the p-fluorobenzenesulfonamide adduct, a conformational change is suggested. The T1 values of the meta-like protons of the coordinated histidines have been measured and resonance assignments based on NOE experiments were performed.

Acetazolamide↗
PubMed1992

Biological characterization of a formulated allergoid from Dermatophagoides pteronyssinus.

A comparative study between the biological properties of the allergen Dermatophagoides pteronyssinus (Dp) and its formulated allergoid (DpHCHO) was performed. After immunizing rats with Dp or DpHCHO the serum level time course of IgE and IgG was determined by passive cutaneous anaphylaxis (PCA) and indirect-ELISA, respectively. The avidity for IgE (PCA and PCA-inhibition) or IgG (indirect ELISA and ELISA inhibition) and the ability to induce anaphylactic shock were also determined. Serum IgE pattern differs between Dp and DpHCHO while IgG levels were greater after DpHCHO. The allergoid has lost the ability to bind IgE while its avidity for IgG falls 5-6 times. The allergoid, but not the allergen, fails to induce anaphylactic shock. A schedule for assaying the biological characteristics of allergoids is presented.

Allergens↗
PubMed1992

Direct membrane-damaging effect of sertaconazole on Candida albicans as a mechanism of its fungicidal activity.

The direct action of 7-chloro-3-[1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)ethoxy- methyl]benzo[b]thiophene (sertaconazole, FI-7045, CAS 99592-32-2) on the membrane integrity of C. albicans is studied by quantifying the leakage of intracellular adenosine triphosphate (ATP) into the medium as an index of the changes in membrane permeability and integrity and cell viability of the culture used. Sertaconazole caused a dose-dependent decrease in intracellular ATP after only 10-min exposure and a concomitant significant increase in extracellular ATP. This behaviour is characteristic of antifungals which are fungicidal as a result of a direct membrane damage. Thus sertaconazole, in addition to the mechanism of action responsible for its fungistatic activity (inhibition of ergosterol synthesis), has a second mechanism of action providing a significant fungicidal activity due to direct cell membrane damage.

Adenosine Triphosphate↗
PubMed1990

Interaction of sulphate and chloride with cobalt(II)-carbonic anhydrase.

The interaction between Cobalt(II)-Bovine Carbonic Anhydrase II and the inhibitors sulphate and chloride have been investigated through 1H NMR and electronic absorption spectroscopies. Both inhibitors bind to the metal ion forming a 1:1 adduct and the corresponding affinity constants have been determined. These inhibitors interact weakly with CoBCA II and this interaction only occurs at low pH values. The T1 values of the meta-like protons of the coordinated histidines have been measured. The coordination number of the metal ion in the adducts is discussed on the basis of temperature dependence of the isotropic shifts, T1, and molar absorbance values.

Carbonic Anhydrase Inhibitors↗
PubMed1990

Specific IgG and IgE responses to Dermatophagoides pteronyssinus in Sprague-Dawley rats.

Specific IgG and IgE antibodies against the mite Dermatophagoides pteronyssinus (Dp) have been determined in the serum of Sprague Dawley (SD) rats by enzyme linked immunosorbent assay (ELISA) and passive cutaneous anaphylaxis (PCA), respectively. Immunization of rats with Dp produces a rapid increase of serum specific IgE antibody levels which decrease when specific IgG antibodies start rising. The results indicate that the SD rat is a good model to induce a humoral immune response to allergen Dp.

Animals↗
PubMed1989

[Introduction of an enzyme method for determining pyrophosphate in urine--a comparative study between patients with calculi and normal probands].

Interest aroused towards pyrophosphate as a possible inhibitor in calcium oxalate and phosphate lithiasis. A procedure for the quantitative determination of pyrophosphate in urine suitable for use in clinical laboratories is described. The reproducibility of the method was assessed by within-run and between-run reproducibility studies and the accuracy of the method was obtained by determining the amount of pyrophosphate recovered in urine samples. The present study compares the pyrophosphate excretion and concentration between a control group and a calcium oxalate stone former group.

Calcium Oxalate↗
PubMed1985

The variability of fetal breathing movements in normal human fetuses at term.

With the use of a B-scan phase-locked tracking system, 108 observations of fetal breathing were performed on 97 normal antenatal patients at term. One hundred thirty-three recorded segments of fetal breathing movements were obtained. Breath-to-breath variability was analyzed in 79 segments and expressed as a coefficient of variability. The mean coefficient of variability was 28.6% +/- 13.2%, and a histogram plot revealed a normal distribution. All fetuses had normal antepartum testing and all Apgar scores and neonatal courses were normal. The potential application of human fetal breathing variability as a test for fetal health is discussed.

Female↗
PubMed1984

Prolonged pregnancy: surveillance of the fetus and the neonate and the course of labor and delivery.

The perinatal events in 184 term control pregnancies and 129 prolonged pregnancies were prospectively compared. Fetal surveillance consisted of weekly biophysical profile testing. Thirty-two infants were dysmature, and 10 of these had advanced dysmaturity. The incidence of advanced dysmaturity rose quickly after 44 weeks. This group was at greater risk for fetal distress, lower Apgar scores, and emergency cesarean section. The combination of oligohydramnios, a suboptimal nonstress test, and a low profile score was highly predictive of a neonate with advanced dysmaturity. In the control pregnancies, the rate of induction of labor was 13.81% compared with 39.84% in the prolonged pregnancies. The induced labor group had a 51.32% cesarean section rate. Our approach to prolonged pregnancy consists of elective induction of labor when the cervix is favorable and biweekly profile testing when it is not; however, the high incidence of advanced dysmaturity after 44 weeks warrants delivery.

Apgar Score↗
PubMed1975

Replication of the Achievement Place model in California.

Attempting to replicate procedures from Achievement Place, token reinforcement procedures were used to modify savings, conversational interruptions, and table-setting of delinquent boys residing in a home-style, community based, treatment setting. The tokens (points) were redeemable for various privileges and could be earned for specified appropriate behaviors and lost for specified inappropriate behaviors. Contingent point fines reduced the frequency of interruptions. Point rewards improved table-setting, but even large point rewards did not substantially increase savings. Baseline data indicated that lateness to dinner was not a problem, as it was in Achievement Place. Withdrawal of contingent points and back-up rewards did not disrupt the clean-up behavior of two boys.

Adolescent↗
PubMedDate not supplied

Monte Carlo studies for irradiation process planning at the Portuguese gamma irradiation facility.

The paper describes a Monte Carlo study for planning the irradiation of test samples for microbiological validation of distinct products in the Portuguese Gamma Irradiation Facility. Three different irradiation geometries have been used. Simulated and experimental results are compared and good agreement is observed. It is shown that Monte Carlo simulation improves process understanding, predicts absorbed dose distributions and calculates dose uniformity in different products. Based on these results, irradiation planning of the product can be performed.

Computer Simulation↗
PubMedDate not supplied

Septic arthritis following arthroscopic meniscus repair: a cluster of three cases.

Three cases of Staphylococcus epidermidis septic arthritis following inside-out arthroscopic meniscus repair within a 4-day period at the same facility are described. All three patients responded to surgical debridement and 4 to 6 weeks of intravenous antibiotics. In each instance, the meniscus and repair sutures were left intact; 12- to 38-month follow-up revealed no evidence of infection or meniscal symptoms. Epidemiological investigation implicated the meniscus repair cannulas as one of the few factors common to all three cases. Molecular typing of bacterial DNA revealed that two of the three isolated organisms showed identical pulsed-field gel electrophoretic patterns, implying a common source of inoculation. Experimental contamination of the cannulas revealed that only sterilization involving ultrasonification, lumen washing by water jet, and steam sterilization resulted in clean and sterile cannulas.

Adult↗
PubMedDate not supplied

Comparative in vitro antifungal activity of amphotericin B lipid complex, amphotericin B and fluconazole.

Amphotericin B (AMB) is considered the gold standard in the treatment of serious systemic mycoses in spite of its nephrotoxicity and adverse effects. Association with lipids enables larger doses of AMB to be given with a longer t((1/2)) and C(max), without the toxic effects at lower concentrations. Liposome-encapsulated AMB shows a lower affinity for mammalian cells and improves V(d), thus decreasing toxicity. Amphotericin B lipid complex (ABLC) is an AMB formulation associated with a biodegradable phospholipid matrix (5% molar) from which the drug is released by cell phospholipases. ABLC is recommended for serious mycoses refractory to conventional antifungal therapy or when AMB is contraindicated. We compared the in vitro antifungal activity of ABLC, AMB and fluconazole (FLZ) against 328 strains of clinically significant opportunistic fungi using a microdilution method (NCCLS, M-27A). 64.9% of the yeasts were inhibited by MIC of ABLC </= AMB resulting in a similar or slightly superior efficacy compared to AMB when tested against Candida albicans, C. glabrata, C. guilliermondii, C. parapsilosis and C. tropicalis. Effectiveness against C. krusei was lower for ABLC (5.99 microg/ml for ABLC, 1.58 microg/ml for AMB). However, for Aspergillus fumigatus, the activities of AMB and ABLC were 1.62 and 2.46 microg/ml, respectively; A. niger 0.72 microg/ml, 0.76 microg/ml (ABLC and AMB, respectively); A. clavatus, A. candidus, A. tenuissima, A. corymbifera and Exophiala jeanselmei, Scedosporium spp. and Miceliophtora spp. showed a low susceptibility to both AMB formulations. ABLC is a useful alternative to AMB or FLZ for the treatment of severe fungal infections, due to the broad spectrum of antifungal actions observed in this study.

Amphotericin B↗
PubMedDate not supplied

In vitro susceptibility of Candida dubliniensis to current and new antifungal agents.

BACKGROUND: Candida dubliniensis is a recently described Candida species closely related to Candida albicans, which has been associated with oral candidiasis in HIV-infected patients. Fluconazole-resistant strains of C. dubliniensis are easily obtained in vitro and this fact could be a complication if this resistance develops during treatment with this drug. METHODS: In the present study, the in vitro antifungal susceptibilities of 36 C. dubliniensis clinical isolates and culture strains to current and new antifungal agents, such as amphotericin B (AMB), amphotericin B lipid complex (ABLC), amphotericin B colloidal dispersion (ABCD), 5-fluorocytosine (5FC), fluconazole (FLC), itraconazole (ITC), ketoconazole (KTC), liposomal amphoteri- cin B (LAMB), liposomal nystatin (LNYT), LY303366 (LY), SCH56592 (SCH), and voriconazole (VRC), were determined according to the National Committee for Clinical Laboratory Standards M27-A broth microdilution method for yeasts. RESULTS: Most isolates of C. dubliniensis were susceptible to both new and current antifungal drugs, with 75.9% isolates susceptible to KTC, 86.2% to FLC and to ITC, and approximately 100% to the other antifungal agents tested. The cross-resistance phenotypes are detailed. Four isolates were resistant (MIC > or =64 microg/ml) to FLC. These 4 isolates were also resistant to KTC, and 3 of them were also resistant to ITC (MIC > or =1 microg/ml for both agents). However, these isolates were highly susceptible to 5FC and all polyene formulations (AMB, ABLC, ABCD, LAMB, and LNYT), triazole (SCH and VRC) and echinocandin (LY) antifungal agents. CONCLUSION: The new liposomal and lipidic formulations of AMB, LNYT, and the new triazoles and echinocandins may provide new alternatives to FLC for the treatment of infections by C. dubliniensis.

Amphotericin B↗
PubMedDate not supplied

Effect of adjuvants on IgG and IgE response to ovalbumin in rats.

Specific and total IgG and IgE serum levels were measured in Sprague-Dawley rats after immunization with ovalbumin (OA). OA was administered in an aqueous solution, suspended in alum or in Complete Freund's Adjuvant (CFA) with or without simultaneous administration of Bordetella pertussis (Bp). Control groups received only saline, alum or CFA. Specific IgG, total IgG and total IgE were determined by ELISA methods. Specific IgE was biologically evaluated. The highest specific IgG and IgE antibody responses were obtained with OA suspended in alum, while Bp failed to potentiate this response. The low specific response seen with OA suspended in CFA was potentiated when Bp was simultaneously dosed. Total IgE levels were increased in those groups receiving Bp. The contribution of specific IgG or IgE response to the total IgG or IgE levels was not distinguished with this experimental procedure. It can be concluded that immunization with OA suspended in alum induces appreciable increases in specific IgG and IgE antibodies without significantly affecting total IgG and IgE levels.

Adjuvants, Immunologic↗
PubMedDate not supplied

Chronic inflammation induced by type I collagen in rats.

In this study we attempt to investigate if collagen type 1 from bovine Achilles tendon is capable of causing an inflammatory response. Thus, we immunized rats with a collagen emulsion injected in the right hind paw, via subplantar, and intradermally on the back. Seven days later, the rats were reimmunized by intradermal injection on the base of the tail with an identical emulsion. The inflammatory response was assessed by measuring the hind paw swelling of the rats every seven days for two months. We also analysed the levels of anticollagen antibodies in each rat during the experimental period. An indirect microELISA method was developed to determine collagen-specific-antibodies in rat serum. We observed a chronic inflammation in 41% of immunized rats. This pathology results in local swelling in the hind paw that remained for at least two months. This model was accompanied with the production of antibodies against collagen that appeared on day 14 after induction and remained during the study period (56 days). A positive correlation between swelling and antibody titre was observed.

Animals↗
PubMedDate not supplied

ELISA for quantification of specific IgG and IgE antibodies to ovalbumin.

Two indirect microELISA methods have been developed to determine ovalbumin (OA)-specific IgG and total OA-specific antibodies in rat's serum. Animals were immunized with OA suspended in alum s.c. and administered i.p. with Bordetella pertussis (Bp). The study was performed using serum samples taken 14 days after immunization. Anti-OA IgG, anti-OA Ig (by indirect ELISA), total IgE and total IgG (by ELISA sandwich) and also anti-OA specific IgE (by passive cutaneous anaphylaxis test) were measured. The OA concentration to coat the solid phase was 1.25 micrograms/ml. The optimal serum dilution for measuring OA-specific antibodies by the indirect ELISAs developed was between 1/640-1/1280, for both methods. Conjugate concentrations used were 1/12800 (PO-anti rat IgG) and 1/600 (PO-anti rat Ig). Considering both methods, the intra and inter-assay variability coefficients oscillate between 1.98 and 6.75%. The immunization procedure used produces a marked increase in anti-OA Ig, anti-OA IgG and specific IgE levels. The immunization does not modify total IgG levels whereas total IgE values were significantly higher. This increase can be attributed chiefly to the non-specific IgE production induced by Bp. The microELISA methods proposed in this work, are reasonable alternatives radiolabelled techniques to measure OA-specific antibodies.

Animals↗