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Biomedical subjects

M L García

Publications and source records attributed to M L García.

At least 19 recordsLinked to original sources
PubMed2006

Flurbiprofen loaded biodegradable nanoparticles for ophtalmic administration.

Poly(lactic/glycolic) acid nanoparticles incorporating flurbiprofen (FB) were prepared by the solvent displacement technique using poloxamer 188 as a stabilizer to improve the availability of the drug for the prevention of the inflammation caused by ocular surgery. A 2(3) + star design was applied to investigate the influence of several factors such as the pH of the aqueous phase, the initial concentration of the stabilizer, and the drug used to prepare the nanoparticles (NPs) on the physicochemical properties (particle size analysis, zeta potential, and drug loading efficiency) of the colloidal system. The best formulations were those prepared at pH 3.5 with a concentration of 1.5 mg/mL of FB and 10 or 20 mg/mL of poloxamer 188. These formulations showed an appropriate average size for ophthalmic administration (232.8 and 277.6 nm, respectively) and a good yield of entrapment efficiency (94.60% and 93.55%, respectively). The release behavior of FB from the developed NPs was complete and exhibited a biphasic pattern. Formulations did not show toxicity on ocular tissues. In vivo anti-inflammatory efficacy was assessed in the rabbit eye after topical instillation of sodium arachidonate (SA). A higher decrease of the SA-induced inflammation was obtained for the NP formulations.

Animals↗
PubMed2006

Genetics of litter size in three maternal lines of rabbits: repeatability versus multiple-trait models.

Variance components were estimated in 3 lines of rabbits selected for litter size at weaning (A, Prat, and V) to test one of the assumptions of the models used for selection: that litter size data at different parities are repeated measurements of the same trait. Multiple-trait analyses were performed for the total number of kits born (TB), the number of kits born alive (BA), and the number of kits weaned (NW) per litter. Estimates were obtained by REML in multivariate analyses, including all of the information of the selection criteria, under a repeatability model or a multiple-trait model, considering litter size at the first, second, and subsequent parities as different traits. Models included the fixed effects of the physiological status of the female and the year-season of mating day, buck and doe random permanent environmental effects, and doe additive genetic effects. Results indicated that prolificacy was determined mainly by doe components and that the service sire had a very small effect. Heritabilities for the first and second parities were greater than the estimates obtained under the repeatability model (0.04 to 0.14 for the repeatability model). In the A and V lines, similar values of heritability were found at the first and second parities, but in the Prat line heritability at the second parity was always greater than at the first and greater parities (values of 0.21, 0.17, and 0.15 for TB, BA, and NW, respectively, in second parities of the Prat line). Genetic correlations between the same traits at different parities were approximately 0.8 for all traits in line A, but much lower in the other 2 lines. On average, the values were 0.64 for TB, 0.48 for BA, and 0.39 for NW between the first and second parities, and 0.65 for TB, 0.56 for BA, and 0.45 for NW between the first and third and greater parities. Genetic correlations between the second and greater parities showed the greatest values (approximately 0.8) in lines A and Prat for all traits, but they were lower in line V (0.63 for BA and 0.37 for NW). The heterogeneity of heritabilities and genetic correlations between parities lower than 0.9 suggests that litter size at different parities could be considered as different traits when genetic evaluations are performed. However, when the accuracies of predicted breeding values under a multiple-trait and a repeatability model were calculated, assuming the first to be the true model, the values obtained were nearly the same for all traits in all lines.

Animals↗
PubMed2005

Ultrastructural changes and structure and mobility of myowater in frozen-stored hake (Merluccius merluccius L.) muscle: relationship with functionality and texture.

The ultrastructural changes and the main Raman spectral features of water (3100-3500 and 50-600 cm(-)(1) ranges) in frozen-stored hake were studied with the aim of connecting these changes with loss of some functional properties such as water holding capacity, and with modifications of muscle texture. The following results were obtained: (a) The changes in the spaces between myofibrils can be related to modifications of shear resistance. (b) The behavior of the strong 160 cm(-)(1) band can be related to conformational transitions of muscle proteins, to changes in the structure of muscle water, and/or to alterations in protein-water interactions. (c) There were intensity changes in the nu(s)(OH) band that may be attributable to transfer of water to larger spatial domains during frozen storage.

Animals↗
PubMed2005

Destruction of Salmonella Senftenberg on the shells of intact eggs by thermoultrasonication.

The combined effect of ultrasonic waves and heat treatment applied simultaneously was evaluated on the survival of strains of Salmonella Senftenberg on shells of intact eggs. This combined process has a higher killing effect than heat treatment alone. The decimal reduction times (D-values) were decreased by 65.2 to 11.1% in the temperature range studied (57.8 to 67 degrees C). In contrast to the effect on Salmonella enterica serovar Enteritidis in a previous study, thermoultrasonication had no important advantage for elimination of Salmonella Senftenberg. However, because 52 degrees C is a nonlethal temperature for Salmonella Senftenberg, the conditions used for the elimination of Salmonella Enteritidis (52 degrees C for 12 min) in the previous study would be equivalent to ultrasonic treatment alone in the present study. This thermoultrasonication treatment may result in a 100-fold greater reduction of Salmonella Senftenberg than that achieved by common in-shell egg pasteurization (60 degrees C for 3.5 min).

Animals↗
PubMed2004

The complete nucleotide sequence of a Spanish isolate of Citrus psorosis virus: comparative analysis with other ophioviruses.

The complete genomic sequence (11278 nt) of Citrus psorosis virus (CPsV), isolate P-121 from Spain, was determined and compared with those from isolate CPV-4 and from other ophioviruses. The three RNAs of P-121 had similar size and identical organization as those of CPV-4. The 24K and the RdRp proteins were potentially encoded in the viral complementary (vc) strand of RNA 1, the 54K protein potentially encoded in vcRNA 2 and the coat protein encoded in vcRNA 3. These four proteins from P-121 and CPV-4 had 87, 92, 93 and 94% amino acid identity, respectively, but only 22, 38, 25 and 33% identity with their homologous proteins from Mirafiori lettuce big vein virus (MLBVV), the only other ophiovirus completely sequenced. Biological and genetic differences between CPsV and MLBVV (and the other ophioviruses), would support their future allocation in different genera within a tentative family Ophioviridae.

Base Sequence↗
PubMed2004

Simultaneous detection of fourteen respiratory viruses in clinical specimens by two multiplex reverse transcription nested-PCR assays.

There is a need for rapid, sensitive, and accurate diagnosis of lower respiratory tract infections in children, elderly, and immunocompromised patients, who are susceptible to serious complications. The multiplex RT-nested PCR assay has been used widely for simultaneous detection of non-related viruses involved in infectious diseases because of its high specificity and sensitivity. A new multiplex RT-PCR assay is described in this report. This approach includes nested primer sets targeted to conserve regions of human parainfluenza virus haemagglutinin, human coronavirus spike protein, and human enterovirus and rhinovirus polyprotein genes. It permits rapid, sensitive, and simultaneous detection and typing of the four types of parainfluenza viruses (1, 2, 3, 4AB), human coronavirus 229E and OC43, and the generic detection of enteroviruses and rhinoviruses. The testing of 201 clinical specimens with this multiplex assay along with other one formerly described by our group to simultaneously detect and type the influenza viruses, respiratory syncytial viruses, and a generic detection of all serotypes of adenovirus, covers the detection of most viruses causing respiratory infectious disease in humans. The results obtained were compared with conventional viral culture, immunofluorescence assay, and a third multiplex RT-PCR assay for all human parainfluenza viruses types described previously. In conclusion, both multiplex RT-PCR assays provide a system capable of detecting and identifying simultaneously 14 different respiratory viruses in clinical specimens with high sensitivity and specificity, being useful for routine diagnosis and survey of these viruses within the population.

Coronavirus↗
PubMed2004

Cytochemical location of urease in the cell wall of two different lichen phycobionts.

The enzyme urease has been located in the cell wall of recently isolated phycobionts from Evernia prunastri and Xanthoria parietina lichens. Cytochemical detection is achieved by producing a black, electron-dense precipitate of cobalt sulfide proceeding from CO(2) evolved from urea in the presence of cobalt chloride. Cellular fractionation reveals that about 80% of total urease activity was associated to the cell wall on both phycobionts whereas only 20% was recovered as soluble protein.

Cell Fractionation↗
PubMed2004

Stability and ocular tolerance of cyclophosphamide-loaded nanospheres.

The physical and chemical stabilities of several formulations of cyclophosphamide-loaded polybutylcyanoacrylate (PBCA) nanospheres developed for an ophthalmic application as an immunosuppressive agent were studied over 6 months of storage at 4, 25 and 40 degrees C in different experimental conditions. The physical stability of nanospheres was followed by the study of morphological (visual appearance) and morphometrical properties (mean particle size and polydispersity). The pH and tonicity of the suspensions and the association efficiency of the drug to polymeric system were also analysed to evaluate their chemical stability. The behaviour of colloidal suspensions with storage conditions was also followed by differential scanning calorimetry. The degradation of PBCA was affected by temperature and pH. The average particle size of all nanospheres remained practically unchanged throughout the study, with the polydispersity index being less than 0.1, corresponding to a monodisperse system. At 40 degrees C, a loss of 25.9% of the initial association efficiency, especially in non-buffered pH 7.2 medium, was observed. The type of polymer degradation (surface erosion) was also determined by photon correlation spectroscopy. The results obtained from in vivo study of ocular tolerance indicate a good ocular tolerance for drug loaded to nanospheres.

Animals↗
PubMed2004

Effect of thermoultrasonication on Salmonella enterica serovar Enteritidis in distilled water and intact shell eggs.

The combined effects of simultaneous application of ultrasonic waves and heat treatment (thermoultrasonication) on the survival of a strain of Salmonella enterica Enteritidis was studied in both distilled water and intentionally contaminated intact eggs immersed in water. Although minor differences were observed between parameters obtained for thermoultrasonic treatment of bacteria suspended in water and those attached to the shell egg, the thermoultrasonication effects were considered to be of the same level in the range of temperatures assayed (52 to 58 degrees C). This combined process presented a clearly higher killing effect than the heat treatment alone. It decreased the decimal reduction times (D-values) by 80 to 55%, respectively, in the range of temperatures for heat treatment when the organism was suspended in water, which means a 99.5% reduction (5D to >2D) of the original bacterial load versus a 90% reduction for the heat treatment alone. The practical implications of the phenomenon are discussed.

Animals↗
PubMed2003

Simultaneous detection of influenza A, B, and C viruses, respiratory syncytial virus, and adenoviruses in clinical samples by multiplex reverse transcription nested-PCR assay.

The clinical presentation of infections caused by the heterogeneous group of the respiratory viruses can be very similar. Thus, the implementation of virological assays that rapidly identify the most important viruses involved is of great interest. A new multiplex reverse transcription nested-polymerase chain reaction (RT-PCR) assay that is able to detect and type different respiratory viruses simultaneously is described. Primer sets were targeted to conserved regions of nucleoprotein genes of the influenza viruses, fusion protein genes of respiratory syncytial viruses (RSV), and hexon protein genes of adenoviruses. Individual influenza A, B, and C viruses, RSV (A and B), and a generic detection of the 48 serotypes of adenoviruses were identified and differentiated by the size of the PCR products. An internal amplification control was included in the reaction mixture to exclude false-negative results due to sample inhibitors and/or extraction failure. Detection levels of 0.1 and 0.01 TCID50 of influenza A and B viruses and 1-10 molecules of cloned amplified products of influenza C virus, RSV A and B, and adenovirus serotype 1 were achieved. The specificity was checked using specimens containing other respiratory viruses and no amplified products were detected in any case. A panel of 290 respiratory specimens from the 1999-2000 and 2000-2001 seasons was used to validate the assay. Accurately amplifying RNA from influenza and RSV prototype strains and DNA from all adenovirus serotypes demonstrates the use of this method for both laboratory routine diagnosis and surveillance of all these viruses.

Adenoviruses, Human↗
PubMed2000

Derivation of pharmacophore and CoMFA models for leukotriene D(4) receptor antagonists of the quinolinyl(bridged)aryl series.

The present work focuses on the study of the three-dimensional (3D) structural requirements for the leukotriene D(4) (LTD(4)) antagonistic activity of compounds having the basic quinolinyl(bridged)aryl framework. An approach combining pharmacophore mapping, molecule alignment, and CoMFA models was used to derive a hypothesis for a series of LTD(4) antagonists having the basic diaryl-bridged framework. In this compound series, the produced pharmacophore hypotheses have shown to yield molecule alignments suitable to derive valuable CoMFA models. Model selection focused on (1) obtention of coherent modeling results, (2) consistency with the available SAR data, and (3) ability to predict the activity of an independent set of congeneric molecules. This approach resulted in a combined pharmacophore and CoMFA model that can generally represent the antagonistic activity within a log unit of the measured value for compounds of the series. The resulting pharmacophore (model C) consists of an acidic or negative ionizable function (AC), a hydrogen-bond acceptor (HBA), and three hydrophobic regions (HY) and produces chemically meaningful alignments with the most active compounds of the series mapping the pharmacophore in a extended energetically favorable conformation.

Combinatorial Chemistry Techniques↗
PubMed2000

A fast one-step reverse transcription and polymerase chain reaction (RT-PCR) amplification procedure providing highly specific complementary DNA from plant virus RNA.

Reverse transcription and polymerase chain reaction (RT-PCR) are being used increasingly for detection and typing RNA viruses. For this purpose, metal block thermal cyclers (MBTC) are considered to provide higher DNA yield, whereas air thermal cyclers (ATC) allow PCR amplification in a much shorter time. A fast ATC protocol (0 s denaturation, 0 s annealing, and 4-8 s elongation) was developed to amplify genomic segments from two RNA viruses, which allowed increasing the number of cycles without a parallel increase of non-specific DNA fragments. Under these conditions, 80-90 cycles with the ATC provided a DNA yield close to that of a standard 40-cycles MBTC protocol in about half the time. The DNA synthesised by the new procedure was highly specific and could be cloned readily.

Citrus↗
PubMed2000

Training of obstetric nurses and HIV testing in pregnancy at a managed care organization.

The purpose of this study was to evaluate the effectiveness of an HIV Training Programme for obstetric nurses at a managed care organization. Nurses were trained to counsel pregnant women about the HIV antibody test according to the latest recommendations made by the US Public Health Service and the Texas legislature. Training improved the nurses' overall knowledge about the content of the programme and nurses were more likely to offer the HIV test to all pregnant women. Still, contrary to what was predicted, the nurses did not give more information to increase the knowledge pregnant women had about HIV infection, transmission and available treatments. However, pregnant women who received prenatal care after the nurses attended the programme were more likely to be tested than women who received prenatal care before the nurses were trained (96% versus 48%); in turn, the likelihood that high-risk women would be tested for HIV also increased (94% versus 60%). There was no evidence that mandatory testing with right of refusal would deter pregnant women from being tested for HIV. The increased rate of HIV testing was attributable to the providers asking their patients to be tested rather than on their patients' knowledge of its benefits.

Adult↗
PubMed2000

Detection and identification of human parainfluenza viruses 1, 2, 3, and 4 in clinical samples of pediatric patients by multiplex reverse transcription-PCR.

We describe a multiplex reverse transcription-PCR (m-RT-PCR) assay that is able to detect and differentiate all known human parainfluenza viruses (HPIVs). Serial dilution experiments with reference strains that compared cell culture isolation and m-RT-PCR showed sensitivities ranging from 0.0004 50% tissue culture infective dose (TCID(50)) for HPIV type 4B (HPIV-4B) to 32 TCID(50)s for HPIV-3. As few as 10 plasmids containing HPIV PCR products could be detected in all cases. When 201 nasopharyngeal aspirate specimens from pediatric patients hospitalized for lower respiratory illness were tested, m-RT-PCR assay detected 64 HPIVs (24 HPIV-3, 23 HPIV-1, 10 HPIV-4, and 7 HPIV-2), while only 42 of them (21 HPIV-1, 14 HPIV-3, 6 HPIV-2, and 1 HPIV-4 isolates) grew in cell culture. Our m-RT-PCR assay was more sensitive than either cell culture isolation or indirect immunofluorescence with monoclonal antibodies for the detection of HPIV infections. Also, HPIV-4 was more frequently detected than HPIV-2 in this study, suggesting that it may have been underestimated as a lower respiratory tract pathogen because of the insensitivity of cell culture.

Animals↗
PubMed2000

Analysis of antinociceptive effects of flurbiprofen enantiomers in a rat model of arthritic pain.

The potential antinociceptive effects of the S(+)- and R(-)-enantiomers of flurbiprofen (SFB and RFB, respectively) were investigated when given intravenously to rats using the pain-induced functional impairment model in the rat (PIFIR), an animal model of arthritic pain. Groups of 6 rats received either vehicle or the enantiomer in turn and antinociception was determined by evaluating the dose-response curves over time. Although SFB and RFB produced dose-dependent effects with similar efficacy (SFB: 277.4 +/- 29.9 au and RFB: 293.5 +/- 20.1 au), the R(-)-enantiomer was unable to produce any antinociceptive action when assessed at the same dose ranges as SFB. It was necessary to increase the dose of RFB by 100 times to produce similar antinociception. Accordingly, S(+)-flurbiprofen was 100-fold more potent (ED50 = 0.33 +/- 0.13 mg/kg) than its antipode R(-)-(ED50 = 30.0 +/- 1.7 mg/kg). SFB generated from metabolic inversion (> 1%) after i.v. dosage of RFB, as well as impurities of SFB present in RFB preparations, tend to confirm the hypothesis that the efficacy of RFB achieved at 100 mg/kg, similar to that observed with 1 mg/kg of SFB, is attributable to SFB.

Analgesics↗
PubMed1999

Flurbiprofen-loaded nanospheres: analysis of the matrix structure by thermal methods.

We report the preparation and evaluation of flurbiprofen loaded-poly-epsilon-caprolactone nanospheres obtained by solvent displacement method. Characterization by thermal methods, infrared spectroscopy and X-ray diffraction analysis can reveal the dispersion state of the drug inside the nanospheres. Such information predicts the stability of the particles and the drug release behaviour. The study has indicated the presence of a molecular dispersed system. In addition, construction of a phase diagram has allowed us to determine the drug/polymer ratios at which flurbiprofen has the highest entrapment efficiency.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1999

An inductively coupled plasma method for determination of cyclophosphamide loaded to polymeric systems.

A new method for the determination of cyclophosphamide content of polyalkylcyanoacrylate nanoparticles was developed. The analyses were carried out by inductively coupled plasma atomic emission spectrometry (ICP-AES) by measuring the phosphorus content in the drug. The results obtained by this non-selective technique were compared with those given by high performance liquid chromatography (HPLC) a selective procedure that permits the detection of the cyclophosphamide molecule, and its degradation products. Sensitivity and reproducibility of both procedures were also determined. The ICP-AES method was demonstrated to be valid for sensitivity, precision, accuracy and specificity. In spite of ICP method is not a suitable procedure to analyze the degradation products of cyclophosphamide, the sensitivity of ICP is higher than chromatographic technique. Nevertheless, both procedures are appropriate for the determination of cyclophosphamide-loaded nanoparticles.

Antineoplastic Agents, Alkylating↗