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Biomedical subjects

M Aguirre

Publications and source records attributed to M Aguirre.

At least 19 recordsLinked to original sources
PubMed2006

High stability of yellow fever 17D-204 vaccine: a 12-year restrospective analysis of large-scale production.

We have retrospectively analyzed 12 bulk lots of yellow fever vaccine Stamaril, produced between 1990 and 2002 and prepared from the same seed lot that has been in continuous use since 1990. All vaccine batches displayed identical genome sequence. Only four nucleotide substitutions were observed, compared to previously published sequence, with no incidence at amino-acid level. Fine analysis of viral plaque size distribution was used as an additional marker for genetic stability and demonstrated a remarkable homogeneity of the viral population. The total virus load, measured by qRT-PCR, was also homogeneous pointing out reproducibility of the vaccine production process. Mice inoculated intracerebrally with the different bulks exhibited a similar average survival time, and ratio between in vitro potency and mouse LD(50) titers remained constant from batch-to-batch. Taken together, these data demonstrate the genetic stability of the strain at mass production level over a period of 12 years and reinforce the generally admitted idea of the safety of YF17D-based vaccines.

Animals↗
PubMed2006

Extremity amniotic band syndrome in fetal lamb. I: An experimental model of limb amputation.

OBJECTIVE: The objective of the study was to reproduce severe forms of extremity amniotic bands, which result in amputation or severe lesions. STUDY DESIGN: Right limbs of 5 60-day gestational age pregnant sheep were ligated with silk suture at the infracondylar level. Left limbs were used for paired comparison. The limbs obtained from term fetuses were analyzed morphologically, radiologically, and histologically. RESULTS: The ligated limbs showed an amputation or quasiamputation. Four extremities showed a necrotic pattern and 4 an edema pattern. CONCLUSION: A model of severe extremity amniotic bands that reproduces the effect of the extremity amniotic bands in the human fetus was developed. Future applications of this new model could be an experimental study of in utero salvage of limbs affected with severe extremity amniotic bands in the ovine fetus.

Amniotic Band Syndrome↗
PubMed2001

Quantification in mass units of group 1 grass allergens by a monoclonal antibody-based sandwich ELISA.

BACKGROUND: Grass pollen extracts currently used for allergy diagnosis and immunotherapy are a complex mixture of proteins of which only a few have allergenic activity. Lol p 1 is one of the most important allergens in grass pollen extracts. OBJECTIVES: To develop a two-site enzyme-linked immunosorbent assay for the quantification of Lol p 1 and other group 1 allergens from grass species, and to assess its suitability for quantifying this group of allergens. METHODS: Balb/c mice immunized with recombinant Lol p 1 were used for the production of monoclonal antibodies. Screening of hybridomas was performed by direct ELISA, and selected monoclonal antibodies were immobilized on ELISA plates and incubated with samples containing group 1 allergens. Bound allergens were detected by a combination of biotinylated Lol p 1-specific monoclonal antibody and peroxidase-streptavidin conjugate. RESULTS: The assay is based on three Lol p 1-specific monoclonal antibodies with different epitope specificities. The optimized ELISA measured Lol p 1 concentrations ranging from 125 to 1000 ng/mL and could quantify group 1 allergen from grass species belonging to the Pooidea subfamily. The assay does not depend on anti-sera production or availability of human sera and thus reactives can be produced in unlimited amounts. CONCLUSION: This sensitive and specific Lol p 1 assay will be helpful both for quantifying the group 1 allergen content of Pooideae pollen extracts intended for clinical use and for studying cross-reactivities among pollen extracts.

Allergens↗
PubMed2001

Injury severity and sensitivity to treatment after controlled cortical impact in rats.

We sought to determine sensitivity of the cortical impact injury model of traumatic brain injury (TBI) to severity of injury and to treatment. We examined the pattern of motor and cognitive deficits and recovery following TBI over a range of injury severities, and examined the efficacy of surface-induced moderate hypothermia at three disparate injury levels. In experiment I, Sprague-Dawley rats were injured at one of eight injury severity levels from 0 mm (sham) to 2.5 mm depth of penetration. On postinjury day 1, balance beam, rotorod performance, and posture reflexes were evaluated. Motor outcome was increasingly impaired with increasing injury levels, with the pattern of deficits showing a step-like function. Cognitive deficits, assessed using water maze on day 7, were more severe for the 2.5-mm group than for the 1.6-mm injury group, while the 1.0-mm group did not differ from the sham controls. In experiments II-IV, hypothermia, 30 degrees C for 3-h duration or normothermia was applied to three injury levels: 1.0 mm, the least cortical deformation; 2.5 mm, the most deformation; and 1.6 mm, representing a level in-between. Neurologic outcome was assessed relative to shams on postinjury days 1, 3, and 5. The 1.0-mm group exhibited small deficits that recovered completely by day 3; the 1.6-mm group recovered to the level of shams by day 5, and the 2.5-mm group did not show significant recovery during the testing period. Hypothermia effectively attenuated behavioral deficits for the 1.6-mm group, but had no effect on the other two groups. These three observations--that increasing injury severity is associated with increasing motor and cognitive deficits, that injury severity is related to recovery time, and that hypothermia treatment is selectively effective--have each been reported in the human TBI population; thus, moderate cortical impact injury in rats may be a model with clinical predictability for evaluating neuroprotective therapies.

Animals↗
PubMed1999

Quantification of profilins by a monoclonal antibody-based sandwich ELISA.

Profilins are plant allergens responsible for cross-reactivities in pollen and fruit-allergic patients. A two-site enzyme-linked immunosorbent assay has been developed for the quantification of profilins and its suitability for quantifying profilin in different plant extracts has been evaluated. The assay is based on two profilin-specific monoclonal antibodies (mAbs) with different epitope specificities. These antibodies were immobilized on ELISA plates and incubated with samples containing profilin. Bound profilin was detected by a combination of biotinylated profilin-specific antiserum and peroxidase-streptavidin conjugate. The optimized ELISA measured profilin concentrations ranging from 4 to 250 ng/ml and could quantify profilins from plant species of a variety of different botanical families. No reactivity to mites, molds, or crustaceans was detected, suggesting that the immunoassay is plant-specific. The results indicate that this sensitive profilin-assay will be helpful both for quantifying the profilin content of allergenic extracts intended for clinical use and for studying cross-reactivities between pollen extracts.

Allergens↗
PubMed1998

Enhanced vasorelaxation by overexpression of beta 2-adrenergic receptors in large arteries.

This study was designed to determine if adenoviral-mediated delivery of a transgene encoding the beta 2-adrenergic receptor (beta 2-AR) to the carotid arterial wall could result in alterations in in vivo vascular function. De-endothelialized rat carotid arteries were infused in vivo with 0.1 mg/ml elastase and adenovirus [6 x 10(9) plaque forming units (PFU)] containing either the marker gene beta-galactosidase (Adeno-beta-gal), DNA encoding the human beta 2-AR (Adeno-beta 2-AR), or no transgene. This low concentration of elastase increased the water permeability (5.2 +/- 0.6 v 1.9 +/- 0.4 x 10(-8) cm/s/mmHg, n = 4, P < 0.0001) without affecting either the vasomotor responsiveness or the morphology of the arterial wall. A transfection efficiency of 73% was achieved with Adeno-beta-gal (n = 3). beta-gal expression was associated with infrequent appearance of T and B lymphocytes, or neutrophil infiltration. Five days after infection with Adeno-beta 2-AR, the total beta-AR density increased six-fold (67.8 +/- 3.4 v 397.0 +/- 155.5 fmol/mg protein, n = 5, P < 0.01); isoproterenol-induced vasorelaxation at transmural pressures from 10-110/mmHg increased (P < 0.01) compared to arteries exposed to control virus (empty adenovirus), n = 4; and isoproterenol-stimulated cAMP production was increased by 65% (n = 5). Thus, adenoviral-mediated delivery of beta 2-ARs into large artery walls results in enhanced beta-AR-mediated vasorelaxation via augmentation in cAMP levels in vascular smooth muscle cells.

Adenoviridae↗
PubMed1998

Cloning and immunological characterization of the allergen Hel a 2 (profilin) from sunflower pollen.

Sunflower (Helianthus annuus) sensitization is not always related with occupational allergy. We have isolated the allergen profilin (Hel a 2) from this Compositae plant, cloned and sequenced five cDNAs encoding for full-length or partial Hel a 2. Natural sunflower profilin reacted with specific IgE in the 121 sera tested, at a frequency of 30.5%. Expression of the cDNA encoding Hel a 2 in Escherichia coli and a simple purification procedure by poly-L-proline chromatography allowed immunological characterization of the recombinant allergen. Binding of monoclonal antibodies against sunflower profilin revealed that some epitopes responsible for antigen-specific IgG production were not present in the recombinant allergen. High cross-reactivity has been found between recombinant Hel a 2 and profilins from other Compositae plants and also from botanically distant plants.

Allergens↗
PubMed1997

Cylindrical ultrasonic transducers for cardiac catheter ablation.

This study was designed to evaluate the feasibility of using cylindrical ultrasound transducers mounted on a catheter for the ablation of cardiac tissues. In addition, the effects of ultrasound frequency and power was evaluated both using computer simulations and in vitro experiments. Frequencies of 4.5, 6, and 10 MHz were selected based on the simulation studies and manufacturing feasibility. These transducers were mounted on the tip of 7-French catheters and applied in vitro to fresh ventricular canine endocardium, submerged in flowing degassed saline at 37 degree C. When the power was regulated to maintain transducer interface temperature at 90-100 degree C, the 10-, 6-, and 4.5-MHz transducers generated a lesion depth of 5.9 +/- 0.2 mm, 4.6 +/- 1.0 mm, and 5.3 +/- 0.9 mm, respectively. The 10-MHz transducer was chosen for the in vivo tests since the maximum lesion depth was achieved with the lowest power. Two dogs were anesthetized and sonications were performed in both the left and right ventricles. The 10-MHz cylindrical transducers caused an average lesion depth of 6.4 +/- 2.5 mm. In conclusion, the results show that cylindrical ultrasound transducers can be used for cardiac tissue ablation and that they may be able to produce deeper tissue necrosis than other methods currently in use.

Animals↗
PubMed1997

Invasive Nattrassia mangiferae infections: case report, literature review, and therapeutic and taxonomic appraisal.

We report on a case of subcutaneous infection of the arm caused by the coelomycetous fungus Nattrassia mangiferae (formerly Hendersonula toruloidea) in a steroid-dependent diabetic man with chronic obstructive lung disease. The man was a resident of Arizona, where the fungus is known to be endemic on Eucalyptus camaldulensis and on citrus trees. Diagnosis of fungal infection was made by observation of narrow hyphal filaments by histopathology of biopsy specimens and isolation of a fast-growing black mold which demonstrated hyphae and arthroconidia of varying widths typical of the Scytalidium synanamorph (S. dimidiatum). The formation of pycnidia, which at maturity expressed conidia with a central median dark band, allowed for the confirmation of the isolate as N. mangiferae. Remission of the lesions occurred following intravenous therapy with amphotericin B, followed by topical clotrimazole treatment. We use this patient's case report as an opportunity to review the literature on cases of deep infection caused by Scytalidium species, to evaluate the antifungal susceptibilities of a spectrum of Scytalidium isolates, and to review the taxonomy of Scytalidium species isolated from human infections.

Aged↗
PubMed1997

Bone mass and hip axis length in healthy Asian, black, Hispanic, and white American youths.

The primary objective of this study was to examine the associations of ethnicity, diet (calcium, protein, energy), and weight-bearing activity with dual-energy X-ray absorptiometry (DXA)-measured bone mass and hip axis length (HAL) in 423 Asians, blacks, Hispanics, and non-Hispanic Caucasians, aged 9-25 years. Bone mass was expressed as bone mineral content (BMC), bone mineral density (BMD), and bone mineral apparent density (BMAD). The data were analyzed using multiple linear regression, after stratifying for gender and pubertal stage and adjusting for height and weight. With few exceptions, Asians and Hispanics had comparable bone mass to whites at all pubertal stages. Greater femoral neck BMAD in black than white females was observed at all pubertal stages. Black males displayed greater BMD and BMAD than white males at all sites in early puberty and at the femoral neck in maturity. Calcium was positively and protein negatively related to BMAD at the femoral neck in early pubertal females. Among males, calcium was negatively associated with whole body BMC and BMD and spine BMD and BMAD in midpuberty. Weight-bearing activity was not associated with bone mass in females; in males, it was positively related only to femoral neck BMC in early puberty. There was an absence of evidence for ethnic differences in HAL among females. In males, we observed shorter HAL in mature Asians and blacks than whites. Neither diet nor activity was associated with HAL.

Absorptiometry, Photon↗
PubMed1997

Proliferative and maturative behaviour patterns on murine bone marrow and spleen erythropoiesis along hypoxia.

The present study was performed to determine quantitative and qualitative effects of hypoxia on murine erythron. CF1 mice were submitted to hypobaric hypoxia (HH) along 18 days. The proliferative response to recombinant human erythropoietin (rHuEPO: 0-250 mU/ml) was analyzed by DNA assays from bone marrow and spleen cells at different times. Bone marrow proliferative response showed a slight increment under stress but remained over control by the end of the experience. Splenic erythroid proliferative response was observed at a maximum rate on day 6 of HH (26 fold) and returned near to control values after day 10. The assessment of erythropoietic maturative pattern was performed by 59Fe uptake assays. Total nuclear cell counts increased in both tissues (1.5 times in marrow and 5 times in spleen) under hypoxia. In addition, percentages of different lineages (erythroid, myeloid and lymphoid) were scored. Total erythroid marrow cell counts increased in a narrowly degree and persisted above basal counts after day 18. Meanwhile, splenic red cells rose to 30 times over control on day 6 and failed sharply near control values from day 12 of HH. Splenic red cells contribution was approximately 60% of total production between 6-8 days. By the end of the assay bone marrow took back erythroid command (90%). These findings indicate correlation between the time course as well as quantitative and qualitative parameters in the patterns of proliferation and maturation. Moreover, the erythron response to hypoxia, seemed to be related to microenvironmental regulations rather than to hormonal variances.

Animals↗
PubMed1995

Analysis of K-ras gene mutations in malignant and nonmalignant endobronchial tissue obtained by fiberoptic bronchoscopy.

Using polymerase chain reaction DNA amplification, we identified K-ras oncogene mutations in bronchial biopsies obtained from patients undergoing bronchoscopy for clinical indications. We hypothesized that these mutations would be found in a field encompassing malignant and nonmalignant tissues in patients with pulmonary carcinomas, and also possibly in tissue from some patients who smoked but did not have pulmonary malignancy. We found K-ras mutations in endobronchial biopsies from nine of 22 patients (41%) with carcinoma of the lung. In five of these patients, mutations were found in both malignant and nonmalignant specimens. In two instances, mutations were found only in the neoplastic tissue, and in two cases mutations were present only in the nonmalignant tissue. Furthermore, we identified two patients with K-ras mutations among seven patients in whom no clinical malignancy was apparent. Our data suggest that some oncogene activations may occur over a broad area in smokers with and without malignancy, and they imply that K-ras mutations may serve as surrogate markers for malignant potential.

Aged↗
PubMed1993

Phenotypic and phylogenetic characterization of some Gemella-like organisms from human infections: description of Dolosigranulum pigrum gen. nov., sp. nov.

A phylogenetic analysis was performed on two previously uncharacterized Gram-positive, catalase-negative bacteria from clinical sources. 16S rRNA sequencing studies revealed the isolates represent a new line of descent within the lactic acid group of bacteria. On the basis of the phylogenetic findings and phenotypic distinctiveness of the organisms, it is proposed that they be classified in a new genus Dolosigranulum, as Dolosigranulum pigrum sp. nov. The type strain of Dolosigranulum pigrum is NCFB 2975.

Base Sequence↗
PubMed1993

Development of a polymerase chain reaction test for specific identification of the urinary tract pathogen Aerococcus urinae.

A polymerase chain reaction test was developed for identification of the gram-positive urinary tract pathogen Aerococcus urinae. Oligonucleotide primers were based on highly specific sequences within the small-subunit rRNA gene. A confirmatory test based on hybridization of the amplified products to a highly specific internal probe was also developed.

Bacteriological Techniques↗