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Biomedical subjects

H Santana

Publications and source records attributed to H Santana.

15 recordsLinked to original sources
PubMed2001

Relation between body composition, fat distribution, and lung function in elderly men.

BACKGROUND: Body composition changes with age, with increases in fat mass and visceral fat and declines in skeletal muscle mass; lung function also declines with age. Age-related changes in body composition and fat distribution may be associated with the pulmonary impairment observed in the elderly. OBJECTIVE: Our goal was to evaluate the relations between body composition, fat distribution, and lung function in elderly men. DESIGN: We studied 97 men aged 67-78 y with body mass indexes (BMIs; in kg/m2) ranging from 19.8 to 37.1. Body composition was evaluated by using dual-energy X-ray absorptiometry and fat distribution was evaluated by using waist and hip circumferences, waist-to-hip ratio, and sagittal abdominal diameter (SAD). Spirometry was done in all subjects and the distance walked by each subject during a 6-min walking test was evaluated as was leg strength. RESULTS: A significant negative correlation was found between adiposity, fat distribution indexes, forced vital capacity (FVC), and forced expiratory volume in 1 s (FEV1). A positive correlation was found between fat-free mass and FVC. After adjustment for age, height, and weight, SAD still correlated negatively with FVC and FEV1 (r = -0.367 and -0.348, respectively; P < 0.01), whereas percentage body fat and fat mass correlated negatively and fat-free mass correlated positively with FVC (r = -0.313, -0.323, and 0.299, respectively; all P < 0.01). After the sample was subdivided by tertile of fat-free mass adjusted for age and BMI, FVC and FEV1 were significantly lower in the lowest fat-free mass tertile (P < 0.01). Stepwise multiple regression analysis performed with use of lung function variables as the dependent variables and age, height, fat mass, fat-free mass, waist circumference, and SAD as the independent variables showed that 3 variables entered the regression for predicting FVC: height, which entered the regression first; SAD, which entered second; and fat-free mass, which entered third. Only 2 variables entered the regression for predicting FEV1: height, which entered the regression first, and SAD, which entered second. CONCLUSION: Our cross-sectional data show a significant association between body composition, fat distribution, and lung function in elderly men.

Absorptiometry, Photon↗
PubMed1999

Mice immunization with gel electrophoresis-micropurified bacterial lipopolysaccharides.

Some evidence on the possible use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) to elicit antibodies against smooth- or rough-type bacterial lipopolysaccharides (LPS) is shown. Gel-separated LPS were negatively stained with zinc-imidazole to precisely localize the bands of interest under fully reversible conditions. Then the bands of interest were excised and the resulting gel slices washed in a solution of a zinc-complexing agent (e.g., 100 mM EDTA), after which they were extruded through a metal sieve of 32 microm average size contained in a 1 mL syringe, to generate homogeneous gel microparticles. The LPS-containing gel slurries were used directly to immunize female BALB/c mice. Using this procedure, positive mouse polyclonal antibody responses against gel-purified smooth- or rough-LPS forms from Escherichia coli K-235 or Bordetella pertussis were elicited, as tested by a dot-immunoblotting assay. Our results may encourage the use of SDS-PAGE-micropurified LPS to develop optimized immunization procedures for the generation of specific antibodies against LPS bands of defined sizes, and therefore they constitute an intermediate step toward that aim.

Animals↗
PubMed1999

The relationship between body composition and physical performance in older women.

BACKGROUND: The relationship between age-associated change in body composition and physical disability is still unknown. Skeletal muscle mass declines with age in both sexes; however, since women have less muscle mass per unit of weight than men, these changes may be more debilitating in women. OBJECTIVE: To evaluate the relationship between body composition and physical performance. DESIGN: A cross-sectional study. PARTICIPANTS: 144 women aged 68 to 75 were selected randomly from the general population of Verona. MEASUREMENTS: Body composition was evaluated using dual energy X-ray absorptiometry and bioimpedance. Physical performance was evaluated using a modified version of the Activities of Daily Living scale. Distance walked in 6 minutes was calculated, and isometric knee strength was tested. RESULTS: Normal women had a significantly lower body mass index (BMI) and percent body fat. These women also had a higher ratio of body cell mass (BCM) and total fat free mass (FFM) than women with physical impairments. After adjusting for BMI, women in the lowest tertile of muscle strength had significantly lower BCM than those in the highest tertile. CONCLUSIONS: These cross-sectional data show that although muscle strength is related to fat-free mass, disability in older women is associated with heavier BMI and with a higher percentage of body fat.

Absorptiometry, Photon↗
PubMed1998

Elimination of an HuIFN alpha 2b readthrough species, produced in Escherichia coli, by replacing its natural translational stop signal.

When human interferon-alpha 2b (HuIFN alpha 2b) was expressed intracellularly in Escherichia coli as insoluble aggregates, a HuIFN alpha 2b molecular species of high molecular weight was detected, even after immunoaffinity chromatography and characterized by mass spectrometry and automatic sequencing. This HuIFN alpha 2b species was synthesized by an inefficient reading of the UGA natural stop codon, stopping the translation at another UGA in frame placed 10 codons downstream of the HuIFN alpha 2b stop signal. To avoid this translational readthrough process the UGA termination codon was replaced by UAA, which is frequently used in highly expressed E. coli genes. Simultaneously, almost all the HuIFN alpha 2b gene 3' noncoding region was removed. Analysis by SDS-PAGE and enzyme-linked immunosorbent assay revealed the elimination of the undesired HuIFN alpha 2b molecular species and an almost twofold increase in the expression level. These results indicate that both factors, the stop codon used and the length of the transcription unit should be taken into account when the expression in E. coli of heterologous proteins is desired.

Base Sequence↗
PubMed1998

Elution of lipopolysaccharides from polyacrylamide gels.

A simple procedure for elution in water of bacterial lipopolysaccharides (LPS) from sodium dodecyl sulfate-polyacrylamide gels is described. It consists of the combination of three principal steps: first, highly sensitive on-gel LPS detection (1-10 ng/band) with zinc-imidazole (negative or reverse staining); second, washing of the individual LPS band in a solution of a zinc-complexing agent (e.g., 100 mM EDTA); and finally, elution of the LPS (100-200 microliters water for a 0.5-microgram LPS band) from gel microparticles for 3 h at room temperature. Using this procedure, we have successfully eluted a variety of LPS forms from Bordetella pertussis, Escherichia coli 0111:B4, E. coli K-235, Salmonella enteritidis, and Pseudomonas aeruginosa. Elution recovery of rough or semismooth LPS was about 70-80%, while that of smooth LPS was only about 10%. Eluted LPS was biologically active as tested by limulus amebocyte lysate and TNF-alpha assays.

Acrylic Resins↗
PubMed1998

Sagittal abdominal diameter as a practical predictor of visceral fat.

OBJECTIVE: To evaluate the relationships between the supine sagittal abdominal diameter (SAD) and visceral fat, as well as to evaluate intra- and inter-observer reliability of sagittal diameter measurement. PATIENTS: Twenty-eight women ranging in age from 27-78 y with a body mass index (BMI) ranging from 16.9-48.1 kg/m2 and 23 men ranging in age from 32-75 y with BMI ranging from 20-41.6 kg/m2. MEASUREMENT: Body fat distribution was measured by waist circumference, waist to hip ratio (WHR), SAD, anthropometrically assessed and a single slice of computed tomography (CT) at the L4-L5 level. RESULTS: In both genders, a significant association was found between visceral adipose tissue (AT) and SAD, as evaluated by CT (women r = 0.80; men r = 0.83, P < 0.001), and SAD by anthropometry (women r = 0.76; men r = 0.82, P < 0.001), as well as between visceral AT and waist circumference (women r = 0.76, men r = 0.86, P < 0.001) and WHR (women r = 0.57, P < 0.01, men r = 0.80, P < 0.001). A significant association was also found between subcutaneous AT and SAD by anthropometry (women r = 0.79, men r = 0.74, P < 0.001). After adjusting for BMI, the association between subcutaneous AT and SAD was no longer significant in men and only moderately significant in women (r = 0.42, P < 0.05), while the association between visceral AT and SAD by anthropometry remained significant in both genders (women r = 0.63, P < 0.001; men r = 0.66, P < 0.001). When the subjects were divided into two groups according to BMI (lean to moderately overweight women with BMI < 28 and men with BMI < 30 and obese women with BMI > 28 and men with BMI > 30) we found that the relationships between SAD by anthropometry, as well as SAD by CT and visceral AT, were higher in lean to moderately overweight subjects than in those who were obese. High inter-observer correlation was found concerning SAD measurement (r = 0.99, P < 0.001). Intra- and inter-observer precision as evaluated by coefficient of variation and intraclass correlation coefficient for SAD measurement was very high. CONCLUSION: Our study shows the usefulness of SAD by anthropometry to predict visceral fat and its very high inter- and intra-observer precision.

Abdomen↗
PubMed1997

High yield elution of proteins from sodium dodecyl sulfate-polyacrylamide gels at the low-picomole level. Application to N-terminal sequencing of a scarce protein and to in-solution biological activity analysis of on-gel renatured proteins.

A simple, reliable procedure for practically quantitative (90-98%) and fast (< 30 min) elution of proteins from SDS-PA gels is described with reproducible recoveries in the range from 100 to 1 pmol per band, which does not require the inclusion of detergents in the elution buffer. It consists in the combination of (1) highly sensitive on-gel protein detection (50 mol per band) with imidazole-SDS-zinc (reverse staining), (2) crushing of the protein band to produce 32-micron gel particles, and (3) vortexing of the slurry in a solution of a zinc-complexing agent, e.g. glycine 0.5 M or EDTA 100 mM (100 microliters for a 100-pmol BSA band), at room temperature. Eluted proteins can be directly analyzed by RP-HPLC, quantitatively loaded onto a PVDF membrane, or, provided that they are previously renatured on-gel, analyzed by biological activity tests. The application of the procedure to in-solution enrichment of scarce proteins for N-terminal analysis is shown.

Acrylic Resins↗
PubMed1996

Role of endogenous polyamines in the proliferation of normal hematopoietic progenitor cells: high-proliferative potential colony-forming cells (HPP-CFC), and low-proliferative potential colony-forming cells (LPP-CFC). Studies "in vitro".

This study concerns the role of endogenous polyamines in the proliferation of normal hematopoietic progenitor cells: high-proliferative potential colony-forming cells (HPP-CFC), and low-proliferative potential colony-forming cells (LPP-CFC) in CFW/ep mouse bone marrow cells in the agar culture system. DL-a-difluoromethylornithine (DFMO) was used as a selective and irreversible inhibitor of ornithine decarboxylase which is the first limiting step in polyamine biosynthesis. The polyamines have been implicated in cell proliferation and differentiation. The results showed that DFMO significantly inhibited the formation of LPP-CFC colonies and completely inhibited the growth of the HPP-CFC colonies. Addition of exogenous putrescine at the concentration of 10(-7) M reverses the suppressive action of DFMO in both progenitor cells. At this concentration putrescine alone had no affect on the number or the size of the colonies. It was then concluded that endogenous polyamines appear to be essential for HPP-CFC proliferation and an important requirement for LPP-CFC proliferation.

Animals↗
PubMed1992

Purification of immunoprecipitated pemphigus foliaceus antigen fragment and its use in radioimmunoassay.

A major difficulty in biochemical studies of the pemphigus foliaceus (PF) antigen is the lack of a method for its quantitative determination. Immunofluorescence blocking and immunoprecipitation methods are semiquantitative and time consuming. Radioimmunoassay (RIA) methods are quantitative but they require pure and stable antigen preparations that have not been available for PF. The present investigation shows the further purification of a previously described preparation of PF antigen fragment obtained from trypsinization media of mouse skin (Con A Frn) and demonstrates its usefulness in a RIA method for quantitation of the antigen. The major contaminants of the 45-kD tryptic fragment of the PF antigen (tf-PF) in immunoprecipitates of the Con A Frn with PF sera were identified as H and L chains of murine IgG and mannose-binding lectins. The IgG contaminants could be removed by avoidance of blood contamination during preparation of the Con A Frn and/or pre-absorption of the Con A Frn with protein A Sepharose. The lectins could be removed by affinity chromatography of the Con A Frn on asialofetuin column and washing the immunoprecipitates with 0.2 M alpha-methyl-mannoside. Using the purified, labeled Con A Frn in RIA, we showed that standard curves could be established and the amounts of PF antigen could be determined in different extracts without the need for electrophoresis, autoradiography, or scanning. This RIA method is rapid and can be easily used to analyze many samples, e.g., chromatographic fractions and extracts made from different tissues.

Animals↗
PubMed1984

Specific keratins as molecular markers for neoplasms with a stratified epithelial origin.

The expression of specific keratin polypeptides in human neoplasms was investigated by the immunoblot technique using monoclonal anti-keratin antibodies. Mr 50,000 and 58,000 keratins, recognized by AE1 and AE3 antibodies, respectively, were detected only in carcinomas of stratified epithelial origin, but not in carcinomas derived from simple epithelia. No keratin was detected in nonepithelial tumors including melanoma, lymphoma, neurofibroma, and sarcoma. The results suggest that the Mr 50,000 and 58,000 keratins provide useful molecular markers for identifying neoplasms of stratified squamous epithelial origin.

Antibodies, Monoclonal↗
PubMedDate not supplied

[Obtaining antibodies and development of an immunoassay for the detection of Escherichia coli proteins in preparations of human recombinant gamma interferon].

The present paper refers to the obtainment of polyspecific antisera directed against Escherichia coli host strain used to produce recombinant human gamma interferon (rec. hum. gamma IFN). The antisera were obtained by the cascade immunization method. The animals (n = 3) were initially immunized with an E. coli protein preparation (EcPp) of the host strain obtained from a blank run which assures the absence of the rec. hum. gamma IFN protein. Afterwards, consecutive immunizations were carried out with the less immunogenic proteins. To obtain those proteins, EcPp is passed through a column containing antibodies purified from previous inoculations coupled to a gel matrix. In this way, the proteins that have not been recognized by the immune system in that moment (e.g. do not have their corresponding antibodies coupled to the column) are separated an used to reimmunize the animals. The analyses of the antisera by Western blotting show a progressive recognition of the host strain proteins by the antisera with the progression of the cascade method. The recognition is evident through all the molecular weight range. Those antisera were used as quality control of the recombinant protein, by quantification of the host strain protein contaminants using a multiantigenic ELISA. The detection limit of that system was 3.125 ng/mL and the quantification limit 6.25 ng/mL.

Animals↗