Biomedical subjects

Sonia González

Publications and source records attributed to Sonia González.

12 recordsLinked to original sources

PubMed2006

Food intake and serum selenium concentration in elderly people.

BACKGROUND/AIMS: It is becoming apparent that the essential trace element selenium plays a critical role in the maintenance of optimal health status. The objective of this study was to identify the food groups that most contributed to selenium intake and its serum levels in elderly people. METHODS: Dietary intake was assessed in 205 institutionalized elderly by means of a 1-year food frequency questionnaire (FFQ). Intake of macronutrients and minerals of the diet were estimated. Selenium was determined in serum and analyzed by graphite-furnace atomic absorption spectrometry. RESULTS: Selenium intake and serum concentration were both within the normal range. The major contributors to selenium intake were cereals and bakery, fish and shellfish, meat and meat products and dairy products. All of them except cereals were also associated to serum selenium. Intake of animal protein, but not the vegetable one, contributed to serum selenium. CONCLUSION: An adequate intake of fish and meat would be of importance to improve selenium status and health principally in elderly people who are at high risk of mineral deficiency.

Aged↗

PubMed2006

Lipid peroxidation, antioxidant status and survival in institutionalised elderly: a five-year longitudinal study.

Oxidative stress has been related to ageing and risk of death. To determine whether oxidative status was associated with all-cause risk of death we carried out a prospective study in 154 non-smoking Spanish elderly without major illness. Baseline glutathione peroxidase (GPx) and superoxide dismutase (SOD) were analysed in plasma and erythrocytes. alpha-tocopherol, beta-carotene, lycopene and retinol were determined in serum samples and malondialdehyde (MDA), as a lipid peroxidation marker, in plasma. Mean survival time was 4.3 years. A total of 31 death cases (20.1%) occurred during the follow-up. Plasma-MDA predicted mortality independently of all other variables, while erythrocyte-SOD (e-SOD), beta-carotene and alpha-tocopherol were positively associated with survival. alpha-tocopherol and MDA were revealed as independent predictors in a joint survival model, being the group with low MDA and high alpha-tocopherol that with the lowest mortality. In conclusion, a higher risk of death was associated with increased lipid peroxidation and lower antioxidant defenses.

Aged↗

PubMed2005

Immunization with Neisseria meningitidis outer membrane vesicles prevents bacteremia in neonatal mice.

Although vaccines based on outer membrane vesicles (OMV) of Neisseria meningitidis have been developed and administered to children, little is known about the magnitude and quality of the immune response in animal models of early life immunization. We investigated the immunogenicity of meningococcal OMV, and the influence of route and immunization schedule, in neonatal mice. The administration of two intraperitoneal doses of OMV, given at 7 and 14 days after birth, induced a significant antibody response and was highly effective in conferring protection against bacteremia in 21-day-old mice challenged with meningococci. Intranasal immunization was less effective and did not generate a protective immune response. The antibodies elicited by intraperitoneal immunization were cross-reactive with several meningococcal strains and a memory response was demonstrated when mice immunized as neonates were given a booster immunization at 6 weeks of age.

Administration, Intranasal↗

PubMed2005

Comparison of three ELISA protocols to measure antibody responses elicited against serogroup C meningococcal polysaccharide in mouse, monkey and human sera.

In this study we compared the following ELISA protocols to measure antibody levels against serogroup C meningococcal polysaccharide: a traditional protocol using poly-L-Lysine mixed with the polysaccharide as coating antigen, a second protocol coating with a mixture of methylated human serum albumin with the C polysaccharide, a modified protocol coating with derivatized polysaccharide and a modification to the last one, specifically without adding ammonium thiocyanate to the sample buffer. Serum bactericidal activity of mouse, monkey and human sera were measured and correlation coefficients were calculated. For all serum types the modified ELISA protocol showed the highest correlation coefficients while the traditional protocol showed the lower ones. We demonstrated that the traditional protocol measures non-specific antibodies to the C polysaccharide, because no differences were detected between pre-immune and post-immune human sera (P>0.05), while the modified protocol detected the highest difference (P<0.01).

Animals↗

PubMed2005

Phase II and tumor pharmacodynamic study of gefitinib in patients with advanced breast cancer.

PURPOSE: To evaluate the antitumor activity and pharmacodynamic/biologic effect of gefitinib 500 mg/day monotherapy in patients with previously treated, advanced breast cancer. METHODS: In this phase II multicenter trial, the primary objective was assessment of the tumor response rate with gefitinib; secondary objectives included analysis of the pharmacodynamic and biologic profiles in healthy and tumor tissue. RESULTS: while phosphorylation of mitogen-activated protein kinase was inhibited in both tissues, gefitinib treatment induced p27 and a decrease in Ki67 in skin but not in tumors. Furthermore, gefitinib did not inhibit the activated form of Akt in the tumors. CONCLUSION: This study demonstrates a good correlation between the degree of inhibition of EGFR in skin and in breast tumors. The lack of significant clinical activity of gefitinib in our study population is not due to lack of receptor inhibition in these tumors but rather to lack of EGFR dependence in the tested population.

Adult↗

PubMed2004

Cell mediated immune response elicited in mice after immunization with the P64k meningococcal protein: epitope mapping.

The P64k protein of Neisseria meningitidis has been reported as an immunological carrier for weak immunogens. This investigation was aimed at characterizing the T-cell response produced in primed mice and at identifying T helper cell epitopes within this molecule. BALB/c mice subcutaneously immunized with the recombinant antigen provided inguinal lymph node cells (LNC) that proliferated in the presence of P64k in a dose-dependent manner. Proliferating cells secreted IL-4 while the concentration of IL-12 remained unaltered in the culture supernatant. By testing a panel of 59 overlapping synthetic peptides spanning the entire sequence of the antigen a T-cell determinant was localized. Prime-boost and lymphoproliferation experiments, conducted with highly purified synthetic peptides, confirmed that the segment including amino acids 470-485 comprises a T-cell epitope within the P64k molecule.

Amino Acid Sequence↗

PubMed2004

Effect of conjugation methodology on the immunogenicity and protective efficacy of meningococcal group C polysaccharide-P64k protein conjugates.

Neisseria meningitidis serogroup C polysaccharide (CCPS) was conjugated to the carrier protein P64k using two different conjugation procedures, condensation mediated by carbodiimide with adipic acid dihydrazide as spacer and the reductive amination method. BALB/c mice were immunized with the resultant polysaccharide-protein conjugates and the immune response was evaluated. All conjugates assayed generated at least 10-fold higher antibody titers than the free polysaccharide. The reductive amination method rendered the best conjugate (CCPS-P64kR) that was able to elicit antibody titers statistically higher than the titer elicited by the plain CCPS (P<0.001). The sera of the group immunized with CCPS-P64kR showed a three-fold higher bactericidal response than the sera of the group immunized with the plain CCPS and they were able to protect against challenge with meningococci in the infant rat protection model. In addition, three different conjugates were obtained from polysaccharides with molecular relative sizes of 2000-4000 Da, 4000-10,000 Da or 10,000-50,000 Da, but no differences were detected in the immune response obtained against the three conjugates. Our experiments demonstrate that it is possible to generate a protective, T-cell-dependent response against CCPS using the P64k protein as carrier.

Adipates↗

PubMed2004

Parkinson's Disease Sleep Scale: validation study of a Spanish version.

The Parkinson's Disease Sleep Scale (PDSS) is the first published bedside clinical tool to specifically measure sleep disturbances in Parkinson's disease (PD). The objective of the present study was to carry out a metric analysis of a Spanish version (PDSS-SV) using a cross-sectional study of 100 PD patients who participated in the study. Usual measures for PD and mental status were applied by neurologists. Patients completed the Epworth Sleepiness Scale, Parkinson's Disease Questionnaire-39 Items (PDQ-39), and PDSS-SV. PDSS internal consistency (Cronbach's alpha, 0.77; significant item-total correlation for 11 items) was satisfactory. PDSS showed high test-retest reliability (intraclass correlation coefficient for items, 0.79-0.99; for total score, 0.94). Standard error of measurement was 9.80 (crossover) and 5.01 (longitudinal). Scores were distributed uniformly, with low floor and ceiling effect (1%). PDSS scores were correlated significantly with depression (Hamilton Depression Rating Scale, r(S) = -0.55; P < 0.0001) and quality of life (PDQ-39 Summary Index, r(S) = -0.26; P = 0.007), but not with clinical variables. Self-perception of mood disorder, pain, or hallucinations correlated individually with PDSS scores, and a factor explaining 65% of the variance was found. The assessment of PD sleep disorders with the PDSS met some basic standards required for health status measures.

Cross-Sectional Studies↗

PubMed2004

Folate and cobalamin synergistically decrease the risk of high plasma homocysteine in a nonsupplemented elderly institutionalized population.

OBJECTIVE: Total plasma homocysteine (tHcy) has been associated with an increased risk of cardiovascular disease in the general population and elderly subjects are at high risk of elevated homocysteine because of an impaired vitamin status. The aim of the present study was to determine the independent and interactive association of adequate folate and cobalamin (intake and serum levels) with tHcy in elderly subjects who were not taking vitamin supplementation. DESIGN AND METHODS: Cross-sectional analysis of a sample of 140 elderly recruited from seven nursing homes in Asturias (Northern Spain). Dietary intake was assessed by a food frequency questionnaire, and serum folate, cobalamin, and tHcy were determined in fasting blood samples. RESULTS: Mean tHcy concentration was 13.3 micromol/L (upper quartile of tHcy >16.0 micromol/L) and was inversely correlated with serum folate. Subjects with an adequate intake or serum levels of both folate and B12 were at a reduced risk of being in the highest quartile of tHcy. In both cases, the reduction of high tHcy (upper quartile) risk was found to be greater than expected when subjects with high levels of both vitamins were considered together. CONCLUSIONS: Adequate folate and cobalamin (both intake and serum levels) act synergistically to decrease the risk of high total plasma homocysteine levels in this elderly population.

Aged↗

PubMed2004

No evidence for oxidative stress as a mechanism of action of hyperhomocysteinemia in humans.

Oxidative stress has been suggested as one of the physiopathologic conditions underlying the association of total plasma homocysteine (p-tHcy) with cardiovascular disease (CVD), but this hypothesis has not been validated in human epidemiological studies. We measured plasma and erythrocyte antioxidant enzymes glutathione peroxidase (GPx) and superoxide dismutase (SOD), along with serum lipid-soluble antioxidants alpha-tocopherol, beta-carotene, lycopene and retinol, in a sample of 123 healthy elderly subjects (54 men, 69 women). Plasma malondialdehyde (p-MDA) was determined as a marker of lipid peroxidation, and p-tHcy was quantified by HPLC. No significant differences were found for p-MDA, GPx or SOD activities or serum antioxidant concentrations, in subjects with elevated p-tHcy (> or =15 micromol/l) as compared to those with lower plasma homocysteine. Hyperhomocysteinemia did not lead to increased risk of having the highest p-MDA values, in either sex. We found no evidence that p-tHcy was associated with lipid peroxidation in this elderly human sample. Our results do not support the view that hyperhomocysteinemia would induce an adaptive response of antioxidant systems, either. More epidemiologic and clinical research is needed to clarify whether homocysteine promotes atherosclerosis by means of an oxidative stress mechanism.

Aged↗

PubMed2004

Serum selenium is associated with plasma homocysteine concentrations in elderly humans.

Low selenium levels in humans have been associated with several pathologies; however, an earlier animal investigation found a direct association between Se intake and total plasma homocysteine (tHcy) concentrations. To date, the importance of serum selenium levels in association with tHcy in humans has not been determined. We evaluated the cross-sectional association of blood selenium concentrations with plasma tHcy and other determinants of this cardiovascular disease risk factor. We estimated protein intake and measured the blood status of selenium, tHcy, and several other related factors in serum such as folate, vitamin B-12, and creatinine. Serum selenium was inversely associated with tHcy, explaining 5.8% of tHcy variance with respect to 2.2% accounted for by serum folate. Furthermore, there was a 63% decreased risk of higher tHcy concentrations (>14 micro mol/L) for subjects with serum selenium in the highest tertile (P = 0.013). We also found an inverse association of protein intake with tHcy in men (beta = -0.144; P = 0.036), which disappeared after controlling for serum Se concentrations (beta = -0.055; P = 0.003). In conclusion, selenium should be considered as a potential factor to lower tHcy. In addition, the described association between protein intake and homocysteine levels could be mediated by this trace element.

Aged↗

PubMed2003

Plasma iron is associated with lipid peroxidation in an elderly population.

Epidemiological evidence has raised concern that a moderate elevation in body iron stores may increase oxidative stress and risk of heart disease. We examined the cross-sectional association between plasma iron and factors that could affect its levels (antioxidant enzymes, diet), with the concentration of plasma malondialdehyde (MDA) as a marker of lipid peroxidation. Participants were 162 non-smoking institutionalised elderly. Our results show that those in the highest tertile of plasma iron were at least twice as likely to have higher plasma MDA levels. Among the factors affecting plasma iron levels, we found that the upper tertile of erythrocyte-superoxide dismutase (E-SOD) was inversely associated with higher plasma iron, and potato intake explained a sizeable proportion of the variation in plasma iron levels. In addition to potatoes, eggs, wine, fruit in men and green vegetables in women showed a positive association with plasma iron levels. Only potatoes in both sexes, wine in men and eggs in women had an independent effect on plasma MDA. Potatoes, wine, plasma lycopene and plasma iron accounted for 43% of the variability in plasma MDA for males, and E-SOD, potatoes, eggs, plasma lycopene and plasma iron explained 45% for women. A longitudinal study should confirm, whether these MDA levels are related to morbidity and mortality.

Aged↗