Biomedical subjects

A Aparicio

Publications and source records attributed to A Aparicio.

At least 19 recordsLinked to original sources

PubMed2006

Changes in thiamin intake and blood levels in young, overweight/obese women following hypocaloric diets based on the increased relative consumption of cereals or vegetables.

OBJECTIVE: To analyse the changes in thiamin intake and blood levels of young, overweight/obese women following slightly hypocaloric diets based on the increased relative consumption of foods whose intakes were most removed from the ideal: cereals and vegetables. DESIGN: The women were randomly assigned to one of two slightly hypocaloric diets: diet V, in which the consumption of vegetables was increased, or diet C, in which the consumption of cereals (especially breakfast cereals) was increased. SUBJECTS: The study subjects were 67 young women with a body mass index of 24-35 kg/m2. INTERVENTIONS: Dietetic, anthropometrics and biochemical data were collected at the start of the study and again at 2 and 6 weeks. RESULTS: The reduction in energy intake was similar in both groups. However, diet C subjects lost significantly more weight. Blood thiamin concentration was higher in group C women than in group V women at 2 and 6 weeks. Compared to initial values, group C subjects showed a higher blood thiamin level at 2 weeks. The highest blood thiamin levels seen in group C women may have been due to their greater thiamin intake, their higher thiamin dietetic density, and a higher thiamin/carbohydrates ratio at both week 2 and 6 of the intervention period. CONCLUSIONS: Increasing the relative consumption of breakfast cereals within the context of a slightly hypocaloric diet can help in weight control and improve thiamine intake and blood levels.

Adult↗

PubMed2006

Changes in folate status in overweight/obese women following two different weight control programmes based on an increased consumption of vegetables or fortified breakfast cereals.

The modification of folate status was analysed in a group of sixty-seven overweight/obese women of childbearing age (20-35 years). Subjects were randomly assigned to one of two slightly hypocaloric diets: diet V (increased consumption of vegetables) or diet C (increased consumption of breakfast cereals). Dietetic, anthropometric and biochemical data were collected at the start of the study and again at 2 and 6 weeks. At 6 weeks a weight loss of 2.0 (sd 1.3) kg was achieved in V subjects and of 2.8 (sd 1.4) kg in C subjects (P < 0.05). At the start of the study, 64.2 % of all subjects had a folate intake of < 67 % of the recommended intake; this fell to just 3 % (7.14 % of V subjects and 0 % of C subjects) by week 6. Significant increases were only seen in C subjects in serum folate concentrations (both at 2 and 6 weeks), accompanied by a significant reduction in serum homocysteine (at week 6). Some 62.1 % of all subjects had serum folate concentrations of > or = 13.6 nmol/l (associated with a very low risk of neural tube defects) at the start of the study, while 87.0 % (85.2 % of V subjects and 88.9 % of C subjects) had concentrations of > or = 13.6 nmol/l at 6 weeks (P < 0.01). Increasing the relative consumption of vegetables/cereals in the context of a slightly hypocaloric diet may therefore be a good way to lose body weight. Breakfast cereals may be of special help with respect to folate status and serum homocysteine levels in overweight/obese young women following energy restriction diets.

Adult↗

PubMed2005

Evaluation of capillary electrophoresis for determining the concentration of dissolved silica in geothermal brines.

The determination of silica concentrations in geothermal brines is widely recognized as a difficult analytical task due to its complex chemical polymerization kinetics that occurs during sample collection and chemical analysis. Capillary electrophoresis (CE) has been evaluated as a new reliable analytical method to measure silica (as silicates) in geothermal brines. Synthetic and geothermal brine samples were used to evaluate CE methodology. A capillary electrophoresis instrument, Quanta 4000 (Waters-Millipore) coupled with a Waters 820 workstation was used to carry out the experimental work. The separation of silicates was completed in approximately 5.5 min using a conventional fused-silica capillary (75 microm i.d. x 375 microm o.d. x 60 cm total length). A hydrostatic injection (10 cm for 20 s at 25 degrees C) was employed for introducing the samples. The carrier electrolyte consisted of 10 mM sodium chromate, 3 mM tetradecyltrimethyl-ammonium hydroxide (TTAOH), 2 mM sodium carbonate, and 1 mM sodium hydroxide, adjusted to a pH 11.0 +/- 0.1. Silicates were determined using an indirect UV detection at a wavelength of 254 nm with a mercury lamp and with a negative power supply (-15 kV). A good reproducibility in the migration times (%R.S.D. approximately 1.6%) based on six non-consecutive injections of synthetic brine solutions was obtained. A linear response between silica concentration and corrected peak area was observed. Ordinary (OLR) and weighted (WLR) linear regression models were used for calculating silica concentrations in all samples using the corresponding fitted calibration curves. The analytical results of CE were finally compared with the most probable values of synthetic reference standards of silica using the Student's t-test. No significant differences were found between them at P = 0.01. Similarly, the atomic absorption spectrometry (AAS) results were also compared with the most probable concentrations of the same reference standards, finding significant differences at P = 0.01.

Calibration↗

PubMed2003

Phase I trial of continuous infusion 5-aza-2'-deoxycytidine.

PURPOSE: To identify a dose of the demethylating agent 5-aza-2'-deoxycytidine (DAC) with acceptable side effects, and to study its effect on the methylation patterns of relevant genes in tumor biopsies before and after treatment with a novel methylation assay using real-time PCR. METHODS: A group of 19 patients with metastatic solid tumors were treated with DAC by continuous intravenous infusion over 72 h, days 1-3 of a 28-day cycle. Tumor biopsies were taken before and 7 days after starting DAC. RESULTS: The dose levels studied were 20, 30 and 40 mg/m(2). Grade 4 neutropenia was found in two of five patients at 40 mg/m(2) and one of six patients at 30 mg/m(2). No objective responses were seen in this study. Steady-state DAC levels of 0.1 to 0.2 microM were achieved in the 30 and 40 mg/m(2) cohorts. Changes in methylation were observed, but no single gene consistently demonstrated evidence of demethylation. CONCLUSIONS: DAC was tolerated at a dose of 30 mg/m(2) per day for a 72-h intravenous infusion. Changes in gene methylation were observed.

Adult↗

PubMed2003

Influence of nutrition on cognitive function in a group of elderly, independently living people.

OBJECTIVE: To study the differences in cognitive status with respect to food habits and energy and nutrient intake in a group of non institutionalised, elderly people. DESIGN: Prospective study. SETTING: The study subjects were independently living, elderly people who spent some of their time at day centres in the Comunidad de Madrid (the Madrid region). The study centres were selected by the Madrid City Hall. SUBJECTS: The study included 168 elderly people aged 65-90 y. All accepted the invitation to participate, met all inclusion criteria, and were free of significant cognitive impairment. INTERVENTIONS: Dietary intake was monitored using a 'food record' for 7 consecutive days including a Sunday. In addition, the 'precise individual weighing' method was used for 5 days in order to monitor the meals taken by the subjects at the centres' canteens. Cognitive capacity was measured using Folstein's mini-mental state examination (MMSE), validated for the Spanish population. RESULTS: Subjects with an adequate cognitive capacity (MMSE>/=28) showed a greater intake of total foods, fish, and alcoholic drinks, but took less foods from the 'various' group (chocolates, cakes, etc). These subjects had a more adequate intake of fatty acids and cholesterol, and a greater intake of vitamins implicated in correct brain function (thiamine, folic acid, vitamin C). CONCLUSIONS: Subjects with satisfactory intellectual function generally had a better diet. This shows the importance of correct nutrition in its maintenance.

Aged↗

PubMed2003

A technique using a membrane flow cell to determine average mass transfer coefficients and tortuosity factors in biofilms.

Average mass transfer coefficients of an inert compound (LiCI) within denitrifying biofilms were monitored during biofilm growth in a membrane flow cell under different flow conditions, until the biofilm reached (pseudo-) steady state. Average effective diffusivities were found to increase with the decrease tortuosity factors of the biofilm matrix. The lowest tortuosity factor corresponded the highest liquid velocity.

Biofilms↗

PubMed2002

Suppressed ion chromatography for monitoring chemical impurities in steam for geothermal power plants.

A suppressed ion chromatography (IC) technique has been evaluated as a chemical monitoring tool for detecting major anions (F-, Cl-, NO3- and SO4(2-)) of condensed steam in geothermal power plants. It is shown that the suppressed IC technique provides a suitable means for preventing possible damage to generating equipment in the geothermal industry. An electrical conductivity detector (0.1 microS sensitivity) with an anion-exchange column (IonPac AS4A-SC), a micro-membrane suppressor (AMMS II), and an isocratic high-pressure pump system were successfully used for detecting low concentrations of inorganic anions. Method detection limits for the anions of interest were <0.184 mg/L. Details of the IC methodology as well as some experimental results obtained during its application for the chemical monitoring of geothermal steam pipes are also described.

Chromatography, Ion Exchange↗

PubMed2002

[Intracranial purulent collections. Review of 34 surgically treated cases in 12 years (1989-2000)].

We made a revision of 34 cases of intracerebral supurations (31 brain abscesses and 3 subdural empyemas) treated at our department of neurosurgery of "Mutua de Terrassa" during the period of 1989-2000. Treatment used was tapping of the abscess and aspiration in 28 cases and craneotomy and resection in only two cases. Three subdural empyemas were treated with burr-holes and aspiration. Results were evaluated using the Glasgow Outcome Scale at 6 months after discharge, resulting in 7 deaths (20.6%), 17 fully recovered patients (50%) and 10 with minor deficits (29.4%). Glasgow Coma Score at admission and the age were the unique variables significantly correlated with the final outcome. After analyzing the cost of treatment in our patients we suggest using antibiotic ambulatory treatment when the disease shows an adequate clinical and radiological response, thus permitting to shorten the usually long period of hospitalization of patients with intracerebral supurative diseases.

Adolescent↗

PubMed2002

The influence of vitamin B2 intake on the activation coefficient of erythrocyte glutation reductase in the elderly.

OBJECTIVE: To evaluate the influence of dietetic vitamin B2 on the activation coefficient of erythrocyte glutation reductase (alpha-EGR) of a group of elderly people. DESIGN: The study subjects were 133, independently-living elderly people, between 65 and 90 years of age. A dietetic study was performed using a 7-day food record. Riboflavin status was measured by determining the alpha-EGR. RESULTS: Some 23.9% of subjects had riboflavin intakes lower than those recommended. At the biochemical level, 9.8% of subjects (7.7% of men and of 10.6% women) showed alpha-EGR>1.2. Those subjects with riboflavin intakes below 90% of those recommended showed significantly higher alpha-EGR levels (1.15+/-0.16), an indication of a poorer riboflavin status at the biochemical level. Those with greater intakes showed lower alpha-EGR values (1.05+/-0.10). Furthermore, the mean consumption of dairy products (an important source of this vitamin) by subjects is insuficiente (341.1+/-159.8 g/day, 2.1+/-1 servings/day). The data show that those with riboflavin intakes below those recommended took 204.7+/-89.4 g/day of milk products (1.3+/-0.5 servings/day) compared to the 384+/-153.1 g/day (2.4+/-1 servings/day) (p<0.001) consumed by those with higher riboflavin intakes. CONCLUSION: Although the mean riboflavin intake is acceptable, there remain some insufficiencies that require attention. It would seem advisable to recommend the elderly increase their intake of milk products. This would be especially important for subjects who take less than two rations per day.

Aged↗

PubMed2001

Capillary electrophoresis for measuring major and trace anions in thermal water and condensed-steam samples from hydrothermal springs and fumaroles.

A new application of capillary electrophoresis for measuring major and trace anions in thermal water and condensed-steam samples is presented. Ten fluid samples were collected from hydrothermal springs and fumaroles located in a volcanic zone of Deception Island, Antarctica. Anion separation was achieved in less than 6 min using indirect UV detection at 254 nm with a negative power supply (-15 kV). The electrolyte consisted of 4.7 mM sodium chromate, 4.0 mM electroosmotic flow modifier (OFM) hydroxide, 10 mM 2-(N-cyclohexylamino)ethanesulfonic acid and 0.1 mM calcium gluconate (pH 9.1). Major anions (Cl-, SO4(2), PO4H2+, and CO3H-) were measured using hydrostatic injection (10 cm for 30 s) at 25 degrees C. Trace amounts of anions (F-, Br-, and NO3-) were better determined by electromigration injection (4 kV, 10 s) at 15 degrees C. Good reproducibility of the migration times (<0.72% RSD), a satisfactory linear response and accuracy as well as acceptable detection limits were successfully obtained.

Anions↗

PubMed2001

Novel immunologic approaches to the management of malignant melanoma.

In the past decade, the discovery of tumor antigens recognized by T cells has revolutionized the tumor vaccine field. The appreciation that peptides are bound to and restricted by major histocompatibility class I and II molecules for immune recognition has encouraged a number of early-phase clinical trials of peptide vaccines. I summarize herein the rationale for and the results of a number of clinical trials of peptide vaccines for melanoma, suggesting that immune and clinical responses can be seen in those with metastatic and resected disease using a variety of surrogate assays. The challenge for the future is to correlate the results of immunologic assays with clinical benefit in patients with advanced cancer.

Adjuvants, Immunologic↗

PubMed2000

Improved capillary electrophoresis method for measuring rare-earth elements in synthetic geochemical standards.

An improved capillary electrophoresis (CE) method for quantifying rare-earth elements (REEs) in synthetic geochemical standards was developed. Synthetic standard solutions were obtained from high purity metal oxides. The separation of REE total group (lanthanum to lutetium) was defined as a primary objective. Special attention was also focused on the optimized separation of europium (Eu) and gadolinium (Gd) because in earlier applications they presented overlapping problems. Their separation and quantitative determinations are essential for geological applications. For the rapid separation of REEs in synthetic geochemical standards, the temperature of the separation device was optimized. An analysis temperature of 15 degrees C enabled both the rapid separation of REEs within 2 min and the overlapping problem of Eu-Gd to be resolved. The detection limits (<0.1 ng) and precision estimates (generally better than 5%) were found to be satisfactory for most geological applications.

Electrophoresis, Capillary↗

PubMed2000

Effect of bilateral ovariectomy and ovarian steroid hormones on the antioxidant systems and plasma malondialdehyde levels in Wistar rats.

We studied in the Wistar rat the effect of bilateral ovariectomy and of the administration of estradiol (E2) alone or together with medroxyprogesterone (MPA) on the lipid peroxidation (MDA) and the enzymatic (SOD and catalase) and non-enzymatic (vitamins A and E) antioxidant systems. At 15 days after castration, we observed no variations in the lipid peroxidation levels (MDA), with there being a slight increase in vitamins A and E (p<0.05), catalase (p<0.01), and SOD (n.s.) activity. The addition of estradiol led to a decline (n.s.) in the MDA values and in the catalase and SOD activity, with no modification of the vit. A and E concentrations. The combined (E2+MPA) therapy did not modify the results obtained with E2 alone, although the catalase decline did now reach significance (p<0.05).

Animals↗

PubMed1998

Pattern recognition analysis of 1H NMR spectra from perchloric acid extracts of human brain tumor biopsies.

Pattern recognition techniques (factor analysis and neural networks) were used to investigate and classify human brain tumors based on the 1H NMR spectra of chemically extracted biopsies (n = 118). After removing information from lactate (because of variable ischemia times), unsupervised learning suggested that the spectra separated naturally into two groups: meningiomas and other tumors. Principal component analysis reduced the dimensionality of the data. A back-propagation neural network using the first 30 principal components gave 85% correct classification of meningiomas and nonmeningiomas. Simplification by vector rotation gave vectors that could be assigned to various metabolites, making it possible to use or to reject their information for neural network classification. Using scores calculated from the four rotated vectors due to creatine and glutamine gave the best classification into meningiomas and nonmeningiomas (89% correct). Classification of gliomas (n = 47) gave 62% correct within one grade. Only inositol showed a significant correlation with glioma grade.

Biomarkers, Tumor↗

PubMed1998

MR imaging of a malignant schwannoma and an osteoblastoma with fluid-fluid levels. Report of two new cases.

One case of malignant schwannoma of the sacrum and another of occipital osteoblastoma were evaluated by MR imaging. Both tumors showed fluid-fluid levels with different signal intensities in the sequences performed. Pathologic examination revealed hemorrhagic fluid in both tumors. Malignant schwannoma and osteoblastoma should be included in the list of bone and soft-tissue with fluid-fluid levels. Our data confirm the non-specificity of this finding, which only suggests the presence of previous intratumoral hemorrhage.

Adult↗

PubMed1998

In vitro cytoreductive effects on multiple myeloma cells induced by bisphosphonates.

In a double blind randomized study, the bisphosphonate drug Pamidronate (Aredia) significantly protected Durie-Salmon stage III multiple myeloma patients from osteolytic bone disease. In the patient sub-group on salvage chemotherapy. Pamidronate treatment was also significantly associated with prolonged survival. To test if this drug could induce direct antitumor effects, we exposed myeloma cells to increasing concentrations of Pamidronate or a more potent bisphosphonate, Zoledronate. A concentration- and time-dependent cytotoxic effect was detected on four of five myeloma cell lines as well as three specimens obtained directly from myeloma patients. Zoledronate-induced cytotoxicity was significantly greater than that of Pamidronate. Cytotoxicity could not be explained by bisphosphonate-induced chelation of extracellular calcium or secondary decrease in production of the myeloma growth factor interleukin-6. Morphological examination, DNA electrophoresis and cell cycle analysis indicated that the bisphosphonate-induced cytotoxic effect consisted of a combination of cytostasis and apoptotic myeloma cell death. Enforced expression of BCL-2 protected against the apoptotic death but not against cytostasis. Most cytotoxic effects were seen between 10 and 100 microM of drug. The results suggest a possible direct anti-tumor effect in myeloma patients treated with bisphosphonates which may participate in their significantly increased survival. This hypothesis should now be further tested in clinical trials.

Antineoplastic Agents↗

PubMed1998

Effects of oral phosphorus supplementation on mineral metabolism of renal transplant recipients.

BACKGROUND: Persistent hyperparathyroidism (HPT) is frequently observed in kidney transplant recipients. Hypophosphataemia is a common biochemical consequence of HPT. Theoretically, oral phosphorus administration may induce negative effects on the control of HPT, though this point has never been demonstrated in kidney-transplant recipients. This study was designed to evaluate the effects of oral phosphorus supplementation on the mineral metabolism of successful kidney transplant recipients. METHODS: Thirty-two kidney transplant recipients with serum creatinine < 2 mg/dl and serum phosphate levels <3.5 mg/dl were included in the study. After a washout period in which oral phosphorus supplementation was discontinued, the following parameters were determined (F0 period): serum calcium, phosphate, alkaline phosphatase, uric acid, bicarbonate, PTH, 1,25-dihydroxyvitamin D3 (1,25 (OH)(2)D) and 25-hydroxyvitamin D3 (25OHD). Creatinine clearance, calcium, and phosphate excretion were determined from a 24-h urine sample. The same determinations were repeated (F1 period) after all patients received 1.5 g of oral phosphorus for 15 days. For data analysis, patients were divided into two subgroups (optimal and suboptimal) according to allograft function (Ccr>or < 70 ml/min/1.73 m2). RESULTS: In the F0 period, only nine of 32 patients had PTH levels within the normal range (<65 pg/ml). The mean concentrations of PTH, 1,25(OH)(2)D and 25OHD were 132+/-97pg/ml, 40.5+16pg/ml and 12.5+/-8.2 ng/ml respectively. Phosphorus supplementation led to significant reductions in serum calcium and 1,25(OH)(2)D concentrations, as well as in urinary calcium excretion in the whole group. On the contrary, serum phosphate, PTH, and urinary phosphate excretion increased significantly. The percentage increase in PTH concentrations after phosphorus supplementation were similar in patients with optimal and suboptimal allograft function (33 vs 36%). The reduction of 1,25 (OH)(2)D concentrations after phosphorus supplementation was observed mainly in the subgroup with optimal allograft function (21% reduction with respect to baseline values), while the mean 1,25(OH)(2)D concentrations in patients with suboptimal allograft function scarcely changed (1.4% increase). Changes in 1,25(OH)(2)D concentrations after phosphorus supplementation, expressed as a percentage of the initial concentrations, correlated positively with the percentage changes in PTH concentrations for the whole group, as well as for each subgroup. The best determinants for the percentage and the absolute increase in PTH concentration after phosphorus supplementation was the final serum phosphate concentration (F=4.84, r=0.37, P=0.035) and the increase in serum phosphate (F=7.69, r=0.45, P= 0.009) respectively. CONCLUSIONS: Oral phosphorus supplementation led to a significant increase in the PTH concentration of kidney transplant recipients. The mean 1,25(OH)(2)D concentration decreased mainly in recipients with optimal allograft function. The counterbalance effect of PTH on 1,25(OH)(2)D production may account for the relative preservation of 1,25(OH)2D levels in recipients with suboptimal allograft function.

Administration, Oral↗

PubMed1998

Are plasma 1,25-dihydroxyvitamin D3 concentrations appropriate after successful kidney transplantation?

We studied 28 patients with parathyroid hormone (PTH) concentrations >65 pg/ml immediately prior to kidney transplant and who had stable allograft function with serum creatinine <2 mg/dl. After 12-18 months of transplantation, biochemical parameters (including 25-hydroxy- and 1,25-dihydroxy-vitamin D3) were studied. Patients were divided into three groups according to their PTH concentrations. Patients with renal transplant were compared with 50 healthy subjects and 20 patients with primary hyperparathyroidism. The mean 1,25-dihydroxy-vitamin D3 concentration of the transplant patients did not differ from the controls, but was lower than in patients with primary hyperparathyroidism. Using univariate linear regression analysis, 1,25-dihydroxy vitamin D3 correlated positively with PTH (P=0.008) and serum calcium (P=0.0015), and inversely with creatinine clearance (P=0.01). However, it did not correlate significantly with serum phosphorus. Our data suggest that renal transplant recipients may have an inappropriate production of 1,25-dihydroxy vitamin D3; suboptimal allograft function may be a major limiting factor.

Adult↗