Biomedical subjects

V González

Publications and source records attributed to V González.

At least 19 recordsLinked to original sources

PubMed2006

Reactions, characterization and uptake of ammoxidized kraft lignin labeled with 15N.

Ammoxidation of kraft lignin was carried out in a Parr reactor using (15)NH(3) as the main nitrogen source. Reaction parameters were set up until a total nitrogen content of approximately 13 wt.% in lignin was achieved, in accordance with conditions of previous studies. Analytical tools such as FTIR, Py-GC/MS, and solid state NMR were used in this research. The nature of nitrogen bondings is discussed. The incorporation of the (15)N from ammoxidized lignin was followed in pumpkins (Zucchini cucurbita pepo L.) by means of (15)N emission spectroscopy.

Ammonia↗

PubMed2005

Clinical usefulness of total hepatitis C virus core antigen quantification to monitor the response to treatment with peginterferon alpha-2a plus ribavirin*.

SUMMARY: Early virological response may predict outcome following treatment with peginterferon alpha-2a and ribavirin in patients chronically infected with hepatitis C virus (HCV). As total HCV core antigen may constitute an alternative direct marker to HCV RNA for assessing the levels of viraemia in such patients, we evaluated the correlation between HCV core antigen and HCV RNA, and whether HCV core antigen at baseline, 4 and 12 weeks after treatment could predict sustained virological response (SVR) to combined therapy, in comparison with HCV RNA. A total of 290 serum samples from 58 previously treatment naïve chronic HCV patients were examined for HCV core antigen and HCV-RNA by means of quantitative HCV RNA when receiving combination therapy for the first time. SVR was significantly associated with basal HCV core antigen but not with HCV RNA. There was a good correlation between HCV core antigen and HCV RNA (r(2) = 0.781). The negative predictive value of HCV core antigen testing in predicting nonresponse at weeks 4 and 12 were 75 and 100%, and for undetectable or a 2-log drop in HCV RNA were 69.6 and 75% respectively. HCV core antigen detection is quick, and easy to perform alternative to HCV RNA, and could be used as a marker of HCV viraemia for monitoring the progress of therapy.

Antiviral Agents↗

PubMed2005

[Prevalence of chronic kidney disease in community-dwelling elderly and associated cardiovascular risk factors].

BACKGROUND: Chronic kidney disease is a major public health problem in developed countries. The incidence of patients on dialysis is increasing progressively in the last years. The ageing population and increasing incidence of diabetes and hypertension are the main causes. Moreover, the level of kidney function is now recognised as a major risk factor for cardiovascular disease, even in mild cases. There is a great unaware about the prevalence of mild to moderate chronic kidney disease in the general population. The aim of the present study was to know the kidney function level in our general population over 64 years old, and the associated cardiovascular risk. METHODS: This is an epidemiological descriptive cross-sectional study, obtained by a representative random sampling of the population over 64 years living in the reference area of our Hospital. The glomerular filtration rate was estimated by the Cockroft-Gault formula and the MDRD equations. Kidney function has been classified by the K/DOQI stages. We examined the univariate and multivariate association between the estimated glomerular filtration rate and the presence of cardiovascular events. RESULTS: We analysed 253 subjects aged 65 to 93 years (mean 72 +/- 5.4). Present comorbidities were: HTA 64%, dislipemia 29%, diabetes 14%, active smokers: 10% of men, 1,5% of women. A previous cardiovascular event was present in 11% of patients (15% of men; 6,8% of women). A serum creatinin level over 1,3 and 1,5 mg/dl was present in 3,8% of women and 8% of men respectively. Nevertheless, chronic kidney insufficiency (estimated clreatinie clearance less than 60 mix') was present in 31-49% relying on the utilised formula. In addition to age, sex, and diabetes, an independent graded association was observed between reduced glomerular filtration rate and the existence of cardiovascular events. CONCLUSIONS: We have confirmed a high prevalence of renal insufficiency among elderly people, usually not detected by the isolated plasma creatinin concentration This aspect is important for cardiovascular stratification risk and medical decisions (diagnostic and/or therapeutic). The level of glomerular filtration rate is independently associated with cardiovascular events.

Aged↗

PubMed2004

Evaluation of a commercial enzyme immunoassay for HIV screening in urine.

A cross-sectional study was conducted to evaluate the utility of a commercial enzyme immunoassay (EIA) as a screening test for detecting HIV-1 antibody in urine in a population at risk for HIV infection in Catalonia, Spain. Paired urine and serum samples were collected consecutively from 99 patients who attended two drug-dependency treatment centres and 151 patients who attended a sexually transmitted diseases (STD) clinic in Barcelona. Antibodies against HIV in urine samples were detected using the Calypte HIV-1 Urine EIA (Calypte Biomedical Corporation, Berkeley, CA, USA) and confirmed by urine-based Western blot (WB) analysis. Sera were analysed using Bioelisa HIV-1+2 EIA (Biokit Laboratories, Barcelona, Spain), and the results were verified using serum-based WB analysis. Results of both urine and serum testing were available for 246 of 250 participants. For 52 individuals the results of both urine and serum testing were positive and for five the results were discordant (2 with urine-negative/serum-positive results and 3 with urine-positive/serum-negative results). The respective sensitivity and specificity values obtained for the urine EIA were 100% and 96.2% for intravenous drug users (IDUs) and 80% and 99.3% for persons attending the STD clinic. According to the 1997 UNAIDS/WHO strategy I recommendations, these values are acceptable for surveillance purposes, particularly in populations with a high prevalence of HIV infection.

Cross-Sectional Studies↗

PubMed2004

Rapid diagnosis of Staphylococcus aureus bacteremia using S. aureus PNA FISH.

In the study presented here, the performance of the S. aureus PNA FISH assay was evaluated using 285 blood cultures (from 104 patients) that had gram-positive cocci resembling staphylococci on Gram stain. The new molecular test is based on a fluorescence in situ hybridization assay using peptide nucleic acid probes targeting Staphylococcus aureus 16S rRNA and is designed for the rapid identification of Staphylococcus aureus directly from positive blood cultures. The sensitivity, specificity, and positive and negative predictive values of the S. aureus PNA FISH for the rapid identification of Staphylococcus aureus directly from positive blood culture bottles were 100, 99.4, 99.2 and 100%, respectively.

Bacteremia↗

PubMed2004

Large quantum nonlinear dynamic susceptibility of single-molecule magnets.

The nonlinear dynamical response of Mn12 single-molecule magnets is experimentally found to be very large, quite insensitive to the spin-lattice coupling constant, and displaying peaks reversed with respect to classical superparamagnets. It is shown that these features are caused by the strong field dependence of the relaxation rate due to the detuning of energy levels between which tunneling takes place. The nonlinear susceptibility technique, previously overlooked, is thus proposed as a privileged probe to ascertain the occurrence of quantum effects in mesoscopic magnetic systems.

Journal Article↗

PubMed2004

Preventive effects of D-004, a lipid extract from Cuban royal palm (Roystonea regia) fruits, on testosterone-induced prostate hyperplasia in intact and castrated rodents.

Benign prostatic hyperplasia (BPH) is the noncancerous, uncontrolled growth of prostate gland cells and stroma that can cause difficulty urinating. Fruit lipid extracts from saw palmetto, a palm from the Arecaceae family, are used for BPH management. The Cuban royal palm, Roystonea regia, is also a member of the Arecaceae family and therefore it was appropriate to investigate the protective effects of Roystonea regia fruit lipid extracts on prostatic hyperplasia. The aim of this study was to investigate whether D-004, a lipid extract from Roystonea regia fruits, prevented testosterone-induced PH in castrated and intact rodents. Two series of experiments were performed. The first one was conducted in castrated and intact rats, distributed into five groups of 10 rats per group. The negative control group was injected with soy oil and treated orally with vehicle, while the four testosterone-injected groups were treated with vehicle (positive control), D-004 100, 200 and 400 mg/kg, respectively. The other experiment was conducted in castrated and intact mice. These were distributed into four groups of 10 mice per group: a negative control group and three testosterone-injected groups, of which one was a positive control, while two received D-004 200 and 400 mg/kg, respectively. At study completion, the rodents were sacrificed and prostates removed and weighed. D-004 at doses of 100, 200 and 400 mg/kg significantly and dose-dependently prevented prostate enlargement in intact and castrated rats and mice. The percentage inhibitions obtained in mice were greater: 77% and 84% for intact and castrated mice, respectively. D-004 therapy did not affect body weight. It is concluded that D-004 administered orally significantly prevented testosterone-induced prostate enlargement in both intact and castrated rodents, indicating that an endogenous supply of testosterone is not necessary to observe such an effect The results of the present investigation support further studies of D-004 on experimental models of prostatic hyperplasia.

Animals↗

PubMed2003

Evaluation of two different cell lysis methods for releasing mycobacterial nucleic acids in the INNO-LiPA mycobacteria test.

The INNO-LiPA Mycobacteria Test (Innogenetics, N.V., Belgium) is a PCR-based reverse hybridization assay for the simultaneous identification of several mycobacterial species. We evaluated two simplified lysis methods for mycobacterial DNA release for application in the INNO-LiPA Mycobacteria Test. The two methods were based on either (i) heat treatment or (ii) sonication. Both methods were performed directly on 45 positive liquid cultures (MB-BacT, BioMérieux, Marcy l'Etoile, France) containing 17 different mycobacterial species. These two simple lysis procedures demonstrated similar effectiveness (100%) to that recommended by the manufacturer. They also significantly shortened the time required for mycobacterial DNA release.

Bacterial Typing Techniques↗

PubMed2003

[Neurological emergencies in a university hospital].

INTRODUCTION: We analyze the demand and to describe the neurological assistance in a university hospital. MATERIAL AND METHODS: We have performed a retrospective and descriptive study of patients attended in the emergency services by neurologists from June 2000 to May 2001. The inventory and analysis has been carried out across a database in which we codify the reports of the patients diagnosed by means of CIE-9. We have been selected one month where we have collected all calls that neurologist have received, not only those of which reports was realized and codified. RESULT: The total number of neurological patients attended in a year was 1,864 representing 2.85% of all emergencies. The most frequent diagnostic were: cerebrovascular stroke (24.57%), epilepsy (13.06%) and headache (6.07%). Few seasonal variation was noted. There was no difference for sex. In the month's study there were 426 patients, which represented 7.78% of all medical urgencies. The most frequent calls came from internal medicine (65.02%). CONCLUSION: Neurological emergencies constitute a large percentage of third level hospital's emergencies which justify a neurologist in the medical emergencies team.

Emergency Service, Hospital↗

PubMed2003

Stability studies of tablets containing 5 mg of policosanol.

The stability studies of tablets containing 5 mg of policosanol, a new cholesterol lowering drug, were conducted to predict an expiration date and to search the appearance of putative degradation products. All quality parameters such as colour, moisture content, hardness, disintegration, policosanol content and microbiological limits of the tablets were assessed. The effect of extreme treatments such as acid and basic hydrolysis, oxidative and photolytic degradation as well as thermal degradation, on the policosanol content was studied. In addition, studies under extreme conditions of storage [(40 +/- 2) degree C and (75 +/- 5)% R.H.] as well as 37, 45, 55 and 60 degrees C combined with 50, 75 and 92% R.H.) and under ambient conditions of storage for climatic zones II and IV were performed. These studies demonstrate that these tablets are a stable pharmaceutical formulation, without significant changes in their quality criteria at the stressed conditions used, so that policosanol content remains unchanged during the entire studies. The chromatographic profile of the samples after 9 months of thermal degradation shows chromatographic peaks that corresponds to the palmitate and stearate esters of octacosanoyl, triacontanoyl and hexacosanoyl, being the only degradation products observed on these studies.

Anticholesteremic Agents↗

PubMed2002

Determination of polycyclic aromatic hydrocarbons in seawater by high-performance liquid chromatography with fluorescence detection following micelle-mediated preconcentration.

In this work, the nonionic surfactant polyoxyethylene-10-lauryl ether has been used for the extraction and preconcentration of 14 polycyclic aromatic hydrocarbons, classified as priority pollutants by the US Environmental Protection Agency, from seawater samples. The cloud-point preconcentration previous separation by HPLC and quantification using fluorimetric detection and wavelength programming allow to determine these pollutants with detection limits ranging from 1.0 to 1.5 x 10(2) ng/l with RSDs better than 10.4%. The methodology is evaluated using well-established extraction and preconcentration methods and GC-MS.

Chromatography, High Pressure Liquid↗

PubMed2001

Cloud-point preconcentration and HPLC determination of polycyclic aromatic hydrocarbons in marine sediments.

Cloud-point methodology has been used to develop a new procedure for preconcentration of polycyclic aromatic hydrocarbons previously extracted from marine sediment with a micellar polyoxyethylene-10-lauryl ether medium by microwave- or ultrasound-assisted extraction. The optimum conditions for preconcentration and determination of PAH by HPLC with UV detection were established. The optimized procedure was applied to determination of these analytes in fortified marine sediment. The mean recoveries obtained after extraction and preconcentration by use of microwave- or ultrasound-assisted extraction were 105.8 and 99.5%, respectively. Precision, however, is considerably higher when extraction is performed ultrasonically.

Chromatography, High Pressure Liquid↗

PubMed2001

Presence of a simple tandem repeat in the ITS1 region of the Xylariales.

A Simple Tandem Repeat sequence of 11 nucleotides has been found in the ITS1 region of the rDNA of members of Order Xylariales. The number of repetitions detected ranged from one to six, and they could be found in pure tandem or interspersed. The same core sequences have also been found in DNA from other organisms, although usually not repeated in tandem. These repetitions could have been generated by slipped strand mispairing. The presence of this sequence increases the normal rate of divergence in the ITS1 of the Xylariales. The phylogenetic implications of the presence of this sequence in the molecular taxonomy of Xylariales are also discussed.

Ascomycota↗

PubMed2001

Rapid detection of several mycobacterial species using a polymerase chain reaction reverse hybridisation assay.

The ability of a polymerase-chain-reaction-based technique combined with a reverse hybridisation line-probe assay to detect and identify eight of the most clinically significant mycobacterial species directly from cultures in liquid medium was evaluated. The line-probe assay allows simultaneous identification of eight different mycobacterial species. Ninety-seven mycobacterial strains belonging to 22 different species were evaluated. All strains were previously inoculated into MB/BacT bottles (Organon Teknika, USA). The sensitivity and specificity of the test when applied on positive MB/BacT liquid cultures containing isolates from mycobacterial species included as specific probes on the line-probe assay strip was 100% and 100%, respectively. These results further support the potential clinical usefulness of this technique in the diagnosis of mycobacterial infections.

Bacterial Typing Techniques↗

PubMed2001

Optimization of 4A zeolite synthesis as recovery of wastes from aluminum finishing.

A model representing the synthesis process of 4A zeolite from wastes of aluminum finishing plants was obtained and validated through statistical tests. From this model, the optimum values for the molar ratios SiO2/ Al2O3, Na2O/SiO2 and H2O/Na2O, which define the type and quality of the synthesized zeolite, were estimated for the use of these wastes as raw material. The obtained zeolites could be used as water softeners in the formulation of detergents. The resulting liquors could be reused in the cleaning of the extrusion matrices used for aluminum profiles or recycled for new zeolites synthesis.

Aluminum↗

PubMed2001

Fish oil (n-3) polyunsaturated fatty acids beneficially affect biliary cholesterol nucleation time in obese women losing weight.

It has been reported that intake of (n-3) polyunsaturated fatty acids (PUFA) reduces the risk of coronary heart disease and decreases biliary cholesterol saturation in the bile of gallstone patients. We investigated the effect of n-3 PUFA on cholesterol saturation index (CSI) and nucleation time (NT) in obese subjects who were losing weight. This was a double-blind, placebo-controlled clinical trial. Obese women (n = 35) with a body mass index (BMI) > or = 30 kg/m(2), with no prior history of gallstones or cholecystectomy by ultrasound were first studied to ensure absence of stones or biliary sludge. The women were then assigned to a hypocaloric regimen [5.02 MJ (1200 kcal)/d] and to receive 1200 mg/d of ursodeoxycholic acid (UDCA), 11.3 g/d of (n-3) PUFA or a placebo for 6 wk. BMI, CSI and NT were recorded at baseline and at the end of the experimental period. BMI decreased 5.75 +/- 2.7%/mo (range, 1.5-12.42%/mo) during the experiment. The CSI did not change in any of the groups. Cholesterol NT decreased significantly in the UDCA and placebo groups, but not in the (n-3) PUFA group. None of the women had developed gallstones at 6 wk. These results suggest that (n-3) PUFA maintain the CSI and NT in obese women during rapid weight loss, which probably results in the prevention of cholesterol gallstone formation.

Adult↗

PubMed2000

Left ventricular mass index and sports: the influence of different sports activities and arterial blood pressure.

BACKGROUND: The mechanisms by which endurance training produces physiological hypertrophy have been thoroughly investigated but not with young athletes. The aim of our study was to investigate arterial blood pressure exercise responses in young athletes who started heavy training by the age of 11, participating in metabolically different sports (cycling, kayaking, and soccer) and to analyse the influence that arterial blood pressure at maximum exercise and VO(2) max could have on the development of cardiac mass in these subjects. SUBJECTS AND METHODS: We studied a group of well trained normotensive male subjects, comprising 37 cyclists, 15 soccer players and 12 canoeists (mean age, 16+/-1 years). Evaluation included a clinical history and physical examination, M-mode and two-dimensional echocardiography, 12-lead resting electrocardiogram and a graded exercise test with direct determination of VO(2) max. Systolic and diastolic blood pressure were measured at rest and maximum exercise. Determination of the left ventricular mass index (LVMI) was performed using Devereux's formula with correction for the body surface area. RESULTS: Cyclists showed values of LVMI in g m(-2) significantly higher than those of other subjects (123 vs. 92 and 113). Canoeists showed the maximal arterial blood pressure at maximum exercise in mmHg (190 vs. 172 and 170) and cyclists showed the maximal VO(2) ml kg(-1) min(-1) uptake (57.6 vs. 48.5 and 53.3). A linear correlation was found between LVMI and VO(2) max (r=0.4727, P<0.001) and this correlation was also significant with systolic blood pressure at maximum exercise (r=0.2909, P<0.01). No differences in LVMI were found when comparing those subjects who presented systolic blood pressure at maximum exercise equal or greater than 195 mmHg with those who presented less than this value. CONCLUSIONS: It can be concluded that VO(2) max is the variable that better correlates with the LVMI. Athletes who reach greater systolic blood pressures at peak exercise have a tendency to develop greater LVMI. In comparison with soccer players and canoeists, cyclists are the sportsmen who develop a greater LVMI and VO(2) max.

Adolescent↗

PubMed2000

Reciprocal domain evolution within a transactivator in a restricted sequence space.

offhough the concept of domain merging and shuffling as a major force in protein evolution is well established, it has been difficult to demonstrate how domains coadapt. Here we show evidence of coevolution of the Sinorhizobium meliloti NifA (SmNifA) domains. We found that, because of the lack of a conserved glycine in its DNA-binding domain, this transactivator protein interacts weakly with the enhancers. This defect, however, was compensated by evolving a highly efficient activation domain that, contrasting to Bradyrhizobium japonicum NifA (BjNifA), can activate in trans. To explore paths that lead to this enhanced activity, we mutagenized BjNifA. After three cycles of mutagenesis and selection, a highly active derivative was obtained. Strikingly, all mutations changed to amino acids already present in SmNifA. Our artificial process thus recreated the natural evolution followed by this protein and suggests that NifA is trapped in a restricted sequence space with very limited solutions for higher activity by point mutation.

Amino Acid Sequence↗