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Biomedical subjects

B Hernández

Publications and source records attributed to B Hernández.

At least 19 recordsLinked to original sources
PubMed2006

Intrahepatic DNA vaccination: unexpected increased resistance against murine cysticercosis induced by non-specific enhanced immunity.

Experimental murine cysticercosis caused by Taenia crassiceps has proved to be a useful model with which to test the efficacy of new vaccine candidates and delivery systems against pig cysticercosis. A high level of protection against murine cysticercosis was previously observed by intramuscular or intradermal DNA immunization with the use of the sequence of the recombinant KETc7 antigen cloned in pcDNA3 (pTc-sp7). To determine the effect of KETc7 differential expression in DNA vaccination, KETc7 was cloned in pGEM 11Zf(+) under the control of the tissue-specific regulatory promoter phosphoenolpyruvate carboxykinase (pPc-sp7). A high level of protection was induced by intrahepatic immunization with pPc-sp7, pTc-sp7 and the empty vector in the absence of any specific immunity. The empty vector pGEM 11Zf(+), the plasmid with the highest content of CpG sequences, provided to the most efficient protection. This protection was related to an increased number of splenocytes, enhanced nonspecific splenocyte proliferation, and intensified intrahepatic INF-gamma production. Overall, intrahepatic plasmid CpG-DNA immunization provokes an exacerbated nonspecific immune response that can effectively control Taenia crassiceps cysticercosis.

Animals↗
PubMed2005

The effect of soybean soapstock on the quality parameters and fatty acid composition of the hen egg yolk.

The effects of increasing proportions of soybean soapstock (SSS) in laying hen diets on egg quality parameters and on the fatty acid (FA) composition of the yolk were studied. One hundred sixty Babcock B-300 x laying hens, 20 wk of age, were allotted to 5 dietary treatments comprising a control diet (D5) with soybean oil at 100% or SSS in proportions of 25% (D1), 50% (D2), 75% (D3), and 100% (D4) replacing the oil source in commercial-type diets throughout the 15-wk laying period. Egg quality parameters were recorded weekly. Four pooled yolks for each treatment were collected at 0, 9, and 15 wk, and their FA profiles were determined. Egg weight, shell thickness, shape index, and Haugh unit were not influenced by dietary treatment. The concentrations of saturated FA (SFA) in yolks were generally kept at a constant level, regardless of the percentage of SSS in the hen diets. Total monounsaturated FA (MUFA) content did not vary over the course of the experiment, except for C14:1. After 15 wk of feeding, the total polyunsaturated FA (PUFA) n-3 increased in yolks of all diets. Among the long-chain PUFA, the percentage of C20:4 (arachidonic acid) was less affected. Inclusion of 100% SSS allowed production of eggs with similar PUFA/SFA and n-6/n-3 ratios when compared with eggs from hens fed D5. As SSS represents one-third of the oil cost, its inclusion in layer diets could represent an important economic benefit.

Animals↗
PubMed2004

Complex unitary vectors for the direction of propagation and for the polarization of electromagnetic waves in absorbing isotropic media.

We introduce a formalism based on complex unitary vectors for the direction of propagation and for the polarization in order to describe in detail the propagation of inhomogeneous plane waves in absorbing isotropic media. We obtain analytic expressions for the displacement vector, the electric field, the magnetic field, and the Poynting vector, and we study their geometry in terms of the geometrical interpretation of the complex directions of propagation inside the material. We introduce a complex coordinate system based on complex unitary vectors, where the description of the polarization states of the field vectors and the Poynting vector becomes simpler. The physical meaning and the interpretation of the mathematical operations involving these complex unitary vectors is provided.

Journal Article↗
PubMed2004

Prevalence of genotypic resistance in untreated HIV-infected patients.

The aims of this retrospective study are to assess the prevalence of primary resistances to antiretroviral drugs, both reverse transcriptase and protease inhibitors in untreated patients from Spain, and to determine their possible association with several epidemiological variables. A total of 148 samples belonging to 145 patients were processed using the genotypic technique VERSANT HIV 1 (LiPA) in order to study the presence of mutations at codons 41, 69, 70, 74, 75, 103, 106, 151, 181, 184 and 215 of the reverse transcriptase gene (VERSANT HIV 1 RT) and at codons 30, 46, 48, 50, 54, 82, 84 and 90 of the protease gene (VERSANT HIV 1 Protease). The patients' epidemiological variables which could be relevant to HIV infection were also analyzed. The successful amplification rate was 77.70% for LiPA RT and 91.21% for LiPA P. In the case of LiPA RT, statistical significance (p < 0.05) was observed when successful amplification was related to viral load level (p < 0.001). Global prevalence of resistance was 20.27%. Mutations in the reverse transcriptase gene were found in eight samples (5.40%). Using LiPA P, mutations were detected in 16.21% of cases, with V82A being the most frequently detected mutation (15/24, 62.50%) in nine samples. The V82A mutation was found alone (66.6%) and it was found together with the I84V mutation in five samples (20.83%). I84V was the second most frequently detected mutation (13/24, 54.16%). No statistical significance was found for any of the epidemiological variables. Due to the problems encountered in a high percentage of samples, the authors concluded that the amplification technique should be improved. The prevalence of resistance detected was around the mean of that found by other authors.

Drug Resistance, Viral↗
PubMed2003

The effects of superior ovarian nerve sectioning on ovulation in the guinea pig.

The effects on spontaneous ovulation associated with the unilateral or bilateral sectioning of the superior ovarian nerves (SON) were analyzed in guinea pigs at different time intervals of the estrous cycle. Day 1 of the estrous cycle was defined as the day when the animal presents complete loss of the vaginal membrane (open vagina). Subsequent phases of the cycle were determined by counting the days after Day 1. All animals were autopsied on the fifth day of the estrous cycle after surgery. Sectioning the right, left, or both SONs on day 5 (early luteal phase) resulted in a significant increase in the number of fresh corpora lutea. Ovulation increased significantly when the left SON (L-SON) was sectioned during late follicular phase (day 1) and medium luteal phase (day 8). When surgery was performed on days 1 or 8, neither sectioning the right SON (R-SON) nor sectioning the SON bilaterally had an apparent effect on ovulation rates. Similarly, ovulation rates were not affected when unilateral (right or left) or bilateral sectioning of the SON was performed during late luteal phase two (day 12). Unilateral or bilateral sectioning of the SON performed during the early luteal phase (day 5) was associated with a significant decrease in uterine weight. A comparable effect was observed when the L-SON was sectioned during late follicular phase (day 1), or medium luteal phase (day 8). No effects on uterine weight were observed when unilateral or bilateral sectioning of the SON was performed during late luteal phase. Our results suggest that in the guinea pig the SON modulates ovulation, and that the degree of modulation varies along the estrous cycle. The strongest influence of the SONs on ovulation occurs during early luteal phase, and decrease thereafter, being absent by late luteal phase. In addition, sectioning the left or the right SON caused different responses by the ovaries of adult guinea pigs. This paper discusses the mechanisms by which ovulation increased when the SON was surgically cut.

Animals↗
PubMed2003

Factors associated with the evolution of the viral load in individuals with HIV infection.

The temporal evolution of the viral load (VL) in a group of patients under clinical care and the identification of individual variables that determined this evolution was studied using a retrospective descriptive study of the VL determinations on 1336 patients between September 1996 and June 2000. During follow-up, patients' VLs increasingly fell below the detection threshold. Those patients who had received antiretroviral treatment prior to the monitoring of the viraemia presented lower VLs at the start of their follow-up. Those patients who had been cared for on the same unit throughout their follow-up maintained lower VLs. Female patients uniformly presented lower VL results than the males. The immunological status at the beginning of follow-up and the basal VL determined the initial evolution of the patients' VL, although it did not do so in the final stages of follow-up. The immunological and virological state at the onset of the follow-up determines the evolution of the patients' VL.

Adolescent↗
PubMed2002

Prevalence of genotypic resistance in untreated HIV patients in Spain.

The aims of this retrospective study were to assess the prevalence of primary genotypic resistance to antiretroviral drugs in untreated HIV patients in Spain using the line probe assay and to determine its possible relationship to several epidemiological variables. The global prevalence of primary resistance was 12.5%. Primary mutations in the reverse transcriptase gene were found in two (2.2%) samples: M41L, K70R and M184 V were found in one sample and K70R in another. Primary mutations in the protease gene were detected in 12% of cases; V82A was the mutation most frequently detected (11/12, 91.6%). No statistical significance was found for any of the epidemiological variables studied. In conclusion, the prevalence of primary resistance detected is similar to that found by other authors.

Adolescent↗
PubMed2002

Hydrophobic similarity between molecules: a MST-based hydrophobic similarity index.

A similarity index based on the hydrophilic/hydrophobic properties of molecules is presented. Such an index is defined based on the fractional partition of the free energy of solvation developed within the framework of the self-consistent reaction field MST model, which divides the free energy of solvation or the free energy of transfer into contributions assigned to the surface elements defining the solute/solvent interface. These surface contributions can be integrated to derive atomic or group contributions. The suitability of the index to compute the molecular similarity based on hydrophobic/hydrophilic properties is examined by considering their application in a variety of test systems, including structure-activity relationships, absorption properties, and molecular recognition. The similarity index is expected to be a very powerful tool in molecular similarity studies for compounds of chemical, biochemical, and pharmaceutical interest.

Algorithms↗
PubMed2001

Ab initio vibrational calculations on ara-T molecule: application to analysis of IR and Raman spectra.

The FTIR and FT-Raman spectra are reported for the arabinonucleoside ara-T (1-beta-D-arabinofuranosylthymine), which shows antiviral activity. The accurate knowledge of the vibrational modes is a prerequisite for the elucidation of drug-nucleotide and drug-enzyme interactions. The FTIR and FT-Raman spectra of ara-T were recorded from 4000 to 30 cm(-1). A tetradeuterated derivative (deuteration at N3, and hydroxyl groups O'2, O'3, and O'5) was synthesized and the observed isotopic shifts in its spectra were used for the vibrational analysis of ara-T. The theoretical frequencies and the potential energy distribution (PED) of the vibrational modes of ara-T were calculated using the ab initio Hartree-Fock/3-21G method. An assignment of the vibrational spectra of ara-T is proposed considering the scaled PED and the observed band shifts under deuteration. The scaled ab initio frequencies were in reasonable agreement with the experimental data.

Antiviral Agents↗
PubMed2001

Two epitopes shared by Taenia crassiceps and Taenia solium confer protection against murine T. crassiceps cysticercosis along with a prominent T1 response.

Taenia crassiceps recombinant antigens KETc1 and KETc12 have been shown to induce high level of protection against experimental murine T. crassiceps cysticercosis, an experimental model successfully used to test candidate antigens for use in vaccination against porcine Taenia solium cysticercosis. Based on the deduced amino acid sequence, KETc1 and KETc12 were chemically synthesized in linear form. Immunization with KETc1 induced 66.7 to 100% protection against murine cysticercosis, and immunization with KETc12 induced 52.7 to 88.1% protection. The elicited immune response indicated that both peptides contain at least one B-cell epitope (as demonstrated by their ability to induce specific antibodies) and one T-cell epitope that strongly stimulated the proliferation of T cells primed with either the free peptide or total cysticercal T. crassiceps antigens. The high percentage of spleen cells expressing inflammatory cytokines points to the likelihood of a T1 response being involved in protection. The protective capacity of the peptides and their presence in all developmental stages of T. solium point to these two epitopes as strong candidates for inclusion in a polyepitopic synthetic vaccine against T. solium pig cysticercosis.

Animals↗
PubMed2000

Misincorporation of 2'-deoxyoxanosine into DNA: a molecular basis for NO-induced mutagenesis derived from theoretical calculations.

A wide range of theoretical methods, including high level ab initio, density functional, self-consistent reaction field, molecular dynamics and thermodynamic integration calculations, have been used to analyze the mutagenic properties of oxanosine. The major tautomeric forms in the gas phase and aqueous solution have been determined. The ability of oxanosine to recognize thymine and cytosine in the gas phase and in the DNA environment has been compared with that of guanine. A physicochemical explanation for the mutagenic properties of oxanosine is suggested.

Base Pairing↗
PubMed2000

Mixed QM/MM molecular electrostatic potentials.

A new method is presented for the calculation of the Molecular Electrostatic Potential (MEP) in large systems. Based on the mixed Quantum Mechanics/Molecular Mechanics (QM/MM) approach, the method assumes both a quantum and classical description for the molecule, and the calculation of the MEP in the space surrounding the molecule is made using this dual treatment. The MEP at points close to the molecule is computed using a full QM formalism, while a pure classical evaluation of the MEP is used for points located at large distances from the molecule. The algorithm allows the user to select the desired level of accuracy in the MEP, so that the definition of the regions where the MEP is computed at the classical or QM levels is adjusted automatically. The potential use of this QM/MM MEP in molecular modeling studies is discussed.

Algorithms↗
PubMed2000

Evaluation of an immunocapture-agglutination test (Brucellacapt) for serodiagnosis of human brucellosis.

We evaluated the validity and the usefulness of a new test for the diagnosis of human brucellosis based on an immunocapture-agglutination technique. A total of 315 sera from 82 patients with a diagnosis of brucellosis, 157 sera from patients in whom brucellosis was suspected but not confirmed, and 412 sera from people living in rural areas with endemic brucellosis were studied. The seroagglutination test (SAT), Coombs anti-Brucella test, and Brucellacapt test were evaluated. All the initial sera from the 82 patients proved to be positive in Brucellacapt and Coombs tests, while only 75 (91.4%) were positive in the SAT. If a >/=1/160 diagnostic threshold titer was defined for the Brucellacapt test, Coombs test, and SAT, the sensitivities were 95.1, 91.5, and 65.8%, respectively. Taking the same diagnostic threshold titer for the 157 sera from the unconfirmed but suspected patients, the specificities of the Brucellacapt, Coombs, and SAT were 81.5, 96.2, and 100%, respectively; for the 412 control sera, the specificities were 99.0, 99.8, and 100%. The diagnostic efficiency (area below the receiver operating characteristic curve) of Brucellacapt was 0.987852 (95% confidence interval [CI], 0.95109 to 0.99286), very similar to the diagnostic efficiency of the Coombs test (0.97611; 95% CI, 0.94781 to 0.99146) and higher than that of SAT (0.91013; 95% CI, 0.86649 to 0.94317). The results of the Brucellacapt test were compared with those of the Coombs test (correlation coefficient, 0.956; P = 0.000) and SAT (correlation coefficient, 0.866; P = 0.000). The study shows very good correlation between the Brucellacapt and Coombs tests, with a high concordance between titers obtained in the two tests. Nevertheless, lower correlation and concordance were found between the Brucellacapt and Coombs tests when the results for titers of >/=1/160 were compared (0.692; P = 0.000). In acute brucellosis, the Brucellacapt and Coombs tests render positive titers of >/=1/160. When the titers are lower, they increase significantly in the following 30 days, despite the evolution of SAT titers. In contrast, Brucellacapt and Coombs titers are always high (>/=1/640) in brucellosis with long evolution, whether SAT titers are higher or lower than 1/160.

Adolescent↗
PubMed1999

Association of maternal short stature with stunting in Mexican children: common genes vs common environment.

OBJECTIVE: To evaluate the association between stunting in children and maternal short stature, controlling for potential environmental confounders. DESIGN: 1988 Mexico National Nutrition Survey. SETTING: Mexico SUBJECTS: The final sample size was 4663 pairs of children (<5 y) and their mothers (12-49 y) from a total of 13 236 surveyed houses. MAIN OUTCOME MEASURES: Stunting (height-for-age Z-scores <-2). RESULTS: The prevalence of stunting in children was 19%, and 10% of the mothers exhibited short stature (<145 cm). In the crude analysis, mothers with short stature were significantly more likely to have stunted children (odds ratio (OR)=4.0; 95% confidence interval (CI)=3.2-4.8; P-value <0.001). In a multiple logistic regression model the OR for child stunting was reduced, but remained significant OR=2.0; 95% CI=1.6-2.6; P-value <0.001) after adjustment for region, urban/rural residence, socio-economic status, household size, child age and presence of infection in the past 14 d, and maternal age, body mass index (BMI), and educational level. Adjusted ORs varied between regions (Mexico City, OR=3.9; North Mexico, OR=3. 1; Central Mexico, OR=2.0; South Mexico, OR=1.6. Comparison of crude vs adjusted estimates pointed to regional differences in the proportion of association between maternal and child short statures explained by environmental determinants. CONCLUSIONS: Maternal stature, reflecting her potential height and early environment, appeared to contribute to child height independently of the shared risk factors that could affect stature. Nonetheless, we could explain much of the association between stunting in children and maternal short stature by environmental factors, and part of the residual variability may be due to unmeasured determinants. Regional differences pointed to a predominance of environmental factors in explaining child stunting in poorer regions.

Adult↗
PubMed1999

Association of obesity with physical activity, television programs and other forms of video viewing among children in Mexico city.

OBJECTIVE: To assess the association of physical activity, television program viewing and other forms of video viewing with the prevalence of obesity among school children. DESIGN: Cross-sectional study. SUBJECTS: 712 children, 9-16 y old, from a low- and a middle-income town in the Mexico City area. MEASUREMENTS: Children completed a self administered questionnaire to assess time spent in physical activity and television viewing, and diet. Height weight and triceps skinfolds were measured. The outcome variable was obesity, and the covariates were hours of television programs and other video viewing, physical activity, energy intake, percentage of energy from fat, town of location of school, age, gender and perception of mother's weight status. RESULTS: Among 461 children with complete information, 24% were classified as obese. Children reported an average of 4.1 +/- 2.2 h/d watching television (2.4 +/- 1.5 h/d for TV programs and 1.7 +/- 1.5 h/d for video cassette recorder (VCR) or videogames), and 1.8 +/- 1.3 h/d in moderate and vigorous physical activities. Odds ratios (OR) of obesity were 12% higher for each hour of television program viewing per day (OR = 1.12, 95% confidence interval (CI) 1.02,-1.22), and 10% lower for each hour of moderate/vigorous physical activity per day (OR = 0.90, 95% CI 0.83-0.98), controlling for age, gender, town and perception of mother's weight status. Children in the middle-income town had higher adjusted odds of obesity (OR = 2.58, 95% CI 1.47-4.54). CONCLUSION: Physical activity and television viewing, but not VCR/videogames use, were related to obesity prevalence in Mexican children 9-16 y old.

Adolescent↗