Biomedical subjects

Rosa Hernández

Publications and source records attributed to Rosa Hernández.

6 recordsLinked to original sources

PubMed2006

Chemistry and the biological response against immunoisolating alginate-polycation capsules of different composition.

Implantation of microencapsulated cells has been proposed as a therapy for a wide variety of diseases. An absolute requirement is that the applied microcapsules have an optimal biocompatibility. The alginate-poly-L-lysine system is the most commonly applied system but is still suffering from tissue responses provoked by the capsule materials. In the present study, we investigate the biocompatibility of microcapsules elaborated with two commonly applied alginates, i.e. an intermediate-G alginate and a high-G alginate. These alginates were coated with poly-L-lysine (PLL), poly-D-lysine (PDL) and poly-L-ornithine (PLO). The main objective of this study is to determine the interaction of each alginate matrix with the different polycations and the potential impact of these interactions in the modulation of the host's immune response. To address these issues the different types of microcapsules were implanted into the peritoneal cavity of rats for I month. After this period the microcapsules were recovered and they were evaluated by different techniques. Monochromatised X-ray photoelectron spectroscopy (XPS) was performance and the degree of capsular recovery, overgrowth on each capsule, and the cellular composition of the overgrowth were evaluated by histology. Our results illustrate that the different observed immune responses are the consequence of the variations in the interactions between the polycations and alginates rather than to the alginates themselves. Our results suggest that PLL is the best option available and that we should avoid using PLO and PDL in its present form since it is our goals to produce capsules that lack overgrowth and do not induce an immunological response as such.

Alginates↗

PubMed2005

[Anthropometric characterization of an institutionalized elderly population from Caracas, Venezuela].

Most of the anthropometric standards are derived from adult populations but not from older subjects, so their use to evaluate the nutritional status in the elderly may not be the most appropriate. In this sense, the anthropometric characteristics and their relationship to sex and age in a cross-sectional sample of 809 Venezuelan subjects (370 males and 439 females), aged 60 to 102 years old, randomly selected from a elderly institution-alised population were studied. The results indicate that anthropometric variables show different degrees and signs of sexual dimorphism. Males presented higher stature, weight, waist and calf circumferences and higher bone diameters, while females have higher hip and thigh perimeters, and bigger trunk and extremities skinfolds. Independently of the changes observed in these variables with age, the difference spread between the sexes tends to stay and even to increase with age in the height and weight, in hip perimeter and in thigh and calf skinfolds; while, on the contrary, they attenuate in waist perimeter and in triceps, subescapular and suprailiac skinfolds. Males and females appear to be more similar for these variables in the advanced ages. In general, these results could be used as reference elements for similar researches in Venezuela, due to the low number of studies developed in the country in older populations

Aged↗

PubMed2005

[Nutritional status of institutionalized Venezuelan elderly].

With the aim of evaluating the nutritional status of institutionalized elders in different geriatric units of the metropolitan area of Caracas, 126 subjects with ages between 60 and 96 years old were evaluated. The Mini Nutritional Assessment was applied and were identified 48.4% individuals with nutritional risk, 5.6% malnourished and 46% without nutritional problems. Females presented higher prevalences of malnutrition and risk, while males presented an adequate nutritional state. By sex and age, females and males over 80 years presented a higher prevalence of malnutrition and risk when they were compared whit those younger. A low dayly liquid intake, a BMI equal or under of 23 kg/m2 and a limited physical performance were the items that presented the highest prevalence among the studied elders. In conclusion, the high prevalence of malnutrition risk in this population group, remarks the necessity to include into the global geriatric evaluation, a quick, simple and non-invasive instrument that allows to estimate the nutritional status of the elders.

Aged↗

PubMed2004

Two-dimensional reference map of Candida albicans hyphal forms.

We have set up an in vitro model of culture of Candida albicans fungal cells that mimics the physiological conditions found in human beings in order to carry out studies of host-pathogen interaction. Under these conditions, C. albicans undergoes dimorphic transition (yeast-hyphae); this morphological change has been proposed as a virulence factor for this fungus. C. albicans cytoplasmic extract from hyphae cells was analyzed by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) and a reference map was obtained. Protein identification was carried out by peptide mass fingerprinting or sequence tagging using a matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) or a MALDI-TOF/TOF mass spectrometer. A total of 106 spots, excised from 2-D gels, were analyzed. This resulted in the identification of 43 proteins involved in metabolism, 13 involved in transcription, protein synthesis, and fate, 8 involved in cell rescue, virulence, and defense, and 2 proteins of unknown function. This reference map is an important tool for future studies of protein differential expression after host-pathogen interaction.

Candida albicans↗

PubMed2003

Relation of neurological soft signs to nonverbal memory performance in obsessive-compulsive disorder.

Few studies have examined the relation between neurological soft signs (NSS) and neuropsychological performance in Obsessive-Compulsive Disorder (OCD). Thirty outpatients with primary OCD and 30 matched normal controls were administered the Cambridge Neurological Inventory and the Rey-Osterrieth Complex Figure Test (RCFT). A series of multiple regression models tested the relationship between NSS and performance on the RCFT. Patients presented significantly more neurological soft signs than controls on both sides of the body, and were impaired on the free recall and organization scores of the RCFT. Nonverbal memory deficits in OCD were predicted independently by organizational strategies during the copy condition of the RCFT, and neurological soft signs. There might be at least two variables independently mediating nonverbal memory deficits in OCD: (1) a cognitive organization and planning component, and (2) a complex motor regulatory component.

Adult↗

PubMed2003

[Selection of the more adequate prediction index to estimate the frame size a group of institutionalized and free living elderly in Venezuela. (Preliminary study)].

The objective of the study was to identify an easy to measure indicator of body frame size to allow refinement of anthropometric nutritional evaluation. Body dimensions and frame indices related to height, which might be potential frame size predictors in the elderly, were studied. In 307 subjects (163 women, 144 men) aged 60-99 years of whom 187 were institutionalized and 120 free-living outpatients, weight, height, mid-arm circumference; triceps, subscapular, midthigh and calf skinfolds; elbow, wrist, femur and biacromial widths, were measured. Body mass index, upper arm muscle area, upper arm fat area, fat percentage, sum of skinfolds and frame indices were calculated. Results were calculated in function of age, sex and life-style. Biacromial breadth, biacromial/height index, wrist breadth and wrist/height index gave variable correlations with indices of body mass and body fat. Femur breadth and femur/height index were significantly correlated with body fat indices. Elbow breadth, humerus/height index were not correlated to body fat indices, but were significantly correlated with weight, height and fat free mass. Elbow breadth and humerus/height index fulfilled most of the criteria of good predictors of body frame size in the group pf elderly studied.

Aged↗