Biomedical subjects
M T Ruiz
Publications and source records attributed to M T Ruiz.
Transient expression of Arabidopsis thaliana ascorbate peroxidase 3 in Nicotiana benthamiana plants infected with recombinant potato virus X.
We have explored the transient over-expression of Arabidopsis thaliana ascorbate peroxidase 3 (APX3) in Nicotiana benthamiana using a viral vector based on the potato virus X (PVX). Plants infected with a PVX:APX3 hybrid had a similar progression of viral particles compared to control plants infected with a PVX:GFP hybrid, indicating that infection was not affected by the over-expression of heterologous APX3. Our results also showed that in PVX:APX3-infected plants, the hybrid virus directed a high level of APX3 expression and the recombinant protein was functional, as inferred from the higher APX activity compared to mock and PVX:GFP hybrid-infected plants. The PVX recombinant expression system used is a simple and quick method for transient expression of heterologous APXs, which are expected to suffer specific processing in plant cells.
Copy number of P elements, KP/full-sized P element ratio and their relationships with environmental factors in Brazilian Drosophila melanogaster populations.
The P transposable element copy numbers and the KP/full-sized P element ratios were determined in eight Brazilian strains of Drosophila melanogaster. Strains from tropical regions showed lower overall P element copy numbers than did strains from temperate regions. Variable numbers of full-sized and defective elements were detected, but the full-sized P and KP elements were the predominant classes of elements in all strains. The full-sized P and KP element ratios were calculated and compared with latitude. The northernmost and southernmost Brazilian strains showed fewer full-sized elements than KP elements per genome, and the strains from less extreme latitudes had many more full-sized P than KP elements. However, no clinal variation was observed. Strains from different localities, previously classified as having P cytotype, displayed a higher or a lower proportion of KP elements than of full-sized P elements, as well as an equal number of the two element types, showing that the same phenotype may be produced by different underlying genomic components of the P-M system.
Doing things together: adolescent health and family rituals.
STUDY OBJECTIVES: (1) To describe the union and life cycle of family rituals, such as specific habits of sharing daily meals, special events or other family activities, and (2) to analyse the relation between the practice of family rituals and the use by adolescents of mental health related ambulatory care services. DESIGN: A cross sectional study. SETTING: A public mental health care outpatient clinic, secondary educational centres and Alicante University (School of Social Workers and Nursing School) in Spain. PARTICIPANTS: A total of 282 living at home youngsters were included in the study. The case group, n=82, was sequential and consecutively drawn from the first consultation in a public mental health outpatient clinic attending a downtown area of Alicante. The comparison group (n=213) was made up of a conglomerate from various educational centres in the same metropolitan area. MAIN RESULTS: There was a significant difference (p=0.027) between the frequencies with which parents ate together with their offspring in the two study groups. The families of the adolescents comparison group significantly (p=0.00007) shared more family celebrations than the case group-also, the extended family was included more frequently. Moreover, differences between both groups were found in other activities and situations-adolescents in the case group reported carrying out less family activities than the adolescents in the comparison group (p=0.00001). The lower level of satisfaction in the adolescent's perception of family function led to a higher probability of presenting mental health complaints (p=0.00001). CONCLUSIONS: The youngsters with mental health complaints ate less frequently with both parents than the youngsters in the comparison group. They also shared less activities and practised less family rituals-union and life cycle-than the families of the youngsters in the comparison group, and showed a lower level of satisfaction in perceived family function.
Fighting against Chagas' disease in the Guarani communities in Bolivia.
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The widening social class gap of preventive health behaviours in Spain.
As a way of forecasting future evolution of inequalities in disease burden and mortality, trends in preventive health behaviours by social class were examined. Using the Spanish National Health Survey from 1987 to 1997 the evolution of the Health Practices Index (smoking, alcohol consumption, physical exercise, sleep hours and the Quetelet index) is described for the Spanish non-institutionalised adult population. In the last 10 years the disadvantaged population of Spain (social class groups IV and V) has not opted for healthier behavioural choices. On the contrary the Health Practices Index figures have worsened during the study period. Conversely, the more affluent groups (social class groups I, II and III) have exhibited a net gain in the index. Due to this, an increase in the existing gap in health inequalities in Spain in terms of morbidity and mortality can be forecast for the near future. As time trends of a summary indicator of preventive health behaviours by social class have not been described in other countries, a replication of this study in different cultural, social and economic milieus could produce valuable information.
Rethinking the map for health inequalities.
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Empowering the deaf. Let the deaf be deaf.
Deafness is often regarded as just a one and only phenomenon. Accordingly, deaf people are pictured as a unified body of people who share a single problem. From a medical point of view, we find it usual to work with a classification of deafness in which pathologies attributable to an inner ear disorder are segregated from pathologies attributable to an outer/middle ear disorder. Medical intervention is thus concerned more with the origin, degree, type of loss, onset, and structural pathology of deafness than with communicative disability and the implications there may be for the patient (mainly dependency, denial of abnormal hearing behaviour, low self esteem, rejection of the prosthetic help, and the breakdown of social relationships). In this paper, we argue that hearing loss is a very complex phenomenon, which has many and serious consequences for people and involves many factors and issues that should be carefully examined. The immediate consequence of deafness is a breakdown in communication whereby the communicative function needs to be either initiated or restored. In that sense, empowering strategies--aimed at promoting not only a more traditional psychological empowerment but also a community one--should primarily focus on the removal of communication barriers.
OBA/Ku86: DNA binding specificity and involvement in mammalian DNA replication.
Ors-binding activity (OBA) was previously semipurified from HeLa cells through its ability to interact specifically with the 186-basepair (bp) minimal replication origin of ors8 and support ors8 replication in vitro. Here, through competition band-shift analyses, using as competitors various subfragments of the 186-bp minimal ori, we identified an internal region of 59 bp that competed for OBA binding as efficiently as the full 186-bp fragment. The 59-bp fragment has homology to a 36-bp sequence (A3/4) generated by comparing various mammalian replication origins, including the ors. A3/4 is, by itself, capable of competing most efficiently for OBA binding to the 186-bp fragment. Band-shift elution of the A3/4-OBA complex, followed by Southwestern analysis using the A3/4 sequence as probe, revealed a major band of approximately 92 kDa involved in the DNA binding activity of OBA. Microsequencing analysis revealed that the 92-kDa polypeptide is identical to the 86-kDa subunit of human Ku antigen. The affinity-purified OBA fraction obtained using an A3/4 affinity column also contained the 70-kDa subunit of Ku and the DNA-dependent protein kinase catalytic subunit. In vitro DNA replication experiments in the presence of A3/4 oligonucleotide or anti-Ku70 and anti-Ku86 antibodies implicate Ku in mammalian DNA replication.
Oct-1 enhances the in vitro replication of a mammalian autonomously replicating DNA sequence.
A 186-base pair fragment of ors8, a mammalian autonomously replicating DNA sequence isolated by extrusion of nascent monkey DNA in early S phase, has previously been identified as the minimal sequence required for replication function in vitro and in vivo. This 186-base pair fragment contains, among other sequence characteristics, an imperfect consensus binding site for the ubiquitous transcription factor Oct-1. We have investigated the role of Oct-1 protein in the in vitro replication of this mammalian origin. Depletion of the endogenous Oct-1 protein, by inclusion of an oligonucleotide comprising the Oct-1 binding site,inhibited the in vitro replication of p186 to approximately 15-20% of the control, whereas a mutated Oct-1 and a nonspecific oligonucleotide had no effect. Furthermore, immunodepletion of the Oct-1 protein from the HeLa cell extracts by addition of an anti-POU antibody to the in vitro replication reactioninhibited p186 replication to 25% of control levels. This inhibition of replication could be partially reversed to 50-65% of control levels, a two- to threefold increase, upon the addition of exogenous Oct-1 POU domain protein. Site-directed mutagenesis of the octamer binding site in p186 resulted in a mutant clone, p186-MutOct, which abolished Oct-1 binding but was still able to replicate as efficiently as the wild-type p186. The results suggest that Oct-1 protein is an enhancing component in the in vitro replication of p186 but that its effect on replication is not caused through direct binding to the octamer motif.
An EXCEL template for calculation of enzyme kinetic parameters by non-linear regression.
MOTIVATION: An EXCEL template has been developed for the calculation of enzyme kinetic parameters by non-linear regression techniques. The tool is accurate, inexpensive, as well as easy to use and modify. AVAILABILITY: The program is available from http://www.ebi.ac.uk/biocat/biocat.html CONTACT: agustin. hernandez@bio.kuleuven.ac.be
A two way view of gender bias in medicine.
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Posttranslational regulation of nitrogenase activity by fixed nitrogen in Azotobacter chroococcum.
Using anti-(Fe protein) antibody raised against the Fe protein of the photosynthetic bacterium Rhodospirillum rubrum, it was found that the Fe protein component of nitrogenase (EC 1.18.2.1) from Azotobacter chroococcum cells subjected to an ammonium shock, and hence with an inactive nitrogenase, appeared as a doublet in Western blot analysis of cell extracts. The Fe protein incorporated [32P]phosphate and [3H]adenine in response to ammonium treatment, and L-methionine-DL-sulfoximine, an inhibitor of glutamine synthetase (L-glutamate: ammonia ligase (ADP forming), EC 6.3.1.2), prevented Fe protein from inhibition and radioisotope labelling. These results support that A. chroococcum Fe protein is most likely ADP-ribosylated in response to ammonium. After ammonium treatment, when in vivo activity was completely inhibited, Fe-protein modification was still increasing. This suggests the existence of another mechanism of nitrogenase inhibition faster than Fe-protein modification. When ammonium was intracellularly generated instead of being externally added, as occurs with the short-term nitrate inhibition of nitrogenase activity observed in A. chroococcum cells simultaneously fixing molecular nitrogen and assimilating nitrate, a covalent modification of the Fe protein was likewise demonstrated.
[Sexual myths in an adult population].
BACKGROUND: Clinical observation ratifies the existence of commonly accepted erroneous beliefs (EB) in relation to sexuality. In the health care sector, reinforcing factors of these beliefs are the professionals who are not specifically trained to manage, or detect the same in addition to the variability of the criteria available on sexual health care. METHODS: The EB on sexuality were studied in 260 individuals (14-18 years) who are users of primary health care services. Four consultation offices of General Medicine were randomly selected, one by health care center (Area 20, Valencian Community, Spain). Subsequently, a structured interview was given to the users of these consultations over the period of one day. The interviews were carried out after receiving consent and guarantee of confidentiality. On the other hand, the results were compared with those previously obtained from the 44 health care professionals (HCP). The results are reported, the proportions compared (chi-square) to determine differences according to age, sex and level of education and the odds ratio was calculated to determine the probability of participation in EB according to sex. The response rate in users was 97.4% and is HCP 58%. RESULTS: The proportion of EB ranged from 16.9% who believed coitus as the only "normal" sexual relationship and 63.8% who believed in the existence of two types of female orgasm. Depending on the beliefs, statistically significant differences were observed according to age (from p = 0.03 to p < 0.0000) and the level of education (from p = 0.01 to p < 0.0000) and between the user adult population and the HCP (from p = 0.01 to p < 0.0000). CONCLUSIONS: There are numerous erroneous beliefs regarding sexuality in both primary health care users and, to a lesser extent, Spanish health care professionals. The influence of moral criteria, centered on reproduction, and prevalent sociocultural norms and values is of note. It was found that erroneous beliefs do not decrease with the educational level, but rather, change.
Cofractionation of HeLa cell replication proteins with ors-binding activity.
Ors (origin enriched sequence) 8 is a mammalian autonomously replicating DNA sequence previously isolated by extrusion of nascent monkey (CV-1) DNA in early S phase. A 186 bp fragment of ors 8 has been identified as the minimal sequence required for origin function, since upon its deletion the in vivo and in vitro replication activity of this ors is abolished. We have fractionated total HeLa cell extracts on a DEAE-Sephadex and then on a Affi-Gel Heparin column and identified a protein fraction that interacts with the 186 bp fragment of ors 8 in a specific manner. The same fraction is able to support the in vitro replication of ors 8 plasmid. The ors binding activity (OBA) present in this fraction sediments at approximately 150 kDa in a glycerol gradient. Band-shift elution experiments of the specific protein-DNA complex detect by silver-staining predominantly two protein bands with molecular weights of 146 kDa and 154 kDa, respectively. The fraction containing the OBA is also enriched for polymerases alpha and delta, topoisomerase II, and replication protein A, (RP-A).
Cruciform DNA binding protein in HeLa cell extracts.
We have analyzed by band-shift assays HeLa cell protein-DNA interactions on a stable cruciform DNA molecule. The stable cruciform was formed by heteroduplexing the HindIII-SphI fragment of SV40 virus DNA that contains the origin of replication with a derivative mutant containing a heterologous substitution at the central inverted repeat. We have identified a novel binding activity in HeLa cell extracts with specificity for the cruciform-containing DNA and no apparent sequence specificity. The activity is protein-dependent, void of detectable nuclease activity, and distinct from that reported for HMG1. A cruciform binding protein (CBP) with an apparent molecular weight of 66 kDa was enriched from HeLa cell extracts. In addition to the CBP, we have detected sequence-specific binding activities to sites proximal to the cruciform. Binding to one such site is increased in the cruciform-containing heteroduplex DNA by comparison to its linear homoduplex counterpart, suggesting transmission of structural effects by the stem-loops to their local environment.
[Health care according to the sex of patients].
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[Disturbances in sexual function: analysis of conditioning factors of an effective health care center].
BACKGROUND: With the aim of promoting activities related with sexual problems of the population in the health care area of the province of Alicante (Spain), the following objectives were set to the teams of primary health care: to know the opinion of the professionals concerning the most frequent reasons for consultation related with sexuality, establish opinions on their knowledge and educational requirements in this area, decrease sexual myths, strengthen the habit of registration of information on sexual behavior and problems related with the sexuality of the users and increase the frequency of derivating these problems to specialists. METHODS: Information was collected with a self applied survey on variables related with the above objectives. Four seminars were then developed on human sexual response, sexologic interview, sexual dysfunction and sexual therapy from the results obtained. One year thereafter, an evaluation was carried out in which the initial survey was reapplied. RESULTS: Fifty-eight percent of the 77 primary care professionals responded to the survey adequately in the initial phase. In their opinion the first three causes for consultation are impotence (13%), dispareunia (12%) and sexual disturbances related with chronic diseases (11%). The perception of their knowledge concerning the subjects covered in the seminars was slight with training in this area being clearly required. Eighty-nine percent were in favor of the collection of information on sexuality in health care files in contrast to 20% who reported to do so. From the initial to the final evaluation a decrease was seen in the direct intervention of the primary health care teams and an increase in derivations to specialists, which was of interest since around 20% of the professionals have erroneous beliefs on sexuality, varying according to the professions. CONCLUSIONS: The low level of knowledge and abilities perceived, the need for education, possession of the erroneous beliefs of the health care professionals surveyed and the passive behavior but positive attitude towards the sexual problems of the population reconfirm the importance of adequate continued training to health care professionals, particularly to those of primary health care since they are the ideal suppliers of assistance to sexual problems.