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Biomedical subjects

R Araya

Publications and source records attributed to R Araya.

At least 19 recordsLinked to original sources
PubMed2006

The thermolabile variant of MTHFR is associated with depression in the British Women's Heart and Health Study and a meta-analysis.

Low dietary folate intake has been implicated as a risk factor for depression. However, observational epidemiological studies are plagued by problems of confounding, reverse causality and measurement error. A common polymorphism (C677T) in MTHFR is associated with methyltetrahydrofolate reductase (MTHFR) activity and circulating folate and homocysteine levels and offers insights into whether the association between low folate and depression is causal. We genotyped this polymorphism in 3,478 women in the British Women's Heart and Health Study. In these women, we looked at the association between genotype and three indicators of depression; ever diagnosed as depressed, currently taking antidepressants and the EuroQol mood question. We also carried out a systematic review and meta-analysis of all published studies which have looked at the association between MTHFR C677T genotype and depression. In the British Women's Heart and Health Study, we found evidence of an increased risk of ever being diagnosed as depressed in MTHFR C677T TT individuals compared with CC individuals, odds ratio (OR) 1.35(95% CI: 1.01, 1.80). Furthermore, we identified eight other studies, which have examined the association between depression and MTHFR C677T. We were able to include all of these studies in our meta-analysis together with our results, obtaining an overall summary OR of 1.36 (95% CI: 1.11, 1.67, P=0.003). Since this genotype influences the functioning of the folate metabolic pathway, these findings suggest that folate or its derivatives may be causally related to risk of depression.

Aged↗
PubMed2003

Human spermatozoa motility analysis in a Ringer's solution containing cupric ions.

The ability of cupric ions to immobilize human spermatozoa was assessed in vitro using an optical microscope. A Ringer's solution containing human spermatozoa and three cupric ion concentrations of 8 x 10(-8) mol/L, 8 x 10(-6) mol/L and 8 x 10(-5) mol/L were tested. The higher cupric ion concentrations (8 x 10(-5) mol/L and 8 x 10(-6) mol/L) significantly reduced spermatozoa motility after about 20 min. However, with the lower cupric ion concentration tested (8 x 10(-8) mol/L), also for 20-min experimentation, the reduction in motility was more limited.

Copper↗
PubMed2003

Education and income: which is more important for mental health?

STUDY OBJECTIVE: To assess which indicators of socioeconomic status are associated with an increased prevalence of common mental disorders. DESIGN: Cross sectional household survey. SETTING: Santiago, Chile. PARTICIPANTS: Random sample of adults aged 16-65 residing in private households. MAIN RESULTS: Less education (odds ratio 2.44, 95% confidence intervals 1.50 to 3.97), a recent income decrease (odds ratio 2.14, 1.70 to 2.70), and poor housing (odds ratio 1.53, 1.05 to 2.23), were the only socioeconomic status variables that remained significantly associated with an increased prevalence of common mental disorders after adjustments. The prevalence of common mental disorders was also higher among people with manual unskilled occupations, overcrowded housing, and lower per capita income but these associations disappeared after adjustment for other explanatory and confounding variables. CONCLUSIONS: There is a strong, inverse, and independent association between education and common mental disorders. However, income was not associated with the prevalence of common mental disorders, after adjusting for other socioeconomic variables. Similar results have been found in other Latin American studies but British studies tend to find the opposite, that income but not education is associated with common mental disorders. Understanding the impact of socioeconomic factors on mental health requires research in poor as well as rich countries.

Adolescent↗
PubMed2002

Yeast two-hybrid screening using constitutive-active caspase-7 as bait in the identification of PA28gamma as an effector caspase substrate.

Caspase-3 and -7 represent executioner/effector caspases that directly cause apoptotic morphological changes by cleaving various death substrates. The substrates for caspases generally interact with active caspases, but not with inactive zymogens of caspase or procaspases. Here, to isolate proteins that interact with caspase-7, we established a yeast two-hybrid screening system using reversed-caspase-7, a constitutive active mutant of caspase-7 as a bait plasmid. Screening of an adult brain cDNA library led to isolation of proteasome activator 28 subunit, PA28gamma. In vitro translates of PA28gamma were cleaved by both recombinant caspase-3 and -7. Mutagenesis of potential cleavage site DGLD80 to EGLE80 completely abolished caspase-mediated cleavage. Moreover, endogenous PA28gamma was cleaved during not only Fas-induced apoptosis of HeLa cells, but also cisplatin-induced cell death of MCF7 cells, which are devoid of caspase-3. These findings indicate that PA28gamma is an endogenous substrate for caspase-3 and -7 and that yeast two-hybrid screening using reversed-caspase is a novel and useful approach to clone substrates for effector caspases.

Apoptosis↗
PubMed2001

Classification, disability and the public health agenda.

Depression is a common and disabling illness. For some time the disability has been relatively neglected by those interested in public health. Public health priorities have largely been determined by statistics on mortality. The World Health Organization has argued for some time that public health should be concerned with 'adding life to years' as well as 'adding years to life'. This article will argue that depression should be a key priority for public health research.

Anxiety↗
PubMed2001

Common mental disorders in Santiago, Chile: prevalence and socio-demographic correlates.

BACKGROUND: There have been relatively few surveys in Latin America that have attempted to estimate the prevalence of psychiatric morbidity in private households. AIMS: To determine the prevalence of common mental disorders and socio-demographic correlates among adults from Santiago, Chile. METHOD: Cross-sectional survey of private households with a probabilistic sampling design was used. Common mental disorders were measured using the Clinical Interview Schedule-Revised (CIS-R). RESULTS: Three thousand eight hundred and seventy adults were interviewed. Twenty-five per cent were CIS-R cases and 13% met criteria for an ICD-10 diagnosis. Low education, female gender, unemployment, separation, low social status and lone parenthood were associated with a higher prevalence. CONCLUSIONS: Prevalence rates were higher than those found in urban areas of Great Britain, both for ICD-10 diagnoses and 'non-specific neurotic disorders'. Similar socio-demographic factors were associated with an increased prevalence of common mental disorders in Chile as in the UK. There is a need to unify methodologies to be able to compare results internationally.

Adolescent↗
PubMed2001

Two-year follow-up after a randomised controlled trial of self- and clinician-accompanied exposure for phobia/panic disorders.

BACKGROUND: Long-term follow-up has rarely been reported after self-exposure therapy for phobias. AIMS: Completion of such a follow-up. METHOD: Two-year follow-up was achieved in 68 (85%) of 80 patients with phobias who had completed a previous 14-week randomised controlled trial comparing therapist-accompanied self-exposure, self-exposure or self-relaxation. Measures were self-reported ratings of symptoms, satisfaction and use of other treatment. RESULTS: Improvement at week 14 was maintained 2 years later. Clinician-accompanied exposure and self-exposure did not differ on any measure. Compliance with self-exposure homework during weeks 0-8 predicted more improvement 2 years later. Patients who failed to improve with relaxation by week 14 improved after subsequent crossover to exposure. A need for more treatment for their phobias was still felt by 33 patients (49%). CONCLUSIONS: Patients with phobias maintained their improvement to 2-year follow-up after the end of self-exposure therapy.

Adult↗
PubMed1999

Women, poverty and common mental disorders in four restructuring societies.

BACKGROUND: Poverty and female gender have been found to be associated with depression and anxiety in developed countries. The rationale behind this paper was to bring together five epidemiological data sets from four low to middle income countries to examine whether key economic and development indicators such as income and poor education, and female gender, were associated with common mental disorders. METHOD: The paper is based on five datasets: three based on primary care attenders in Goa, India; Harare, Zimbabwe and Santiago, Chile; and two based on community samples in Pelotas, Brazil and Olinda, Brazil. All five studies estimated prevalence of common mental disorders along with variables to measure economic deprivation and education. FINDINGS: In all five studies, female gender, low education and poverty were strongly associated with common mental disorders. When income was divided into tertiles, with the lowest tertile as a reference value, there was a significant trend for reduced morbidity for the lower two tertiles. DISCUSSION: These findings have considerable implications since the rapid economic changes in all four societies have been associated with rising income disparity and economic inequality. Examples of population based prevention strategies based on increasing the proportion of those who complete schooling and on high-risk strategies such as providing loan facilities to the impoverished are potential outcomes of these findings. Development agencies who focus on women as a priority group have failed to recognize their unique vulnerability to common mental disorders and need to reorient their priorities accordingly.

Adult↗
PubMed1998

Hypoxia induces apoptosis in human neuroblastoma SK-N-MC cells by caspase activation accompanying cytochrome c release from mitochondria.

We have attempted to elucidate the mechanism of apoptotic cell death induced by hypoxia (very low oxygen conditions) in neuronal cells. Human neuroblastoma SK-N-MC cells under hypoxic conditions resulted in apoptosis in a time-dependent manner estimated by DNA fragmentation assay and nuclear morphology stained with fluorescent chromatin dye. Pretreatment with Z-Asp-CH2-DCB, a caspase inhibitor, suppressed the DNA ladder in response to hypoxia in a concentration-dependent manner. An increase in caspase-3-like protease (DEVDase) activity was observed during apoptosis, but no caspase-1 activity (YVADase) was detected. To confirm the involvement of caspase-3 during apoptosis, Western blot analysis was performed using anti-caspase-3 antibody. The 20- and 17-kDa proteins, corresponding to the active products of caspase-3, were generated in hypoxia-challenged lysates in which processing of the full length form of caspase-3 was evident. With a time course similar to this caspase-3 activation, hypoxic stress caused the cleavage of PARP, yielding an 85-kDa fragment typical of caspase activity. In addition, caspase-2 was also activated by hypoxia, and the stress elicited the release of cytochrome c into the cytosol during apoptosis. These results suggest that caspase activation and cytochrome c release play roles in hypoxia-induced neuronal apoptosis.

Apoptosis↗
PubMed1998

The comparison of latent variable models of non-psychotic psychiatric morbidity in four culturally diverse populations.

BACKGROUND: Factor analysis has been employed to identify latent variables that are unifying constructs and that parsimoniously describe correlations among a related group of variables. Confirmatory factor analysis is used to test hypothesized factor structures for a set of variables; it can also, as in this paper be used to model data from two or more groups simultaneously to determine whether they have the same factor structure. METHOD: Non-psychotic psychiatric morbidity, elicited by the Revised Clinical Interview Schedule (CIS-R), from four culturally diverse populations was compared. Confirmatory factor analysis was employed to compare the factor structures of CIS-R data sets from Santiago, Harare, Rotherhithe and Ealing. These structures were compared with hypothetical one and two factor (depression-anxiety) models. RESULTS: The models fitted well with the different data sets. The depression-anxiety model was marginally superior to the one factor model as judged by various statistical measures of fit. The two factors in depression-anxiety model were, however, highly correlated. CONCLUSIONS: The findings suggest that symptoms of emotional distress seem to have the same factor structure across cultures.

Adolescent↗
PubMed1998

[Common mental disorders, depression and public health].

Common Mental Disorders (CMD), particularly depressive disorders, are problems of public health importance and it would seem appropriate to approach them from a public health point of view. In this paper only psychosocial aspects are dealt with, because biological factors are less important in the pathogenesis of CMD. Although there are significant associations between socioeconomic variables and CMD, the association between poverty and CMD seems to be one of the most robust. There is good evidence that low income is associated with CMD, and this relationship may be causal. There is therefore a possibility that changes in social and economic policy that would reduce poverty might also reduce the prevalence of CMD. Future research should try to unravel the mechanisms and causal factors that underlie these common and disabling disorders.

Depression↗
PubMed1996

Association of Aeromonas hydrophila and Vibrio alginolyticus with Larval Mortalities of Scallop (Argopecten purpuratus)

A bacteriological study was carried out in a hatchery of Argopecten purpuratus located in northern Chile which had been affected by severe larval mortalities. The phenotypic characterization of the bacterial strains revealed that Vibrio alginolyticus was the predominant species isolated in the majority of samples taken from the different units of the hatchery (microalgae, swimming larvae, seawater of larval culture tanks, and a reservoir tank of 50-μm filtered seawater). However, the bacterial population of dying larvae was composed of only Aeromonas hydrophila strains which proved to be resistant to most of the chemotherapeutic agents tested. The bioassays conducted to evaluate the effect of these bacteria on larval survival showed that all of the isolated Vibrio and Aeromonas strains possessed a high degree of pathogenicity, since they produced dying larvae on concentrations ranging from 5.5 x 10(4) to 5.5 x 10(2) cells/ml. The possible virulence mechanism of these bacteria is discussed, as well as the potential use of drugs to prevent larval mortalities.

Journal Article↗
PubMed1995

Validation of the Edinburgh Postnatal Depression Scale (EPDS) in Chilean postpartum women.

A validity study of the Edinburgh Postnatal Depression Scale (EPDS) against the Research Diagnostic Criteria (RDC) was carried out on a sample of women attending a health care center in Santiago. One hundred and eight middle-class mothers filled in the EPDS and were later interviewed by the main author using the Psychiatric Assessment Schedule (PAS). The internal consistency of the EPDS was reasonably good (Cronbach's alpha 0.77). Validity coefficients for the scale were calculated to determine the best case/non-case threshold which was found to be 9/10. Sensitivity, specificity and positive predictive value for this threshold were 100%, 80% and 37% correspondingly. The same best cut-off point (9/10) was found by other Chilean investigators in a sample of working-class women. The EPDS was shown to be a useful screening instrument for postnatal depression in these settings.

Adult↗
PubMed1995

[Prevalence of postpartum depression and associated factors in Santiago, Chile].

The aim of this study was to estimate the prevalence and factors associated to postpartum depression (PPD) in a sample of women attending clinics representative of different socioeconomic levels in Santiago. A total of 542 mothers selected from five health centres filled in the Edinburgh Postnatal Depression Scale which was used as the diagnostic criteria, a score of 10 and above being considered diagnostic of depression. Based in our findings, the prevalence of PPD would be 36.7% after adjusting for socioeconomic distribution in Santiago. An inverse relationship was found between socioeconomic status and prevalence of PPD. Mothers with lower incomes had a three-fold increase in prevalence of PPD in comparison to mothers with higher incomes. Single mothers (unmarried, separated and widows) were twice more likely to be cases of PPD.

Adolescent↗
PubMed1994

Psychiatric morbidity in primary health care in Santiago, Chile. Preliminary findings.

BACKGROUND: The aims were to determine the prevalence of psychiatric morbidity among primary care attenders in a poor suburb of Santiago and to study the relationship with health service use. METHOD: A cross-sectional survey was made of 163 consecutive attenders to a primary care clinic. RESULTS: Eleven per cent of the sample gave a psychological reason for consultation and the prevalence of psychiatric morbidity was 53%, defined using the revised Clinical Interview Schedule. Women and those of lower socio-economic status were at higher risk. Physicians recognised 14% of the psychiatric morbidity. Attenders with psychiatric morbidity consulted more frequently. CONCLUSIONS: There is a need to improve the recognition and management of psychiatric morbidity in primary care in Chile and other less developed countries. This could lead to the more efficient use of scarce health care resources in primary care.

Adult↗
PubMed1994

Ion dependence of resting membrane potential of rat spermatids.

The membrane potential of rat spermatids was estimated as -22 +/- 2 mV (mean +/- SEM) using three independent methods: using oxonol as a fluorescent membrane potential sensitive probe, from the passive distribution of hydrogen ions and from whole-cell patch-clamp records. The estimated permeability ratios PK+:PCl- and PNa+:PCl- of the plasma membrane of rat spermatids were 1.0 and 0.3, respectively. These data indicate that the high luminal K+ concentration found in seminiferous tubules could partially close voltage-sensitive calcium channels in these cells.

Animals↗
PubMed1993

[Depression in pregnancy and puerperium: study of risk factors].

This study was aimed at determining risk factors associated to depression in pregnancy and/or the puerperium. By means of both observer-rated, and self-rated scales a 108-expectant mother sample was assessed by the co-investigators, interviewed by the principal investigator later on. The Psychiatric Assessment Schedule was used to obtain an RDC diagnosis. The same procedure was repeated 2 to 3 months after delivery. A greater exposure to life events, prior consultation for emotional problems as well as economic difficulties arising of late were all associated to depression in pregnancy and the puerperium. Getting separated from significant persons in a woman's life, and/or difficult relationships with either husband or mother have been strongly associated to depression at both periods. As regards puerperium depression, several associations directly related to childbirth (having had a low-weight baby) or the postnatal period (lactation problems) were detected. Anxiety and depressive symptoms during pregnancy have been also clearly linked to postpartum depression. The predictive value of such risk factors is discussed. It is suggested that questions on these factors should be included into ordinary health assessments of both pregnant and puerperal women.

Adult↗