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Biomedical subjects

M Barrera

Publications and source records attributed to M Barrera.

At least 55 records · Page 3Linked to original sources
PubMed1990

[Entero-urinary fistula. A study of 22 cases].

We performed a retrospective study on 22 patients with entero-urinary fistulas that had been diagnosed and treated at the Hospital Clinico i Provincial in Barcelona during the period spanning 1981-1988. Fistulas were classified according to the organs or parts with which they communicated. Among the important etiogenic conditions were diverticular disease of colon. Crohn's disease, actinic lesions, trauma and xanthogranulomatous pyelonephritis. The clinical manifestations were principally urological in the form of recurrent urinary infection and terminal pneumaturia. The most useful diagnostic techniques were cystoscopy; serial voiding cystourethrography (SVCU), retrograde urethrography and pyelography. Treatment was by surgery in all cases. Diversion procedures or surgical excision of the fistulous tract were performed as warranted by each case. The etiopathogenic, morphological and therapeutical aspects of vesico-enteric fistulas are discussed.

Adolescent↗
PubMed1989

Long-term follow-up after unilateral nephrectomy and radiotherapy for Wilms' tumour.

Twenty-nine patients who had had unilateral nephrectomy for Wilms' tumour in one hospital were known to have survived more than 12 years. Sixteen agreed to attend for clinical review, of whom 14 had estimation of serum creatinine, 24-h urine protein excretion and endogenous creatinine clearance. The follow-up period was 13-26 years (median 17 years). All but one had had radiotherapy and all had chemotherapy (actinomycin D, 16; vincristine, 5). Some degree of kyphoscoliosis was present in all except the patient who did not receive radiotherapy. Four patients had diastolic blood pressure 90 mmHg or greater. Two patients had mild proteinuria (392, 361 mg/day). Serum creatinine ranged from 53 to 125 mumol/l and endogenous creatinine clearance ranged from 39 to 173 ml/min (median 81, mean 89). Of the 7 patients who were 20-26 years post-nephrectomy, 2 were hypertensive and 1 had elevated urinary protein excretion. We conclude that the long-term prognosis of unilateral nephrectomy in childhood is good.

Adolescent↗
PubMed1989

Positive and negative social ties among older adults: measurement models and the prediction of psychological distress and well-being.

The factor structure of positive and negative social ties was studied among 246 older adults who were either recently physically disabled, recently conjugally bereaved, or matched controls. Covariance structure analyses were carried out on a network measure to determine whether positive and negative social ties represent independent domains of social experience, and to assess the degree to which their structure is invariant across groups undergoing major loss transitions. Positive and negative social ties were found to be independent and there was substantial similarity in their factor structure across the three groups. Hierarchical regression analyses revealed that, whereas positive social ties were related to psychological well-being, negative social ties were predictive of both psychological well-being and distress. These results demonstrate the importance of assessing both positive and negative ties in explaining the psychological adjustment of older adults.

Affective Symptoms↗
PubMed1988

Properties of the Beck Depression Inventory as a screening instrument for adolescent depression.

The utility of the Beck Depression Inventory (BDI) for identifying Major Depressive Episode was assessed with two samples of adolescents, 65 psychiatric hospital inpatients and 49 secondary school students. Diagnoses based on the Child Assessment Schedule served as criteria. With the school sample, a BDI screening score of 16 resulted in 100% sensitivity and 93.2% specificity. For the inpatient sample, a cutoff of 11 yielded a sensitivity of 81.5% and specificity of 52.6%. There was evidence of the BDI's convergent and discriminant validity for both samples. The results were consistent with the assertion that Major Depressive Episode is a sufficiently distinct diagnostic category in adolescence to be detected by a screening measure such as the BDI.

Adolescent↗
PubMed1988

Breast-feeding and the return to ovulation in Durango, Mexico.

Twenty-nine breast-feeding mothers and 10 non-breast-feeding postpartum comparison mothers from a rural area of Mexico were followed longitudinally until ovulation resumed. A simple set of guidelines is described involving three obvious milestones for the breast-feeding mother to safely use the natural contraceptive benefit of breast-feeding. Those milestones are: the first vaginal bleeding episode, the initiation of supplementation, and the child's monthly birthday. In the absence of bleeding and supplementation, 100% of breast-feeding mothers remained anovular for 3 months postpartum, 96% for 4 months, 96% for 5 months, and 96% for 6 months. This suggests that, if a mother understands these three conditions, she can use breast-feeding alone as effectively as modern family planning methods for the prevention of pregnancy.

Adolescent↗
PubMed1987

Divorcing mothers and social support: testing the specificity of buffering effects.

The circumstances under which social support buffers the negative effects of stress have been a subject of much research. The hypothesis that social support is effective only when it matches the needs elicited by particular stressors was studied in a sample of divorcing mothers. Predictions were made regarding which types of support (Parenting, Emotional, and Tangible) would buffer the effects of Parenting, Social, and Tangible stress on depressive symptoms and on general psychological distress of divorcing mothers. Results did not support the specificity of social support buffering effects, though the stress and support scales often showed direct relationships to criterion measures. Implications were discussed for the assessment of support with multiple models, for future research designs, and for planning prevention programs to meet the needs of divorcing mothers.

Adult↗
PubMed1986

Occupational stress, social support, and burnout among correctional officers.

Three alternative models of the role of workplace social support in ameliorating the effect of occupational stress on burnout symptoms were tested. Correctional officers (N = 166) completed a variety of questionnaire measures of job stress, the Inventory of Socially Supportive Behaviors, and the Maslach Burnout Inventory. Analyses showed no support for either the direct or buffering models of social support. Rather, the data were consistent with the indirect model of social support in the workplace. Among the job stress indices, role ambiguity, work load, and direct contact with inmates were found to be independent predictors of burnout symptomatology. The findings suggest a preventive rather than remedial effect of workplace social support in reducing occupational stress and burnout.

Adult↗
PubMed1985

The riboflavin-sensitized photooxidation of horseradish apoperoxidase.

Native horseradish peroxidase, as well as its reduced and carboxymethylated form, and the apoenzyme, showed resistance to photodynamic action. Sensitivity to this action was detected only in reduced and carboxymethylated apoenzyme, when the photooxidation of its histidine residues was observed. When analyzing the bulk hydrophobic character (Hf) and the accessibility coefficients (Br) in those amino acid residues which can be subjected to photooxidation in horseradish peroxidase, it was found that all of them are situated in hydrophobic zones with low accessibility coefficients. This could justify the high resistance of this enzyme to photodynamic action. The only exception is tryptophan-117, which has low values of Hf and Br, and therefore its resistance to photodynamic action can only be explained in terms of its location and environment. Tryptophan-117 would be situated in a zone of antiparallel beta-structure, according to Chou and Fasman's predictive method for protein conformation.

Apoenzymes↗
PubMed1984

Toward a multi-method approach to assessing the effects of social support.

Two studies were done to assess the direct and stress-buffering effects of social support on psychological symptoms of college students. Three conceptually distinct measures were used to assess different aspects of social support: receipt of supportive transactions, satisfaction with support received, and social support network characteristics. The results indicated a significant direct and stress-buffering effect for support satisfaction in reducing psychological symptomatology. Two measures of support network size were used: number of people who were both a source of supportive and of upsetting interactions (conflicted support network), and number of people who were only mentioned as a source of support (unconflicted support network). Conflicted network size was positively related to symptomatology and increased the relationship between stress and symptomatology. No direct or interaction effects were obtained for unconflicted network size in predicting symptomatology.

Adaptation, Psychological↗
PubMed1984

Hemodynamic consequences of halothane anesthesia during chronic anemia.

The hemodynamic effects of halothane anesthesia in chronically anemic mongrel dogs were evaluated. Control and anemic animals (13.7 +/- 0.4 g/dl hemoglobin mean +/- SE vs. 3.4 +/- 0.3 g/dl) were exposed to 0.75, 1.5, and 2.25% inspired halothane and changes in cardiac output (CO), heart rate (HR), dp/dt, heart work, heart efficiency, myocardial oxygen consumption (MVO2), mean arterial blood pressure (MABP), central venous pressure (CVP), left ventricular end-diastolic pressure (LVDP), left coronary blood flow (CBF), systemic vascular resistance (SVR), and myocardial lactate metabolism were measured and compared. Anemic dogs showed a significantly lower SVR at each halothane dose when compared with controls. In addition, SVR progressively decreased with increasing halothane in anemic dogs, while SVR remained unchanged in controls. CO, CBF, MVO2, and heart work all were significantly greater in anemic canines compared with controls with each halothane concentration. Heart efficiency, dp/dt, HR, and MABP were not significantly different in anemic and control dogs. Neither control nor anemic dogs demonstrated myocardial hypoxia as evidenced by a lack of myocardial lactate production. The results from this study suggest that anemic animals appear to tolerate large concentrations of halothane.

Anemia↗
PubMed1983

The structure of social support: a conceptual and empirical analysis.

The growth of research on social support has led to a comparable proliferation in the ways it is conceptualized and operationalized. The overall purpose of the present paper was to bring some clarity to this concept by critically examining how it has been presented in the literature and by proposing both rationally and empirically derived typologies for organizing social support functions. From a review of prominent discussions of support functions, a rational typology was proposed that included six categories: Material Aid, Behavioral Assistance, Intimate Interaction, Feedback, and Positive Social Interaction. To empirically examine the structure of social support, a factor analysis was conducted on items from a scale of socially supportive behaviors. The four factors that subsequently emerged were labeled Directive Guidance, Non-directive Support, Positive Social Interaction, and Tangible Assistance. Application of these findings to the assessment of support and future research on support/well-being relationships were discussed.

Analysis of Variance↗
PubMed1981

Infants' perception of natural and distorted arrangements of a schematic face.

The techniques of visual preference and of habituation were used to test the ability of 1- and 2-month-olds to discriminate various arrangements of the features of the human face. We showed infants schematic drawings of a human face with the features (1) arranged naturally, (2) arranged symmetrically but scrambled, and (3) arranged asymmetrically and scrambled. 2-month-olds discriminated among all 3 arrangements; 1-month-olds appeared not to discriminate between any of them 2-month-olds also showed a preference for a natural arrangement of the features, but 1-month-olds did not. Thus, by 2 months infants may recognize how the features of a natural human face are arranged and generalize that knowledge to schematic faces.

Discrimination Learning↗
PubMed1978

Mexican-American mental health service utilization: a critical examination of some proposed variables.

A number of reports indicate that Mexican-Americans have a lower prevalence of mental health service usage than other ethnic groups. Although a number of factors have been proposed to account for their underutilization, none of the factors have been adequately supported by existing research. Variables associated with the responsiveness and quality of mental health services, particularly the availability of bilingual-bicultural staff, are advocated as the most relevant areas for future research.

Attitude↗