Cambios en resonancia magnética funcional en estudiantes de medicina con y sin restricción moderada de sueño / Changes in functional magnetic resonance imaging in medical students with and without moderate sleep deprivation

OBJETIVO: Describir los efectos de la restricción moderada del sueño en las regiones cerebrales involucradas en los procesos de inhibición cognitiva, función motora y fluidez fonológica, utilizando imágenes por resonancia magnética funcional (RMf). Materiales y métodos: Se estableció una condición de sueño habitual y otra de restricción moderada en 12 estudiantes diestros de pre y posgrado de Medicina, de entre 20 y 40 años. En ambos estados se utilizó la prueba psicológica de atención d2 e imágenes de RMf con paradigmas de función motora, fluencia fonológica y atención del tipo inhibición de la función ejecutiva Stroop. La restricción moderada de sueño fue de al menos el 63% con respecto al sueño habitual. Resultados: Se encontraron diferencias significativas en la activación cerebral con RMf para la función motora (p<0,05) entre el ciclo de sueño regular y el de restricción moderada. La actividad cerebral en RMf con los paradigmas de atención Stroop y fluidez fonológica no mostró diferencias significativas, así como tampoco la prueba psicológica de atención d2. Discusión: Se encontró interferencia en las activaciones cerebrales de representación motora con la restricción moderada de sueño, pero no se hallaron diferencias significativas en las activaciones de atención tipo Stroop, ni en la tarea de fluencia fonológica o las pruebas de atención d2. Esto podría deberse a una insuficiente restricción del sueño o a eficientes mecanismos de compensación en los sujetos de este estudio. Conclusión: Existen diferencias en las activaciones cerebrales de representación motora en la restricción moderada del sueño medidas con RMf

OBJECTIVE: To describe the effects of moderate sleep deprivation in brain regions involved in cognitive inhibition processes, motor function, and phonological fluency using functional Magnetic Resonance Imaging (fMRI). Materials and methods: A sample of 12 under-graduate and post-graduate medical students, between 20 and 40 years, were subjected to a follow-up of the number of hours of regular sleep in order compare to a moderate sleep deprivation after a nightshift. The d2 attention test and fMRI studies were used in both groups in order to evaluate motor function, verbal fluency and cognitive inhibition, or Stroop paradigms. The moderate sleep deprivation was at least 63% with respect to the regular sleep pattern during the previous week. Results: Significant differences in brain activity were found in fMRI to measure motor function (P<0.05) comparing regular sleep cycle and moderate sleep deprivation. The brain activity with fMRI Stroop paradigms and phonological fluency showed no significant differences between the two conditions, likewise with the psychological attention test d2. Discussion: The fMRI showed interference on motor representation activations in moderate sleep deprivation. No significant differences in fMRI were found in the processes of cognitive inhibition or Stroop paradigms, in phonological fluency, or in the psychological attention test d2. These could be attributed to inadequate sleep deprivation or efficient compensation mechanisms in the subjects of this study. Conclusión: There is a difference showed in fMRI on motor representation activations in moderate sleep deprivation

Changes in the concentration of trigonelline in a semi-arid leguminous plant (Prosopis laevigata) induced by an arbuscular mycorrhizal fungus during the presymbiotic phase.

An in vitro presymbiotic system between mesquite [Prosopis laevigata(Willd.) M.C. Johnst], a semi-arid leguminous plant, and pregerminated spores of Gigaspora rosea Nicol. & Schenck was established. After characteristic hyphal branching, high performance liquid chromatographic analyses of methanol extracts from P. laevigata roots revealed a concentration change in one ultraviolet-detectable product. This product was identified by nuclear magnetic resonance and mass spectrometry as trigonelline, a pyridine alkaloid. The concentration of trigonelline was constant in the aerial parts of the plant with or without G. rosea, but its concentration in the roots increased 1.8-fold when G. roseawas present. Trigonelline may be a regulatory factor during early signal events in the establishment of the arbuscular mycorrhizal symbiosis in P. laevigata.

Pain locus of control scores in chronic pain patients and medical clinic patients with and without pain.

OBJECTIVE: We investigated the association between treatment setting and pain control attributions as assessed by the Pain Locus of Control Scale (PLOC). DESIGN: Nonrandomized consecutive samples. PATIENTS AND SETTING: The patient groups included an outpatient pain clinic sample of chronic pain patients (n = 48), a group of medical clinic outpatients with chronic pain (n = 28), and a group of medical clinic outpatients without current pain (n = 22). Medical clinic patients without current pain were asked to reply to the PLOC items in terms of their usual response when experiencing pain. RESULTS AND CONCLUSIONS: Results indicated that pain clinic patients were the least likely of the three groups to report predictable control of their pain as reflected by their significantly lower "powerful other" and higher "chance" dimension scores. Medical clinic patients without pain reported greater personal control of pain than the other two groups as evidenced by their higher "internality" dimension score and lower "chance" dimension score. Results indicate that pain control appraisals differ among patients with chronic pain and illness as a function of the treatment setting and suggest that differences in cognitive appraisal can affect treatment efficacy.

Psychometric characteristics of a brief measure of pain-related functional impairment.

This study presents reliability and validity data from two samples (pain clinic vs medical clinic) on a five-item self-report scale, termed the Functional Interference Estimate (FIE), designed to measure functional impairment associated with chronic pain. Results from the pain clinic sample demonstrated that the FIE is internally consistent and has satisfactory levels of test-retest reliability, item-total score correlations, and convergent validity. Results from the medical clinic sample demonstrated that the FIE discriminated between medical clinic patients without pain and both medical clinic patients with pain and pain clinic patients. The data support the use of the FIE as one of several available assessment methods for evaluation of pain-related functional impairment.

The effects of child abuse and race on risk-taking in male adolescents.

This study explores the effects of abuse on the risk-taking behaviors of 2973 black and white adolescent males, 412 of whom were sexually or physically abused. Surveys on mental and physical health, risk-taking behaviors and attitudes, and family living were administered to 9th and 12th graders in an urban midwestern state. The surveys included questions on past history of sexual and physical abuse. More black than white males reported experiencing incest, extrafamilial sexual abuse, and physical abuse. As for outcome risk-taking behaviors, blacks were more likely to use illegal substances, run away, skip school, attempt suicide, force partners into sex, and commit violent acts; however, the racial effects decreased when abuse histories were taken into consideration. Whites were more likely to drink and drive, and to drink before having sex; abuse history did not decrease this racial effect. Abuse but not race was predictive of drinking and of having serious drinking problems. The results point to the importance of pediatricians, psychologists, and other healthcare workers, as well as those in the legal and criminal justice system screening for a history of abuse among adolescents who demonstrate these or other risk-taking behaviors.

Substance abuse among sexually abused adolescents and their families.

The concurrence of substance abuse and history of sexual abuse among adolescents has prompted this study of substance abuse patterns among families of adolescents who report incest or extrafamilial sexual abuse. A total of 3,179 ninth-grade students in a rural midwestern state completed a survey that included questions about individual and family substance abuse. Adolescents who had been sexually abused were more likely to report substance abuse for themselves as well as for members of their immediate families. They were also more likely to report that they used substances because of family problems, school problems, and because they were sad, lonely, or angry. Adolescents reporting a parent with an alcohol or a drug problem were more likely to use cigarettes, marijuana, alcohol, or "speed." Adolescents experiencing extrafamilial abuse reported more alcohol abuse and more alcohol-related problems than those who experienced incest. There were similar reports of parental and familial alcohol and drug problems among these experiencing incest and those experiencing extrafamilial abuse. Those with drug-abusing parents, however, were most likely to report some kind of sexual abuse history.

The effect of drug exposure on thyroid hormone levels of newborns.

This study examines the effect of women's alcohol abuse during pregnancy on the thyroid-stimulating hormone (TSH) and thyroxine (T4) levels of their babies at birth. Forty-seven babies were born to mothers identified as substance abusers. Maternal use of marijuana and/or cocaine did not result in newborns' TSH and T4 hormone levels being significantly different from non-substance-abusing controls' TSH and T4 levels. Alcohol use, however, was significantly linked to lower newborn TSH levels, lower than TSH levels of a control sample of newborns whose mothers used marijuana and/or cocaine, and lower than a control sample of newborns whose mothers abused no substances. This finding suggests further investigation of possible links between thyroid functioning and fetal alcohol syndrome (FAS).

Self-control and ego identity development as predictors of unprotected sex in late adolescent males.

Male college students completed an anonymous self-report questionnaire assessing HIV-related knowledge, attitudes, moral development, personality factors and behaviors. Bivariate analyses were used to identify factors associated with high-risk sexual intercourse. Significant demographic psychosocial and behavioral predictors were entered into a logistic regression analysis to evaluate the independent influence of each predictor on unprotected sexual intercourse. Behavioral factors were the most powerful predictors of unprotected sexual intercourse. Adolescents reporting multiple sex partners, drinking and picking-up sex partners were significantly more likely to engage in sex without condoms. Examining psychosocial factors alone, it was found that adolescents who had low scores for ego-development (goal-directedness) and self-control were significantly more likely to engage in sex without condoms. Identification of two personality constructs as underlying predictors of high-risk behavior, while potentially important for the development of effective HIV prevention programs, needs corroboration to further define the interrelationships between these factors and other psychosocial constructs.

Development of an innovative child and youth mental health training and services delivery project.

In 1989 North Carolina began funding a mental health demonstration training and services project to serve severely emotionally disturbed children and youth in the community. During the first two years of this state-university collaboration, consultation and direct services provided by faculty and student trainees have been linked to preexisting services at a mental health center serving three counties. The project has met initial goals of developing new and expanded services, building relationships with other agencies, and integrating university and mental health center staff. More formal process and outcome evaluations are under way. Areas of probable long-standing concern include the need for more cordial working relationships with other agencies and for more participation of parents in treatment and education programs.

Racial targeting of AIDS programs reconsidered.

Most health professionals understand the importance of targeting behaviors, not groups, for disease prevention. Yet with regard to acquired immune deficiency syndrome (AIDS) education programming, target groups have been defined by salient demographic traits, including race, in part due to incomplete knowledge about risk behaviors in various groups. As a result, community and school-based education programs have suffered some mistrust and resentment. This article reports the findings of original research on attitude and behavioral differences between and within racial groups for a college student sample, in response to AIDS education programming. Differences in baseline attitudes and behaviors showed that AIDS-related risk cannot be primarily associated with minority group status. Implications on refinement of targeting strategies are discussed.

Inconsistencies and misperceptions putting college students at risk of HIV infection.

College students are often viewed as being at high risk for human immunodeficiency virus (HIV) infection, due to their needs to engage in exploratory behavior and their needs for peers' social approval, and their sense of invulnerability. The proportion of adolescents who are sexually active is known to be relatively stable; however, the amount of unsafe sex taking place on the college campus is still in question, as well as the relationship between dating patterns and HIV-risk behavior. In this study college students' self-reports of sexual and dating practices were related to sexual frequency and condom use. The results highlight the amount of unprotected sexual behavior in the college group and the difficulty in assessing adolescents' risk of HIV transmission on the basis of self-reported sexual activity and dating behavior. Key issues to target in educating college students about HIV infection are the roles of planning and spontaneity in dating and the fact that inaccurate self-perceptions of monogamy and abstinence may lead them to assume falsely that they are safe from sexually transmitted diseases.