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Biomedical subjects

N Lindberg

Publications and source records attributed to N Lindberg.

12 recordsLinked to original sources
PubMed2002

Effect of a single-dose of olanzapine on sleep in healthy females and males.

The effect of a single dose of 10 mg olanzapine on healthy volunteers of both sexes was examined using polysomnography and power spectral analysis. The structure and continuity of sleep were unaffected by olanzapine in both sexes. The increase in both actual sleep time and slow wave sleep in females correlated with the increase in theta power, while delta power was not significantly elevated, suggesting that theta power may be a sensitive indicator of changes in sleep. The changes in sleep had the same tendency in men, but they were not significant. The difference between the sexes could not be explained by differences in body mass index. Olanzapine affects sleep probably through 5-HT(2C) receptors. The receptor gene is located on the X-chromosome, inducing an allelic difference between the females and males. This difference may contribute to the different effects of olanzapine on sleep. Olanzapine seems to preserve the normal structure of sleep and increase the amount of slow-wave sleep, which might be of additional benefit in treatment of schizophrenia. The effective clinical dose may be lower for females than males.

Adult↗
PubMed2000

Potential of coded excitation in medical ultrasound imaging.

Improvement in signal-to-noise ratio (SNR) and/or penetration depth can be achieved in medical ultrasound by using long coded waveforms, in a similar manner as in radars or sonars. However, the time-bandwidth product (TB) improvement, and thereby SNR improvement is considerably lower in medical ultrasound, due to the lower available bandwidth. There is still space for about 20 dB improvement in the SNR, which will yield a penetration depth up to 20 cm at 5 MHz [M. O'Donnell, IEEE Trans. Ultrason. Ferroelectr. Freq. Contr., 39(3) (1992) 341]. The limited TB additionally yields unacceptably high range sidelobes. However, the frequency weighting from the ultrasonic transducer's bandwidth, although suboptimal, can be beneficial in sidelobe reduction. The purpose of this study is an experimental evaluation of the above considerations in a coded excitation ultrasound system. A coded excitation system based on a modified commercial scanner is presented. A predistorted FM signal is proposed in order to keep the resulting range sidelobes at acceptably low levels. The effect of the transducer is taken into account in the design of the compression filter. Intensity levels have been considered and simulations on the expected improvement in SNR are also presented. Images of a wire phantom and clinical images have been taken with the coded system. The images show a significant improvement in penetration depth and they preserve both axial resolution and contrast.

Acoustics↗
PubMed2000

Toward an interpersonal life-stress model of depression: the developmental context of stress generation.

The validity of a developmentally based life-stress model of depression was evaluated in 88 clinic-referred youngsters. The model focused on (a) the role of child-environment transactions, (b) the specificity of stress-psychopathology relations, and (c) the consideration of both episodic and chronic stress. Semistructured diagnostic and life-stress interviews were administered to youngsters and their parents. As predicted, in the total sample child depression was associated with interpersonal episodic and chronic stress, whereas externalizing disorder was associated with noninterpersonal episodic and chronic stress. However, the pattern of results differed somewhat in boys and girls. Youngsters with comorbid depression and externalizing disorder tended to experience the highest stress levels. Support was obtained for a stress-generation model of depression, wherein children precipitate stressful events and circumstances. In fact, stress that was in part dependent on children's contribution distinguished best among diagnostic groups, whereas independent stress had little discriminative power. Results suggest that life-stress research may benefit from the application of transactional models of developmental psychopathology, which consider how children participate in the construction of stressful environments.

Adolescent↗
PubMed1999

Depression and Axis II symptomatology in an adolescent community sample: concurrent and longitudinal associations.

The relationship between personality pathology and depression has been the focus of increasing attention, but few investigators have examined this issue prospectively or in adolescent community samples. The present study used both self report and interviewer assessments of personality disorder symptomatology and depression in a sample of 155 late adolescent women followed over three years. Personality pathology cluster and total scores demonstrated moderate to fairly high degrees of stability, indicating endurance of these traits in late adolescence. As predicted, Axis II symptoms were associated with concurrent depressive symptomatology. Overall, self-reported personality disorder symptoms, as well as those specifically in Clusters A and B, predicted interviewer-rated depression over two years beyond the contribution of initial depression, indicating that subclinical Axis II symptoms are a risk factor for subsequent depressive symptomatology.

Adolescent↗
PubMed1997

The relationship between attachment cognitions and psychological adjustment in late adolescent women.

This longitudinal study of 137 female high school seniors investigated the relationship of attachment cognitions, current psychological functioning, and psychological functioning 12 months later. Attachment cognitions, assessed with the Revised Adult Attachment Scale and the Inventory of Parent and Peer Attachment, were significantly associated with current symptomatology. The Revised Adult Attachment Scale, in interaction with initial symptomatology, predicted depression, substance abuse, eating disorders, and personality disorders 12 months later. The Inventory of Parent and Peer Attachment parent subscales predicted eating disorder and personality disorder symptomatology, whereas the peer subscales predicted substance abuse, eating disorder, and personality disorder symptomatology.

Adaptation, Psychological↗
PubMed1997

Predictors of the generation of episodic stress: a longitudinal study of late adolescent women.

The effects of depression and Axis I comorbidity on subsequent self-generated life stress were examined in a longitudinal sample of 134 late adolescent women. The results indicated that specific forms of psychopathology constitute a risk factor for future self-generated episodic stress, even when controlling for prior chronic stress. Comorbid depression had a particularly salient effect in the prediction of stress related to interpersonal conflicts. The effects of family psychopathology and sociotropy were mediated through participant psychiatric status, whereas autonomy made an independent contribution to the prediction of episodic stress. These results support C. Hammen's (1991b) stress generation model in a community sample, demonstrating how individuals with depression play a role in the creation of stress, and also refine prior work by showing that only the comorbid form of depression is associated with subsequent conflict-related stress.

Adolescent↗
PubMed1988

Experiences in the psychotherapy of rheumatoid arthritis.

According to the relevant literature, psychological factors may play an important role in the onset and clinical course of rheumatoid arthritis. This is the first study reported in which the treatment of rheumatoid arthritis is based on such factors. Twenty-seven arthritics were treated psychotherapeutically and a close connection was seen between the course of the psychotherapy and the development of the somatic disease.

Arthritis, Rheumatoid↗
PubMed1985

Uptake and release of gamma-aminobutyric acid in the guinea pig cochlear nucleus after axotomy of cochlear and centrifugal fibers.

This study attempts to determine if gamma-aminobutyric acid (GABA) may be a transmitter of cochlear nerve fibers projecting from the cochlea to the cochlear nucleus, and of centrifugal fibers projecting to the cochlear nucleus via the trapezoid body and the acoustic striae of the medulla. The uptake and the electrically evoked release of exogenous [14C]GABA were measured, in vitro, in the three major subdivisions of the guinea pig cochlear nucleus; the anteroventral, posteroventral, and dorsal cochlear nuclei. These activities were compared using unlesioned animals, animals with bilateral cochlear ablations, and animals whose trapezoid body and acoustic striae were interrupted on the right side of the medulla. Subdivisions from unlesioned animals took up [14C]GABA, achieving concentrations in the tissues that were 11-19 times that in the medium. Electrical stimulation evoked a Ca2+-dependent release of [14C]GABA from each subdivision. Bilateral cochlear ablation, which presumably destroyed the cochlear nerve fibers, had no effect on [14C]GABA uptake and release. Section of the trapezoid body and the acoustic striae on the right side of the medulla typically severed all known connections of the right posteroventral and dorsal cochlear nuclei with the rest of the brain, but left intact many connections involved with the right anteroventral cochlear nucleus. This lesion partially depressed [14C]GABA uptake and release in the right posteroventral and dorsal cochlear nuclei, but not in the right anteroventral cochlear nucleus. These findings suggest that one or more of the centrifugal tracts projecting to the cochlear nucleus may be GABAergic, 88% or more of the cochlear nerve fibers probably are not GABAergic, and some neurons of the cochlear nucleus are probably GABAergic.

Animals↗
PubMed1982

Psychotherapeutic examination of patients with suspected chronic solvent intoxication. An overview.

A group of 13 patients, most of them house or industrial painters with strong evidence of chronic solvent intoxication were given psychotherapy, with a view to ascertaining whether psychological factors may have contributed to the signs and symptoms that had persisted after the acute manifestations had either diminished or ceased altogether. All the patients were found to have experienced severe psychic traumata during their first year of life-the preverbal period. This had resulted in defective development of language, which was reflected in a lack of words for expressing emotions; instead these were expressed nonverbally as somatic symptoms. The results of the study indicate unequivocally that in none of the 13 patients were the symptoms due to the toxic effect of solvents, all of them having a psychological rather than a somatic causation. After an analysis of the symptoms by means of an established psychotherapeutic method they diminished in severity and a number of the patients recovered completely.

Adult↗