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Biomedical subjects

G Andersson

Publications and source records attributed to G Andersson.

At least 73 records · Page 4Linked to original sources
PubMed1999

Anxiety, optimism and symptom reporting following surgery for acoustic neuroma.

In this study, a sample of 141 patients operated on for acoustic neuroma tumor were followed-up. The patients completed questionnaires on residual symptoms, hearing problems, anxiety, and optimism. Postoperative facial function was assessed by the treating physician. Multiple regression analyses showed that anxiety, age, and facial function were associated with symptom reporting. Anxiety was also related to hearing problems. Optimism was not associated with either symptoms or hearing problems. Results on the Beck Anxiety Inventory showed that relatively few patients had a moderate degree of anxiety.

Adaptation, Psychological↗
PubMed1999

Altered adaptive behaviour expressed in an open-field paradigm in experimental hepatic encephalopathy.

Chronic hepatic encephalopathy (HE) encounters a neuropsychiatric syndrome arising as a complication to liver dysfunction. Patients with chronic HE display a great variety of neuropsychiatric symptoms including such mental derangements as adaptational difficulty, and deteriorated learning and memory capacity. The portacaval shunt (PCS) in the rat is a widely used model for experimental chronic HE. In the present study, the adaptive capacity of unhabituated PCS rats and sham-operated control rats were studied by measuring two exploratory behaviours (locomotion and rearing) during 5 or 60 min, at four consecutive days or nights with 24 h between sessions. The results revealed that PCS and sham-operated control rats showed parallel behavioural outcome over the four sessions in the 5-min trial. However, at the four consecutive test sessions in the 60-min trials, the sham-controls displayed a continuing decrease in overall activity between sessions whereas the PCS rats evidenced a repeated and stable activity level. These results indicate a presence of a long-term habituation deficiency as exhibited by the PCS rats. Additionally, the results indicate that differences in normal open-field motor behaviour between PCS rats and controls may not be found if such tests are conducted repeatedly during night-time but may emerge when tested repeatedly during daytime. The results may also be interpreted as a possible impaired learning/memory capacity in PCS rats. However, further investigations of how the PCS procedure affects entities of adaptation and learning ability are needed before any conclusions may be drawn since this is the first report of such an impairment in experimental chronic HE when represented by the PCS rat.

Adaptation, Psychological↗
PubMed1999

Spatial facilitation of motor evoked responses in monitoring during spinal surgery.

During spinal cord monitoring, motor responses in the tibialis anterior muscles were recorded on transcranial electrical stimulation of the motor cortex. In order to facilitate the responses, the cortical stimulus was preceded by a train of stimuli to the foot sole within the receptive field of the withdrawal reflex of the tibialis anterior muscle. This cutaneous input provides a spatial facilitation of the cortically elicited response. When the stimulus interval was 50-100 ms, large and reliable responses were seen in most cases.

Adolescent↗
PubMed1999

Distinguishing levels of tinnitus distress.

Degrees of tinnitus distress were explored in a sample of 216 patients who completed audiological measures and were assessed in a structured interview conducted by a clinical psychologist. The Klockhoff and Lindblom grading system was used and its inter-rater reliability assessed in a subsample showing a high degree of correspondence. Results from the interview are reported in terms of variability of tinnitus, characteristics of problematic situations, distress caused by tinnitus, possibilities to cope, and other influencing factors. Finally, a set of discriminant analyses were conducted on the data set resulting in a final model which included pitch, minimal masking level (MML), tolerance in relation to onset, and avoidance of situations because of tinnitus. This model correctly classified 73% of the subjects into the two levels of distress (grade II and III). There may be a potential role for MML as an outcome variable in tinnitus treatment research.

Adaptation, Psychological↗
PubMed1999

Speech-reading: cognitive predictors and displayed emotion.

The present study had three aims: to examine the effects of displayed emotion and message length on speech-reading performance, and how measures of working memory (cf. Baddeley 1986) and verbal information processing speed relate to speech-reading performance. Words and sentences with either positive or negative meaning were used in a word decoding and a sentence-based speech-reading test. A total of 48 normal-hearing subjects participated. The results revealed general effects of displayed emotion, message meaning and message length and no effect of displayed emotion vs message length. Furthermore, working memory but not verbal information processing speed nor accuracy predicted speech-reading performance. The results were discussed with respect to a model of face-processing (Bruce & Young 1986) and with respect to clinical implications.

Adult↗
PubMed1999

Increased cortical bone mineral content but unchanged trabecular bone mineral density in female ERbeta(-/-) mice.

Ovariectomy in young, growing rodents results in decreased trabecular bone mineral density (BMD) and increased radial growth of the cortical bone. Both of these effects are reversed by treatment with estrogen. The aim of the present study was to determine the physiological role of estrogen receptor-beta (ERbeta) on bone structure and bone mineral content (BMC). The BMC was increased in adult (11 weeks old), but not prepubertal (4 weeks old), female ERbeta(-/-) mice compared with wild-type (WT) mice. This increase in BMC in females was not due to increased trabecular BMD, but to an increased cross-sectional cortical bone area associated with a radial bone growth. Male ERbeta(-/-) mice displayed no bone abnormalities compared with WT mice. Ovariectomy decreased the trabecular BMD to the same extent in adult female ERbeta(-/-) mice as in WT mice. The expression levels of osteoblast-associated genes - alpha1(I) collagen, alkaline phosphatase, and osteocalcin mRNAs - were elevated in bone from adult ERbeta(-/-) females compared with WT mice. These observations provide a possible explanation for the increased radial bone growth seen in female mutants, suggesting a repressive function for ERbeta in the regulation of bone growth during female adolescence. In summary, ERbeta is essential for the pubertal feminization of the cortical bone in female mice but is not required for the protective effect of estrogens on trabecular BMD.

Aging↗
PubMed1999

Tartrate-resistant bone acid phosphatase: large-scale production and purification of the recombinant enzyme, characterization, and crystallization.

Tartrate-resistant acid phosphatase (TRAP) is an enzyme expressed in bone-resorbing osteoclasts and certain tissue macrophages in human tissues. The functions of TRAP in biological systems are not known. Elucidation of the three-dimensional structure of the active site could yield important information about the physiological substrate(s) of the enzyme. We have produced recombinant rat bone TRAP using a baculovirus expression vector system. The production was scaled up to a 30-l bioreactor, and a method of purification in large scale was developed. The enzyme is composed of one 34 kDa polypeptide chain. Trypsin digestion resulted in a preparation where two subunits of approximately 23 kDa and approximately 16 kDa appeared after disulfide reduction. Trypsin digestion activated the enzyme. We generated monoclonal antibodies against recombinant TRAP. One of the selected antibodies detected the 23 kDa subunit in Western blotting. The reduced and oxidized forms of the enzyme could be separated by Mono-S cation-exchange chromatography. Crystals of TRAP have been obtained with ammonium sulfate/polyethylene glycol as precipitant. They belong to space group P212121 or P21212 with unit cell dimensions a = 57.2 A, b = 69.5 A, and c = 87.2 A and diffract to at least 2.2 A resolution. A packing density value of 2.55 A3/Da is consistent with one subunit in the asymmetric unit.

Acid Phosphatase↗
PubMed1999

A meta-analytic review of psychological treatments for tinnitus.

Meta-analysis is a technique of combining results from different trials in order to obtain estimates of effects across studies. Meta-analysis has, as yet, rarely been used in audiological research. The aim of this paper was to conduct a meta-analysis on psychological treatment of tinnitus. The outcomes of 18 studies, including a total of 24 samples and up to 700 subjects, were included and coded. Included were studies on cognitive/cognitive-behavioural treatment, relaxation, hypnosis, biofeedback, educational sessions and problem-solving. Effect sizes for perceived tinnitus loudness, annoyance, negative affect (e.g. depression) and sleep problems were calculated for randomized controlled studies, pre-post-treatment design studies and follow-up results. Results showed strong to moderate effects on tinnitus annoyance for controlled studies (d = 0.86), pre-post designs (d = 0.5) and at follow-up (d = 0.48). Results on tinnitus loudness were weaker and disappeared at follow-up. Lower effect sizes were also obtained for measures of negative affect and sleep problems. Exploratory analyses revealed that cognitive-behavioural treatments were more effective on ratings of annoyance in the controlled studies. It is concluded that psychological treatment for tinnitus is effective, but that aspects such as depression and sleep problems may need to be targeted in future studies.

Adaptation, Psychological↗
PubMed1998

The role of protein kinase C signaling in activated DRA transcription.

Expression of human MHC HLA-DRA class II gene can be up-regulated in B cells by Ig cross-linking as well as by phorbol esters such as 12-O-tetradecanoyl phorbol 13-acetate (TPA). Induced DRA expression involves activation of restricted protein kinase C (PKC) isoforms, resulting in activated activator protein-1-dependent transcription. In this report expression profiles and activation of PKC were analyzed in human Raji B lymphoblastoid cells. Transient transfection analysis with target plasmids containing either DRA promoter (wild-type or mutated) or TPA response elements demonstrated that pretreatment with the selective PKC inhibitor GF 109203X repressed TPA-mediated activation. Western analysis performed on cellular fractions of resting cells and of TPA-activated cells revealed abundant expression of classical PKC-alpha (cPKC-alpha), cPKC-betaII, and atypical PKC-zeta isoforms and identified a sustained translocation of cPKC-alpha and cPKC-betaII from the cytosolic compartment to membranes. As expected, the distribution of atypical PKC-zeta was unaffected by TPA treatment and displayed an even distribution between cytosol and membranes. This finding was confirmed by immunofluorescence microscopy. The TPA-mediated translocation of cPKC-alpha and cPKC-betaII was not influenced by pretreatment with GF 109203X. Finally, functional activation and translocation of PKC were investigated with a selective in vitro kinase assay. Together, these results show that activated HLA-DRA expression in response to TPA treatment is strictly dependent on PKC activation acting on the X2 box of the DRA promoter and that selective inhibition of PKC enzymatic activity does not influence subcellular localization of expressed PKC isoenzymes. Thus, the translocation event per se occurs independently of PKC activation in these cells.

B-Lymphocytes↗
PubMed1998

The insulin-like growth factor (IGF)binding protein 1 binding epitope on IGF-I probed by heteronuclear NMR spectroscopy and mutational analysis.

NMR spectroscopy studies and biosensor interaction analysis of native and site-directed mutants of insulin-like growth factor I (IGF-I) was applied to identify the involvement of individual residues in IGF-I binding to IGF-binding protein 1 (IGFBP-1). Backbone NMR chemical shifts were found to be affected by IGFBP-1 binding in the following residues: Pro2, Glu3, Cys6, Gly7, Gly19, Pro28-Gly30, Gly32, Arg36, Arg37, Gln40-Gly42, Pro63, Lys65, Pro66, and Lys68-Ala70. Three IGF-I arginine side chains were identified by NMR to participate in IGFBP-1 binding. All IGF-I arginine residues were replaced by alanines, using site-directed mutagenesis, in four single substituted variants, IGF-I(R21A), IGF-I(R50A), IGF-I(R55A), and IGF-I(R56A), and one double replacement mutant, IGF-I(R36A/R37A). Biosensor interaction analysis binding studies demonstrate the involvement of Arg36-Arg37 and Arg50 in IGFBP-1 binding, while experiments with the IGF-I receptor implicate Arg21, Arg36-Arg37, and Arg56 as part of the receptor binding epitope. These overlapping binding surfaces explain why IGF-I receptor and IGFBP-1 binding to IGF-I is competitive. The C terminus of free, but not IGFBP-1-bound, IGF-I is found to exist in two distinct, NMR-detectable conformations at 30 degreesC. One possible explanation for this structural heterogeneity could be cis-trans isomerization of the Cys6-Cys48 disulfide bond.

Amino Acid Sequence↗
PubMed1998

Evolution of the human HLA-DR region.

The genomic organization and number of human HLA-DRB class II genes differs between haplotypes in the human population. In contrast, both HLA-DQ and -DP class II subregions are conserved. Understanding of the evolutionary relationship and age of HLA-DR haplotypes has been obtained by nucleotide sequence determination and phylogenetic analyses of intron sequences of all known DRB genes from different DR haplotypes. These analyses have indicated that the gene organization of some haplotypes has remained conserved for tens of millions of years and that novel haplotypes have originated during hominoid speciation. Thus, in the contemporary human population, both ancestral and species-specific DRB gene organizations are found. The plasticity of DR gene organization as well as the extensive allelic polymorphism of expressed DR-beta molecules are features which suggest that DR molecules are under distinct selective pressure compared to HLA-DQ and HLA-DP class II molecules. The extensive allelic polymorphism of HLA-DR transplantation antigens is exclusively provided by the beta-chain of these heterodimeric antigen presenting molecules. Most of this polymorphism appears to have been generated recently. Thus, evolutionary mechanisms involved in the preservation of ancestral gene organizations, selection against DR-alpha polymorphism, creation of DR-beta allelic polymorphism and generation of novel gene organizations are acting on the HLA-DR region simultaneously.

Animals↗
PubMed1998

The immune modulator Linomide prevents neuronal death in injured peripheral nerves of the mouse.

Neuronal death after injury or disease could result from imbalanced cytokine expression. Linomide (LS-2616, quinoline-3-carboxamide), a synthetic immunomodulator with effects on cytokine production, suppresses autoimmune diseases of the nervous system. Here adult mice were pre-treated with 200 mg/kg/day of Linomide for 9 days, after which the sciatic nerves were crushed. After another 10 days of Linomide treatment the dorsal root ganglia were dissected out and stained for apoptosis, either immediately or after 2 days in culture, which increases cell death. Superior cervical ganglia were also cultured for 2 days. The Linomide pretreatment profoundly reduced (approximately 60-80%) the injury-induced apoptotic death of neurons and satellite cells in both systems. The results suggest that modulation of the inflammatory cytokine cascade is a promising road to nerve cell rescue.

Adjuvants, Immunologic↗
PubMed1998

Chondroclasts and osteoclasts in bones of young rats: comparison of ultrastructural and functional features.

The aim of the present study was to characterize cells involved in resorption during endochondral bone formation. We investigated whether the cells involved in cartilage breakdown at the epiphyseal/metaphyseal border, i.e., chondroclasts, share the characteristics of bone/cartilage-resorbing osteoclasts at the metaphyseal/diaphyseal border regarding ultrastructural features and functional activity. Morphometric evaluation showed that chondroclasts do not form ruffled borders and clear zones, i.e., well-known resorption characteristics, to the same extent as osteoclasts, present at the lower metaphysis. Instead, chondroclasts tend to express an undifferentiated surface adjacent to the matrix, not structurally different from the basolateral plasma membrane. Tartrate-resistant acid phosphatase (TRAP) was used as a marker for functional activity. Immunohistochemical staining by light microscopy was strong in both chondroclasts and in osteoclasts. Furthermore, in situ hybridization revealed large amounts of TRAP mRNA in chondroclasts as well as in osteoclasts. Ultrastructural immunohistochemistry suggests extensive secretion of the TRAP enzyme in the ruffled border area of both chondroclasts and osteoclasts. Intracellular accumulation was seen particularly in chondroclasts, possibly as a consequence of a relative disinclination to develop a ruffled border. Thus, semiquantitative estimation of TRAP distribution showed an inverse relationship between extracellular and intracellular TRAP in chondroclasts and osteoclasts. These results indicate that chondroclasts and osteoclasts differ, not only with respect to location but possibly also by mode of action. The observed differences may reflect the maturation sequence of these multinucleated cells when associated with different metaphyseal trabecular surfaces.

Acid Phosphatase↗
PubMed1998

Effects of a cognitive-behavioral pain-management program.

A cognitive behavioral multidisciplinary pain management program was evaluated in two separate outcome studies; one controlled study (study I) and one study conducted on a consecutive sample with a long-term follow-up (study II). The 4-week inpatient treatment program included education sessions, goal setting, graded activity training, pacing, applied relaxation, cognitive techniques, social skills training, drug reduction methods, contingency management of pain behaviors, and planning of work return. The outcome of study I showed significant between-group differences in favor of the treatment group on measures of occupational training at 1-month follow-up, activity level in the sparetime at post-treatment and at follow-up, and decreased catastrophizing and pain behaviors at post-treatment. In study II significant improvements over time were found on measures of sick leave, pain intensity, pain interference, life control, affective distress, activity level in the sparetime, physical fitness and use of analgetics at 2-month follow-up and at 1-year follow-up. The results of the two outcome studies reported show that cognitive behavioral multidisciplinary pain management programs can successfully be applied to Swedish musculoskeletal pain patients.

Adaptation, Psychological↗
PubMed1998

Diurnal and gender effects by chronic portacaval shunting in rats on spontaneous locomotor and rearing activities in an open-field.

Behavioural disturbances in chronic experimental hepatic encephalopathy (HE) have been investigated for several decades, but only in recent years, the possibility for gender-dependent reduction of spontaneous locomotor activity has come under attention. Unfortunately though, the results of such gender dependency have been discrepant. We therefore performed an open-field behavior study in unhabituated female and male portacaval shunted (PCS) rats during both day- and night-time, monitoring locomotor as well as rearing activity for a 60 min period. The results revealed lower locomotor and rearing activities in both male and female PCS rats during night-time, compared to sham-operated controls. Daytime differences could only be detected in the rearing activity of female PCS versus control rats. Female PCS rats also spent less cumulated time rearing, compared to controls but no differences regarding the overall locomotor/rearing activity ratio or portion of the behaviours exerted in the central area of the open-field could be detected between PCS and controls, or between the sexes. Diurnal activity differences were found between control groups of both sexes but not between the female versus male PCS rats. Thus, our results are not supportive of any major gender-dependent behavioural disturbance between PCS and control rats.

Animals↗