Biomedical subjects

E Bergman

Publications and source records attributed to E Bergman.

At least 19 recordsLinked to original sources

PubMed2005

Hypomineralized molars and incisors of unknown origin: treatment outcome at age 18 years.

OBJECTIVE: To assess the outcome of treatment of hypomineralized molars and incisors of unknown aetiology (MIH) in 18-year-olds. DESIGN: A follow-up study including clinical examination, panoramic radiography and intraoral photos. SAMPLE AND METHOD: Seventy-six individuals treated at the Eastman Dental Institute in Stockholm during 1978-2001 with the diagnosis MIH. Severity of enamel defects in molars and incisors, prevalence and distribution of extracted molars, type, quality and median duration of restorations, periradicular condition of affected molars, dental occlusion and space closure in cases of extraction, as well as the individual's satisfaction with the treatment, were assessed. RESULTS: Severe defects with enamel surface breakdown in all four molars occurred in 42% of the individuals and 29% had at least one incisor with yellow/brown opacity in the enamel. At follow up, 42% of the individuals had at least one molar extracted; 18% had all four molars extracted. The median duration of the molar restorations (n = 153) was 5 years. Of the individuals with restored molars, 48% had at least one unacceptable restoration. Periradicular pathology was observed in three molars. The sagittal relations did not differ between individuals with and without extraction of molars. Space closure was acceptable in 87% of the individuals with extracted molars. Eighty percent were satisfied with the treatment. CONCLUSIONS: Extraction of molars with severe enamel defects gave good or acceptable results in a majority of the patients while conservative restorative treatment resulted in a need for additional treatment in approximately half of the patients.

Adolescent↗

PubMed2004

Effect of a graded single constriction of the rat sciatic nerve on pain behavior and expression of immunoreactive NPY and NPY Y1 receptor in DRG neurons and spinal cord.

In the present study, the rat sciatic nerve was constricted to varying degrees using only one ligature with a very thin polyethylene sheath placed between nerve and ligature thread. Complete nerve transection was studied for comparison. With a 40-80% constriction of the nerve we observed allodynia to a similar extent as in the so-called Bennett model based on four loose ligatures. We also monitored changes in the expression of neuropeptide Y (NPY) and the NPY Y1 receptor (Y1R) in the lumbar 4-5 dorsal root ganglia (DRG) and dorsal horn and found upregulation of NPY and downregulation of the Y1R in DRG neurons after injury. These results indicate that similar peptide and receptor changes occur in this model as after axotomy and in other nerve injury models, although the immunohistochemical and behavioral changes seem to be dependent on the degree of constriction of the nerve. Thus, it seems relevant to monitor the degree of constriction when evaluating pain and other post-injury events. The possibility that some of the changes in NPY-ergic neurotransmission are related to the generation of allodynia is discussed; as well as the possibility to use this mononeuropathic model based on a single ligature nerve constriction (SLNC) as a complementary approach to other widely used pain models.

Animals↗

PubMed2002

Dyslexia-specific brain activation profile becomes normal following successful remedial training.

OBJECTIVES: To examine changes in the spatiotemporal brain activation profiles associated with successful completion of an intensive intervention program in individual dyslexic children. METHODS: The authors obtained magnetic source imaging scans during a pseudoword reading task from eight children (7 to 17 years old) before and after 80 hours of intensive remedial instruction. All children were initially diagnosed with dyslexia, marked by severe difficulties in word recognition and phonologic processing. Eight children who never experienced reading problems were also tested on two occasions separated by a 2-month interval. RESULTS: Before intervention, all children with dyslexia showed distinctly aberrant activation profiles featuring little or no activation of the posterior portion of the superior temporal gyrus (STGp), an area normally involved in phonologic processing, and increased activation of the corresponding right hemisphere area. After intervention that produced significant improvement in reading skills, activity in the left STGp increased by several orders of magnitude in every participant. No systematic changes were obtained in the activation profiles of the children without dyslexia as a function of time. CONCLUSIONS: These findings suggest that the deficit in functional brain organization underlying dyslexia can be reversed after sufficiently intense intervention lasting as little as 2 months, and are consistent with current proposals that reading difficulties in many children represent a variation of normal development that can be altered by intensive intervention.

Adolescent↗

PubMed2002

Impairment of peripheral sensory innervation in senescence.

Sensorimotor disturbances are common among elderly and one of the main factors depreciating life quality in senescence. Mechanistically sensory deficits during aging include not only degenerative and regressive events but also phenotypic switches among sensory neurons as well as remodeling of sensory innervation. The pattern of changes suggests that an underlying mechanism is a sustained dependence of sensory neurons on target tissues, and that this dependence, at least in part, appears to be mediated through signaling by target-derived trophic factors. This review presents and discusses evidence supporting this notion.

Aging↗

PubMed2001

Retrograde labeling of primary sensory neurons with fluorescent latex microspheres: a useful tool for long term tagging of neurons.

In this study we have used fluorescent microspheres to retrogradely label primary sensory neurons in dorsal root ganglia (DRGs). Following injection into peripheral nerves, the animals were allowed to survive up to 480 days. Simple profile count indicates that there is a substantial retention of the labeling still after at least 480 days, i.e. about two-thirds of a rat's life span. Moreover, the appearance of the labeling remains quite distinct. Using established markers for axon damage of DRG neurons, we could detect a slight and transient effect of the peripheral nerve injection on the gene expression pattern. It is concluded that fluorescent microspheres represents an attractive means of tagging neurons in experiments covering long time periods.

Animals↗

PubMed2001

Effect of peripheral nerve injury on dorsal root ganglion neurons in the C57 BL/6J mouse: marked changes both in cell numbers and neuropeptide expression.

Several types of changes have been reported to occur in dorsal root ganglia following peripheral nerve injury, including loss of neurons and increases and decreases in peptide expression. However, with regard to loss of neurons, results have not been consistent, presumably due to different quantitative methodologies employed and species analyzed. So far, most studies have been conducted on rats; however, with the fast development of the transgenic techniques, the mouse has become a standard model animal in primary sensory research. Therefore we used stereological methods to determine the number of neurons, as well as the expression of galanin message-associated peptide, a marker for galanin-expressing neurons, neuropeptide Y, and calcitonin gene-related peptide in lumbar 5 dorsal root ganglia of both control C57 BL/6J mice and in mice subjected to a 'mid-thigh' sciatic nerve transection (axotomy). In control animals the total number of lumbar 5 dorsal root ganglion neurons was about 12000. Seven days after axotomy, 24% of the dorsal root ganglion neurons were lost (P<0.001), and 54% were lost 28 days after axotomy (P<0.001). With regard to the percentage of peptide-expressing neurons, the results obtained showed that both galanin message-associated peptide (from <1% to about 21%) and neuropeptide Y (from <1% to about 16%) are upregulated, whereas calcitonin gene-related peptide is downregulated (from about 41% to about 14%) following axotomy. Results obtained with retrograde labeling of the axotomized dorsal root ganglion neurons indicate that the neuropeptide regulations may be even more pronounced, if the analysis is confined to the axotomized dorsal root ganglion neurons rather than including the entire neuron population. We also applied conventional profile-based counting methods to compare with the stereological data and, although the results were comparable considering the trends of changes following axotomy, the actual percentage obtained with the two methods differed markedly, both for neuropeptide Y- and, especially, for galanin message-associated peptide-positive neurons. These present results demonstrate that marked species differences exist with regard to the effect of nerve injury on dorsal root ganglion neurons. Thus, whereas no neuron loss is seen in rat up to 4 weeks after a 'mid-thigh' transection [Tandrup et al. (2000) J. Comp. Neurol. 422, 172-180], the present results indicate a dramatic loss already after 1 week in mouse. It is suggested that the proximity in physical distance of the lesion to the cell body is a critical factor for the survival of the target-deprived neurons. Finally, stereological methodology seems warranted when assessing the total number of neurons as well as changes in peptide regulations after axotomy in mouse.

Animals↗

PubMed2001

You can do it if you set your mind to it: a qualitative study of patients with coronary artery disease.

AIMS OF THE STUDY: To gain increased knowledge and understanding of what it means to be afflicted with coronary artery disease (CAD) and how it affects the life/lifestyle of the individual. BACKGROUND: Research has documented that education, counselling and behavioural interventions are important elements of cardiac rehabilitation and compliance with treatment. Compliance is generally better with medical treatment than with recommended lifestyle changes. Another influencing aspect is locus of control, i.e. people's own understanding of control is the foundation for the decisions patients make more or less consciously regarding compliance with caring/nursing, treatment and lifestyle changes. METHODS: Eight individuals with diagnosed coronary artery disease were interviewed about their life situation, and the opportunities and obstacles they encountered in making lifestyle changes. These interviews were transcribed and then analysed using a hermeneutic approach. FINDINGS: The findings included three areas: (1) The causes of coronary artery disease describing different factors, such as heredity, lifestyle and demands. (2) Difficulties in the work of rehabilitation, which was explained in terms of informants' feelings of confusion, uncertainty and sadness. (3) Successful rehabilitation consisted of two factors: the personality of the individual patient and external support. CONCLUSIONS: Patients may comply well with follow-up visits but less with lifestyle changes. By identifying different 'characteristics', 'prerequisites' and 'difficulties' that describe patients' compliance, it should be possible to make treatment more individual. Nurses have a significant role in supporting these patients since they are more accessible than physicians. Nurses also have a responsibility to work together with patients to empower them, in order to make their lifestyle changes and self-care activities manageable.

Aged↗

PubMed2000

Brain activation profiles in dyslexic children during non-word reading: a magnetic source imaging study.

The purpose of the study was to identify spatiotemporal brain activation profiles associated with phonological decoding in dyslexic children using magnetic source imaging. For this purpose maps of regional cerebral activation were obtained from eleven children diagnosed with dyslexia and ten children without reading problems during engagement in a pseudoword rhyme-matching task. All dyslexic children showed aberrant activation maps consisting of reduced activity in temporoparietal areas in the left hemisphere (including the posterior part of the superior temporal, angular and supramarginal gyri) and increased activity in the right homotopic region. In contrast, the two groups of children did not differ in the degree of activity in basal temporal areas that typically precedes temporoparietal activation. This is the first study to demonstrate the existence of distinct activation profiles associated with phonological decoding in individual dyslexic children.

Adolescent↗

PubMed2000

Regulation of NGF-family ligands and receptors in adulthood and senescence: correlation to degenerative and regenerative changes in cutaneous innervation.

During development, a highly differential neurotrophin dependency is reported for various types of nerve endings in the whisker follicle. To what extent these dependencies extend and play a role in adulthood is largely unresolved. We show here, using in situ hybridization and immunohistochemistry that the expression of neurotrophins and trk/p75 receptors persists in adulthood. As suggested by their expression profiles, many classes of cutaneous nerve endings disclose similar ligand-receptor dependencies in adult animals as during development, while other populations appear to switch their dependency. Furthermore, our data suggest that sensory endings that have a high turnover due to mechanical wear and tear, e. g. Merkel cell-neurite complexes at the level of ring sinus show a more complex ligand-receptor expression phenotype than do endings with a less vulnerable location, e.g. the Merkel cell-neurite complexes at the rete ridge collar. Thus, neurotrophin-3 (NT3)/trkA signalling is suggested to be important for a continuous terminal plasticity of Merkel cell-neurite complexes at the level of ring sinus in adulthood. Evidence supporting a role for neurotrophin signalling in maintaining the adult cutaneous innervation also comes from the close correlation between altered ligand-receptor expression(s) and axonal/terminal aberrations in senescence. Thus, an ageing-related decrease in target neurotrophin expression, notably NT3 and NT4, results in a site-specific loss of sensory terminals concomitant with an aberrant growth of regenerating/sprouting axons into new target fields. Ageing of the cutaneous innervation, manifested in degenerative and regenerative events, seems strongly associated with changes in neurotrophic interactions between sensory neurons and target tissues.

Aging↗

PubMed2000

Cerebral mechanisms involved in word reading in dyslexic children: a magnetic source imaging approach.

The purpose of the present investigation was to describe spatiotemporal brain activation profiles during word reading using magnetic source imaging (MSI). Ten right-handed dyslexic children with severe phonological decoding problems and eight age-matched non-impaired readers were tested in two recognition tasks, one involving spoken and the other printed words. Dyslexic children's activation profiles during the printed word recognition task consistently featured activation of the left basal temporal cortices followed by activation of the right temporoparietal areas (including the angular gyrus). Non-impaired readers showed predominant activation of left basal followed by left temporoparietal activation. In addition, we were able to rule out the hypothesis that hypoactivation of left temporoparietal areas in dyslexics was due to a more general cerebral dysfunction in these areas. Rather, it seems likely that reading difficulties in developmental dyslexia are associated with an aberrant pattern of functional connectivity between brain areas normally involved in reading, namely ventral visual association cortex and temporoparietal areas in the left hemisphere. The interindividual consistency of activation profiles characteristic of children with dyslexia underlines the potential utility of this technique for examining neurophysiological changes in response to specific educational intervention approaches.

Adolescent↗

PubMed2000

Regulation of neurotrophin signaling in aging sensory and motoneurons: dissipation of target support?

A hallmark of senescence is sensorimotor impairment, involving locomotion and postural control as well as fine-tuned movements. Sensory and motoneurons are not lost to any significant degree with advancing age, but do show characteristic changes in gene-expression pattern, morphology, and connectivity. This review covers recent experimental findings corroborating that alterations in trophic signaling may induce several of the phenotypic changes seen in primary sensory and motoneurons during aging. Furthermore, the data suggests that target failure, and/or breakdown of neuron-target interaction, is a critical event in the aging process of sensory and motoneurons.

Aging↗

PubMed2000

A clinical study of root surface conditioning with an EDTA gel. I. Nonsurgical periodontal treatment.

The present study was undertaken to investigate if subgingival administration of an EDTA gel has any adjunctive effect to subgingival and supragingival root debridement. The investigation was performed in one study center involving 6 clinical investigators and 91 patients. The patients were selected from 2 patient populations: 41 were included from a consecutive referral material on a voluntary basis, and 50 were included from a maintenance care material at the clinic. No significant differences were found between the EDTA-treated and control groups with respect to clinical attachment gain or probing pocket depth reduction. The referral patients showed a significant improvement of pocket depth and attachment gain compared to maintenance care patients at the clinic. In multiple regression analyses, it was found that patients with small attachment losses at baseline responded better to treatment than patients with severe periodontitis. Also, in multivariate analyses, referral patients responded better than maintenance patients when controlling for other predictors.

Adult↗

PubMed1999

Reciprocal changes in the expression of neurotrophin mRNAs in target tissues and peripheral nerves of aged rats.

trk receptors are downregulated in both dorsal root ganglion (DRG) and spinal motoneurons of aged rats with behavioral sensorimotor deficits. Here we provide evidence, using reverse transcription-polymerase chain reaction (RT-PCR), of decreased levels of neurotrophin (nerve growth factor, NGF; brain-derived neurotrophic factor, BDNF; neurotrophin-3, NT-3; and neurotrophin-4, NT-4) mRNAs in target muscles. Moreover, the degree of neurotrophin mRNA decrease in target muscles seems to co-vary with the extent of sensorimotor disturbances. In contrast, the peripheral nerve of aged rats showed a reciprocal regulation of neurotrophins, with increased levels of NGF, BDNF, and NT-4 mRNAs. Taken together, evidence suggest an aging-related attenuation of neurotrophin signaling between target tissues, on one hand, and DRG and motoneurons, on the other, and, furthermore, that target-derived neurotrophins regulate the expression levels of trk mRNAs in both DRG and motoneurons.

Animals↗

PubMed1999

Effects of aging and axotomy on the expression of neurotrophin receptors in primary sensory neurons.

Aging is accompanied by declined sensory perception, paralleled by widespread dystrophic and degenerative changes in both central and peripheral sensory pathways. Several lines of evidence indicate that neurotrophic interactions are of importance for a maintained plasticity in the adult and aging nervous system, and that changes in the expression of neurotrophins and/or their receptors may underpin senile neurodegeneration. We have here examined the expression of neurotrophin receptor (p75NTR, trkA, trkB, and trkC) mRNA and protein in intact and axotomized primary sensory neurons of young adult (3 months) and aged (30 months) rats. To examine possible differences among primary sensory neuron populations, we have studied trigeminal ganglia (TG) as well as cervical and lumbar dorsal root ganglia (DRG). In intact aged rats, a decrease in trk (A/B/C) mRNA labeling densities and protein-like immunoreactivities was observed. The decrease was most pronounced in lumbar DRG. In contrast, a small, not statistically significant, increase of p75NTR expression was observed in aged DRG neuron profiles. After axotomy, a down-regulation of mRNA and protein levels was observed for all neurotrophin receptors (p75NTR, trkA, trkB and trkC) in both young adult and aged rats. Consistent with the higher expression levels of neurotrophin receptors in unlesioned young adult primary sensory neurons, the relative effect of axotomy was more pronounced in the young adult than aged rats. Although a decrease in mean cell profile cross-sectional areas was found during aging and after axotomy, the characteristic distribution of neurotrophin receptor expression in different populations of NRG neurons was conserved. The present findings suggest an attenuation of neurotrophic signaling in primary sensory neurons with advancing age and that the expression of p75NTR and trks is regulated differently during aging. A similar dissociation of p75NTR and trk regulation has previously been reported in other neuronal systems during aging, suggesting that there may be a common underlying mechanism. Decreased access to ligands, disturbed axon function and systemic changes in androgen/estrogen levels are discussed as inducing and/or contributing factors.

Aging↗

PubMed1999

Upregulation of GFRalpha-1 and c-ret in primary sensory neurons and spinal motoneurons of aged rats.

Aging is associated with a decline in neuromuscular and somatosensory functions. Senile muscle atrophy, considered to be of neurogenic origin, is prevalent, and sensory thresholds increase with age. However, the loss of motoneurons and primary sensory neurons is small, while sensory and motor innervation appears disturbed due to aging-related axon lesions. One mechanism which may play a role in this process is altered trophin signaling. We here report that the glial cell line-derived neurotrophic factor (GDNF) receptor GFRalpha-1 mRNA and GFRalpha-1 protein-like immunoreactivity are upregulated in spinal motoneurons, and in dorsal root ganglion neurons of 30-month-old rats. The established signaling mechanism for the GDNF/GFRalpha-1 complex is through binding to the tyrosine kinase receptor encoded by the c-ret proto-oncogene, and we also show here that c-ret mRNA is upregulated in both motoneurons and primary sensory neurons of aged rats. The findings reported here, combined with evidence presented in other studies of changes in p75(NTR) and trk receptor expressions in aging primary sensory neurons and motoneurons, point at marked alterations in trophin signaling in senescence.

Aging↗

PubMed1999

Neuropeptides, nitric oxide synthase and GAP-43 in B4-binding and RT97 immunoreactive primary sensory neurons: normal distribution pattern and changes after peripheral nerve transection and aging.

We have here sought to cross-correlate the expression of immunoreactivities for several neuropeptides, nitric oxide synthase (NOS) and the growth associated protein GAP-43 in subpopulations of dorsal root ganglion (DRG) neurons tagged by the selective markers isolectin B4 and the neurofilament antibody RT97, selective for, respectively, subpopulations of small and large DRG neurons. By use of double- and triple-labeling immunohistochemistry, non-manipulated and sciatic nerve transected young adult rats as well as aged (30-months-old) rats were examined using a confocal microscope equipped with enhanced spectral separation. In young adult rats, the DRG neuron profiles could be divided into three subpopulations (B4 binding (B4+) approximately 50%; RT97-immunoreactive (RT97+) approximately 35%; B4-/RT97- approximately 15%). Calcitonin gene-related peptide (CGRP) is expressed in all three subpopulations. Galanin message-associated peptide (GMAP) colocalize with CGRP (100%) but is not expressed in RT97+ profiles. NOS is present in the RT97- subpopulations and frequently colocalize with CGRP (92%). GAP-43 is expressed in all three DRG subpopulations and colocalize with CGRP (88%), GMAP (38%) and/or NOS (22%). Only very small differences were seen among the young adult rats, implicating that the size of respective subpopulation as well as the expression pattern for neuropeptides, NOS and GAP-43 are fairly stable. Sciatic nerve transection reduced B4-binding but not RT97-like immunoreactivity. Distinct changes in the expression of neuropeptides, NOS and GAP-43 were evident in the DRG subpopulations and, furthermore, the regulatory changes were very similar among the lesioned animals. The relative size of the DRG subpopulations was unaffected by aging, while the expression of neuropeptides was altered showing similarities with the changes induced by axotomy in young adult rats.

Aging↗

PubMed1999

Evidence for increased GDNF signaling in aged sensory and motor neurons.

Several lines of evidence suggest that attenuated neurotrophin signaling may account for some of the aging-related phenotypic changes observed in motor and sensory neurons. Glial-derived neurotrophic factor (GDNF) signals through the GFRalpha-1-RET receptor complex and has trophic effects on both primary sensory neurons and, in particular, motoneurons. In this study we provide evidence using RT-PCR that GDNF, but not neurturin, is strongly up-regulated in target muscles (800%) and to a lesser extent also in peripheral supportive tissues. Results here, and in an earlier study, show that the up-regulation of GDNF in target and supportive tissues parallels an increased neuronal expression of the cognate receptors. Increased GDNF signaling may explain some of the phenotypic characteristics of aging sensory and motoneurons.

Aging↗

PubMed1999

Skin-prick test for severe marginal periodontitis.

The present study tested the hypothesis that treatment-resistant periodontitis patients present with a more intense inflammatory response to marginal bacterial plaque as a sign of an inflammatory overreaction. Patients with severe marginal periodontitis (Gingival Index > 20%) who had not responded to treatment showed almost no positive response to lipid A in a skin-prick test, which was significantly different from the results from patients with severe marginal periodontitis who had responded to treatment and from healthy control individuals without marginal periodontitis. This finding can be interpreted as an impaired inflammatory reactivity to periodontitis pathogens in treatment-resistant patients, rejecting the hypothesis.

Adult↗