Biomedical subjects

M Könönen

Publications and source records attributed to M Könönen.

At least 19 recordsLinked to original sources

PubMed2006

Subarachnoid hemorrhage is followed by temporomesial volume loss: MRI volumetric study.

OBJECTIVE: To assess whether subarachnoid hemorrhage (SAH) and its treatment is followed by volume loss in temporomesial structures. METHODS: One hundred fifty-five consecutive patients with aneurysmal SAH were randomly assigned to surgical or endovascular treatment. Volumetric MRI was performed in 77 SAH patients with good or moderate clinical outcome 1 year after hemorrhage. A comprehensive neuropsychological test battery was used to evaluate the cognitive performance of the subjects. Thirty healthy individuals were imaged as MRI controls. RESULTS: The normalized hippocampal (HC) volumes were 24.7/23.7 (right/left), and the amygdaloid (AM) volumes were 21.0/20.5 in the matched control population. In SAH patients, the corresponding volumes were smaller, HC 23.2/21.3 (p = 0.072/0.002) and AM 18.4/18.7 (p = 0.012/0.045). In addition, the AM ipsilateral to the ruptured aneurysm was smaller in patients who had undergone surgical treatment (15.7) vs endovascular treatment (20.3; p < 0.001). Treatment modality did not significantly affect the measured HC volumes. The hippocampal but not amygdaloid volumes correlated with the scores of several neuropsychological tests. CONCLUSION: Subarachnoid hemorrhage and its treatment may be followed by atrophy in temporomesial structures. A clear correlation was demonstrated between neuropsychological performance and reduced temporomesial volumes.

Atrophy↗

PubMed2005

Hippocampal damage in newly diagnosed focal epilepsy: a prospective MRI study.

OBJECTIVE: To examine the longitudinal appearance of hippocampal (HC) damage in a prospective follow-up study of patients with newly diagnosed epilepsy. METHODS: A total of 103 patients with newly diagnosed focal epilepsy were scanned with MRI before antiepileptic medication was started. Serial MRI studies were scheduled after 1, 2 to 3, and 5 years of treatment in the ongoing follow-up study. Volumes of the HC were measured from MRI scans according to the Cavalieri method of modern design stereology and compared at different time points together with clinical variables. RESULTS: No difference was observed in the mean HC volumes between controls and patients at baseline, after 1, 2 to 3, and 5 years of follow-up. Individual analysis showed that 8% of patients had HC damage at the time of the diagnosis and 13% of patients developed HC volume decrease during 2 to 3 years of follow-up. These patients had longer duration of seizure disorder and larger seizure number before the epilepsy was diagnosed and treatment started compared with patients who did not show HC damage. CONCLUSIONS: Hippocampal volume decreases occur in individual patients with newly diagnosed focal epilepsy during the first years of treatment. The data obtained suggest that hippocampal volumetry provides a surrogate marker of the epileptic process.

Adolescent↗

PubMed2005

Temporomandibular disorder subtypes according to self-reported physical and psychosocial variables in female patients: a re-evaluation.

Several studies support the relevance of psychological and psychosocial factors in the assessment and management of chronic musculoskeletal pain disorders, including temporomandibular pain disorders (TMDs). The aim of this study was to re-evaluate subtyping approach used in an earlier study (TI Suvinen, KR Hanes, JA Gerschman, PC Reade. J Orofac Pain 1997;11:200) and to compare perceived physical symptoms, psychological, coping and psychosocial variables between subtypes of patients who seek treatment for their temporomandibular pain and dysfunction. A total of 41 consecutive female patients were assessed multiaxially for physical symptoms, coping style and effectiveness and illness behaviour by a previously validated Temporomandibular Pain Dysfunction Questionnaire (TI Suvinen, KR Hanes, JA Gerschman, PC Reade. J Orofac Pain 1997;11:200). Additional measures of psychosocial variables included the global scores of the Beck Depression and Anxiety Inventory and Part I of the Multidimensional Pain Inventory. Subtypes were generated using an iterative partitioning method, k-means cluster analysis. Three clusters were identified and termed as Simple (22%), Intermediate (41%) and Complex (37%) temporomandibular disorders subtypes. Significant differences (P < 0.05) were found between clusters in psychological (coping style and effectiveness, disease conviction and affective disturbance) and in psychosocial variables (daily interference and social, work and family satisfaction), but not between physical variables. The results support previous studies that have shown differences in psychosocial variables in the presentation and subtyping of TMDs and the biopsychosocial orientation in assessment. The findings need to be reverified in a larger sample along specific physical diagnoses, but it is tentatively proposed how the three subtypes could be used in the classification of temporomandibular pain patients to guide management, based on the constellation of predominant psychological and psychosocial illness impact variables.

Adaptation, Psychological↗

PubMed2005

A voxel based morphometry study on mild cognitive impairment.

BACKGROUND: Mild cognitive impairment (MCI) is the most widely used concept in classifying cognitive impairment in the elderly who do not fulfil the criteria for dementia. MCI is considered to confer an increased risk of progressing to dementia and most often Alzheimer's disease (AD). Various approaches such as imaging of the brain have been applied to predict the conversion of MCI to dementia. A number of volumetric magnetic resonance imaging (MRI) studies have detected atrophy of the medial temporal lobe in subjects with MCI, but for the other cerebral regions the results have been inconsistent. OBJECTIVE: To study the pattern of brain atrophy in MCI. METHODS: Thirty two controls and 51 individuals with MCI deriving from population based cohorts were studied by MRI using voxel based morphometry. The threshold of t maps was set at p < 0.001. RESULTS: Individuals with MCI had significant unilateral atrophy in the medial temporal lobe on the right side. Less extensive atrophy was found elsewhere-for example, in the temporal lobe, left superior parietal lobule, left anterior cingulate gyrus, and bilaterally in the thalami. CONCLUSIONS: The MRI findings in MCI resemble those seen in early AD.

Aged↗

PubMed2004

Perceived stress, pain and work performance among non-patient working personnel with clinical signs of temporomandibular or neck pain.

The aim of the present study was to assess the associations between different types of perceived stress, pain and work performance among non-patients with clinical signs of muscle pain in the head/neck region. One-fifth (n = 241) of the 1339 media employees who had participated in a previous survey (Ahlberg J. et al., J Psychosom Res 2002; 53: 1077-1081) were randomly selected for standardized clinical examinations. Altogether 49% (n = 118) of these subjects had clinical signs of temporomandibular and/or neck muscle pain and were enrolled in the present study. The mean age of the study sample was 46.9 years (s.d. 6.6) and the female to male distribution 2:1. Of the 118 employees 46.5% reported that the pain problem interfered with their ability to work. Perceived ability to work was not significantly associated with age, gender or work positions. According to logistic regression, reduced work performance was significantly positively associated with continuous pain [odds ratio (OR) 4.38; 95% CI 1.21-15.7], level of perceived pain severity (OR 1.30; 95% CI 1.04-1.63), and health stress (OR 2.08; 95% CI 1.22-3.54). The results of this study indicated an association between specific self-reported stress regarding health and work issues, pain and work performance. From a preventive perspective this indicates a need for increased awareness about these associations on not only individual level but also at the organizational level and in health care.

Adult↗

PubMed2004

Reported bruxism and biopsychosocial symptoms: a longitudinal study.

OBJECTIVES AND METHODS: In this follow-up study of 30-50-year-old employees (n = 211) of the Finnish Broadcasting Company (YLE), respondents completed questionnaires in both 1999 and 2000 containing items on demographic data, tobacco use, levels of perceived bruxism, affective disturbance, sleep disturbance, somatic symptoms, pain symptoms and temporomandibular disorder (TMD) symptoms. RESULTS: Bruxism was significantly more prevalent among smokers (P = 0.005). Age, marital status, and gender were not associated with bruxism. Subjects in the frequent bruxism group (n = 74) reported the TMD-related painless symptoms, affective disturbance and early insomnia significantly more often than average. In the multivariate analyses, clustered pain symptoms (P = 0.001), TMD-related painless symptoms (P = 0.004) and smoking (P = 0.012) were significantly positively associated with frequent bruxism, when the independent effects of age and gender were controlled for. CONCLUSIONS: It was concluded that successful management of TMD necessitates smoking cessation, as tobacco use may both amplify the patient's pain response and provoke bruxism. Psychosocial factors and perceived stress should not be ignored, however.

Adult↗

PubMed2003

Decreased brain creatine levels in elderly apolipoprotein E epsilon 4 carriers.

Apolipoprotein E (ApoE) genotype has been shown to influence results in neuroimaging studies using a number of various imaging modalities. No in vivo data exists on whether or not there are ApoE-related changes observable by proton magnetic resonance spectroscopy (MRS). In this study we measured absolute peak areas of proton MR spectra obtained from the occipital cortex in 22 non-demented elderly with (n = 8) or without (n = 14) the ApoE epsilon4 allele. No statistically significant differences were found in levels of N-acetyl aspartate, myo-inositol, or choline containing compounds between the groups. Instead, compared with the non-carriers, the levels of creatine were significantly lower in the epsilon4 carriers, suggesting increased metabolic demands in the brain of the epsilon4 carriers. The levels of creatine also correlated significantly with age and performance on the Mini-Mental State Examination test in the epsilon4 carriers, but not in the non-carriers. These findings may be of significant clinical interest as potential indicator of incipient AD, and also from therapeutical point of view given the potential neuroprotective effects of creatine.

Aged↗

PubMed2003

Vertical jaw separation and masseter muscle electromyographic activity: a comparative study between asymptomatic controls & patients with temporomandibular pain & dysfunction.

The aims of the present study were to assess the relationship pattern between bilateral masseter muscle electromyographic (MEMG) activity recordings and vertical jaw separation (VJS). Asymptomatic subjects (n = 15) were compared with age and gender-matched patients (n = 18) with temporomandibular pain and dysfunction (TMPD); before and after undergoing interocclusal appliance (IOA) therapy for 4 months. In asymptomatic subjects a bilateral minimum MEMG activity was found in a 'resting zone' at approximately a quarter of maximum mandibular opening (mean, 15.4 mm of VJS; range, 5.5-22.5 mm including overbite). No overall relationship between MEMG and VJS was shown for patients with TMPD. After successful IOA therapy, the majority of TMPD patients (14 of 18) showed normalization of the relationship between MEMG and VJS, but electromyographic assessment was not found to be of value as a single objective assessment parameter in evaluating the resolution of TMPD or the effectiveness of IOA therapy.

Adolescent↗

PubMed2003

Heterogeneity of cerebral blood flow in symptomatic patients undergoing carotid endarterectomy.

There is still controversy concerning which patients with asymptomatic carotid stenosis or symptomatic moderate stenosis are likely to benefit from carotid endarterectomy. The surgical candidates for carotid endarterectomy should have a high risk for stroke, but a low risk for operative complications. Therefore, new effective patient selection strategies, including haemodynamic testing, schemes of risk stratification and pre-operative cardiac testing, are under investigation. To improve haemodynamic assessment of patients with carotid artery stenosis, we evaluated a novel global cerebral blood flow (CBF) heterogeneity index at rest and after acetazolamide injection in patients undergoing carotid endarterectomy. CBF heterogeneity index was measured in 15 patients by using basal and acetazolamide enhanced 99mTc-HMPAO SPET both before and 1 month after surgery. CBF heterogeneity index was calculated as the coefficient of variation of a total of 44 cerebral regions representing mainly both ipsi- and contralateral grey matter. A high linear correlation was observed between CBF heterogeneity index and ipsilateral carotid stenosis degree (r=0.74, P=0.003). Before surgery, CBF heterogeneity index increased significantly after acetazolamide injection when compared to the basal condition (from 7.0+/-1.5 to 8.3+/-1.7%, P=0.008). This response disappeared after carotid endarterectomy. When compared to pure asymmetry of CBF (ipsi/contralateral CBF ratio), the CBF heterogeneity index seemed to reflect, more sensitively, the haemodynamic effects of carotid endarterectomy. The CBF heterogeneity index after acetazolamide injection is a sensitive marker of the haemodynamic consequences of carotid artery stenosis and its operative treatment.

Acetazolamide↗

PubMed2002

Distinct biopsychosocial profiles emerge among nonpatients.

OBJECTIVES: The cross-sectional study comprised 30- to 55-year-old permanent employees (N=1784) of the Finnish Broadcasting Company (YLE). METHODS: The participants (N=1339, response rate 75%) completed standardised questionnaires covering demographic items, physical health, work performance, stress symptoms, pain and musculoskeletal symptoms, and overall biopsychosocial health. RESULTS: Physical symptoms (present often or continually) were reported by 15%, psychosomatic by 19% and psychosocial by 14%. The intercorrelations between 73 biopsychosocial variables revealed nine factors explaining 54.5% of variance for intrapersonal profiles and four factors explaining 59.2% of variance for interpersonal profiles. The Cronbach alphas for reliability ranged from.76 to.83. Three distinct biopsychosocial cluster profiles were found: Cluster 1 (n=290, 27%) loaded positively with the somatic and psychosocial variables, Cluster 2 (n=558, 51%) loaded negatively with the various biopsychosocial symptoms, and Cluster 3 (n=235, 22%) loaded positively with anxiety. CONCLUSION: Discriminant function analysis confirmed that this cluster solution correctly classified 95.2% of the subjects in a nonpatient multiprofessional population, which supports the biopsychosocial approach also in work life issues.

Adult↗

PubMed2002

Reported bruxism and stress experience.

The aim of the study was to analyze whether perceived bruxism was associated with stress experience, age, gender, work role, and occupational health care use among a nonpatient multiprofessional population. Altogether, 1784 (age 30-55 years) employees of the Finnish Broadcasting Company were mailed a self-administered questionnaire covering demographics, perceived bruxism, total stress experience and the use of health care services provided by the company. The response rate was 75% (n = 1339, 51% men) and mean age was 46 years (SD = 6) in both genders. There were no significant differences in demographic status by age and gender. Bruxism and stress experiences did not significantly vary with regard to category of work, but both were significantly more frequent among women (P < 0.05). In all work categories frequent bruxers reported more stress, and the perceptions were significantly differently polarized between the groups (P < 0.001). According to logistic regression, frequent bruxism was significantly positively associated with severe stress experience (Odds ratio = 5.00; 95% CI = 2.84-8.82) and female gender (Odds ratio = 2.26; 95% CI = 1.43-3.55). Frequent bruxism was also significantly positively associated with the numbers of occupational health care and dental visits (P < 0.01), and slightly negatively associated with increasing age and work in administration (P < 0.05). It was concluded that bruxism may reveal ongoing stress in normal work life.

Administrative Personnel↗

PubMed2001

SPECT and neuropsychological performance in severe depression treated with ECT.

BACKGROUND: In severe depression, studies of regional cerebral blood flow (rCBF) by SPECT have not produced uniform results. The association between changes in SPECT and electroconvulsive therapy (ECT) has shown somewhat conflicting data. No data are available on benzodiazepine receptor function SPECT studies in ECT. METHODS: Twenty drug-resistant adult inpatients fulfilling the DSM-IIIR criteria for major depression were studied by SPECT (rCBF by relative ECD uptake in all, and benzodiazepine receptor function by iomazenil uptake in five subjects) before and 1 week after clinically successful bitemporal ECT. Clinical and neuropsychological test scores were used as references for the possible changes in SPECT. RESULTS: An increased perfusion after ECT was observed in right temporal and bilateral parietal cortices, whereas no reductions in relative ECD uptake were seen after ECT. Iomazenil-SPECT revealed a highly significant increase in the benzodiazepine receptor uptake in all studied cortical regions except temporal cortices. CONCLUSIONS: Clinically successful ECT was associated with changes in vascular perfusion and GABAergic neurotransmission, providing new evidence for the mechanism of action of ECT and for the neurobiology of severe drug-resistant depression.

Adult↗

PubMed2001

Diffusion and perfusion MR imaging in acute ischemic stroke: a comparison to SPECT.

Diffusion (DWI) and perfusion (PWI) magnetic resonance imaging are relatively new methods of clinical imaging that probably can detect infarcted (DWI) and hypoperfused but still salvageable tissue (PWI) in acute human stroke. Forty-six acute stroke patients were imaged within 24 h of ictus, on the second day and after a week. SPECT was also performed on 23 patients in the acute phase (first or second day). On the first day, mean volume of hypoperfused tissue was significantly greater (P<0.001) than the infarcted tissue. The initial hypoperfusion volume correlated significantly with the final infarct size (P<0.001). The initial perfusion-diffusion mismatch correlated significantly with the infarct growth (P< or =0.001). The hypoperfusion volumes measured from PWI and SPECT correlated significantly (P<0.001). In conclusion, combined DWI and PWI is a powerful tool in evaluating the hemodynamics of acute ischemic stroke and can predict the infarct growth during 1 week.

Aged↗

PubMed2001

Phenotypic identification of Actinomyces and related species isolated from human sources.

Recent advancements in chemotaxonomic and molecular biology-based identification methods have clarified the taxonomy of the genus Actinomyces and have led to the recognition of several new Actinomyces and related species. Actinomyces-like gram-positive rods have increasingly been isolated from various clinical specimens. Thus, an easily accessible scheme for reliable differentiation at the species level is needed in clinical and oral microbiology laboratories, where bacterial identification is mainly based on conventional biochemical methods. In the present study we designed a two-step protocol that consists of a flowchart that describes rapid, cost-efficient tests for preliminary identification of Actinomyces and closely related species and an updated more comprehensive scheme that also uses fermentation reactions for accurate differentiation of Actinomyces and closely related species.

Actinomyces↗

PubMed2001

Fusing of dental ceramics to titanium.

Titanium is known as a useful biometal because of its good biocompatibility and mechanical performance. However, titanium is chemically an exceptional metal, reacting strongly with gaseous elements like oxygen, hydrogen, and nitrogen and also dissolving them extensively. This high reactivity causes problems, for example, when dental ceramics are fused to titanium. Commercial ceramic-titanium systems are increasingly used in prosthetic dentistry, but little is known about the microstructure and composition of the system. Better understanding of chemical reactions between ceramics and titanium is necessary if mechanically more compatible ceramic-titanium bonds are to be developed. This review deals with titanium as a metal, titanium's affinity for nonmetallic elements (especially oxygen), and reactions with other elements. Different aspects are discussed relative to the fusing of dental ceramics to titanium.

Biocompatible Materials↗

PubMed2000

Hippocampus and entorhinal cortex in frontotemporal dementia and Alzheimer's disease: a morphometric MRI study.

BACKGROUND: Magnetic resonance imaging (MRI) of hippocampal atrophy is a sensitive but not specific method to support the clinical diagnosis of early Alzheimer's disease (AD). We recently described our findings that atrophy of the entorhinal cortex (ERC) in frontotemporal dementia (FTD) is equal to that found in AD but that hippocampal atrophy in FTD is less than that found in AD. The MRI volumes of these structures provide a topographic representation of the region of interest. We hypothesized that two different dementias with distinct histopathologic and clinical features might, in addition to quantitative patterns, display topographically different patterns of atrophy. METHODS: We adopted a morphometric approach to monitor the pattern of atrophy of the hippocampus and the ERC by computing two-dimensional profiles from MRI volumes of the structures in control subjects and patients with FTD and AD. RESULTS: Compared with control subjects, atrophy of the hippocampus in patients with AD was diffuse. In patients with FTD, atrophy of the hippocampus was localized predominantly in the anterior hippocampus, suggesting a different pattern of hippocampal atrophy in FTD compared with AD. The amount and pattern of atrophy of the entorhinal cortex was virtually equal in both demented groups. CONCLUSIONS: This study provides novel data on the nature of medial temporal lobe atrophy in FTD. Morphometric MRI may be a useful technique for characterizing different patterns of atrophy in primary degenerative dementias in vivo.

Aged↗

PubMed2000

Expression of cell adhesion complexes in epithelial cells seeded on biomaterial surfaces.

Clinical studies indicate that soft tissue responses around dental implants vary, depending on the material used. It is therefore also possible that there are differences in how epithelial cells attach to various biomaterial surfaces. We studied the adhesion of cultured epithelial cells to five different dental material surfaces and to glass. The efficacy of adhesion was evaluated by using scanning electron microscopy (SEM) and immunofluorescence microscopy (IF) with antibodies to vinculin and alpha(6)beta(4) integrin, two cell surface molecules that are functional in epithelial cell adhesion. Our results indicate that epithelial cells adhere and spread more avidly on metallic surfaces (titanium, Ti(6)Al(4)V titanium alloy, dental gold alloy) than on ceramic surfaces (dental porcelain, aluminum oxide). As revealed by SEM, cells on metallic surfaces had a flattened morphology and formed multicellular islands. On porcelain and aluminum oxide most cells were round and adhesion occurred as single cells. Surface coverage was over twofold on metallic surfaces as compared to ceramic surfaces. IF of cells grown on metallic surfaces revealed vinculin in well-organized focal contacts and alpha(6)beta(4) integrin in punctate patterns typical of prehemidesmosomes. On porcelain and aluminum oxide surfaces the cells were mostly round and showed less well-organized adhesion complexes. Our results indicate that smooth metallic biomaterial surfaces are optimal for epithelial cell adhesion and spreading. These findings may have clinical implications in the design of transgingival implant structures.

Alloys↗

PubMed2000

Quantitative MRI of the hippocampus and amygdala in severe depression.

BACKGROUND: There is little evidence to support possible structural changes in the amygdala and hippocampus of patients with severe depression. METHODS: Quantitative MRI of the amygdala and hippocampus, as well as proton spectroscopy (MRS) of mesial temporal structures were studied in 34 drug-resistant in-patients with major depression and compared with 17 age-matched controls. Volumetric MRI data were normalized for brain size. RESULTS: The volume of the left hippocampus was significantly smaller in the patients compared with the controls. Both groups exhibited similar significant hippocampal asymmetry (left smaller than right). The patients, but not the controls, had significant asymmetry of the amygdalar volumes (right smaller than left). No differences were observed between the patients and controls in the T2 relaxation times for the hippocampus and amygdala. Mesial temporal lobe MRS revealed a significantly elevated choline/creatine ratio in the patients compared with the controls. CONCLUSIONS: This quantitative MRI study provides support for a possible association between structural and biochemical substrates and severe drug-resistant major depression.

Adult↗