Variation in carbon and nitrogen concentrations among peatland categories at the global scale

Peatlands account for 15 to 30% of the world's soil carbon (C) stock and are important controls over global nitrogen (N) cycles. However, C and N concentrations are known to vary among peatlands contributing to the uncertainty of global C inventories, but there are few global studies that relate peatland classification to peat chemistry. We analyzed 436 peat cores sampled in 24 countries across six continents and measured C, N, and organic matter (OM) content at three depths down to 70 cm. Sites were distinguished between northern (387) and tropical (49) peatlands and assigned to one of six distinct broadly recognized peatland categories that vary primarily along a pH gradient. Peat C and N concentrations, OM content, and C:N ratios differed significantly among peatland categories, but few differences in chemistry with depth were found within each category. Across all peatlands C and N concentrations in the 10-20 cm layer, were 440 ± 85.1 g kg-1 and 13.9 ± 7.4 g kg-1, with an average C:N ratio of 30.1 ± 20.8. Among peatland categories, median C concentrations were highest in bogs, poor fens and tropical swamps (446-532 g kg-1) and lowest in intermediate and extremely rich fens (375-414 g kg-1). The C:OM ratio in peat was similar across most peatland categories, except in deeper samples from ombrotrophic tropical peat swamps that were higher than other peatlands categories. Peat N concentrations and C:N ratios varied approximately two-fold among peatland categories and N concentrations tended to be higher (and C:N lower) in intermediate fens compared with other peatland types. This study reports on a unique data set and demonstrates that differences in peat C and OM concentrations among broadly classified peatland categories are predictable, which can aid future studies that use land cover assessments to refine global peatland C and N stocks.

Decreased Gray-White Matter Contrast of [11C]-PiB Uptake in Cognitively Unimpaired Subjects with Severe Obstructive Sleep Apnea

BACKGROUND

Very recently, cognitively normal, middle-aged adults with severe obstructive sleep apnea (OSA) were shown to have regional cortical amyloid-β deposits. In the normal brain, amyloid tracer (e.g., [11C]-PiB) uptake is observed in white matter (WM) but not in cortical gray matter (GM), resulting in clear GM-WM contrast. There are no reports on possible changes in this contrast in severe OSA.

OBJECTIVES

Evaluate changes in the global [11C]-PiB GM-WM contrast and study if factors reflecting clinical and imaging characteristics are associated with them.

DESIGN AND SETTING

Cross-sectional imaging study.

PARTICIPANTS

19 cognitively intact middle-aged (mean 44 years) patients with severe OSA (Apnea-Hypopnea Index >30/h), carefully selected to exclude any other possible factors that could alter brain health.

MEASUREMENTS

Detailed neuroimaging (amyloid PET, MRI). Signs of possible alterations in amyloid tracer GM-WM contrast and kinetics were studied with static and dynamic [11C]-PiB PET and WM structures with detailed 3.0T MRI.

RESULTS

Static [11C]-PiB PET uptake showed significantly decreased GM-WM contrast in 5 out of 19 patients. This was already clearly seen in visual evaluation and also detected quantitatively using retention indexes. Dynamic imaging revealed decreased contrast due to alterations in trace accumulation in the late phase of [11C]-PiB kinetics. Decreased GM-WM contrast in the late phase was global in nature. MRI revealed no corresponding alterations in WM structures. Importantly, decreased GM-WM contrast was associated with smoking (p = 0.007) and higher Apnea-Hypopnea Index (p = 0.001).

CONCLUSIONS

Severe OSA was associated with decreased GM-WM contrast in amyloid tracer uptake, with significant correlation with clinical parameters of smoking and AHI. The results support and further extend the current understanding of the deleterious effect of severe OSA on proper amyloid clearance, possibly reflecting dysfunction of the brain glymphatic system.

Feasibility of mapping breast cancer with supine breast MRI in patients scheduled for oncoplastic surgery

OBJECTIVES

To prospectively determine the feasibility of preoperative supine breast MRI in breast cancer patients scheduled for oncoplastic breast-conserving surgery.

METHODS

In addition to a diagnostic prone breast MRI, a supplementary supine MRI was performed with the patient in the surgical position including skin markers. Tumours' locations were ink-marked on the skin according to findings obtained from supine MRI. Changes in tumours' largest diameter and locations between prone and supine MRI were measured and compared to histology. Nipple-to-tumour and tumour-to-chest wall distances were also measured. Tumours and suspicious areas were surgically removed according to skin ink-markings. The differences between MRI measurements with reference to histopathology were evaluated with the paired-sample t test.

RESULTS

Fourteen consecutive patients, 15 breasts and 27 lesions were analysed. Compared to histology, prone MRI overestimated tumour size by 47.1% (p = 0.01) and supine MRI by 14.5% (p = 0.259). In supine MRI, lesions' mean diameters and areas were smaller compared to prone MRI (- 20.9%, p = 0.009 and - 38.3%, p = 0.016, respectively). This difference in diameter was more pronounced in non-mass lesions (- 31.2%, p = 0.031) compared to mass lesions (- 9.2%, p = 0.009). Tumours' mean distance from chest wall diminished by 69.4% (p < 0.001) and from nipple by 18.2% (p < 0.001). Free microscopic margins were achieved in first operation in all patients.

CONCLUSIONS

Supine MRI in the surgical position is feasible and useful in the precise localisation of prone MRI-detected lesions and provides a helpful tool to implement in surgery. Supine MRI more accurately determines tumours' size and location and might have an important role to diminish overestimations.

KEY POINTS

• Breath-hold supine breast MRI is feasible using commercially available coils and sequences. • Size and area of lesions on MRI were consistently smaller when measured from the supine position as compared to the prone position. • Supine breast MRI is useful in the precise preoperative localisation of prone MRI-detected lesions. •.

Radiographic Changes in the Condyle of the Temporomandibular Joint in Psoriatic Arthritis

One hundred and ten patients with psoriatic arthritis (PA) and 100 matched control patients were examined by using ***orthopan-tomography to discover radiographic changes in the condyle of the temporomandibular joint (TMJ). Thirty-one per cent of the PA patients and 13 per cent of the control patients had radiographic changes in the condyle of the TMJ. The most common radiographic finding in PA patients was unilateral erosion of the condyle. Of the radiographic changes in the PA group, cortical erosions correlated negatively with age, whereas osteophytes correlated positively with the duration of PA.

In Vivo MRI Measurement of Spinal Cord Displacement in the Thoracolumbar Region of Asymptomatic Subjects with Unilateral and Sham Straight Leg Raise Tests

Background

Normal displacement of the conus medullaris with unilateral and bilateral SLR has been quantified and the "principle of linear dependence" has been described.

Purpose

Explore whether previously recorded movements of conus medullaris with SLRs are i) primarily due to transmission of tensile forces transmitted through the neural tissues during SLR or ii) the result of reciprocal movements between vertebrae and nerves.

Study design

Controlled radiologic study.

Methods

Ten asymptomatic volunteers were scanned with a 1.5T magnetic resonance (MR) scanner using T2 weighted spc 3D scanning sequences and a device that permits greater ranges of SLR. Displacement of the conus medullaris during the unilateral and sham SLR was quantified reliably with a randomized procedure. Conus displacement in response to unilateral and sham SLRs was quantified and the results compared.

Results

The conus displaced caudally in the spinal canal by 3.54±0.87 mm (mean±SD) with unilateral (p≤.001) and proximally by 0.32±1.6 mm with sham SLR (p≤.542). Pearson correlations were higher than 0.99 for both intra- and inter-observer reliability and the observed power was 1 for unilateral SLRs and 0.054 and 0.149 for left and right sham SLR respectively.

Conclusions

Four relevant points emerge from the presented data: i) reciprocal movements between the spinal cord and the surrounding vertebrae are likely to occur during SLR in asymptomatic subjects, ii) conus medullaris displacement in the vertebral canal with SLR is primarily due to transmission of tensile forces through the neural tissues, iii) when tensile forces are transmitted through the neural system as in the clinical SLR, the magnitude of conus medullaris displacement prevails over the amount of bone adjustment.

Sensorimotor, visual, and auditory cortical atrophy in Unverricht-Lundborg disease mapped with cortical thickness analysis

BACKGROUND AND PURPOSE

EPM1, caused by mutations in the CSTB gene, is the most common form of PME. The most incapacitating symptom of EPM1 is action-activated and stimulus-sensitive myoclonus. The clinical severity of the disease varies considerably among patients, but so far, no correlations have been observed between quantitative structural changes in the brain and clinical parameters such as duration of the disease, age at onset, or myoclonus severity. The aim of this study was to evaluate possible changes in CTH of patients with EPM1 compared with healthy controls and to correlate those changes with clinical parameters.

MATERIALS AND METHODS

Fifty-three genetically verified patients with EPM1 and 70 healthy volunteers matched for age and sex underwent 1.5T MR imaging. T1-weighted 3D images were analyzed with CTH analysis to detect alterations. The patients were clinically evaluated for myoclonus severity by using the UMRS. Higher UMRS scores indicate more severe myoclonus.

RESULTS

CTH analysis revealed significant thinning of the sensorimotor and visual and auditory cortices of patients with EPM1 compared with healthy controls. CTH was reduced with increasing age in both groups, but in patients, the changes were confined specifically to the aforementioned areas, while in controls, the changes were more diffuse. Duration of the disease and the severity of myoclonus correlated negatively with CTH.

CONCLUSIONS

Cortical thinning in the sensorimotor areas in EPM1 correlated significantly with the degree of the severity of the myoclonus and is most likely related to the widespread stimulus sensitivity in EPM1.

Functional MRI and motor behavioral changes obtained with constraint-induced movement therapy in chronic stroke

BACKGROUND

The clinical benefits of intensive stroke rehabilitation vary individually. We used multimodal functional imaging to assess the relationship of clinical gain and imaging changes in patients with chronic stroke whose voluntary motor control improved after constraint-induced movement therapy (CIMT).

METHODS

Eleven patients (37.6 ± 36.8 months from stroke) were studied by functional MRI (fMRI), transcranial magnetic stimulation (TMS), and behavioral assessment of hand motor control (Wolf Motor Function Test) before and after 2 weeks of CIMT. Individual and group-level changes in imaging and behavioral parameters were investigated.

RESULTS

Increase in fMRI activation in the sensorimotor areas was greater amongst those subjects who had poor hand motor behavior before therapy and/or whose motor behavior improved notably because of therapy than amongst subjects with relatively good motor behavior already before therapy. The magnitude of CIMT-induced changes in task-related fMRI activation differed between lesioned and non-lesioned hemispheres, and the fMRI laterality index was different for paretic and non-paretic hand tasks. The corticospinal conduction time in TMS was significantly decreased after CIM therapy.

CONCLUSIONS

Alterations in sensorimotor cortical activations (fMRI) and corticospinal conductivity (TMS) were observed after intensive rehabilitation in patients with chronic stroke. Activation and functional changes in fMRI and TMS correlated significantly with the degree of clinical improvement in hand motor behavior. The present data advance the understanding of the functional underpinnings of motor recovery, which may be obtained even years after the stroke.

Cerebellar apparent diffusion coefficient changes in patients with supratentorial ischemic stroke

OBJECTIVES

To evaluate apparent diffusion coefficient (ADC) in cerebellar subregions in patients with stroke.

MATERIALS AND METHODS

The total counts and ADCs were bilaterally measured on cerebellar white matter, gray matters of medial (G1), intermediate (G2), and lateral zones (G3) on SPECT and ADC maps from 20 patients with supratentorial ischemic stroke within the first 48 h and on day 8 after onset. ADCs were also obtained from 15 age-matched controls.

RESULTS

Within 48 h, the ADCs were significantly increased bilaterally in the G3, and tended to be increased bilaterally in the white matter and G1, and contralateral G2 compared with controls. On day 8, the ADCs were significantly increased in all contralateral cerebellar subregions and in ipsilateral G1 and G2, and tended to be increased in ipsilateral G3. The ADC value was significantly higher in contralateral than in ipsilateral white matter on day 8. The interhemispheric asymmetry indices (AIs) of ADC and SPECT were significantly associated with each other in G2 and G3 within 48 h, but not on day 8. The AIs of ADC and SPECT were significantly related to each other in the G3 within 48 h and on day 8.

CONCLUSIONS

Supratentorial ischemic stroke may cause mild cerebellar vasogenic edema.

Bruxism is associated with nicotine dependence: a nationwide Finnish twin cohort study

OBJECTIVES

To investigate the association of smoking with bruxism while controlling for genetic and environmental factors using a co-twin-control design. Especially, the role of nicotine dependence was studied in this context.

METHODS

The material derives from the Finnish Twin Cohort consisting of 12,502 twin individuals who responded to a questionnaire in 1990 (response rate of 77%). All were born in 1930-1957, the mean age being 44 years. The questionnaire covered 103 multiple choice questions, 7 dealing with tobacco use and 22 with sleep and vigilance matters, including perceived bruxism. In addition, a subsample derived from the Nicotine Addiction Genetics Finland Study containing 445 twin individuals was studied.

RESULTS

In age- and gender-controlled multinomial logistic regression, both monthly and rarely reported bruxism associated with both current cigarette smoking (odds ratio [OR] = 1.74 and 1.64) and former cigarette smoking (OR = 1.64 and 1.47). Weekly bruxism associated with current smoking (OR = 2.85). Current smokers smoking 20 or more cigarettes a day reported weekly bruxism more likely (OR = 1.61-1.97) than those smoking less. Among twin pairs (N = 142) in which one twin was a weekly bruxer and the cotwin a never bruxer, there were 13 monozygotic pairs in which one twin was a current smoker and the other twin was not. In all cases, the bruxer was the smoker (p = .0003). Nicotine dependence associated significantly with bruxism.

CONCLUSIONS

Our twin study provides novel evidence for a possible causal link between tobacco use and bruxism among middle-aged adults. Nicotine dependence may be a significant predisposing factor for bruxism.

Atrophic enlargement of CSF volume after subarachnoid hemorrhage: correlation with neuropsychological outcome

BACKGROUND AND PURPOSE

Ventricular dilation and sulcal enlargement are common sequelae after aSAH. Our aim was to quantify the late ventricular dilation and volumes of the CSF spaces after aSAH and to determine if they correlate with neurologic and cognitive impairments frequently detected in these patients.

MATERIALS AND METHODS

3D T1-weighted images needed for volumetry were available in 76 patients 1 year after aSAH, along with 75 neuropsychological assessments. Volumes of CSF segments and ICV were quantified by SPM in 76 patients and 30 control subjects to determine CSF/ICV ratios. The mCMI was calculated to roughly evaluate the ventricular dilation. The contributing factors for enlarged ventricles and CSF volumes were reviewed from radiologic, clinical, and neuropsychological perspectives.

RESULTS

The mCMI was higher in patients with aSAH (0.23 +/- 0.06) compared with control subjects (0.20 +/- 0.04; P = .020). In line with these planimetric measurements, the SPM-based CSF/ICV ratios were higher in patients with aSAH (35.58 +/- 7.0) than in control subjects (30.36 +/- 6.25; P = .001). Preoperative hydrocephalus, higher HH and Fisher grades, and focal parenchymal lesions on brain MR imaging, but not the treatment technique, were associated with ventricular enlargement. The clinical outcome and presence of neuropsychological deficits correlated significantly with CSF enlargement.

CONCLUSIONS

Ventricular and sulcal enlargement, together with reduced GM volumes, after aSAH may indicate general atrophy rather than hydrocephalus. Enlarged CSF spaces correlate with cognitive deficits after aSAH. A simple measure, mCMI proved to be a feasible tool to assess the diffuse atrophic brain damage after aSAH.

Non-primary motor areas in the human frontal lobe are connected directly to hand muscles

Structural studies in primates have shown that, in addition to the primary motor cortex (M1), premotor areas are a source of corticospinal tracts. The function of these putative corticospinal neuronal tracts in humans is still unclear. We found frontal non-primary motor areas (NPMAs), which react to targeted non-invasive magnetic pulses and activate peripheral muscles as fast as or even faster than those in M1. Hand muscle movements were observed in all our subjects about 20 ms after transcranial stimulation of the superior frontal gyrus (Brodmann areas 6 and 8). Stimulation of NPMA could activate both proximal and distal upper limb muscles with the same delay as a stimulation of the M1, indicating converging motor representations with direct functional connections to the hand. We suggest that these non-primary cortical motor representations provide additional capacity for the fast execution of movements. Such a capacity may play a role in motor learning and in recovery from motor deficits.

Efficient reduction of stimulus artefact in TMS-EEG by epithelial short-circuiting by mini-punctures

OBJECTIVE

We aimed at comparing the effects of two different electrode-to-skin contact preparation techniques on the stimulus artefact induced by transcranial magnetic stimulation (TMS) in electroencephalography (EEG) signals.

METHODS

Six healthy subjects participated in a combined navigated brain stimulation (NBS) and EEG study. Electrode contacts were first prepared in the standard way of rubbing the skin using a wooden stick with a cotton tip. The location of hand motor area and the motor threshold (MT) was determined for each subject. Then, the TMS-induced artefact was measured at 60%, 80%, 100% and 120% of the MT. Subsequently, the epithelium under the electrode contacts was electrically short-circuited by puncturing with custom-made needles and the stimulation sequences were replicated. The artefact was compared between the preparation techniques.

RESULTS

The TMS-induced artefact was significantly reduced after puncturing. In addition, the size and duration of the artefact depended on the applied stimulation intensity. The reduction of the artefact was largest in electrodes at and close to the stimulation site.

CONCLUSIONS

Mini-puncturing technique enables more accurate analysis of TMS-induced short-latency phenomena in EEG during NBS, and it may aid in the examination of the short distance neural connectivity beneath and close to the stimulation site.

SIGNIFICANCE

This study describes a practical skin preparation method that significantly improves the utility of TMS-EEG method in studying short-latency cortical connectivity.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.