[Defining the epileptogenic focus].
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Brain Mapping↗
Biomedical subjects
J Partanen
Publications and source records attributed to J Partanen.
[Arrhythmias in acute poisonings].
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Acute Disease↗
Reduced mismatch negativity (MMN) suggests deficits in pre-attentive auditory processing in distractible children.
Mismatch negativity (MMN) event-related brain potential reflects the brain's automatic auditory change detection mechanism that depends on integrity of the auditory sensory memory. We studied MMN in easily distractible (n = 20) and in non-distractible (n = 20) healthy 9-year-old children. Two MMN phases were revealed in both groups: an earlier MMN peak at approximately 220 ms and a later negative slope approximately 300-500 ms after stimulus presentation. The results suggested a strong frontal lobe contribution in the generation of the later MMN phase, and this response was significantly reduced in amplitude in the distractible children. The present findings suggest that distractible children may have deficits in the frontally mediated aspects of auditory sensory memory.
Attention Deficit Disorder with Hyperactivity↗
Persistent frontal P300 brain potential suggests abnormal processing of auditory information in distractible children.
The P300 event-related potential (ERP) was studied at the beginning, in the middle, and at the end of an auditory stimulus discrimination task in 70 normal 9-year-old children. Easily distractible children showed frontally a short-latency P300 response to target stimuli throughout the task, whereas in the non-distractible children the corresponding response was distinctly smaller and also showed a tendency to decrease in size towards the end of the task. The short-latency frontal P300 response reflects activation of the brain's orienting networks, and it normally decreases in size when stimuli lose their 'novelty value' with stimulus repetition. Persistent frontal P300 suggest that distractible children continued to show enhanced orienting to stimuli that should have already been well encoded and/or categorized.
Acoustic Stimulation↗
Vigabatrin, a gabaergic antiepileptic drug, causes concentric visual field defects.
OBJECTIVE: To determine whether there is a causal link between vigabatrin treatment and concentric visual field defects and to evaluate the prevalence of these visual field constrictions. BACKGROUND: While the GABAergic antiepileptic drug (AED) vigabatrin was being clinically developed, only rare cases (less than 1:1000) of symptomatic visual field constriction and retinal disorders were reported. During 1997 to 1998, concentric visual field constrictions were described in case reports of mostly drug-resistant epilepsy patients receiving vigabatrin concurrently with other AEDs. METHODS: Ophthalmologic tests including Goldmann perimetry were performed on 32 adult patients on long-term successful vigabatrin monotherapy (treatment duration 29 to 119 months) and on 18 patients on carbamazepine monotherapy (treatment duration 32 to 108 months). Eighteen healthy adults served as controls. RESULTS: None of the patients complained about vision problems when asked to participate into the study. Thirteen out of the 32 (40%) epilepsy patients treated with vigabatrin monotherapy had concentrically constricted visual fields (9% severely, 31% mildly constricted), whereas none of the carbamazepine monotherapy patients or normal controls presented with a visual field defect (chi-square test, p = 0.0001). The extents of the visual fields were significantly constricted in vigabatrin group as compared with the visual fields of the patients in carbamazepine group or healthy controls (analysis of variance, Scheffe F-test, significant at 99%). CONCLUSIONS: The use of vigabatrin seems to increase the risk of a unique and specific pattern of bilateral, mainly asymptomatic visual field constriction. This risk should be considered when using vigabatrin. Visual field testing should also be performed before treatment and during routine follow-up for patients on vigabatrin.
Adolescent↗
What does the P300 brain response measure in children? New insight from stimulus sequence studies.
The decrease in the P300 brain response latency with increasing age is often taken to reflect maturation of cognitive processes in children. We found that in abnormally distractible children the auditory P300 latency decreased significantly when the inter-target interval (ITI) increased in a stimulus discrimination task. We speculate that the sensory memory trace of the target stimulus may decay in distractible children during longer ITIs, and consequently the next target stimulus may activate the brain's orienting networks that are known to generate shorter latency brain responses. The relative strength by which the functionally different neural networks underlying the cognitive brain responses are activated may contribute significantly to the latency measures of these responses. The presumption that a short P300 latency equals to fast processing may thus be over-simplistic, especially in children.
Acoustic Stimulation↗
Distractible children show abnormal orienting to non-attended auditory stimuli.
Event-related potentials were recorded in response to intermittently presented, non-attended trains of identical auditory stimuli in healthy 9-year-old children. In abnormally distractible children (n =24), the first tone in each train elicited a significantly larger N1 vertex response than in the non-distractible children (n 24), suggesting that increased distractibility may be associated with an abnormally strong cerebral orienting towards non-attended stimuli. A later negativity at around 300 ms, which increases in amplitude with stimulus repetition and may thus reflect the building up of a functional neuronal representation of the stimulus properties, was significantly smaller in the distractible than in the non-distractible children. These findings demonstrate that event-related potential measures may be useful in helping to understand the information processing found in distractible children.
Acoustic Stimulation↗
Effects of acute alcohol infusion on duration and dispersion of QT interval in male patients with coronary artery disease and in healthy controls.
BACKGROUND AND HYPOTHESIS: Alcohol consumption may have advantageous epidemiologic effects but ethanol also increases the risk of sudden coronary death. Prolongation of QT interval has been reported in chronic alcoholics. Long QT period predisposes to serious arrhythmias, and therefore we studied whether acute alcohol intoxication prolongs repolarization in patients with stable coronary artery disease (CAD). METHODS: The effects of acute ethanol steady-state intravenous infusion (0.72 g/kg body weight within 60 min) on QT interval and QT dispersion, assessed by 12-lead electrocardiograms (ECG), were studied in 22 men with stable CAD and in 10 controls. Heart rate variability was measured by Holter recordings. RESULTS: Mean blood alcohol rose to 26.1 +/- 4.3 mmol/l(1.2 +/- 0.2/1000), and was maintained for 2 h. Heart rate was 56 +/- 7 beats/min before and 54 +/- 8 beats/min during ethanol infusion (NS). The heart rate-adjusted QT interval increased on the average 13-23 ms over the 12-lead ECG (p < 0.005). The QT dispersion remained unaltered. The was no difference in the repolarization response in the patients with CAD compared with the controls. The high- and low-frequency components of heart rate variability remained unaltered. CONCLUSIONS: In middle aged men, regardless of the presence of CAD, moderate amounts of alcohol cause prolongation of ventricular repolarization. Changes in the activity of the autonomic nervous system do not seem to explain the observed phenomenon.
Adult↗
Functions of Tie1 and Tie2 receptor tyrosine kinases in vascular development.
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Animals↗
Estimation of the dynamics of event-related desynchronisation changes in electroencephalograms.
A method for the estimation of medium rate transitions of non-stationary electroencephalograms (EEG) is proposed. The method is applicable to such EEG dynamics that are between (a) fast transitions for which segmentation procedures are used and (b) slow transitions for which adaptive filters work properly. The estimation of the transition dynamics is based on a novel time-varying autoregressive model. This model belongs to the class of deterministic regression time-varying autoregressive models and its parametrisation allows only simultaneous transitions in all coefficient evolutions. Data from 22 patients was analysed. The performance of the method is first evaluated with realistic simulations of known transition dynamics and it is shown to be able to track medium-rate transitions. The method is then applied to the estimation of the dynamics of event related desynchronisation. It is shown that the proposed method is able to estimate the transitions which are less apparent, such as from a multi-infarct patient.
Algorithms↗
Back and hip extensor muscle function during therapeutic exercises.
BACKGROUND: Therapeutic exercises are widely used in the treatment of low back problems. Clinical knowledge about targeting the load in these exercises, however, is insufficient. This study assessed the L2 and L5 level paraspinal and gluteus maximus muscle activities in different therapeutic exercises. Intramuscular and surface electromyography (EMG) measurements were obtained to study whether surface EMG measurements can be used in the assessment of multifidus muscle function. METHODS: Eleven healthy subjects (5 men, 6 women) 21 to 38 years of age volunteered for the study. The subjects performed 18 different therapeutic exercises. During the exercises paraspinal EMG was recorded using fine wire and surface electrodes. The normalized peak and average muscle EMG activities (percentage of amplitude in maximal voluntary contraction [MVC]) during each task were determined. RESULTS: The correlations between the average intramuscular and surface activities of the normalized EMG (% of MVC) at the L2 and L5 levels were .928 and .950, respectively. The peak and average EMG amplitudes of the exercises were below 50% and 25% of MVC, respectively. At the L5 level, the multifidus peak and average EMG amplitudes (% MVC) were higher in women than in men, whereas no significant difference was found at the L2 level. In women, the normalized multifidus EMG amplitude was higher at the L5 level than at the L2 level, whereas no significant difference was found in men. In both sexes, the normalized EMG amplitude was higher in the multifidus than in the longissimus muscle. CONCLUSION: Surface EMG measurements may be used in the assessment of multifidus muscle function. Simple therapeutic exercises are effective in activating the lumbar paraspinal muscles.
Adult↗
P300 sequence effects differ between children and adults for auditory stimuli.
Variation of the P300 component was studied in normal children and adults during an auditory oddball paradigm. In children, the target stimuli that were preceded by a large number of standard stimuli elicited about twice as large P300 with a significantly shorter latency, a more widespread distribution, and an earlier positivity in the frontal area than those that were preceded by a small number of standard stimuli. The P300 variation was not as marked in adults as in children. Based on the context updating theory of the P300, the finding suggests that a long intertarget interval (ITI) results in a profound decay of the neural representation of the target stimulus in children; consequently, more resources are needed to update the neural representation, and the target may even be processed as a novel input. The P300 variation may provide information about the brain functions related to memory, attention, and orienting in children. This variation should be considered when assessing cognitive brain functions with event-related potentials in children.
Adult↗
Celiac disease and autoimmune endocrinologic disorders.
Patients with insulin-dependent diabetes mellitus, autoimmune thyroid disease, Addison's disease, and alopecia areata are at increased risk of celiac disease. We investigated whether patients with more than one autoimmune endocrinologic disorder are even more susceptible to celiac disease or have celiac-type mucosal inflammation. All 62 patients found to have such multiple diseases in 1994-1996 were investigated. Small bowel biopsy was performed on all voluntary nonceliac subjects. The villous structure and density of intraepithelial lymphocytes were examined, and HLA-DQ alleles were determined. Seven (11%) patients had celiac disease: six cases were detected earlier and there was one new case; in addition, two had minor villous deterioration and five an increased density of mucosal intraepithelial gammadelta+ T-cells. HLA-DQ2 or DQ8 alleles were found in all subjects with mucosal changes. Patients with multiple autoimmune disorders clearly run an increased risk of developing celiac disease, and some of them have minor mucosal changes compatible with the early signs of the disease.
Addison Disease↗
CD28/CTLA4 gene region on chromosome 2q33 confers genetic susceptibility to celiac disease. A linkage and family-based association study.
Celiac disease (CD) is a common small intestinal injury caused by sensitivity to gliadin in genetically-predisposed individuals. The only susceptibility locus established is the HLA-DQ. We tested whether the chromosomal region of the CD28/CTLA4 genes on 2q33 is linked to CD. These genes encode receptors regulating the T-lymphocyte activation. Recently, this gene region was reported to be linked to the susceptibility to many autoimmune diseases, including insulin-dependent diabetes (IDDM12locus). It is thus an obvious candidate locus also for CD, since the intestinal injury is mediated by the immune system. Genetic linkage between seven marker loci in this gene region and CD was studied in 69 Finnish families. In the multipoint linkage analysis, the highest non-pararametric linkage score (NPL) was 1.75 (P=0.04) for D2S116, suggesting weak linkage for this candidate locus. To evaluate this finding, an additional 31 families were typed for all markers. In the combined set of 100 families the NPL score for marker D2S116 was 2.55 (P=0.006) and for other markers 1.90-2.47 (P=0.029-0.007), supporting genuine linkage at this region. Significantly, locus D2S116 also showed a clear allelic association in these 100 families (P=0.0001). The transmission/disequilibrium test (TDT) for locus D2S116 gave preliminary evidence for preferential maternal non-transmission of allele *136 to patients (TDTmax=8.3; P<0.05). No paternal deviation was found suggesting that the effect of the locus might be mediated by a sex-dependent factor protective against CD. Our results indicate that the CD28/CTLA4 gene region can contain a novel susceptibility locus for CD and support the hypothesis that CD has an immune system-mediated component. Like the HLA, the CD28/CTLA4 genes appear to be associated with genetic susceptibility to various autoimmune diseases.
Abatacept↗
Genome scan for predisposing loci for distal interphalangeal joint osteoarthritis: evidence for a locus on 2q.
The genetic contribution to common forms of osteoarthritis (OA) is well established but poorly understood. We performed a genome scan, using 302 markers for loci predisposing to distal interphalangeal joint (DIP) OA. To minimize genetic heterogeneity in our study sample, we identified siblings with a severe, radiologically defined phenotype from the nationwide registers of Finland. In the initial genome scan, linkage analysis in 27 sibships gave a pairwise LOD score (Z) >1.00 with nine of the screening markers. In the second stage, additional markers and family members were genotyped in these chromosomal regions. On 2q12-q13, IL1R1 resulted in Z=2.34 at recombination fraction (theta) 0, allowing a dominant mode of inheritance. Association analysis of markers D2S2264, IL1R1, D2S373, and D2S1789 jointly provided some evidence for a shared haplotype among the affected individuals (P value of.012). Also, multipoint nonparametric linkage analysis yielded a P value of.0001 near the locus IL1R1 and P=.0007 approximately 20 cM telomeric near marker D2S1399, which, in two-point analysis, gave Z=1.48 (straight theta=. 02). This chromosomal region on 2q harbors the interleukin 1 gene cluster and, thus, represents a good candidate region for inflammatory and autoimmune disorders. Three additional chromosomal regions-4q26-q27, 7p15-p21, and Xcen-also provided some evidence for linkage, and further analyses would be justified to clarify their potential involvement in the genetic predisposition to DIP OA.
Adult↗
HLA-DQ alleles and human papillomavirus DNA in adult-onset laryngeal papillomatosis.
Sixty-two patients with histologically confirmed adult-onset laryngeal papilloma were clinically examined; their HLA class II DQA1 and DQB1 alleles and the presence and type of human papillomavirus (HPV) in their laryngeal papilloma biopsies were determined by polymerase chain reaction-based methods. No differences in the DQA1 or DQB1 frequencies appeared between the patients as a group and the reference population. When the patients were divided into groups according to number of laryngeal procedures performed, no HLA association was noticed with any group, nor did the presence of HPV-6 or HPV-11 DNA in the laryngeal specimen correlate with HLA type. A suggestive association was found between the DQB1 *0501 allele and the 16 patients whose laryngeal biopsy was HPV-negative, but because of the small series, additional patients need to be studied. Earlier, the DQB1 *0501 allele was reported to be protective against cervical cancer, another HPV-associated disease.
Adolescent↗
Celiac disease and markers of celiac disease latency in patients with primary Sjögren's syndrome.
OBJECTIVE: Many autoimmune diseases occur concomitantly with celiac disease. We investigated prospectively the occurrence of celiac disease and small-bowel mucosal inflammation in patients with primary Sjögren's syndrome. METHODS: A total of 34 patients with primary Sjögren's syndrome and 28 controls underwent small bowel biopsy. Villous morphology, jejunal intraepithelial lymphocytes, and mucosal HLA-DR were evaluated and DQA and DQB alleles, serum antiendomysial, and antigliadin antibodies were examined. RESULTS: Five (14.7%) of 34 Sjögren's syndrome patients were found to have celiac disease. The density of jejunal intraepithelial gammadelta+ T cells was increased in all celiac and in four nonceliac patients. All celiac patients, 69% of nonceliac Sjögren's syndrome patients, and 11% of control subjects showed enhanced HLA-DR expression (p < 0.001). HLA DQ2 was present in 19 (56%) patients with Sjögren's syndrome, including all five with celiac disease. CONCLUSIONS: The findings show a close association between Sjögren's syndrome and celiac disease. Even among nonceliac patients with primary Sjögren's syndrome, an ongoing inflammation is often present in the small bowel mucosa.
Autoimmune Diseases↗