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Oili Salonen

Publications and source records attributed to Oili Salonen.

At least 19 recordsLinked to original sources
PubMed2006

Induced hypertension for the treatment of acute MCA occlusion beyond the thrombolysis window: case report.

BACKGROUND: A minority of stroke patients is eligible for thrombolytic therapy. Small pilot case series have hinted that elevation of incident arterial blood pressure might be associated with a favorable prognosis either in acute or subacute stroke. However, these patients were not considered for thrombolytic therapy and were not followed - up systematically. We used pharmacologically induced hypertension in a stroke patient with middle cerebral artery (MCA) occlusion ineligible for thrombolysis that was followed-up by radiological, clinical and functional outcome assessment. CASE PRESENTATION: A patient with acute embolic MCA occlusion producing a large, ischemic penumbra confirmed by perfusion CT was treated by induced hypertension with phenylephrine started within 4 h of admission. Increase in the mean arterial pressure by 20% led to a reduction of neurological deficit by 3 points on the National Institute of Stroke Scale. MRI and CT scans performed during phenylephrine infusion showed the presence of limited subcortical and cortical infarct changes that were clearly less extensive than the perfusion deficit in the brain perfusion CT at baseline, found in the absence of MCA patency. No complications due to induced hypertension therapy occurred. Moderate functional improvement up to modified Rankin scale 2 at follow up took place. CONCLUSION: Induced hypertension in acute ischemic stroke seems clinically feasible and may be beneficial in selected normo- or hypotensive stroke patients not eligible for thrombolytic recanalization therapy.

Acute Disease↗
PubMed2006

Microarray analysis reveals overexpression of CD163 and HO-1 in symptomatic carotid plaques.

OBJECTIVE: We studied by microarray analysis whether symptomatic and asymptomatic carotid plaques from the same patient differ in gene expression and whether the same changes are present in an independent sample set. METHODS AND RESULTS: Carotid plaques from four patients with bilateral high-grade stenosis, one being symptomatic and the other asymptomatic, were analyzed on Affymetrix U95Av2 arrays. 33 genes showed >1.5-fold change between symptomatic and asymptomatic plaques in an intraindividual comparison with FDR ranging from 0.28 to 0.40. Three genes involved in iron-heme homeostasis, CD163, HO-1, and transferrin receptor, were further analyzed in 40 independent plaques. HO-1 (fold-change 1.93, 95%CI 1.04 to 3.94, P=0.040) and CD163 (1.58, 1.11 to 2.40, P=0.013) mRNAs were again induced, and also HO-1 protein was overexpressed in symptomatic plaques (4.38, 1.54 to 12.20, P=0.024). The expression of HO-1 and CD163 correlated with tissue iron content but iron itself was not associated with the symptom status. CONCLUSIONS: Symptomatic plaques show overexpression of CD163 and HO-1 both in intraindividual and interindividual comparison. Their expression correlates with iron deposits but asymptomatic and symptomatic plaques from isolated patients do not differ in macroscopic hemorrhages or iron deposits. We suggest that symptomatic plaques show a more pronounced induction of CD163 and HO-1 in response to plaque hemorrhages.

Aged↗
PubMed2006

Endothelial apoptosis does not determine symptom status in carotid artery disease.

BACKGROUND: We examined the hypothesis that endothelial denudation in advanced carotid plaques (CPs) occurs by increased apoptosis of endothelial cells (ECs) using scanning electron microscopy (SEM) as well as markers of cellular proliferation and apoptosis in advanced symptomatic CPs (SCPs) and asymptomatic CPs (ACPs). METHODS: 93 consecutive patients underwent carotid endarterectomy. Five additional specimens were studied by SEM. We performed TUNEL assays, and immunostaining against Fas receptor (FasR), Fas ligand (FasL), activated caspase 3 (ACA3) and Ki-67. RESULTS: SEM revealed morphological changes consistent with EC detachment. Surprisingly, ACA3 positivity was more pronounced on the endothelium of ACPs (4.6 +/- 0.7% of total EC count) than on SCPs (3.3 +/- 0.7%, p = 0.049), and was found to correlate positively with nuclear Ki-67 expression (r(s) = 0.275, p = 0.040). FasL expression was significantly increased on the endothelium of SCPs compared with ACPs (66.4 +/- 4.4 vs. 53.9 +/- 4.5%, p = 0.047). CONCLUSIONS: Absence of increased positivity of apoptotic markers dismisses apoptosis as a dominant mechanism underlying endothelial detachment of SCPs. Rather, increased ACA3 with co-expression of Ki-67 in ACPs might suggest that renewal of endothelium by active cell turnover may contribute to clinically silent evolution of plaques with preserved EC integrity. These observations may assist in designing novel therapies to prevent endothelial decay and symptom generation in advanced carotid artery disease.

Aged↗
PubMed2006

Selective attention to sound location or pitch studied with fMRI.

We used 3-T functional magnetic resonance imaging to compare the brain mechanisms underlying selective attention to sound location and pitch. In different tasks, the subjects (N = 10) attended to a designated sound location or pitch or to pictures presented on the screen. In the Attend Location conditions, the sound location varied randomly (left or right), while the pitch was kept constant (high or low). In the Attend Pitch conditions, sounds of randomly varying pitch (high or low) were presented at a constant location (left or right). Both attention to location and attention to pitch produced enhanced activity (in comparison with activation caused by the same sounds when attention was focused on the pictures) in widespread areas of the superior temporal cortex. Attention to either sound feature also activated prefrontal and inferior parietal cortical regions. These activations were stronger during attention to location than during attention to pitch. Attention to location but not to pitch produced a significant increase of activation in the premotor/supplementary motor cortices of both hemispheres and in the right prefrontal cortex, while no area showed activity specifically related to attention to pitch. The present results suggest some differences in the attentional selection of sounds on the basis of their location and pitch consistent with the suggested auditory "what" and "where" processing streams.

Acoustic Stimulation↗
PubMed2005

Carotid plaque mast cells associate with atherogenic serum lipids, high grade carotid stenosis and symptomatic carotid artery disease. Results from the helsinki carotid endarterectomy study.

OBJECTIVE: Increased numbers of mast cells (MCs) are present in ruptured coronary plaques, suggesting to play a role in acute coronary syndromes. We evaluated the distribution densities of MCs, macrophages and T cells in carotid plaques and correlated these findings to stroke risk factors as well as history of stroke or TIA. METHODS AND RESULTS: Seventy-eight carotid samples from 75 patients (16 plaques from asymptomatic patients and 62 from patients with recent ischemic symptoms) undergoing carotid endarterectomy with an internal carotid stenosis >70% that were immunostained and quantified for MCs, macrophages and T cells. The MC distribution density showed positive correlation with the degree of carotid stenosis (p = 0.012), serum levels of total cholesterol (p = 0.021), LDL cholesterol (p = 0.013) and triglycerides (p = 0.005), and an inverse correlation with serum HDL cholesterol levels (p = 0.001). The average MC density (p = 0.023), but not the macrophage (p = 0.58) or T cell (p = 0.74) density, was higher in the symptomatic than in the asymptomatic patients. In a comparison of plaques ipsilateral and contralateral to the thromboembolic event, the densities of the three types of inflammatory cells were similar. CONCLUSIONS: Increased MC distribution density is associated with an atherogenic serum lipid profile, high-grade carotid artery stenosis and symptomatic carotid artery disease. These findings suggest a potential involvement of MCs in the pathophysiology of carotid artery stenosis.

Aged↗
PubMed2005

The role of blind humans' visual cortex in auditory change detection.

Several studies using brain imaging have demonstrated occipital-cortex activation in blind individuals during tactile and auditory tasks, suggesting that the visual cortex deprived of its normal input has adopted a new role in information processing. So far, however, at what stages of information processing and to which perceptual sub-processes this applies remains unclear. We determined the auditory functions of this cortical region in early-blind humans by means of functional magnetic resonance imaging. We found that these areas were not activated by the mere presence of sound, but were involved in the attentive processing of changes in the auditory environment, which is important in detecting potentially dangerous or other important events in the surroundings, for example.

Acoustic Stimulation↗
PubMed2005

Test-retest stability of the magnetic mismatch response (MMNm).

OBJECTIVE: We investigated the replicability of the magnetically measured mismatch negativity (MMNm). METHODS: The MMNm was recorded twice by using a 122-channel whole-head magnetometer in 15 healthy young adults. The MMNm responses for duration, intensity and frequency deviants were analyzed separately in left and right hemispheres for the response strength, latency, dipole moment, and generator loci. RESULTS: In the right hemisphere, the test-retest correlations were statistically significant for all MMNm parameters (r = 0.49-0.89). In the left hemisphere, the majority of the MMNm parameters also demonstrated statistically significant test-retest correlations (r = 0.61-0.82). In addition, the MMNm generator loci were stable for all deviants. CONCLUSIONS AND SIGNIFICANCE: The present results are encouraging in terms of both research and clinical use of MMNm in studying human auditory discrimination in its normal and deteriorated states.

Adult↗
PubMed2005

Depression-executive dysfunction syndrome in stroke patients.

OBJECTIVE: It has been suggested that executive dysfunction could be the core defect in patients with geriatric or vascular depression, and that this depression-dysexecutive syndrome (DES) might be related to frontal-subcortical circuit dysfunction. The authors tested this hypothesis in 158 poststroke patients, of whom 21 had both depression and executive dysfunction. METHODS: In this cross-sectional cohort study, a neurological, psychiatric, and neuropsychological examination was carried out 3 months after ischemic stroke, and brain infarcts, white-matter changes, and brain atrophy were recorded by MRI. RESULTS: The 21 patients with DES had significantly more brain infarcts affecting their frontal-subcortical circuit structures than the 137 patients without DES, or the 41 patients with depression but without executive dysfunction. Patients with DES also had more severe depressive symptoms and worse psychosocial functioning, and they coped less well in complex activities of daily living. CONCLUSIONS: DES is a valid concept and may define a subgroup of poststroke patients with frontal-subcortical pathology and with distinct prognosis and treatment options.

Aged↗
PubMed2004

Abnormal intravoxel cerebral blood flow heterogeneity in human ischemic stroke determined by dynamic susceptibility contrast magnetic resonance imaging.

BACKGROUND AND PURPOSE: The determination of cerebral blood flow heterogeneity (FH) by dynamic susceptibility contrast (DSC) magnetic resonance imaging has recently been proposed as a tool to predict final infarct size in acute stroke. In this study, we describe the evolution of FH during the first week as well as its correlation to the patients' clinical status. METHODS: Ten patients with ischemic stroke were studied with DSC MRI and diffusion-weighted imaging in hyperacute (<6 hours) phase, at 24 hours, and 1 week after symptom onset. In addition to intravoxel FH, cerebral blood volume (CBV), cerebral blood flow (CBF), and contrast agent mean transit time (MTT) were determined from DSC MRI. All patients were evaluated neurologically with National Institute of Health Stroke Scale concurrently with the imaging sessions. RESULTS: All patients showed infarct growth, judged by diffusion-weighted imaging, during the week with simultaneous decrease in the sizes of FH, CBV, CBF, and MTT abnormalities. The FH abnormality was shown to be larger than CBV and CBF abnormalities at the hyperacute phase and 24 hours, but smaller than MTT abnormality in all 3 imaging sessions. The sizes of hyperacute FH, CBV, CBF, and MTT abnormalities correlated well with infarct size at 24 hours and at 1 week. Additionally, FH was the only perfusion parameter that correlated with the clinical score. CONCLUSIONS: FH predicts infarct size equally well with the other perfusion parameters but is superior in correlation with the clinical score. FH can easily be incorporated to hyperacute stroke imaging without additional efforts.

Aged↗
PubMed2004

The processing of speech and non-speech sounds in aphasic patients as reflected by the mismatch negativity (MMN).

This study compared the discrimination of speech and non-speech sounds in left-hemisphere stroke patients with aphasia and healthy controls by recording event-related potentials (ERPs) and behavioural responses. It was found that the mismatch negativity (MMN) amplitude for vowel and duration changes in speech sounds was diminished in the patients. In contrast, there was no significant difference between the groups in the MMN for comparable frequency and duration changes in non-speech sounds. In the behavioural session, the patients were slower than the control subjects in discriminating duration changes of both types of sounds. These results suggest that left-hemisphere lesions have differential effects on the discrimination of speech and acoustic features indicating that they have separate neural substrates.

Acoustic Stimulation↗
PubMed2004

Hippocampal volumes in schizophrenic twins.

CONTEXT: The effects of genes and environment on brain abnormalities in schizophrenia remain unclear. OBJECTIVE: To examine the contributions of genes and environment to hippocampal volume reduction in schizophrenia. DESIGN: Population-based twin cohort study. SETTING: Finland. PARTICIPANTS: Seven monozygotic (MZ) twin pairs concordant for schizophrenia and 16 MZ and 32 dizygotic (DZ) twin pairs discordant for schizophrenia, ascertained so as to be representative of all such probands in a Finnish birth cohort, along with 28 MZ and 26 DZ healthy comparison twin pairs without a family history of psychosis. MAIN OUTCOME MEASURES: Hippocampal volume measurements taken from high-resolution magnetic resonance images. RESULTS: Hippocampal volumes of probands were smaller than those of their nonschizophrenic MZ and DZ co-twins and healthy twins. Hippocampal volumes of probands' non-ill co-twins were smaller than those of healthy twins, but those of non-ill MZ and DZ co-twins of schizophrenic patients were similar. The intraclass correlations for hippocampal volumes among healthy and discordant MZ pairs were larger than those among the respective DZ pairs. The intraclass correlation for healthy MZ pairs was larger than that for discordant MZ pairs, and the variance component estimate for additive genetic effects was lower in discordant twins than in healthy twins. CONCLUSIONS: Although hippocampal volume in healthy individuals is largely affected by genetic factors, it is subject to substantially greater modulation by environmental factors in schizophrenic patients and their relatives. The results are discussed in view of assumptions underlying classic twin methods.

Adult↗
PubMed2004

Brain metabolic alterations in patients with type 1 diabetes-hyperglycemia-induced injury.

Microangiopathic end-organ injury is common in type 1 diabetes. However, the pathophysiology of diabetic encephalopathy is poorly understood. The authors studied 10 normotensive patients with type 1 diabetes with retinopathy, autonomic neuropathy, but without nephropathy, and 10 healthy subjects. Proton magnetic resonance spectroscopy was performed at 1.5 T in the frontal cortex, thalamus, and posterior frontal white matter. There was no change in N-acetyl-containing compounds (NA), but choline-containing compounds (Cho) were increased in the white matter and in the thalamus; myo-inositol was increased in the white matter, glucose excess was found in all brain, and water intensity was increased in the cortical voxel in the patients. Calculated lifetime glycemic exposure correlated inversely with Cho and NA in white matter and with Cho in thalamus. Concentrations of soluble intercellular adhesion molecules and vascular cell adhesion molecules were increased in the patients. In conclusion, in patients with type 1 diabetes, the increase in adhesion molecules and an association between altered brain metabolites and glycemic exposure suggest the presence of a vascularly mediated, progressive metabolic disturbance in the brain.

Adult↗
PubMed2003

Auditory discrimination after left-hemisphere stroke: a mismatch negativity follow-up study.

BACKGROUND AND PURPOSE: We sought to determine the recovery of cortical auditory discrimination in aphasic, left-hemisphere-stroke patients by using an electrophysiological response called mismatch negativity (MMN) and speech-comprehension tests. METHODS: MMN in 8 left-hemisphere stroke patients was recorded in response to duration and frequency changes in a repetitive, harmonically rich tone 4 and 10 days and again 3 and 6 months after their first unilateral stroke. Eight age-matched, healthy persons served as control subjects. RESULTS: At 4 days after stroke onset, patients' sound discrimination was impaired in their left hemisphere, as suggested by attenuated MMNs, especially to right-ear stimuli. At 3 months after stroke, however, MMN to the right-ear duration change had significantly increased and was of normal size. A significant change for the frequency MMN was found for left-ear stimuli between 3 and 6 months after stroke. During the follow-up period, progressive improvement in speech-comprehension tests was also observed. Furthermore, there was a significant correlation between the change in the duration MMN amplitude and the Boston Diagnostic Aphasia Examination speech-comprehension test from 10 days to 3 months after stroke. CONCLUSIONS: These results suggest that the MMN can be used as an index of the recovery of auditory discrimination.

Acoustic Stimulation↗
PubMed2003

Cerebral hemodynamics in asymptomatic and symptomatic patients with high-grade carotid stenosis undergoing carotid endarterectomy.

BACKGROUND AND PURPOSE: Asymptomatic patients with carotid stenosis benefit less from carotid endarterectomy (CEA) than symptomatic patients because the risk of embolic events is lower, but it is not known whether the hemodynamic effect of CEA is different between the groups. We evaluated hemodynamics of symptomatic and asymptomatic patient groups before and after CEA. METHODS: Forty-six independent patients with a unilateral high-grade carotid stenosis, 23 asymptomatic and 23 symptomatic, underwent dynamic susceptibility contrast MRI (DSC-MRI) and transcranial Doppler ultrasound (TCD) evaluation before CEA and 3 and 100 days afterward. Quantitative perfusion parameters were calculated separately in selected regions of white and gray matter and watershed regions in each hemisphere, and mean transit time (MTT) maps were assessed visually by 2 independent observers. Vasomotor reactivity was determined with breath-holding index and flow impedance with pulsatility index ipsilaterally. RESULTS: In contrast to the asymptomatic carotid stenosis group, symptomatic carotid stenosis patients had preoperatively increased MTT and lower cerebral blood flow values in the ipsilateral hemisphere, more in white matter and watershed regions than in gray matter. Visually detected perfusion deficits were associated with symptomatic status. The interhemispheric asymmetries were abolished by CEA. The improving trend over time was greater in the symptomatic carotid stenosis group and was best seen in MTT. On TCD, pulsatility index was lower in symptomatic carotid stenosis patients preoperatively, with no postoperative difference, whereas the breath-holding index improved only in the symptomatic carotid stenosis group after CEA. CONCLUSIONS: Patients with asymptomatic and symptomatic carotid stenosis differ significantly by means of DSC-MRI and TCD before and in response to CEA.

Aged↗
PubMed2003

Community-based thrombolytic therapy of acute ischemic stroke in Helsinki.

BACKGROUND AND PURPOSE: Thrombolysis with alteplase is used in acute ischemic stroke within 3 hours after symptom onset in many stroke centers, but experience remains limited in Europe. METHODS: Using eligibility and management criteria similar to those published by the American Heart Association, we treated 75 consecutive patients aged 21 to 83 years (mean age, 63.6 years; median Scandinavian Stroke Scale score, 32/58) with hemispheric infarction with alteplase in 1998-2001. Their neuroradiological findings (ischemic and hemorrhagic changes) and functional outcome at 3 months were evaluated. RESULTS: Sixty-one percent of the patients had recovered functional independence (Barthel Index 95 to 100) at the 3-month follow-up. On the modified Rankin Scale (mRS), 37% (28/75) of patients had no or minimal symptoms (mRS 0 to 1), while 17% (13/75) remained dependent (mRS 4 to 5) and 5% (4/75) died. Cerebral parenchymal hematomas occurred in 8% (6/75) and hemorrhagic transformation in 8% (6/75) of the patients. Low initial diastolic blood pressure and administration of intravenous antihypertensive medication were associated with unfavorable outcome (mRS 3 to 6). CONCLUSIONS: We conclude that our management protocol for thrombolytic therapy is safe. These rates of functional outcome, case fatality, and hemorrhagic cerebral events compare favorably with those of other published series of stroke thrombolysis with similar time windows and management guidelines. Associations between blood pressure and its treatment during thrombolysis with functional outcome deserve further analysis.

Academic Medical Centers↗
PubMed2002

Fetal hypoxia and structural brain abnormalities in schizophrenic patients, their siblings, and controls.

BACKGROUND: Cortical gray matter reductions and cerebrospinal fluid (CSF) increases are robust correlates of schizophrenia, but their relationships to obstetric and other etiologic risk factors remain to be established. METHODS: Structured diagnostic interviews, obstetric hospital records, and magnetic resonance imaging scans of the brain were obtained for 64 schizophrenic or schizoaffective patients (representative of all such probands in a Helsinki, Finland, birth cohort), along with 51 of their nonpsychotic full siblings and 54 demographically similar controls without family histories of psychosis. RESULTS: Fetal hypoxia predicted reduced gray matter and increased CSF bilaterally throughout the cortex in patients (gray matter effect sizes, -0.31 to -0.56; CSF effect sizes, 0.25 to 0.47) and siblings (gray matter effect sizes, 0.33 to 0.47; CSF effect sizes, 0.17 to 0.33), most strongly in the temporal lobe. Effect sizes were 2 to 3 times greater among cases born small for their gestational age. Hypoxia also correlated significantly with ventricular enlargement, but only among patients (effect size, 0.31). In contrast, fetal hypoxia was not related to white matter among patients and siblings, nor to any tissue type in any region among controls. The associations were independent of family membership, overall brain volume, age, sex, substance abuse, and prenatal infection. CONCLUSIONS: Fetal hypoxia is associated with greater structural brain abnormalities among schizophrenic patients and their nonschizophrenic siblings than among controls at low genetic risk for schizophrenia. This pattern of results points to a gene-environment interaction account of the disorder's neurodevelopmental pathogenesis.

Adult↗
PubMed2002

MRI findings in children with school problems who had been exposed prenatally to alcohol.

This study examined 17 children (nine males, eight females; mean age 13 years) with prenatal alcohol exposure of various durations. The aim of the study was to detect specific brain morphological alterations by means of MRI and to see if findings correlated with particular cognitive deficits. Of the 17 children, five had been exposed to heavy maternal consumption of alcohol (over 10 drinks/week) during the first trimester only; four had been exposed during the first and second trimester; and eight had been exposed throughout pregnancy. Five children had alcohol related neurobehavioural disorder, seven were diagnosed as having foetal alcohol effects and five were diagnosed as having foetal alcohol syndrome. Hypoplasia of the vermis was observed in 10 children and malformed posterior vermis in one additional child. Five children had hypoplastic cerebellar hemispheres. Hypoplasia of the corpus callosum was observed in two children. Small hippocampi were observed in three children and wide cortical sulci in six. No specific structural anomaly correlated with a particular neuropsychological deficit. In this study, deviations in the development of the vermis was the most sensitive morphological indicator of the effects of prenatal alcohol exposure. It was seen in every diagnostic group including children who had been exposed during only the first trimester of pregnancy.

Adolescent↗