Long-term prognostic value of quantitative myocardial perfusion in patients with chest pain and normal coronary arteries.

BACKGROUND: Patients with chest pain and no obstructive coronary artery disease have shown a high incidence of major adverse cardiovascular events (MACE). We evaluated the role of absolute myocardial perfusion quantification in predicting all-cause mortality and MACE during long-term follow-up in this group of patients. METHODS: We studied 79 patients who underwent Nitrogen-13 ammonia PET for quantification of global myocardial blood flow (MBF) and myocardial flow reserve (MFR) due to suspected impaired myocardial perfusion. Patients with coronary artery disease (i.e., > 30% stenosis in one or more coronary arteries) were excluded. We assessed all-cause mortality and MACE. MACE was defined as the composite incidence of death, myocardial infarction (MI), or hospitalization due to heart failure. RESULTS: Median follow-up was 8 (IQR: 3-14) years. Univariate Cox regression showed that only MFR (P = 0.01) was a predictor of all-cause mortality. Univariate Cox regression analysis showed that both MFR and Stress MBF were predictors of the composite endpoint of MACE (P < 0.001 and P = 0.01, respectively). CONCLUSION: Quantitative assessment of myocardial perfusion may predict all-cause mortality and MACE in patients with chest pain and normal coronary arteries in the long-term follow-up.

Perception of radiology reporting efficacy by neurologists in general and university hospitals.

AIM: To investigate how neurologists perceive the value of the radiology report and to analyse the relation with the neurologists own expertise in radiology and the level of subspecialisation of radiologists. MATERIALS AND METHODS: A web-based survey was distributed to neurologists. The level of subspecialisation was assessed by the percentage of fellowship-trained radiologists and the percentage of radiologists that were members of the Dutch Society of Neuroradiology. RESULTS: Most neurologists interpret all computed tomography (CT) and magnetic resonance imaging (MRI) studies themselves, and their self-confidence in making correct interpretations is high. Residents gave higher scores than neurologists for "Radiologist report answers the question" (p=0.039) and for "Radiologist reports give helpful advice" (p=0.001). Neurologists from university hospitals stated more frequently that the report answered their questions than neurologists from general hospitals (p=0.008). The general appreciation for radiology reports was higher for neurologists from university hospitals than from general hospitals (8.2 versus 7.2; p=0.003). Radiologists at university hospitals have a higher level of subspecialisation than those at general hospitals. CONCLUSION: Subspecialisation of radiologists leads to higher quality of radiology reporting as perceived by neurologists. Because of their expertise in radiology, neurologists are valuable sources of feedback for radiologists. Paying attention to the clinical questions and giving advice tailored to the needs of the referring physicians are opportunities to improve radiology reporting.

Clinical relevance of microhemorrhagic lesions in subacute mild traumatic brain injury.

Magnetic resonance imaging (MRI) is often performed in patients with persistent complaints after mild traumatic brain injury (mTBI). However, the clinical relevance of detected microhemorrhagic lesions is still unclear. In the current study, 54 patients with uncomplicated mTBI and 20 matched healthy controls were included. Post-traumatic complaints were measured at two weeks post-injury. Susceptibility weighted imaging and T2*-gradient echo imaging (at 3 Tesla) were performed at four weeks post-injury. Microhemorrhagic lesions (1-10 mm) were subdivided based on depth (superficial or deep) and anatomical location (frontal, temporoparietal and other regions). Twenty-eight per cent of patients with mTBI had ≥1 lesions compared to 0 % of the healthy controls. Lesions in patients with mTBI were predominantly located within the superficial frontal areas. Number, depth and anatomical location of lesions did not differ between patients with and without post-traumatic complaints. Within the group of patients with complaints, number of complaints was not correlated with number of lesions. In summary, microhemorrhages were found in one out of four patients with uncomplicated mTBI during follow-up at four weeks post-injury, but they were not related to early complaints.

The association between microhaemorrhages and post - traumatic functional outcome in the chronic phase after mild traumatic brain injury.

PURPOSE: In the chronic phase after mild traumatic brain injury (mTBI), microhaemorrhages are frequently detected on magnetic resonance imaging (MRI). It is however unclear whether microhaemorrhages are associated with functional outcome and which MRI sequence is most appropriate to address this association. We aimed to determine the association between microhaemorrhages and functional outcome in the chronic posttraumatic phase after injury with the most suitable MRI sequence to address this association. METHODS: One hundred twenty-seven patients classified with mTBI admitted to the outpatient clinic from 2008 to 2015 for persisting posttraumatic complaints were stratified according to the presence of MRI abnormalities (n = 63 (MRI+ group) and n = 64 without abnormalities (MRI- group)). For the detection of microhaemorrhages, susceptibility-weighted imaging (SWI) and T2* gradient recalled echo (T2*GRE) were used. The relation between the functional outcome (dichotomized Glasgow Outcome Scale Extended scores) and the number and localization of microhaemorrhages was analysed using binary logistic regression. RESULTS: SWI detected twice as many microhaemorrhages compared to T2*GRE: 341 vs. 179. Lesions were predominantly present in the frontal and temporal lobes. Unfavourable outcome was present in 67% of the MRI+ group with a significant association of total number of microhaemorrhages in the temporal cortical area on SWI (OR 0.43 (0.21-0.90) p = 0.02), with an explained variance of 44%. The number of microhaemorrhages was not correlated with the number of posttraumatic complaints. CONCLUSION: An unfavourable outcome in the chronic posttraumatic phase is associated with the presence and number of microhaemorrhages in the temporal cortical area. SWI is preferably used to detect these microhaemorrhages.

The presence of brain white matter lesions in relation to preeclampsia and migraine.

INTRODUCTION: Identifying female-specific risk markers for cerebrovascular disease is becoming increasingly important. Both migraine and preeclampsia have been associated with higher incidence of brain white matter lesions (WML) and stroke. We assessed the association between WML and migraine among formerly (pre)eclamptic women. METHODS: A total of 118 women (76 formerly (pre)eclamptic and 42 control women) were screened for migraine and WML presence. Independent effects of migraine and (pre)eclampsia on WML were assessed. RESULTS: Migraine prevalence did not differ between the (pre)eclamptic (26/76; 34%); and control group (10/42; 24%), p = 0.17. Age-adjusted regression analysis failed to show a significant independent effect of migraine (OR 1.14; 95% CI 0.47-2.76; p = 0.77) on WML presence, and showed a non-significant effect of (pre)eclampsia (OR 2.30; 95% CI 0.90-5.83; p = 0.08). CONCLUSION: Migraine prevalence was not found to be an independent risk factor for WML prevalence in formerly (pre)eclamptic women. Since this study had a small sample size, larger prospective studies are needed to examine female-specific risk factors for WML and its consequences.

Human Dermal Fibroblasts Demonstrate Positive Immunostaining for Neuron- and Glia- Specific Proteins.

In stem cell cultures from adult human tissue, undesirable contamination with fibroblasts is frequently present. The presence of fibroblasts obscures the actual number of stem cells and may result in extracellular matrix production after transplantation. Identification of fibroblasts is difficult because of the lack of specific fibroblast markers. In our laboratory, we isolate and expand neural-crest-derived stem cells from human hair follicle bulges and investigate their potential to differentiate into neural cells. To establish cellular identities, we perform immunohistochemistry with antibodies specific for glial and neuronal markers, and use fibroblasts as negative control. We frequently observe that human adult dermal fibroblasts also express some glial and neuronal markers. In this study, we have sought to determine whether our observations represent actual expression of these markers or result from cross-reactivity. Immunohistochemistry was performed on human adult dermal fibroblasts using acknowledged glial and neuronal antibodies followed by verification of the data using RT-qPCR. Human adult dermal fibroblasts showed expression of the glia-specific markers SOX9, glial fibrillary acidic protein and EGR2 (KROX20) as well as for the neuron-specific marker class III ß-tubulin, both at the protein and mRNA level. Furthermore, human adult dermal fibroblasts showed false-positive immunostaining for S100ß and GAP43 and to a lower extent for OCT6. Our results indicate that immunophenotyping as a tool to determine cellular identity is not as reliable as generally assumed, especially since human adult dermal fibroblasts may be mistaken for neural cells, indicating that the ultimate proof of glial or neuronal identity can only be provided by their functionality.

Hair follicle bulge cultures yield class III ß-tubulin-positive melanoglial cells.

Class III ß-tubulin (TUBB3)-positive cells from the hair follicle bulge are thought to be neuronal cells derived from a local neural crest stem cell. However, TUBB3 has recently been shown to be expressed in the melanocytic lineage. To evaluate the neural-crest-associated immunophenotype of TUBB3-positive cells from hair follicle bulge explants, we dissected hair follicle bulges out from mouse whisker pads and cultured for 1 month and assessed outgrowing cells by means of immunocytochemistry using the biomarkers TUBB3, nestin, NGFR, SOX9, TYRP1 and laminin. Large amounts of TUBB3-positive cells could be cultured that co-expressed nestin, NGFR, SOX9 and, to a lesser degree, TYRP1, matching a melanoglial phenotype. In addition, a small population of TUBB3-negative but laminin-positive cells was found, which presumably are of glial origin. It can be concluded that cells of melanoglial origin can easily be obtained from hair follicle bulge explants. These cells may be of use in experimental animal or human disease and wound healing models. Notably, the TUBB3-positive cells are of melanoglial rather than neuronal origin.

Three phenotypes of adult-onset asthma.

RATIONALE: Adult-onset asthma differs from childhood-onset asthma in many respects. It is more heterogeneous, often severe and frequently associated with loss of lung function. To identify underlying mechanisms of adult-onset asthma and to capture predictors of disease progression, detailed characterization and phenotyping is necessary. OBJECTIVES: To characterize adult-onset asthma and identify subphenotypes of adult-onset asthma. METHODS: A cohort of 200 patients with adult-onset (>18 year) asthma (age 54 (26-75) year) was recruited from one academic and three nonacademic pulmonary outpatient clinics in Amsterdam, the Netherlands. These patients were fully characterized with respect to clinical, functional and inflammatory markers. After data reduction, K-means nonhierarchical cluster analysis was performed to identify clusters of adult-onset asthma. MEASUREMENTS AND MAIN RESULTS: Patients with adult-onset asthma were predominately female (61%) and nonatopic (55%). Within this group of patients were identified three clusters of adult-onset asthma. Cluster 1 (n = 69) consisted of patients with severe eosinophilic inflammation-predominant asthma and persistent airflow limitation despite high-intensity anti-inflammatory treatment, with relatively low symptom scores. The second cluster was characterized by obese women with frequent symptoms, high healthcare utilization and low sputum eosinophils. The third cluster consisted of patients with mild-to-moderate, well-controlled asthma with normal lung function and low inflammatory markers. Repeatability accuracy was 98.2%. CONCLUSIONS: Amongst patients with adult-onset asthma, three subphenotypes can be identified with distinct clinical and inflammatory characteristics. These subphenotypes help to understand the underlying pathobiology and provide clinicians with directions for personalized management.

Long-term cerebral imaging after pre-eclampsia.

OBJECTIVE: Formerly eclamptic women demonstrate cerebral white matter lesions (WMLs) several years following the index pregnancy. The pathophysiology is unclear and may be related to the predisposition for cerebrovascular/cardiovascular disease in such women and/or the occurrence of posterior reversible encephalopathy syndrome whilst pregnant. The aim of this study was to assess the presence and severity of WMLs and their relationship with the severity of the neurological symptoms during the index pregnancy and several current cardiovascular risk factors in formerly pre-eclamptic women. DESIGN: This was a retrospective cohort study. SETTING: The Neuroimaging Centre at the School for Behavioural and Cognitive Neurosciences, Groningen, the Netherlands. POPULATION: Seventy-three formerly pre-eclamptic women were matched for age (37 ± 6 years) and elapsed time since index pregnancy (5.1 ± 3.7 years) with parous control women. METHODS: Cerebral magnetic resonance imaging scans were performed on cases and controls. Scans were rated by a neuroradiologist blind to the patient category. MAIN OUTCOME MEASURES: The presence and severity of cerebral WMLs. RESULTS: Formerly pre-eclamptic women had WMLs significantly more often (37%) and more severely (mean, 0.11; median, 0.00; range, 0-2.34 ml) than controls (21%, P = 0.04; mean, 0.015; median, 0.00; range, 0-0.13 ml; P = 0.02). Current hypertension and a history of early-onset pre-eclampsia (<37 weeks) were independently associated with the presence of WMLs (ß = 1.34, P = 0.02 and ß = 1.73, P = 0.01, respectively). CONCLUSIONS: Our findings indicate that pre-eclampsia might be a risk marker for early cerebrovascular damage. The predisposition of formerly pre-eclamptic women to later cardiovascular and cerebrovascular disease may be an important factor for the development of cerebral WMLs. Whether a history of posterior reversible encephalopathy syndrome may be an additive risk factor for the development of these lesions remains unknown.

T2 lesions and rate of progression of disability in multiple sclerosis.

BACKGROUND AND PURPOSE: To assess the predictive value of T2 lesions on the rate of progression of disability in multiple sclerosis (MS). METHODS: We reanalyzed T2 lesion number and load on brain MRI scans, performed before 1997, of 186 MS patients, who were clinically followed. There were 90 patients with progressive MS (35 secondary progressive and 55 primary progressive), and 96 with relapsing remitting MS. The rate of progression of disability was measured by time to sustained progression of disability (defined as an increase in ≥ 1 point when the Expanded Disability Status Scale (EDSS) was 5.5 or less and an increase in EDSS of ≥ 0.5 point when the EDSS was 6.0 or higher), and by the Multiple Sclerosis Severity Score (MSSS). RESULTS: During follow-up (median 15 years, IQR 12-17 years), 94% of the patients with progressive MS and 50% of the patients with relapsing remitting MS had progression of disability. Higher T2 lesion number and load were modestly associated with a higher rate of disease progression on the MSSS and a shorter time to progression of disability in relapsing remitting MS, but not in progressive MS. CONCLUSIONS: Our findings indicate that the amount of T2 lesions has a small predictive value for progression of disability in relapsing remitting MS, but has no influence on the rate of progression in progressive MS.

Effects of aging on inner ear morphology in dogs in relation to brainstem responses to toneburst auditory stimuli.

BACKGROUND: Age-related hearing loss (ARHL) is the most common form of hearing loss in humans and is increasingly recognized in dogs. HYPOTHESIS: Cochlear lesions in dogs with ARHL are similar to those in humans and the severity of the histological changes is reflected in tone audiograms. ANIMALS: Ten geriatric dogs (mean age: 12.7 years) and three 9-month-old dogs serving as controls for histological analysis. METHODS: Observational study. Auditory thresholds were determined by recording brainstem responses (BERA) to toneburst auditory stimuli (1, 2, 4, 8, 12, 16, 24, and 32 kHz). After euthanasia and perfusion fixation, the temporal bones were harvested and processed for histological examination of the cochleas. The numbers of outer hair cells (OHCs) and inner hair cells (IHCs) were counted and the spiral ganglion cell (SGC) packing density and stria vascularis cross-sectional area (SVCA) were determined. RESULTS: A combination of cochlear lesions was found in all geriatric dogs. There were significant reductions (P .001) in OHC (42%, 95% confidence interval [CI]; 24-64%) and IHC counts (21%, 95% CI; 62-90%) and SGC packing densities (323, 95% CI; 216-290) in the basal turn, SVCA was smaller in all turns. The greatest reduction in auditory sensitivity was at 8-32 kHz. CONCLUSIONS AND CLINICAL IMPORTANCE: ARHL in this specific population of geriatric dogs was comparable histologically to the mixed type of ARHL in humans. The predominance of histological changes in the basal cochlear turn was consistent with the large threshold shifts observed in the middle- to high-frequency region.

MR spectroscopy and diffusion tensor imaging of the brain in Sjögren-Larsson syndrome.

Diffusion tensor imaging (DTI) is reported for the first time in a patient with Sjögren-Larsson syndrome, an autosomal recessive neurocutaneous disorder. Magnetic resonance spectroscopy (MRS) revealed normal levels of choline, creatine and N-acetyl aspartate (NAA) and the characteristic lipid signals in the white matter brain tissue. Conventional MRI showed increased signal intensity around the lateral ventricles indicating abnormal myelination. DTI revealed normal apparent diffusion coefficient (ADC) values, but reduced fractional anisotropy (FA) in the white matter. After co-registration of the parameters obtained with DTI with the results of MRS (36 voxels), significant correlations were obtained of lipid content with FA (r=0.81), ADC (r=-0.62), choline (r=0.51), and NAA (r=0.44) (P<0.01, all). These results suggest that in Sjögren-Larsson syndrome, the white matter lipid signals originate from the neurons, with NAA and choline reflecting neuron density and myelination. The comparatively high FA/low ADC values in these lipid-rich locations, indicate a loss of diffusion in directions perpendicular to the fibers. The overall loss of FA in the white matter may reflect a loss of brain tissue water content in SLS patients compared with controls and precede the formation of atrophy.

Relationship between the extent of T2 lesions and the onset of secondary progression in multiple sclerosis.

Patients with relapsing-remitting multiple sclerosis (MS) are at risk of converting to a secondary progressive disease course. To assess the relationship between brain magnetic resonance imaging (MRI) findings and onset of secondary progression, we reanalyzed the initial brain MRI scans of 90 relapsing-remitting MS patients, who were clinically followed up for at least 10 years (median 14 years) after their scan, for the number and volume of T2 lesions, and for two measures of brain atrophy (bicaudate ratio and third ventricle width). The relationship to development of secondary progression was studied with Cox regression models and Kaplan-Meier survival analyses. At the end of follow-up, 36 patients had become progressive. The presence of more than 10 T2 lesions more than doubled the risk of becoming secondary progressive (hazards ratio 2.36; 95% CI 1.19-4.66). When at least one of the 10 lesions was confluent the risk increased to 3.51 (1.64-7.50). The hazards ratio for an estimated T2 lesion load of more than 800 mm(3) was 2.11 (1.07-4.16). Linear brain atrophy measures were not predictive. Our data show a relationship between the extent of brain T2 lesions and the onset of secondary progression in MS.

Reduced expression of sialoglycoconjugates in the outer hair cell glycocalyx after systemic aminoglycoside administration.

In this study we investigated the effect of systemic aminoglycoside administration on the expression of sialoglycoconjugates in the outer hair cell (OHC) glycocalyx of the adult guinea pig. Sialoglycoconjugates were visualized by means of ultrastructural lectin cytochemistry, using Limax flavus agglutinin (LFA) and wheat germ agglutinin (WGA) as probes. Labelling densities were determined for the apical membranes (including the stereocilia and stereociliary cross-links) and basolateral membranes of OHCs in the respective (basal, middle and apical) cochlear turns from animals that had been treated with gentamicin or neomycin for 5 or 15 consecutive days. Our results indicate that: (1) sialoglycoconjugate expression in the OHC glycocalyx demonstrates an intracochlear gradient decreasing towards the apical turn; (2) OHCs demonstrate a polarity in sialoglycoconjugate expression, in that the basolateral membranes contain more sialoglycoconjugates per surface area than the apical membranes; (3) aminoglycoside administration results in reduced expression of sialoglycoconjugates in the OHC glycocalyx; in this respect, basal-turn OHCs are more susceptible than those in the middle and apical turns; (4) reduction in sialoglycoconjugate expression after aminoglycoside administration is more prominent in the basolateral membranes; and (5) the difference in ototoxic potencies between gentamicin and neomycin is not reflected at the level of sialoglycoconjugate expression. The present data support our earlier hypothesis that aminoglycosides, already at an early phase of intoxication, interfere with the function of the endoplasmic reticulum and/or the Golgi apparatus, implying that these organelles play a crucial role in the initial phase of aminoglycoside-induced OHC degeneration.

Arterial oxygen saturation, COPD, and cerebral small vessel disease.

OBJECTIVE: To study whether lower arterial oxygen saturation (SaO(2)) and chronic obstructive pulmonary disease (COPD) are associated with cerebral white matter lesions and lacunar infarcts. METHODS: We measured SaO(2) twice with a pulse oximeter, assessed the presence of COPD, and performed MRI in 1077 non-demented people from a general population (aged 60-90 years). We rated periventricular white matter lesions (on a scale of 0-9) and approximated a total subcortical white matter lesion volume (range 0-29.5 ml). All analyses were adjusted for age and sex and additionally for hypertension, diabetes, body mass index, pack years smoked, cholesterol, haemoglobin, myocardial infarction, and left ventricular hypertrophy. RESULTS: Lower SaO(2) was independent of potential confounders associated with more severe periventricular white matter lesions (score increased by 0.12 per 1% decrease in SaO(2) (95% confidence interval 0.01 to 0.23)). Participants with COPD had more severe periventricular white matter lesions than those without (adjusted mean difference in score 0.70 (95% confidence interval 0.23 to 1.16)). Lower SaO(2) and COPD were not associated with subcortical white matter lesions or lacunar infarcts. CONCLUSION: Lower SaO(2) and COPD are associated with more severe periventricular white matter lesions.

Hypertension and cerebral white matter lesions in a prospective cohort study.

White matter lesions are frequently found on cerebral MRI scans of elderly people and are thought to be important in the pathogenesis of dementia. Hyper tension has been associated with the presence of white matter lesions but this has been investigated almost exclusively in cross-sectional studies. We studied prospectively the association of these lesions with the duration and treatment of hypertension. We randomly sampled 1077 subjects aged between 60 and 90 years from two prospective population-based studies. One-half of the study subjects had their blood pressure measured between 1975 and 1978 and the other half between 1990 and 1993. All subjects underwent 1.5 T MRI scanning; white matter lesions in the subcortical and periventricular regions were rated separately. Subjects with hypertension had increased rates of both types of white matter lesion. Duration of hypertension was associated with both periventricular and subcortical white matter lesions. This relationship was influenced strongly by age. For participants with >20 years of hypertension and aged between 60 and 70 years at the time of follow-up, the relative risks for subcortical and periventricular white matter lesions were 24.3 [95% confidence interval (CI) 5.1-114.8] and 15.8 (95% CI 3.4-73.5), respectively, compared with normotensive subjects. Subjects with successfully treated hypertension had only moderately increased rates of subcortical white matter lesions and periventricular white matter lesions (relative risk 3.3, 95% CI 1.3-8.4 and 2.6, 95% CI 1.0-6.8, respectively) compared with normotensive subjects. For poorly controlled hypertensives, these relative risks were 8.4 (95% CI 3.1-22.6) and 5.8 (95% CI 2.1-16.0), respectively. In conclusion, we found a relationship between long-standing hypertension and the presence of white matter lesions. Our findings are consistent with the view that effective treatment may reduce the rates of both types of white matter lesion. Adequate treatment of hypertension may therefore prevent white matter lesions and the associated cognitive decline.

[Cerebral white matter lesions in the elderly: vascular risk factors and cognitive consequences]. / Wittestofafwijkingen in de hersenen bij ouderen: vasculaire risicofactoren en mentale gevolgen.

With the advent of sensitive brain imaging techniques, white matter lesions are commonly observed in healthy as well as in demented elderly people. Primarily vascular risk factors have been related to the presence of white matter lesions, such as hypertension, atherosclerosis and atrial fibrillation. Subcortical white matter lesions are mainly associated with depression in the elderly, while periventricular lesions are clearly associated with cognitive dysfunction. Current evidence on the relation between vascular risk factors, white matter lesions and cognition is based on cross-sectional studies. Prospective studies are needed to confirm causality and to study the efficacy of treatment of vascular risk factors.

Human brain chemical shift imaging at age 60 to 90: analysis of the causes of the observed sex differences in brain metabolites.

RATIONALE AND OBJECTIVES: To assess whether differences in cerebral atrophy and white matter lesions or in the presence of lactate and lipid signals can explain the observed differences in brain choline, creatine, and N-acetylaspartate levels between healthy elderly women and men. METHODS: In addition to standard magnetic resonance imaging of the brain, an 8 x 8 x 2-cm3 supraventricular transverse brain volume parallel to the canthomeatal line was examined by magnetic resonance spectroscopy (automated 1H chemical shift imaging) in 540 healthy elderly persons. RESULTS: At P = 0.01, 0.001, and 0.0001, choline differed between women and men in 14, 9, and 5 of 36 voxels, respectively. On correction for cerebral atrophy (more frequent in men than in women), white matter lesions (more frequent in women), and lactate and lipid (more frequent in women), the differences in choline were reduced to 13, 6, and 3. Sex differences for creatine and N-acetylaspartate were similar but less numerous after correction. CONCLUSIONS: Elderly women and men in the general population show differences in the levels of creatine, N-acetylaspartate, and especially choline in portions of the brain. The sex-related differences in brain metabolite levels cannot be explained by differences in cerebral atrophy or other aging-related phenomena (white matter lesions, lactate, lipid).