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At least 775 records · Page 43Linked to original sources
PubMed2002

Pattern and significance of white matter abnormalities in myotonic dystrophy type 1: an MRI study.

We reviewed the brain MRI of 66 patients with the adult form of myotonic dystrophy type 1 (DM1) to evaluate the extent and significance of white matter involvement and to look for a pattern of MRI abnormalities suggestive of DM1. White matter lesions (WMLs) and large Virchow Robin spaces (VRSs) were rated by semiquantitative methods and the signal intensity of white matter superior and posterior to the trigones (WMPST) by reference to standard images. Disease duration was correlated positively with WML and negatively with VRS scores. Patients were divided into four groups according to increasing severity of WMPST involvement: group A with mild WMPST hyperintensity, group B with large VRSs and mild or moderate WMPST hyperintensity, group C with moderate WMPST hyperintensity or mild WMPST hyperintensity with small WMLs, group D with severe WMPST hyperintensity or moderate WMPST hyperintensity with small WMLs. Disease duration, muscular impairment, lobar WMLs and brain atrophy significantly increased from groups A and B (not significantly different) to C and from C to D, while convexity VRSs significantly decreased from group B to C and from C to D. Lobar white matter involvement in DM1 seems progressive during the disease and may be characterized initially by large VRSs or mild WMPST hyperintensity, then by small WMLs or moderate WMPST hyperintensity, and finally by more extensive and confluent WMLs or diffuse white matter hyperintensity and by brain atrophy.

Adult↗
PubMedDate not supplied

Apoptosis and white matter injury in preterm infants.

White matter injury in premature infants with or without intraventricular hemorrhage (IVH) remains an important cause of neonatal mortality and neurologic morbidity. The contribution of apoptosis to the cellular death in white matter injury in the preterm infant is unclear. The objective of this study was to determine whether apoptosis contributes to the cellular death in premature infants with cranial ultrasound (US) evidence of IVH and asymmetric periventricular echogenicity (PVE). Brain tissue incorporating frontoparietal white matter was obtained from 21 infants: 6 infants with severe IVH and asymmetric PVE (grade 1V IVH) on US (group 1); 9 infants with minimal IVH or normal US who died within 21 days (group II); and 6 infants with minimal IVH or normal US who died later (group III). The presence of DNA fragmentation, typical of apoptosis, was determined using a terminal deoxytransferase-mediated dUTD nick-end labeling (TUNEL) assay. The TUNEL index for group I infants was significantly greater, i.e., 2.75 +/- 1.94% versus 0.84 +/- 0.70% for group II and 0.42 +/- 0.22 for group III infants (P = 0.004). Most cells showing reactivity had morphologic characteristics consistent with astrocytes and oligodendroglia. The number of white matter cells showing morphologic changes consistent with apoptosis, such as nuclear blebs and karyorrhexis, was also quantitated and was significantly more numerous in group I than in group II infants, i.e., 0.51 +/- 0.64% versus 0.02 +/- 0.05% (P = 0.0005), and group III infants, i.e., 0.10 +/- 0.18% (P = 0.03). These findings implicate apoptosis as a contributing mechanism for the cellular death in infants with IVH and asymmetric PVE. Strategies aimed at preventing the white matter injury will need to incorporate methods of inhibiting the ongoing process of apoptosis.

Apoptosis↗
PubMed1999

Infant cerebellar gray and white matter fatty acids in relation to age and diet.

There is little evidence as to the fatty acid composition of the cerebellum in infancy and it remains uncertain whether milk diet can influence its composition. We therefore examined cerebellar gray and white matter of infants less than 6 month old who had died unexpectedly. The fatty acid content of 33 gray and 21 white matter specimens from infants born at term and 6 gray and 5 white matter specimens from preterm infants was assessed by gas chromatographic/mass spectrometric analysis. Infants were grouped according to whether they had received human or manufactured formula milk. Whereas cerebellar cortex docosahexaenoic acid (DHA, 22:6n-3) concentrations were significantly lower (P<0.01) in the formula-fed than breast-fed infants, no differences existed between the term (n = 10) and preterm (n = 5) Synthetic Milk Adapted [corrected] (SMA) formula-fed infants. Cerebellar white matter DHA concentrations were similarly lower (P<0.01) in the SMA formula-fed infants (n = 8) than in an age-matched breast-fed group. Low concentrations of cerebellar white matter lignoceric (24:0) and nervonic acid (24:1n-9) in two 7-wk-old preterm infants appeared to correlate with postgestational rather than chronological age. Dietary long-chain polyunsaturated fatty acids, particularly DHA, are probably essential for normal development of the infant cerebellum.

Aging↗
PubMed1980

Gray and white matter brain-blood transfer constants by steady-state tissue clearance in cat.

Capillary transfer constants for gray matter have been measured by others from steady-state tissue clearance during ventriculocisternal perfusion. Similar studies in white matter, however, are complicated by the bulk flow of interstitial fluid (ISF). Recently we determined the velocity of bulk flow of ISF under normal conditions. We now report capillary transfer constants in gray and white matter by steady-state tissue clearance in the cat. Adults cats underwent a 2, 3, or 4 h ventriculocisternal perfusion with artificial cerebrospinal fluid containing [3H]sucrose and either [14C]urea or [14C]ethylene glycol. Diffusion coefficients and velocity of bulk flow were determined from tissue concentrations of the extracellular marker, sucrose. Steady-state tissue concentrations of urea and ethylene glycol were used to calculate transfer of those compounds from the brain to the blood. Urea reached steady-state by the third hour; capillary transfer constants were similar in gray and white matter. Ethylene glycol reached steady-state by the second hour; however, capillary transfer was more rapid in the gray matter than in white.

Animals↗
PubMed1988

Testosterone 5 alpha-reductase activity in the rat brain is highly concentrated in white matter structures and in purified myelin sheaths of axons.

Previous results obtained in this laboratory indicate that in the rat brain the 5 alpha-reductase, the enzymatic activity involved in metabolizing testosterone into 5 alpha-androstan-17 beta-ol-3-one (dihydrotestosterone), is particularly concentrated in the white matter. In the present experiments, this enzymatic activity was studied in the following white matter structures, which were microdissected using the punch technique of Palkovits: anterior commissure (CA), fornix (FX), habenulo-interpeduncular tract (HP), corpus callosum (CC), stria medullaris (SM), optic chiasm (CO), fimbria of the hippocampus (FI), cerebral peduncle (PC), pontine fibers (FP), cerebellar medulla (CMD) and corticospinal tract (TCS). Moreover brain myelin was isolated and purified by sucrose density gradient ultracentrifugation. The results obtained confirm that, in the rat brain, the enzymes involved in testosterone 5 alpha-reduction are preferentially localized in the white matter. However, clearcut differences in the metabolic activity exist between the different structures examined so far. DHT formation increases rostro-caudally, so that the highest activity has been recorded in the white matter structures punched at the level of pons (FP), medulla oblungata (TCS) and cerebellum (CMD). The high metabolic activity associated with the white matter structures appears to be linked to the presence of myelin, since the specific activity of the enzyme is particularly elevated in purified preparations of myelin sheaths.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1978

Differences in the time course of regional cerebral hemo-dynamics of gray and white matter during experimental hypertension.

Investigations concerned with the pathogenesis of hypertensive encephalopathy have reported two opposing changes in cerebral hemodynamics during induced hypertension: (1) vasospasm or vasoconstriction of the leptomeningeal arteries and (2) increase of cerebral blood flow which has been termed "breakthrough" of the cerebral autoregulation. To resolve this apparent conflict, continuous measurements of focal cerebral flow and oxygen availability were made in 17 baboons by the use of implanted platinum electrodes placed in both gray and white matter during induced hypertension. Autoregulation was initially well maintained in gray matter followed by "breakthrough" but the autoregulatory response was poorly maintained in the cerebral white matter. The vasoconstriction of the leptomeningeal arteries reported in earlier investigations from observations made through a skull window appears to be due to a marked autoregulatory response to hypertension rather than vasospasm. The autoregulatory response appears to be efficient in gray matter but relatively deficient in white matter.

Acute Disease↗
PubMed1979

A histological, histochemical and biochemical study of the macroscopically normal white matter in multiple sclerosis.

In a combined histological, biochemical and histochemical study of the macroscopically normal white matter in multipe sclerosis 72% of samples were histologically abnormal. The significance of this fact in the interpretation of previous biochemical studies and in the design of future studies is discussed. The present study showed a significant elevation of the lysosomal enzyme beta-glucosaminidase in the microscopically normal white matter in MS as compared with controls. Studies on lysosomes separated from microscopically normal or mild to moderately gliosed white matter in multiple sclerosis showed an increase in lysosomal fragility. Histochemical study of the microscopically normal white matter in multiple sclerosis revealed an increase in the number of acid phosphate-containing cells as compared with normal and neurological control material. The significance of these findings is discussed and it is suggested that irrespective of the primary or secondary nature of these abnormalities, the white matter may be rendered more susceptible to the pathogenetic process in this disease.

Acetylglucosaminidase↗
PubMed1995

Reactivity of normal T-cell lines to MBP isolated from normal and multiple sclerosis white matter.

T-cell reactivity to human myelin basic protein (MBP) has been extensively studied using T-cell lines and clones generated from both peripheral blood and cerebrospinal fluid, from normal controls and multiple sclerosis (MS) patients. These studies have largely utilized myelin basic protein isolated from control human adult white matter. In our study, we used MBP reactive T-cell lines as a probe to investigate antigenic differences in a series of MBP preparations isolated from either control human white matter or white matter from the central nervous system (CNS) of MS patients. Autologous peripheral blood derived mononuclear cells were used as antigen presenting cells (APC). Although the majority of T-cells were found to react equally well with all preparations of MBP isolated from both control and MS white matter, we were also able to identify T-cell lines which reacted well with all preparations of MBP isolated from controls but failed to react with MBP isolated from MS white matter. These differences were unlikely to reflect differences in degradation products or excess peptides present in the MS brain since SDS-PAGE and HPLC did not show any difference in the MS samples compared to the controls, and the concentration response curves for a human T-cell clone specific for the 84-102 region of MBP were similar for all the MBP preparations. We did not detect differences in amino acid content amongst MBP preparations although single amino acid substitutions cannot be ruled out. These results raise the possibility that MBP isolated from MS brain may differ in charge microheterogeneity which would affect antigenic determinants.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Frontal lobe degeneration of non-Alzheimer type. IV. White matter changes.

The cerebral white matter in 16 cases of frontal lobe non-Alzheimer degeneration with dementia (FLD), four cases of Pick's disease and five age-matched controls was studied microscopically. All cases of dementia had white matter alterations, consisting of gliosis and loss of myelin, with a regional spread of changes that roughly corresponded with that of the cortical degeneration. The white matter changes were less severe than the cortical alterations, although the relative degree of severity between grey and white matter pathology varied from case to case. The white matter changes were in some respects similar in FLD and Pick's disease. They differed from those of other organic dementias. In FLD, they seem to be part of the histopathologic picture and to be secondary to the cortical degeneration.

Aged↗
PubMed1986

Multiple biochemical deficits in both gray and white matter of Alzheimer brains.

A biochemical investigation of 21 brains from patients with dementia of Alzheimer type (AD/SDAT) and 22 brains from controls was made. In the normal brains 5-hydroxytryptamine (5-HT), noradrenaline (NA) and dopamine (DA) were reduced with age while their metabolites were not reduced. In the brains from the Alzheimer patients the examination of gray matter (caudate nucleus and hippocampus) showed a significant reduced activity of choline-acetyl transferase (CAT) and a reduction of acetylcholinesterase (AChE) that bordered significance in the hippocampus. In the brains from the Alzheimer patients a disturbance was found in the 5-HT system in the form of reduced levels of 5-HT and 5-hydroxyindolacetic acid (5-HIAA). The catecholamine systems were also disturbed but to a less extent. In the 5-HT and DA systems the active amines as well as the metabolites were reduced in the brains from patients with AD/SDAT indicating not only a possible neuronal loss but also an incapacity of the remaining neurons to compensate for the loss by an increased turnover. The lipid content was slightly reduced in gray matter of the demented brains. In white matter there was a more severe reduction of the lipids and in this tissue also the cerebrosides and sulfatides were reduced. It is concluded that in brains from patients with AD/SDAT there are multiple biochemical deficits in gray as well as in white matter. The changes in white matter may be of pathogenetic importance in subgroups of AD/SDAT.

Age Factors↗
PubMed1984

Localization and organization of geniculocortical and corticofugal fiber tracts within the subcortical white matter.

Reciprocal connections are formed between the dorsal lateral geniculate nucleus and the striate cortex in the mammalian visual system. The question of whether fibers of these corticopetal and corticofugal pathways are segregated or intermingled within the white matter is still open. In order to examine the organization of these fiber tracts within the white matter, we have used orthograde axonal transport of radiolabelled proteins and neuronal degeneration following kainic acid lesions in the geniculocortical and corticofugal pathways of the rat. Within the white matter the two pathways reside in different layers and are segregated from one another over a significant portion of their course, geniculocortical fibers lying in the external sagittal stratum and corticofugal fibers lying in the internal sagittal stratum of the white matter. In addition, the corticofugal pathways projecting to subcortical structures appear fasciculated in both the transport and the degeneration studies suggesting that axons of cortical output neurons are organized into fiber bundles. The separation of fibers within the white matter may be of potential use for selectively stimulating afferent and efferent pathways in electrophysiological studies in situ and in cortical slice preparations. In addition, the corticofugal fiber bundles may play an important role in guiding axons therein to appropriate targets during axonogeneis and may carry the output of columnar units within visual cortex.

Animals↗
PubMed1990

White matter damage in preterm newborns--an epidemiologic perspective.

Prior to 1980, white matter abnormalities of the preterm newborn were known exclusively as pathological entities, but now cranial ultrasonography can image white matter abnormalities in life. Ultrasonographic white matter echodensities and echolucencies in low birthweight babies predict later handicap (especially cerebral palsy) more accurately than any other antecedent. With the increased availability of high resolution cranial ultrasonography and the improved skill in obtaining and reading cranial ultrasonograms, rapid gains can be expected in our understanding of white matter disorders. These advances are likely to be made in the diagnosis and classification of white matter disorders and in their epidemiologic and prognostic features, topics explored in this review.

Brain↗
PubMed1986

Detection of heterotopic gray matter in children by magnetic resonance imaging.

Heterotopic gray matter results from abnormal brain development and is a recognized focus of seizures. It may be associated with mental retardation and/or severe malformations of the brain. Three patients with heterotopia of gray matter were identified by magnetic resonance imaging (MRI). CT failed to detect the heterotopic gray matter in each case. One child was referred for removal of a neoplasm based on CT studies until MRI demonstrated the developmental nature of his condition. One infant had severely dysplastic left cerebral hemisphere associated with heterotopic gray matter and the syndrome of Hypomelanosis of Ito. All three children suffered from seizures and/or mental retardation. MRI provided important information in the management of each case and appears to be the imaging method of choice in evaluating children with seizures or retardation for heterotopic gray matter in the brain.

Brain Neoplasms↗
PubMed2006

Cerebral white matter degeneration in frontotemporal dementia detected by diffusion-weighted magnetic resonance imaging.

RATIONALE AND OBJECTIVE: Brain tissue damage in frontotemporal dementia (FTD) has never been systematically studied using diffusion-weighted imaging (DWI). We studied FTD patients using DWI to determine whether microstructural changes in white matter can be detected in vivo. MATERIALS AND METHODS: Thirteen FTD patients and 15 aged healthy subjects were studied. Mean diffusivity (MD) abnormalities in 28 white matter regions were visually evaluated. In addition, MD values in 10 white matter regions relative to that in the ipsilateral postcentral gyrus were measured. The results were compared between healthy subjects and FTD patients. RESULTS: The visual rating resulted in a significant MD elevation in FTD patients in the bilateral high superior frontal gyri, right orbitofrontal gyrus, bilateral anterior temporal lobes, and left middle temporal lobe (P < .01, respectively). Relative MD comparison revealed a significant MD elevation in FTD patients in the bilateral high superior frontal gyri, bilateral orbitofrontal gyri, and bilateral anterior temporal lobes (P < .05 after Bonferroni correction, respectively). CONCLUSION: Our results demonstrated white matter MD abnormalities in FTD patients. It was suggested that the observed white matter MD abnormalities are secondary to damage in the overlying cortex.

Aged↗
PubMed2005

White matter density in patients with schizophrenia, bipolar disorder and their unaffected relatives.

BACKGROUND: This study sought to assess white matter density in patients and relatives with histories of bipolar disorder and/or schizophrenia. METHODS: Subjects included those with schizophrenia from families affected by schizophrenia alone, those with bipolar disorder from families affected by bipolar disorder alone and those with bipolar disorder from families affected by both bipolar disorder and schizophrenia. Unaffected relatives of the three patient groups were also recruited. Subjects underwent an MRI brain scan which was analyzed using a white-matter optimized technique. RESULTS: Subjects with schizophrenia and bipolar disorder showed reduced white matter density in the anterior limb of the internal capsule which was not found in unaffected relatives. Reductions were found in frontal subgyral white matter density in affected subjects with a family history of schizophrenia only. CONCLUSIONS: Abnormal anterior internal capsule white matter may provide a structural substrate for both disorders.

Adult↗
PubMed2005

Regional gray matter abnormalities in obsessive-compulsive disorder: a voxel-based morphometry study.

BACKGROUND: Several structural magnetic resonance imaging (MRI) studies have investigated the presence of brain abnormalities in obsessive-compulsive disorder (OCD) but have not produced consistent findings. This might be partly related to their use of a regions-of-interest approach. We assessed gray matter volumes in 19 OCD subjects and 15 healthy volunteers, using voxel-based morphometry (VBM). METHODS: Images were acquired with a 1.5-T MRI scanner, spatially normalized, and segmented with optimized VBM. Statistical comparisons were performed with the general linear model. RESULTS: Significant findings were detected in regions predicted a priori to be implicated in OCD, including increased gray matter in OCD subjects relative to control subjects in posterior orbitofrontal and parahippocampal regions; decreased gray matter in OCD patients in the left anterior cingulate cortex; and inverse correlations between obsessive-compulsive symptom severity and gray matter in the medial thalamus (p < .001, uncorrected for multiple comparisons). Also, an unpredicted site of gray matter reduction in OCD patients in the right parietal associative cortex approached significance (p = .052, corrected for multiple comparisons). CONCLUSIONS: Our findings are consistent with previous studies implicating dysfunction of orbitofrontal, cingulate, thalamic, and temporolimbic regions in OCD and suggest that the involvement of the parietal cortex in the pathophysiology of OCD warrants further investigation.

Adult↗
PubMed2005

Reduced anterior and posterior cingulate gray matter in borderline personality disorder.

BACKGROUND: Structural abnormalities in prefrontal and cingulate gyrus regions-important in affective processing, impulse control and cognition may contribute to the psychopathology of borderline personality disorder (BPD). Previous MRI studies examining volume have reported that compared with healthy controls, BPD patients have decreases in right anterior cingulate, no differences in dorsolateral prefrontal cortex, and mixed findings for prefrontal cortex. We extended this investigation by examining gray and white matter volume of frontal and cingulate gyrus Brodmann areas (BAs) in a large group of patients and healthy controls. METHODS: MRI scans were acquired in 50 BPD patients (n = 13 with comorbid diagnosis of BPD and Schizotypal Personality Disorder (SPD) and n = 37 without SPD) and 50 healthy controls, and gray/white matter volume in cingulate gyrus and frontal lobe BAs were assessed. Normal BPD and BPD subgroup comparisons were conducted. RESULTS: Compared with controls, BPD patients showed reduced gray matter volume in BA 24 and 31 of the cingulate. BPD patients without comorbid SPD had isolated gray matter volume loss in BA 24, but were spared for BA 31 in contrast to BPD patients with SPD. There were no group differences in whole cingulate or frontal lobe volume. CONCLUSIONS: The finding of more pervasive cingulate shrinkage in the patients with BPD and SPD comorbidity resembles recent observations with the same methods in patients with schizophrenia. The pattern of reduced anterior and posterior cingulate gray matter volume in BPD patients, particularly those comorbid for SPD is consistent with the affective and attentional deficits observed in these personality disorders.

Adult↗
PubMed2006

Dorsolateral prefrontal cortex and anterior cingulate cortex white matter alterations in late-life depression.

BACKGROUND: The dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) are critical for mood regulation. Alterations in the white matter connections of these regions may impair their role in mood regulation and increase the risk of developing depression. This study used diffusion tensor imaging to examine for white matter microstructural abnormalities of these regions and of central white matter structures in late-life depression. METHODS: One hundred six elderly depressed subjects and eighty-four elderly nondepressed subjects underwent clinical assessment and diffusion tensor imaging. The apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured in regions of interest placed in the white matter of the DLPFC, ACC, corpus callosum, and internal capsule. Differences between groups were assessed, controlling for age, sex, and total cerebral volume. RESULTS: After controlling for covariates, depressed subjects had significantly lower FA values in white matter of the right ACC, bilateral superior frontal gyri, and left middle frontal gyrus. There were no significant differences in ADC values. CONCLUSIONS: Lower FA, representing lower tissue organization, is observed in depressed elders in the DLPFC and right ACC. These findings support the hypothesis that altered connectivity between brain regions contributes to the risk of depression.

Aged↗