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Biomedical subjects

W M Brooks

Publications and source records attributed to W M Brooks.

At least 37 records · Page 2Linked to original sources
PubMed1999

Relationship between neurometabolite derangement and neurocognitive dysfunction in systemic lupus erythematosus.

OBJECTIVE: To determine the relationship between neurochemical markers of brain injury and brain dysfunction associated with systemic lupus erythematosus (SLE). METHODS: Patients with SLE (n = 12) were studied using magnetic resonance spectroscopic imaging at 1.5 Tesla to determine neurochemistry and a neurocognitive testing battery to determine brain dysfunction. N-acetylaspartate (NAA), creatine (Cre), and choline (Cho) concentrations were measured in white (WM) and gray (GM) matter and expressed as the ratios NAA/Cho, NAA/Cre, and Cho/Cre. Neurocognitive testing results were expressed as a composite z score. Disease activity was quantified by SLE Disease Activity Index (SLEDAI) and disease injury by Systemic Lupus International Collaborating Clinics (SLICC)/American College of Rheumatology Damage Index. RESULTS: Neurochemical measures of brain injury were correlated with neurocognitive testing z scores: NAA/Cho in WM (r = 0.77, p = 0.003) and GM (r = 0.67, p = 0.017); WM Cho/Cre also correlated with total z score (r = -0.74, p = 0.006). Neurometabolite ratios and SLICC were correlated: GM NAA/Cho (r = -0.70, p = 0.011 ) and NAA/Cre (r = -0.71, p = 0.01) and WM Cho/Cre (r = 0.66, p = 0.02). Correlations between neurometabolite ratios and SLEDAI did not reach significance. CONCLUSION: Brain function is closely correlated with brain injury assessed noninvasively by proton magnetic resonance spectroscopy. This important finding further supports the use of magnetic resonance spectroscopy to evaluate brain injury in SLE.

Adult↗
PubMed1998

Frontal lobe of children with schizophrenia spectrum disorders: a proton magnetic resonance spectroscopic study.

BACKGROUND: Schizophrenia is commonly considered a neurodevelopmental disorder. Our aim was to determine whether the proton magnetic resonance spectroscopic (1H-MRS) changes seen in adults with schizophrenia are displayed in children at risk for developing schizophrenia. METHODS: Children with symptoms of schizophrenia-spectrum disorders (n = 16; mean age = 132 months) and a comparison group (n = 12; mean age 130 months) took part in a 1H-MRS study of the left frontal lobe. Areas of peaks from N-acetylaspartate (NAA), choline (Cho), and creatine (Cre) were determined and ratios of NAA/Cre and Cho/Cre calculated and compared between groups. RESULTS: The mean ratio of NAA/Cre was significantly lower in schizophrenia-spectrum subjects than the comparison group (1.67 vs. 1.92; p < .05). Medication status did not affect results in schizophrenia-spectrum subjects. CONCLUSIONS: Our findings suggest that the metabolic changes associated with adult schizophrenia are observed in children with some or all of the symptoms of schizophrenia, supporting a neurodevelopmental theory for schizophrenia.

Antipsychotic Agents↗
PubMed1998

Structural and neurochemical markers of brain injury in the migraine diathesis of systemic lupus erythematosus.

OBJECTIVE: To determine whether migraine in systemic lupus erythematosus (SLE) is associated with accentuated brain injury and disease activity. METHODS: Forty SLE patients (11 without headache, 11 with non-migraine headache, and 18 with migraine) underwent clinical evaluation, magnetic resonance imaging (MRI), and spectroscopy (MRS). RESULTS: Recurrent headache occurred in 75% of SLE patients. MRI abnormalities and reduced N-acetylaspartate were common. However, migraine in SLE was not associated with increased disease activity or severity, neuropsychiatric manifestations, or end-organ involvement compared to patients without migraine (p > 0.05). There were no differences in the prevalence or severity of MRI or MRS abnormalities between SLE patients with migraine, with non-migraine headache, or without headache (p > 0.05). CONCLUSIONS: Headache does not identify SLE patients at risk for brain injury, increased disease activity, or increased end-organ involvement. Aggressive immunosuppressive therapy for headache alone is not indicated in SLE.

Adolescent↗
PubMed1998

Brain injury and neurometabolic abnormalities in systemic lupus erythematosus.

PURPOSE: To investigate with statistical analysis the relationship between brain injury measured with magnetic resonance (MR) imaging and that measured with proton (hydrogen-1) MR spectroscopy. MATERIALS AND METHODS: Forty-two patients (34 female, eight male; mean age +/- SD, 38.7 years +/- 13.1; age range, 6-60 years) with systemic lupus erythematosus (SLE) were examined with H-1 MR spectroscopy to measure N-acetylaspartate (NAA), creatine (Cr), and choline (Cho) levels in normal-appearing white matter and with MR imaging to detect anatomic abnormalities. RESULTS: Results of linear regression analysis revealed an association between the NAA/Cr ratio and anatomic abnormalities (P = .03). However, only small focal lesions were independently related to NAA/Cr ratio changes (P = .04). Results of a similar analysis showed associations between the Cho/Cr ratio and anatomic abnormalities (P = .002). An elevated Cho/Cr ratio and cerebral infarction were independently associated (P = .02), as were a decreased Cho/Cr ratio and severe cortical atrophy (P = .02). CONCLUSION: Cerebrovascular abnormalities underlie diffuse cerebral injury in SLE, with small vessel injury (i.e., small focal lesions) primarily associated with a decreased NAA/Cr ratio and medium vessel injury (i.e., infarct) primarily associated with an increased Cho/Cr ratio. Statistical integration of H-1 MR spectroscopic and MR imaging findings over large data sets provides insights into the relevance of individual MR imaging-visible brain abnormalities in SLE. This statistical approach may be applicable to other systemic diseases complicated by brain injury.

Adolescent↗
PubMed1998

Neurometabolite markers of cerebral injury in the antiphospholipid antibody syndrome of systemic lupus erythematosus.

BACKGROUND AND PURPOSE: To determine the neurometabolic patterns of brain injury in systemic lupus erythematosus with antiphospholipid antibody syndrome (SLE-aPLS). METHODS: Forty-nine SLE patients (12 SLE-aPLS) and 23 control subjects were studied using magnetic resonance imaging and spectroscopy. N-Acetylaspartate/creatine (NAA/Cre) and choline/Cre (Cho/Cre) were measured in normal-appearing tissue. IgG and IgM antiphospholipid antibodies (aPL) were measured by enzyme-linked immunosorbent assay. RESULTS: Stroke, epilepsy, and elevated IgG-aPL were more common in SLE-aPLS patients than in SLE patients (P<0.001). NAA/Cre was lower (P<0.05) and Cho/Cre higher (P<0.001) in SLE-aPLS patients than in SLE patients without aPLS. Regression models showed NAA/Cre was most related to injury seen by imaging (P<0.01), disease duration (P<0. 05), and prior neuropsychiatric SLE (NPSLE) (P=0.07). Reduced NAA/Cre was more closely related to IgG-aPL (P<0.01) than the presence of stroke or aPLS. When adjusted for all factors, Cho/Cre was most associated with the presence of aPLS (P=0.05). CONCLUSIONS: SLE and SLE-aPLS are actually a clinical continuum describing brain injury in SLE, with SLE-aPLS being characterized by increased aPL, NPSLE, stroke, epilepsy, and disturbed neurochemistry. An elevated IgG-aPL level is a potent risk factor for brain injury as measured by NAA/Cre in SLE that is independent of stroke and aPLS. However, thrombotic phenomena and the presence of aPL (aPLS) are most closely associated with increased Cho/Cre in SLE. These results suggest that aPLs exacerbate SLE, resulting in increased thrombotic and nonthrombotic brain injuries. Spectroscopy detects brain injury in SLE and may permit better understanding of the neurological consequences of SLE and SLE-aPLS.

Adult↗
PubMed1997

Brain abnormalities in schizophrenia-spectrum children: implications for a neurodevelopmental perspective.

Children with symptoms of schizophrenia-spectrum disorder (N = 20) were compared to controls (N = 20) matched for age and socioeconomic status. Structural brain abnormalities were assessed with magnetic resonance imaging and functional brain abnormalities with neuropsychological tests. Children with schizophrenia-spectrum disorder had smaller amygdala and temporal cortex volumes, along with reduced callosal areas and an unusual pattern of neuroanatomic asymmetries. No differences were noted in overall brain volume, ventricular volume, hippocampal volume, or frontal area. Schizophrenia-spectrum children were also characterized by deficits in all neuropsychological functions examined. Some types of verbal memory and frontal lobe skills were especially deficient. These results support the hypothesis that children with schizophrenia-spectrum disorder have significant brain abnormalities, similar in some ways to those seen in adult schizophrenics. In conjunction with recent primate studies, the current results draw attention to the role of the amygdala as one relevant factor in the pathogenesis of schizophrenia.

Brain↗
PubMed1997

1H-MRS differentiates white matter hyperintensities in subcortical arteriosclerotic encephalopathy from those in normal elderly.

BACKGROUND AND PURPOSE: White matter hyperintensities in MRI of the brain are often seen in normal elderly subjects. Radiologically, these hyperintense regions are similar to those in symptomatic patients with subcortical arteriosclerotic encephalopathy (SAE). Our aim was to discriminate white matter hyperintensities (WMH) on MRI in patients with SAE from similar appearing changes in normal elderly. METHODS: Three groups of elderly patients were studied: symptomatic patients with WMH of SAE (n = 5); asymptomatic subjects with diffuse, confluent WMH (n = 4); and elderly control subjects (n = 5). Proton density images revealed WMH in the occipital lobes. Proton magnetic resonance spectroscopy (1H-MRS) was used to acquire spectra in these hyperintensities. Metabolite concentrations were calculated from peak areas of N-acetylaspartate (NAA), creatine (Cre), and choline (Cho). RESULTS: The NAA/Cre and NAA/Cho ratios were reduced in the SAE group compared with the two asymptomatic groups (P < .05). NAA was decreased and Cho elevated in SAE compared with control subjects (P < .05). The average volumes of WMH in the SAE group (65.5 cm3) and in asymptomatic control subjects (59.4 cm3) were similar, and greater than those of the normal control group (4.0 cm3). CONCLUSIONS: Proton MRS discriminates WMH in SAE patients from those in asymptomatic elderly, suggesting differing causes of the hyperintensities.

Aged↗
PubMed1997

Neurometabolism of active neuropsychiatric lupus determined with proton MR spectroscopy.

PURPOSE: To determine the neurometabolism of patients with active neuropsychiatric systemic lupus erythematosus (NPSLE) by using proton MR spectroscopy. METHODS: Thirty-six patients with SLE and eight control subjects were studied with proton MR spectroscopy to measure brain metabolites. Peaks from N-acetylaspartate (NAA), creatine (Cr), choline (Cho), and at 1.3 parts per million (ppm) lipid, macromolecules, and lactate were measured. Patients were classified as having major NPSLE (seizures, psychosis, major cognitive dysfunction, delirium, stroke, or coma) (n = 15) or minor NPSLE (headache, minor affective disorder, or minor cognitive disorder) (n = 21). Patients with major NPSLE were severely ill and hospitalized. RESULTS: SLE patients had lower NAA and increased metabolites at 1.3 ppm than did control subjects (NAA/Cr(SLE) = 1.90 +/- 0.35, NAA/Cr(Control) = 2.16 +/- 0.26; 1.3 ppm/Cr(SLE) = 0.49 +/- 0.41, 1.3 ppm/Cr(Control) = 0.27 +/- 0.05). NAA/Cr in patients with current or prior major NPSLE was lower than in patients without major NPSLE. Increased peaks at 1.3 ppm were present in all SLE subgroups, but particularly in patients with major NPSLE. These resonances were not evident at an echo time of 136, indicating that these signals were not lactate. CONCLUSION: Major NPSLE, past or present, is associated with decreased levels of NAA. Elevated peaks around 1.3 ppm do not represent lactate even in severely ill patients, indicating that global ischemia is not characteristic of NPSLE. Neurochemical markers determined by MR spectroscopy may be useful for determining activity and degree of brain injury in NPSLE.

Adult↗
PubMed1997

Neurochemistry of brain lesions determined by spectroscopic imaging in systemic lupus erythematosus.

OBJECTIVE: The significance and etiology of focal brain lesions in systemic lupus erythematosus (SLE) are unknown. Our purpose was to determine whether the neurochemistry of focal lesions and normal appearing brain tissues in SLE were consistent with neuronal loss, demyelination, or ischemia. METHODS: Patients with SLE (n = 14) and controls (n = 13) were studied using magnetic resonance imaging (MRI) and spectroscopic imaging (SI) at 1.5 Tesla. RESULTS: MRI detected fixed focal brain lesions (n = 16) and SI measured brain metabolites, including N-acetylaspartate (NAA), creatine (Cre), choline (Cho), and lactate (Lac). NAA/Cre of normal appearing brain was decreased in patients with SLE compared to controls: grey matter (1.74 +/- 0.16 vs 1.92 +/- 0.18; p = 0.01), occipital white matter (1.98 +/- 0.22 vs 2.23 +/- 0.16; p = 0.004), and periventricular white matter (2.00 +/- 0.23 vs 2.33 +/- 0.23; p = 0.001). Lesions were characterized by markedly decreased NAA/Cre relative to normal appearing tissues in the same patient (1.67 +/- 0.22 vs 1.88 +/- 0.14; p = 0.0002). Elevated Cho/Cre was observed in 25% of focal lesions and 21% of normal appearing tissues. No elevation of lactate was observed in lesions or normal appearing tissues. CONCLUSION: SI detects focal and generalized brain abnormalities in SLE characterized by decreased NAA, elevated choline, and normal lactate. These findings are consistent with widespread neuronal injury and demyelination, but are not consistent with anaerobic metabolism.

Adult↗
PubMed1996

Proton magnetic resonance spectroscopy of vascular- and Alzheimer-type dementia.

OBJECTIVE: To identify biochemical differences in brain tissue between patients with dementia of the Alzheimer type and vascular dementia. DESIGN AND SUBJECTS: Proton magnetic resonance spectroscopy was used to compare 10 patients with dementia of the Alzheimer type and 8 age-matched patients with vascular dementia. RESULTS: The ratios of N-acetyl groups to creatine and N-acetyl groups to choline were lower in regions of subcortical white matter in patients with vascular dementia than in patients with dementia of the Alzheimer type (P < .02). CONCLUSION: Proton magnetic resonance spectroscopy may be useful in distinguishing between dementia of the Alzheimer type and vascular dementia.

Aged↗
PubMed1995

Spin-spin relaxation of brain tissues in systemic lupus erythematosus. A method for increasing the sensitivity of magnetic resonance imaging for neuropsychiatric lupus.

OBJECTIVE: To correlate the spin-spin relaxation time (T2) of brain tissue in neuropsychiatric systemic lupus erythematosus (NPSLE) with the patient's clinical condition. METHODS: T2 values were determined in 54 SLE patients and 45 non-SLE controls at 1.5 Tesla, using intensity from multi-echo magnetic resonance (MR) images fitted to an exponential decay curve with rate-constant T2. RESULTS: The T2 of white matter was increased in SLE patients compared with controls (P = 0.01) and was increased in those patients who had previously experienced major NPSLE: Patients with acute diffuse neurologic manifestations (seizures, psychosis, coma) demonstrated a longer T2 of the gray matter (mean +/- SD 92.75 +/- 6.35 ms, n = 10) than did other SLE patients (mean +/- SD 79.61 +/- 5.04 ms, n = 44) (P = 0.02 by t-test), which suggests acute cerebral edema. The mean T2 values of reversible and nonreversible focal lesions were significantly different (P < 0.02), indicating different microenvironments and micropathology. CONCLUSION: Quantitative T2 measurement extends the utility and sensitivity of conventional MR imaging for evaluating NPSLE:

Adolescent↗
PubMed1995

Neuropsychophysiological study of children at risk for schizophrenia: a preliminary report.

OBJECTIVE: This initial report, from an ongoing study, examines whether children who have symptoms of schizophrenia spectrum disorder display neuropsychological or neuroanatomic abnormalities similar to those seen in adults with schizophrenia. METHOD: Experimental subjects were 12 children between 8 and 12 years of age who displayed symptoms of early-onset schizophrenia or schizotypal personality disorder, as assessed through the Schedule for Affective Disorders and Schizophrenia for School-Age Children. The experimental subjects were compared with 13 controls on neuropsychological test performance, magnetic resonance imaging measurements, and proton magnetic resonance spectroscopy results. RESULTS: Findings from the first phase of this project reveal significant overall group differences for several morphometric magnetic resonance imaging measurements and all neuropsychological measures. Differences between the groups were found for amygdala volume, mesial temporal volume, callosal area, and anatomic asymmetry. Magnetic resonance spectroscopy data showed a trend toward group differences. CONCLUSIONS: These findings support a neurodevelopmental model of schizophrenia which postulates that environmentally or genetically programmed events in utero disrupt the establishment of fundamental aspects of brain structure and function.

Age of Onset↗
PubMed1994

Effect of lordosis on the position of the nucleus pulposus in supine subjects. A study using magnetic resonance imaging.

STUDY DESIGN: Healthy young women (N = 20) underwent magnetic resonance imaging while supine with their hips and knees flexed (flexed position) and supine with a lumbar roll under the low back (extended position). The posterior and anterior margins of the nucleus pulposus (NP) relative to posterior and anterior margins of the adjacent vertebral bodies were calculated from mid-sagittal T2-weighted images to determine the position change of the NP as a function of two supine postures. OBJECTIVES: This study describes the effect of two commonly used supine postures on the position of the NP. SUMMARY OF BACKGROUND DATA: Management of patients with low back pain is often based on theorized positional changes of the NP during spinal extension and flexion. Data describing NP positional changes have not been reported for noninvasive measurements. RESULTS: The distance of the posterior margin of the NP to the posterior margins of the adjacent vertebral bodies was greater in the extended compared with the flexed position. There was no difference in the anterior distance. Eight of the 20 subjects had at least one degenerative disc in the lower lumbar spine. The NPs of the degenerative discs did not move the same as normal discs. CONCLUSIONS: The use of a lumbar roll under the low back when supine causes an increase in the distance from the posterior margin of the NP to the posterior portions of the vertebral bodies in normal discs of healthy young females. Degenerative discs deform differently from nondegenerative discs.

Adult↗
PubMed1994

Prevalence of protozoan infections in darkling beetles from poultry houses in North Carolina.

A study was conducted from November 1990 to February 1992 on the prevalence of protozoan infections in the darkling beetle, Alphitobius diaperinus (Coleoptera, Tenebrionidae), from turkey and broiler houses in the southeastern, northeastern, and central Piedmont regions of North Carolina. Darkling beetles were commonly infected with the eugregarine Gregarina alphitobii, an undescribed species of Gregarina (Eugregarinorida, Gregarinidae) and the neogregarine Farinocystis tribolii (Neogregarinorida, Lipotrophidae). Both eugregarine and neogregarine parasites were present throughout the sampling period. A decreasing trend in percentage infection by eugregarines in darkling beetles from broiler houses was observed through time while percentage infection in turkey houses showed a variable trend. Percentage neogregarine infection exhibited a variable trend with a significant difference in the overall rate of infection in the two types of production houses. Neogregarine infection was higher in the broiler houses than in the turkey houses. Both adult and larval stages of the beetle were infected with the gregarines with higher levels of infection observed in the larval stages. Mixed infections with both types of gregarines were highest in the smallest larvae.

Animals↗
PubMed1989

In vivo high-resolution volume-selected proton spectroscopy and T1 measurements in the dog brain.

Successful in vivo NMR spectroscopy requires a combination of techniques to address the problems of volume selection, water suppression, and resolution. All this needs to be done in the very heterogeneous environment found in living organisms. Previously published techniques are used to obtain 1H spectra from a dog brain, observing metabolites with concentrations below 1 mM. Measurements of spin-lattice relaxation times (T1) are also presented. The 1H relaxation times are long (T1 greater than 1.0 s) yielding information about the fluidity of the molecular environment. Comments are made concerning the achievable linewidth in vivo and the deficiencies that phase-encoding spectroscopic methods may have in obtaining high-resolution 1H spectra.

Animals↗
PubMed1988

Nodal inhomogeneity mapping by localized excitation--the "NIMBLE" shimming technique for high-resolution in vivo NMR spectroscopy.

A method (NIMBLE) for obtaining optimum B0 field homogeneity at voxels located away from the magnet isocenter for use in volume-selected NMR spectroscopy is described. Voxels may be shimmed using only first-order X, Y, and Z shims to produce three-dimensional shim current maps, thus avoiding shim coupling problems. NIMBLE shimming prior to volume selection ensures optimum spectral resolution and improves the efficiency and accuracy of the volume-selection experiment. The benefits of the technique are illustrated by a high-resolution volume-selected spectrum of human tibia marrow.

Humans↗
PubMed1987

Use of high resolution in vivo volume selected 1H-magnetic resonance spectroscopy to investigate leukemia in humans.

In vivo high resolution volume-selected 1H magnetic resonance spectroscopy of human tibia has been undertaken using spatial coordinates obtained from magnetic resonance images. Adult tibial marrow has a 1H spectrum rich in fatty acid resonances and is readily distinguished from the 1H spectra of surrounding leg muscle. In all four leukemic patients examined, infiltration of fat cells of tibial marrow by proliferating cells rich in mobile H2O protons was evident by magnetic resonance imaging. Selective examination of volumes of tibial marrow (1 cm3) by 1H magnetic resonance spectroscopy confirmed marked differences in the 1H spectra of marrow from these patients. Increases in the H2O peak of the 1H spectra were correlated with infiltration of blast cells and lack of control of the neoplastic disease. These studies are the first to report the use of volume selected magnetic resonance spectroscopy to selectively monitor leukemia in humans.

Adolescent↗