Extensive white matter dysfunction in cognitively impaired patients with secondary-progressive multiple sclerosis.

BACKGROUND AND PURPOSE: Cognitive impairment is a common, disabling symptom of MS. We investigated the association between cognitive impairment and WM dysfunction in secondary-progressive multiple sclerosis using DTI. MATERIALS AND METHODS: Cognitive performance was assessed with a standard neuropsychological battery, the Minimal Assessment of Cognitive Function in Multiple Sclerosis. Cognitive impairment was defined as scoring >1.5 standard deviations below healthy controls on ≥2 subtests. Fractional anisotropy maps were compared against cognitive status using tract-based spatial statistics with threshold-free cluster enhancement. RESULTS: Forty-five patients with secondary-progressive multiple sclerosis (median age: 55 years, female/male: 27/18, median Expanded Disability Status Scale Score: 6.5) were prospectively recruited. Cognitively impaired patients (25/45) displayed significantly less normalized global GM and WM volumes (P = .001, P = .024), more normalized T2-weighted and T1-weighted WM lesion volumes (P = .002, P = .006), and lower WM skeleton fractional anisotropy (P < .001) than non-impaired patients. Impaired patients also had significantly lower fractional anisotropy (p(corr) < .05) in over 50% of voxels within every major WM tract. The most extensively impinged tracts were the left posterior thalamic radiation (100.0%), corpus callosum (97.8%), and right sagittal stratum (97.5%). No WM voxels had significantly higher fractional anisotropy in patients with cognitive impairment compared with their non-impaired counterparts (p(corr) > .05). After the inclusion of confounders in a multivariate logistic regression, only fractional anisotropy remained a significant predictor of cognitive status. CONCLUSIONS: Cognitively impaired patients with secondary-progressive multiple sclerosis exhibited extensive WM dysfunction, though preferential involvement of WM tracts associated with cognition, such as the corpus callosum, was apparent. Multivariate analysis revealed that only WM skeleton fractional anisotropy was a significant predictor of cognitive status.

Normal-appearing white matter permeability distinguishes poor cognitive performance in processing speed and working memory.

BACKGROUND AND PURPOSE: Secondary-progressive MS is characterized by reduced acute inflammation and contrast enhancement but with increased axonal degeneration and cognitive/clinical disability that worsens with advanced disease. Relative recirculation, extracted from DSC is a surrogate measure of BBB integrity. We hypothesized that normal-appearing white matter relative recirculation is reduced in cognitively impaired compared with nonimpaired secondary-progressive MS, reflecting more advanced disease. MATERIALS AND METHODS: Cognitive performance was classified as impaired or nonimpaired by use of Minimal Assessment of Cognitive Function In MS test components. Demographic data, brain parenchymal fraction, WM lesion fraction, and weighted mean normal-appearing white matter relative recirculation were compared in cognitively dichotomized groups. Univariate and multivariate logistic regressions were used to study the association between cognitive test results and normal-appearing white matter relative recirculation. RESULTS: The mean (SD) age of 36 patients with secondary-progressive MS studied was 55.9 ± 9.3 years; 13 of 36 (36%) patients were male. A highly significant difference between normal-appearing white matter relative recirculation and WM lesion relative recirculation was present for all patients (P < .001). Normal-appearing white matter relative recirculation in impaired patients was significantly lower than in nonimpaired subjects for the Symbol Digit Modalities Test (P = .007), Controlled Word Association Test (P = .008), and Paced Auditory Serial Addition Test (P = .024). The Expanded Disability Status Scale demonstrated an inverse correlation with normal-appearing white matter relative recirculation (r = -0.319, P = .075). After adjustment for confounders, significant normal-appearing white matter relative recirculation reduction persisted for the Symbol Digit Modalities Test (P = .023) and the Paced Auditory Serial Addition Test (P = .047) but not for the Controlled Word Association Test (P = .13) in impaired patients. CONCLUSIONS: Significant normal-appearing white matter relative recirculation reduction exists in cognitively impaired patients with secondary-progressive MS, localizing to the domains of processing speed and working memory.

Robust perfusion deficits in cognitively impaired patients with secondary-progressive multiple sclerosis.

BACKGROUND AND PURPOSE: Cognitive impairment is a common, disabling symptom of MS. We investigated the impact of cerebral perfusion and brain and lesion volumetry on cognitive performance in 45 patients with SPMS by using MR imaging. MATERIALS AND METHODS: Cognition was assessed by using a standard battery, the Minimal Assessment of Cognitive Function in Multiple Sclerosis. qCBF and qCBV maps were analyzed by using SPM and PLS. SPM was also used to conduct the GM, WM, and WML volumetric analyses. RESULTS: Both SPM and PLS demonstrated significantly reduced qCBV in the superior medial frontal cortex of impaired patients. PLS also revealed significantly lower qCBV in the bilateral thalami and caudate nuclei of impaired patients and identified a pattern of significantly attenuated qCBF similar to that of qCBV. Performance on the Symbol Digit Modalities Test, which assesses information-processing speed, correlated most strongly overall with cerebral perfusion. Focal (ie, voxelwise) analyses of GM, WM, and WML volume revealed no significant differences between patients with and without cognitive impairment, though global GM volume was significantly decreased and global WML volume was significantly increased in impaired patients. CONCLUSIONS: These results suggest that cognitively impaired patients with SPMS exhibit robust perfusion deficits in cortical and subcortical GM and impaired processing speed.

Decreased frontal lobe gray matter perfusion in cognitively impaired patients with secondary-progressive multiple sclerosis detected by the bookend technique.

BACKGROUND AND PURPOSE: There is increasing evidence implicating microvascular impairment in MS pathogenesis. Perfusion imaging offers a unique opportunity to investigate the functional impact of GM pathology. We sought to quantify differences in MR imaging-based bookend-derived cerebral perfusion between cognitively impaired and nonimpaired patients with SPMS. MATERIALS AND METHODS: Patients were prospectively recruited and assessed using MR imaging and the standard cognitive battery called the Minimal Assessment of Cognitive Function in MS. Patients exhibiting impairment on ≥ 2 individual tests were classified as cognitively impaired. Healthy controls were prospectively recruited and assessed using MR imaging to validate bookend assumptions. Structural and perfusion scans were coregistered and partitioned into anatomic brain regions and tissue compartments. Clinical and radiologic characteristics were compared between patients with and without impairment to identify potential confounders. A Bonferroni adjusted P value threshold (P < .005) was used for lobar and sublobar level analyses to correct for multiple comparisons. RESULTS: Thirty-seven patients with SPMS (age 56 ± 9 years; 23 women, 14 men) and 10 age- and sex-matched healthy controls were recruited. Bookend assumptions were found to be valid in MS. GM and WM qCBV were all globally reduced in impaired patients. After adjusting for potential confounders while examining sublobar level perfusion, only GM qCBV was significantly different between cognitive groups, and this hypoperfusion localized to the bilateral medial superior frontal regions and left inferior, middle, and superior frontal regions (P < .005) of impaired patients compared with nonimpaired patients. GM qCBV accounted for 22.5% of the model variance compared with a model including only confounders (P = .0007). CONCLUSIONS: Bookend-derived GM qCBV was significantly reduced in cognitively impaired patients with SPMS in functionally relevant brain regions.

A SPECT study of sleep disturbance and Alzheimer's disease.

BACKGROUND/AIMS: This study aimed to investigate the possible association of regional cerebral perfusion and sleep loss in Alzheimer's disease (AD). METHODS: 55 AD patients were characterized as having (SL) or not having (NSL) nocturnal sleep loss based on standard AD scales assessing sleep over the previous 4 weeks. (99m)Tc-ethylcysteinate dimer SPECT scans were performed in a relaxed, wakeful state. Whole-brain analysis using Statistical Parametrical Mapping (SPM5) was performed to compare perfusion across groups. In addition, the AD groups were compared to normal control (NC) subjects of comparable age and gender to provide a context for interpretation of findings. RESULTS: SPM analysis showed increased perfusion in the right middle frontal gyrus (R-MFG, Brodman area 9, p = 0.016, familywise-error-corrected) in SL versus NSL patients. Comparison with NC subjects confirmed that perfusion in the R-MFG among SL patients did not exceed that found in NCs (relative rather than absolute hyperperfusion). CONCLUSIONS: In this sample of mild-to-moderate AD patients, relative hyperperfusion in the R-MFG is associated with reports of SL. This region may play a role in regulating sleep.

"Physical attractiveness stereotype" and the attribution of homosexuality revisited.

The present study investigated whether subjects would perceive male and female faces as homosexual based upon facial attractiveness while statistically controlling for facial masculinity/femininity. Also of interest was the extent to which the subjects' gender and attitudes toward homosexuality would influence their perceptions. Eighty undergraduates indicated how likely they thought it was that six male and six female faces were homosexual. The targets were also rated on attractiveness and masculinity/femininity. The present sample also completed the Index of Homophobia, the Bem Sex Role Inventory, the Attitude Toward Women Scale, a conservatism scale, and a demographic questionnaire. The subjects assigned higher homosexuality ratings to the unattractive males and females compared to their attractive counterparts. Gender of subject and attitudes toward homosexuality did not significantly affect evaluations.

The L-arginine:nitric oxide pathway is the major source of plasma nitrite in fasted humans.

15N guanidino-labelled L-arginine was infused into fasted human volunteers giving, at equilibrium, a stable 1:10 ratio of 15N to 14N arginine in the plasma. Separate GC-MS assays were used to compare the degree of enrichment of plasma arginine, nitrite and nitrate and thus define the quantitative relationship between the L-arginine:nitric oxide (NO) pathway and the formation of these oxides of nitrogen. 15N nitrite enrichments rose to 8.3% (SD 0.5), five hours after the start of the infusion. In contrast, 15N nitrate enrichments apparently rose to only 1.6% (SD 0.4) at this time. This discrepancy could be explained by our finding that the commonly used Tesch GC-MS nitrate assay is subject to considerable interference from non-nitrate sources in plasma. Taking this into account, nitrate enrichments were similar to those observed for plasma nitrite. These results therefore indicate that the measurement of these compounds in plasma is a valid indicator of NO generation in fasted humans.

Nitric oxide is present in exhaled breath in humans: direct GC-MS confirmation.

The physiological role of nitric oxide (NO) is being investigated in many experimental and clinical settings. There is considerable evidence that NO is involved in the regulation of lung vascular function. In addition there are many studies reporting the beneficial effect of NO inhalation. NO formed from L-Arginine has been detected in exhaled breath using indirect mass spectrometry and chemiluminescence. Both methods provided good evidence for the presence of NO in breath samples but were not unequivocal. We therefore developed a method using gas-chromatography-mass spectrometry which allowed us to measure trace levels of NO in air and breath. Eight healthy volunteers supplied numerous breath samples for analysis. A clear peak for nitric oxide was observed in seven volunteers. The mean level was 13ppb (n = 7, range < 2 to 19ppb). This data is in good agreement with our previous data and unequivocally confirms the presence of nitric oxide in human breath.

A rapid and simple method for the measurement of nitrite and nitrate in plasma by high performance capillary electrophoresis.

Quantification of nitric oxide in vivo is difficult because of its short half-life. Instead the oxidised products, nitrite and nitrate, are commonly used as indices of nitric oxide generation. We describe here a simple method for the measurement of nitrite and nitrate in plasma using high performance capillary electrophoresis. Plasma standard curves gave regression coefficients of 0.98 for nitrite and 0.99 for nitrate with an intra-assay coefficient of variance of 4.6% for 50 microM nitrite (n = 10) and 1.2% for 50 microM nitrate (n = 10). The assay allows measurement of nitrite and nitrate in a single analysis requiring minimal sample preparation, and with the sensitivity to detect both basal and physiological changes in plasma nitrite and nitrate.

Thermospray tandem mass spectrometric analysis of oxygen incorporation into citrulline by nitric oxide synthase.

Citrulline is formed as a co-product in the biosynthesis of nitric oxide from L-arginine by the action of either constitutive or inducible nitric oxide synthase which is present in a variety of cells. We have previously shown that the oxygen atom incorporated into both nitric oxide and citrulline derives from molecular oxygen and not water. This paper describes the tandem mass spectrometric analysis of citrulline synthesized by the macrophage cell line J774 in the presence of native or guanidino-labelled arginine and air or isotopically enriched oxygen. The results confirm that oxygen is incorporated into the ureido position of citrulline.

Constitutive and inducible nitric oxide synthases incorporate molecular oxygen into both nitric oxide and citrulline.

Nitric oxide (NO) is synthesized by a number of cells from a guanidino nitrogen atom of L-arginine by the action of either constitutive or inducible NO synthases, both of which form citrulline as a co-product. We have determined the source of the oxygen in both NO and in citrulline formed by the constitutive NO synthase from the vascular endothelium and brain and by the inducible NO synthase from the murine macrophage cell line J774. All these enzymes incorporate molecular oxygen both into NO and into citrulline. Furthermore, activated J774 cells form NO from omega-hydroxyl-L-arginine, confirming the proposal that this compound is an intermediate in the biosynthesis of NO.

Sex-role and opposite-sex interpersonal attraction.

Androgynous, traditional, and undifferentiated male and female subjects indicated their attraction to three opposite-sex strangers who were described as having an androgynous, traditional, and undifferentiated sex-role. Subjects' ability to describe the sex-roles of the strangers was also measured. Androgynous strangers were most preferred, undifferentiated strangers least preferred. The least preferred undifferentiated strangers' sex-role was most accurately described. Subjects were least successful in describing the androgynous sex-role.

Is there a central nervous withdrawal syndrome associated with discontinuing long-term treatment with propranolol?

Thirty healthy volunteers were treated with beta-adrenoceptor blocking doses of long-acting propranolol for at least 28 days before being randomized to continue propranolol treatment, receive identical placebo under double-blind conditions, or discontinue all treatment. No evidence of a central nervous withdrawal syndrome occurred during the next 28 days as assessed by changes in psychomotor tests, rating scales, visual analogue scales, tremor recordings and melatonin excretion. Three subjects in the placebo withdrawal group but none in the propranolol group complained of insomnia for up to 14 days of the withdrawal period.

Rapid and simple synthesis for the sulphate esters of 6-hydroxy-melatonin and N-acetyl-serotonin.

Melatonin is metabolised by hydroxylation at the 6 position and to a variable extent by demethylation. Both metabolites so formed are excreted as sulphate and, to a lesser extent, glucuronide conjugates. To authenticate these metabolites which we had earlier isolated from urine, we wished to have synthetic samples. Since we also required them as standards we needed them as powders. A review of the literature showed that there were only two published methods, of which only one gave rise to 6-sulphatoxy-melatonin (SaMT) as a solid. The other metabolite, N-acetyl-serotonin-sulphate (SNAS), has not been previously made, and we here describe some of its chemical properties. Our method modifies a published method taking into account the results given in a recent paper describing the sulphation of the thyroid hormones, T3 and T4. Hydroxy-melatonin is thus reacted with a complex formed from dimethylformamide and chlorosulphonic acid. The reaction is of interest since it is rapid, easy, and produces pure powdered material in excellent yield.

Constant pineal output and increasing body mass account for declining melatonin levels during human growth and sexual maturation.

Twenty-four-h urine samples, divided into two fractions representing night- and daytime melatonin production, were collected from 115 healthy individuals between the ages of 3 and 80, of known height and weight, and assayed for 6-hydroxy melatonin sulphate (SaMT), a major urinary metabolite of melatonin, by gas chromatography mass spectrometry. The population was divided for analytical purposes into children (boys aged 3-10.99, girls aged 3-9.59), adolescents (males aged 11-17.99, females aged 9.60-17.99), and adults (men and women over 18). The results showed approximately the same excretion over 24 h in all 3 groups but that the night/day ratio was considerably greater in children and adolescents compared to adults (P less than 0.001). However, when the results were expressed as a function of body weight (BW), body surface area (BSA), or creatinine excretion (CE), nocturnal SaMT was higher in children than in adults (P less than 0.001 for all 3 parameters) or adolescents (BW, P less than 0.001; BSA, P less than 0.002; CE, P less than 0.001) and was higher in adolescents than in adults (BW and BSA, P less than 0.001). Children also excreted more during the day than adults (BW, P less than 0.01; CE, P less than 0.001) or adolescents (BW alpha CE, P less than 0.02). Our results show that pineal output barely changes during childhood and adolescence. However, there is an age related decrease in SaMT excretion/unit body mass which correlates with an age-related increase in body mass. We therefore conclude that the decrease in circulating levels of melatonin during growth and sexual maturation is brought about by an increase in body mass.

Gas chromatographic-mass spectrometric assay for 6-hydroxymelatonin sulfate and 6-hydroxymelatonin glucuronide in urine.

Circulating melatonin is hydroxylated to 6-hydroxymelatonin and excreted in urine as the sulfate and glucuronide conjugates. We extracted these two compounds from urine by using octadecylsilane-bonded silica cartridges to eliminate most of the urea and electrolytes, and silica cartridges to separate the sulfate and glucuronide conjugates. After hydrolyzing the separated conjugates enzymically, we determined the free hydroxymelatonin by gas chromatography-mass spectrometry. Though recoveries were low and variable, we were able to quantify the analyte in the original sample by adding deuterated sulfate and glucuronide conjugates to the urines before extraction.

The isolation, purification, and characterisation of the principal urinary metabolites of melatonin.

Melatonin is metabolised by hydroxylation to form 6-hydroxy-melatonin and by demethylation to form N-acetyl-serotonin, which are excreted as sulphate and glucuronide conjugates. We required these metabolites as pure powders and therefore undertook their isolation and characterisation. Three volunteers ingested 1 g each of melatonin, and their urine was collected and pooled. For the sulphate conjugates, a Lichoprep column was used to concentrate the metabolites and to remove most of the urea. The sulphate conjugates were separated from the glucuronides on a Florisil column and further purified on a fractogel column. They were separated by high-performance liquid chromatography (HPLC) resulting in white powders of 6-hydroxy-melatonin sulphate (SaMT) and N-acetyl-serotonin sulphate (SNAS). For the glucuronide conjugates, an aliquot of the pooled urine was taken to dryness, the residue was dissolved in methanol, and the solution was filtered. The methanol filtrate was taken to dryness, and the residue was applied to a Florisil column. The isolated glucuronide conjugates were recrystallized prior to separation by HPLC, which gave pure white powders of N-acetyl-serotonin glucuronide (GNAS) and 6-hydroxy-melatonin glucuronide (GaMT). Characterisation was achieved by using infrared and ultraviolet spectroscopy, thin-layer chromatography (TLC), and gas chromatography-mass spectrometry (GCMS). These techniques unambiguously confirmed the assigned structures for SaMT and SNAS and fully supported the assigned structures for GNAS and GaMT. Three TLC solvent systems were used, and in each case the individual conjugated metabolite appeared as a discreet spot. Purity, as assessed by GCMS, was shown to be greater than 95% for SNAS, SaMT, and GaMT and to be 88% for GNAS.

Behavioral assessment of a hydranencephalic neonate.

This study attempted to clarify the role of the cerebral cortex in neonatal behavior by administering the Neonatal Behavioral Assessment Scale-Kansas revision to a hydranencephalic infant; particularly of interest were behaviors that are implicated in infant social responsiveness. The examination revealed extremely deviant responses on portions of the exam, including items that measure response decrement and orientation. However, this infant was observed to approximate normal neonatal responding on items relating to motor maturity and reactivity. Other findings included that some response decrement occurred in response to auditory and visual, but not tactile, stimulation. The discussion focuses on similarities and differences between this study and early research on both normal infants and infants with imperfectly formed nervous systems. Particular emphasis is placed on the response decrement results, as well as the utility of the NBAS-K in measuring infant behaviors in atypical infant samples.

Acyltryptophols reversibly inhibit muscle contractions caused by the actions of acetylcholine and raised potassium ion concentrations.

1. Acetylmethoxytryptophol, originally isolated from the pineal gland, inhibits both the nicotinic and muscarinic receptor stimulatory activities of acetylcholine on frog rectus muscle and guinea pig ileum. 2. Synthetic homologues and analogues, including the acetyl-, propionyl-, butyryl-, and valeryl-methoxytryptophols, tryptophols and alpha-methyl-tryptophols have been prepared and shown to possess similar activity on the frog muscle, with butyryl compounds being the most active. Methoxytryptophol, tryptophol, alpha-methyltryptophol and acetylhydroxytryptophol possess little or no activity. 3. All acyltryptophols tested inhibit the effect of increased potassium concentrations on frog muscle. 4. It is concluded that the acyltryptophols act not at the transmitter receptor level but either at the potassium ion channel or elsewhere in the cell membrane.