NMR assignment of actin depolymerizing and dynamics regulatory protein from Leishmania donovani

Leishmania donovani cofilin displays low sequence similarity to other mammalian cofilins and also possesses characteristic activity of its own. Determination of its solution structure would facilitate understanding of the molecular mechanism of actin dynamics regulation in this disease causing pathogen.

Deep gray matter T2 hypointensity is present in patients with clinically isolated syndromes suggestive of multiple sclerosis

Gray matter (GM) magnetic resonance imaging (MRI) T2 hypointensity, a putative marker of iron deposition, is a frequent finding in patients with clinically definite (CD) multiple sclerosis (MS). The objective of this study was to assess: (a) how early deep GM T2 hypointensity occurs in MS, by studying patients with clinically isolated syndromes (CIS) suggestive of MS, and (b) whether they contribute to predict subsequent evolution to CDMS. Dual-echo scans using two different acquisition protocols were acquired from 47 CIS patients and 13 healthy controls (HC). Normalized T2-intensity of the basal ganglia and thalamus was quantified. Patients were assessed clinically at the time of MRI acquisition and after three years. During the observation period, 18 patients (38%) evolved to CDMS. At the baseline, only the GM T2-intensity of the left caudate nucleus was significantly reduced in CIS patients in comparison with the HC (p = 0.04). At the baseline, the T2 intensity of the left caudate nucleus was significantly lower (p = 0.01) in CIS patients with disease dissemination in space (DIS), but not in those without DIS, compared to the HC. The baseline T2 lesion volume, but not GM T2 hypointensity, was associated with evolution to CDMS (hazard ratio = 1.60, 95% confidence interval (CI) = 1.05-2.42; p = 0.02). In CIS patients, deep GM is not spared, suggesting that iron-related changes and neurodegeneration occurs early. The magnitude of such damage is only minor and not associated with an increased risk of evolution to CDMS.

Spinal cord lesions and clinical status in multiple sclerosis: A 1.5 T and 3 T MRI study

OBJECTIVE

Assess the relationship between spinal cord T2 hyperintense lesions and clinical status in multiple sclerosis (MS) with 1.5 and 3 T MRI.

METHODS

Whole cord T2-weighted fast spin-echo MRI was performed in 32 MS patients [Expanded Disability Status Scale (EDSS) score (mean+/-SD: 2+/-1.9), range 0-6.5]. Protocols at 1.5 T and 3 T were optimized and matched on voxel size.

RESULTS

Moderate correlations were found between whole cord lesion volume and EDSS score at 1.5 T (r(s)=.36, p=0.04), but not at 3 T (r(s)=0.13, p=0.46). Pyramidal Functional System Score (FSS) correlated with thoracic T2 lesion number (r(s)=.46, p=0.01) and total spinal cord lesion number (r(s)=0.37, p=0.04) and volume (r(s)=0.37, p=0.04) at 1.5 T. Bowel/bladder FSS correlated with T2 lesion volume and number in the cervical, thoracic, and total spine at 1.5 T (r(s) 0.40-0.57, all p<0.05). These MRI-FSS correlations were non-significant at 3 T. However, these correlation coefficients did not differ significantly between platforms (Choi's test p>0.05). Correlations between whole cord lesion volume and timed 25-foot walk were non-significant at 1.5 T and 3 T (p>0.05). Lesion number and volume did not differ between MRI platforms in the MS group (p>0.05).

CONCLUSIONS

Despite the use of higher field MRI strength, the link between spinal lesions and MS disability remains weak. The 1.5 T and 3 T protocols yielded similar results for many comparisons.

T2 hypointensity in the deep gray matter of patients with benign multiple sclerosis

Background

Gray matter (GM) magnetic resonance imaging (MRI) T2 hypointensity, a putative marker of iron deposition, commonly occurs in multiple sclerosis (MS). However, GM T2 hypointensity in benign MS (BMS) has not yet been characterized.

Objective

To determine the presence of deep GM T2 hypointensity in BMS, compare it to secondary progressive (SP) MS and assess its association with clinical and diffusion tensor (DT) MRI measures.

Methods

Thirty-five cognitively unimpaired BMS, 26 SPMS patients, and 25 healthy controls were analyzed for normalized T2-intensity in the basal ganglia and thalamus, global T2 hyperintense lesion volume, global atrophy, and white matter and GM DT metrics.

Results

BMS and SPMS patients showed deep GM T2 hypointensity compared with controls. T2 hypointensity was similar in both MS subgroups and moderately correlated ( r = −0.45 to 0.42) with DT MRI metrics. GM T2 hypointensity in BMS showed a weak to moderate correlation ( r = −0.44 to −0.35) with disability.

Conclusions

GM in BMS is not spared from structural change including iron deposition. However, while T2 hypointensity is related to global tissue disruption reflected in DT MRI, the expression of benign versus non-benign MS is likely related to other factors.

Rhodotorula mucilaginosa as a cause of persistent femoral nonunion

We present a case of postoperative infection which presented as nonunion fracture femur in a 30-year-old man due to Rhodotorula mucilaginosa. This is the first report of Rhodotorula infection in a patient with fracture nonunion. The patient underwent repeated surgical debridement and received intensive antibiotic therapy before the diagnosis was made. The diagnosis could have been made earlier if the fungal etiology had been suspected earlier. Early suspicion and diagnosis of infection with atypical yeasts could be under-reported because of difficulties in accurate diagnosis and a tendency of attributing isolates to specimen contamination.

Normal findings on brain fluid-attenuated inversion recovery MR images at 3T

BACKGROUND AND PURPOSE

Fluid attenuated inversion recovery (FLAIR) MR imaging of the brain has become a routine tool for assessing lesions in patients with suspected neurologic disorders. There is growing interest in 3T brain FLAIR MR imaging but little normative data are available. The purpose of this study was to evaluate the frequency and topography of cerebral hyperintensities seen with FLAIR MR imaging of the brain at 3T in a normal population and compare those findings to 1.5T.

MATERIALS AND METHODS

Whole-brain 2D FLAIR MR imaging was performed in 22 healthy controls (mean age, 44 +/- 8 years; range, 30-53 years) at 3T. Fifteen of these subjects also underwent 2D FLAIR at 1.5T, with similar optimized parameters and voxel size. Cerebral hyperintense areas, including discrete foci, anterior and posterior periventricular capping, diffuse parenchymal hyperintensity, septal hyperintensity, corticospinal tract hyperintensity, and CSF flow artifacts were assessed. The Spearman rank test assessed the correlation between discrete hyperintense foci and age. The Wilcoxon signed rank test compared foci detectability at 3T versus 1.5T.

RESULTS

FLAIR at 3T commonly showed hyperintensities such as discrete foci (mean, 10.68 per subject; at least 1 present in 68% of subjects), anterior and posterior periventricular capping, diffuse posterior white matter hyperintensity, septal hyperintensity, corticospinal tract hyperintensity, and ventricular CSF flow artifacts. FLAIR at 3T showed a higher hyperintense foci volume (170 +/- 243 versus 93 +/- 152 mm3, P < .01) and number (9.4 +/- 13 versus 5.5 +/- 9.2, P < .01) than at 1.5T. No significant differences (P = .68) in the length/diameter of individual discrete hyperintense foci were seen between 3T and 1.5T. Discrete foci volume (r = 0.72 at 3T, r = 0.70 at 1.5T) and number (r = 0.74 at 3T; r = 0.69 at 1.5T) correlated with age to a similar degree on both platforms. All discrete foci were confined to the noncallosal supratentorial white matter. The other nonfocal hyperintensities (anterior and posterior periventricular capping, diffuse parenchymal hyperintensity, septal hyperintensity, corticospinal tract hyperintensity, and CSF flow artifacts) were generally more common and prominent at 3T than at 1.5T.

CONCLUSIONS

Discrete and diffuse parenchymal brain white matter FLAIR hyperintensities are more common and prominent at 3T than at 1.5T in healthy volunteers.

Deep gray matter involvement on brain MRI scans is associated with clinical progression in multiple sclerosis

BACKGROUND

Conventional brain MRI lesion measures have unreliable associations with clinical progression in multiple sclerosis (MS). Gray matter imaging may improve clinical-MRI correlations.

METHODS

We tested if gray matter MRI measures and conventional measures of lesions/atrophy predicted clinical progression in a 4-year longitudinal study of 97 patients with MS. Baseline and follow-up brain MRI were analyzed for basal ganglia and thalamic normalized T2 signal intensity, whole brain T2-hyperintense lesion volume, and whole brain atrophy. Logistic regression tested the ability of baseline or on-study change in MRI to predict disability progression, as reported by area under the receiver operator characteristics curve (AUC).

RESULTS

Lower caudate T2-intensity at baseline (P= .04; AUC = .69) and on-study decreasing T2-intensity in the putamen (P= .03; AUC = .70) and thalamus (P= .01; AUC = .71) were the MRI variables associated with clinical progression when regression modeling was adjusted for length of follow-up interval, baseline EDSS, disease duration, age, and sex.

CONCLUSIONS

Gray matter T2-hypointensity, suggestive of excessive iron deposition is associated with worsening disability in patients with MS. Gray matter MRI assessment may be able to capture neurodegenerative aspects of the disease, with more clinical relevance than derived from conventional MRI measures. J Neuroimaging 2009;19:3-8.

Cassane diterpenes from Caesalpinia bonduc

Three cassane diterpene hemiketals, caesalpinolide-C, caesalpinolide-D, caesalpinolide-E and one cassane furanoditerpene were isolated from Caesalpinia bonduc. The molecular structures were elucidated using NMR spectroscopy in combination with IR, UV and mass spectral data and relative stereochemistries were determined through ROESY correlation. The isolated compounds were tested for their antiproliferative activity against MCF-7 (breast adenocarcinoma), DU145 (prostate carcinoma), C33A (Cervical carcinoma) and Vero (African green monkey kidney fibroblast) cells.

Predicting clinical progression in multiple sclerosis with the magnetic resonance disease severity scale

BACKGROUND

Individual magnetic resonance imaging (MRI) disease severity measures, such as atrophy or lesions, show weak relationships to clinical status in patients with multiple sclerosis (MS).

OBJECTIVE

To combine MS-MRI measures of disease severity into a composite score.

DESIGN

Retrospective analysis of prospectively collected data.

SETTING

Community-based and referral subspecialty clinic in an academic hospital.

PATIENTS

A total of 103 patients with MS, with a mean (SD) Expanded Disability Status Scale (EDSS) score of 3.3 (2.2), of whom 62 (60.2%) had the relapsing-remitting, 33 (32.0%) the secondary progressive, and 8 (7.8%) the primary progressive form.

MAIN OUTCOME MEASURES

Brain MRI measures included baseline T2 hyperintense (T2LV) and T1 hypointense (T1LV) lesion volume and brain parenchymal fraction (BPF), a marker of global atrophy. The ratio of T1LV to T2LV (T1:T2) assessed lesion severity. A Magnetic Resonance Disease Severity Scale (MRDSS) score, on a continuous scale from 0 to 10, was derived for each patient using T2LV, BPF, and T1:T2.

RESULTS

The MRDSS score averaged 5.1 (SD, 2.6). Baseline MRI and EDSS correlations were moderate for BPF, T1:T2, and MRDSS and weak for T2LV. The MRDSS showed a larger effect size than the individual MRI components in distinguishing patients with the relapsing-remitting form from those with the secondary progressive form. Models containing either T2LV or MRDSS were significantly associated with disability progression during the mean (SD) 3.2 (0.3)-year observation period, when adjusting for baseline EDSS score.

CONCLUSION

Combining brain MRI lesion and atrophy measures can predict MS clinical progression and provides the basis for developing an MRI-based continuous scale as a marker of MS disease severity.

Osteomyelitis variolosa: a report of two cases

We present 2 patients with osteomyelitis variolosa in both elbow joints--sequelae of smallpox. The condyles were elongated and the central portions of the distal humeri were absorbed and the elbow joints were unstable. One of the patients sustained a closed fracture of the distal humerus. The fracture united uneventfully following stabilisation and bone grafting. At the 13-year follow-up, the patient had satisfactory elbow function.

Utility of software analysis of esophageal manometry studies in patients with aperistalsis

Esophageal manometry is the gold standard for the diagnosis of esophageal aperistalsis. There is computer software that analyzes peristalsis on esophageal manometry, but this automated analysis has not been formally evaluated. Our primary aim was to evaluate the software analysis of esophageal aperistalsis by esophageal manometry in patients diagnosed with aperistalsis by an experienced clinician. Esophageal manometry studies from January 2006 to November 2007 were retrospectively reviewed for evidence of aperistalsis by an experienced clinician. All studies demonstrating aperistalsis were selected for further review. The automated analysis performed by our software program for each study was recorded. Agreement between the automated analysis and the clinician was measured by the proportion of agreement on the absence of peristalsis. Eighty-seven of the 962 esophageal manometry studies reviewed demonstrated aperistalsis. The automated analysis reported esophageal body peristalsis with wet swallows in 66 out of 87 patients (75.9%). In these patients, the software analyzed an average of 34.2% of the wet swallows as peristaltic. The agreement between the clinician's review and software analysis of aperistalsis was 24.1%. These data suggest there is poor agreement between the automated analysis of peristalsis and that of an experienced reviewer. Automated analysis cannot be relied upon in the diagnostic evaluation of esophageal aperistalsis as it overestimates the presence of peristalsis and may lead to incorrect diagnoses and management strategies.

Characterization of Rv3868, an essential hypothetical protein of the ESX-1 secretion system in Mycobacterium tuberculosis

Rv3868, a conserved hypothetical protein of the ESAT-6 secretion system of Mycobacterium tuberculosis, is essential for the secretion of at least four virulence factors. Each protein chain is approximately 63 kDa and assembles into a hexamer. Limited proteolysis demonstrates that it consists of two domains joined by a linker. The N-terminal domain is a compact, helical domain of approximately 30 kDa and apparently functions to regulate the ATPase activity of the C-terminal domain and the oligomerization. The nucleotide binding site is situated in the C-terminal domain, which exhibits ATP-dependent self-association. It is also the oligomerization domain. Dynamic fluorescence quenching studies demonstrate that the domain is proximal to the C terminus in the apoprotein and exhibits a specific movement upon ATP binding. In silico modeling of the domains suggests that Arg-429 of a neighboring subunit forms a part of the binding site upon oligomerization. Mutational analysis of binding site residues demonstrates that the Arg-429 functions as the important "sensor arginine" in AAA-ATPases. Protein NMR experiments involving CFP-10 and activity assays rule out a general chaperone-like function for Rv3868. On the other hand, ATP-dependent "open-close" movements of the individual domains apparently enable it to interact and transfer energy to co-proteins in the ESX-1 pathway.

Neuroimaging of toxic and metabolic disorders

Imaging of the brain, magnetic resonance imaging (MRI) in particular, is a key adjunctive tool in the diagnosis and management of toxic-metabolic disorders such as alcoholism, mitochondrial encephalopathies, disorders of iron or copper metabolism, exposure to carbon monoxide, radiotherapy, immunosuppressive agents, toluene, and recreational drugs. In this article, we review the neuroimaging findings of common toxic and metabolic disorders focusing on the role of conventional MRI. We also consider advanced imaging methods, such as magnetic resonance spectroscopy, diffusion MRI, and positron emission tomography. We hope this article will prove useful to trainees and practitioners in the clinical and imaging fields of the neurosciences.