Midbrain Ischemia Presenting as Vertical Gaze Palsy: Value of Diffusion-Weighted Magnetic Resonance Imaging

BACKGROUND

Conventional magnetic resonance imaging may fail to identify very small but clinically relevant acute subcortical brain infarcts. Diffusion-weighted magnetic resonance imaging (DWI) is very sensitive and specific for acute cerebral ischemia and should contribute to the early detection of such lesions.

METHODS

We analyzed 6 patients who presented with acute vertical gaze palsy and in whom DWI was performed within 1-6 days from symptom onset.

RESULTS

DWI accurately identified ischemia in an area supplied by the posterior thalamosubthalamic paramedian artery in all patients. T(2)-weighted and FLAIR imaging failed to identify the clinically relevant lesion in 2 and 3 patients, respectively.

CONCLUSION

DWI improves the clinicoanatomical correlation in patients presenting with supranuclear oculomotor disturbances.

Action of treosulfan in myelin-oligodendrocyte-glycoprotein-induced experimental autoimmune encephalomyelitis and human lymphocytes

Treosulfan (dihydroxybusulfane, DHB, L-threitol-1,4-bis [methane sulfonate]) is a cytostatic alkylating agent with a favorable profile of side effects. Myelin-oligodendrocyte-glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE) induced in DA (RT1(av1)) rats resembles multiple sclerosis (MS) in many aspects since central nervous system (CNS) pathology shows inflammation, demyelination and axonal loss. Moreover, DA rats develop a chronic disease course. We here explored the efficacy of treosulfan in the treatment of MOG-induced EAE in DA rats. A single dose of treosulfan (1 g/kg body weight i.p.) at the day of immunization significantly reduced disease severity compared with PBS-treated controls. In addition, after disease had evolved, a single dose of treosulfan (1 g/kg body weight) given i.p. on day 14 post-immunization (p.i.) improved long-term disease outcome. Treatment with treosulfan resulted in reduced mRNA expression of IL-12 and interferon (IFN)-gamma in draining lymph nodes and reduced numbers of IFN-gamma-secreting MOG-specific T cells. No myelosuppression was observed. Treosulfan was applied to different subsets of cultured human blood mononuclear cells in order to asses the effects on human immune cells in vitro: Treosulfan reduced proliferative capacity and increased apoptosis in T cells and antigen-presenting cells. In light of the beneficial effects in EAE in vivo and the in vitro immunosuppressive and pro-apoptotic capacities in cultured human mononuclear immune effector cells, these data may support a potential role of treosulfan, an agent with high immunosuppressive capacity and low toxicity, in the treatment of MS.

Manganiophosphonium-Salze: Synthese, Eigenschaften und Struktur von Komplexen des Typs [CpMn(CO)(NO)PPh2H]BF4 und [Cp′Mn(CO)(NO)PPh2R]X (R = H, CH3, {CpMn(CO)(NO)}; X = BF4, PF6)

The reaction of [Cp′Mn(CO)2NO]X (Cp = C5H5, C5H4Me = Cp′; X =BF4, PF6) with PPh2H leads to the formation of the diphenylmanganiophosphonium salts [{CpMn(CO)NO}PPh2H]X, which can be deprotonated by DABCO to give the not isolable manganiophosphane {CpMn(CO)NO}PPh2. This reactive intermediate, however, can be methylated by MeI and CF3SO3Me or organometallated by C5H5Fe(CO)2Cl to yield the phosphonium salts [{Cp′Mn(CO)NO}PPh2Me]PF6 and [{Cp′Mn(CO)NO}PPh2{C5H5Fe(CO)2}]PF6, respectively. The methyl derivative is deprotonated by πBuLi to give the unstable methylene phosphorane {Cp′Mn(CO)NO}PPh2=CH2, an organometallated phosphorus ylide. The in situ from [{Cp′Mn(CO)NO}PPh2H]BF4 generated phosphane {Cp′Mn(CO)NO}PPh2 is oxidized by epoxycyclohexane to give the intermediate oxophosphorane {Cp′Mn(CO)NO}P(O)Ph2, which reacts with the still available starting material to yield the first dimanganiodiphenylphosphonium salt [{Cp′Mn(CO)NO}2PPh2]BF4. The compounds have been characterized by spectroscopic (IR, NMR, MS), analytical (C, H, N) and X-ray diffraction investigations ([{C5H5Mn(CO)NO}PPh2H]BF4, [{Cp′Mn(CO)NO}PPh2Me]BF6, [{Cp′Mn(CO)NO}2PPh2]-BF4).

Method for quantitative imaging of the macromolecular 1H fraction in tissues

A new method was developed for mapping the relative density of the macromolecular protons involved in magnetization transfer (MT). This method employs a stimulated echo preparation scheme in order to modulate the phase distribution within a spin ensemble. This labeled spin ensemble is then used as an intrinsic indicator, which is diluted due to magnetization exchange with macromolecular protons. A pulse sequence is presented which compensates for longitudinal relaxation, allows observation of the dilution effect only, and provides for calculation of parameter maps using indicator dilution theory. Compared to other quantitative MT techniques, neither additional relaxation time measurements nor knowledge regarding the lineshape of the macromolecular proton pool are required. Moreover, the inherent low specific absorption rate and the low sensitivity for B(1) errors make this method favorable in a clinical setting. This sequence was used to measure the macromolecular proton density in cross-linked bovine serum albumin. Using a navigated echo planar readout, the sequence was also employed to visualize the macromolecular content of human brain in vivo.

TACE mRNA expression in peripheral mononudear cells precedes new lesions on MRI in multiple sclerosis

Tumor necrosis factor-alpha (TNF-alpha) is involved in the pathogenesis of multiple sclerosis (MS). It has to be released from its cell membrane-bound precursor by proteolytic cleavage. This is mainly performed by a member of the ADAM (a disintegrin and metalloproteinase) family of enzymes, TNF-alpha-converting enzyme (TACE, ADAM 17). In a longitudinal study on 11 relapsing-remitting MS patients, we qualitatively determined mRNA expression of TNF-alpha and TACE in peripheral blood mononuclear cells (PBMCs) without ex vivo stimulation. mRNA expression was related to disease activity as assessed by monthly gadolinium (Gd)-enhanced brain magnetic resonance imaging (MRI). Patients found positive for TACE mRNA in PBMCs showed a significantly higher mean number of new Gd-enhancing lesions per scan one month following PBMC sampling.

Quantitative magnetization transfer imaging of pre-lesional white-matter changes in multiple sclerosis

OBJECTIVE

Previous magnetization transfer (MT) studies in multiple sclerosis (MS) suggest a reduction of the MT ratio (MTR) precedes new lesion development. To gain further insight into pre-lesional tissue abnormalities, we investigated the time course of additional quantitative MT parameters.

METHODS

Serial magnetic resonance imaging (MRI), including a gadolinium-enhanced T1 scan and MT imaging by means of a FastPACE sequence, was performed on 12 patients (4 males, 8 females) with relapsing-remitting MS. Quantitative MT values including the magnetization exchange rate (kfor) and the native relaxation time (T1free were analysed in the six months prior to the appearance of 44 enhancing lesions and in 88 control regions of persistently normal-appearing white matter (NAWM).

RESULTS

Appearance of new active lesions was preceded by a significant decrease of the MTR (F7,166=91.5; p<0.0001) and of kfor (F7,166=105.2; p<0.0001), and by an increase of T1free (F7,166=57.3; p<0.0001). The drop of kfor was the most pronounced pre-lesional change and together with the MTR was statistically significant already four months before the appearance of new lesion. The observed increase of T1free was relatively small. MT variables of reactivated lesions were always different from NAWM but showed no characteristic time course.

CONCLUSIONS

Multiparametric MT measurements suggest both a reduction of macromolecular material and a focal increase of free water to occur several months before the appearance of an active lesion. Reduction of the magnetization exchange rate, which may result from primary damage to myelin, appears to be the leading event

[Incidental findings in cardiology. Diagnosing today what can cause illness tomorrow]

Among the anatomical and functional findings in cardiology, congenitally corrected transposition of the major vessels (ventricular inversion), bicuspid aortic valve and prolapse of the mitral valve with simultaneous mitral insufficiency have at least a potential for causing future problems. In such cases, regular cardiological checks or a further diagnostic work-up is to be recommended. The assessment of cardiac sounds can usually be correctly interpreted on the basis of the history, physical examination and auscultation. Among the electrocardiological findings, complete left bundle-branch block and prolongation of the QT segment, mandate clarification of a structural heart condition. Furthermore, in the event of ventricular extrasystoles, right-ventricular cardiomyopathy needs to be excluded. Such isolated conduction disorders as left-anterior fascicular block or right bundle-branch block are of no prognostic significance.

Magnetic resonance diffusion tensor imaging for characterizing diffuse and focal white matter abnormalities in multiple sclerosis

High-resolution diffusion tensor imaging (DTI) was performed in 14 patients with clinically definite multiple sclerosis (MS) and the trace of the diffusion tensor (<D>) and the fractional anisotropy (FA) were determined in normal appearing white matter (NAWM) and in different types of focal MS lesions. A small but significant increase of the <D> in NAWM compared to control white matter ((840 +/- 85) x 10(-6) mm(2)/sec vs. (812 +/- 59) x 10(-6) mm(2)/sec; P < 0.01) was found. In addition, there was a significant decrease in the FA of normal-appearing regions containing well-defined white matter tracts, such as the genu of the internal capsule. In non-acute lesions, the <D> of T(1)-hypointense areas was significantly higher than that of T(1)-isointense lesions ((1198 +/- 248) x 10(-6) mm(2)/sec vs. (1006 +/- 142) x 10(-6) mm(2)/sec; P < 0. 001), and there was a corresponding inverse relation of FA. Diffusion characteristics of active lesions with different enhancement patterns were also significantly different. DTI with a phase navigated interleaved echo planar imaging technique may be used to detect abnormalities of isotropic and anisotropic diffusion in the NAWM and selected fiber tracts of patients with MS throughout the entire brain, and it demonstrates substantial differences between various types of focal lesions.

Diffusion-weighted MR imaging of the spinal cord

Diffusion-weighted MR imaging may increase the sensitivity and specificity of MR imaging for certain pathologic conditions of the spinal cord but is rarely performed because of several technical issues. We therefore tested a novel phase-navigated spin-echo diffusion-weighted interleaved echo-planar imaging sequence in seven healthy volunteers and six patients with intramedullary lesions. We performed diffusion-weighted MR imaging of the spinal cord with high spatial resolution. Different patterns of diffusion abnormalities observed in patient studies support the possible diagnostic impact of diffusion-weighted MR imaging for diseases of the spinal cord.

Expression of Matrix Metalloproteinase-2 and -9 and Their Inhibitors in Peripheral Blood Cells of Patients with Chronic Hepatitis C

Background: To clarify whether circulating matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) can be used as serum markers of fibroproliferation in chronic liver diseases, we studied the expression of MMP-2 and MMP-9 in relation to TIMP-1 and TIMP-2 in peripheral blood mononuclear leukocytes (MNLs) and polymorphonuclear leukocytes (PMLs), and compared this expression to circulating concentrations and hepatic histology in patients with chronic active hepatitis C (CAH).

Methods: Quantitative reverse transcription-PCR/ELISA assays were performed for MMP and TIMP RNA, and corresponding circulating protein concentrations were studied by ELISA in 20 healthy controls, 40 patients with CAH, and 20 patients with hepatitis C-induced cirrhosis (Ci).

Results: MMP-2 mRNA was found almost exclusively in the liver, MMP-9 mRNA in leukocytes. TIMP RNA-equivalents were decreased in MNLs of CAH patients, but neither MMP-9 nor TIMP RNA expression showed any correlation to the extent of inflammation and fibrosis. MMP-2 and TIMP-1 protein concentrations were increased in Ci patients and showed a wide overlap in CAH patients and healthy controls. MMP-9 values were lower in CAH and Ci patients than in healthy controls. TIMP-2 values showed a wide overlap in all three groups. The MMP-2/TIMP-1 and MMP-9/TIMP-1 ratios were lower in Ci patients than in healthy controls; the MMP-2/TIMP-2 and MMP-9/TIMP-2 ratios were not different. Circulating TIMP-1 and the MMP-2/TIMP-1 ratio correlated to the inflammatory activity in liver biopsies, but only the circulating MMP-2/TIMP-1 ratio also correlated with the degree of fibrosis.

Conclusions: Peripheral blood cell expression of MMP-2, MMP-9, and TIMP revealed no correlation with the circulating concentrations of these proteins. Only the circulating MMP-2/TIMP-1 ratio correlated to the histological degree of fibrosis in hepatitis C and should be further evaluated as a progression marker in patients with chronic liver disease.

Expression of matrix metalloproteinase-2 and -9 and their inhibitors in peripheral blood cells of patients with chronic hepatitis C

BACKGROUND

To clarify whether circulating matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) can be used as serum markers of fibroproliferation in chronic liver diseases, we studied the expression of MMP-2 and MMP-9 in relation to TIMP-1 and TIMP-2 in peripheral blood mononuclear leukocytes (MNLs) and polymorphonuclear leukocytes (PMLs), and compared this expression to circulating concentrations and hepatic histology in patients with chronic active hepatitis C (CAH).

METHODS

Quantitative reverse transcription-PCR/ELISA assays were performed for MMP and TIMP RNA, and corresponding circulating protein concentrations were studied by ELISA in 20 healthy controls, 40 patients with CAH, and 20 patients with hepatitis C-induced cirrhosis (Ci).

RESULTS

MMP-2 mRNA was found almost exclusively in the liver, MMP-9 mRNA in leukocytes. TIMP RNA-equivalents were decreased in MNLs of CAH patients, but neither MMP-9 nor TIMP RNA expression showed any correlation to the extent of inflammation and fibrosis. MMP-2 and TIMP-1 protein concentrations were increased in Ci patients and showed a wide overlap in CAH patients and healthy controls. MMP-9 values were lower in CAH and Ci patients than in healthy controls. TIMP-2 values showed a wide overlap in all three groups. The MMP-2/TIMP-1 and MMP-9/TIMP-1 ratios were lower in Ci patients than in healthy controls; the MMP-2/TIMP-2 and MMP-9/TIMP-2 ratios were not different. Circulating TIMP-1 and the MMP-2/TIMP-1 ratio correlated to the inflammatory activity in liver biopsies, but only the circulating MMP-2/TIMP-1 ratio also correlated with the degree of fibrosis.

CONCLUSIONS

Peripheral blood cell expression of MMP-2, MMP-9, and TIMP revealed no correlation with the circulating concentrations of these proteins. Only the circulating MMP-2/TIMP-1 ratio correlated to the histological degree of fibrosis in hepatitis C and should be further evaluated as a progression marker in patients with chronic liver disease.

[Indications of cerebral micro-hemorrhage in MRI. Comparative histological findings and possible clinical significance]

Increased use of gradient echo T2*-weighted gradient echo sequences in magnetic resonance imaging (MRI) of patients suffering from primary ICH called attention to foci of signal loss which were suggested to represent remnants of cerebral microbleeds. In a post mortem correlative MR and histopathological study we provide support for this notion. We found areas of signal loss on gradient echo T2*-weighted sequences in 7 out of 11 brains of patients who had died of intracerebral hematoma. Histopathologically, these areas represented hemosiderin deposits indicating previous extravasation of blood. To provide data about the prevalence of these MRI findings in a healthy elderly population a subgroup of participants of the Austrian Stroke Prevention Study was analyzed. We detected foci of signal loss on gradient echo T2*-weighted sequences in 18 out of 280 volunteers (6.4%). MR-based evidence of previous microbleeds may indicate a potentially higher risk of suffering from intracerebral bleeding which could have therapeutic implications for the treatment of acute stroke and for secondary prevention. This hypothesis will have to be tested in future prospective trials.

Expression of matrix metalloproteinase-9 and its inhibitors in mononuclear blood cells of patients with multiple sclerosis

Inflammatory mononuclear cells invading the nervous system in demyelinating diseases are supposed to be a major source of matrix metalloproteinases which are involved in damaging the blood-brain barrier and facilitating cellular migration through the extracellular matrix. Several studies revealed a crucial role of 92 kDa gelatinase (matrix metalloproteinase-9, MMP-9) in these processes. In this study, we determined MMP-9, TIMP-1 and TIMP-2 (tissue inhibitor of metalloproteinase) mRNA in peripheral blood mononuclear cells of multiple sclerosis (MS) patients by competitive reverse transcription PCR and plasma protein levels by ELISA. In active MS patients, both with relapsing-remitting and chronic progressive disease MMP-9 mRNA and plasma protein levels were significantly increased compared to healthy controls. No significant changes in mRNA expression were found for TIMP-1 and TIMP-2. However, unbound TIMP-2 in plasma was significantly higher in MS patients compared to healthy controls. MMP-9 and TIMP-1 expression was significantly correlated in MS with a significantly higher MMP-9/TIMP-1 ratio in active MS than in healthy controls. These results are in support of an important pathogenic role of MMP-9 activity in MS.

Differential expression of matrix metalloproteinases in bacterial meningitis

Matrix metalloproteinases (MMPs) are implicated in the pathogenesis of various inflammatory diseases of the central nervous system. Evidence is accumulating that gelatinase B (MMP-9) might be involved in the pathogenesis of meningitis, but the spectrum of different MMPs involved in the inflammatory reaction of this disease has not been determined. We investigated the temporal and spatial mRNA expression pattern of gelatinase B in experimental meningococcal meningitis in rats. In contrast to controls, increased mRNA levels with peak values 6 h after injection with menigococci were found in brain specimens of the animals. Elevated MMP-9 mRNA expression was accompanied by enhanced proteolytic activity, as demonstrated by gelatin zymography, and positive immunoreactivity. The mRNA expression pattern of six other MMPs was investigated. Collagenase-3 and stromelysin-1 mRNAs were also found to be upregulated. In contrast, mRNA levels for gelatinase A, matrilysin, stromelysin-2 and stromelysin-3 remained unchanged. As evidenced by significantly increased intracranial pressure and by leakage of intravenously injected Evans blue through the blood vessel walls into the brain parenchyma, the animals injected with meningococci revealed signs of blood-brain barrier disruption. Augmented proteolytic activity of MMP-9 could also be demonstrated in CSF samples obtained from patients with bacterial meningitis, underlining the clinical relevance of our experimental findings. Our data indicate that gelatinase B, collagenase-3 and stromelysin-1 are selectively upregulated in bacterial meningitis and thus may contribute to the pathogenesis of this infectious disease of the central nervous system.