Correlation between Magnetic Resonance Imaging Findings and Pathological Observations in Tumefactive Multiple Sclerosis

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system. Tumefactive MS (TMS) is a subtype of MS characterized by solitary or multiple mass lesions with open-ring enhancement on brain magnetic resonance imaging (MRI). Three TMS cases, diagnosed histopathologically by brain biopsy, that were difficult to distinguish from brain tumors or brain abscesses on MRI are presented. On T2-weighted imaging (T2WI) the lesions were high intensity in the center and periphery, with open-ring contrast enhancement at the periphery; iso- to low intensity areas (“T2 low rim”) were seen in the surrounding region. Histopathological examination revealed the characteristic features of TMS: severe central demyelination and focal necrosis, peripheral neovascularization and perivascular inflammatory cell infiltration, and perifocal edema. On immunochemistry, both the endothelial cells of the neovasculature and the surrounding macrophages in the periphery expressed vascular endothelial growth factor and monocyte chemoattractant protein-1, which mediate inflammation and angioneogenesis and increase vascular permeability. These findings correspond to the T2 low rim co-localizing with the site of gadolinium enhancement on MRI. Thus, the present study clearly demonstrates the correlation between the radiological features and the pathophysiological aspects of TMS, which may contribute to more precise diagnosis of TMS.

Uniaxial cyclic stretch increases glucose uptake into C2C12 myotubes through a signaling pathway independent of insulin-like growth factor I

Insulin-like growth factor I (IGF-I), an autocrine/paracrine growth factor involved in myogenesis, has rapid effects on muscle metabolism. In a manner analogous to insulin and mechanical stimuli such as stretch, IGF-I stimulates glucose transport through recruitment of glucose transporters to surface membranes in skeletal muscles. It is known that IGF-I is secreted from skeletal muscle cells in response to stretch. Therefore, we examined whether IGF-I is involved in the mechanism by which mechanical stretch regulates glucose transport using cultured C2C12 myotubes. IGF-I increased 2-deoxy- D-glucose (2-DG) uptake, and this created an additive effect with mechanical stretch, suggesting that these stimuli enhance glucose transport through different mechanisms. In fact, IGF-I-stimulated 2-DG uptake was not blocked by dantrolene (an inhibitor of Ca (2+)release from sarcoplasmic reticulum), whereas the stretch-stimulated effect was abolished. Conversely, the IGF-I-stimulated 2-DG uptake was prevented by phosphatidylinositol 3-kinase inhibitor wortmannin, which did not prevent the stretch-stimulated 2-DG uptake. In addition, experiments using media conditioned by stretched myotubes indicated that a mechanically induced release of locally acting autocrine/paracrine growth factors was not sufficient for induction of 2-DG uptake. Thus, our results demonstrate that mechanical stretch signaling for glucose transport is independent of the mechanism through which IGF-I increases this transport.

Long-term interleukin-1alpha treatment inhibits insulin signaling via IL-6 production and SOCS3 expression in 3T3-L1 adipocytes

Proinflammatory cytokines are well-known to inhibit insulin signaling to result in insulin resistance. IL-1alpha is also one of the proinflammatory cytokines, but the mechanism of how IL-1alpha induces insulin resistance remains unclear. We have now examined the effects of IL-1alpha on insulin signaling in 3T3-L1 adipocytes. Prolonged IL-1alpha treatment for 12 to 24 hours partially decreased the protein levels as well as the insulin-stimulated tyrosine phosphorylation of IRS-1 and Akt phosphorylation. mRNA for SOCS3, an endogenous inhibitor of insulin signaling, was dramatically augmented 4 hours after IL-1alpha treatment. Concomitantly, the level of IL-6 in the medium and STAT3 phosphorylation were increased by the prolonged IL-1alpha treatment. Addition of anti-IL-6 neutralizing antibody to the medium or overexpression of dominant-negative STAT3 decreased the IL-1alpha-stimulated STAT3 activation and SOCS3 induction, and ameliorated insulin signaling. These results suggest that the IL-1alpha-mediated deterioration of insulin signaling is largely due to the IL-6 production and SOCS3 induction in 3T3-L1 adipocytes.

Isolated limb sensory disturbance accompanied with sudden deafness from vertebral artery dissection: a case report

A 52-year-old male presented with right sudden deafness and left isolated limb sensory disturbance following posterior neck pain. An examination revealed a mild degree of right sensory neural hearing loss and decreased pain and thermal sensation in the left side below the L3 level. Brain MRI showed a small lesion in the midlateral portion of the right middle-rostral medulla. The combination of the image findings suggests a right lateral medullary infarction caused by a vertebral artery (VA) dissection. In our case, the fibers carrying the modalities of the lateral spinothalamic tract restricted to below the L3 level, sparing other sensations, suggest a selective involvement. This finding suggests that sensory dermatomal representation in the modality may be preserved at least up to the level of the medulla oblongata. Moreover, in our case, the small emboli originating from the dissected VA possibly caused a small selective cochlear infarction. This type of embolism may give rise to various combinations of symptoms depending on the branches involved. For patients with an acute onset of headache or neck pain who present with isolated limb sensory disturbance accompanied by sudden deafness, even without the classical brainstem signs, a VA dissection and medullary infarction should therefore be considered.

Interferon Beta-1b may reverse axonal dysfunction in multiple sclerosis

Progression of the disability of multiple sclerosis (MS) is thought to be related to axonal damage that is seen even in normal appearing white matter (NAWM) of patients' brains. Interferon beta (IFNβ) treatment for MS reduces the frequency of clinical exacerbations and the appearance of new inflammatory demyelinating lesions on magnetic resonance imaging (MRI). However, the effect of IFNβ treatment on axonal damage in MS is not known. The present study aimed to assess the effect of IFNβ on axonal function by comparing the data from localised single voxel proton MR spectroscopy (MRS) performed on eight MS patients given IFNβ-1b treatment and 11 untreated patients. Brain MRI and MRS were performed before the initiation of IFNβ-1b treatment and 24 months after treatment initiation. Levels of N-acetylaspartate (NAA), choline-containing compounds (Cho) and creatine (Cr) were calculated as the areas under their peaks shown on MRS and the ratios of NAA/Cr and Cho/Cr were calculated. In the patients treated with IFNβ-1b there was a significant increase in the ratio of NAA/Cr in NAWM (p=0.028) at 24 months after the initiation of treatment. In contrast, there was no significant change in the NAA/Cr ratio in the untreated patients. These results suggest that IFNβ-1b treatment might recover axonal function in NAWM of MS patients.

Effects of delta-opioid receptor stimulation and inhibition on hippocampal survival in a rat model of forebrain ischaemia

BACKGROUND

It has been reported that delta-opioid (DOP) receptor agonists may be neuroprotective in the central nervous system. However, the DOP agonist [d-Ala(2), d-Leu(5)]enkephalin (DADLE) does not produce neuroprotection in severe forebrain ischaemia. The aim of this study was to examine the effects of DADLE on hippocampal neurone survival against less severe forebrain ischaemia.

METHODS

Intraperitoneal injection of DADLE (0 or 16 mg kg(-1)) in male Sprague-Dawley rats was performed 30 min before ischaemia. Severe (10 min), moderate (8 min), or mild (6 min) forebrain ischaemia was produced by bilateral carotid occlusion combined with hypotension (35 mm Hg) under isoflurane (1.5%) anaesthesia. Naltrindole (10 mg kg(-1)) (DOP antagonist) was administered 30 min before DADLE in order to confirm DOP receptor activation in the neuroprotective efficacy of DADLE. Naltrindole alone was also administered 30 min before ischaemia to examine endogenous DOP agonism as a self-protecting mechanism against ischaemia. All animals were evaluated neurologically and histologically after a 1 week recovery period.

RESULTS

DADLE improved neurone survival in hippocampal CA3 and dentate gyrus (DG) sectors. CA1 neurones were not protected against moderate and mild ischaemia. Naltrindole abolished DADLE neuroprotection in the CA3 and DG after both moderate and mild ischaemia. Interestingly, regardless of co-administration of DADLE, naltrindole significantly worsened neuronal injury in the CA1 region after mild ischaemia.

CONCLUSIONS

These results suggest that DADLE provides limited neuroprotection to relatively ischaemia-resistant regions but not to selectively vulnerable regions. This was probably mediated by DOP stimulation. Pre-ischaemic treatment with a DOP antagonist, regardless of co-administration of DADLE, worsened neuronal damage at the selectively vulnerable regions only after mild forebrain ischaemia. These data suggest that DOP activation with endogenous DOP ligand may be involved in self-protecting ischaemia-sensitive regions of the brain.

Reduced expression of inducible gelatinase B/matrix metalloproteinase-9 in monocytes from patients with myelodysplastic syndrome: Correlation of inducible levels with the percentage of cytogenetically marked cells and with marrow cellularity

Regulatory molecules produced by stromal cells are often membrane bound until cleaved by matrix metalloproteinases (MMPs); cleavage can either activate or inactivate regulatory functions. We report here that marrow stromal cells induce the expression of MMP-9 in monocytes. Induction was contact independent and could be reproduced with recombinant MCP-1/CCL2, whereas IL-6, M-CSF, G-CSF, GM-CSF, IL-8/CXCL8, SDF-1/CXCL12, and MGSA/CXCL1 did not have this effect. Stroma-induced levels of MMP-9 in the monocyte population from healthy donors were relatively consistent, whereas induced levels varied significantly (P < .001) in the CD14+ population from 27 patients with myelodysplastic syndrome (MDS). In patients with a clonal chromosomal marker, the level of inducible MMP-9 expression in the monocyte population was inversely correlated with the percentage of marker-positive cells (n = 11, P = .01), suggesting that the ability to induce MMP-9 may be compromised in clonally derived monocytes. The inducible levels of MMP-9 were also inversely correlated with marrow cellularity observed in biopsies from MDS patients (P < .001). We conclude that monocytes can express MMP-9 in response to stromal factors and that this response may be significantly decreased in MDS-derived monocytes.

Monocyte-derived CXCL7 peptides in the marrow microenvironment

The marrow microenvironment consists of several different interacting cell types, including hematopoietic-derived monocyte/macrophages and nonhematopoietic-derived stromal cells. Gene-expression profiles of stromal cells and monocytes cultured together differ from those of each population alone. Here, we report that CXCL7 gene expression, previously described as limited to the megakaryocyte lineage, is expressed by monocytes cocultured with stromal cells. CXCL7 gene expression was confirmed by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), and secretion of protein was detected by enzyme-linked immunosorbent assay (ELISA) and Western blot. At least 2 stromal-derived activities, one yet to be identified, were required for optimal expression of CXCL7 by monocytes. NAP-2, the shortest form of CXCL7 detected in the coculture media, was confirmed to decrease the size and number of CFU-Meg colonies. The propeptide LDGF, previously reported to be mitogenic for fibroblasts, was not secreted by stimulated monocytes. The recombinant form of LDGF produced in a prokaryotic expression system did not have biologic activity in our hands. The monocytic source of CXCL7 was also detected by immunohistochemistry in normal bone marrow biopsies, indicating an in vivo function. We conclude that stromal-stimulated monocytes can serve as an additional source for CXCL7 peptides in the microenvironment and may contribute to the local regulation of megakaryocytopoiesis.

Hippocampal synapsin I, growth-associated protein-43, and microtubule-associated protein-2 immunoreactivity in learned helplessness rats and antidepressant-treated rats

Learned helplessness rats are thought to be an animal model of depression. To study the role of synapse plasticity in depression, we examined the effects of learned helplessness and antidepressant treatments on synapsin I (a marker of presynaptic terminals), growth-associated protein-43 (GAP-43; a marker of growth cones), and microtubule-associated protein-2 (MAP-2; a marker of dendrites) in the hippocampus by immunolabeling. (1) Learned helplessness rats showed significant increases in the expression of synapsin I two days after the attainment of learned helplessness, and significant decreases in the protein expression eight days after the achievement of learned helplessness. Subchronic treatment of naïve rats with imipramine or fluvoxamine significantly decreased the expression of synapsin I. (2) Learned helplessness increased the expression of GAP-43 two days and eight days after learned helplessness training. Subchronic treatment of naïve rats with fluvoxamine but not imipramine showed a tendency to decrease the expression of synapsin I. (3) Learned helplessness rats showed increased expression of MAP-2 eight days after the attainment of learned helplessness. Naïve rats subchronically treated with imipramine showed a tendency toward increased expression of MAP-2, but those treated with fluvoxamine did not. These results indicate that the neuroplasticity-related proteins synapsin I, GAP-43, and MAP-2 may play a role in the pathophysiology of depression and the mechanisms of antidepressants.

Evaluating the effects of spatial frequency on migraines by using pattern-reversal visual evoked potentials

OBJECTIVE

To clarify the effects of contrast and spatial frequency in patients with migraine by means of pattern-reversal visual evoked potentials (PVEPs).

METHODS

PVEPs were obtained from 14 patients who had migraine without aura (MO), 11 patients who had migraine with aura (MA), and 25 age-matched, healthy controls (CO). PVEPs were binocularly recorded with a reversal rate of 1Hz (2 reversal/s) at 3 spatial frequencies (0.5, 1.0 and 4.0 cpd) at high (98%), medium (83%) and low (29%) contrast. N75, P100 and N135 latency and the amplitudes of P50-N75, N75-P100 and P100-N135 were analyzed.

RESULTS

Increased amplitude of PVEPs in patients with migraines were revealed at 3 different spatial frequencies in all components. The MO and the MA showed increased amplitudes mostly in high contrasts (98%). These findings were detected more at a high spatial frequency (4.0 cpd) than at a low spatial frequency (0.5 cpd). Increased amplitude with prolonged latency of N135 were found both in MO and MA at 4.0 cpd.

CONCLUSIONS

We conclude that pattern stimuli of high contrasts may be particularly effective in uncovering abnormal cortical reactivity which may be modified in the primary and secondary visual cortex in the interictal state of migraine.

SIGNIFICANCE

These findings indicate that there is abnormal visual cortex processing in patients with migraine.

Expression and function of IL-7 receptors in marrow stromal cells

IL-7 was first isolated in 1988, when its role in early B lymphocyte development was noted [1-3]. It soon became apparent that IL-7 is a "stromal cytokine" produced by a variety of stromal tissues including those in bone marrow and thymus [4-10]. The production of IL-7 by bone marrow stromal cells is thought to be essential for early B lymphocyte development at least in the murine model, and secreted IL-7 from extra thymic sources including bone marrow is postulated to play a critical role in post-thymic T cell homeostasis [11-15]. Although IL-7 was thought to have effects mostly within the lymphoid populations, the demonstration of IL-7 receptors in non-lymphoid cells including primary marrow stromal cells has challenged this paradigm [15]. In this report, we present data showing that functional IL-7 receptors are expressed by marrow stroma and that IL-7 mediated signaling through this receptor is distinct from that mediated by IL-7 receptors expressed on lymphoid cells.

Ileocolonic lymphomas: a series of 16 cases

BACKGROUND

Colonoscopic and clinical differences between primary ileocolonic mucosa-associated lymphoid tissue (MALT) lymphoma and mantle cell lymphoma (MCL) have not been defined.

METHODS

We reviewed colonoscopic and clinical features in eight patients with primary MALT lymphoma and eight patients with MCL in the terminal ileum and/or colorectum. All cases were examined for CD5 and/or cyclin D1 expression.

RESULTS

Endoscopic features of MALT lymphoma were characterized as protrusions that were covered with normal-appearing mucosa with or without ulceration. The gross appearances of MALT lymphomas were categorized as solitary (4 patients), multiple (3 patients), and multiple lymphomatous polyposis (MLP) (1 patient). The gross features of MCL at endoscopy were categorized as multiple protrusions (2 patients), and MLP (6 patients). The clinical stages of patients with MCL were more advanced than in patients with MALT lymphoma.

CONCLUSIONS

Solitary or multiple protrusions at an early clinical stage is the most common presentation pattern of patients with MALT lymphoma, but an MLP appearance at an early stage is also possible. On the other hand, MLP appearance with an advanced clinical stage is the main presentation pattern in patients with MCL, although multiple protrusions with an early clinical stage is also possible. Histological and immunohistochemical investigation including that of cyclin D1 and CD5 expression is essential to make the final diagnosis.

Comparison of changes in jugular venous bulb oxygen saturation and cerebral oxygen saturation during variations of haemoglobin concentration under propofol and sevoflurane anaesthesia

BACKGROUND

A severe reduction in haemoglobin concentration can lead to a decrease in jugular venous bulb oxygen saturation (Sj(O(2))). However, recent evidences suggests that cerebral oxygen saturation (Sc(O(2))) measured by near infrared spectroscopy decreased during even mild haemodilution. We therefore tested the hypothesis that the changes in Sc(O(2)) may not be parallel to those in Sj(O(2)) during haemodilution. In addition, as cerebral oxygen balance during the operation can vary depending on the anaesthetics used, the changes in Sj(O(2)) and Sc(O(2)) during haemodilution were compared between patients under propofol and isoflurane/nitrous oxide anaesthesia.

METHODS

Forty-two patients with pre-donated autologous blood were randomly assigned to receive propofol (Group P) or sevoflurane/nitrous oxide (Group S) anaesthesia. A fibreoptic catheter was placed in the jugular bulb to measure Sj(O(2)). A cerebral oximeter, INVOS 4100S was used to monitor Sc(O(2)). Arterial and jugular bulb blood samples were drawn simultaneously at: (i) 10 min after the start of operation, (ii) after 400 ml of blood loss, (iii) after 800 ml of blood loss, (iv) just before the transfusion of pre-donated autologous blood, and (v) after 400 ml transfusion.

RESULTS

Mean (sd) control values of Sj(O(2)) in Group P were significantly lower than those in Group S (55 (8)% vs 71 (10)%, respectively; P<0.05), whereas there was no significant difference in control values of Sc(O(2)) between the two groups. During the operation, haemoglobin (Hb) concentrations significantly deceased in the both groups compared with control values (from 9.8 to 7.6 g dl(-1) in Group P and from 9.9 to 8.0 g dl(-1) in Group S). During a reduction in Hb concentration, Sj(O(2)) values remained unchanged in both groups, whereas Sc(O(2)) values significantly decreased in both groups (from 57 to 51% in Group P and from 59 to 52% in Group S).

CONCLUSION

The results indicated that, although the changes in Sj(O(2)) and Sc(O(2)) during a reduction in haemoglobin concentration were similar under propofol and sevoflurane/nitrous oxide anaesthesia, the changes in Sc(O(2)) were not parallel to those in Sj(O(2)). The discrepancy of the results in Sj(O(2)) and Sc(O(2)) may make the interpretation of their values difficult during haemodilution.

Pregnenolone and dehydroepiandrosterone administration in neonatal rats alters the immunoreactivity of hippocampal synapsin I, neuropeptide Y and glial fibrillary acidic protein at post-puberty

It is well documented that neurosteroids administered during the neonatal period influence the development of several brain systems. In our previous study, pregnenolone administered to rats during the neonatal period altered adenosinergic and dopaminergic functions in the striatum and cerebral cortex. The present study examined the effects of the treatment with pregnenolone and dehydroepiandrosterone (DHEA) from the postnatal day (P) 3-P7 on synapsin I (a marker for presynaptic terminals) and glial fibrillary acidic protein (GFAP: a marker for astroglia) levels in the hippocampus of Sprague-Dawley rats at 3 and 7 weeks of age. In addition, neuropeptide Y and dynorphin A immunoreactivity was measured. The administration of pregnenolone and DHEA to neonatal rats significantly altered the expression of synapsin I in the dentate gyrus and CA3 region at post-puberty but not at pre-puberty. A significantly greater expression of GFAP-immunoreactive astrocytes or processes was demonstrated in the pregnenolone- and DHEA-treated groups at both pre-puberty and post-puberty. A significant increase in the number and size of GFAP-immunoreactive astrocytes and in the extension of arborization was seen in the overall hippocampus. The number of neuropeptide Y-positive cells in the hilus region was also significantly increased in the neurosteroid-treated group at post-puberty. No differences were detected in dynorphin A immunoreactivity among the experimental groups. These results of this study suggest that pregnenolone and DHEA play an important role in the development of hippocampus.