视神经脊髓炎患者33例脑部磁共振分析

目的 探讨视神经脊髓炎(neuromyelitis optica,NMO)患者脑部MRI影像学表现.方法 收集满足最新NMO诊断标准且脑部MRI表现不符合多发性硬化诊断标准的患者33例,均行脑部和脊髓MRI检查,分析其MRI影像学特点.结果 33例NMO中,脑部正常表现者5例(15.2%),异常表现28例(84.8%),其中脑内实质有明确病灶22例(66.7%),另6例(18.2%)脑内虽未见明确病灶,但深部脑白质显示了肉眼可视的对称性弥漫性脱髓鞘高信号影.22例明确病灶中,15例病灶数≥2个,7例为单个病灶.幕上近皮质、皮质下和深部脑白质区的点状非特异性病灶最多,少数为非典型的斑片状融合病灶.幕下脑干是易受累的部位(14/33,42.4%),特别是延髓(7/33,21.2%).结论 NMO患者出现脑内异常较为常见,有脑部的异常不能排除NMO的诊断.认识NMO脑内病灶对完善NMO诊断标准有帮助.     

多发性硬化的MRI特征

目的 探讨多发性硬化(MS)患者脑及脊髓的MRI特征.方法 回顾性分析110例临床确诊的MS患者的MRI检查资料.结果 MS患者脑部病灶以侧脑室旁白质多见(55.8%),其次是额叶深部白质(54.7%)、顶叶深部白质(44.2%)、脑干(25.6%)、基底节(23.3%)、丘脑(11.6%)等,灰质也可受累;病灶大小不一,形态可为斑片状、斑点状、圆形、类圆形.脊髓病灶以颈、胸髓多见,分别占75.0%和68.8%,形态可为斑片状、条片状、类圆形,脊髓灰白质可同时受累,10.0%的患者出现脊髓形态改变,如增粗、萎缩.MS患者脑及脊髓内病灶在影像学上因病程不同可表现为长T1、长T2或等T1、长T2信号.结论 MS的MRI特点主要是以脑和脊髓白质出现多个大小、形状不同的病灶.     

Magnetic resonance imaging of Asians with multiple sclerosis was similar to that of the West

Magnetic resonance imaging (MRI) of the brain is the most important paraclinical diagnostic test in multiple sclerosis (MS). The appearance of MRI in Asians with MS is not well defined. We retrospectively surveyed the first brain and spinal cord MRI in patients diagnosed to have MS, according to Poser's criteria in seven regions throughout Asia to define the MRI changes among Asians with MS. There were 101 patients with first brain, and 86 with first spinal cord MRI, 66 of whom had both. The brain MRI showed a mean of 17 lesions per patient in T2 weighted images, mostly asymptomatic. Almost all the lesions were in the white matter, particularly in the juxtacortical, deep and periventricular white matter. A third of the lesions were greater than 5 mm, 14% enhanced with gadolinium. There were more supratentorial than infratentorial lesions at a ratio of 7.5: 1. Ninety five percent of the spinal cord lesions were in cervical and thoracic regions, 34% enhanced with gadolinium. The lesions extended over a mean of 3.6 +/- 3.3 vertebral bodies in length. Fifty (50%) of the brain and 54 (63%) of the spinal MRI patients had the optic-spinal form of MS. The MRI of the optic-spinal and classical groups of patients were similar in appearance and distribution, except that the optic-spinal MS patients have fewer brain but longer and more severe spinal cord lesions. In conclusion, the brain and spinal cord MRI of Asian patients with MS was similar to that of the West, although, in this study, Asian MS patients had larger spinal cord lesions.     

Significance of gray matter brain lesions in multiple sclerosis and neuromyelitis optica

Multiple sclerosis (MS) and neuromyelitis optica (NMO) are the two main autoimmune diseases of the CNS. In patients with NMO, the target antigen is aquaporin‐4 (AQP4), the most abundant water channel protein in the CNS. AQP4 is mainly expressed on astrocytic endfoot processes at the blood‐brain barrier and in subpial and subendymal regions. MS and NMO are distinct diseases, but they have some common clinical features: both have long been considered autoimmune diseases that primarily affect the white matter (WM). However, because WM demyelination by itself cannot explain the full extent of the clinical disabilities, including cognitive decline in patients with MS and NMO, renewed interest in gray matter (GM) pathology in MS and NMO is emerging. Important hallmarks of WM and GM lesions in MS and NMO may differentially influence neuronal degeneration and demyelination in the brain and spinal cord, given different detrimental effects, including cytokine diffusion, disruption of water homeostasis associated with or without AQP4 (the target antigen in NMO) dynamics, or other unidentified mechanisms. An increase in knowledge of the structure of GM and WM lesions in MS and NMO will result in more targeted therapeutic approaches to these two diseases.     

Spectrum disorder of neuromyelitis optica in a patient presenting with intractable vomiting and hiccups,transverse myelitis and acute encephalopathy

Optic neuropathy and transverse myelitis (TM) are common symptoms of multiple sclerosis (MS) but may also be seen in association with the antibody-mediated autoimmune disorder, neuromyelitis optica (NMO). We report a female patient presenting with intractable vomiting and hiccups and TM shortly followed by an acute encephalopathy, most likely due to NMO spectrum disorder. Serum and cerebrospinal fluid NMO antibodies were negative. Serial MRI abnormalities included longitudinally extensive TM of the cervical cord, focal T2-weighted hyperintensity of the area postrema and lesions in both thalami and the hypothalamus. Clinical and MRI involvement of these brain regions, which have high aquaporin expression, in conjunction with a spinal lesion extending over three vertebral segments strongly favoured a diagnosis of NMO. She required several courses of intravenous methylprednisolone and plasmapheresis before receiving intravenous rituximab therapy. NMO spectrum disorder should be considered in the differential diagnosis of atypical central nervous system presentations such as intractable vomiting and hiccups and acute encephalopathy. Recognition of this syndrome has significant implications as its treatment and prognosis differs from MS.     

Brain magnetic resonance imaging abnormalities in neuromyelitis optica

Objective – Brain abnormalities in neuromyelitis optica (NMO) attracted much attention. Our study was to identify the brain magnetic resonance imaging (MRI) abnormalities in Chinese NMO patients. Methods – Patients who fulfilled the latest diagnostic criteria of NMO proposed by Wingerchuk et al. [Neurology 66 (2006) 1485] and whose brain MRI did not meet the multiple sclerosis (MS) criteria of McDonald et al. [Ann Neurol 50 (2001) 121] were selected to perform MRI scanning of the brain, spinal cord and optic nerves. Results – Twenty‐eight of 33 patients (84.8%) had abnormal MRI findings. Twenty‐two patients (66.7%) presented with well‐defined brain parenchymal lesions and the other six patients (18.2%) with macroscopic symmetrical diffuse hyperintensities in deep white matter. Fifteen of 22 patients had more than one lesion (≥2 lesions) and the other seven patients had single lesion. In the supratentorium, most lesions were punctate or small round dot and non‐specific in juxtacortical, subcortical and deep white matter regions, a few were patchy atypical confluent lesions. Brainstem was easily involved (14/33, 42.4%) especially in medulla (7/33, 21.2%). Conclusions – This study demonstrates the characteristics of brain MRI abnormalities in Chinese NMO patients, which are helpful to the revision of diagnostic criteria for NMO.     

原发性干燥综合征中枢神经系统损害八例临床分析

目的探讨原发性干燥综合征的中枢神经系统损害的临床表现、MRI特点、治疗方法。 方法 回顾性分析漳州市福建医科大学附属漳州市医院确诊的8例原发性干燥综合征合并中枢神经系统损害的临床表现、MRI特点。 结果临床可表现为延髓背外侧综合征、肢体无力、智能改变,可类似多发性硬化、视神经脊髓炎,视神经较经常累及;MRI检查示5例出现脊髓损害：病变部位以颈胸髓为主,颈髓2例,胸髓2例,1例同时累及颈髓和胸髓,病灶可大片状、散在斑片状,可轻度、明显强化或不强化,5例出现颅内损害：病变部位可见于延髓背外侧、丘脑、海马、中脑导水管、第四脑室旁、侧脑室旁,可表现为皮质下及脑室旁白质多发小缺血灶,可类似韦尼克脑病,l例出现颈动脉夹层,7例使用了激素后病情有一定改善。 结论原发性干燥综合征中枢神经系统损害的症状、体征及影像学表现多种多样。     

Seropositive neuromyelitis optica spectrum disorder in Emirati patients: A case series

ObjectiveTo describe clinical and radiological characteristics of seropositive neuromyelitis optica (NMO) in Emirati patients. While epidemiology of seropositive NMO in Abu Dhabi has been reported in a previous paper, its clinical and MRI profiles among Emirati patients have not been previously fully investigated.MethodsIn our case series, we describe clinical and MRI characteristics of 5 Emirati patients with NMO, consecutively admitted at Cleveland Clinic Abu Dhabi, a major tertiary hospital in Abu Dhabi, United Arab Emirates.ResultsPatients were all females, mean age of onset (SD) was 41 (11) years, and 67% had autoimmune comorbidities. Most patients initially presented with acute myelitis (80%) while 20% got optic neuritis. Mean (SD) number of further relapses after onset was 3 (1) and mean (SD) disease duration was 12 (11) years. At MRI, apparent longitudinal extensive transverse myelitis was present in all patients affecting mostly the central gray matter of the cervical cord but extending as well to the thoracic portion. Furthermore, seropositive NMO related brain lesions were also observed.ConclusionsOur work provides valuable information regarding seropositive NMO with the potential to increase recognition of this disorder in Abu Dhabi and confirms NMO findings described in the other populations with this disorder. Further research is needed to advance clinical and MRI characterization of seronegative NMO in the region.     

Characterization of brain lesions in a mouse model of progressive multiple sclerosis

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system characterized by damage to the neuronal myelin sheath, which results in different levels of muscle paralysis that can lead to neuronal death. In most MS mouse models, the neurologic damage mostly affects the spinal cord with limited damage to the brain, which cannot be monitored by magnetic resonance imaging (MRI) as used for humans. We show that immunization of non-obese diabetic (NOD) mice with myelin oligodendrocyte glycoprotein peptide 35-55 leads to the development of relapsing-remitting stages, evident from days 20 to 70, which then develops into a chronic progressive stage. This cycle is similar to MS stages found in humans. Brain MRI gadolinium-enhanced T1-weighted image analysis showed an increased blood-brain barrier permeability in brain gray and white matter specific to the corpus callosum, fimbria, and internal capsule as found in humans. MRI fractional anisotropy analysis showed demyelination and axonal damage in identical regions. Immunohistologic analysis supported the MRI data. No evidence of brain lesions was found in a common model of MS using C57BL/6 mice. We suggest that an increase in astrocyte toxicity in experimental autoimmune encephalomyelitis-induced NOD mice may be linked to brain lesion development. We suggest using NOD mice as a suitable model for studying MS using MRI methods toward future diagnostic and drug development.     

引起顽固性呃逆、呕吐的视神经脊髓炎的临床表现和影像学研究

目的 探讨引起顽固性呃逆、呕吐(IHN)的视神经脊髓炎(NMO)患者的临床表现和脑干、脊髓MRI特点.方法 收集中山大学附属第三医院神经科17例NMO患者的临床资料,对其中8例合并IHN的NMO患者临床表现及MRI特点进行分析.结果 IHN在NMO患者中常见,本组17例NMO中有8例合并IHN,临床上表现为IHN、复视、眼球震颤,其中6例表现有线样延髓征(LML)或线样延髓脊髓征(LMSL).脊髓纵向MRI显示病灶常常大于3个椎体节段,且以脊髓中央管为中心;轴位脊髓MRI表现为部分性或横贯性,以脊髓的后角或侧角为主,前角受累较少. 结论 引起IHN的NMO临床上多伴有复视和眼球震颤,延髓脊髓MRI常常可见LML或LMSL征,而且病灶以脊髓中央管为中心,后角或侧角受累为主,这些可与多发性硬化相鉴别.     

Assessment of normal-appearing white and gray matter in patients with primary progressive multiple sclerosis: a diffusion-tensor magnetic resonance imaging study

BACKGROUND: Diffusion-tensor magnetic resonance imaging is sensitive to the more destructive aspects of multiple sclerosis (MS) evolution occurring outside and within T2-visible lesions and, as a consequence, holds promise for providing a more complete picture of primary progressive (PP) MS-related tissue damage than conventional magnetic resonance imaging. OBJECTIVE: To improve our understanding of PPMS by assessing the extent of occult pathological features in the normal-appearing white and gray matter of the brain using diffusion-tensor magnetic resonance imaging. METHODS: Ninety-six patients with PPMS, 47 patients with secondary progressive (SP) MS, and 44 healthy control subjects were studied. T2-hyperintense and T1-hypointense lesion volumes were calculated, and the volume of the whole brain tissue was measured. Diffusion-tensor magnetic resonance imaging scans were postprocessed and analyzed to obtain the mean diffusivity and fractional anisotropy histograms from the brain and from the normal-appearing white and gray matter in isolation. RESULTS: The mean T2-hyperintense and T1-hypointense lesion volumes were lower in patients with PPMS than in patients with SPMS, while the mean absolute brain volumes were similar in the 2 groups. The average lesion diffusivity was significantly higher in patients with SPMS than in patients with PPMS (P<.001). Histogram-derived metrics of the brain tissue and normal-appearing white and gray matter were significantly different between patients with PPMS and healthy subjects (range, P =.004 to <.001). Average diffusivity values were significantly higher in patients with SPMS than in patients with PPMS for all the tissues studied (range, P =.001 to <.001). Fractional anisotropy histogram-derived quantities did not significantly differ between the 2 patient groups (range, P =.94 to.03). CONCLUSION: This study confirms that, in patients with PPMS, normal-appearing white and gray matter are not spared by disease-related pathological processes, although they are affected to a lesser degree than in patients with SPMS.     

The relationship between lesion and normal appearing brain tissue abnormalities in early relapsing remitting multiple sclerosis

Background In multiple sclerosis (MS), pathological changes have been found both in macroscopic lesions and normal appearing tissue. Magnetisation transfer ratio (MTR) and T1 relaxation time are abnormal in normal appearing tissues in established MS. This study used these MR techniques in early MS to study normal appearing tissues and lesions. The purpose was to determine whether abnormalities are already detectable in normal appearing tissues in early MS, and if so how they correlate with lesion characteristics. Methods Twenty two patients with early relapsing remitting (RR) MS (median disease duration 2 years, range 7 months–3 years) and 11 age-matched controls were studied. MTR and T1 relaxation times were measured in 9 regions of normal appearing white matter (NAWM) and 7 of normal appearing grey matter (NAGM). Gadolinium enhancing, T1-hypointense and T2 lesion loads were measured in all patients. Results When all regions were combined, there was a significant difference between patient and control NAWM for both T1 and MTR; T1 was abnormal in 6/9 and MTR in 3/9 NAWM regions. Global assessment of NAGM revealed a significant difference between patients and controls for T1 but not for MTR; T1 was significantly abnormal only in frontal NAGM. There was no significant correlation between NAWM T1 or MTR and any of the lesion load measurements. Conclusions This study reveals quantitative MR abnormalities in both NAWM and NAGM in early RR MS, with more extensive changes in the former. The lack of correlation between NAWM and lesion abnormalities suggests that they have developed by at least partly independent mechanisms. T1 may be more sensitive than MTR in detecting subtle pathological changes in NAWM and NAGM. Received: 3 April 2001, Received in revised form: 15 June 2001, Accepted: 18 June 2001     

An autopsy case with subacute spinal cord disease showing progressive paraplegia]

We report a 72-year-old woman who died of respitory failure. History included onset of diabetes mellitus at the age of 67 years and hypertension at the age of 72 years. The patient had been in good health otherwise until 2000, when she had onset of numbness or tingling of the bilateral lower limbs. On December 3, 2000, she was admitted to a hospital in the vicinity of her home because of the above-mentioned complaints. Neurological examinations revealed progressive paraplegia. Symptoms and signs suggested Guillain-Barré syndrome. Examinations of cerebrospinal fluids revealed cell count of 338/3 (mono 72%, poly 18%) and protein value of 100 mg/dl. Later the patient course deteriorated. On December 15, 2000, she was admitted to Hakujikai Memorial Hospital for the second time. Ten days later, MRI examination showed diffuse swelling of the spinal cord from the cervical (C 3/4) level to the thoracic level. Gd-enhanced T 1-weighted MRI performed 22 days later showed a partially enhanced lesion at the thoracic (Th 5/6) level of the spinal cord. The patient was treated with steroid therapy (methylprednisolone 500 mg/dl). She died of respiratory failure on January 6, 2001. The patient was presented in a neurological CPC. Neurological and imaging findings suggested a transverse myelopathy. However, there were several points in this case that were unusual for a typical transverse myelopathy, such as total sensory loss below spinal segments of thoracic level (Th 5) and motor weakness of the upper limbs of upper segment of the same level. A clinical neurologist concluded that the patient had subacute transverse myelopathy with fused multiple pathy pathologic lesions. We discussed whether this case was a transverse myelopathy or multiple sclerosis. Post mortem examination revealed acute necrotic myelopathy affecting the spinal cord from the second cervical to the tenth thoracic vertebrae, with conspicuous infiltration of CD 68-positive macrophages involving both gray and white matter, partially necrotic associated with scattered UCHL-1 dominants lymphocytic infiltration of T cells around vessels. There were relatively older lesions with demyelinating features in the spinal roots that were particularly dominant in the anterior roots. No demyelinated plaques in the optic chiasm, tracts and nerves, or in the cerebero-cerebellar white matter were found. Systemic pathological diagnosis was lung edema with fresh hemorrhage, pancreatic atrophy consistent with diabetes mellitus and choleductlithiasis.     

Progressive gray matter damage in patients with relapsing-remitting multiple sclerosis: a longitudinal diffusion tensor magnetic resonance imaging study

BACKGROUND: Diffusion tensor magnetic resonance imaging (DT MRI) has the potential to provide in vivo information about tissue microstructure. In multiple sclerosis (MS), DT MRI has disclosed the presence of occult structural damage in the normal-appearing brain tissues. OBJECTIVE: To investigate whether DT MRI is sensitive to longitudinal changes of brain damage that may occur beyond the resolution of T2-weighted images in patients with relapsing-remitting MS. DESIGN: Twenty-six untreated patients with relapsing-remitting MS were followed up for 18 months. Dual-echo, DT and postcontrast T1-weighted MRIs of the brain were obtained at baseline and then every 3 months. Mean diffusivity (D) histograms of normal-appearing gray (GM) and white matter were produced. Total T2-hyperintense and T1-hypointense lesion volumes; normalized whole brain tissue, GM, and white matter volumes; percentage brain volume change between the study entry and exit images; average lesion D; and fractional anisotropy were also calculated. RESULTS: During the study period, a significant decrease of normalized whole brain tissue, average lesion fractional anisotropy and normal-appearing GM D histogram peak height, and a significant increase of average normal-appearing GM D and T2-hyperintense lesion volumes were observed. Changes of normal-appearing GM diffusivity were independent of the concomitant changes of normalized whole brain tissue and GM volumes. CONCLUSIONS: The DT MRI findings show progressive microstructural changes in the normal-appearing GM of patients with untreated relapsing-remitting MS. Such changes do not reflect a concomitant development of brain atrophy and confirm the importance of GM pathology in MS.     

Long spinal cord lesions in a patient with pathologically proven multiple sclerosis

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system. We report the case of a 50-year-old man who presented with progressive gait ataxia. Brain magnetic resonance imaging (MRI) on fluid-attenuated inversion recovery revealed a hyperintense lesion in the right temporal white matter. The spinal cord showed a long hyperintense lesion between the vertebral levels C6 and L1 on T2-weighted MRI. Biopsied tissues from the brain lesion demonstrated features of inflammatory demyelination with preservation of astrocytes, consistent with typical MS. This is the first reported case of pathologically proven MS with longitudinally extensive spinal cord lesions.     

MRI T2 hypointensity of the dentate nucleus is related to ambulatory impairment in multiple sclerosis

OBJECTIVES: MRI T2 hypointensity in multiple sclerosis (MS) gray matter, suggesting iron deposition, is associated with physical disability, disease course, lesion load, and brain atrophy. Ambulatory dysfunction limits quality of life; however correlation with conventional MRI remains poor. METHODS: Normalized intensity on T2-weighted images was obtained in the basal ganglia, thalamus, red nucleus, and dentate nucleus in 47 MS patients and 15 healthy controls. Brain T1-hypointense and FLAIR-hyperintense lesion volume, third ventricle width, brain parenchymal fraction and timed 25 foot walk (T25FW) were measured in the MS group. RESULTS: T2 hypointensity was present throughout gray matter in MS vs. controls (all p<0.01). Dentate T2 hypointensity was the only MRI variable significantly correlated with T25FW (Pearson r=-0.355, p=0.007) and was also the best MRI correlate of physical disability (EDSS) score in regression modeling (r=-0.463, R(2)=0.223, p=0.004). CONCLUSIONS: T2 hypointensity is present in subcortical gray matter nuclei in patients with MS vs. normal controls. Dentate nucleus T2 hypointensity is independently related to ambulatory impairment and disability, accounting for more variance than conventional lesion and atrophy measures. This study adds more weight to the notion that T2 hypointensity is a clinically relevant marker of tissue damage in MS.     

视神经脊髓炎脊髓磁共振成像特征

目的 比较视神经脊髓炎(NMO)与多发性硬化(MS)的脊髓MRI特点,从MBI的角度重新认识NMO.方法 对20例MS患者和23例NMO患者的脊髓MRI进行同顾性分析.结果 NMO患者脊髓MRI多表现为线样延髓征、线样延髓脊髓征、线样脊髓征、脊髓横贯性或次横贯性损伤,且常超过3个节段(23例),而MS患者脊髓MRI病变节段短(≥3个节段者8例,χ2=19.142,P<0.01),常呈偏心性分布(17例,与NMO组比较,χ2=25.256,P<0.01).结论 NMO不同于MS,在MRI方面,病灶的分布有其自身特征,而MS的脊髓病灶与髓鞘走向一致.因此,我们从影像学角度进一步证实NMO是有异于MS的一种独立的疾病.     

The microvasculature of the spinal cord in the human adult

The microvasculature of the human spinal cord have been studied with scanning electron microscopy (SEM) on the corrosion casts of blood vessels, and light microscopy on the transparent after intra-arterial injection of Indian ink and vascular staining specimens. On the surface of the cord, the density of the pial venous plexus was higher than the pial arterial plexus. The anterior spinal artery and vein gave off central arteries and veins, which ran posteriorly within the anterior median fissure. The number of the central arteries and veins per centimeter in length is highest in the lumbosacral cord, followed by the cervical and then the thoracic cord. In this study, the central arteries and veins were classified into types; type 1 dominated the arterial system and type 2 the venous system. The central arteries and veins sent long branches both rostrally and caudally along the axis of spinal cord. The order of their length was as follows: thoracic, cervical, lumbar and sacral cord. These blood vessels overlapped each other. The peripheral arteries terminated in the periphery of the gray matter while the peripheral veins originated within the different depth of the gray matter. The posterior spinal artery supplied the posterior horn and the substantia gelatinosa. The posteromedial veins arose in the deep posterior horns and posterior funiculus, and were occasionally connected with the anterior spinal vein within the cord. Overlapped zone which was supplied by both the central and peripheral vascular system was seen within the cord, and its extent was variable at different levels. The overlapped zone of the venous supply was broader than the arterial one. The peripheral veins appeared to drain blood not only from the white matter but also from the gray matter. The distribution of the capillary networks in the gray matter was slightly denser and showed more horizontal arrangement in the lumbosacral cord, and more sparse and longitudinal in the cervicothoracic cord. The distribution of the capillary networks in the white matter was parallel to nerve fibers which run longitudinal in the whole cord. Based on the result of present study, it was considered that the circulatory disturbances are prone to occur in the thoracic cord, and the circulatory block in the arterial system of the cord tends to cause a lesion in the gray matter, whereas the circulatory disturbances in the venous system tends to cause a lesion in the white matter.     

White matter spectroscopy in neuromyelitis optica

Background   Naa/Cr ratio in normal appearing white matter (NAWM) of patients with multiple sclerosis (MS) is altered beyond plaques, suggesting early axonal loss, and correlates to clinical disability. Brain lesions not typical of MS have been described in Neuromyelitis optica (NMO), and correspond to brain aquaporin-4 channel sites, but the evaluation of Naa/Cr ratio in NAWM of patients with NMO and its association to the presence of brain lesions and clinical disability have not been described. Objectives   To evaluate the Naa/Cr of normal appearing white matter (NAWM) in 16 patients with NMO compared to healthy controls. Methods   We performed brain magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) of 16 patients with NMO and compared to age matched healthy controls. Results   NAWM Naa/Cr did not show statistical difference among patients and controls, neither between patients that had normal brain MRI and atypical brain lesions. Conclusion   NAWM was found to have a normal Naa/Cr in patients with NMO, reinforcing the concept that the white matter is not primarily affected in this disease. Drs. D. B. Bichuetti and R. L. M. Rivero contributed equally to this work.     

The regional distribution of nitric oxide synthase activity in the spinal cord of the dog

The aim of this study was to examine the distribution of calcium-dependent nitric oxide synthase activity (cNOS) in the white and gray matter in cervical, thoracic, lumbar and sacral segments of the spinal cord and cauda equina of the dog. The enzyme's activity, measured by the conversion of [3H]arginine to [3H]citrulline revealed considerable region-dependent differences along the rostrocaudal axis of the spinal cord in general and in cervical (C1, C2, C4, C6 and C8) and lumbar (L1-L3, L4-L7) segments in particular. In the non-compartmentalized spinal cord, the cNOS activity was lowest in the thoracic and highest in the sacral segments. No significant differences were noted in the gray matter regions (dorsal horn, intermediate zone and ventral horn) and the white matter columns (dorsal, lateral and ventral) in the upper cervical segments (C1-C4), except for a significant increase in the ventral horn of C4 segment. In C6 segment, the enzyme's activity displayed significant differences in the intermediate zone, ventral and lateral columns. Surprisingly, extremely high cNOS activity was noted in the dorsal horn and dorsal column of the lowest cervical segment. Comparing the enzyme's activity in upper and lower lumbar segments of the spinal cord, cNOS activity prevailed in L4-L7 segments in the dorsal horn and in all the above mentioned white matter columns.