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Introduction: Neurons are highly energy-dependent and highly specialized cells, showing great sensitivity to oxidative stress (OS). Nitric oxide (NO) and its oxidation products play a central role in neurodegeneration. This study aimed to contribute to the further elucidation of the role of OS in the pathogenesis of amyotrophic lateral sclerosis (ALS)., Methods: We assessed NO and superoxide dismutase (SOD) levels in cerebrospinal fluid (CSF) of 24 sporadic ALS (sALS) patients (13 of them presented with spinal form while 11 patients had bulbar form) and 20 controls (CG)., Results: The obtained SOD levels in sALS patients were lower than those in CG (p < 0.001), while NO showed higher levels compared to CG (p < 0.001). Observed separately, there were no significant differences in the levels of NO and SOD in CSF between patients about their clinical presentations (p > 0.05). There were significant negative correlations between SOD and NO levels in all sALS patients (r = 0.31, P = 0.025). Significant correlation between SOD and functional rating scale as well as disease progression index was recorded in patients with sALS (r = 0.618. r = 0.425, P < 0.01), while NO levels were significantly associated with disease progression only (r = 0.348, P < 0.01)., Conclusion: The data presented clearly support the role of impaired oxidant/antioxidant balance in the pathogenesis of ALS, where NO overproduction and decreased SOD defense activity seem to be particularly involved. The CSF SOD and NO level might serve as useful biomarkers for functional disorder and progression of the disease., Competing Interests: None

Background/aim: The role of nitric oxide (NO) has been established in infection over the years. NO functions by inhibiting the growth of intracellular pathogens. The present study was undertaken to ascertain the role of NO in central nervous system (CNS) infection by Mycobacterium tuberculosis., Materials and Methods: A total of 781 chronic meningitis cerebrospinal fluid (CSF) samples suspected of CNS tuberculosis (TB) were categorized based on M. tuberculosis culture positivity, anti-TB antibody response, and CSF cell count and were analyzed for NO., Results: We found that NO levels were positive in 10.88% of the CSF samples. Positivity for NO was 18%, 11.67%, 13.68%, 9.32%, and 9.66% in the cases with mycobacterial culture positivity, anti-TB antibody positivity, high cell count, low cell count, and zero cell count, respectively. Among the above cell count categories, NO levels were noticed to be elevated in high cell count samples with mononuclear cell predominance., Conclusion: This study suggests that NO might play some role in the later stages of tuberculous meningitis. This is the first study to our knowledge in which NO was evaluated in CSF in relation to immune response and the presence of a pathogen with such a large number of subjects.

Aim: To provide an up-to-date review of oxidative stress biomarkers in multiple sclerosis and thus identify candidate molecules with greatest promise as biomarkers of diagnosis, disease activity or prognosis., Method: A semi-systematic literature search using PubMed and other databases., Results: Nitric oxide metabolites, superoxide dismutase, catalase, glutathione reductase, inducible nitric oxide synthase, protein carbonyl, 3-nitrotyrosine, isoprostanes, malondialdehyde and products of DNA oxidation have been identified across multiple studies as having promise as diagnostic, therapeutic or prognostic markers in MS., Conclusion: Heterogeneity of study design, particularly patient selection, limits comparability across studies. Further cohort studies are needed, and we would recommend promising markers be incorporated into future clinical trials to prospectively validate their potential.

Nitric oxide (NO) is a soluble gas that participates in important functions of the central nervous system, such as cognitive function, maintenance of synaptic plasticity for the control of sleep, appetite, body temperature, neurosecretion, and antinociception. Furthermore, during exercise large amounts of NO are released that contribute to maintaining body homeostasis. Besides NO production, physical exercise has been shown to induce antinociception. Thus, the present study aimed to investigate the central involvement of NO in exercise-induced antinociception. In both mechanical and thermal nociceptive tests, central [intrathecal (it) and intracerebroventricular (icv)] pretreatment with inhibitors of the NO/cGMP/KATP pathway (L-NOArg, ODQ, and glybenclamide) prevented the antinociceptive effect induced by aerobic exercise (AE). Furthermore, pretreatment (it, icv) with specific NO synthase inhibitors (L-NIO, aminoguanidine, and L-NPA) also prevented this effect. Supporting the hypothesis of the central involvement of NO in exercise-induced antinociception, nitrite levels in the cerebrospinal fluid increased immediately after AE. Therefore, the present study suggests that, during exercise, the NO released centrally induced antinociception.

Interactions of adult neural stem cells (NSCs) with supportive vasculature appear critical for their maintenance and function, although the molecular details are still under investigation. Neurotrophin (NT)-3 belongs to the NT family of trophic factors, best known for their effects in promoting neuronal survival. Here we show that NT-3 produced and secreted by endothelial cells of brain and choroid plexus capillaries is required for the quiescence and long-term maintenance of NSCs in the mouse subependymal niche. Uptake of NT-3 from irrigating vasculature and cerebrospinal fluid (CSF) induces the rapid phosphorylation of endothelial nitric oxide (NO) synthase present in the NSCs, leading to the production of NO, which subsequently acts as a cytostatic factor. Our results identify a novel interaction between stem cells and vasculature/CSF compartments that is mediated by an unprecedented role of a neurotrophin and indicate that stem cells can regulate their own quiescence in response to endothelium-secreted molecules., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Decreased function of the anterior cingulate cortex (ACC) is crucially involved in the pathogenesis of depression. A key role of nitric oxide (NO) has also been proposed. We aimed to determine the NO content in the cerebrospinal fluid (CSF) and the expression of NO synthase (NOS) isoforms, that is, NOS1, NOS2, and NOS3 in the ACC in depression. In depressive patients, CSF-NOx levels (the levels of the NO metabolites nitrite and nitrate) were significantly decreased (P = 0.007), indicating a more general decrease of NO production in this disorder. This agreed with a trend toward lower NOS1-mRNA levels (P = 0.083) and a significant decrease of NOS1-immunoreactivity (ir) (P = 0.043) in ACC. In controls, there was a significant positive correlation between ACC-NOS1-ir cell densities and their CSF-NOx levels. Furthermore, both localization of NOS1 in pyramidal neurons that are known to be glutamatergic and co-localization between NOS1 and GABAergic neurons were observed in human ACC. The diminished ACC-NOS1 expression and decreased CSF-NOx levels may be involved in the alterations of ACC activity in depression, possibly by affecting glutamatergic and GABAergic neurotransmission.

Purpose: Cerebral vasospasm (CVS) is a major complication after subarachnoid hemorrhage (SAH) induced by the rupture of intracranial aneurysms. The aim of the present study was to investigate the effect and mechanism of cervical sympathetic block on cerebral vasospasm of the rabbits after SAH., Methods: After successful modeling of cervical sympathetic block, 18 healthy male white rabbits were randomly divided into three groups (n=6), ie, sham operation group (Group A), SAH group (Group B) and SAH with cervical sympathetic block group (Group C). Models of delayed CVS were established by puncturing cisterna magna twice with an injection of autologous arterial blood in Groups B and C. A sham injection of blood through cisterna magna was made in Group A. 0.5 ml saline was injected each time through a catheter for cervical sympathetic block after the first injection of blood three times a day for 3 d in Group B (bilateral alternating). 0.5 ml of 0.25% bupivacaine was injected each time through a catheter for cervical sympathetic block after the first injection of blood three times a day for 7 d in Group B. 2 ml venous blood and cerebrospinal fluid were obtained before (T1), 30 min (T2) and 7 d (T3) after the first injection of blood, respectively, and conserved in a low temperature refrigerator. Basilar artery value at T1, T2 and T3 was measured via cerebral angiography. The degree of damage to nervous system at T1 and T3 was recorded., Results: There was no significant difference in diameter of basilar artery at T1 among three groups. The diameters of basilar artery at T2 and T3 of Groups B and C were all smaller than that in Group A, which was smaller than Group C, with a significant difference. There was no significant difference in NO and NOS in plasma and cerebrospinal fluid among three groups. The NO and NOS contents at T2 and T3 of Groups B and C were all lower than Group A; Group C was higher than Group B, with a significant difference. The nerve function at T3 of Groups B and C were all lower than Group A and that of Group C higher than Group B, with a significant difference., Conclusion: Cervical sympathetic block can relieve cerebral vasospasm after subarachnoid hemorrhage and increase NO content and NOS activity in plasma and cerebrospinal fluid to promote neural functional recovery.

Objective: To determine the concentration of nitrate/nitrite in the cerebrospinal fluid and in the dorsal horn interstice of the L6-S1 spinal cord boundary in rats with or without cystitis induced by cyclophosphamide., Methods: All experiments were conducted using Wistar female rats. A microdialysis probe was implanted in the subarachnoid space or in the spinal cord tissue at the L6-S1 segments (confirmed histologically). Two days later, the microdialysis probe was perfused with artificial cerebrospinal fluid, containing or not NG-monomethyl-L-arginine. Samples were collected every 15 minutes and kept at -20ºC. Nitrite/nitrate concentrations were determined by chemiluminescence., Results: In normal animals, the mean values of nitrite/nitrate concentrations in the first microdialysate sample of the cerebrospinal fluid and of the spinal cord interstice were similar (482.5±90.2pmol/75µL, n=20, and 505.7±11.5pmol/75µL, n=6, respectively), whereas, in the samples from rats with cystitis, these values were significantly greater (955.5±66.3pmol/75µL, n=8, and 926.5±131.7pmol/75µL, n=11, respectively). In both groups, NG-monomethyl-L- arginine caused a significant reduction in the nitrite/nitrate concentration. Interestingly, the maximal reduction of nitrite/nitrate concentration caused by NG-monomethyl-L- arginine was no greater than 30% of the initial values., Conclusions: These results constitute the first demonstration that nitrite/nitrate concentrations in the cerebrospinal fluid and spinal cord interstice are elevated between 20- and 22 hours after cyclophosphamide-induced cystitis, and indicate that cystitis is associated with changes in the production of nitric oxide in the spinal cord segments, where most primary bladder afferents end.

In animal models of degenerative lumbar disease, inducible nitric oxide synthase (iNOS) is expressed in macrophages and Schwann cells following compression of the cauda equina. We previously reported that NO metabolites (nitrite plus nitrate: [NOx]) in the cerebrospinal fluid (CSF) correlate with postoperative pain relief in patients with degenerative lumbar disease and with neurologic recovery rate postoperatively or after conservative treatment in patients with spinal cord injury. The objective of the present study was to examine the relationship between [NOx] and neurologic severity, and recovery in degenerative cervical and lumbar diseases. Two hundred fifty-seven cases, including 85 patients with cervical compression myelopathy (CCM), 25 with cervical disc herniation (CDH), 70 with lumbar canal stenosis (LCS), and 77 with lumbar disc herniation (LDH), were examined. The CSF [NOx] was measured using the Griess method. Severity of neurologic impairment and clinical recovery was assessed using the Japanese Orthopedic Association score and Hirabayashi's method. [NOx] in CCM and LCS, but not CDH and LDH groups, was significantly higher than that in controls, and correlated with postoperative recovery rates, but not with preoperative neurologic severity. [NOx] significantly correlated with neurologic recovery following surgery for CCM and LCS.

Background: Bacterial meningitis is often associated with cerebral compromise which may be responsible for neurological sequelae in nearly half of the survivors. Little is known about the mechanisms of CNS involvement in bacterial meningitis. Several studies have provided substantial evidence for the key role of nitric oxide (NO) and reactive oxygen species in the complex pathophysiology of bacterial meningitis., Methods: In the present study, serum and CSF levels of NO, lipid peroxide (LPO) (mediators for oxidative stress and lipid peroxidation); total thiol, superoxide dismutase (SOD) (antioxidant mediators) and S-100B protein (mediator of astrocytes activation and injury), were investigated in children with bacterial meningitis (n = 40). Albumin ratio (CSF/serum) is a marker of blood-CSF barriers integrity, while mediator index (mediator ratio/albumin ratio) is indicative of intrathecal synthesis., Results: Compared to normal children (n = 20), patients had lower serum albumin but higher NO, LPO, total thiol, SOD and S-100B. The ratios and indices of NO and LPO indicate blood-CSF barriers dysfunction, while the ratio of S-100B indicates intrathecal synthesis. Changes were marked among patients with positive culture and those with neurological complications. Positive correlation was found between NO index with CSF WBCs (r = 0.319, p < 0.05); CSF-LPO with CSF-protein (r = 0.423, p < 0.01); total thiol with LPO indices (r = 0.725, p < 0.0001); S-100B and Pediatric Glasow Coma Scores (0.608, p < 0.0001); CSF-LPO with CSF-S-100B (r = 0.482, p < 0.002); serum-total thiol with serum S-100B (r = 0.423, p < 0.01)., Conclusion: This study suggests that loss of integrity of brain-CSF barriers, oxidative stress and S-100B may contribute to the severity and neurological complications of bacterial meningitis.

Background: The role of endothelin-1 (ET-1) and nitric oxide (NO) as two important mediators in the development of cerebral vasospasm (CVS) after subarachnoid haemorrhage (SAH) is controversial. The objective of this study was to determine whether local levels of ET-1 and NO in cerebral arterial plasma and/or in cerebrospinal fluid (CSF) are associated with the occurrence of CVS after SAH., Methods: CVS was induced using the one-haemorrhage rabbit model and confirmed by digital subtraction angiography of the rabbits' basilar artery on day 5. Prior to sacrifice, local CSF and basilar arterial plasma samples were obtained by a transclival approach to the basilar artery. Systemic arterial plasma samples were obtained. ET-1 levels were determined by immunometric technique (pg/ml +/- SEM) and total nitrate/nitrite level spectrophotometrically (micromol/l +/- SEM)., Findings: Angiographic CVS was documented after SAH induction (n = 12, P < 0.05). The ET-1 level in CSF was significantly elevated by 27.3% to 0.84 +/- 0.08 pg/ml in SAH animals (n = 7) in comparison to controls (0.66 +/- 0.04 pg/ml, n = 7, P < 0.05). There was no significant difference in ET-1 levels in systemic and basilar arterial plasma samples of SAH animals compared to controls. A significant lack of local NO metabolites was documented in basilar arterial plasma after SAH (36.8 +/- 3.1 micromol/l, n = 6) compared to controls (61.8 +/- 6.2 micromol/l, n = 6, P < 0.01)., Conclusion: This study demonstrates that an elevated ET-1 level in CSF and local lack of NO in the basilar arterial plasma samples are associated with CVS after experimental SAH.

Objective: Thoracic and thoracoabdominal aortic surgery is sometimes complicated by subacute or delayed paraplegia. Pro-inflammatory cytokine interleukin-1 (IL-1) beta has been implicated in extensive inflammation and progressive neurodegeneration after ischemia. Using a rabbit model, we investigated the neuroprotective effects of IL-1 receptor antagonist (IL-1ra) in a temporal fashion., Methods: Spinal cord ischemia was induced by aortic cross-clamping in New Zealand White rabbits. The animals were assigned to three groups. Group C (n = 20) received saline (0.2-mL) and Group I (n = 20) received IL-1ra (200-microg/0.2-mL) intrathecally just after reperfusion. Group S (n = 3) underwent sham operation without aortic occlusion. We assessed the neuroprotective effects of IL-1ra by evaluating neurological function, histopathological changes, and in-situ terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL staining). We also measured the levels of Nitric Oxide (NO) and S100beta in cerebrospinal fluid (CSF). Each evaluation was performed sequentially within 120 hours after reperfusion., Results: Group C showed progressive deterioration of motor function which became statistically significant from 48 hours after the onset of reperfusion (P < .05, P < .01, P < .001, P < .001 at 48, 72, 96, and 120 hours, respectively). Compared to Group C, a higher number of viable neurons was observed with less severe spinal cord injury in Group I (P < .01, .05 and .05 at 24, 72, and 120 hours, respectively). TUNEL-positive neurons were also significantly reduced by the administration of IL-1ra (P <.01 and .05 at 24, and 120 hours, respectively). The difference between Group C and Group I with regard to NO was significant at 72 and 120 hours (P < .05), while that in terms of S100beta was significant only at 24 hours (P < .05)., Conclusions: Administration of IL-1ra attenuates spinal cord ischemic-reperfusion injury as evidenced by reducing both neuronal necrosis and apoptosis.

Objective: Adenosine and nitric oxide (NO) are known as vasodilatators. We investigated adenosine deaminase (ADA) activity and NO concentration in the cerebrospinal fluid (CSF) of patients with subarachnoid hemorrhage (SAH)., Methods: Forty patients with SAH and 10 controls were included in the study. Nitrate level and ADA activity were measured in CSF. SAH patients were grouped according to the presence of angiographic vasospasm, Hunt and Hess grading, Glasgow Coma Scale (GCS) and Fisher Grade (FG)., Results: The level of NO markers in SAH patients decreased when compared to that in the control group (p < 0.05). However, NO markers in patients with vasospasm was higher than in that of patients without vasospasm (p < 0.05). ADA activity increased in patients with SAH (p < 0.01) and also patients with angiographic vasospasm (p < 0.05). ADA activity in the poor-grade SAH group was higher than that in the good-grade SAH group. The group with the lower GCS showed increased ADA activity compared to those with a higher GCS score (p < 0.01). Furthermore, patients with FG 4 had a higher level of ADA activity compared to FG 1 and 2 and FG 3 (p < 0.001 and p < 0.01, respectively)., Conclusion: Decreased NO level may participate in the early development of vasospasm. However, the increased level of ADA activity in the SAH patients with the poor clinical and consciousness level may have resulted from the ischemic cerebral insult.

In animal models of spinal cord injury (SCI), inducible NO (nitric oxide) synthase is expressed in the spinal cord immediately after sustaining SCI. Excessive NO production has cytotoxic effects and induces neuronal apoptosis, causing neural degeneration and neurodysfunction in the spinal cord. Little is known, however, about the relationship between NO(x) (NO metabolites: nitrite and nitrate) levels in the cerebrospinal fluid (CSF) and neurologic severity or recovery in clinical cases. The objective of the present study was to examine the correlation between CSF NO(x) levels and neurologic severity or recovery in SCI. Twenty-five patients with incomplete cervical cord injury (CCI) were examined. Eight cases were treated conservatively (non-operated group). Seventeen cases underwent surgical intervention (operated group). NO(x) levels in the CSF were measured using the Griess method. The severity of the neurologic impairment was assessed using Frankel's classification and the American Spinal Injury Association motor score (ASIA MS). The degree of neurologic recovery was assessed using Frankel's classification and the ASIA motor recovery percentage (MRP). There was no significant difference in the NO(x) levels between the CCI group (NO(x) levels: 5.9 +/- 0.7 microM) and the 36 control subjects (1 volunteer and 35 patients without neurologic disorders, NO(x) levels: 4.9 +/- 0.3 microM). There was no significant difference in NO(x) levels and MRP between the non-operated group and the operated group. The NO(x) levels in total SCI group were significantly correlated with the ASIA MS and MRP. There was a significant correlation between CSF NO(x) levels and neurologic severity or recovery in incomplete CCI.

Neuroinflammatory (demyelinating) disease is a rare but feared complication of treatment with anti-tumour necrosis factor (TNF)alpha in patients with polyarthritis. In this study, blood and cerebrospinal fluid markers of inflammation were analysed in 10 people with polyarthritis before and during treatment with infliximab. An increased systemic expression of interferon (IFN)gamma was detected. Systemic administration of IFNgamma is known to exacerbate multiple sclerosis. However, the present study failed to detect signs of inflammation in the cerebrospinal fluid samples-that is, pleocytosis, oligoclonal immunoglobulin G bands, increased expression of IFNgamma, TNFalpha or interleukin 10, or increased levels of nitric oxide oxidation products. Our initial hypothesis, that the few cases of clinical neuroinflammatory disorders observed during treatment of polyarthritis with anti-TNFalpha represent the extreme end of a commonly occurring minor intrathecal immune activation, which in most cases does not give any overt neurological dysfunction, was not supported. Induction of systemic IFNgamma production may still be relevant in neuroinflammation associated with treatment with anti-TNFalpha.

Background: There is no information regarding the possible role of cerebral substrates in the pathogenesis of neuronal injury in intracerebral haemorrhages (ICHs). Purposes of this prospective study were to clarify whether changes in substrates are the consequence of the initial brain damage in ICH and to elucidate the relationship among the biochemical mechanisms and clinical course of patients with ICH., Method: During a period of two years, patients (GCS < or =8) who had ICH secondary to an aneurysm (SAH), stroke (sICH), or trauma (tICH) and underwent ventriculostomy with ICP monitoring and/or underwent cranial surgery were randomly enrolled in this study. Extracellular concentrations of glutamate, aspartate, glycine, GABA, lactate, lactate/pyruvate ratio, and glucose in the CSF were measured by use of high-performance liquid chromatography (HPLC). The nitric oxide (NO) concentration in the CSF was analyzed by chemiluminescence., Findings: There were 75 patients (38 women and 37 men) with ICH included in this study. Twenty-one patients had SAH, 28 sICH, and 26 tICH. In tICH patients, there was a 30-fold increase in glutamate and a 10-fold in aspartate over reference values. The levels of glutamate, aspirate, GABA, lactate, glucose, and NO differed significantly among the three groups (p<0.001). There were no significant differences in glycine and L/P ratio among the groups. The initial GCS, the mean CPP and outcome six months after the insult were all significantly correlated with the concentration of substrates (p<0.01), both within groups and among the total sample. The CSF levels of glutamate lactate, NO and glucose correlated significantly with outcome (p<0.005)., Conclusions: This study confirms the correlation between the level of EAAs and the outcome of ICHs, suggesting that neurochemical monitoring of these substances may have a role in caring for patients.

Hypotension reduces cerebral O(2) supply, which may result in brain cell damage and loss of brain cell function in the near-term neonate. The aim is to elucidate 1) to what extent the functional disturbance of the cerebral cortex, as measured with electrocortical brain activity (ECBA), is related to cerebral cortical tissue damage, as estimated by MAP2; and 2) whether there is a relationship between the glutamate, nitric oxide (NO), cGMP pathway and the development of cerebral cortical tissue damage after hemorrhagic hypotension. Seven lambs were delivered at 131 d of gestation. Hypotension was induced by withdrawal of blood until mean arterial blood pressure was reduced to 30% of normotension. Cerebral O(2) supply, consumption, and ECBA were calculated in normotensive conditions and after 2.5 h of hypotension. Concentrations of glutamate and aspartate in cerebrospinal fluid (CSF), NO(2) and NO(3) (NOx) in plasma, and cGMP in cortical brain tissue were determined in both conditions. CSF and brain tissue from siblings were used to determine normotensive values. Cortical neuronal damage was detected after 2.5 h of hypotension. ECBA was negatively related to the severity of the cortical damage. ECBA was related to respectively glutamate, NOx, and cGMP concentrations. In conclusion, cortical neuronal damage is detected after 2.5 h of hemorrhagic hypotension in the near-term born lamb. The damage is reflected by a reduction of ECBA. The glutamate, NOx, cGMP pathway is likely to be involved in the pathogenesis of cerebral cortical damage.

Unlabelled: In this study, we investigated the effects of 1.0 and 2.0 minimum alveolar anesthetic concentration (MAC) sevoflurane on cerebral blood flow (CBF) autoregulation before and after nonselective inhibition of nitric oxide (NO) synthase in rats. Rats were randomly assigned as follows: Group 1 (n = 8): 1.0 MAC sevoflurane; Groups 2 and 3 (n = 8 per group): 2.0 MAC sevoflurane. Assessment of autoregulation within a mean arterial blood pressure range of 140-60 mm Hg was performed by graded hemorrhage before and after administration of l-arginine methyl ester (l-NAME, 30 mg/kg IV, Groups 1 and 2) or during hypocapnia (Group 3). In 10 additional animals, brain tissue NO(2)(-) concentrations were measured at 1.0 and 2.0 MAC sevoflurane. CBF autoregulation was maintained with 1.0 MAC sevoflurane (Group 1) regardless of NO synthase status indicating that CBF autoregulation might not be related to NO availability. Sevoflurane dose-dependently increased brain tissue NO(2)(-) and impaired CBF autoregulation. Administration of l-NAME (Group 2) but not hypocapnia (Group 3) restored CBF autoregulation. This suggests that sevoflurane impairs the autoregulatory capacity secondary to an increase of the perivascular NO availability and questions the importance of basal cerebrovascular tone in terms of vasodilatory capacity during hypotensive challenges., Implications: The present study suggests that the volatile anesthetic sevoflurane dose-dependently impairs cerebrovascular autoregulation by mechanisms secondary to increase of perivascular nitric oxide availability.

Electrically active axons degenerate in the presence of nitric oxide (NO) in vitro. High CSF NO concentrations have been observed in patients with hemorrhagic brain injury such as subarachnoid hemorrhage (SAH) and intracerebral hemorrhage (ICH). This study investigated the evidence for axonal injury in SAH and ICH and related this to CSF NO levels. In this study, neurofilament phosphoforms (NfH(SMI34), NfH(SMI35), NfH(SMI38), NfH(SMI310)), surrogate markers for axonal injury, and NO metabolites (nitrate, nitrite = NOx) were measured by ELISA in cerebrospinal fluid (CSF) from patients with SAH and ICH and from a group of controls. Injury severity was classified using the Glasgow Coma Scale, and survival was used as the outcome measure. Compared to the control group, a higher proportion of patients with SAH and ICH had elevated NfH(SMI34) levels from day 0 to day 6 (p < 0.001), elevated NfH(SMI35) levels from day 1 to 6 (p < 0.001), and elevated NfH(SMI310) levels at day 0, 1, 4, and 6 (p < 0.001). The NOx levels were higher in the SAH and ICH patients than in the controls (p < 0.05) and distinguished the non-survivors from the survivors (p < 0.05). No direct correlation was found for NOx with any of the NfH phosphoforms. This study provides evidence for primary and secondary axonal injury in patients with SAH and ICH, with non-survivors also having higher NOx levels. CSF NfH phosphoforms might emerge as a putative surrogate marker for monitoring the development for secondary axonal degeneration in neurocritical care and guiding targeted neuroprotective strategies.

Background: Japanese encephalitis virus (JEV), the mosquito-borne flavivirus, annually causes an estimated 35,000-50,000 encephalitis cases and 10,000-15,000 deaths in Asia, and there is no antiviral treatment. The role played by the immune response in determining the outcome of human infection with JEV is poorly understood, although, in animal models of flavivirus encephalitis, unregulated proinflammatory cytokine responses can be detrimental., Methods: We studied the innate, cellular, and humoral immune responses in 118 patients infected with JEV, of whom 13 (11%) died., Results: Levels of interferon (IFN)- alpha , the proinflammatory cytokine interleukin (IL)-6, and the chemokine IL-8 were all higher in the cerebrospinal fluid (CSF) of the nonsurvivors than of the survivors (P=.04, P=.006, and P=.04, respectively), as were both the IL-6 : IL-4 ratio in CSF (a marker of the balance of pro- and anti-inflammatory cytokines) and the level of the chemokine RANTES (regulated on activation, normally T cell expressed and secreted) in plasma (P=.03). In contrast, levels of immunoglobulin (Ig) M and IgG in CSF and of IgM in plasma were higher in the survivors (P=.035, P=.003, and P=.009, respectively). Levels of IFN- gamma and nitric oxide did not vary with outcome., Conclusions: During JEV infection, elevated levels of proinflammatory cytokines and chemokines are associated with a poor outcome, but whether they are simply a correlate of severe disease or contribute to pathogenesis remains to be determined.

Equine protozoal myeloencephalitis (EPM) is a disease of horses that is primarily associated with infection with the apicomplexan Sarcocystis neurona. Infection with this parasite alone is not sufficient to induce the disease, and the mechanism of neuropathogenesis associated with EPM has not been reported. Nitric oxide (NO) functions as a neurotransmitter, a vasodilator, and an immune effector and is produced in response to several parasitic protozoa. The purpose of this work was to determine if the concentration of NO metabolites (NO(x)(-)) in the cerebrospinal fluid (CSF) is correlated with the development of EPM. CSF NO(x)(-) levels were measured before and after transport-stressed, acclimated, or dexamethasone-treated horses (n = 3 per group) were experimentally infected with S. neurona sporocysts. CSF NO(x)(-) levels were also compared between horses that were diagnosed with EPM after natural infection with S. neurona and horses that did not have clinical signs of disease or that showed no evidence of infection with the parasite (n = 105). Among the experimentally infected animals, the mean CSF NO(x)(-) levels of the transport-stressed group, which had the most severe clinical signs, was reduced after infection, while these values were found to increase after infection in the remaining groups that had less severe signs of EPM. Under natural conditions, horses with EPM (n = 65) had a lower mean CSF NO(x)(-) concentration than clinically normal horses with antibodies (Abs) against S. neurona (n = 15) in CSF, and horses that developed ataxia (n = 81) had a significantly lower mean CSF NO(x)(-) concentration than horses that did not have neurologic signs (n = 24). In conclusion, lower CSF NO(x)(-) levels were associated with clinical EPM, suggesting that measurement of CSF NO(x)(-) levels could improve the accuracy of diagnostic tests that are based upon detection of S. neurona-specific Abs in CSF alone and that reduced NO levels could be causally related to the development of EPM.

Unlabelled: It is still unclear which neurotransmitters are involved in labor pain. We measured the concentrations of excitatory amino acids, nitric oxide, and prostaglandin E2 in the cerebrospinal fluid (CSF) of pregnant women, particularly in those with labor pain. The patients included in the study consisted of women who underwent cesarean delivery either with labor pain (Labor Pain group, n = 40) or without labor pain (Nonlabor Pain group, n = 58). All patients received spinal anesthesia (intrathecal injection of 10-12 mg of bupivacaine) for the operation, and 2 mL of CSF was collected before bupivacaine injection. Concentrations of aspartate and glutamate (0.50 +/- 0.06 microM and 0.79 +/- 0.10 microM, respectively) were significantly larger in the Labor Pain group than in the Nonlabor Pain group (0.35 +/- 0.03 microM and 0.54 +/- 0.04 microM, P < 0.05). There were no significant differences in the concentrations of nitric oxide and prostaglandin E2 between the groups. A positive correlation was found between CSF concentrations of excitatory amino acids and labor pain., Implications: The excitatory amino acids, aspartate and glutamate, play a role in labor pain. N-methyl-D-aspartate receptor antagonists may be useful for labor pain and postlabor uterine contraction pain relief.

We studied total nitric oxide (nitrite + nitrate) (NO) levels in cerebrospinal fluid (CSF) of chronic spinal diseases in nonsmokers (133 patients: 76 men and 57 women; mean age, 63 years; range, 15-92 years) by the Griess method to clarify the role of NO in different spinal diseases. The extent of compression in terms of numbers of disc level at the compressed spinal nerve and neurological evaluation were also assessed according to the Japanese Orthopaedic Association scores. The spinal diseases included cervical myelopathy and radiculopathy (cervical disease group), ossification of yellow ligament (thoracic disease group), and lumbar disc herniation, lumbar canal stenosis and lumbar spondylolisthesis (lumbar disease group). NO levels in the spinal disease groups (4.98+/-2.28 micromol/l: mean +/- SD) were significantly higher than that in the control group (2.53+/-0.94 micromol/l). An inverse correlation was detected between the elevated levels of NO and the grade of clinical symptoms in the cervical disorders. The number of disc level at the compressed spinal nerve was positively correlated with elevated NO levels in CSF in the cervical and lumbar disorder groups. These results indicate that nerve compression may elevate NO levels in CSF, and that NO concentration in the CSF might be a useful marker of damage to nervous system in spinal disorders.

Objective: To investigate systemic and intrathecal production of proinflammatory cytokines in relation to cerebrospinal fluid (CSF) nitric oxide (NO) release in patients with neuropsychiatric lupus erythematosus (NPLE)., Methods: Thirty patients with NPLE rated as mild, moderate, or severe were studied and CSF was obtained from 21 of these. Cytokine mRNA expressing cells were detected by in situ hybridisation. Soluble cytokines were assessed by enzyme linked immunosorbent assay (ELISA). Nitrite and nitrate were determined by capillary electrophoresis., Results: Patients with NPLE had high numbers of lymphocytes expressing mRNA for tumour necrosis factor alpha (TNFalpha), interferon gamma, and interleukin 10 in blood. The number of peripheral blood TNFalpha mRNA positive cells correlated strongly with the level of NO metabolites in the CSF (r(2)=0.69). Both the number of peripheral blood mononuclear cells expressing mRNA for TNFalpha as well as the CSF level of NO metabolites correlated with NPLE disease severity., Conclusion: These data suggest that increased peripheral production of proinflammatory cytokines such as TNFalpha may contribute both to an increased production of NO in the central nervous system and to generation of clinical NPLE. The data also support the possibility that measurements of NO metabolites in CSF may be of value in the diagnosis of neurological symptoms related to SLE.

Background: To investigate whether nitric oxide (NO) contributes to formation of abnormal collateral circulation in patients with moyamoya disease., Methods: Cerebrospinal fluid (CSF) samples were obtained from the subarachnoid space of the Sylvian fissure during combined bypass surgery for moyamoya disease and kept frozen until NO metabolites, nitrate and nitrite, were measured using a Griess method., Results: Compared with control CSF obtained from 18 patients with hemifacial spasm, unruptured aneurysm, etc., concentrations of NO metabolites in 26 CSF samples of 18 patients with moyamoya disease were significantly higher (mean +/- SE; 17.6 +/- 1.2 vs. 10.5 +/- 1.0 microM, p < 0.01). In eight patients, the CSF samples from both the first and second operation could be obtained. NO metabolite concentrations (20.5 +/- 2.3 microM) in CSF obtained from the first surgery decreased to 15.7 +/- 1.8 microM (p < 0.01) in CSF obtained from the second, contralateral procedure. The cases of moyamoya disease with greater development of moyamoya vessels at angiographic stage 3 and 4 tended to show higher concentrations of NO metabolites than cases at earlier or later stages with a few moyamoya vessels., Interpretation: Nitric oxide concentrations in CSF are chronically elevated in moyamoya disease, probably reflecting development of abnormal collateral circulation. i.e. moyamoya vessels. Vascular bypass surgery can reduce abnormal collateral circulation with reduced production of nitric oxide.

Background: Increasing evidence has suggested the possibility that the activation of N-methyl-D-aspartate (NMDA) receptors modulates spinal nociceptive transmission via a nitric oxide (NO)/cyclic guanosine 3',5'-monophosphate (cGMP) pathway. However, the existence and the role of an NO/cGMP pathway in the modulation of spinal nociceptive transmission has been unclear. The authors hypothesized that the activation of NMDA receptors stimulates an NO/cGMP pathway, and this pathway evokes glutamate release within the spinal cord, modulating spinal nociceptive transmission., Methods: The authors have examined the effects of an NO synthase inhibitor and a soluble guanylate cyclase inhibitor on the concentrations of NO metabolites (NO2-/NO3-) and glutamate in the cerebrospinal fluid after intrathecal perfusion of NMDA, concomitantly observing pain-related behavior (scratching, biting, and vocalization) in unanesthetized, free-moving rats using an intrathecal microdialysis method. The contents of cGMP in the dorsal horn were also measured using enzyme immunoassay method., Results: Intrathecal perfusion of NMDA produced pain-related behavior and increased glutamate and NO2-/NO3-concentrations in a dose-dependent manner. A competitive NMDA receptor antagonist, D,L-2-amino-5-phosphonovaleric acid, completely blocked the NMDA-induced responses. An NO synthase inhibitor, N(G)-monomethyl-L-arginine acetate, at a dose that completely blocked the increase in NO2-/NO3-, inhibited both the NMDA-induced pain-related behavior and the increase in glutamate concentration. In addition, a soluble guanylate cyclase inhibitor, 1H-[1,2,4]oxadiazole[4,3-a]quinoxaline-1-one, also inhibited significantly NMDA-induced pain-related behavior and the increase in glutamate concentration. NMDA induced an increase in cGMP in the dorsal half of the spinal cord, which was blocked by N(G)-monomethyl-L-arginine acetate., Conclusions: The results of this study support the hypothesis that the activation of NMDA receptors modulated pain-related behavior via an NO/cGMP/glutamate release cascade within the spinal cord.

A human immunodeficiency virus type 1 (HIV)-seropositive, antiretroviral-naive patient presented with significant cognitive dysfunction. Neuropsychologic, neuroradiologic, immunologic, and virologic studies confirmed HIV-associated dementia (HAD). After 12 weeks of highly active antiretroviral therapy (HAART) with ibuprofen, dramatic improvements were demonstrated in neurologic function and were sustained for > 1 year. HIV-1 RNA in cerebrospinal fluid (CSF) decreased from 10(5) to 10(4) copies/mL after 4 weeks. After 20 weeks of therapy, plasma viremia decreased from 10(6) copies/mL to undetectable (< 96 copies/mL). Assays of neurotoxins (tumor necrosis factor-alpha, quinolinic acid, and nitric oxide) in plasma and CSF were considerably elevated at presentation and significantly decreased after therapy. Baseline plasma and CSF demonstrated neurotoxic activities in vitro, which also reduced markedly. These data, taken together, support the notion that HAD is a reversible metabolic encephalopathy fueled by viral replication. HAART used with nonsteroidal antiinflammatory agents leads to the suppression of inflammatory neurotoxins and can markedly improve neurologic function in HAD.

It has been suggested that nitric oxide (NO) plays an important role in the pathogenesis of severe falciparum malaria. Since NO has a very short half-life, nitrate and nitrite (NOx) levels, stable metabolites of NO, are used as measures of NO production. We measured plasma NOx levels in 24 adults with severe falciparum malaria on the Thai-Burmese border. After correction for renal function, there was no correlation between plasma NOx levels, or the total amount of NOx excreted in the urine, and disease severity. Plasma NOx levels decreased after the first 48 hr in all patients (P = 0.007), suggesting decreased NO production. The NOx levels in cerebrospinal fluid (CSF) correlated well with plasma NOx levels, but these did not show a correlation with coma depth, and were not significantly different from those in a healthy control group. These findings do not support the hypothesis that excessive NO production contributes to the pathogenesis of severe falciparum malaria. However, local changes in NO production, e.g., in the central nervous system, might not be reflected in the total NOx production or NOx levels in the CSF.

Cerebrospinal fluid samples from 130 children who presented with cerebral malaria were investigated to elucidate the impact of biopterin production, NO formation, and local immune activation on the clinical course of this disease. Biopterin levels were significantly lower in patients who were in a deeper coma (P = .02). Cerebrospinal fluid concentrations of NO were significantly higher in children who died than in survivors (P = .037); however, this was not the case for macrophage activation markers, neopterin, and soluble tumor necrosis factor receptor p75 (sTNFR-75). Biopterin, neopterin, and sTNFR-75 but not NO concentrations were significantly related to each other. Low biopterin levels in deep coma are compatible with an impaired local Th1 response, but the low levels could also be due to the scavenging of radicals or to decreased neurotransmitter synthesis. Local production of NO, most likely by nonimmune mechanisms, may be detrimental in cerebral malaria; however, this appears not to be the case for local Th1-mediated immune pathways.

To investigate the role of nitric oxide (NO) in bacterial meningitis, concentrations in serum, cerebrospinal fluid (CSF), or both of the precursor (L-arginine) and degradation products of NO (nitrate, nitrite) and tumor necrosis factor (TNF)-alpha were measured in 35 patients and 30 controls. CSF nitrate levels were significantly elevated, mainly due to increased blood-brain barrier permeability, and are therefore not a good parameter for gauging endogenous NO production in the CSF compartment. CSF NO/nitrite levels were significantly elevated in patients. NO/nitrite levels decreased over time (26%/6 h; P < .001). CSF levels of NO/nitrite correlated with those of TNF-alpha (r = .55; P = .001) and glucose (r = -.43; P = .02). CSF levels of L-arginine were lower in patients than in controls (P < .001). Dexamethasone did not exert a significant effect on NO metabolism. In conclusion, enhanced NO production may contribute to anaerobic glycolysis and neurologic damage in bacterial meningitis.