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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 and Objective  Cerebral vasospasm (CV) is a serious complication of subarachnoid hemorrhage (SAH) with high morbidity and mortality rates. The mechanism of CV has not been determined. There are many theories related to this unsolved issue, one of which supports CV as a two-stage phenomenon from a pathophysiologic perspective. The first stage consists of inhibition of neuronal nitric oxide synthase by oxyhemoglobin, which results in a decrease of nitric oxide (NO) production. The second stage consists of an increase in the levels of asymmetric dimethylarginine through bilirubin oxidation products (BOXes), which are oxidized by-products of hemoglobin metabolism. These in turn inhibit endothelial nitric oxide synthase (eNOS), which results in the blockage of the second NO production mechanism. BOXes are sensitive to visible light, as is their precursor bilirubin. The hypothesis of CV prevention using the photosensitivity of BOXes was tested in this study. Material and Methods  Cerebrospinal fluid (CSF) obtained from two patients with SAH was divided in half and either exposed to a standard dose of visible light or not exposed to any light. The CSF was spectrophotometrically investigated and the concentration of BOXes was measured. A comparison between CSF samples exposed to light and not exposed to light was made. Using two groups of 16 rats each, the vasospastic effect of the CSF exposed and not exposed to light on arteries of the cortical surface was measured. The cortex was exposed using the cranial window. Results  Spectrophotometric analysis revealed that the concentration of BOXes in the CSF decreased significantly after being exposed to visible light ( p  < 0.001). There was a significant difference of the vasospastic effect of CSF on exposed cortical arteries ( p  < 0.001). Conclusion  The concentration of BOXes and the vasospastic effect of CSF taken from patients with SAH were significantly reduced after being exposed to visible light if compared with CSF not exposed to light., Competing Interests: Disclosure The authors report no conflicts of interest in this work., (Georg Thieme Verlag KG Stuttgart · New York.)

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.

The aim of this study was to analyze the effect of IL-1ra (an Interleukin-1 receptor antagonist) on sepsis-induced alterations in vasopressin (AVP) and nitric oxide (NO) levels. In addition, IL-1ra effect on the hypothalamic nitric oxide synthase (NOS) activities and survival rate was also analyzed. After Wistar rats were intracerebroventricular injected with IL-1ra (9 pmol) or vehicle (PBS 0.01 M), sepsis was induced by cecal-ligation and puncture (CLP). Blood, CSF, and hypothalamic samples were collected from different groups of rats (n = 8/group) after 4, 6, and 24 h. AVP and NO levels were greatly increased in CLP. Both total NOS and inducible NOS (iNOS) activities were also greatly increased in CLP rats. These changes in AVP, NO, and NOS were not observed in sham-operated control rats. IL-1ra administration did not alter plasma AVP levels after 4 and 6 h as compared to vehicle in CLP animals but after 24 h were significantly (P < 0.01) higher in IL-1ra-treated animals. IL-1ra administration significantly (P < 0.01) decreased NO concentration in CSF but not in plasma. Both total NOS and iNOS activities were also significantly decreased by IL-1ra at 24 h in CLP animals. Moreover, the 24 h survival rate of IL-1ra-treated rats increased by 38 % in comparison to vehicle administered animals. The central administration of IL-1ra increased AVP secretion in the late phase of sepsis which was beneficial for survival. We believe that one of the mechanisms for this effect of IL-1ra is through reduction of NO concentration in CSF and hence lower hypothalamic iNOS activities in the septic rats.

Objectives: Cerebral vasospasm (CVS) and early brain injury are major causes of morbidity and mortality following subarachnoid hemorrhage (SAH). We investigated the efficiency of human tissue kallikrein (HTK) to prevent CVS in a rabbit model of SAH., Methods: Forty-eight Japanese white rabbits were randomly divided into four groups (n = 12 each): control (sham-operated), SAH, SAH + phosphate-buffered saline (PBS, vehicle), and SAH + HTK. Basilar artery (BA) diameters were measured by three-dimensional computed tomography angiography at three time points. Endothelin-1 (ET-1) and nitric oxide (NO) levels in the cerebrospinal fluid (CSF) were assayed 24 h before and 5 and 7 days after SAH. After the last measurement, the animals were killed, and endothelial cell apoptosis was assessed. Bax and Bcl-2 levels in the BA were measured by western blotting., Results: HTK was found to significantly reduce CVS following SAH in rabbits. Inverse changes were observed in ET-1 and NO levels in the CSF collected from the SAH group. HTK increased levels of NO, which has a vasodilatory effect, but did not affect levels of ET-1, which has a vasoconstrictive effect. CTA revealed that HTK treatment significantly increased BA diameter. Moreover, HTK treatment reduced the number of apoptotic cells following SAH, presumably by increasing and decreasing Bcl-2 and Bax expression, respectively., Conclusion: HTK ameliorated CVS and inhibited apoptosis in the BA in a rabbit model of SAH.

Background: Early brain injury (EBI) has recently been identified as the main factor of poor prognosis for subarachnoid hemorrhage (SAH), and apoptosis has an important function in EBI. Although nitric oxide (NO) and caspase-12, a specific molecule related to endoplasmic reticulum (ER) stress-induced apoptosis signaling pathways, are involved in brain injury after SAH, the relationship between NO and ER stress has not been reported yet. We examined the NO and caspase-12 contents and investigated the relationship between NO and ER stress-induced apoptosis., Methods: Sprague-Dawley rats (n = 90), weighing 300 g to 350 g, were used for the SAH model. SAH was induced in rats by blood injection into the prechiasmatic cistern. NO, caspase-12, and apoptosis were measured by nitrate reductase method, real-time polymerase chain reaction, and terminal deoxynucleotidy1 transferase-mediated dUTP nick-end labeling staining, respectively, at different time points after SAH. Pearson correlation coefficients were used to examine correlation., Results: NO level of cerebrospinal fluid significantly increased in the SAH group at 3, 24, 48, and 72 h compared with other groups. Caspase-12 also significantly increased at 1, 3, 6, 24, 48, and 72 h. Cell apoptosis significantly increased at 24, 48, and 72 h. A significant correlation between the number of apoptotic neurons and caspase-12 was found. NO was also correlated with caspase-12., Conclusions: Our results suggest that NO is involved in the pathophysiological events of EBI after SAH by increasing caspase-12, which results in neuronal apoptosis.

Purpose: The methylenetetrahydrofolate reductase (MTHFR) 677C>T and 1298A>C polymorphisms, which are associated with hyperhomocysteinemia and nitric oxide (NO) deficiency (which is related to atherothrombosis and cerebral ischemia), have not been studied in moyamoya disease. A case-control study was performed to investigate whether the MTHFR 677C>T and 1298A>C polymorphisms contribute to moyamoya disease (MMD)., Methods: One hundred and seven Korean patients with MMD (mean age, 20.85 ± 15.89 years; 66.4 % female) and 232 healthy control subjects (mean age, 23.99 ± 16.16 years; 56.8 % female) were included. Genotyping for the MTHFR 677C>T and 1298A>C polymorphisms and measurements of homocysteine, folate, vitamin B12, and NO in the cerebrospinal fluid (CSF) were performed. The statistical analysis was performed by multivariate linear regression and logistic regression., Result: The MTHFR 677CT+TT genotype frequency was significantly increased with early-onset MMD (<10 years) compared with late-onset MMD (≥10 years) (adjusted odds ratio, 3.392; 95 % confidence interval, 1.294-8.893, P = 0.013). The MTHFR 677C-1298C/677T-1298A diplotype (1.71 ± 1.23 arbitrary units) presented significantly lower NO levels in the CSF compared with the 677C-1298A/677C-1298A diplotype (11.40 ± 12.24 arbitrary units)., Conclusion: The MTHFR 677C>T and 1298A>C polymorphisms have restricted roles in the Korean MMD population. Therefore, further studies involving larger and more heterogeneous cohorts are needed to extend our understanding of the influence of polymorphisms in MTHFR and other thrombophilic genes on MMD.

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.

Nitric oxide has a definitive role in the complex pathophysiology of traumatc brain injury (TBI). This prospective cohort study investigated the changes in nitric oxide metabolite (NOx) levels in cerebrospinal fluid (CSF) and their correlation with factors associated with severity and prognosis after severe TBI. NOx levels were measured in CSF obtained via ventriculostomy in 44 adult patients admitted after severe TBI (Glasgow Coma Scale ≤ 8/15). The overall mean level of CSF NOx in the study population was 7.40 ± 1.59 μmol/L. Levels of CSF NOx were found to be significantly higher in subgroups of patients with poorer outcome measured by Glasgow Outcome Scale score (p < 0.042), in patients with high intracranial pressure (ICP) readings (p < 0.027) and in those with higher Marshall computed tomography (CT) grading scores (p < 0.026). Simple logistic regression demonstrated that CSF NOx levels were a significant predictor of ICP (b = 0.493, 95%CI: 1.03, 2.58, p = 0.033). A patient with 1 μmol/L increase in NOx level had 1.6 times the odds to have an ICP ≥ 20 mmHg when other confounders were not adjusted. NOx level is also a significant predictor of Marshall CT grading (b = 0.473, 95%CI: 1.02, 2.50, p = 0.037). A patient with 1 μmol/L increase in NOx level had 1.6 times the odds to have a high Marshall grade when other confounders were not adjusted. It can be concluded that CSF NOx levels may serve as a potentially useful biomarker in severe TBI given its significant association with ICP readings as well as Marshall CT grading.

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.

Despite intensive research efforts, by our own team and many others, the molecules responsible for acute neurological damage following subarachnoid hemorrhage (SAH) and contributing to delayed ischemic neurological deficit (DIND) have not yet been elucidated. While there are a number of candidate mechanisms, including nitric oxide (NO) scavenging, endothelin-1, protein kinase C (PKC) activation, and rho kinase activation, to name but a few, that have been investigated using animal models and human trials, we are, it seems, no closer to discovering the true nature of this complex and enigmatic pathology. Efforts in our laboratory have focused on the chemical milieu present in hemorrhagic cerebrospinal fluid (CSF) following SAH and the interaction of the environment with the molecules generated by SAH and subsequent events, including NO scavenging, immune response, and clot breakdown. We have identified and characterized a group of molecules formed by the oxidative degradation of bilirubin (a clot breakdown product) and known as BOXes (bilirubin oxidation products). We present a synopsis of the characterization of BOXes as found in human SAH patients' CSF and the multiple signaling pathways by which BOXes act. In summary, BOXes are likely to play an essential role in the etiology of acute brain injury following SAH, as well as DIND.

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.

One of the main functions of L-arginine (ARG) is the synthesis of nitric oxide (NO). NO is an important regulator of physiological processes in the central nervous system (CNS). NO promotes optimal cerebral blood flow, consolidates memory processes, facilitates long-term potentiation, maintains sleep-wake cycles, and assists in normal olfaction. However, at pathological levels, NO adversely affects brain function producing nitroxidative stress and promoting development of neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease and other disorders of the CNS. This review summarizes current knowledge of the role of NO in the CNS and the role of diet in regulating the levels of NO.

Aim: Cerebral vasospasm is a leading cause of death and disability following aneurysmal subarachnoid hemorrhage (SAH). Nitric oxide (NO) is a potent mediator of vasodilation, and citrulline is a known contributor to NO production. The leukocytosis inflammatory response can increase vasoconstrictive compounds that may also contribute to vasospasm. Dexamethasone is a glucocorticosteroid commonly administered after SAH, which may alter the production of leukocytes and citrulline. The goal of this project was to study the effects of dexamethasone on leukocytosis, citrulline, and angiographic vasospasm., Methods: Experimental SAH was induced in 18 New Zealand white rabbits. Intravenous dexamethasone was administered to one group (N.=9) at 2 mg/kg/day. A placebo group (N.=9) was given a saline infusion with otherwise identical procedures. CSF citrulline, leukocytes, protein, and glucose, as well as plasma citrulline were measured at baseline and 3 days post-SAH in a blinded fashion. Basilar artery angiography was performed at baseline and repeated 3 days post-SAH., Results: The change in CSF citrulline from day 0 to day 3 was significantly lower in the dexamethasone group compared to controls (P=0.002). The change in CSF white blood cells was also significantly lower (P=0.005). There was no significant change in plasma citrulline levels or angiographic vasospasm., Conclusion: Dexamethasone significantly decreases CSF citrulline and CSF leukocytosis after experimental SAH. It is possible this could lead to a relative vasoconstriction and vasodilation, respectively. These processes could cancel-out opposing effects of dexamethasone on cerebral vasospasm, partially contributing to the recognized, multifactorial, inconsistent effects of glucocorticoids on vasospasm.

Object: Subarachnoid hemorrhage (SAH)-induced vasospasm is a significant underlying cause of aneurysm rupture-related morbidity and death. While long-term intravenous infusion of sodium nitrite (NaNO(2)) can prevent cerebral vasospasm after SAH, it is not known if the intravenous administration of this compound can reverse established SAH-induced vasospasm. To determine if the intravenous infusion of NaNO(2) can reverse established vasospasm, the authors infused primates with the compound after SAH-induced vasospasm was established., Methods: Subarachnoid hemorrhage-induced vasospasm was created in 14 cynomolgus macaques via subarachnoid implantation of a 5-ml blood clot. On Day 7 after clot implantation, animals were randomized to either control (saline infusion, 5 monkeys) or treatment groups (intravenous NaNO(2) infusion at 300 μg/kg/hr for 3 hours [7 monkeys] or 8 hours [2 monkeys]). Arteriographic vessel diameter was blindly analyzed to determine the degree of vasospasm before, during, and after treatment. Nitric oxide metabolites (nitrite, nitrate, and S-nitrosothiols) were measured in whole blood and CSF., Results: Moderate-to-severe vasospasm was present in all animals before treatment (control, 36.2% ± 8.8% [mean ± SD]; treatment, 45.5% ± 12.5%; p = 0.9). While saline infusion did not reduce vasospasm, NaNO(2) infusion significantly reduced the degree of vasospasm (26.9% ± 7.6%; p = 0.008). Reversal of the vasospasm lasted more than 2 hours after cessation of the infusion and could be maintained with a prolonged infusion. Nitrite (peak value, 3.7 ± 2.1 μmol/L), nitrate (18.2 ± 5.3 μmol/L), and S-nitrosothiols (33.4 ± 11.4 nmol/L) increased significantly in whole blood, and nitrite increased significantly in CSF., Conclusions: These findings indicate that the intravenous infusion of NaNO(2) can reverse SAH-induced vasospasm in primates. Further, these findings indicate that a similar treatment paradigm could be useful in reversing cerebral vasospasm after aneurysmal SAH.

Using vascular heat-exchange controller implemented mild hypothermia treatment, the authors established the cerebral vasospasm model in which blood was injected twice into dog's foramen magnum; and it was discussed the influence of the concentration of endothelin-1 and NO in blood plasma and cerebrospinal fluid through continuing treatment of mild hypothermia at different times in secondary brain vasospasm model after subarachnoid hemorrhage. Thirty healthy mongrel dogs were randomly divided into five groups; artificial cerebrospinal fluid group (group A), normal temperature control group (group C), mild hypothermia 8 h group (group H1), mild hypothermia 16 h group (group H2), and mild hypothermia 32 h group (group H3). The authors injected the artificial CSF into dog's foramen magnum in group A while the other four groups were injected with autologous arterial blood. The normal group's temperature maintained 38.5°C. The authors set the temperature at 33.5°C in mild hypothermia groups and this was maintained for 8, 16, and 32 h, respectively. ET-1 and NO levels in the cerebrospinal fluid and plasma were assayed in each group on days 0, 7, 14, and 21. Then the changes of the diameter of blood vessels of cerebral basilar artery and overall performance categories score in each group through application of CT angiography were recorded. In the cerebral vasospasm model which was constructed by injecting the blood to dog twice, mild hypothermia treatment, through the application of vascular heat-exchange controller, could reduce cerebral vasospasm. It was observed that the duration of the mild hypothermia is directly proportional to the longer duration of the relieving of cerebral vasospasm. The reciprocal changes observed in the levels of ET-1 and NO in cerebrospinal fluid and plasma revealed that it might be possible to reduce the cerebral vasospasm by regulating the rising amplitude of ET-1 and the decrease in NO in CSF and plasma.

Dementia is defined as a clinical syndrome characterized by acquired loss of cognitive and emotional abilities, severe enough to interfere with daily functioning and quality of life. Event related potentials (ERP) are sensitive to task variables that relate to cognitive behavior. They might be altered in patients with disorders of cognition such as dementia. Application of the P300 ERP component to the study of cognitive disorders provides a means of quantifying the level of mental impairment. At high levels, nitric oxide (NO), which is produced by microglia due to induction of nitric oxide synthase (NOS), is neurotoxic and may play a role in neurodegeneration. In our study an attempt has been made to record ERP in patients of mild and moderate dementia and to correlate their findings with nitric oxide levels in CSF and serum. Twenty patients with dementia were selected as cases and 20 subjects as controls, which were further subdivided according to the age groups. Both dementia cases and controls were assessed by minimental state examination (MMSE) and clinical dementia rating scale (CDRS) for evaluating the degree of dementia. It was observed that the MMSE score was reduced in demented cases. P300 latency was significantly delayed in mild and moderate cases of dementia. However, no change was seen in NO levels of cerebrospinal fluid (CSF) and serum in dementia cases and controls. A negative correlation was found between MMSE and P300 latency. Hence we conclude that cognitive impairment in demented patients is reflected in P300 latency but not in NO levels in CSF and serum.

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.

Tetramethylpyrazine (TMP), an ingredient of Chinese herbal Szechwan lovage rhizome, shows vasorelaxant effect. Cerebral vasospasm (CVS) after subarachnoid hemorrhage (SAH) is associated with high mortality and morbidity. Here, we evaluated the effect of TMP in a model of CVS and sought to identify the underlying mechanisms of action. A rabbit SAH model was established by injection of the autoblood via cisterna magna. Cerebral blood flow and arterial diameter were measured by Transcranial Doppler (TCD) and Computed Tomography Angiography (CTA). Expression of eNOS and PDE-V in basilar artery (BA) was assessed by western blots. Levels of nitric oxide (NO) in plasma and cerebral spinal fluid, and of intra-endothelium Ca(2+) were measured. Significantly reduced diameter and accelerated blood flow velocity were detected in BAs of SAH animals (P<0.05 vs. sham group). Expression of eNOS and NO was increased, and PDE-V expression was reduced by TMP.TMP ameliorated cerebral vasospasm (P<0.05 vs. SAH group), and L-NAME (a NOS inhibitor) partly abrogated the effects of TMP. TMP induced a dose-dependent increase of intra-endothelium Ca(2+). The current results demonstrated that the vasorelaxant effect of TMP was at least in part via regulation of NO/cGMP signaling., (Copyright © 2010 Elsevier B.V. All rights reserved.)

The biological mechanisms associated with the development and rupture of intracranial aneurysms are not fully understood. To clarify the role of VEGF and the related receptors in the pathophysiology of aneurysm, immunostaining for VEGF, VEGFR1 and VEGFR2 was performed on specimens from six unruptured aneurysms and on two specimens of normal arteries wall as a control. The results were correlated with NO concentration of CSF collected during surgery from 8 patients affected by unruptured aneurysms and in 11 control patients. The immunohistochemical data showed a different pattern of VEGF/VEGFR1/VEGFR2 in aneurysms when compared with control. The results of this preliminary study suggest an imbalance of VEGF, VEGFR1 and VEGFR2, and the interaction of VEGF and NO in the pathophysiology of unruptured aneurysms. Our data support the hypothesis of aneurysm formation associated with a loss of expression of VEGFR1, moderate expression of VEGFR2 and high concentration of nitrate.

This study is to investigate the influence and mechanism of action of asymmetrical dimethylarginine (ADMA) and the induced oxidative stress level on Alzheimer's disease (AD) incidence. ADMA concentration, nitric oxide, Abeta(40)/Abeta(42) ratio, inducible NO synthase (iNOS) activity and the concentrations of the induced free radicals including malondialdehyde (MDA), 3-nitrotyrosine (3-NT) and peroxynitrite (ONOO-) in the cerebrospinal fluid (CSF) from 34 neurologically normal controls and 37 AD patients were quantitatively determined and statistically compared. The results showed that the ADMA concentration significantly decreased in AD patients, and it showed negative correlation with the NO, iNOS activity, and showed positive correlation with MMSE score. ADMA concentration was negatively correlated with Abeta(40)/Abeta(42) ratio (P<0.01) with the observation that Abeta(40)/Abeta(42) ratio increased while ADMA level decreased in CSF in AD patients. The concentration levels of MDA, 3-NT and ROS significantly increased compared with the control with all the P values less than 0.05. These findings suggested that the ADMA disorder and the oxidative damage effect of the induced free radicals in CSF of AD patients are an important mechanism of AD incidence, and their joint regulation may provide new idea for the prevention and clinical treatment of AD.

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.

Oxidative damage plays a role in neurodegenerative diseases. Levels of cerebrospinal fluid nitrite and nitrate levels (oxidation products that provide an indirect estimation of nitric oxide) were investigated in relation to clinical and laboratory features in subacute sclerosing panencephalitis (n = 47) and age-matched control (n = 43) groups. Significantly decreased levels of nitrite (median, 4.91 micromol/L) and nitrate (median, 6.14 micromol/L) were found in the patients. Nitrite and nitrate levels did not correlate with clinical or laboratory findings, except for presence of myoclonus. Cerebrospinal fluid nitrite levels of subacute sclerosing panencephalitis patients without myoclonic jerks were significantly higher than in those with myoclonus (median, 15.63 vs 4.34 micromol/L, respectively). The higher levels of nitrite in these patients can be explained by short disease duration and early stages of disease. Nitrate levels in subacute sclerosing panencephalitis patients with myoclonus (median, 9.26 micromol/L) were higher than in those without myoclonus (median, 4.25 micromol/L). Microbleeding resulting in conversion of nitrite to nitrate and increased production of superoxide can be suggested as possible mechanisms underlying these findings.

Study Design: Multiple center study to evaluate cerebrospinal fluid (CSF) concentrations of nitric oxide metabolites [NOx] in relation to neurologic severity and prognosis in spinal cord injury (SCI)., Objective: To examine whether CSF [NOx] correlates with neurologic severity and recovery in SCI., Summary of Background Data: Inducible nitric oxide synthase is expressed in rat spinal cord immediately after SCI. Excessive nitric oxide production is cytotoxic, causing neuronal apoptosis with subsequent neurodysfunction in the spinal cord. We previously reported a significant correlation between initial [NOx] after incomplete cervical cord injury (CCI) and neurologic recovery at the final follow-up in 25 cases., Methods: Ninety-six cases (SCI group), including 76 patients with CCI and 20 patients with thoracic cord injury were examined. Mean follow-up period was 11 months. The control group comprised 40 cases (3 healthy volunteers and 37 patients with neither pain nor neurologic disorders). CSF [NOx] were measured using the Griess method. Severity of neurologic impairment was assessed using Frankel's classification and the American Spinal Injury Association motor score (ASIA MS). Degree of neurologic recovery was assessed using Frankel's classification and the ASIA motor recovery percentage., Results: CSF [NOx] did not differ significantly among the control, CCI, and thoracic cord injury groups at the initial examination. In the CCI group, [NOx] in the Frankel A and B classes were significantly higher than [NOx] in the control group at 5 to 14 days, in the Frankel A and B classes at 0 to 4 days, and in the Frankel C and D classes at 5 to 14 days. Also, in the CCI group at 5 to 14 days, [NOx] correlated significantly with ASIA MS and motor recovery percentage., Conclusion: There was a significant correlation between CSF [NOx] at the pathologic early subacute stage (approximately 5-14 days) and neurologic severity and recovery in SCI.

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.

The understanding of oxidative damage in different neurodegenerative diseases could enhance therapeutic strategies. Our objective was to quantify lipoperoxidation and other oxidative products as well as the activity of antioxidant enzymes and cofactors in cerebrospinal fluid (CSF) samples. We recorded data from all new patients with a diagnosis of either one of the four most frequent neurodegenerative diseases: Parkinson's disease (PD), Alzheimer's disease (AD), Huntington's disease (HD) and lateral amyotrophic sclerosis (ALS). The sum of nitrites and nitrates as end products of nitric oxide (NO) were increased in the four degenerative diseases and fluorescent lipoperoxidation products in three (excepting ALS). A decreased Cu/Zn-dependent superoxide dismutase (SOD) activity characterized the four diseases. A significantly decreased ferroxidase activity was found in PD, HD and AD, agreeing with findings of iron deposition in these entities, while free copper was found to be increased in CSF and appeared to be a good biomarker of PD.

Background: The prevalence of HIV-associated neurocognitive disorders is increasing as HIV-infected individuals are living longer. The clinical manifestations of the syndrome also continue to evolve under the influence of antiretroviral drugs and comorbidities such as drugs of abuse. However, there are no surrogate markers for the disease, either to identify it de novo or to track its progression, and there is no proven treatment with the exception of antiretroviral drugs., Methods: Levels of nitric oxide, nitrate, and 3-nitrotyrosine (3-NT)-modified proteins were measured in the CSF of 46 patients with HIV infection stratified according to their neurocognitive status and history of IV drug use (IVD). The 3-NT-modified proteins were isolated and identified by tandem mass spectrometry, and the functional consequence of 3-NT modification of L-prostaglandin D synthase (L-PGDS), the most abundant protein, was determined., Results: 3-NT-modified proteins were significantly elevated in patients with HIV infection who had progressive neurocognitive decline over the next 6 months and in patients with a history of IVD. Thirteen different proteins with 3-NT modification were identified in the CSF of these patients. L-PGDS was the most abundant. 3-NT modification of this protein resulted in loss of its enzymatic activity., Conclusions: There is increased nitrosative stress in CSF of HIV-infected patients with active dementia and in patients with a history of IV drug use, measurement of which may serve as a surrogate marker for these patients. Nitrosative stress may also have important functional consequences and may impact the pathogenesis of HIV-associated neurocognitive disorders.

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.

Objective: To observe the variation of endothelin (ET) and nitric oxide (NO) in plasma and cerebrospinal fluid (CSF) in rabbits, and evaluate the effects of tetramethylpyrazine (TMP) on the prevention and cure of cerebral vasospasm (CVS) after subarachnoid hemorrhage (SAH)., Methods: 24 New Zealand rabbits were randomly assigned into three groups: contrast group, experiment group and blank group. Every group contained 8 rabbits. SAH was established according to inject blood into the cisterna magna. The experiment group was administrated with TMP (20 mg/kg x d) transperitoneally. ET and NO of plasma and CSF were detected by radical immunoassay at 72 h and 168 h after SAH. Neurofunction were detected in every group at all the time scales., Results: (1) After SAH, the level of ET in CSF increased significantly in contrast group compared with that in experiment and blank groups (P<0.05). The value of ET at 168 h was higher than that at 72 h. The level of ET in plasma increased significantly in contrast group compared with blank and experiment groups (P<0.05), and no significant contrast could be found between blank and experiment group. (2) After SAH, the value of NO in CSF was lower in contrast group than in other groups (P<0.05), and the level of NO in CSF continued to decrease in all groups on some extent. As time went by, no significant contrast could be found in all groups. The value of NO in plasma was lower in contrast group than in other groups (P<0.05). There was no significant difference between experiment and blank groups. (3) The neuro-function score continued to be increased in contrast group, but decreased in experiment one. The neuro-function score was lower in experiment group than in contrast one at every time point (P<0.05)., Conclusion: After administration of TMP, the variation of ET has the continued decrease in plasma and CSF; the variation of NO shows the continued increase in plasma and CSF; neurological function gets possibly protected. TMP may prevent from and cure CVS after SAH.

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.

Both nitric oxide and asymmetric dimethylarginine (ADMA) play a critical role in the regulation of cerebral blood flow, though their neuroprotective and cytotoxic effects are still under investigation. In this study, we found that nitrate/nitrite (NOx) levels in plasma, ischemic brain tissue, and cerebrospinal fluid (CSF) increased significantly 24h after 2h transient middle cerebral artery occlusion (MCAO) in rats. ADMA levels were unchanged in plasma, but decreased significantly in CSF 24h following MCAO. The CSF ADMA/NOx ratio decreased markedly following ischemia. Rats protected by expression of the chaperonin GroEL or its folding deficient mutant D87K had lower plasma NOx levels at 24h reperfusion. ADMA, NO, and their ratio in CSF merit further study as biomarkers for ischemic brain injury.

Background: The prevention of ischemic paraplegia after thoracoabdominal aortic surgery is challenging for both anesthesiologists and surgeons. In a previous study, we showed that intrathecal ketorolac pre-treatment protects rats against ischemic spinal cord injury. In the present study, using a microdialysis method, we investigated whether this neuroprotective effect was related to changes in the spinal cord release of nitric oxide (NO) or the excitatory amino acids (EAAs) aspartate and glutamate., Methods: Rats were randomized to receive either intrathecal saline or ketorolac 60 microg (10 rats per group), 1 h before spinal cord ischemic injury induced by balloon inflation of a 2F Fogarty catheter in the thoracic aorta with maintenance of the proximal arterial blood pressure at 40 mmHg for 11 min, followed by reperfusion. Another 10 animals were used as the sham-operated control group. Ischemic injury was assessed by hind limb motor function. Cerebrospinal fluid dialysates were collected at baseline (before ischemia) and at 1, 2, 3, 4, 6, 12 and 24 h after the start of reperfusion, and were analyzed for EAAs using high-performance liquid chromatography and for NO metabolites using an NO analyzer., Results: The results showed that intrathecal ketorolac attenuated spinal cord ischemic injury. Dialysate concentrations of NO and EAAs were increased after spinal cord ischemia, and this effect was inhibited by intrathecal administration of ketorolac., Conclusions: The results of this study suggest that the neuroprotective effect of intrathecal ketorolac in spinal cord ischemia in rats may be caused by a decrease in the spinal cord release of NO and EAAs.

This study aimed to investigate the effect of allopurinol in the management of cerebral hypoxia-ischemia by monitoring nitric oxide levels of serum and cerebrospinal fluid. Sixty asphyxiated infants were divided randomly into two groups. Group I infants (n = 30) received allopurinol (40 mg/kg/day, 3 days) within 2 hours after birth. Group II infants (n = 30) received a placebo. Twenty healthy neonates served as control subjects. Cerebrospinal fluid and serum nitric oxide levels were measured within 0-24 hours and 72-96 hours after birth. Both serum and cerebrospinal fluid concentrations of nitric oxide were higher in severely asphyxiated infants (40.86 +/- 8.97, 17.3 +/- 3.63 micromol/L, respectively) but lower in mildly asphyxiated infants (25.85 +/- 3.57, 5.70 +/- 2.56 micromol/L, respectively) than in moderately asphyxiated infants (35.86 +/- 5.38, 11.06 +/- 3.37 micromol/L, respectively) within the first 0-24 hours after birth. Serum nitric oxide levels in control subjects were lower than those of moderately and severely asphyxiated infants. Serum nitric oxide levels of Group I infants within 72-96 hours after birth decreased significantly from their corresponding levels within 0-24 hours after birth. The asphyxiated newborns treated with allopurinol had better neurologic and neurodevelopmental outcome at 12 or more months of age.

Evidence from clinical and experimental studies supports the hypothesis of free radical-mediated damage of dopaminergic neurons in the pathology of Parkin's disease (PD). The present study was undertaken to evaluate the role of nitric oxide and oxidative stress in PD. Estimation of the stable metabolites of nitric oxide (NO, nitrite, nitrate) and malondialdehyde (MDA), an acceptable marker of lipid peroxidation, can provide indirect evidence of involvement of free radicals. Nitrite and malondialdehyde (MDA) levels were estimated in the lumbar cerebrospinal fluid (CSF) of 20 controls and 21 patients with PD. Nitrite and MDA content was not significantly altered in the CSF of PD patients as compared to the controls. Nitrite and MDA levels in CSF of PD patients exhibited no correlation with age, duration of disease, and severity of illness (measured by the Unified Parkinson's Disease Rating Score). There was no correlation between the CSF nitrite and MDA level. Findings of the present study do not provide evidence for the involvement of nitric oxide and oxidative stress in PD.

We investigated the time course of changes in nitric oxide metabolite (NO2- plus NO3-: NOx) levels in the cerebrospinal fluid and the expression of local inducible nitric oxide synthase following cauda equina compression in rats. Cerebrospinal fluid NOx levels were significantly increased from 12 h to 3 days after compression, and decreased thereafter. Histologically, inducible nitric oxide synthase immunoreactivity was observed in macrophages that infiltrated the dura mater on days 1 and 3 after compression, but not in foamy macrophages in the parenchyma of the cauda equina observed afterwards. The pattern of NOx levels coincided with the appearance of inducible nitric oxide synthase labeled macrophages, indicating a critical role of these cells as the main synthesizers of NOx in the acute stage of cauda equina compression.

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.

This study analyzes the relationship between amino acids and pain perception during active labor. Cerebrospinal fluid (CSF) levels of the excitatory amino acids (EAAs)-glutamate, aspartate and their amide forms, inhibitory amino acids (IAAs)-glycine, gamma-amino butyric acid (GABA) and taurine and nitric oxide (NO) related compounds-arginine and citrulline (by-product of NO synthesis) were compared between pregnant women at term pregnancy with labor pain (n = 38) and without labor pain (Caesarian section; n = 30). The levels of aspartate, glycine, GABA and citrulline were significantly higher; whilst taurine was significantly lower in the labor pain group. These findings suggest that aspartate and NO are associated with labor pain. An inhibitory role for the IAA taurine and a pronociceptive role for glycine in labor pain are proposed.

Brain injury, like other central nervous system pathologies, causes changes in the composition of the cerebrospinal fluid (CSF). In this study, changes in the concentration of small molecules of the CSF, which are in the minimal micromolar concentration, were observed and monitored using high-resolution proton (NMR) spectroscopy. Twenty-two patients with isolated traumatic brain injuries (TBI) and 15 patients making up the control group were recruited for the study. CSF samples were collected by lumbar puncture from the lumbar subarachnoid space in the patients just before commencement of therapy and on the first, third, seventh and fourteenth days of therapy at the ICU. Forty-four signals of the NMR spectra and NO concentration of the CSF samples were analyzed. The analysis shows that the amino acid and organic acid concentrations change during the therapy and mostly are higher than in the control group. Significant differences in concentration of the analyzed CSF components between the TBI patients and the control group have been noted. The rate of the lactate to pyruvate conversion increased because the L/P ratio showed no significant differences between the TBI group and the control group, while the concentrations of both components were significantly higher in the TBI patients than in the control group. Citrulline, arginine and nitric oxide concentrations were the focus of the analysis. Citrulline concentration changes overlapped NO changes from 0 until 3rd day of therapy, while for the remaining days of observation the NO concentration stabilized at the control level, whereas citrulline concentration significantly decreased.

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.

It has been reported that active oxygen and/or free radicals are produced in the central nervous system (CNS) compartment in patients with bacterial meningitis, so it is supposed that the levels of endogenous antioxidative scavengers in the cerebrospinal fluid (CSF) are elevated as an adaptive reaction to bacterial meningitis, which exerts severe stress on the human body. We assumed that they are also elevated in patients with convulsive diseases. Nitric oxide (NO) and endogenous antioxidative scavengers (glutathione (GSH), glutathione peroxidase (GPX), (total) superoxide dismutase (T-SOD), manganese superoxide dismutase (Mn-SOD), and catalase) were measured in CSF from a group of child patients with various neurological diseases and a control group. NO, GSH, and GPX activities in CSF from the patients with convulsive diseases were significantly higher than in those with aseptic meningitis or in the controls. Furthermore, all parameters in CSF from patients with bacterial meningitis were significantly higher than in any other group. The present study suggests that oxidative stress may be associated with the pathophysiology of convulsion and that its clinical attenuation will lead to improvement in the prognosis for convulsive diseases.

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.

We have reported recently that intrathecal (i.t.) injection of interleukin-1beta (IL-1beta), at a dose of 100 ng, induces inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production in the spinal cord and results in thermal hyperalgesia in rats. This study further examines the role of mitogen-activated protein kinase (MAPK) in i.t. IL-1beta-mediated iNOS-NO cascade in spinal nociceptive signal transduction. All rats were implanted with an i.t. catheter either with or without an additional microdialysis probe. Paw withdrawal latency to radiant heat is used to assess thermal hyperalgesia. The iNOS and MAPK protein expression in the spinal cord dorsal horn were examined by western blot. The [NO] in CSF dialysates were also measured. Intrathecal IL-1beta leads to a time-dependent up-regulation of phosphorylated p38 (p-p38) MAPK protein expression in the spinal cord 30-240 min following IL-1beta injection (i.t.). However, neither the phosphorylated extracellular signal-regulated kinase (p-ERK) nor phosphorylated c-Jun NH2-terminal kinase (p-JNK) was affected. The total amount of p38, ERK, and JNK MAPK proteins were not affected following IL-1beta injection. Intrathecal administration of either selective p38 MAPK, or JNK, or ERK inhibitor alone did not affect the thermal nociceptive threshold or iNOS protein expression in the spinal cord. However, pretreatment with a p38 MAPK inhibitor significantly reduced the IL-1beta-induced p-p38 MAPK expression by 38-49%, and nearly completely blocked the subsequent iNOS expression (reduction by 86.6%), NO production, and thermal hyperalgesia. In contrast, both ERK and JNK inhibitor pretreatments only partially (approximately 50%) inhibited the IL-1beta-induced iNOS expression in the spinal cord. Our results suggest that p38 MAPK plays a pivotal role in i.t. IL-1beta-induced spinal sensitization and nociceptive signal transduction.

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.