Fluid Nitric Oxide Metabolites Research Articles

Levodopa-induced dyskinesias in Parkinson's disease increase cerebrospinal fluid nitric oxide metabolites' levels.

Levodopa-induced dyskinesia (LID) is a common complication of Parkinson's disease (PD) therapy. Nitric oxide in the central nervous system may have a role in its pathophysiology. The present work investigates plasma and CSF levels of nitric oxide metabolites nitrite and nitrate in patients with PD, LID, and healthy control. We measured plasma and CSF nitrite and nitrate levels in patients with PD with and without LID and in healthy controls. The levels of plasma and CSF nitrite and nitrate were measured by ozone-based chemiluminescence. Sixty-seven participants were enrolled. CSF nitrite levels in patients with PD and LID were higher than in patients with PD without LID and healthy controls. CSF/plasma ratio of nitrite was higher in patients with PD and LID than in patients with PD without LID. The CSF/plasma ratio of nitrite in patients with PD and LID was higher than 1, indicating an intrathecal production of NO in patients with this motor complication. There was an increase in nitrate levels of CSF and CSF/plasma ratio of nitrate in patients with PD and LID compared to the healthy controls. Sex, age at evaluation, disease duration, and levodopa equivalent daily doses, as well as processing and storage time, did not critically influence these results. The present study demonstrated an increase in nitrite and nitrate levels in the central nervous system of patients with PD and LID. This finding strengthens the role of NO on LID pathophysiology.

Nitric Oxide Metabolite Concentration in Cerebrospinal Fluid: Useful as a Prognostic Marker?

Study DesignProspective study.PurposeTo establish the significance of cerebrospinal fluid (CSF) nitric oxide metabolite (NOx) concentration in acute spinal cord injury (SCI) patients to assess the neurological severity and prognosis.Overview of LiteratureQuantitative analysis of specific biomarkers in CSF will assess neurological severity more accurately and permit the formulation of a more precise management plan.MethodsForty SCI patients represented the cases and 20 lower limb injury patients were the controls. NOx concentration in CSF was measured at week 1, 2, and 4 by Griess method. Magnetic resonance imaging (MRI, T2-weighted) done in each case to measure cord edema and neurological severity was assessed using the Frankel classification.ResultsCSF NOx concentration peaked at week 2 and declined to normal by week 4. The concentration remained normal in controls. Mean NOx concentration was directly proportional to the severity of acute SCI as correlated with cord edema seen in MRI and neurological severity assessed.ConclusionsCSF NOx concentration can be considered a specific quantitative biomarker in acute stage of SCI to predict the severity and prognosis of SCI patients.

Cerebrospinal fluid nitric oxide metabolite levels as a biomarker in severe traumatic brain injury

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.

High-risk human papillomavirus-induced expression of endothelial and inducible nitric oxide synthase in human uterine cervix

Introduction. Levels of nitric oxide metabolites are elevated in the cervical fluid of women with high-risk human papillomavirus (hrHPV). To elucidate the origin of this elevation we studied the cervical expression and localization of endothelial and inducible nitric oxide synthases (eNOS, iNOS) in women. Material and methods. Expression of eNOS and iNOS was studied by Western blotting in the uterine cervixes of 86 women with (n = 41) and without (n = 45) hrHPV infection. The localization of eNOS and iNOS in cervical cells was studied by immunohistochemistry in 32 randomly selected women. Results. Expression of eNOS and iNOS (in mean [95% CI] density units relative to actin) was higher in women with hrHPV versus those without (eNOS: 33.8 [22.5–45.1] versus 20.2 [6.1–34.3], P = 0.007; iNOS: 12.0 [7.1–16.9]) versus 5.6 [2.0–9.2], P = 0.003). Smoking reduced 64% eNOS (P = 0.001) and 68% iNOS (P = 0.008) in women with hrHPV. Endothelial NOS was localized in the vascular endothelium, while iNOS was present in basal squamous epithelial cells. Low-grade histological lesions were accompanied by elevated expression of both eNOS and iNOS. Conclusions. High-risk HPV-associated elevation in cervical fluid nitric oxide metabolites results from both eNOS and iNOS stimulation. However, smoking seems to suppress this stimulation in hrHPV-infected women.

The Prognostic Value of Brain Extracellular Fluid Nitric Oxide Metabolites After Traumatic Brain Injury

Nitric oxide (NO) is a compound with both protective and damaging effects on neurons. Quantification of NO metabolites in humans is limited by sample contamination with blood. In vivo cerebral microdialysis may offer an alternative approach as sampling of extracellular fluid (ECF) adjacent to neurons becomes possible. We investigate the prognostic value of brain ECF NO metabolites in patients with traumatic brain injury (TBI). A prospective case cohort of 195 ECF samples collected from 11 cases over 4 days following TBI was collected. Nitrate and nitrite concentrations ([NO x ]) were quantified using a vanadium-based colorimetric assay. Early ECF [NO x ] (<48 h post TBI) were significantly higher in non-survivors (median 59.2 μmol/l, n = 7) compared to survivors (23.3 μmol/l, n = 4) (P = 0.04). Late (48-96 h) ECF [NO x ] remained higher in non-survivors (47.9 μmol/l) compared to survivors (23.0 μmol/l) but this was not significant (P = 0.29). Receiver operator characteristic analysis shows an optimized cutoff level for ECF [NO x ] of 26.5 μmol/l measured <48 h post TBI for predicting non-survival (sensitivity 100%, specificity 75%). Early ECF NO x concentrations are of prognostic value after TBI. ECF NO x may be a useful biomarker for treatment trials targeted at nitric oxide metabolism.

Cervical nitric oxide release in Chlamydia trachomatis and high-risk human papillomavirus infection

To compare cervical fluid nitric oxide release in women with and without Chlamydia trachomatis and high-risk human papillomavirus infection (hrHPV). An open clinical study. University Hospital of Helsinki. Thirty-nine women with (n=21) and without C. trachomatis (n=18). Chlamydia trachomatis and/or hrHPV were studied by using specific RNA- and DNA-based tests. Levels of cervical fluid nitric oxide metabolite (NOx) were assessed by the Griess reaction. The difference in cervical fluid NOx between women with and without C. trachomatis and hrHPV. Fourteen (67%) C. trachomatis-infected women and three (17%) noninfected women had concomitant hrHPV. The level of cervical fluid NOx in women with C. trachomatis (median 37.5 μmol/l, 95% confidence interval 26.1-50.9) was higher (p=0.02) than that in C. trachomatis-noninfected women (median 19.7 μmol/L, 95% confidence interval 5.6-30.0). The presence of hrHPV did not associate with any difference in NOx levels between C. trachomatis-infected or -noninfected women. Chlamydia trachomatis was associated with increased release of nitric oxide metabolites in the uterine cervix. This stimulus was stronger than that of hrHPV, because no additional rise in NOx was seen in women with concomitant C. trachomatis and hrHPV infection.

Cervical nitric oxide release and persistence of high-risk human papillomavirus in women

Nitric oxide may serve as one cofactor for human papillomavirus (HPV)-induced development of cervical cancer. Therefore, we first assessed the levels of cervical fluid nitric oxide metabolite (NOx) in 283 women with and without high-risk (hr) HPV. The NOx level in women with hr HPV (48.4 μmol/L [95% CI: 39.4-56.6], n = 199) was higher (p < 0.001) than that in women without hr HPV (24.6 μmol/L [95% CI: 19.1-38.7], n = 84). Second, we evaluated if cervical fluid NOx levels could predict the persistence of hr HPV. Therefore, we followed up 113 women with detectable hr HPV without any treatment for 12 mo and repeated hr HPV test. High-risk HPV persisted in 72 women (64%) and disappeared in 41 women (36%). The median basal levels of NOx were higher (p = 0.02) in women with persistent hr HPV (56.9 μmol/L [95% CI: 48.7-81.0]) compared to those with eradicated hr HPV (37.7 μmol/L [95% CI: 27.0-58.0]). The NOx level higher than the 75th percentile (>87.0 μmol/L) predicted hr HPV persistence (OR = 4.1 [95% CI: 1.3-13.1]). This cutoff level of NOx showed 33% sensitivity and 90% specificity in predicting the persistence of hr HPV, but it failed to predict cytological progression or regression in 12 mo. In conclusion, high cervical fluid NOx appears to be connected to the persistence of hr HPV, but the low predictive capacity of NOx prevents its clinical use at this phase.

Misoprostol induces cervical nitric oxide release in pregnant, but not in nonpregnant, women

The cells of the human uterine cervix synthesize nitric oxide, which may be a factor in cervical ripening. We studied the effect of misoprostol on cervical nitric oxide release in nonpregnant and pregnant women. Seventy-two nonpregnant (n=15) and pregnant (n=57; 26 in early pregnancy, 31 in late pregnancy) women were treated with either vaginal misoprostol (n=54) or vaginal placebo (n=18). The dose of misoprostol was 400 mug in nonpregnant and early pregnancy group, and 25 mug in late pregnancy group. Serial cervical fluid samples, collected before and up to 3 hours after misoprostol/placebo, were assessed for the concentration of nitric oxide metabolites by means of the Griess reaction. Placebo had no effect on cervical fluid nitric oxide metabolite level. In 1 to 3 hours, misoprostol induced 4.3- to 5.2-fold elevations in cervical fluid Nox concentrations in early pregnancy (P < .01), and 4.4- to 18.2-fold elevations in late pregnancy (P < .01), but these responses did not differ significantly from each other. Misoprostol had no effect on cervical fluid nitric oxide metabolites in nonpregnant women. There was a trend towards a relationship between cervical nitric oxide stimulation after misoprostol and cervical ripening. Vaginal misoprostol stimulates cervical nitric oxide release in pregnancy. This suggests a joint action of nitric oxide and prostaglandins in cervical ripening.

Nitric oxide in ascitic fluid is an independent predictor of the development of renal impairment in patients with cirrhosis and spontaneous bacterial peritonitis.

Cirrhotic patients with spontaneous bacterial peritonitis show a marked activation of the cytokine cascade, and cytokines induce the synthesis of nitric oxide in vitro. Our aim was to assess whether patients with ascitic fluid infection show increased levels of nitric oxide, and whether this is related to the development of renal impairment. Retrospective analysis of prospectively collected specimens from 168 patients with cirrhosis and presence of sterile or infected ascitic fluid. Routine biochemical data together with nitric oxide metabolites, tumour necrosis factor and interleukin-6 were measured. Univariate and multivariate analyses were performed to identify factors related to the development of renal impairment. Patients with infected ascites showed increased serum and ascitic-fluid levels of nitric oxide metabolites and cytokines compared with patients with sterile ascites. A significant direct correlation was observed between serum and ascitic fluid nitric oxide metabolite levels. Multivariate analysis identified ascitic-fluid nitric oxide metabolites as an independent predictor of renal impairment. The increased serum and ascitic fluid nitric oxide found in patients with infected ascites might induce a deterioration of the increased peripheral vasodilation found in this setting, leading to the development of renal impairment in a series of patients with spontaneous bacterial peritonitis.

Cervical nitric oxide release in women postterm.

Nitric oxide may be a factor in cervical ripening. We compared the nitric oxide metabolite levels in cervical fluid in women going beyond term and in women delivering spontaneously at term. We studied a total of 208 women with singleton pregnancies: 108 women who went beyond term (294 days or longer), and 100 women who went spontaneously into labor at term. Cervical fluid samples, collected well before the initiation of labor, were assessed for nitric oxide metabolites using an assay with a detection limit of 3.8 micromol/L. Women going beyond term had detectable levels of nitric oxide metabolites in their cervical fluid (60%) less often (P =.001) than women delivering at term (87%). The nitric oxide metabolite concentration in cervical fluid in women going beyond term (median 23.5 micromol/L; 95% confidence interval less than 3.8, 31.8) was 4.5 times lower (P <.001) than that in women delivering at term (median 106.0 micromol/L; 95% confidence interval 81.8, 135.0). Such a difference (14.0 versus 106.0 micromol/L) also existed when only the 66 women going into spontaneous postterm labor were included in the comparison. Both nulliparous (median less than 3.8 micromol/L) and parous (median 31.3 micromol/L) women going beyond term had lower (P <.01) cervical fluid nitric oxide metabolite levels than nulliparous and parous women delivering at term (medians 76.1 and 101.3 micromol/L, respectively). In the postterm group, women with cervical fluid nitric oxide metabolite concentrations at or below the median failed more often (P <.001) to progress in labor and had longer (P =.02) duration of labor than those with cervical fluid nitric oxide metabolite concentrations above the median. Reduced cervical nitric oxide release may contribute to prolonged pregnancy. II-2

Nitric oxide metabolites in cervical fluid during pregnancy: Further evidence for the role of cervical nitric oxide in cervical ripening

Objective: Cervical tissue expresses all the isoenzymes of nitric oxide synthase. We studied the concentrations of nitric oxide metabolites in the cervical fluid in nonpregnant (n = 11) and pregnant women (n = 106). Study Design: Cervical fluid was collected into a Dacron polyester swab, and nitric oxide metabolites were eluted into physiologic saline solution, which was assayed for nitric oxide metabolites with the Griess reaction. The detection limit of the method is 0.2 μmol/L. Results: Cervical fluid nitric oxide metabolite was detectable in 46% of nonpregnant women (median, <0.2 μmol/L; 95% CI, 0-49), in 63% of women in early pregnancy (median, 11 μmol/L; 95% CI, 0-23) and in 82% of women in late pregnancy (median, 128 μmol/L; 95% CI, 21-276). In late pregnancy, the cervical fluid nitric oxide metabolite level was higher in women with Bishop score of ≥6 (median, 163 μmol/L; 95% CI, 105-276) than in women with Bishop score of <6 (median, 86 μmol/L; 95% CI, 21-99). Cervical fluid nitric oxide metabolite concentration before the onset of labor in parous women (median, 97 μmol/L; 95% CI, 78-283) was higher (P =.008) than that in nulliparous women (median, 28 μmol/L; 95% CI, 0-95). Cervical fluid nitric oxide metabolites before the initiation of labor (median, 33 μmol/L; 95% CI, 0-95) rose to 3.5-fold (median, 115 μmol/L; 95% CI, 78-284) after the commencement of uterine contractions and showed a significant relationship to Bishop score (r = 0.39, P =.01). Cervical fluid nitric oxide metabolite concentrations were not relative to simultaneous plasma nitric oxide metabolite levels (n = 41 women, r = 0.14, P =.41). Rupture of fetal membranes tended to decrease cervical fluid nitric oxide metabolite levels, whereas gentle cervical manipulation elevated it 6.6-fold in 1 minute. The administration of glyceryl trinitrate (0.5 mg, nitric oxide donor) intracervically resulted in a significant rise in the cervical fluid nitric oxide metabolite level in 2 minutes. Conclusion: Cervical fluid nitric oxide metabolite level rises after cervical ripening, nitric oxide donor administration, or cervical manipulation, which supports a role for cervical nitric oxide in cervical ripening. (Am J Obstet Gynecol 2003;188:779-85.)

Cerebrospinal fluid nitric oxide metabolites are novel predictors of pain relief in degenerative lumbar diseases

This study was undertaken to determine whether or not nitric oxide metabolites (NO2− plus NO3−: NOx levels) in cerebrospinal fluid (CSF) would be predictors of treatment outcome in patients with degenerative lumbar diseases (DLD) including lumbar disc herniation (LDH) and lumbar spinal canal stenosis (LCS). The NOx levels in CSF were measured using an NO analyzer based on the Griess method. Six healthy volunteers and 18 patients with painless diseases were included in the control group. The pre- and postoperative NOx levels in 25 DLD patients, who underwent herniotomy for LDH (17 patients) or selective decompression for LCS (eight patients), were analyzed. The postoperative follow-up periods were approximately 8 months. Nineteen of 25 DLD patients, whose preoperative NOx levels were two standard deviations higher than the mean NOx levels of an age-matched control group, were included in an NO elevated (NOE) group. Among the 25 DLD patients, the preoperative NOx levels in six patients (young LDH group) were within the normal range. The pain-related Japanese Orthopaedic Association score and the Hirabayashi recovery rate were respectively used to evaluate the pain severity and the degree of pain relief. The preoperative and changes of postoperative NOx levels in the NOE group were negatively correlated with the Hirabayashi recovery rate. Normal postoperative NOx levels and excellent pain relief were achieved in young DLD patients. In conclusion, the preoperative and changes in postoperative NOx levels are quantitative predictors of postoperative pain relief in DLD patients.

Amniotic fluid nitric oxide metabolite levels and nitric oxide synthase localization in feto-placental tissues are modified in association with human labor

Nitric oxide (NO) has a relaxant effect on uterine smooth muscle and may be implicated in maintaining uterine quiescence during pregnancy. In order to investigate the role of nitric oxide in human parturition, we have measured NO metabolite levels in maternal and fetal compartments in association with labor, both at term and preterm. We have also examined the localization and distribution of NO synthase (NOS) isoforms in placentas and fetal membranes after term and preterm delivery by means of immunohistochemistry. Although no differences were present in maternal and fetal blood and in maternal urine among groups, we found that NO metabolite concentrations were higher in amniotic fluid collected from women in labor than in non-laboring patients, both at term (15.4±1.6 vs. 6.8±0.6 μM/mg creatinine) and preterm (16.7±2.0 vs. 7.0±0.8 μM/mg creatinine). Ir-bNOS staining appeared to be decreased in fetal membranes collected after spontaneous labor at term and preterm. In contrast, a stronger staining for iNOS was detected in trophoblast cells of fetal membranes from women in labor than in those from non-laboring women. We suggest that NOS isoenzymes in fetal placental tissues are differently regulated and might play different roles during pregnancy.

Amniotic fluid nitric oxide metabolites, cyclic guanosine 3′,5′ monophosphate and dimethylarginine in alloimmunized pregnancies

Objective: To determine the relationship between gestational age or the Liley index (the severity of fetal hemolysis) and the amniotic fluid total nitrite (NOx), cyclic guanosine 3′,5 ′monophosphate (cGMP) and dimethylarginine (DMA) concentrations. We hypothesized that the concentrations of these components change because of fetal growth or adaptation to fetal anemia. Study Design: Amniotic fluids ( n=64) were obtained between 23 and 37 weeks from fifty-three patients at risk for alloimmunization. Amniotic fluids from the pregnancies with a Liley index=1 were considered as controls ( n=17). Creatinine (C, μMol) was determined with the Jaffé reagent, nitrite (NOx, μMol) with the Griess reagent, cGMP (nMol) by an enzyme immunoassay and DMA (μMol) after HPLC. Multiple regression analysis was used for separating the effects of growth and the estimated degree of anemia. Results: The concentration of NOx, cGMP and DMA was not related to the Liley index or whether or not the fetuses needed blood transfusions. The concentrations of creatinine (C), NOx and cGMP increased during pregnancy (in weeks;W) (C=−69.2+6.28W; r 2=0.532; P<0.0001, NOx=−17.6+ 1.29W; r 2=0.106; P=0.01, cGMP=−20.9+1.05W; r 2=0.414; P<0.0001). The DMA concentration (3.8±0.8(SD) and the NOx/creatinine ratio (181±110 mM/M) did not change with gestational age. The cGMP/creatinine ratios (μM/M) increased (cGMP/C=−41.8+4.31W; r 2=0.134; P=0.007) whereas the DMA/creatinine ratio (mM/M) declined during pregnancy (DMA/C=73.1−1.34W; r 2=0.278; P=0.0002). Consequently, the NOx/DMA and cGMP/DMA ratios increased (NOx/DMA=−6.96+0.43W; r 2=0.105; P=0.02, cGMP/DMA=−5.9+0.29W ; r 2=0.391; P<0.0001). Conclusions: The concentrations in amniotic fluid of cGMP and NOX, but not of DMA increase during gestation. The cGMP/creatinine ratio increases also whereas that of DMA decreases. The changes in products of the NO–cGMP pathway are independent of mild to moderate fetal hemolysis and may result from fetal growth as well as from reduced inhibition of NO synthase by DMA. Gestational age related effects should be taken into account when analyzing nitric oxide metabolites in amniotic fluids.

Cerebrospinal fluid nitric oxide metabolites in painful diseases.

To elucidate the involvement of NO in pain transmission in humans, we measured NO metabolites (nitrite/nitrate) in the CSF of patients with painful diseases using an NO analyzer based on the Griess method. The nitrite/nitrate levels in patients with degenerative lumbar disease (DLD), but not those with fracture or appendicitis, were significantly higher than those in an age-matched control group. The duration of pain in the DLD group was much longer than that in the fracture or appendicitis group. The nitrite/nitrate levels in the middle-aged and elderly DLD patients depended on the duration of pain. These data probably suggest that the duration of pain is critical for the elevation in nitrite/nitrate levels.

Nitric oxide: a clinically important amniotic fluid marker to distinguish between intra-amniotic mycoplasma and non-mycoplasma infections.

The objective of this study was to determine whether the measurements of amniotic fluid nitric oxide metabolite (NOx: nitrate + nitrite) concentrations could be a clinically useful marker to differentiate between intra-amniotic mycoplasma and nonmycoplasma infections. Amniocentesis was performed on 76 pregnant women with suspicion of intra-amniotic infection. Intra-amniotic infection was defined as the presence of a positive amniotic fluid culture with either mycoplasma or nonmycoplasma infections. Rapid amniotic fluid tests for Gram stain, glucose, leukocyte counts, interleukin-6, and NOx were performed. Amniotic fluid NOx was measured with aspergillus nitrate reductase and Griess reagent. Interleukin-6 was determined by enzyme immunoassays. Amniotic fluid NOx and interleukin-6 were normalized by amniotic fluid creatinine levels. Patients with intra-amniotic mycoplasma (n = 7) and nonmycoplasma infections (n = 8) had significantly higher amniotic fluid leukocyte counts and interleukin-6 concentrations and significantly lower amniotic fluid glucose levels than noninfected controls (n = 61). Amniotic fluid concentrations of NOx were significantly higher in those with intraamniotic nonmycoplasma infection as compared to those with intraamniotic mycoplasma infection and noninfected controls (NOx: 3.35+/-0.74 vs. 2.03+/-0.41 micromol/mg creatinine, p = 0.005, and 3.35+/-0.74 vs. 1.72+/-0.07 micromol/mg creatinine, p < 0.0001, respectively). However, patients with intra-amniotic mycoplasma infection did not differ significantly from noninfected controls. Our data indicate that clinical characteristics of intra-amniotic mycoplasma infection may differ from intra-amniotic nonmycoplasma infection. As delivery is not always indicated in intra-amniotic mycoplasma infection, elevated rapid amniotic fluid tests (leukocyte counts, interleukin-6, and glucose) may not be appropriate in the clinical management of intra-amniotic mycoplasma infection. In addition to these rapid amniotic fluid tests, incorporation of the measurement of amniotic fluid NOx may be of clinical importance in the differentiation and management of patients with suspected intra-amniotic mycoplasma and nonmycoplasma infection.

Cerebrospinal fluid and serum nitric oxide metabolites in patients with multiple sclerosis

Cerebrospinal fluid and serum nitric oxide metabolites in patients with multiple sclerosis

Elevated amniotic fluid nitric oxide metabolites and cyclic guanosine 3′,5′-monophosphate in pregnant women with intraamniotic infection

OBJECTIVE: Our purpose was to compare amniotic fluid nitric oxide metabolites and cyclic guanosine 3′,5′-monophosphate in pregnant women with and without intraamniotic infection. STUDY DESIGN: Amniocentesis was performed on 72 pregnant women with preterm contractions, labor, or rupture of membranes. Fourteen patients had intraamniotic infection and 58 did not. Intraamniotic infection was defined as the presence of a positive amniotic fluid culture. Amniotic fluid Gram stain, glucose, leukocyte counts, leukocyte esterase activity, creatinine, pH, and specific gravity were performed. Endogenous nitrite was determined using Griess reagent. Amniotic fluid nitric oxide metabolites (nitrite and nitrate) were measured after reduction of nitrate to nitrite with Aspergillus nitrate reductase. Tests for amniotic fluid cyclic guanosine monophosphate levels were determined by enzyme immunoassay. Two-tailed t test, contingency table methods, linear regression, and correlation were used for statistical analyses. RESULTS: Amniotic fluid levels of nitric oxide metabolites, endogenous nitrite, nitrate, and cyclic guanosine monophosphate were significantly higher in pregnant women with intraamniotic infection than in those without intraamniotic infection (2.66 ± 0.49 vs 1.77 ± 0.07 μmol/mg creatinine, p = 0.002; 0.69 ± 0.15 vs 0.38 ± 0.03 μmol/mg creatinine, p = 0.003; 1.99 ± 0.41 vs 1.38 ± 0.07 μmol/mg creatinine, p = 0.02; and 1.47 ± 0.22 vs 0.90 ± 0.08 nmol/mg creatinine, p = 0.004, respectively). Both amniotic fluid nitric oxide metabolites and cyclic guanosine monophosphate were positively correlated with amniotic fluid leukocyte counts and leukocyte esterase activity and negatively correlated with amniotic fluid glucose concentrations. CONCLUSIONS: Our data indicate that amniotic fluid nitric oxide and cyclic guanosine monophosphate may play important roles in the pathogenesis of intraamniotic infection. Measurements of amniotic fluid nitric oxide metabolites and cyclic guanosine monophosphate may be part of a panel of tests that can be used to detect intraamniotic infection. (Am J Obstet Gynecol 1997;177:793-6.)

Exchange of proteins between blood and spinal subarachnoid fluid.

ARTICLESExchange of proteins between blood and spinal subarachnoid fluidGM Hochwald, MC Wallenstein, and ES MathewsGM Hochwald, MC Wallenstein, and ES MathewsPublished Online:01 Aug 1969https://doi.org/10.1152/ajplegacy.1969.217.2.348MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInEmailWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformationCited ByReceptor-mediated transfer of IgG and albumin at cerebrospinal fluid interfaces3 January 2015 | Journal of Neural Transmission, Vol. 122, No. 9The preanalytic phase in veterinary clinical pathology1 December 2014 | Veterinary Clinical Pathology, Vol. 44, No. 1Cerebrospinal FluidInflammatory cerebrospinal fluid analysis in cats: Clinical diagnosis and outcome6 January 2017 | Journal of Feline Medicine and Surgery, Vol. 7, No. 2Cerebrospinal fluid nitric oxide metabolites in painful diseasesNeuroReport, Vol. 10, No. 2Cerebrospinal FluidMeasurement of Prostaglandins in the Cerebrospinal Fluid in Cat, Dog, and ManJournal of Neurochemistry, Vol. 43, No. 6Gradiente ventrículo-lombar de concentração das proteínas totais do líquido cefalorraquiano: 1 - Mecanismo de origemArquivos de Neuro-Psiquiatria, Vol. 41, No. 3Passage of Proteins from Blood to Cerebrospinal FluidAcquired hydrocephalusActa Neurochirurgica, Vol. 48, No. 3-4On the cerebral origin of 5-hydroxyindoleacetic acid in the lumbar cerebrospinal fluidBrain Research, Vol. 122, No. 2Sodium exchange between blood, brain, and CSF in normal and hydrocephalic catsJournal of Neuroscience Research, Vol. 3, No. 4Penetration of Proteins in the Central Nervous System8 March 2013CEREBROSPINAL FLUID PHOSPHOLIPIDS: Quantitative Determination of Fractionated Phospholipids and Normal Values in the Cerebrospinal Fluid29 January 2009 | Acta Neurologica Scandinavica, Vol. 49, No. 5Transport of proteins across normal cerebral arteriolesThe Journal of Comparative Neurology, Vol. 152, No. 1The Blood–Brain BarrierVariations in protein permeability in different regions of the cerebrospinal fluidExperimental Neurology, Vol. 28, No. 2Influx of serum proteins and their concentration in spinal fluid along the neuraxisJournal of the Neurological Sciences, Vol. 10, No. 3 More from this issue > Volume 217Issue 2August 1969Pages 348-353 Copyright & PermissionsCopyright © 1969 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1969.217.2.348PubMed4184005History Published online 1 August 1969 Published in print 1 August 1969 Metrics