Effect of external sleep disturbance on sleep architecture in perimenopausal and postmenopausal women.

OBJECTIVE: This study aimed to use external sleep disturbance as a model to evaluate sleep architecture in climacteric women before and after menopausal hormone therapy (MHT). METHODS: Seventeen perimenopausal and 18 postmenopausal women underwent a polysomnography protocol: an adaptation night, a reference night and a sleep disturbance night with one hand loosely tied to the bed for blood sampling. The sleep architecture of the reference and disturbance nights were compared. The 24-h urinary free cortisol concentration (UFC) was measured. The procedure was repeated after 6 months on MHT or placebo. RESULTS: Fifteen perimenopausal and 17 postmenopausal women completed the study. The perimenopausal and postmenopausal groups were combined. During external sleep disturbance, sleep was shorter and more fragmented; with less stage 2, slow-wave and rapid eye movement (REM) sleep and more wake time and awakenings, both at baseline and after the treatment period. Compared to the placebo group, sleep disturbance was minor for women on MHT: sleep was not shortened and the amount of slow-wave sleep did not decrease. Increased 24-h UFC was observed only during MHT. CONCLUSIONS: Sleep in climacteric women is easily disturbed, leading to shorter and more fragmented sleep with less deep sleep and REM sleep. Six months of MHT attenuates the observed sleep disturbance.

Multiple sclerosis and vitamin D during pregnancy and lactation.

BACKGROUND: Both pregnancy and high vitamin D concentration seem to generate a protective environment against multiple sclerosis (MS) relapses. Longitudinal case-control analysis of vitamin D concentrations during pregnancy and lactation of MS mothers is lacking. AIMS OF THE STUDY: To examine serum 25-hydroxyvitamin-D3 levels of MS patients during and after pregnancy and compare these to the levels measured in healthy controls. METHODS: Fifteen relapsing-remitting MS mothers underwent repeated testing for 25-hydroxyvitamin-D3 at 10-12, 26-28 and 35-37 gestational weeks and 1, 3 and 6 months post-partum. An identical series of samples was collected from six control mothers. RESULTS: The prevalence of vitamin D deficiency (<50 nmol/l) during pregnancy was high (73%) among MS patients. Vitamin D levels were significantly higher during pregnancy when compared to early post-partum values among MS patients. At the end of the follow-up period, the vitamin D levels returned to levels observed in early pregnancy. In healthy controls, the alterations during and after pregnancy were similar in nature, but the vitamin D concentrations were higher at all time points when compared to MS patients (P = 0.037). CONCLUSIONS: Vitamin D deficiency during the pregnancy and lactation seems to be common in mothers with MS and needs to be treated adequately.

Effects of fluoxetine treatment on striatal dopamine transporter binding and cerebrospinal fluid insulin-like growth factor-1 in children with autism.

A positive effect of fluoxetine has been shown in some children with autism. The present study was undertaken to correlate striatal dopamine transporter (DAT) binding and cerebrospinal fluid insulin-like growth factor-1 (CSF-IGF-1) with clinical response in autistic children (n=13, age 5-16 years) after a 6-month fluoxetine treatment. Good clinical responders (n=6) had a decrease (p=0.031) in DAT binding as assessed using single-photon emission computed tomography with [123I]-nor-ß-CIT, whereas poor responders had a trend to an increase. An increase in CSF-IGF-1 (p=0.003) was detected after the treatment period, but no correlation between the clinical response and CSF-IGF-1 was found. In conclusion, fluoxetine decreases DAT binding indicating alleviation of the hyperdopaminergic state and increases CSF-IGF-1 concentration, which may also have a neuroprotective effect against dopamine-induced neurotoxicity in autistic children.

Decreased oxygen saturation as a result of haemoglobin Titusville.

INTRODUCTION: Our patient was admitted to the hospital due to shortness of breath. Although partial pressure of oxygen in arterial blood was normal, oxygen saturation measured with pulse oximetry (SpO(2)) was markedly decreased. SpO(2) and oxygen saturation of arterial blood (SaO(2)) stayed low during monitoring even with an increased fraction of oxygen in inspired air. METHODS: Report of a case. RESULTS: After extensive investigations, a rare haemoglobin variant, haemoglobin Titusville, with decreased oxygen binding capacity was discovered. This is the first haemoglobin Titusville case reported in Scandinavian countries.

Determination of testosterone in serum by liquid chromatography-tandem mass spectrometry.

Commercial direct immunoassays for serum testosterone sometimes result in inaccuracies in samples from women and children, leading to misdiagnosis and inappropriate treatment. The diagnosis of male hypogonadism also requires an accurate testosterone assay method. We therefore developed a sensitive and specific stable-isotope dilution liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for serum testosterone at the concentrations encountered in women and children. Testosterone was extracted with ether-ethyl acetate from 250 microL or 500 microL of serum. Instrumental analysis was performed on an API 2000 tandem mass spectrometer in the multiple-reaction monitoring (MRM) mode after separation on a reversed-phase column. The MRM transitions (m/z) were 289/97 for testosterone and 291/99 for d(2) testosterone. The calibration curves exhibited consistent linearity and repeatability in the range 0.2-100 nmol/L. Interassay CVs were 4.2-7.6 % at mean concentrations of testosterone of 3.3-45 nmol/L. Total measurement uncertainty (U, k = 2) was 12.9 % and 13.4 % at testosterone levels of 2.0 nmol/L and 20 nmol/L, respectively. The limit of detection was 0.05 nmol/L (signal-to-noise ratio = 3) and the overall method recovery of testosterone was 95 %. Correlation (r) with our in-house extraction RIA was 0.98 and with a commercial RIA 0.92. Reference intervals for adult males and females in age groups 18-30, 31-50, 51-70 and over 70 years were established. Sensitivity and specificity of the LC-MS/MS method offer advantages over immunoassay and make it suitable for use as a high-throughput assay in routine clinical laboratories. The high equipment costs are balanced by higher throughput together with shorter chromatographic run times.

Determination of free tetrahydrocortisol and tetrahydrocortisone ratio in urine by liquid chromatography-tandem mass spectrometry.

OBJECTIVE: Measurement of urinary free tetrahydrocortisol and tetrahydrocortisone ratio (allo-THF+THF)/THE is clinically important in the diagnosis of hypertension caused by congenital absence of 11beta-hydroxysteroid dehydrogenase type 2 (apparent mineralocorticoid excess, AME) or inhibition of the enzyme after licorice ingestion. Although gas chromatography-mass spectrometry (GC-MS) provides reliable results, it requires derivatization and is lengthy and time-consuming. The purpose of this study was to demonstrate that detection by liquid chromatography-mass spectrometry (LC-MS) is a potentially superior method. MATERIAL AND METHODS: The analysis utilizes 1 mL urine. The samples were extracted with solid-phase extraction (SPE) using ethyl acetate as eluent. The extract was evaporated to dryness, and allo-tetrahydrocortisol (allo-THF), THF and THE concentrations were analyzed by LC-MS/MS operating in the negative mode after separation on a reversed-phase column. The calibration curves exhibited consistent linearity and reproducibility in the range of 7.5-120 nmol/L. Interassay CVs were 7.0-10 % at mean ratios of (allo-THF+THF)/THE of 0.54-1.9. The detection limit of the analytes was 0.4-0.8 nmol/L (signal-to-noise ratio = 3). The mean recovery of the three analytes ranged from 88 to 95 %. The regression equation for the free ratio using the LC-MS/MS (x) method and the total ratio using the GC-MS (y) method was: y = 0.30x+0.91 (r = 0.61; n = 25). CONCLUSIONS: The sensitivity and specificity of the LC-MS/MS method offer an advantage over GC-MS by eliminating derivatization. The high costs of equipment are balanced by higher through-put, owing also to shorter chromatographic run times.

Potentially hallucinogenic 5-hydroxytryptamine receptor ligands bufotenine and dimethyltryptamine in blood and tissues.

Bufotenine and N,N-dimethyltryptamine (DMT) are hallucinogenic dimethylated indolethylamines (DMIAs) formed from serotonin and tryptamine by the enzyme indolethylamine N-methyltransferase (INMT) ubiquitously present in non-neural tissues. In mammals, endogenous bufotenine and DMT have been identified only in human urine. The DMIAs bind effectively to 5HT receptors and their administration causes a variety of autonomic effects, which may reflect their actual physiological function. Endogenous levels of bufotenine and DMT in blood and a number of animal and human tissues were determined using highly sensitive and specific quantitative mass spectrometric techniques. A new finding was the detection of large amounts of bufotenine in stools, which may be an indication of its role in intestinal function. It is suggested that fecal and urinary bufotenine originate from epithelial cells of the intestine and the kidney, respectively, although the possibility of their synthesis by intestinal bacteria cannot be excluded. Only small amounts of the DMIAs were found in somatic or neural tissues and none in blood. This can be explained by rapid catabolism of the DMIAs by mitochondrial monoamino-oxidase or by the fact that the dimethylated products of serotonin and tryptamine are not formed in significant amounts in most mammalian tissues despite the widespread presence of INMT in tissues.

Determination of 17alpha-hydroxyprogesterone in serum by liquid chromatography-tandem mass spectrometry and immunoassay.

17Alpha-hydroxyprogesterone (17OHP) is the most important serum marker for congenital adrenal hyperplasia (CAH). 17OHP is usually measured by immunoassay but its detection by mass spectrometry (MS) is a potentially superior method. An LC-MS (liquid chromatography-mass spectrometry) method was developed which utilizes 0.5 ml serum spiked with 6-alpha-methylprednisolone (6-MP) or deuterated 17OHP (d8-IS) as the internal standard. The samples were extracted with ether/ethylacetate, and the extract was evaporated to dryness and analysed by LC-MS/MS operating in the positive mode after separation on a reversed-phase C18 column. The calibration curves for analysis of serum 17OHP exhibited consistent linearity and reproducibility in the range of 5-250 nmol/l. Interassay CVs were 8.5 and 9.2% at mean concentrations of 7.9 and 23 nmol/l, respectively. The detection limit was 1 nmol/l (signal-to-noise ratio=3). The mean recovery of 17OHP added to serum ranged from 76 to 89% and that of internal standards from 75 to 82%. The regression equation for the LC-MS/MS (x) and in-house radioimmunoassay (RIA) (y) methods was: y=0.87x+0.26 (r=0.97; n=100) and for a commercial RIA it was: y=1.32x+0.02 (r=0.97; n=26).

Cerebrospinal fluid insulin-like growth factor (IGF-1) and insulin-like growth factor binding protein (IGFBP-2) in children with acute lymphoblastic leukemia.

BACKGROUND: Insulin-like growth factor-1 (IGF-1) has specific effects on axonal growth and myelination, low CSF IGF-1 levels being found in some severe neurologic diseases. We studied the levels of CSF IGF-1 and IGF binding protein-2 (IGFBP-2) in children with ALL to find out whether these levels correlated with any of the neurological deficits observed. METHODS: IGF-1 and IGFBP-2 levels were prospectively measured by radioimmunoassay in the CSF of 14 children with ALL throughout the ALL chemotherapy. These were compared with the levels of 16 control subjects and of patient groups with severe neurological diseases. RESULTS: During induction, the children with ALL had subnormal CSF IGF-1 levels which improved after 2 months. In seven individuals, two with severe vincristine polyneuropathy, the subnormal levels persisted throughout the chemotherapy. CONCLUSIONS: Our findings suggest impairment of the IGF-1 trophic system during induction by a mechanism so far unknown. Correlation with disturbed neuronal function could not be statistically proven.

Cerebrospinal fluid insulin-like growth factor-1, insulin growth factor binding protein-2 or nitric oxide are not increased in MS or ALS.

OBJECTIVES: Many studies have shown that nitric oxide (NO) and growth factors including insulin growth factors (IGFs) may be involved in the pathogenesis of multiple sclerosis (MS) and neurodegenerative diseases. Our previous studies suggested a relationship between cerebrospinal fluid (CSF) NO metabolites (nitrates and nitrites, NN(x)) and IGF-1 in patients with progressive encephalopathy, hypsarrhythmia and optic atrophy syndrome. MATERIAL AND METHODS: We examined CSF concentrations of NN(x), IGF-1 and IGF binding protein-2 (IGFBP-2) in 25 controls, 14 patients with MS and 14 patients with amyotrophic lateralis sclerosis (ALS). RESULTS: There were no significant differences in CSF levels of NN(x), IGF-1 or IGFBP-2 between the groups. CSF IGFBP-2 concentrations correlated significantly with age in controls, which may reflect age-related changes in the blood-brain barrier function. CONCLUSION: Upregulation of the production of NO and IGF-1 in the brain or spinal cord does not influence CSF levels of these molecules in MS or ALS.

Determination of urinary free cortisol by liquid chromatography-tandem mass spectrometry.

Measurement of urinary free cortisol is clinically important in the diagnosis of Cushing's syndrome. While liquid chromatography (LC) with UV detection provides much better specificity than immunologic methods, certain drugs cause interference. Detection by mass spectrometry (MS) is a potentially superior method. Our analysis utilizes 1 mL urine spiked with 6-alpha-methylprednisolone as internal standard. The samples were extracted with dichlormethane and the extract was washed, evaporated to dryness and analyzed by LC-MS/MS operating in the negative mode after separation on a reversed-phase C18 column. The calibration curves for analysis of urinary cortisol exhibited consistent linearity and reproducibility in the range of 10-400 nmol/L. Inter-assay CVs were 4.0-7.6%, at mean concentrations of 21-153 nmol/L. The detection limit was 1 nmol/L (signal-to-noise ratio=3). The mean recovery of cortisol added to urine ranged from 67% to 87% and that of the internal standard from 71% to 76%. The regression equation for the LC-MS/MS (x) and HPLC (y) methods was: y=1.095x+8.0 (r=0.996; n=111). Drugs known to interfere with UV detection did not cause problems here. The sensitivity and specificity of the MS/MS method for urinary free cortisol offer advantages over HPLC with UV detection by eliminating drug interference. The higher equipment costs in comparison with HPLC methods using UV detection are balanced by higher throughput, thanks to shorter chromatographic run times.

Comparison of HPLC and small column (CDTect) methods for disialotransferrin.

BACKGROUND: Current methods for determination of carbohydrate-deficient transferrin (CDT) are based on separation of the CDT fraction by ion-exchange chromatography on minicolumns and quantification by immunoassay. Alternatively, the transferrin isoforms can be separated by HPLC anion-exchange chromatography and quantified by absorbance. This method has been reported to improve the validity of CDT as a marker of chronic alcohol abuse. METHODS: HPLC on either MonoQ or ResourceQ anion-exchange columns was used to separate and quantify isoforms of transferrin with detection at 460 nm. The result was expressed as the percentage of the disialo form (pI 5.7) of total transferrin (DST). The commercial CDTect assay was used as a comparison method. Serum samples from nondrinkers (n = 57), moderate drinkers (n = 77), and heavy drinkers (n = 139) were analyzed. RESULTS: In ROC analysis for differentiation between moderate and heavy drinkers, the area under the curve (AUC) for the HPLC method was 0.87 (95% confidence interval, 0.81-0.93), whereas that for CDTect was 0.72 (95% confidence interval, 0.64-0.80). At 90% specificity, the sensitivity of DST was 63% (95% confidence interval, 53-73%) compared with 33% (22-44%) for CDT. The reference interval of the HPLC method was 0.68-1.7%. CONCLUSIONS: The HPLC anion-exchange method for quantification of CDT provides substantially better separation between moderate and heavy drinkers than the CDTect method.

Low levels of insulin-like growth factor-I in cerebrospinal fluid in children with autism.

Autism is a behaviourally defined syndrome characterized by disturbances of social interaction and communication and restrictions of behaviour patterns and imagination. The pathogenesis of autism is unknown but it is suspected that a number of genetic factors may be involved. Neurotrophic factors such as insulin-like growth factor-I (IGF-I) play a role in early brain development. The aim of this study was to determine whether IGF-I levels might be associated with the development of autism. IGF-I levels were measured in the CSF of 11 children with autism (4 females, 7 males; mean age 3.8 years, SD 1.1) using a sensitive radioimmunoassay method and compared with levels in 11 control participants (6 females, 5 males; mean age 3.8 years). Levels of IGF-I in the CSF were statistically significantly lower in the children with autism than in the control children (p=0.03). IGF-I may play a role in pathogenetic mechanisms of autism and the role of neurotrophic factors in autism and other neurodevelopmental diseases should be studied further.

Evolution of cerebral tumor necrosis factor-alpha production during human ischemic stroke.

BACKGROUND AND PURPOSE: Tumor necrosis factor-alpha (TNF-alpha) is detected in ischemic brain cells in experimental animal models and is believed to play an important role in apoptosis. However, the natural expression of TNF-alpha during human stroke is not known. METHODS: We examined TNF-alpha immunohistochemistry and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) in brain samples of stroke victims (n=16) after variable survival (15 hours to 18 days). Systemic TNF-alpha content from a separate cohort including severe or lethal stroke cases (n=26) was also assayed. RESULTS: Neuronal TNF-alpha was demonstrated from 0.6 to 5.4 days after the onset of stroke symptoms, peaking bilaterally during days 2 and 3. Bilateral glial TNF-alpha immunoreactivity was detected during the acute phase, with the astrocytic TNF-alpha expression dominating in later phases and persisting contralaterally to the infarct in more matured phases (17 to 18 days). Invading inflammatory cells were TNF-alpha immunopositive beginning on the third day. Besides, vascular wall structures showed immunoreactivity sporadically. TNF-alpha levels were mostly nondetectable in peripheral blood. TUNEL labeling and TNF-alpha staining overlapped, although not completely, during the first days. CONCLUSIONS: The data support the hypothesis that TNF-alpha may be involved both in the acute propagation of inflammatory processes and cell death and possibly in the more delayed reconstitutive processes of human ischemic stroke.

Serum homocysteine at 16 weeks and subsequent preeclampsia.

OBJECTIVE: To determine whether elevated homocysteine levels precede the development of preeclampsia. METHODS: Study subjects were selected from a population-based cohort of 1049 nulliparous women from whom serum was collected for Down syndrome screening at 16 weeks' gestation. For 34 women who developed preeclampsia, 68 control women were chosen who remained normotensive. Homocysteine was analyzed by high-performance liquid chromatography and fluorescence detection. The sample size allowed detection of a 1.25-micromol/L difference at a significance level of 0.05 and the power of 0.81. RESULTS: At 16 weeks' gestation, concentrations (mean, 95% confidence interval) of homocysteine in women who developed preeclampsia, 6.99 (6.42, 7.55) micromol/L, were similar to those who remained normotensive, 6.91 (6.45, 7.34) micromol/L. CONCLUSION: Significant changes in homocysteine metabolism did not predate the appearance of clinical preeclampsia.

Failure of the combination of sequential oral and transdermal estradiol plus norethisterone acetate to affect plasma homocysteine levels.

OBJECTIVE: A high level of plasma homocysteine may be deleterious to vascular health. We therefore compared the effect of combinations of sequential oral and transdermal estradiol plus norethisterone acetate on plasma homocysteine. DESIGN: Prospective, randomized study. SETTING: Outpatient department of obstetrics and gynecology in a university hospital. PATIENT(S): Forty-two healthy, nonsmoking postmenopausal women starting hormone replacement therapy (HRT) to control climacteric symptoms. INTERVENTION(S): In a randomized order, the women started using either oral HRT (2 mg of estradiol on days 1-12, 2 mg of estradiol plus 1 mg of norethisterone acetate (NETA) on days 13-22, and 1mg of estradiol on days 23-28; n = 21) or transdermal HRT (50 microg/d of estradiol on days 1-28 and 250 microg/d of norethisterone acetate on days 15-28, n = 21) for 1 year. MAIN OUTCOME MEASURE(S): Fasting plasma levels of homocysteine were measured before the treatment and during the combined estradiol-plus-NETA phases of the sixth and 12th treatment cycles. RESULT(S): Basal homocysteine levels in the oral group (8.2 +/- 3.1 micromol/L, mean plusmn;SD) and transdermal group (8.7 plusmn; 1.8 micromol/L, mean plusmn;SD) were not affected by the estradiol-plus-NETA combination. CONCLUSION(S): Neither an oral nor a transdermal combination of sequential estradiol and NETA causes significant changes in plasma homocysteine in Finnish postmenopausal women with normal baseline homocysteine levels.

Bright light exposure of a large skin area does not affect melatonin or bilirubin levels in humans.

BACKGROUND: Light treatment through the eyes is effective in alleviating the symptoms of some psychiatric disorders. A recent report suggested that skin light exposure can affect human circadian rhythms. Bilirubin can serve as a hypothetical blood-borne mediator of skin illumination into the brain. We studied whether bright light directed to a large body area could suppress the pineal melatonin secretion or decrease serum total bilirubin in conditions that could be used for therapeutic purposes. METHODS: Seven healthy volunteers participated in two consecutive overnight sessions that were identical except for a light exposure on the chest and abdomen in the second night from 12:00 AM to 6:00 AM (10,000-lux, 32 W/m(2) cool white for six subjects and 3000-lux, 15 W/m(2) blue light for one subject). Hourly blood samples were collected from 7:00 PM to 7:00 AM for melatonin radioimmunoassays. Bilirubin was measured by a modified diazo method in blood samples taken at 12:00 AM and 6:00 AM and in urine samples collected from 7:00 PM to 11:00 PM and from 11:00 PM to 7:00 AM. RESULTS: The skin light exposure did not cause any significant changes in serum melatonin or bilirubin levels. The excretion of bilirubin in urine was also the same in both sessions. CONCLUSIONS: Significant melatonin suppression by extraocular light does not occur in humans. Robust concentration changes of serum total bilirubin do not have a role in mediating light information from the skin to the central nervous system.

CSF insulin-like growth factor-1 in infantile neuronal ceroid lipofuscinosis.

BACKGROUND: Infantile neuronal ceroid lipofuscinosis (INCL) is a progressive encephalopathy in which the patients are severely disabled by the age of 3 years. It is characterized by cerebral atrophy, selective loss of cortical neurons, and secondary loss of axons and myelin sheaths of the white matter. INCL has been shown to result from a palmitoyl protein thioesterase deficiency. The authors suggested that insulin-like growth hormones and apoptosis might play a role in the pathogenesis of INCL. METHODS: The authors measured insulin-like growth factor-1 (IGF-1) and IGF binding protein 3 (IGFBP-3) in the CSF of patients with INCL by radioimmunoassay at an early stage when myelin was starting to diminish. RESULTS: The authors found low CSF IGF-1 but normal IGFBP-3 in patients with INCL compared with control subjects. Also, they observed apoptotic cell death in biopsies of INCL patients. CONCLUSIONS: Because the IGF system seems to be important for early brain development, myelination, and neuroprotection, the authors suggest that the pathology in INCL may be associated with low CSF IGF-1.

Insulin-like growth factor-I in cerebrospinal fluid and serum in Rett syndrome.

Rett syndrome is a neurodevelopmental disease characterized by failure of somatic and brain growth. The insulin-like growth factor system mediates most actions of growth hormone. Evidence that it plays an important role in early development of the brain is increasing. The aim of the study reported was to assess the role of the insulin-like growth factor system in the pathogenesis of Rett syndrome. We measured insulin-like growth factor-I levels in serum (8 patients, mean age 9.1 years) and cerebrospinal fluid (13 patients, mean age 7 years) using a sensitive radioimmunoassay method and compared them with those in age-matched controls (13 and 26 patients, respectively). Neither serum nor cerebrospinal fluid insulin-like growth factor-I levels differed from those in controls. We also measured insulin-like growth factor binding protein-3 levels in serum (in 9 patients and 8 controls) and in cerebrospinal fluid (in 12 patients and 11 controls) and serum growth hormone levels (in 8 patients and 11 controls); the levels in patients did not differ from those in controls. We found no significant correlation between serum and cerebrospinal fluid insulin-like growth factor-I in Rett syndrome. This may indicate an independent role of insulin-like growth factor system in the central nervous system, making serum insulin-like growth factor-I measurement unreliable as an indicator of disturbed function in the central nervous system. Our results did not support the notion that a defective insulin-like growth factor-I system explains the lack of somatic and brain growth in Rett syndrome.

Comparison of iohexol and lactulose-mannitol tests as markers of disease activity in patients with inflammatory bowel disease.

Increased intestinal permeability has been proposed as one aetiological factor for inflammatory bowel diseases (IBD). We have previously found that intestinal permeability of a water-soluble contrast medium, iohexol, correlates with disease activity. The objective was to compare the iohexol test with the lactulose-mannitol ratio, which is a more extensively studied permeability marker, in patients with active IBD. Urinary excretion of iohexol was compared to the lactulose-mannitol ratio in 22 patients with an exacerbation of IBD and in 10 healthy controls. Median intestinal absorption of iohexol was 0.64% (range 0.13-3.8%) in the 22 patients and 0.3% (range 0.15-0.54%) in the controls (p = 0.016), whereas the median lactulose-mannitol ratio was 0.037 (range 0.01-0.260) in patients and 0.03 (range 0.004-0.063) in controls (N.S.). Correlation between urinary excretion of iohexol and lactulose-mannitol ratio was positive (R = +0.41, p = 0.018). The urinary excretion of iohexol correlated positively with endoscopic disease activity (R = +0.74, p < 0.001) and the modified Harvey-Bradshaw index (R = +0.44, p = 0.04). The lactulose-mannitol ratio correlated positively with endoscopic disease activity (R = +0.44, p = 0.05), but correlations with clinical index or c-reactive protein were poor. In conclusion, the iohexol test is a superior activity marker compared to the lactulose-mannitol ratio which probably reflects, instead, some pathogenic property of IBD.