Validations of calibration-free measurements of electron temperature using double-pass Thomson scattering diagnostics from theoretical and experimental aspects.

This paper evaluates the accuracy of electron temperature measurements and relative transmissivities of double-pass Thomson scattering diagnostics. The electron temperature (Te) is obtained from the ratio of signals from a double-pass scattering system, then relative transmissivities are calculated from the measured Te and intensity of the signals. How accurate the values are depends on the electron temperature (Te) and scattering angle (θ), and therefore the accuracy of the values was evaluated experimentally using the Large Helical Device (LHD) and the Tokyo spherical tokamak-2 (TST-2). Analyzing the data from the TST-2 indicates that a high Te and a large scattering angle (θ) yield accurate values. Indeed, the errors for scattering angle θ = 135° are approximately half of those for θ = 115°. The method of determining the Te in a wide Te range spanning over two orders of magnitude (0.01-1.5 keV) was validated using the experimental results of the LHD and TST-2. A simple method to provide relative transmissivities, which include inputs from collection optics, vacuum window, optical fibers, and polychromators, is also presented. The relative errors were less than approximately 10%. Numerical simulations also indicate that the Te measurements are valid under harsh radiation conditions. This method to obtain Te can be considered for the design of Thomson scattering systems where there is high-performance plasma that generates harsh radiation environments.

A model of plasma current through a hole of Rogowski probe including sheath effects.

In TST-2 Ohmic discharges, local current is measured using a Rogowski probe by changing the angle between the local magnetic field and the direction of the hole of the Rogowski probe. The angular dependence shows a peak when the direction of the hole is almost parallel to the local magnetic field. The obtained width of the peak was broader than that of the theoretical curve expected from the probe geometry. In order to explain this disagreement, we consider the effect of sheath in the vicinity of the Rogowski probe. A sheath model was constructed and electron orbits were numerically calculated. From the calculation, it was found that the electron orbit is affected by E × B drift due to the sheath electric field. Such orbit causes the broadening of the peak in the angular dependence and the dependence agrees with the experimental results. The dependence of the broadening on various plasma parameters was studied numerically and explained qualitatively by a simplified analytical model.

Positive association of free triiodothyronine with pancreatic ß-cell function in people with prediabetes.

AIM: To analyse the effects of thyroid hormones on ß-cell function and glucose metabolism in people with prediabetes who are euthyroid. METHODS: A total of 111 people who were euthyroid underwent 75-g oral glucose tolerance tests, of whom 52 were assigned to the normal glucose tolerance and 59 to the prediabetes groups. Homeostatic model assessment of ß-cell function, insulinogenic index and areas under the curve for insulin and glucose were evaluated as indices of pancreatic ß-cell function. RESULTS: In both groups, BMI, fasting insulin, homeostasis model assessment ratio and HDL cholesterol correlated significantly with all indices of pancreatic ß-cell function. Free triiodothyronine correlated positively with all insulin secretion indices in the prediabetes group. Multiple linear regression analysis showed that free triiodothyronine was an independent variable that had a positive correlation with all indices of ß-cell function in the prediabetes group. By contrast, no such correlation was found in the normal glucose tolerance group. CONCLUSIONS: Free triiodothyronine is associated with both basal and glucose-stimulated insulin secretion in people with prediabetes who are euthyroid; therefore, the regulation of insulin secretion by thyroid hormones is a potentially novel therapeutic target for the treatment of diabetes.

Local current density measurement using a Rogowski probe in Tokyo Spherical Tokamak-2.

A Rogowski probe consisting of a small multi-layer Rogowski coil, five magnetic pick-up coils, and a Langmuir probe was developed to measure the local current density and its direction. It can be moved along the major radius and can be turned around its axis. This probe was used to measure the current density profile near the last closed flux surface of Ohmic plasmas in Tokyo Spherical Tokamak-2. The current density profile was measured successfully with a signal to noise ratio of greater than 20.

Demonstration of improvement in the signal-to-noise ratio of Thomson scattering signal obtained by using a multi-pass optical cavity on the Tokyo Spherical Tokamak-2.

The multi-pass Thomson scattering (TS) scheme enables obtaining many photons by accumulating multiple TS signals. The signal-to-noise ratio (SNR) depends on the accumulation number. In this study, we performed multi-pass TS measurements for ohmically heated plasmas, and the relationship between SNR and the accumulation number was investigated. As a result, improvement of SNR in this experiment indicated similar tendency to that calculated for the background noise dominant situation.

Note: Multi-pass Thomson scattering measurement on the TST-2 spherical tokamak.

In multi-pass Thomson scattering (TS) scheme, a laser pulse makes multiple round trips through the plasma, and the effective laser energy is enhanced, and we can increase the signal-to-noise ratio as a result. We have developed a coaxial optical cavity in which a laser pulse is confined, and we performed TS measurements using the coaxial cavity in tokamak plasmas for the first time. In the optical cavity, the laser energy attenuation was approximately 30% in each round trip, and we achieved a photon number gain of about 3 compared with that obtained in the first round trip. In addition, the temperature measurement accuracy was improved by accumulating the first three round trip waveforms.

Mechanisms underlying ketamine-induced synaptic depression in rat hippocampus-medial prefrontal cortex pathway.

The non-competitive N-methyl-D-aspartate NMDA receptor antagonist ketamine, a dissociative anesthetic capable of inducing analgesia, is known to have psychotomimetic actions, but the detailed mechanisms remain unclear because of its complex properties. The present study elucidated neural mechanisms of the effect of ketamine, at doses that exert psychotomimetic effects without anesthetic and analgesic effects, by evaluating cortical synaptic responses in vivo. Systemic administration (i.p.) of low (1 and 5 mg/kg), subanesthetic (25 mg/kg) and anesthetic (100 mg/kg) doses of ketamine dose-dependently decreased hippocampal stimulation-evoked potential in the medial prefrontal cortex (mPFC) in freely moving rats. The behavioral analysis assessed by prepulse inhibition (PPI) of acoustic startle response showed that ketamine (5 and 25 mg/kg, i.p.) produced PPI deficit. Thus, the psychotomimetic effects observed in ketamine-treated groups (5 and 25 mg/kg, i.p.) are associated with the induction of synaptic depression in the hippocampus-mPFC neural pathway. Based on these results, we further examined the underlying mechanisms of the ketamine-induced synaptic depression under anesthesia. Ketamine (5 and 25 mg/kg, i.p.) caused increases in dialysate dopamine in the mPFC in anesthetized rats. Moreover, the ketamine-induced decreases in the evoked potential, at the dose 5 mg/kg which has no anesthetic and analgesic effects, were indeed absent in dopamine-lesioned rats pretreated with 6-hydroxydopamine (6-OHDA; 150 µg/rat, i.c.v.). Ketamine (5 mg/kg, i.p.)-induced synaptic depression was blocked by pretreatment with dopamine D1 receptor antagonist SCH 23390 (10 µg/rat, i.c.v.) but not dopamine D2 receptor antagonist haloperidol (1.5 mg/kg, i.p.), suggesting that dopaminergic modulation mediated via D1 receptors are involved in the synaptic effects of ketamine. Furthermore, ketamine (5 mg/kg, i.p.)-induced synaptic depression was prevented also by GABAA receptor antagonist bicuculline (0.2 or 2 µg/rat, i.c.v.). These findings suggest that ketamine at the dose that exerts psychotomimetic symptoms depresses hippocampus-mPFC synaptic transmission through mechanisms involving dopaminergic modulation mediated via D1 receptors, which may lead to a net augmentation of synaptic inhibition mediated via GABAA receptors.

Early stress exposure impairs synaptic potentiation in the rat medial prefrontal cortex underlying contextual fear extinction.

Traumatic events during early life may affect the neural systems associated with memory function, including extinction, and lead to altered sensitivity to stress later in life. We recently reported that changes in prefrontal synaptic efficacy in response to extinction trials did not occur in adult rats exposed to early postnatal stress (i.e. footshock [FS] stress during postnatal day 21-25 [3W-FS group]). However, identifying neurocircuitry and neural mechanisms responsible for extinction retrieval after extinction training have not been precisely determined. The present study explored whether synaptic transmission in the hippocampal-medial prefrontal cortex (mPFC) neural pathway is altered by extinction retrieval on the day after extinction trials using electrophysiological approaches combined with behavioral analysis. We also elucidated the effects of early postnatal stress on the synaptic response in this neural circuit underlying extinction retrieval. Evoked potential in the mPFC was enhanced following extinction retrieval, accompanied by reduced freezing behavior. This synaptic facilitation (i.e. a long-term potentiation [LTP]-like response) did not occur; rather synaptic inhibition was observed in the 3W-FS group, accompanied by sustained freezing. The behavioral deficit and synaptic inhibition observed in the 3W-FS group were time-dependently ameliorated by the partial N-methyl-D-aspartate (NMDA) receptor agonist D-cycloserine (15 mg/kg, i.p.). These findings suggest that the LTP-like response in the hippocampal-mPFC pathway is associated with extinction retrieval of context-dependent fear memory. Early postnatal stress appears to induce neurodevelopmental dysfunction of this neural circuit and lead to impaired fear extinction later in life. The present data indicate that psychotherapy accompanied by pharmacological interventions that accelerate and strengthen extinction, such as d-cycloserine treatment, may have therapeutic potential for the treatment of anxiety disorders, including posttraumatic stress disorder.

Effects of propofol and halothane on long-term potentiation in the rat hippocampus after transient cerebral ischaemia.

BACKGROUND: Propofol is reported to have protective effects on cerebral ischaemia-induced neuronal death. The aim of this study was to explore whether propofol and halothane can protect hippocampal neuronal function from ischaemic injury during general anaesthesia in rats. METHODS: Rats were divided into 2-vessel occlusion (incomplete cerebral ischaemia) and 4-vessel occlusion (complete cerebral ischaemia) groups consisting of three subgroups each (sham-operated, propofol and halothane groups). One hour after starting propofol 1 mg kg(-1) min(-1) with 30% O2 and N2 or halothane 0.8% in 30% O2 and N2 rats with or without bilateral vertebral artery occlusion had bilateral common carotid arteries occluded by vessel clips for 10 min. Anaesthesia was maintained for another 1 h. Seven days after ischaemia-reperfusion, hippocampal long-term potentiation in the perforant path-dentate gyrus synapse was determined as an index of cerebral outcome. RESULTS: In the propofol groups, the formation of long-term potentiation was significantly impaired in the 2-vessel and 4-vessel occlusion groups compared to the respective sham-operated groups (P < 0.01 and P < 0.05, respectively). Impaired formation of long-term potentiation in propofol groups was comparable to that in halothane groups. The formation of long-team potentiation in the propofol and halothane 2-vessel group was not significantly different from that in the awake 2-vessel group. CONCLUSIONS: Propofol and halothane administered during ischaemia do not possess protective effects against hippocampal neuronal dysfunction induced by cerebral ischaemia-reperfusion as evaluated by our transient ischaemic rat models.

Fluctuation of fecal microbiota in individuals with Japanese cedar pollinosis during the pollen season and influence of probiotic intake.

BACKGROUND: We have previously reported the results of a randomized, double-blind, placebo-controlled trial that found the intake of yogurt supplemented with a probiotic strain, Bifidobacterium longum BB536, alleviates symptoms and affects blood parameters in individuals with Japanese cedar pollinosis (JCPsis) during the pollen season. OBJECTIVE: In the present study, fecal microbiota were investigated to examine whether any changes occur during the pollen season and whether any influence is exerted by probiotic intake. METHODS: Yogurt either with BB536 (BB536 yogurt) or without BB536 (placebo yogurt) was administered for 14 weeks at 2 x 100 g per day to 40 subjects (17 men, 23 women) with a clinical history of JCPsis. Fecal samples were obtained from 23 subjects (placebo group, n=13; BB536 group, n=10) before and during the intervention (weeks 4, 9 and 13) and fecal microbiota were analyzed using terminal-restriction fragment length polymorphism and real-time polymerase chain reaction (PCR) methods. RESULTS: From the fluctuation patterns of terminal-restriction fragments, the Bacteroides fragilis group and bifidobacteria were among the species that changed most with pollen dispersion. Real-time PCR analyses indicated that the cell numbers of the B fragilis group increased significantly along with pollen dispersion in both BB536 and placebo groups. Cell numbers of bifidobacteria were significantly higher in the BB536 group compared with the placebo group (P < .05 at weeks 4 and 9). The ratio of cell numbers of the B fragilis group to bifidobacteria increased significantly during the pollen season in the placebo group (P < .01 at weeks 9 and 14), but not in the BB536 group. An in vitro study using peripheral blood mononuclear cells from JCPsis subjects indicated that strains of the B fragilis group induced significantly more helper T cell (T(H)) type2 cytokines (interleukin [IL]-6) but fewer T(H)1 cytokines (IL-12 and interferon) compared with those of bifidobacteria. CONCLUSIONS: These results suggest a relationship between fluctuation in intestinal microbiota and pollinosis allergy. Furthermore, intake of BB536 yogurt appears to exert positive ihfluences on the formation of anti-allergic microbiota.

Probiotics in the treatment of Japanese cedar pollinosis: a double-blind placebo-controlled trial.

BACKGROUND: Probiotic bacteria may be effective in the treatment of allergic inflammation and food allergy, but efficacy and underlying mechanisms remain unclear. OBJECTIVE: The present study investigated the effects of probiotic strain Bifidobacterium longum BB536 in the treatment of Japanese cedar pollinosis (JCPsis). METHODS: In a randomized, double-blind, placebo-controlled trial, 44 JCPsis subjects received BB536 or placebo for 13 weeks during the pollen season. Subjective symptoms and self-care measures were recorded daily and blood samples were taken before and during intervention to measure blood levels of parameters related to JCPsis. RESULTS: BB536 intake was associated with a significant reduction in number of subjects prematurely terminated due to severe symptoms and pollinosis medication (P=0.0057 vs. placebo group). Comparison of subjective symptom scores indicated significant decreases in rhinorrhea, nasal blockage and composite scores in the BB536 group compared with the placebo group. Comparison of medical scores showed marked improvements in all symptoms on BB536 intake. A T-helper type 2 (Th2)-skewed immune response occurring along with pollen dispersion was observed. BB536 significantly suppressed increases in plasma thymus- and activation-regulated chemokine and tended to suppress elevations of Japanese cedar pollen (JCP)-specific IgE. CONCLUSION: These results suggest the efficacy of BB536 in relieving JCPsis symptoms, probably through the modulation of Th2-skewed immune response.

Effect of probiotic Bifidobacterium longum BB536 [corrected] in relieving clinical symptoms and modulating plasma cytokine levels of Japanese cedar pollinosis during the pollen season. A randomized double-blind, placebo-controlled trial.

Probiotic microorganisms have been shown to be effective in the treatment of allergic inflammation and food allergy, but their efficacy remains controversial. This study tested the effect of a yogurt supplemented with a probiotic strain Bifidobacterium longum BB536 in the treatment of Japanese cedar pollinosis (JCPsis). Forty subjects with a clinical history of JCPsis were given yoghurt either containing BB536 (BB536 yoghurt) or without BB536 (placebo yoghurt) at 2 X 100 g per day for 14 weeks, in a randomized, double-blind, placebo-controlled trial. Subjective symptoms and self-care measures were recorded daily and blood samples were taken before and during the intervention (at weeks 4, 9, and 14) to measure the blood parameter levels related to JCPsis. Yoghurt supplemented with BB536 significantly alleviated eye symptoms compared with placebo yoghurt (odds ratio 0.31; 95% confidence interval 0.10-0.97; p = 0.044). Although no statistically significant differences were detected, nasal symptoms such as itching, rhinorrhea, and blockage, as well as throat symptoms tended to be relieved with the BB536 yoghurt. BB536 tended to suppress the decreasing blood levels of interferon-gamma (IFN-y) and the increasing blood eosinophil rates; a significantly higher IFN-gamma level was observed for the difference from baseline at week 4. A decreased trend in the difference from baseline levels of JCP-specific IgE levels was also observed at week 4 in the BB536 group compared with the placebo group. In conclusion, these results suggest that intake of BB536-supplemented yoghurt may relieve JCPsis symptoms, probably through a modulating effect on Th balance.

The influence of mycophenolate mofetil versus azathioprine and mycophenolic acid pharmacokinetics on the incidence of acute rejection and infectious complications after renal transplantation.

PURPOSE: The present retrospective study investigated the influence of mycophenolate mofetil (MMF) instead of azathioprine (AZA) as part of tacrolimus-based immunosuppression. Mycophenolic acid (MPA) pharmacokinetic (PK) parameters were used for associations with the incidence of acute rejection (AR) episodes and infectious complications after renal transplantation. METHODS: The 66 consecutive renal transplant recipients reported herein excluded ABO-incompatible transplants or cytomegalovirus (CMV)-seronegative recipients. The immunosuppressive regimen consisted of tacrolimus, steroids, and AZA 1-2 mg/kg/d in 22 patients (between February 1998 and December 2000) or MMF 2 g/d in 44 patients (since January 2001). CMV infection was defined as positive CMV-antigenemia. MPA PK was studied on day 28 after transplantation in 21 recipients. RESULTS: AR occurred in 13.6% of patients in the MMF group compared with 18.2% in the AZA group. The viral infection (CMV, varicella zoster virus, adenovirus hemorrhagic cystitis, and malignancy related to Epstein-Barr [EB] virus) rate was 22.7% in the MMF group and 0% in the AZA group (P = .015). There were no bacterial or fungal infections observed in the 2 groups. MMF dose per body weight was significantly lower among patients with AR than those without AR (25.1 vs 35.6 mg/kg; P = .026). There were no differences in MPA PK parameters between patients with and without viral infections. CONCLUSIONS: Patients treated with MMF required less treatment for AR, however, there were no significant differences. MMF dose per body weight may play an important role in the occurrence of AR. Although virus infections occurred in recipients treated with MMF, MPA PK did not influence the infectious complications after renal transplantation.

Incidence and risk factors of clinical characteristics, tacrolimus pharmacokinetics, and related genomic polymorphisms for posttransplant diabetes mellitus in the early stage of renal transplant recipients.

PURPOSE: Posttransplant diabetes mellitus (PTDM) is an important complication in a tacrolimus (TAC)-based immunosuppressive regimen. The present study investigated the incidence, clinical risk factors, TAC pharmacokinetics (PK), and genomic polymorphisms related to TAC-PK or diabetes mellitus (DM) under the TAC-based immunosuppressive protocol. PATIENTS AND METHODS: Seventy-one nondiabetic renal allograft recipients transplanted from February 1998 to March 2004 were studied. Patients with over 6.5 mg/dL of hemoglobin A1c on sequential blood samples or requiring insulin or oral antidiabetic agents around 6 months after transplantation were diagnosed as having PTDM. RESULTS: Six months after transplantation, 10 recipients (14.1%) developed PTDM. The positive risk factors were age (P = .003) and body mass index (P = .035). There were no significant differences in gender distribution, pretransplant dialysis period, dialysis modality, acute rejection rate, total steroid doses, TAC-PK, or its related genomic polymorphisms between the two groups. In the DM-related polymorphisms, the frequency of PTDM was significant higher in patients with the VDR TaqI tt or Tt genotype than in those with the TT genotype (P = .013). After a multivariate analysis, age over 50 years (P = .007, odds ratio 8.92) and the presence of VDR TaqI t allele (P = .043, odds ratio 6.71) were correlated with the development of PTDM. CONCLUSION: The incidence of PTDM in our series was 14.1%. Age over 50 years was a risk factor. The presence of VDR TaqI t allele might be a risk for PTDM. An association between TAC-PK and development of PTDM was not observed.

Aromatase is abundantly expressed by neonatal rat penis but downregulated in adulthood.

Although synthesis of estrogen by male gonads has been well documented for over half a century, it is only recently that the role of estrogen in male reproductive events has gained appreciation. We recently reported abundant expression of estrogen receptor (ER)-alpha and -beta in different cell types of the rat penis, whose levels diminished with advancing age. The present study, which builds on data from the ER study, was designed to determine whether the penis is capable of generating its own local estrogen by examining evidence of the expression of aromatase, a microsomal enzymatic complex which irreversibly converts androgens to estrogens, using immunohistochemistry, Western blotting, in situ hybridization and real-time PCR analyses. Secondly, the effects of sex steroid hormones on penile aromatase were examined. Discrete aromatase immunoreactive cells were localized in primordial corpus cavernosum, corpus spongiosus and os penis, blood vessels and sensory corpuscle of glans penis. In situ hybridization signals corresponded with immunohistochemical findings. Western blot, enzyme immunoassay and real-time PCR analyses of rat penile samples revealed an age-dependent expression of aromatase and estrogen, with levels at week 1 almost resembling those of the ovary, but they decreased sharply by week 8, and decreased further by week 35. This expression pattern was strikingly similar to that of ER-alpha reported previously. Testosterone and diethylstilbesterol administered prenatally upregulate levels of aromatase mRNA and protein, and estrogen postnatally. Dihydrotestosterone upregulated aromatase mRNA and protein, but not estrogen. We conclude that estrogen acts via ER in a paracrine and/or autocrine manner to regulate penile events, particularly during development, and that estrogen synthesis is regulated by estrogen and androgens.

Effect of tacrolimus and cyclosporine on renal microcirculation and nitric oxide production.

OBJECTIVES: Cyclosporine (CSA) and tacrolimus (TAC) frequently induce nephrotoxicity and similar pathologic changes. Acute CSA-induced nephrotoxicity has been reported to be mediated by activation of vasoconstrictors such as endothelin. The purpose of the present study was to investigate the acute effects of TAC and CSA on the renal microcirculation and upon a vasodilator such as nitric oxide (NO) production. METHODS: Renal blood flow (RBF) in the microcirculation was measured by a Laser Doppler flow meter in uninephrectomised rats. RBF, mean arterial pressure (MAP), and renal vascular resistance (RVR) were measured in the following groups: (a) TAC (0.1 to 2.0 mg/kg/h, n = 3 approximately 6); CSA (20 and 50 mg/kg/h, n = 5); (b) L-NAME (10 mg/kg), an NO synthase inhibitor, 8 minutes prior to TAC (0.5 and 1.5 mg/kg/h, n = 5), or CSA (20 and 50 mg/kg/h, n = 5). Stable NO end-products, serum NO(2) and NO(3), were measured by the Griess method (n = 5). RESULTS: None of the parameters were changed by TAC alone, whereas TAC with L-NAME significantly reduced RBF (-28 +/- 7%) and increased RVR (46 +/- 17%) in a dose-dependent manner. CSA alone significantly reduced RBF (-37 +/- 6%) and increased RVR (69 +/- 22%) without any changes in MAP. The effects of CSA were enhanced by L-NAME. Serum concentration of NO(2) + NO(3) was significantly reduced by both L-NAME alone and CSA (50 mg/kg) (P < .05), while there were no changes with TAC (1.5 mg/kg). CONCLUSIONS: Blockade of NO production enhance the vasoconstrictive effect of CSA, and unmasked such an effect of TAC. These results suggest that the nephrotoxicity of CSA and TAC may involve the NO system.

Characterization of vascular endothelial growth factor (VEGF) in the uterine cervix over pregnancy: effects of denervation and implications for cervical ripening.

Bilateral neurectomy of the pelvic nerve (BLPN) that carries uterine cervix-related sensory nerves induces dystocia, and administration of its vasoactive neuropeptides induces changes in the cervical microvasculature, resembling those that occur in the ripening cervix. This study was designed to test the hypothesis that (a) the cervix of pregnant rats expresses vascular endothelial growth factor (VEGF) and components of the angiogenic signaling pathway [VEGF receptors (Flt-1, KDR), activity of protein kinase B, Akt (phosphorylated Akt), and endothelial nitric oxide synthase (eNOS)] and von Willebrand Factor (vWF) and that these molecules undergo changes with pregnancy, and (b) bilateral pelvic neurectomy (BLPN) alters levels of VEGF concentration in the cervix. Using RT-PCR and sequencing, two VEGF isoforms, 120 and 164, were identified in the rat cervix. VEGF, VEGF receptor-1 (Flt-1), eNOS, and vWF immunoreactivities (ir) were localized in the microvasculature of cervical stroma. Their protein levels increased during pregnancy but decreased to control levels by 2 days postpartum. VEGF receptor-2 (KDR)-ir was confined to the epithelium of the endocervix. BLPN downregulated levels of VEGF by a third. Therefore, the components of the angiogenic signaling pathway are expressed in the cervix and change over pregnancy. Furthermore, angiogenic and sensory neuronal factors may be important in regulating the dynamic microvasculature in the ripening cervix and may subsequently play a role in cervical ripening and the birth process.

Mucosal sulfhydryl compounds evaluation by in vivo electron spin resonance spectroscopy in mice with experimental colitis.

BACKGROUND: Sulfhydryl (SH) compounds are essential in maintaining mucosal integrity in the gastrointestinal tract. A decrease in colonic mucosal SH compounds affects the redox status of the mucosa, resulting in vulnerability to further attacks. Therefore, there is a strong need for in vivo evaluation of SH compounds in the colonic mucosa. AIMS: The aim of the current study was to establish a method of evaluating levels of SH compounds in the colonic mucosa of live animals before and after induction of colitis. METHODS: Murine experimental colitis was induced by instillation of trinitrobenzene sulphonic acid (TNBS) dissolved in 50% ethanol into the colon via the anus. For evaluation of mucosal SH compounds in the colon, 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (carbamoyl-PROXYL), a stable nitroxide radical, was instilled into the colonic lumen of live mice and the spin clearance rate was measured by L-band electron spin resonance (ESR) spectroscopy. RESULTS: Morphological study showed that mucosal damage was severe one or two days after TNBS instillation. The colonic mucosa started to regenerate at four days, and looked normal at seven days, after induction of colitis. The spin clearance rate of carbamoyl-PROXYL decreased significantly at 0.5, 1, 2, and 4 days after induction of colitis compared with mice before TNBS instillation. Surprisingly, although the colonic mucosa looked normal seven days after TNBS administration, the spin clearance rate still remained significantly slow. The spin clearance rate returned to normal 14 days after induction of colitis. The change in in vivo spin clearance rate was consistent with the time dependent change in mucosal reduced glutathione, a major component of SH compounds. CONCLUSION: The spin clearance rate obtained by L-band ESR spectroscopy in combination with carbamoyl-PROXYL can give an estimate of the level of colonic mucosal SH compounds in live animals and is useful for evaluating the mucosal defence system against oxidative stress.