Analgesic effects of the novel α2δ ligand mirogabalin in a rat model of spinal cord injury.

Mirogabalin, which is a novel ligand for the α2δ subunit of voltage-gated calcium channels, is under development for the treatment of pain associated with diabetic peripheral neuropathy and postherpetic neuralgia. Mirogabalin possesses unique binding characteristics to α2δ subunits and potent and long-lasting analgesic effects in peripheral neuropathic pain models. In the present study, we investigated the analgesic effects of mirogabalin in a rat model of spinal cord injury as an experimental animal model for central neuropathic pain. The spinal cord injury model was established by acute compression of the spinal cord at the T6/7 level with a microvascular clip in male rats. Twenty-eight days after spinal cord injury, the animals received the test compound orally, and the paw withdrawal threshold to mechanical stimulation was determined using the von Frey test at 0 (before administration), 2, 4, 6, 8, and 24 h after administration. The area under the curve of the paw withdrawal threshold (paw withdrawal threshold AUC) was also calculated. In rats subjected to spinal cord injury, mechanical allodynia was demonstrated by a decreased paw withdrawal threshold. A single oral administration of mirogabalin (2.5, 5, or 10 mg/kg) significantly increased the paw withdrawal threshold. The effects of mirogabalin were still significant 6 or 8 h after administration. The paw withdrawal threshold AUC was significantly higher in the treated animals than in the control group. In conclusion, mirogabalin showed potent and long-lasting analgesic effects in a rat model of spinal cord injury and may therefore provide effective pain relief for patients with central neuropathic pain.

Factors associated with a positive willingness to practise oral health care in the future amongst oral healthcare and nursing students.

OBJECTIVES: The purpose of this study was to identify the weak points in the knowledge and attitudes of first-year oral health care and nursing students towards oral health care and to identify the factors associated with their positive willingness to practise oral health care after becoming a health professional in order to develop oral healthcare curricula. MATERIALS AND METHODS: The subjects were 88 first-year dental students (DSs), 64 dental hygiene students (DHSs) and 119 nursing students (NSs) enrolled in schools in Japan, as of April 2017. A questionnaire was distributed to subjects in each school to assess their knowledge and attitudes towards oral health care. RESULTS: Less than half knew that oral health care was also provided in cancer hospitals, hospices, acute care hospitals, maternity wards and psychiatric wards. Only 46.2% knew that oral health care was effective in the prevention of aspiration pneumonia. The level of knowledge and attitudes in NSs regarding oral health care were likely to be lowest amongst the student groups. Only NSs' high interest towards oral health care was associated with their positive willingness to practise oral health care in the future although oral health students' high perceptions and interest regarding oral health care were associated with the willingness. CONCLUSION: This study showed oral healthcare and nursing students' weak points regarding their attitudes and knowledge of oral health care at early stages. Oral health academic staff and professionals should develop effective oral healthcare curricula for oral healthcare students and help nursing staff develop a collaborative nursing oral healthcare curriculum to motivate nursing students.

Postcomparison of [(18) F]-fluorodeoxyglucose uptake in the brain after short-term bright light exposure and no intervention.

OBJECTIVE: Bright light therapy is widely used as the treatment of choice for seasonal affective disorder. Nonetheless, our understanding of the mechanisms of bright light is limited and it is important to investigate the mechanisms. The purpose of this study is to examine the hypothesis that bright light exposure may increase [(18) F]-fluorodeoxyglucose (FDG) uptake in olfactory bulb and/or hippocampus which may be associated neurogenesis in the human brain. METHOD: A randomized controlled trial comparing 5-day bright light exposure + environmental light (bright light exposure group) with environmental light alone (no intervention group) was performed for 55 participants in a university hospital. The uptake of [(18) F]FDG in olfactory bulb and hippocampus using FDG positron emission tomography was compared between two groups. RESULTS: There was a significant increase of uptake in both right and left olfactory bulb for bright light exposure group vs. no intervention group. After adjustment of log-transformed illuminance, there remained a significant increase of uptake in the right olfactory bulb. CONCLUSION: The present findings suggest a possibility that 5-day bright light exposure may increase [(18) F]FDG in the right olfactory bulb of the human brain, suggesting a possibility of neurogenesis. Further studies are warranted to directly confirm this possibility.

Therapeutic window of lamotrigine for mood disorders: a naturalistic retrospective study.

INTRODUCTION: Lamotrigine is widely used for mood disorders including bipolar disorder and major depression, but its therapeutic levels have yet to be determined. This study was conducted to investigate the hypothesis that lamotrigine may have a therapeutic window for mood disorders. METHODS: 25 patients with mood disorders received lamotrigine for more than one year during which time plasma lamotrigine levels were measured at least once. Their mental state was retrospectively and regularly but blindly assessed using the Clinical Global Impression-Severity (CGI-S) scale. In order to investigate our hypothesis, we depicted the relationship between the last lamotrigine levels and the last CGI scores in 25 patients. If any, the potential therapeutic window was further investigated. RESULTS: The relationship between the last lamotrigine levels and the last CGI scores in the 25 patients indicated the presence of a therapeutic window of lamotrigine from 5 to 11 µg/mL. The repeated measures of ANOVA reached a significant tendency of the effects of lamotrigine levels within 5-11 µg/mL on better CGI-S scores, and the CGI-S scores at the last observation of the 15 patients whose lamotrigine levels were within 5-11 µg/mL were significantly better than those of 10 patients whose lamotrigine levels were not within 5-11 µg/mL. CONCLUSION: These findings suggest that lamotrigine may have a therapeutic window for patients with mood disorder from 5 to 11 µg/mL.

Utility of glucagon stimulation test in type 1 diabetes after pancreas transplantation.

BACKGROUND: Despite recent progress of immunosuppressive therapy with newly developed agents, long-term pancreatic graft survival after pancreas transplantation still remains low. Therefore, precise assessment of ß-cell function after pancreas transplantation is necessary. METHODS: Pancreatic ß-cell secretory activity was measured by means of the peripheral plasma fasting serum C-peptide (CPR) response to 1 mg of glucagon intravenously in 23 patients after pancreas transplantation. The utility of ΔCPR after injection was compared with other indices that reflect insulin secretion. RESULTS: When we performed the test, 6 patients still needed insulin injection after the transplantation. Mean CPR before and after glucagon intravenously were 1.9 ± 0.98 ng/mL and 4.6 ± 2.29 ng/mL, respectively. Fasting serum CPR, secretory unit of islet in transplantation (SUIT) index, and ΔCPR after glucagon injection were significantly different between insulin users and nonusers. During follow-up (501 ± 228 days), 3 patients could stop using insulin, and their increase of CPR (1.8 ± 0.5 ng/mL) was significantly higher than that in continuous insulin users (0.3 ± 0.3 ng/mL). CONCLUSION: Fasting CPR, SUIT index, and ΔCPR after glucagon injection could reflect ß-cell function for post-pancreas transplant patients, and glucagon stimulation test could give us additional information to predict insulin-free treatment.

Management of sleep-time masticatory muscle activity using stabilisation splints affects psychological stress.

To treat sleep bruxism (SB), symptomatic therapy using stabilisation splints (SS) is frequently used. However, their effects on psychological stress and sleep quality have not yet been examined fully. The objective of this study was to clarify the effects of SS use on psychological stress and sleep quality. The subjects (11 men, 12 women) were healthy volunteers. A crossover design was used. Sleep measurements were performed for three consecutive days or longer without (baseline) or with an SS or palatal splint (PS), and data for the final day were evaluated. We measured masseter muscle activity during sleep using portable electromyography to evaluate SB. Furthermore, to compare psychological stress before and after sleep, assessments were made based on STAI-JYZ and the measurement of salivary chromogranin A. To compare each parameter among the three groups (baseline, SS and PS), Friedman's and Dunn's tests were used. From the results of the baseline measurements, eight subjects were identified as high group and 15 as low group. Among the high group, a marked decrease in the number of bruxism events per hour and an increase in the difference in the total STAI Y-1 scores were observed in the SS group compared with those at baseline (P < 0·05). No significant difference was observed in sleep stages. SS use may be effective in reducing the number of SB events, while it may increase psychological stress levels, and SS use did not apparently influence sleep stages.

Characteristic mutations found in the ML0411 gene of Mycobacterium leprae isolated in Northeast Asian countries.

Genome analysis of Mycobacterium leprae strain Kyoto-2 in this study revealed characteristic nucleotide substitutions in gene ML0411, compared to the reference genome M. leprae strain TN. The ML0411 gene of Kyoto-2 had six SNPs compared to that of TN. All SNPs in ML0411 were non-synonymous mutations that result in amino acid replacements. In addition, a seventh SNP was found 41 bp upstream of the start codon in the regulatory region. The seven SNP sites in the ML0411 region were investigated by sequencing in 36 M. leprae isolates from the Leprosy Research Center in Japan. The SNP pattern in 14 of the 36 isolates showed similarity to that of Kyoto-2. Determination of the standard SNP types within the 36 stocked isolates revealed that almost all of the Japanese strains belonged to SNP type III, with nucleotide substitutions at position 14676, 164275, and 2935685 of the M. leprae TN genome. The geographical distribution pattern of east Asian M. leprae isolates by discrimination of ML0411 SNPs was investigated and interestingly turned out to be similar to that of tandem repeat numbers of GACATC in the rpoT gene (3 copies or 4 copies), which has been established as a tool for M. leprae genotyping. All seven Korean M. leprae isolates examined in this study, as well as those derived from Honshu Island of Japan, showed 4 copies of the 6-base tandem repeat plus the ML0411 SNPs observed in M. leprae Kyoto-2. They are termed Northeast Asian (NA) strain of M. leprae. On the other hand, many of isolates derived from the Okinawa Islands of Japan and from the Philippines showed 3 copies of the 6-base tandem repeat in addition to the M. leprae TN ML0411 type of SNPs. These results demonstrate the existence of M. leprae strains in Northeast Asian region having characteristic SNP patterns.

Synthesis and biological evaluation of a 6-aminofuro[3,2-c]pyridin-3(2H)-one series of GPR 119 agonists.

G protein-coupled receptor 119 (GPCR 119 (GPR119)) agonists have received considerable attention as a promising therapeutic option for treatment of type 2 diabetes mellitus. GPR119 is one of the GPCRs expressed in pancreatic islet ß-cells and its activation enhances stimulation of insulin secretion in a glucose-dependent manner. We have recently described a series of 6-amino-1H-indan-1-ones as potent, selective, and orally bioavailable GPR119 agonists with an amino group that plays important roles not only in their drug-like properties, such as high aqueous solubility, but also in their potent agonistic activity. However, many of these compounds displayed strong to moderate inhibition of human ether-à-go-go related gene channel. Attenuation of the basicity of the amino group by replacing the adjacent benzene ring with electron-deficient heteroaromatic rings provided several heterocyclic cores among which 6-aminofuro[3,2-c]pyridin-3(2H)-one was selected as a promising scaffold. Further optimization around the side chain moiety led to the discovery of 17i, which showed not only strong human GPR119 agonistic activity (EC50=14 nM), but also beneficial effects on gastric emptying and plasma total glucagon-like peptide-1 levels in mice.

DNA amplification using phi29 DNA polymerase validates gene polymorphism analysis from buccal mucosa samples.

Venous blood is currently the most common source of DNA for gene polymorphism screening; however, blood sampling is invasive and difficult to perform in general dental treatment. Buccal mucosa samples provide an alternative source of DNA, but it is frequently difficult to effectively amplify the DNA owing to the small amounts of sample material obtained. This study was performed to establish a method for performing total genomic DNA amplification from buccal mucosa samples using phi29 DNA polymerase. Total genomic DNA was isolated from buccal mucosa samples obtained from healthy subjects and was amplified using phi29 DNA polymerase. To determine the suitability of the extracted DNA for genotyping, polymerase chain reaction and restriction fragment length polymorphism analyses were performed for the IL-1 gene polymorphism. Genotyping of the IL-1 polymorphism was successful using the amplified DNA from a buccal mucosa, but genotyping was unsuccessful using the unamplified control because of low DNA purity. The method of extracting DNA from a buccal mucosa is painless, simple, minimally invasive, and rapid. Genomic DNA from a buccal mucosa can be amplified by phi29 DNA polymerase in sufficient quantity and quality to conduct gene polymorphism analyses.

Inhibition of the multiplication of Mycobacterium leprae by vaccination with a recombinant M. bovis BCG strain that secretes major membrane protein II in mice.

The ability of a recombinant Mycobacterium bovis BCG strain that secretes major membrane protein II (MMP-II) of Mycobacterium leprae (BCG-SM) to confer protection against leprosy was evaluated by use of a mouse footpad model. C57BL/6J mice intradermally inoculated with BCG-SM produced splenic T cells which secreted significant amounts of gamma interferon (IFN-gamma) in response to either the recombinant MMP-II, the M. leprae-derived membrane fraction, or the BCG-derived cytosolic fraction in vitro more efficiently than those from the mice infected with the vector control BCG strain (BCG-pMV, a BCG strain containing pMV-261). A higher percentage of CD8(+) T cells obtained from BCG-SM-inoculated mice than those obtained from BCG-pMV-inoculated mice produced intracellular IFN-gamma on restimulation with the M. leprae antigens. BCG-SM inhibited the multiplication of M. leprae in the footpads of C57BL/6J mice more efficiently than BCG-pMV. These results indicate that a BCG strain that secretes MMP-II could be a better vaccine candidate for leprosy.

Degradation of PEP-19, a calmodulin-binding protein, by calpain is implicated in neuronal cell death induced by intracellular Ca2+ overload.

Excessive elevation of intracellular Ca2+ levels and, subsequently, hyperactivation of Ca2+/calmodulin-dependent processes might play an important role in the pathologic events following cerebral ischemia. PEP-19 is a neuronally expressed polypeptide that acts as an endogenous negative regulator of calmodulin by inhibiting the association of calmodulin with enzymes and other proteins. The aims of the present study were to investigate the effect of PEP-19 overexpression on cell death triggered by Ca2+ overload and how the polypeptide levels are affected by glutamate-induced excitotoxicity and cerebral ischemia. Expression of PEP-19 in HEK293T cells suppressed calmodulin-dependent signaling and protected against cell death elicited by Ca2+ ionophore. Likewise, primary cortical neurons overexpressing PEP-19 became resistant to glutamate-induced cell death. In immunoprecipitation assay, wild type PEP-19 associated with calmodulin, whereas mutated PEP-19, which contains mutations within the calmodulin binding site of PEP-19, failed to associate with calmodulin. We found that the mutation abrogates both the ability to suppress calmodulin-dependent signaling and to protect cells from death. Additionally, the endogenous PEP-19 levels in neurons were significantly reduced following glutamate exposure, this reduction precedes neuronal cell death and can be blocked by treatment with calpain inhibitors. These data suggest that PEP-19 is a substrate for calpain, and that the decreased PEP-19 levels result from its degradation by calpain. A similar reduction of PEP-19 also occurred in the hippocampus of gerbils subjected to transient global ischemia. In contrast to the reduction in PEP-19, no changes in calmodulin occurred following excitotoxicity, suggesting the loss of negative regulation of calmodulin by PEP-19. Taken together, these results provide evidence that PEP-19 overexpression enhances resistance to Ca2+-mediated cytotoxicity, which might be mediated through calmodulin inhibition, and also raises the possibility that PEP-19 degradation by calpain might produce an aberrant activation of calmodulin functions, which in turn causes neuronal cell death.

Comparative study of attitudes to eating between male and female students in the People's Republic of China.

OBJECTIVE: This study was conducted to compare eating attitudes and lifestyles of male and female college students in China (Beijing). SUBJECTS AND METHODS: The subjects of this study consisted of 217 male and 177 female college students. They were asked to fill out the Eating Attitudes Test-26 (EAT-26) and a lifestyle questionnaire. RESULTS: The percentages of those above the cutoff point on the EAT-26 for abnormal eating attitudes were 4.7% of male and 6.2% of female students. Body perception of being fat (distorted body image) was the factor most associated with abnormal eating attitudes. DISCUSSION: Weight related concern was prevalent amongst the Chinese students. This suggests that the culture of the beauty of thinness is common among young students in Beijing, particularly female students.

Factors associated with abnormal eating attitudes among female college students in Japan.

OBJECTIVES: To determine the prevalence rates of abnormal eating attitudes and associated risk factors among female Japanese college students. SUBJECTS AND METHODS: The study population was 7812 female college students in Tokyo. They were asked to fill out the Japanese version of EAT-26 and lifestyle questionnaires. RESULTS: 5.1% of the subjects had a total EAT-26 score above the cutoff point (>20). Multiple regression analysis found the most important factors associated with abnormal eating attitudes were distorted body image, fewer sleeping hours, irregular meal habits, cigarette smoking and more exercise. DISCUSSION: The prevalence of abnormal eating attitudes among female college students in this study was lower than that of Japanese female high school students and lower than that reported for college students of both western and non-western countries. Our results suggest that body image dissatisfaction may be the most important factor associated with abnormal eating behavior.

Upregulation of T-cell-stimulating activity of mycobacteria-infected macrophages.

Macrophages are one of the most abundant host cells to come in contact with mycobacteria. However, the infected macrophages less efficiently stimulate autologous T cells in vitro. We investigated the effect of the induction of phenotypic change of macrophages on the host cell activities by using Mycobacterium leprae as a pathogen. The treatment of macrophages with interferon-gamma (IFN-gamma), GM-CSF and interleukin-4 deprived macrophages of CD14 antigen expression but instead provided them with CD1a, CD83 and enhanced CD86 antigen expression. These phenotypic features resembled those of monocyte-derived dendritic cells (DC). These macrophage-derived DC-like cells (MACDC) stimulated autologous CD4+ and CD8+ T cells when infected with M. leprae. Further enhancement of the antigen-presenting function and CD1a expression of macrophages was observed when treated with IFN-gamma. The M. leprae-infected and -treated macrophages expressed bacterial cell membrane-derived antigens on the surface and were efficiently cytolysed by the cell membrane antigen-specific CD8+ cytotoxic T lymphocytes (CTL). These results suggest that the induction of phenotypic changes in macrophages can lead to the upregulation of host defence activity against M. leprae.

Acetazolamide vasoreactivity in persistent vegetative state and vascular dementia evaluated by transcranial harmonic perfusion imaging and Doppler sonography.

UNLABELLED: To clarify the pathophysiological differences of the cerebrovascular reserve capacity in relation to cerebral cognitive impairments between persistent vegetative state (PVS) and vascular dementia (VD), we evaluated acetazolamide (ACZ) vasoreactivity testing by transcranial harmonic perfusion imaging (HPI) and Doppler sonography (TCD). METHODS: The subjects were 11 adult patients with severe cognitive impairments (4 PVS, 7 VD). TCD mean velocity (Vm) in the middle and posterior cerebral artery (MCA, PCA) and peak intensity (PI), area under curve (AUC), and mean transit time (MTT) analyzed by HPI time-intensity curves in the bilateral temporal lobe (TL), basal ganglia (BG), and thalamus (Th) were evaluated before and after ACZ administration. Resting values and relative changes (%delta) of TCD and HPI parameters were compared between PVS and VD. RESULTS: a) Resting values: There were no significant differences between the two groups. b) Vasoreactivity: 1) PVS: %delta Vm decreased in the left PCA and MCA. %delta PI/AUC/MTT decreased in the left TL and bilateral BG. 2) VD: %delta PI/AUC decreased in the right TL. %delta MTT tended to decrease in the right side. CONCLUSION: ACZ vasoreactivity tests by transcranial HPI and TCD allowed bedside, non-invasive, quantitative evaluation of the pathophysiology of cognitive function impairment and treatments, in relation to cerebrovascular reserve capacity in PVS and VD.

Acetazolamide vasoreactivity evaluated by transcranial harmonic perfusion imaging: relationship with transcranial Doppler sonography and dynamic CT.

UNLABELLED: To establish the reliability and clinical significance of transcranial ultrasonic harmonic perfusion imaging (HPI), we evaluated HPI's relationships with transcranial Doppler (TCD) and with dynamic CT (DCT), during acetazolamide (ACZ) vasoreactivity tests. METHODS: The subjects were 12 neurological patients. Time-averaged maximum velocity (TAVMX) in the middle (MCA) and posterior cerebral arteries was measured by TCD. Time-intensity (-density) curves of HPI (DCT) after bolus intravenous contrast injections were created in 3 regions of interest (ROI) on the axial plane involving the temporal lobe, basal ganglia, and thalamus on both sides. Assessments of vasoreactivity were based on comparisons conducted before and after ACZ administration in terms of: a) relative changes (%delta) of the TCD TAVMX, b) HPI contrast area enlargement, c) %delta of calculated cerebral blood volume and flow of the HPI and DCT. RESULTS: 1) TCD vasoreactivity decrease in the left MCA tended to correlate with lower frequency of HPI contrast area enlargement on the left side. 2) HPI and DCT vasoreactivity tended to be disturbed in the same side ROIs. CONCLUSIONS: Transcranial HPI achieves repeatable non-invasive bedside evaluation of cerebrovascular reserve capacity through qualitative and quantitative measurements of brain tissue perfusion, and will have clinical value in pathophysiological follow-up and therapeutic effectiveness determination of neurointensive care patients.

Acetazolamide vasoreactivity in vascular dementia and persistent vegetative state evaluated by transcranial harmonic perfusion imaging and Doppler sonography.

To clarify the pathophysiological differences of the cerebrovascular reserve capacity in relation to cerebral cognitive impairments between vascular dementia (VaD) and persistent vegetative state (PVS), we evaluated acetazolamide (ACZ) vasoreactivity testing by transcranial harmonic perfusion imaging (HPI) and Doppler sonography (TCD). Sixteen patients (age: 29-85 years; mean: 62) were divided into three groups: 7 VaD, 4 PVS, and 5 nondementia patients. Mean velocity (Vm) in the middle and posterior cerebral artery (MCA, PCA) was measured, and time-intensity curves of the HPI were evaluated at three regions of interest-the bilateral temporal lobe (TL), basal ganglia (BG), and thalamus (Th). TCD and HPI were evaluated before (resting state) and after ACZ administration, and vasoreactivity was compared among the three groups in terms of resting values and relative changes (%Delta) of Vm, peak intensity (PI), area under curve (AUC), and mean transit time (MTT). Results of the resting state: Decreased Vm, PI, and AUC of the VaD and PVS groups were more obvious in the right side. Results of vasoreactivity: In the PVS group, %DeltaVm decreased in the left PCA and MCA; %DeltaPI and %DeltaAUC decreased in the left TL and bilateral BG. In the VaD group, %DeltaPI and %DeltaAUC decreased in the right TL; %DeltaMTT tended to increase in the left side. ACZ vasoreactivity tests by transcranial HPI and TCD allowed bedside, noninvasive quantitative evaluation of the pathophysiology of cognitive function impairment in relation to cerebrovascular reserve capacity in VaD and PVS.

Reduced Fhit expression is associated with mismatch repair deficiency in human advanced colorectal carcinoma.

The Fragile Histidine Triad gene, encompassing the FRA3B fragile site at chromosome 3p14.2, is a candidate tumour suppressor gene involved in multiple tumour types including colorectal carcinomas. Recently, it has been reported that the Fragile Histidine Triad gene may be a target of damage in a fraction of mismatch deficient tumours. To explore this hypothesis, we analysed both Fragile histidine triad and mismatch repair protein (Msh2 and Mlh1) expression using immumohistochemical methods in 52 advanced colorectal carcinomas (19 well-, 17 moderately-, and 16 poorly-differentiated). In addition, we examined whether the Fragile histidine triad and mismatch repair protein expression correlated with p53 expression and clinicopathological findings. Significant loss or reduction of Fragile histidine triad expression was noted in 18 of the 52 (34.6%) advanced colorectal carcinomas: 2 (10.5%) well-differentiated, 3 (17.6%) moderately-differentiated, 13 (81.3%) poorly-differentiated carcinomas, the frequency being significantly higher in the latter than that in the former two (P<0.0001). Loss of mismatch repair protein (mainly, Mlh1) expression was detected in 21 of the 52 (40.4%) colorectal carcinomas. Moreover, reduced Fragile histidine triad expression was significantly associated with absence of mismatch repair protein expression in the advanced colorectal carcinomas (P<0.0001). However, the Fragile histidine triad and mismatch repair protein expression was not significantly associated with p53 expression. These results suggested that reduced Fragile histidine triad expression might be correlated with mismatch repair expression, but not with p53 expression.

The effects of CD40- and interleukin (IL-4)-activated CD23+ cells on the production of IL-10 by mononuclear cells in Graves' disease: the role of CD8+ cells.

The possible roles of CD8+ cells in the abnormal T cell-dependent B-cell activation in Graves' disease were investigated by analysing lymphocyte subsets in peripheral blood mononuclear cells (PBMC) and their production of soluble factors and cytokines such as IL-10 in patients with Graves' disease, Hashimoto's thyroiditis and normal controls. The PBMC were separated into CD8+ and CD8-depleted cells by magnetic separation columns, and cultured for 7 days with or without anti-CD40 monoclonal antibodies and IL-4. The culture supernatant was assayed for sCD23 and IL-10 using EIA, and the remaining cells were analysed by flow cytometry. Stimulation with anti-CD40 antibody together with IL-4 increased sCD23 levels and the number of CD23+ cells. The latter was further augmented by depletion of CD8+ cells. This combination of B cell stimulants increased production of IL-10 by PBMC from patients with Graves' disease. The CD40- and IL-4-activated production of IL-10 was decreased by CD8+ cell depletion. In contrast, constitutive production of IL-10 was increased after CD8+ cell depletion in a group of patients with low basal secretion levels (<35 ng/ml). It was, however, decreased in a group with higher basal production levels, but such a relationship was not found in the normal control group. Thus, T cell-dependent B-cell activation via a CD40 pathway activates CD23+ cells, leading to over-production of IL-10 and a shift of the Th1/Th2 balance to Th2 dominance, while CD8+ cells may suppress this activation to counteract the Th2 deviation in Graves' disease.