Modulation of pain perception through transcranial alternating current stimulation and its nonlinear relationship with the simulated electric field magnitude.

BACKGROUND: Oscillatory activities observed in multiple regions are closely associated with the experience of pain. Specifically, oscillatory activities within the theta- and beta-frequency bands, observed in the left dorsolateral prefrontal cortex (DLPFC), have been implicated in pain perception among healthy individuals and those with chronic pain. However, their physiological significance remains unclear. METHODS: We explored the modulation of pain perception in healthy individuals by theta- and beta-band transcranial alternating current stimulation (tACS) over the left DLPFC and examined the relationship between the modulation effect and magnitude of the electric field elicited by tACS in the left DLPFC using computational simulation. RESULTS: Our findings revealed that both theta- and beta-tACS increased the heat pain threshold during and after stimulation. Notably, the simulated electric field magnitude in the left DLPFC exhibited an inverted U-shaped relationship with the pain modulation effect for theta-tACS. CONCLUSIONS: Our study findings suggested that there would be an optimal electric field strength to produce a high analgesic effect for theta-tACS. SIGNIFICANCE: The application of theta- and beta-tACS interventions targeting the left DLPFC might facilitate the treatment of chronic pain. Furthermore, the attainment of effective pain modulation via theta-tACS over the DLPFC warrants the use of optimal stimulus intensity.

Inheritance of song and stridulatory peg number divergence between Chorthippus brunneus and C. jacobsi, two naturally hybridizing grasshopper species (Orthoptera: Acrididae).

Knowledge of the genetic basis of divergence in mating signal characters that contribute to reproductive isolation is critical to understanding speciation. Here, we describe a semi-automated system for characterizing grasshopper acoustic signals. We used this system to study the genetic basis of divergence in three male calling song components [echeme (EL), syllable (SL) and phrase (PL) lengths] between Chorthippus brunneus and C. jacobsi, two species of grasshoppers that hybridize in northern Spain. We also studied the number of pegs in the stridulatory file. For all characters, additive effects accounted for most of the genetic differentiation between species. However, the three song components also showed small but significant epistatic effects. No sex linkage was detected. Wright-Castle-Lande estimates of the minimum numbers of genetic factors underlying song and peg number divergence were low: peg number (n(e)=5.87+/-5.84), SL (n(e)=2.37+/-4.79) and PL (n(e)=0.87+/-0.86). On the other hand, EL appeared to be controlled by many genes. These results suggest that divergence in SL and PL might be driven by sexual selection whereas EL might not be under selection. This is consistent with experimental results on female song preference in related species. However, the fact that few factors appear to underlie the differences in peg number is surprising. Peg number is not closely related to song characteristics. It often varies between closely related grasshopper species and it has been assumed to be a neutral character. The biometrical approaches used here tend to underestimate the number of factors influencing a trait but provide valuable background for subsequent quantitative trait loci analyses.

Human LT-alpha-mediated resistance to autoimmune diabetes is induced in NOD, but not NOD-scid, mice and abrogated by IL-12.

Systemic administration of human lymphotoxin-alpha (hLT-alpha) made NOD mice resistant not only to spontaneous autoimmune type 1 diabetes mellitus but also to cyclophosphamide (CY)-induced diabetes and diabetes transfer by diabetic NOD spleen cells (triple resistance). In this study we analyzed the mechanisms of hLT-alpha-induced resistance, focusing on (1) hLT-alpha-induced resistance in the pancreatic beta cell, (2) CY-resistant suppressor cells, (3) suppression of induction or function of effector cells for beta cell destruction, or (4) others. To examine the first possibility in vitro, a NOD-derived beta cell line (MIN6N) was pretreated with hLT-alpha and then mixed with diabetic NOD spleen cells and MIN6N cell viability was measured. Treatment with hLT-alpha did not protect MIN6N cells but rather enhanced cytotoxicity. Next NOD-scid mice were pretreated with hLT-alpha and then transferred with diabetic NOD spleen. All the recipients developed diabetes. These results excluded the first possibility. The second possibility was also excluded by a cotransfer experiment, in which diabetic NOD spleen cells were cotransferred to NOD-scid mice with nontreated or hLT-alpha-treated nondiabetic NOD spleens. There was no significant difference in diabetes incidence between the two groups. To observe the third possibility, spleen cells of hLT-alpha-treated triple-resistant NOD mice were transferred to NOD-scid mice. Diabetes developed in the recipients, although the onset of diabetes was slightly delayed. Finally, hLT-alpha-treated triple-resistant NOD mice developed diabetes 1 week after daily IL-12 treatment. In summary, hLT-alpha administration made NOD mice resistant to effector cells for beta cell destruction. This resistance was induced in NOD, but not in NOD-scid, mice, indicating that lymphocytes were obligatory for the resistance. However, it was not mediated by transferable suppressor cells. Because effector cells were present in hLT-alpha-treated NOD spleen and the resistance was abrogated by IL-12 treatment, it is speculated that hLT-alpha treatment may have changed a local cytokine balance protective from beta cell destruction.

Adjuvant-induced improvement of glucose intolerance in type 2 diabetic KK-Ay mice through interleukin-1 and tumor necrosis factor-alpha.

We reported that administration of complete Freund's adjuvant (CFA) improved glucose tolerance test (GTT) results in obese diabetic KK-Ay mice. In this study, we investigated its mechanism. An injection with CFA remarkably improved GTT for more than a week in KK-Ay mice, although insulin response was not changed compared with saline controls. The hypoglycemic effect of insulin was significantly, but partially, potentiated in the CFA-treated mice compared with the controls, suggesting that CFA stimulated insulin-mediated and non-insulin-mediated glucose disposal. Improvement in the GTT with CFA was partially transferable to nontreated mice by peritoneal exudative cells, but not spleen or lymph node cells. Pretreatment with anti-interleukin (IL)-1 alpha and -1 beta antibodies or anti-tumor necrosis factor (TNF)-alpha antibody significantly abrogated the improvement in the GTT with CFA. The results indicate that CFA-induced improvement in glucose intolerance in KK-Ay mice was mediated at least by IL-1 and TNF-alpha.

The role of vitamin D3 receptor mRNA in the proliferation of hepatocellular carcinoma.

BACKGROUND/AIMS: 1,25-Dihydroxyvitamin D3 [1,25-(OH)2D3] exhibits effects on cell proliferation and differentiation. METHODOLOGY: We examined the anti-proliferative effect of 1,25-(OH)2D3 on human hepatocellular carcinoma cell lines (PLC/PRF/5, HCC-T) and the role of vitamin D receptors in modulating this effect. We also investigated the gene expression of vitamin D receptors in tissues from patients with hepatocellular carcinoma. RESULTS: 1,25-(OH)2D3 inhibited proliferation of PLC/PRF/5 cells that express prominent vitamin D receptor mRNA with time and dose dependent manner. On the other hand 1,25-(OH)2D3 had no anti-proliferative effect on hepatocellular carcinoma T cells in which gene expression of vitamin D receptor was little. We next examined vitamin D receptor gene expression in surgically obtained 10 hepatocellular carcinoma tissues by reverse transcriptase-polymerase chain reaction analysis. In all 10 cases, the level of vitamin D receptor mRNA in tumorous tissue was expressed on tumorous tissue. CONCLUSIONS: These results indicate that 1,25-(OH)2D3 may clinically exert its anti-proliferative effect through vitamin D receptors.

Modulation of tumor necrosis factor-alpha production with anti-hypertensive drugs.

It is well known that some anti-hypertensive drugs affect insulin sensitivity and that tumor necrosis factor-alpha (TNF-alpha) is a mediator of obesity-associated insulin resistance. In this study, we have investigated the effect of anti-hypertensive drugs, calcium (Ca) channel blockers (amlodipine, manidipine and nicardipine), an alpha(1)-blocker (doxazosin), a beta(1)-blocker (metoprolol), and a thiazide diuretic (hydrochlorothiazide), on lipopolysaccharide (LPS)-induced TNF-alpha production. TNF-alpha production, measured with a bioassay and an immunoassay, was evaluated both in vivo and in vitro, by utilizing mice and a human peripheral blood mononuclear cell culture, respectively. Nicardipine, or amlodipine, manidipine and doxazosin significantly inhibited TNF-alpha production in mice at doses more than one or ten times higher than those used clinically, respectively. On the other hand, metoprolol increased TNF-alpha production at doses of more than 10 times those used clinically, whereas hydrochlorothiazide did not alter production of the cytokine. The in vivo effects of these drugs were not necessary parallel to the in vitro effects. Because high doses of these drugs in mice correspond to clinical doses and effects in human, these actions may be related to beneficial and/or harmful effects of these drugs on TNF-alpha mediated diseases, including insulin resistance.

Immunological and virological predictors of outcome during interferon-alpha therapy of chronic hepatitis C.

Results from a multicentre, clinical trial of interferon-alpha2a (IFN-alpha2a) for the treatment of chronic hepatitis C are reported. Serum hepatitis C virus (HCV) RNA levels were monitored as follows: before, and 2 days after, the first administration of IFN-alpha2a; during and at the end of treatment; and 6 months after completion of therapy. Peripheral blood lymphocyte subpopulations were measured, by two-colour flow cytometry, before and 3 h after the first intramuscular (i.m.) administration of 9 mega units (MU) of IFN-alpha2a. Virological responders had a significantly lower pretreatment level of CD11+ CD8- lymphocytes. Biochemical responders had significantly lower pretreatment levels of CD11- CD8+, human leucocyte antigen (HLA) DR- CD4- and HLA DR- CD8+ populations, and a higher pretreatment HLA DR+ CD4- population. These pretreatment differences disappeared 3 h after the first i.m. administration of IFN-alpha2a. CD11- CD8+ and HLA DR+ CD8+ cell populations became significantly lower in virological responders 3 h after the first i. m. administration of IFN-alpha2a. HLA DR+ CD4+ cell populations were increased less in biochemical responders. Thus, T-lymphocyte subpopulations were different between responders and non-responders to IFN therapy and IFN-modulated host immunity. Multivariate analysis showed that the pretreatment CD11+ CD8- cell population was an independent predictive factor of response to therapy. On the other hand, patients whose serum HCV RNA cleared or decreased within the first 2 days of IFN-alpha2a therapy were more likely to achieve a virological response. This predictive factor, however, was not an independent factor by multivariate analysis. These results suggest that host immunity is an important factor in response to IFN therapy, and HCV clearance within the first 2 days is a good predictive factor of response.

A novel treatment for refractory primary biliary cirrhosis?

BACKGROUND/AIMS: Bezafibrate is naturally used for hyperlipidemia worldwide. In 1992 Day et al reported that the value of ALP and gamma-GTP in hyperlipidemia declined after administering bezafibrate orally. We conducted a study to investigate whether or not ALP and gamma-GTP in primary biliary cirrhosis which is characterized by the elevation of these enzymes improved after taking bezafibrate. METHODOLOGY: We administered bezafibrate additionally for 6 months to 13 patients with primary biliary cirrhosis (refractory PBC) whose liver enzymes (ALP or gamma-GTP) did not remain within normal range out of 21 patients treated by monotherapy of ursodeoxycholic acid for 18 months. RESULTS: At 2, 4, and 6 months, gamma-GTP level significantly decreased compared with that prior to the initiation of bezafibrate. At 4 and 6 months, ALP level significantly decreased compared with that prior to the initiation. At 2, 4 and 6 months, ALT level significantly decreased compared with that prior to the initiation. The value of IgG and IgM was also reduced significantly 6 months after the initiation. CONCLUSIONS: If the effectiveness of bezafibrate for primary biliary cirrhosis is confirmed histologically and by a randomized trial, a combination therapy of bezafibrate and ursodeoxycholic acid appear to be the medical treatment of choice for primary biliary cirrhosis in the future.

Inhibition of tumor necrosis factor-alpha with anti-diabetic agents.

It has recently been indicated that tumor necrosis factor-alpha (TNF-alpha) production is increased under chronic hyperglycemia and TNF-alpha has harmful effects on insulin sensitivity and possibly on chronic diabetic complications. Therefore it will be favorable for diabetes treatment if anti-diabetic agents also have anti-TNF-alpha activities. In this study, we have investigated effects of hypoglycemic sulfonylureas (gliclazide and glibenclamide) and a thiazolidinedione (troglitazone) on lipopolysaccharide-induced TNF-alpha production, which was evaluated by immunoassay and bioassay, in vivo using mice and partly in vitro using human peripheral blood mononuclear cells. Gliclazide significantly inhibited TNF-alpha production in vivo and also in vitro at a concentration of 10(-3) mol/l. However, glibenclamide had neither effect on TNF-alpha production nor action. On the other hand, troglitazone inhibited action rather than production of TNF-alpha in vivo. In vitro troglitazone (10(-4) mol/l) significantly reduced cytolytic activity of TNF-alpha against LM cells. These results indicate that gliclazide and troglitazone have inhibitory effect on TNF-alpha.

Novel therapeutic approach to primary biliary cirrhosis patients: anti-eosinophil strategy.

BACKGROUND/AIMS: Primary biliary cirrhosis (PBC) is a chronic cholestatic liver disease of unknown cause. Morphologically, PBC is characterized by eosinophil infiltration into the portal tract in recent studies. Pranlukast, a new drug, is a leukotriene antagonist, which suppresses eosinophil infiltration in atopic dermatitis or asthma. METHODOLOGY: In this study, pranlukast monotherapy was used to treat 12 patients with a diagnosis of PBC, classified as stage I or II according to Scheuer's classification on the basis of liver biopsy findings. RESULTS: An improvement in alkaline phosphatase (ALP) was observed beginning one month after the start of pranlukast therapy in all 12 patients. Improvement in ALP and gamma-GTP values was statistically observed at 1, 2, and 6 months after the start of treatment. IgG and IgM values improved in all 12 patients at 2 months and 6 months after the start of treatment. Absolute eosinophil counts improved at 6 months after the start of treatment. CONCLUSIONS: Given its efficacy and the absence of side effects, planlukast appears to be the medical treatment of choice for patients with early-stage PBC. But, a randomised, controlled, double-blind trial is urgently needed.

Gliclazide inhibits diabetic neuropathy irrespective of blood glucose levels in streptozotocin-induced diabetic rats.

N-acetylcysteine and pentoxifylline, free radical scavengers and inhibitors of tumor necrosis factor-alpha (TNF-alpha) production, inhibit the development of peripheral neuropathy in streptozotocin (STZ)-induced diabetic rats. This study was designed to elucidate the effect of gliclazide, an oral hypoglycemic sulfonylurea, on diabetic neuropathy, because it has been indicated to be a free radical scavenger and TNF-alpha inhibitor. Rats were fed with powder chow mixed with gliclazide or glibenclamide as a control ad libitum. Blood glucose levels and body weight were remarkably higher and lower in diabetic than in nondiabetic rats, respectively, while gliclazide and glibenclamide had no effect on these in both diabetic and nondiabetic rats throughout a 24-week experiment. Serum lipoperoxide levels and lipopolysaccharide (LPS)-induced serum TNF-alpha activities were significantly increased in diabetic rats, whereas these were significantly inhibited in gliclazide-treated rats. Motor nerve conduction velocity (MNCV) of the tibial nerve significantly slowed in diabetic rats compared with nondiabetic rats. On the other hand, the slowed MNCV was significantly inhibited in gliclazide-treated diabetic rats after 16 experimental weeks. Morphometric analysis showed that gliclazide prevented decreased myelinated fiber area (P < .05), increased fiber density (P < .001), and decreased axon/myelin ratio (P < .05) in diabetic rats. Glibenclamide treatment did not affect serum lipoperoxide, TNF-alpha, MNCV, or nerve morphology in this experiment. These results indicate that gliclazide has a beneficial effect on peripheral neuropathy in STZ-induced diabetic rats, irrespective of blood glucose levels.

Inhibitory effect of nicotinamide on in vitro and in vivo production of tumor necrosis factor-alpha.

Nicotinamide, a pellagra-preventive factor, has multiple functions such as inhibition of poly-ADP-ribose synthetase, inhibition of inducible nitric oxide synthase, free radical scavenging and suppression of major histocompatibility complex class II expression and ICAM-1 expression on endothelial cells. In addition to these, we have found an inhibitory effect of nicotinamide on production of tumor necrosis factor-alpha (TNF-alpha) in vitro and in vivo. Lipopolysaccharide (LPS)-induced in vitro TNF-alpha production by human peripheral blood mononuclear cells, measured by enzyme-linked immunosorbent assay (ELISA), was significantly inhibited with more than 1 x 10(-3) mol/l of nicotinamide, while interleukin-1-beta was not inhibited and interleukin-6 was slightly inhibited even with 10(-2) mol/l. Oral administration of nicotinamide with more than 62.5 mg/kg also significantly inhibited LPS-induced serum TNF-alpha production measured by ELISA and bioassay in Balb/c mice. Thus, nicotinamide has an inhibitory effect on TNF-alpha production that may be beneficial to TNF-alpha-mediated diseases.

Possible association between HLA antigens and the response to interferon in Japanese patients with chronic hepatitis C.

Correlation between the major histocompatibility complex class I antigens (HLA-A, -B and -C) and the elimination from serum of hepatitis C virus in patients with chronic hepatitis C has not been understood. We analyzed HLA phenotypes and their relationship to the efficacy of interferon treatment. Of the 172 patients who were treated with 9 million units of interferon-alpha 2a three times a week for 6 months, 54 patients were responders and 118 patients were non-responders. No significant difference was observed between the 172 patients and 199 healthy subjects with regard to the frequencies of HLA-A, -B and -C antigen phenotypes. However, HLA-B55, B62, CW3 and CW4 frequencies were significantly higher in responders than in non-responders to the interferon treatment. CW4 was found to link with B62, but other phenotypes were independent each other. Patients with HLA B55, B62 and CW3 had a significantly lower viral load, and showed a better response to interferon. These results suggest that HLA system does not have an influence on the evolution towards chronicity of the disease due to hepatitis C virus, but HLA B55, B62 or CW4, and CW3 may be a virus quantity-regulating factors which then affect to response to the interferon treatment, indicating that these HLA antigens in conjunction with a viral peptide is a key target antigen for cytotoxic T lymphocytes in patients with chronic hepatitis C.

Angiotensin converting enzyme inhibitors suppress production of tumor necrosis factor-alpha in vitro and in vivo.

It has been reported that angiotensin converting enzyme (ACE) inhibitors have beneficial effects on insulin resistance and congestive heart failure, in which elevations of serum tumor necrosis factor-alpha (TNF-alpha) level have been indicated. Therefore, in this study, we examined effect of ACE inhibitors on TNF-alpha production both in vitro and in vivo by using human blood mononuclear cells and mice, respectively. LPS (20 micrograms/ml)-induced in vitro TNF-alpha production, measured by bioassay and enzyme-linked immunosorbent assay, was significantly inhibited with captopril, delapril and cilazapril in a concentration of 10(-3) mol/l. A single, oral administration of captopril, delapril and cilazapril at more than 10-fold doses of common clinical use in man significantly inhibited LPS (2 mg/kg)-induced serum TNF-alpha activity in Balb/c mice. These results indicate that ACE inhibitors such as captopril, delapril and cilazapril have an inhibitory effect on TNF-alpha production not only in vitro as previously reported, but also in vivo, although relatively high concentrations and large doses were required in this study.

Effect of long-term treatment with complete Freund's adjuvant on KK-Ay mouse, a model of non-insulin-dependent diabetes mellitus.

Nonspecific stimulation with immunoadjuvants significantly improves glucose tolerance in animal models for non-insulin-dependent diabetes mellitus (NIDDM). In this study, we observed the effect of long-term treatment with complete Freund's adjuvant (CFA) on serum factors and histology of various organs in KK-Ay mice with NIDDM. The mice were injected with CFA weekly or every 2 weeks for 12 weeks. Glucose tolerance was significantly improved in the CFA-treated mice throughout the experiment. At the end of the experiment, hypertriglyceridemia was significantly reduced, but serum total protein, glutamic pyruvic transaminase, creatinine, and nonfasting insulin levels were not changed by the treatment. Fatty change of the liver and index of glomerular lesions of the kidney were significantly inhibited in the CFA-treated mice, whereas the pancreatic islet morphology remained unchanged. No toxic effect was observed by the CFA treatment. These results imply that the novel treatment with CFA could control NIDDM and inhibit the development of diabetic glomerular lesions in KK-Ay mice.

Keio multicenter trial in high-dose interferon-alpha 2b treatment for chronic hepatitis C. Keio Interferon-alpha 2b Study Group.

The efficacy of two different high-dose treatment of IFN-alpha 2b was evaluated in this study. Serum hepatitis C virus (HCV) RNA levels were semi-quantified by simplified reverse transcription-polymerase chain reaction. Seventy-one patients with chronic hepatitis C received 10 million units of IFN-alpha 2b daily for 2 weeks or twice a week for 24 weeks. Alanine aminotransferase (ALT) levels overall normalized in 78.1% and 51.6% of the cases at the end of the therapy and 6 months after that, respectively. HCV RNA disappeared in 71.9% and 35.7% of the patients at the end of the therapy and 6 months after that, respectively. There was no significant difference between the 2 different regimes. The efficacy of the treatment was fair in cases in which the pretreatment level of the viral amount was low. The results of this study indicate that daily administration of IFN in the first 2 weeks during 6-month course does not increase the efficacy of the therapy in such a high-dose treatment regime.

Reduced expression of c-Fos in female NOD mouse thymocytes and up-regulation with human lymphotoxin.

Previously we reported that the administration of human (h) lymphotoxin (h-LT) markedly protected NOD mice from insulin-dependent diabetes mellitus (IDDM) partly by affecting the generation phase of anti-islet effector cells, probably in the thymus. In this study, we investigated the effect of h-LT on the signal transduction of the mouse thymocytes by observing c-Fos expression in the thymocytes by using a flow cytometer. The intensity of c-Fos expression in whole thymocytes was significantly lower in the female NOD with a high incidence of diabetes than that in the male NOD mice with a low incidence of diabetes and than that in normal mice (P < 0.0001). The low c-Fos expression in the female NOD thymocytes was most prominent in CD3low thymocytes. c-Jun expression of the CD3low thymocytes was also lower in the female NOD mice. Administrations of h-LT, h-TNF, and h-IL-2, which has been reported to prevent IDDM in NOD mice by systemic administration, significantly up-regulated c-Fos expression in CD3low thymocytes. From these results, it is assumed that a relationship may exist between the high diabetes incidence and the defective c-Fos expression in female NOD mice and between the prevention of IDDM and the amelioration of the defective c-Fos expression with h-LT in female NOD mice.

Analysis of action mechanism of lymphotoxin in prevention of cyclophosphamide-induced diabetes in NOD mice.

Recently we reported that lymphotoxin (LT) administration protected non-obese diabetic (NOD) mice and BB rats from insulin-dependent diabetes mellitus. In this study we analysed the protection mechanism of LT by using cyclophosphamide (CY)-induced autoimmune diabetes in NOD mice. Pre-administration of 500 or 1000 U of LT three times a week between the age of 4 and 11-13 weeks before CY-treatment strongly inhibited CY-induced diabetes. This inhibition was reproduced by LT pre-administration at an earlier age (4 to 7 weeks) but not at a later age (8 to 11 or 10 to 12 wks). LT post-administration (100 U daily or 500 U twice a week) after CY-treatment at 14 weeks of age also strongly inhibited CY-induced diabetes. Spleen cell transfer was carried out using various combinations of donors and recipients. Spleen cell transfer from the non-diabetic mice, which were LT pre-administered between the age of 4 and 13 wks, to CY-treated mice did not significantly inhibit CY-induced diabetes, while transfer of the cells from the similarly treated mice to irradiated recipients did induce diabetes although the onset of diabetes was significantly delayed. Diabetes was not transferred by spleen cells from diabetic mice to LT pre-administered and CY-treated mice. LT administration did not change subpopulations and adhesion molecule expressions of the spleen lymphocyte. Taken together, these results suggest that LT protects NOD mice from CY-induced diabetes by making the mice resistant to autoimmune diabetes and possibly by suppressing anti-islet effector cells, but not by inducing adoptively transferable suppressor cells, although the precise mechanisms still remain to be elucidated.

Quantitatively measured photorefractive sensitivity of proton-exchanged lithium niobate, proton-exchanged magnesium oxide-doped lithium niobate, and ion-exchanged potassium titanyl phosphate waveguides.

The photorefractive sensitivities of proton-exchanged lithium niobate waveguides and Rb-ion-exchanged potassium titanyl phosphate waveguides are quantitatively measured, and their influence on waveguide applications is estimated.