Detection of retinal dysfunction induced by HCN channel inhibitors using multistep light stimulus and long-duration light stimulus ERG in rats.

Ivabradine, a hyperpolarization-activated cyclic nucleotide-gated (HCN) channel inhibitor, has been reported to induce photosensitivity-related visual disturbances such as phosphene in humans. Ivabradine-induced visual disturbances are caused by inhibition of HCN channels in the retina, and the mechanisms have been verified using HCN channel knockout mice and electroretinography (ERG). However, in rats, classical ERG using single flash light stimulus with standard analyses of waveform amplitude and latency has not revealed abnormal retinal function after administration of ivabradine. To verify whether retinal dysfunction after ivabradine administration was detectable in rats, we performed ERG using multistep flash light stimulation at the time when plasma concentration of ivabradine was high. Furthermore, the mechanism of the change in the waveform that appeared after the b-wave was investigated. Ivabradine and cilobradine, a selective HCN channel inhibitor, were administered subcutaneously to rats at 4-40 mg/kg as a single dose, and flash or long-duration ERG recordings at each light stimulus luminance were conducted 1.5 h after administration. Plasma and retinal concentrations of both compounds were measured immediately after the ERG recordings. In the flash ERG, prolongation of a- and/or b-wave latencies were detected at each light stimulus, and dose-dependent waveform changes after the b-wave were recorded at the specific light stimulus luminance for both compounds. These ERG changes increased in response to increasing plasma and retinal concentrations for both ivabradine and cilobradine. In the long-duration light stimulus ERG, a change in the waveform of the b-wave trough and attenuation of the c-wave were recorded, suggesting that the feedback control in the photoreceptor cells may be inhibited. This study revealed that the retinal dysfunction by HCN channel inhibitors in rats can be detected by multistep light stimulus ERG. Additionally, we identified that the inhibition of feedback current and the sustained responses in the photoreceptor cells cause the retinal dysfunction of HCN channel inhibitors in rats.

Exposure of female NZBWF1 mice to imiquimod-induced lupus nephritis at an early age via a unique mechanism that differed from spontaneous onset.

Systemic lupus erythematosus (SLE) is a chronic inflammatory and representative autoimmune disease. Extremely complicated and multifactorial interactions between various genetic factors and individual susceptibility to environmental factors are involved in the pathogenesis of SLE. Several studies have reported that mutation and activation of toll-like receptor (TLR) 7 are involved in the onset of autoimmunity, including SLE. Thus, we investigated the response of SLE-prone mice to continuous environmental factors, particularly TLR7 agonist exposure, and changes in their phenotypes. Female and male NZBWF1 (BWF1) mice were treated from 20 weeks of age with a TLR7 agonist, imiquimod (IMQ), 3 times weekly for up to 12 weeks. IMQ-exposed female BWF1 mice showed worsened lupus nephritis. However, autoantibody production was not enhanced in IMQ-exposed female BWF1 mice. The Th1 cytokine expression was upregulated in the kidney of IMQ-treated mice. In IMQ-exposed BWF1 mice, neutralization of IFN-γ suppressed early-phase lupus nephritis. Additionally, in male BWF1 mice IMQ exposure induced minor aggravation of lupus nephritis. These results suggest that the induction of aggravated lupus nephritis by TLR7 agonist exposure was related to the expression of IFN-γ via acute TLR7 signal-induced renal inflammation, and that the involvement of genetic factors associated with a predisposition to SLE is also essential. Thus, the activation of TLR7 signaling by exposure to environmental factors may upset the balance of factors that maintain SLE remission. We hypothesize that the inhibition of TLR7 signaling and IFN-γ signaling is effective for preventing the onset and flare and maintaining remission of lupus nephritis.

Extended application of the rapid post-mortem test kit for bovine spongiform encephalopathy to chronic wasting disease.

Chronic wasting disease (CWD) is a prion disease affecting cervid species primarily in the United States of America and Canada; however, it is now emerging in Scandinavian countries. Although CWD cases have not been reported in Japan, in case of a CWD outbreak occuring, it is critical to prepare for testing a large number of specimens. The present study showed that a rapid post-mortem test kit, which is used for bovine spongiform encephalopathy surveillance in Japan, is valid for the detection of CWD prion.

Metformin repositioning in rheumatoid arthritis.

OBJECTIVES: Metformin is a known therapeutic agent for diabetes. Recently, several reports suggested the possibility of improvement in autoimmune disease and malignancy conditions through the effect of metformin on the immune system. Although there have been reports on the therapeutic effects of metformin on mouse models of collagen-induced arthritis, simulating human rheumatoid arthritis (RA), the effect of metformin on human RA remains unknown. Therefore, we investigated the inhibitory effect of metformin on the pathogenesis of human RA in vitro. METHODS: Osteoclastogenesis was evaluated with or without metformin. through tartrate-resistant acid phosphatase staining, osteoclast-specific enzyme expression analysis, and a bone resorption assay. Human fibroblast-like synoviocyte MH7A cells were stimulated with TNF-α, and the expression of proinflammatory cytokines and protease and growth factor genes was evaluated with or without metformin. Metformin has been used to evaluate their potential modulatory effects on cells treated with TNF-α. Moreover, we examined angiogenesis by performing a tube formation assay using human umbilical vein endothelial cells (HUVECs) with or without metformin. RESULTS: Osteoclastogenesis was suppressed in the presence of metformin, and the expression of osteoclast-specific genes was reduced. The TNF-α-induced expression of inflammatory cytokines and protease and growth factor genes in MH7A cells was downregulated by metformin. Additionally, the induced formation of tubular networks in HUVECs was also disrupted following treatment with metformin. CONCLUSIONS: These results suggest that metformin might improve the pathogenesis of RA, including joint inflammation and destruction. Thus, metformin might be utilised as a potential therapeutic agent in the treatment of RA.

Social defeat stress exacerbates atopic dermatitis through downregulation of DNA methyltransferase 1 and upregulation of C-C motif chemokine receptor 7 in skin dendritic cells.

DNA methylation is an epigenetic modification that regulates gene transcription. DNA methyltransferase 1 (DNMT1) plays an important role in DNA methylation. However, the involvement of DNMT1 and DNA methylation in the pathogenesis of atopic dermatitis (AD) remains unclear. In this study, microarray analysis revealed that peripheral blood mononuclear cells of AD patients with low DNMT1 expression (DNMT1-low) highly expressed dendritic cell (DC) activation-related genes. Also, DNMT1-low AD patients exhibited a higher itch score compared to AD patients with high DNMT1 expression (DNMT1-high). By using an AD-like mouse model induced by the application of Dermatophagoides farinae body ointment, we found that Dnmt1 expression was decreased, while the expression of C-C chemokine receptor type 7 (Ccr7) was upregulated in mouse skin DCs. Furthermore, mice exposed to social defeat stress exhibited Dnmt1 downregulation and Ccr7 upregulation in skin DCs. Additionally, dermatitis and itch-related scratching behavior were exacerbated in AD mice exposed to stress. The relationship between low DNMT1 and itch induction was found in both human AD patients and AD mice. In mouse bone marrow-derived DCs, Ccr7 expression was inhibited by 5-aza-2-deoxycytidine, a methylation inhibitor. Furthermore, in mouse skin DCs, methylation of CpG sites in Ccr7 was modified by either AD induction or social defeat stress. Collectively, these findings suggest that social defeat stress exacerbates AD pathology through Dnmt1 downregulation and Ccr7 upregulation in mouse skin DCs. The data also suggest a role of DNMT1 downregulation in the exacerbation of AD pathology.

MicroRNA-766-3p Contributes to Anti-Inflammatory Responses through the Indirect Inhibition of NF-κB Signaling.

MicroRNA (miRNA) is small RNA of 20 to 22 nucleotides in length and is stably present in plasma. Regulating the expression of miRNA taken into cells has been suggested as a general therapeutic approach. We identified the novel anti-inflammatory miRNA hsa-miR-766-3p and investigated its biological function in human rheumatoid arthritis (RA) fibroblast-like synoviocyte MH7A cells. To verify the function of the miRNA present in the plasma of RA patients, we performed a comprehensive analysis of the miRNA expression during abatacept treatment and identified eight miRNAs with significantly altered expression levels. Among these eight miRNAs, miR-766-3p was found to have a clear function. The expression of inflammatory genes in response to inflammatory stimuli was suppressed in MH7A transduced with miR-766-3p. We showed that miR-766-3p indirectly reduced the activation of NF-κB and clarified that this mechanism was partially involved in the reduction of the mineralocorticoid receptor expression. In addition, the inflammatory responses were suppressed in other types of cells. These results indicate the novel function of miR-766-3p, findings that may aid in the development of therapies to suppress inflammation, not only in RA but also in other diseases.

JAK inhibitor has the amelioration effect in lupus-prone mice: the involvement of IFN signature gene downregulation.

BACKGROUND: We previously reported that JAK-STAT-pathway mediated regulation of IFN-regulatory factor genes could play an important role in SLE pathogenesis. Here, we evaluated the efficacy of the JAK inhibitor tofacitinib (TOFA) for controlling IFN signalling via the JAK-STAT pathway and as a therapeutic for SLE. RESULTS: We treated NZB/NZW F1 mice with TOFA and assessed alterations in their disease, pathological, and immunological conditions. Gene-expression results obtained from CD4+ T cells (SLE mice) and CD3+ T cells (human SLE patients) were measured by DNA microarray and qRT-PCR. TOFA treatment resulted in reduced levels of anti-dsDNA antibodies, decreased proteinuria, and amelioration of nephritis as compared with those observed in control animals. Moreover, we observed the rebalance in the populations of naïve CD4+ T cells and effector/memory cells in TOFA-treated mice; however, treatment with a combination of TOFA and dexamethasone (DEXA) elicited a stronger inhibitory effect toward the effector/memory cells than did TOFA or DEXA monotherapy. We also detected decreased expression of several IFN-signature genes Ifit3 and Isg15 in CD4+ from SLE-prone mice following TOFA and DEXA treatment, and IFIT3 in CD3+ T cells from human patients following immunosuppressant therapy including steroid, respectively. CONCLUSION: Modulation of type I IFN signalling via JAK-STAT inhibition may exert a beneficial effect in SLE patients, and our results suggest that TOFA could be utilised for the development of new SLE-specific therapeutic strategies.

Intestinal perforation due to hemorrhagic Cytomegalovirus enteritis in a patient with severe uncontrolled lupus nephritis: a case and review of the literature.

A 31-year-old woman with systemic lupus erythematosus and lupus nephritis was treated with prednisone and immunosuppressants. After her lupus nephritis symptoms worsened, both high-dose steroid and cyclophosphamide pulse therapy were administered. The patient developed an intestinal perforation, and laparoscopic Hartmann's surgery was performed on the sigmoid colon. Serum Cytomegalovirus (CMV) antigen C7HRP was detected, and the patient was diagnosed with CMV colitis and underwent a colon resection. Severe hematochezia continued despite ganciclovir administration, and the patient underwent laparoscopic total colectomy and partial ileostomy. CMV enteritis should be considered in patients treated with prednisone and immunosuppressants and those who have abdominal pain and hematochezia. Immunocompromised patients with intestinal perforation due to CMV enteritis have a poor prognosis. We report a case with along with the results of a literature review.

Rapid onset of small intestinal perforation after successful steroid treatment in eosinophilic granulomatosis with polyangiitis.

Eosinophilic granulomatosis with polyangiitis (EGPA) is a disorder characterized by extravascular granulomas, hypereosinophilia, and pulmonary and systemic small-vessel vasculitis. Bowel perforation is a rare but often fatal complication of EGPA. In the present report, we describe a case of small intestinal perforation in a patient with EGPA. Through various examinations, we confirmed the presence of EGPA, and the patient responded well to steroid therapy. However, as the patient's condition subsequently worsened, the small intestine was consequently resected. The patient's overall condition improved thereafter. Thus, we believe that careful attention should be paid to intestinal symptoms and perforation in patients with EGPA.

Inhibition of connective tissue growth factor ameliorates disease in a murine model of rheumatoid arthritis.

OBJECTIVE: We have shown that connective tissue growth factor (CTGF) plays an important role in the pathogenesis of rheumatoid arthritis (RA). This study was undertaken to evaluate the effects of blockade of the CTGF pathway on the development of collagen-induced arthritis (CIA) in mice. METHODS: Arthritis was induced in DBA/1J mice by immunization with a combination of type II collagen (CII) and Freund's complete adjuvant. We evaluated the development of arthritis in mice with CIA left untreated versus treated with neutralizing anti-CTGF monoclonal antibody (mAb). RESULTS: Inhibition of CTGF in mice treated with neutralizing anti-CTGF mAb significantly ameliorated arthritis compared to the untreated mice with CIA. Serum levels of matrix metalloproteinase 3 were reduced by anti-CTGF mAb treatment. Moreover, blockade of CTGF decreased interleukin-17 expression on purified CD4+ T lymphocytes. Although the expression of the retinoic acid receptor-related orphan receptor γt gene was not suppressed by anti-CTGF mAb treatment, that of interferon regulatory factor 4 (IRF-4) and IκBζ (Nfkbiz), which are other important molecules for the differentiation of Th17 cells, was suppressed. In addition, blockade of CTGF inhibited pathologic proliferation of T lymphocytes in response to CII restimulation in vitro. Moreover, aberrant osteoclastogenesis in mice with CIA was restored by anti-CTGF mAb treatment. CONCLUSION: Our findings indicate that blockade of CTGF prevents the progression of arthritis in mice with CIA. Anti-CTGF mAb treatment suppresses pathologic T cell function and restores aberrant osteoclastogenesis in mice with CIA. CTGF may become a new target for the treatment of RA.

Improved seizure liability detection by combining rat hippocampal brain slice electrophysiology with in vivo behavior observation following intracerebroventricular drug administration.

An adverse effect of drug candidates, seizure is a serious issue in drug development. Improving evaluation systems for seizure liability is crucial for selecting good candidates. Firstly, in vitro electrophysiological measurement by a multielectrode array system in rat hippocampal brain slices was employed to confirm an increase in electrically evoked population spike (PS) area, the occurrence of multiple population spikes (MPSs), and thereby the seizure liability of five positive control chemicals: picrotoxin, 4-aminopyridine, pentylenetetrazole, penicillin G, and chlorpromazine. Aspirin, a negative control, did not affect PS area or generate MPSs. Furthermore, baclofen, an anticonvulsant drug, decreased PS area and inhibited the increase in PS area or occurrence of MPSs induced by picrotoxin. A comparative study of seizure liability among carbapenem antibiotics revealed that tienam > carbenin > omegacin and finibax. Despite leading to a strong decrease in PS area, physostigmine, cisplatin, and paroxetine still produced MPSs. Therefore, the increase in PS area or the occurrence of the MPS are considered significant evaluation parameters for seizure liability. In contrast, the in vitro electrophysiological measurement could not detect the seizure liability of diphenhydramine or fluvoxamine. A follow-up study of in vivo mouse behavioral change induced by intracerebroventricular administration of these drugs clearly detected convulsions. The in vitro electrophysiological study using hippocampal brain slices combined with in vivo behavior observation study of drug candidates administered by intracerebroventricular injection can implement to assess the seizure liability of even small amounts, especially in the early stages of drug development.

Optimal time of starting tocilizumab in acute phase of adult-onset Still's disease and comparison of its efficacy with that of methotrexate: a case series and a review of the literature.

Adult-onset still's disease is a rare condition that is generally treated by glucocorticoids. Importantly, due to the limited established treatments, glucocorticoid-refractory cases are particularly difficult to treat. Between December 2009 and August 2022, nine patients with adult-onset Still's disease were treated with tocilizumab (tocilizumab group). The therapeutic efficacy and safety of tocilizumab initiation in the acute phase were evaluated in cases of initial onset and recurrence. We also compared the efficacy of tocilizumab with that of methotrexate (methotrexate group, n = 13), which has been the drug of choice for adjunctive therapy. Tocilizumab demonstrated the expected efficacy in all four patients who received it at relapse and in three of the five patients who received it at the initial onset. However, two patients developed macrophage activation syndrome following treatment. A comparison of treatment effects between the methotrexate and tocilizumab groups revealed that the ferritin and C-reactive protein levels, severity score, and glucocorticoid doses decreased over time in both groups; nonetheless, the tocilizumab group experienced a more stable effect. Tocilizumab is undoubtedly a valuable treatment option for adult-onset Still's disease, especially when administered at relapse. This suggests that it shows both high safety and good efficacy. Nevertheless, a larger sample size is required to validate the efficacy and safety of tocilizumab compared with those of the existing alternatives. Key Points • We examined the significance of TCZ in terms of therapeutic efficacy, reduction in glucocorticoid usage, and safety in patients with AOSD. • We compared the therapeutic efficacy of TCZ with that of MTX, which is often used to treat glucocorticoid-resistant AOSD. • TCZ is undoubtedly a valuable treatment option for AOSD, especially when administered at relapse, suggesting both high safety and good efficacy.

Competition and disturbance affect elevational distribution of two congeneric conifers.

Climatic change will affect elevational vegetation distribution because vegetation distribution is related to thermal conditions. However, how elevational species distributions are determined by biotic and abiotic factors is not clear. The long-term plot census along an elevational gradient is indispensable to clarify mechanisms of elevational distribution of tree species. Two congeneric conifers, the less shade-tolerant Abies veitchii and shade-tolerant A. mariesii, dominate at low and high elevations, respectively, in the subalpine zone in Japan. This study investigated the population dynamics of the two species at three elevations (low, middle, high) for 13 years to examine why the two species dominated the different elevations from the viewpoints of competition and disturbance. This study showed that growth and survival rates were not highest at the most dominant elevations for each species. At the high elevation where A. mariesii dominated and small disturbances frequently occurred, the recruitment rate of A. mariesii was highest among the three elevations and that of A. veitchii was largely decreased by tree competition. However, A. veitchii was dominant earlier than A. mariesii at the low elevation after large disturbances by the high growth rate of individual trees. Therefore, A. mariesii was superior to A. veitchii at the high elevation because of its high recruitment rate and large reduction of recruitment of A. veitchii due to competition, while A. veitchii was superior to A. mariesii at the low elevation after large disturbances because of higher growth rate than A. mariesii. It is suggested that the elevational distributions of the two species were determined by elevational changes in population dynamics in relation to competition and disturbance. Long-term observational studies of forest dynamics among various elevations are indispensable to predict the effects of climatic change on vegetation distribution.

Complete Genome Sequence of a Genotype 3 Atypical Porcine Pestivirus Strain (OKN/2021) from Okinawa Prefecture, Japan.

We report the complete genome sequence of atypical porcine pestivirus (APPV) OKN/2021, which was sampled in the Okinawa Prefecture, Japan. The sequence bears the closest resemblance to another previously detected Japanese genotype 3 APPV sequence. This genome sequencing will help researchers in Japan learn more about the virus epidemiology and evolutionary characteristics.

Type 1 interferon suppresses expression and glucocorticoid induction of glucocorticoid-induced leucine zipper (GILZ).

SLE is a systemic multi-organ autoimmune condition associated with reduced life expectancy and quality of life. Glucocorticoids (GC) are heavily relied on for SLE treatment but are associated with detrimental metabolic effects. Type 1 interferons (IFN) are central to SLE pathogenesis and may confer GC insensitivity. Glucocorticoid-induced leucine zipper (GILZ) mediates many effects of GC relevant to SLE pathogenesis, but the effect of IFN on GC regulation of GILZ is unknown. We performed in vitro experiments using human PBMC to examine the effect of IFN on GILZ expression. JAK inhibitors tofacitinib and tosylate salt were used in vivo and in vitro respectively to investigate JAK-STAT pathway dependence of our observations. ChiP was performed to examine glucocorticoid receptor (GR) binding at the GILZ locus. Several public data sets were mined for correlating clinical data. High IFN was associated with suppressed GILZ and reduced GILZ relevant to GC exposure in a large SLE population. IFN directly reduced GILZ expression and suppressed the induction of GILZ by GC in vitro in human leukocytes. IFN actions on GILZ expression were dependent on the JAK1/Tyk2 pathway, as evidenced by loss of the inhibitory effect of IFN on GILZ in the presence of JAK inhibitors. Activation of this pathway led to reduced GR binding in key regulatory regions of the GILZ locus. IFN directly suppresses GILZ expression and GILZ upregulation by GC, indicating a potential mechanism for IFN-induced GC resistance. This work has important implications for the ongoing development of targeted GC-sparing therapeutics in SLE.

Recurrence in long-term survivor of anti-MDA5 antibody-positive clinically amyopathic dermatomyositis: case series and literature review.

Anti-MDA5 antibody-positive clinically amyopathic dermatomyositis (CADM) is often complicated by rapidly progressive interstitial lung disease and is associated with poor prognosis. However, even though recurrence is reported to be infrequent if successful medical treatment is administered, the long-term prognosis remains unclear. In this case report, we examined the clinical features and treatment details of three patients with anti-MDA5 antibody-positive CADM with multiple recurrences during long-term survival at Juntendo University Urayasu Hospital. Of the three patients, two failed to convert to an anti-MDA5 antibody-negative status, and one patient died. One of the remaining patients experienced two relapses but eventually tested negative for anti-MDA5 antibodies and showed a relatively stable clinical course. Although cases of recurring anti-MDA5 antibody-positive CADM rarely occur, they may occasionally be fatal. The prognosis for anti-MDA5 antibody-positive CADM has improved over time owing to its establishment as a disease. However, further information and research is necessary to ascertain its long-term prognosis.

A novel RyR1-selective inhibitor prevents and rescues sudden death in mouse models of malignant hyperthermia and heat stroke.

Mutations in the type 1 ryanodine receptor (RyR1), a Ca2+ release channel in skeletal muscle, hyperactivate the channel to cause malignant hyperthermia (MH) and are implicated in severe heat stroke. Dantrolene, the only approved drug for MH, has the disadvantages of having very poor water solubility and long plasma half-life. We show here that an oxolinic acid-derivative RyR1-selective inhibitor, 6,7-(methylenedioxy)-1-octyl-4-quinolone-3-carboxylic acid (Compound 1, Cpd1), effectively prevents and treats MH and heat stroke in several mouse models relevant to MH. Cpd1 reduces resting intracellular Ca2+, inhibits halothane- and isoflurane-induced Ca2+ release, suppresses caffeine-induced contracture in skeletal muscle, reduces sarcolemmal cation influx, and prevents or reverses the fulminant MH crisis induced by isoflurane anesthesia and rescues animals from heat stroke caused by environmental heat stress. Notably, Cpd1 has great advantages of better water solubility and rapid clearance in vivo over dantrolene. Cpd1 has the potential to be a promising candidate for effective treatment of patients carrying RyR1 mutations.

Anti-proteasome activator 28alpha is a novel anti-cytoplasmic antibody in patients with systemic lupus erythematosus and Sjögren's syndrome.

We evaluated the extent to which anti-proteasome activator (PA) 28alpha antibodies act as anti-cytoplasmic antibodies in systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS). Sera from 46 SLE patients without SS, 11 SLE patients with SS, and 45 primary SS patients were tested. Using anti-PA28alpha and anti-PA28gamma (Ki) antibodies purified from nitrocellulose membranes onto which recombinant PA28alpha and Ki had been transferred, the cellular distributions of the targeted antigens were analyzed immunohistochemically. In addition, the incidence of anti-PA28alpha antibodies was compared with those of other anti-cytoplasmic antibodies. Immunofluorescent staining showed that purified anti-PA28alpha antibodies reacted with the cytoplasm of HEp-2 cells, whereas purified anti-Ki antibodies reacted with nucleoplasm. Among the 15 SLE patients without SS, the six SLE patients with SS, and the 30 primary SS patients who were anti-cytoplasmic-antibody positive, anti-SS-A/Ro antibodies were the most frequently detected (53, 67, and 70%, respectively); anti-PA28alpha antibodies were, respectively, detected in 33, 50, and 40% of those patient groups, incidences that were higher than those of anti-ribosomal P, anti-smooth muscle and anti-mitochondrial M2 antibodies. These results show that anti-PA28alpha antibodies are major anti-cytoplasmic antibodies in patients with SLE and SS, and the distinct cellular distributions of PA28alpha and Ki suggest these proteins are associated with different cellular functions.

Availability of multistep light stimulus method for evaluation of visual dysfunctions.

In the field of drug safety research, electroretinography (ERG) is commonly conducted according to the international standard method propounded by the International Society for Clinical Electrophysiology of Vision (ISCEV) in recent years. However, various ERG methods other than the ISCEV standard method are also utilized depending on the intended purpose of the evaluation. In this study, we investigated the availability of a multistep light stimulus method for evaluation of rod function in Long-Evans rats using sildenafil, which is known to inhibit phosphodiesterase 6 (PDE6) in phototransduction and induce visual dysfunctions in humans. Sildenafil was orally administered to female Long-Evans rats at doses of 15, 50, and 150 mg/kg, and ERG was recorded at 1.5 h after treatment. In addition to a - 2.0 log cd·s/m2 stimulus corresponding to dark-adapted 0.01 ERG in the ISCEV standard method, light stimulus intensities of -4.5, -4.0, -3.0, -1.0, 0.0, and +1.0 log cd·s/m2 were applied for multistep ERG recording. The amplitude and implicit time of the a-wave were decreased and prolonged, respectively, at doses of ≥50 mg/kg. The amplitude and implicit time of the b-wave were decreased and prolonged, respectively, at all doses. However, the b-wave at 15 mg/kg was only diminished or attenuated at ≤ - 3.0 log cd·s/m2, as weaker stimuli than dark-adapted 0.01 ERG in the ISCEV standard protocol. These findings suggest that sildenafil triggers visual dysfunctions through PDE6 inhibition, and indicate that the multistep light stimulus method is highly sensitive for detection of phototransduction abnormalities in retinal rod cells.

Differential anti-Golgi complex autoantibody production following murine lactate dehydrogenase-elevating virus infection.

Lactate dehydrogenase-elevating virus (LDV) causes asymptomatic infection and persistent viremia in mice with unique infectious specificity directed to a certain subpopulation of macrophages leading to chronic infection and an immunological disorder that includes hyperimmunoglobulinemia and production of autoantibodies. Infection with a species of LDV originally isolated from mice carrying an LDV-contaminated transplantable tumor (LDV-W) was reported to induce anti-Golgi complex antibody (AGA) production. In contrast, infection with the most common LDV species (LDV-P) was not associated with AGA production. Here we performed the first independent side by side comparison of the effects of the two LDV strains on their hosts as an initial approach to investigating the production of AGA. After viral inoculation, both LDV-W and LDV-P infected mice exhibited similar changes in lactate dehydrogenase in plasma suggesting similar viral activity. However, AGA production was observed in only the LDV-W infected mice and these mice exhibited plasma IgG elevation and immune complex formation. These data validated the differential potential of LDV-W and LDV-P in the production of AGA. Future comparative characterizations in the immune processing of Golgi complex autoantigens using these viral strains may be useful in obtaining specific insights in the specific anti-Golgi complex autoimmune responses.