Suppression of ongoing experimental myasthenia by oral treatment with an acetylcholine receptor recombinant fragment.

Myasthenia gravis (MG) is an autoimmune disorder in which the nicotinic acetylcholine receptor (AChR) is the major autoantigen. In an attempt to develop an antigen-specific therapy for MG, we administered a nonmyasthenogenic recombinant fragment of AChR orally to rats. This fragment, corresponding to the extracellular domain of the human AChR alpha-subunit (Halpha1-205), protected rats from subsequently induced experimental autoimmune myasthenia gravis (EAMG) and suppressed ongoing EAMG when treatment was initiated during either the acute or chronic phases of disease. Prevention and suppression of EAMG were accompanied by a significant decrease in AChR-specific humoral and cellular responses. The underlying mechanism for the Halpha1-205-induced oral tolerance seems to be active suppression, mediated by a shift from a T-helper 1 (Th1) to a Th2/Th3 response. This shift was assessed by changes in the cytokine profile, a deviation of anti-AChR IgG isotypes from IgG2 to IgG1, and a suppressed AChR-specific delayed-type hypersensitivity response. Our results in experimental myasthenia suggest that oral administration of AChR-specific recombinant fragments may be considered for antigen-specific immunotherapy of myasthenia gravis.

Aseptic meningitis after embolization of cerebral aneurysms using hydrogel-coated coils: report of three cases.

SUMMARY: We report the development of aseptic meningitis in 3 patients with aneurysms treated with hydrogel-coated coils. Patients presented with febrile meningeal syndromes during the 24 hours following the procedures and responded to corticosteroids. One of them developed delayed hydrocephalus that required treatment with a ventriculoperitoneal shunt. Aseptic meningitis is one of the important complications related to hydrogel-coated coils that should be recognized. More information based on the posttreatment surveillance after use of hydrogel-coated coils is required.

NAMPT suppresses glucose deprivation-induced oxidative stress by increasing NADPH levels in breast cancer.

Nicotinamide phosphoribosyltransferase (NAMPT) is a rate-limiting enzyme involved in NAD+ biosynthesis. Although NAMPT has emerged as a critical regulator of metabolic stress, the underlying mechanisms by which it regulates metabolic stress in cancer cells have not been completely elucidated. In this study, we determined that breast cancer cells expressing a high level of NAMPT were resistant to cell death induced by glucose depletion. Furthermore, NAMPT inhibition suppressed tumor growth in vivo in a xenograft model. Under glucose deprivation conditions, NAMPT inhibition was found to increase the mitochondrial reactive oxygen species (ROS) level, leading to cell death. This cell death was rescued by treatment with antioxidants or NAD+. Finally, we showed that NAMPT increased the pool of NAD+ that could be converted to NADPH through the pentose phosphate pathway and inhibited the depletion of reduced glutathione under glucose deprivation. Collectively, our results suggest a novel mechanism by which tumor cells protect themselves against glucose deprivation-induced oxidative stress by utilizing NAMPT to maintain NADPH levels.

Suppression of experimental myasthenia gravis, a B cell-mediated autoimmune disease, by blockade of IL-18.

Interleukin-18 (IL-18) is a pleiotropic proinflammatory cytokine that plays an important role in interferon gamma (IFN-gamma) production and IL-12-driven Th1 phenotype polarization. Increased expression of IL-18 has been observed in several autoimmune diseases. In this study we have analyzed the role of IL-18 in an antibody-mediated autoimmune disease and elucidated the mechanisms involved in disease suppression mediated by blockade of IL-18, using experimental autoimmune myasthenia gravis (EAMG) as a model. EAMG is a T cell-regulated, antibody-mediated autoimmune disease in which the nicotinic acetylcholine receptor (AChR) is the major autoantigen. Th1- and Th2-type responses are both implicated in EAMG development. We show that treatment by anti-IL-18 during ongoing EAMG suppresses disease progression. The protective effect can be adoptively transferred to naive recipients and is mediated by increased levels of the immunosuppressive Th3-type cytokine TGF-beta and decreased AChR-specific Th1-type cellular responses. Suppression of EAMG is accompanied by down-regulation of the costimulatory factor CD40L and up-regulation of CTLA-4, a key negative immunomodulator. Our results suggest that IL-18 blockade may potentially be applied for immunointervention in myasthenia gravis.

Short peptides with induced beta-turn inhibit the interaction between HIV-1 gp120 and CD4.

To identify novel peptides that inhibit the interaction between human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein gp120 and CD4, we constructed a targeted phage-displayed peptide library in which phenylalanine and proline were fixed at the fourth and sixth positions, respectively, because Phe43 and the adjacent beta-turn of CD4 are critical for interaction with gp120. Two synthetic peptides were selected after three rounds of biopanning against gp120, and one of them, G1 peptide (ARQPSFDLQCGF), exhibited specific inhibition of the interaction between gp120 and CD4 with an IC(50) of about 50 microM. Structural analysis using NMR demonstrated that G1 peptide forms a compact cyclic structure similar to the CD4 region interacting with gp120. Two derivatives of G1 peptide, a linear hexameric peptide (G1-6) and a cyclic nonameric peptide (G1-c), were synthesized based on the structure of the G1 peptide. Interestingly, they showed higher inhibitory activities than did G1 peptide with IC(50)'s of 6 and 1 microM, respectively. Thus, this study might provide a new insight into the development of anti-HIV-1 inhibitors.

Mechanism of nasal tolerance induced by a recombinant fragment of acetylcholine receptor for treatment of experimental myasthenia gravis.

Acetylcholine receptor (AChR) is the major autoantigen in myasthenia gravis (MG) and experimental autoimmune MG (EAMG). Here we analyze the mechanisms involved in suppression of ongoing EAMG in rats by nasal administration of a recombinant fragment from the human AChR alpha-subunit. We demonstrate that such a fragment, expressed without a fusion partner, confers nasal tolerance that can be adoptively transferred. Our observations suggest that the underlying mechanism of this nasal tolerance is active suppression involving a shift from a Th1 to a Th2/Th3-regulated AChR-specific response which may be mediated by down regulation of costimulatory factors.

Induction of striatal neurogenesis enhances functional recovery in an adult animal model of neonatal hypoxic-ischemic brain injury.

While intraventricular administration of epidermal growth factor (EGF) expands the proliferation of neural stem/progenitor cells in the subventricular zone (SVZ), overexpression of brain-derived neurotrophic factor (BDNF) is particularly effective in enhancing striatal neurogenesis. We assessed the induction of striatal neurogenesis and consequent functional recovery after chronic infusion of BDNF and EGF in an adult animal model of neonatal hypoxic-ischemic (HI) brain injury. Permanent brain damage was induced in CD-1 (ICR) mice (P7) by applying the ligation of unilateral carotid artery and hypoxic condition. At 6 weeks of age, the mice were randomly assigned to groups receiving a continuous 2-week infusion of one of the following treatments into the ventricle: BDNF, EGF, BDNF/EGF, or phosphate buffered saline (PBS). Two weeks after treatment, immunohistochemical analysis revealed an increase in the number of BrdU(+) cells in the SVZ and striata of BDNF/EGF-treated mice. The number of new neurons co-stained with BrdU and betaIII-tubulin was also significantly increased in the neostriata of BDNF/EGF-treated mice, compared with PBS group. In addition, the newly generated cells were expressed as migrating neuroblasts labeled with PSA-NCAM or doublecortin in the SVZ and the ventricular side of neostriata. The new striatal neurons were also differentiated as mature neurons co-labeled with BrdU(+)/NeuN(+). When evaluated post-surgical 8 weeks, BDNF/EGF-treated mice exhibited significantly longer rotarod latencies at constant speed (48 rpm) and under accelerating condition (4-80 rpm), relative to PBS and untreated controls. In the forelimb-use asymmetry test, BDNF/EGF-treated mice showed significant improvement in the use of the contralateral forelimb. In contrast, this BDNF/EGF-associated functional recovery was abolished in mice receiving a co-infusion of 2% cytosine-b-d-arabinofuranoside (Ara-C), a mitotic inhibitor. Induction of striatal neurogenesis by the intraventricular administration of BDNF and EGF promoted functional recovery in an adult animal model of neonatal HI brain injury. The effect of Ara-C to completely block functional recovery indicates that the effect may be the result of newly generated neurons. Therefore, this treatment may offer a promising strategy for the restoration of motor function for adults with cerebral palsy (CP).

Endovascular coil embolization of 435 small asymptomatic unruptured intracranial aneurysms: procedural morbidity and patient outcome.

BACKGROUND AND PURPOSE: Whether treatment of small asymptomatic aneurysms is appropriate or not remains controversial. We performed a retrospective study on the procedural morbidity and mortality of coil embolization of small asymptomatic unruptured intracranial aneurysms (UIAs) to obtain a more generalized estimate of procedural risk. MATERIALS AND METHODS: A total of 435 small (maximum diameter < or = 7 mm) asymptomatic UIAs in 370 patients were treated by coil embolization. Aneurysm sizes were determined by using 3D angiograms. We assessed procedure-related morbidity and mortality, immediate postprocedural angiographic results, short-term imaging follow-up results, and clinical outcomes. RESULTS: Initial aneurysm occlusion was complete in 334 aneurysms, near complete in 78, and incomplete in 22. One internal carotid artery (ICA) aneurysm that ruptured during the procedure was treated with parent artery occlusion. Two hundred wide-neck aneurysms were coiled with the aid of various neck-remodeling techniques. The 44 procedure-related complications were the following: 24 thromboembolisms, 11 coil protrusions or prolapses into the parent vessel, 4 intraprocedural ruptures, 3 device-related complications, and 2 femoral-access complications. We had a total of 44 (10.1%) procedure-related complications with only 1 leading to persistent neurologic deficit. Procedure-related permanent morbidity and mortality were 0.27% (1/370) and 0%, respectively. CONCLUSIONS: In this series of small unruptured asymptomatic aneurysms, endovascular treatment was achieved with good short-term angiographic outcome and low permanent neurologic impairment. The goal of this study was not to provide a conclusion about treatment guidelines for small UIA but rather to help guide future recommendations by presenting a more generalized estimate of endovascular treatment risk than is currently available.

Role of tolerogen conformation in induction of oral tolerance in experimental autoimmune myasthenia gravis.

We recently demonstrated that oral or nasal administration of recombinant fragments of the acetylcholine receptor (AChR) prevents the induction of experimental autoimmune myasthenia gravis (EAMG) and suppresses ongoing EAMG in rats. We have now studied the role of spatial conformation of these recombinant fragments in determining their tolerogenicity. Two fragments corresponding to the extracellular domain of the human AChR alpha-subunit and differing in conformation were tested: Halpha1-205 expressed with no fusion partner and Halpha1-210 fused to thioredoxin (Trx), and designated Trx-Halpha1-210. The conformational similarity of the fragments to intact AChR was assessed by their reactivity with alpha-bungarotoxin and with anti-AChR mAbs, specific for conformation-dependent epitopes. Oral administration of the more native fragment, Trx-Halpha1-210, at the acute phase of disease led to exacerbation of EAMG, accompanied by an elevation of AChR-specific humoral and cellular reactivity, increased levels of Th1-type cytokines (IL-2, IL-12), decreased levels of Th2 (IL-10)- or Th3 (TGF-beta)-type cytokines, and higher expression of costimulatory factors (CD28, CTLA4, B7-1, B7-2, CD40L, and CD40). On the other hand, oral administration of the less native fragments Halpha1-205 or denatured Trx-Halpha1-210 suppressed ongoing EAMG and led to opposite changes in the immunological parameters. It thus seems that native conformation of AChR-derived fragments renders them immunogenic and immunopathogenic and therefore not suitable for treatment of myasthenia gravis. Conformation of tolerogens should therefore be given careful attention when considering oral tolerance for treatment of autoimmune diseases.

Modulation of aflatoxin B1 biotransformation by beta-naphthoflavone in isolated rabbit lung cells.

The cytotoxic and carcinogenic mycotoxin aflatoxin (AF) B1 (AFB1) is biotransformed by the cytochrome P450 monooxygenases (CYP) to a number of relatively nontoxic metabolites, as well as to the ultimate toxic metabolite, AFB1-8,9-epoxide. In a number of tissues and species, AFB1 hydroxylation to the relatively nontoxic metabolite, AFM1, is induced by beta-naphthoflavone (BNF) treatment. Although the liver is the principle target organ for AFB1 toxicity, the mycotoxin is also toxic and carcinogenic to respiratory tissues. To determine if BNF treatment alters the extent of pulmonary AFB1 bioactivation by enhancing detoxification and thereby decreasing epoxidation, the effects of BNF on pulmonary AFB1 metabolism were examined. Rabbit lung cells, isolated by protease digestion and centrifugal elutriation, were incubated with [3H]AFB1. In nonciliated bronchiolar epithelial (Clara) cell-enriched (45-50%) fractions, [3H]AFM1 production (pmol/mg DNA per 2 h) was increased by prior treatment of rabbits with BNF (80 mg/kg per day, 3 and 2 days before cell isolation) as follows: with 1.0 microM [3H]AFB1; control, 10.6 +/- 2.3; BNF, 30.0 +/- 6.4; with 0.10 microM [3H]AFB1; control, 9.4 +/- 4.7; BNF, 20.6 +/- 5.9. With 1.0 microM [3H]AFB1, prior treatment of animals with BNF abolished formation of [3H]aflatoxicol (AFL) but not [3H]AFQ1. The activation (epoxidation) of [3H]AFB1 was measured indirectly as covalent binding to endogenous DNA. With 1.0 microM [3H]AFB1, treatment of rabbits with BNF did not alter DNA binding (pmol/mg DNA per 2 h) in the Clara cell-enriched fraction: control, 103 +/- 41; BNF, 114 +/- 49. However, with 0.10 microM [3H]AFB1, DNA binding in the same fraction was 47% lower in cells from BNF treated animals: control, 17.4 +/- 4.2; BNF, 9.3 +/- 3.9. Formation of 8,9-dihydro-8,9-dihydroxy-AFB1, and the glutathione conjugate of the aflatoxin epoxide (AFB1-GSH) were not detectable at the AFB1 concentration and time point studied, in cells from either BNF-treated or control rabbits. Incubation of isolated, unseparated lung cells from untreated rabbits with 5.0 to 50 microM BNF decreased [3H]AFB1-DNA binding in the presence of 0.1 microM [3H]AFB1 by 35 to 77%, while lower BNF concentrations did not alter DNA binding. In lung cells isolated from BNF treated rabbits, BNF was not detectable (i.e. < 0.5 microM detection limit). Therefore, the amount of BNF present in isolated rabbit lung cells following in vivo treatment with BNF was below that required to directly inhibit AFB1-DNA adduct formation. The decrease in AFB1-DNA binding from rabbits treated with BNF is apparently due to the selective induction of CYP isozymes and related increases in AFM1 formation, and not to direct inhibition of epoxidation or enhanced conjugation of AFB1-8,9-epoxide with glutathione.

Prevention of passively transferred experimental autoimmune myasthenia gravis by a phage library-derived cyclic peptide.

Many pathogenic antibodies in myasthenia gravis (MG) and its animal model, experimental autoimmune MG (EAMG), are directed against the main immunogenic region (MIR) of the acetylcholine receptor (AcChoR). These antibodies are highly conformation dependent; hence, linear peptides derived from native receptor sequences are poor candidates for their immunoneutralization. We employed a phage-epitope library to identify peptide-mimotopes capable of preventing the pathogenicity of the anti-MIR mAb 198. We identified a 15-mer peptide (PMTLPENYFSERPYH) that binds specifically to mAb 198 and inhibits its binding to AcChoR. A 10-fold increase in the affinity of this peptide was achieved by incorporating flanking amino acid residues from the coat protein as present in the original phage library. This extended peptide (AEPMTLPENYFSERPYHPPPP) was constrained by the addition of cysteine residues on both ends of the peptide, thus generating a cyclic peptide that inhibited the binding of mAb 198 to AcChoR with a potency that is three orders of magnitude higher when compared with the parent library peptide. This cyclic peptide inhibited the in vitro binding of mAb 198 to AcChoR and prevented the antigenic modulation of AcChoR caused by mAb 198 in human muscle cell cultures. The cyclic peptide also reacted with several other anti-MIR mAbs and the sera of EAMG rats. In addition, this peptide blocked the ability of mAb 198 to passively transfer EAMG in rats. Further derivatization of the cyclic peptide may aid in the design of suitable synthetic mimotopes for modulation of MG.

Antigen-specific modulation of experimental myasthenia gravis: nasal tolerization with recombinant fragments of the human acetylcholine receptor alpha-subunit.

Myasthenia gravis (MG) and experimental autoimmune myasthenia gravis (EAMG) are antibody-mediated autoimmune diseases in which the nicotinic acetylcholine receptor (AcChoR) is the major autoantigen. The immune response in these diseases is heterogeneous and is directed to a wide variety of T and B cell epitopes of AcChoR. Candidate molecules for specific immunotherapy of MG should, therefore, have a broad specificity. We used recombinant fragments of the human AcChoR, encompassing the extracellular domain of the alpha-subunit, or shorter fragments derived from it, in experiments to modulate EAMG. We have demonstrated that intranasal administration of these recombinant fragments, which represent a major portion of epitopes involved in MG, prevents the induction of EAMG in rats and immunosuppresses an ongoing disease, as assessed by clinical symptoms, weight loss, and muscle AcChoR content. These effects on EAMG were accompanied by a marked reduction in the proliferative T-cell response and IL-2 production in response to AcChoR, in reduced anti-self AcChoR antibody titers and in an isotype switch of AcChoR-specific antibodies, from IgG2 to IgG1. We conclude that nasal tolerance induced by appropriate recombinant fragments of human AcChoR is effective in suppressing EAMG and might possibly be considered as a therapeutic modality for MG.

Blockade of CD40 ligand suppresses chronic experimental myasthenia gravis by down-regulation of Th1 differentiation and up-regulation of CTLA-4.

Myasthenia gravis (MG) and experimental autoimmune MG (EAMG) are T cell-dependent Ab-mediated autoimmune disorders, in which the nicotinic acetylcholine receptor (AChR) is the major autoantigen. Th1-type cells and costimulatory factors such as CD40 ligand (CD40L) contribute to disease pathogenesis by producing proinflammatory cytokines and by activating autoreactive B cells. In this study we demonstrate the capacity of CD40L blockade to modulate EAMG, and analyze the mechanism underlying this disease suppression. Anti-CD40L Abs given to rats at the chronic stage of EAMG suppress the clinical progression of the autoimmune process and lead to a decrease in the AChR-specific humoral response and delayed-type hypersensitivity. The cytokine profile of treated rats suggests that the underlying mechanism involves down-regulation of AChR-specific Th1-regulated responses with no significant effect on Th2- and Th3-regulated AChR-specific responses. EAMG suppression is also accompanied by a significant up-regulation of CTLA-4, whereas a series of costimulatory factors remain unchanged. Adoptive transfer of splenocytes from anti-CD40L-treated rats does not protect recipient rats against subsequently induced EAMG. Thus it seems that the suppressed progression of chronic EAMG by anti-CD40L treatment does not induce a switch from Th1 to Th2/Th3 regulation of the AChR-specific immune response and does not induce generation of regulatory cells. The ability of anti-CD40L treatment to suppress ongoing chronic EAMG suggests that blockade of CD40L may serve as a potential approach for the immunotherapy of MG and other Ab-mediated autoimmune diseases.

Sclerosing meningioma: immunohistochemical analysis of five cases.

Sclerosing meningioma is a rare morphologic subtype of meningioma and may be mistaken for atypical or malignant meningioma and astrocytoma or schwannoma because of marked collagen deposits and a sparse population of cells with little resemblance to meningothelial cells. Authors describe the histopathologic and immunophenotypic features of five cases of sclerosing meningioma. Histologically, all the cases consisted of paucicellular collagenous tissue containing spindle cells with or without small foci of meningothelial cell proliferation. The morphology and immunohistochemical profile of the spindle cells were different from those of conventional meningothelial cells. The meningothelial cells showed a typical immunoreactivity of conventional meningiomas, while the spindle cells displayed a strong expression of vimentin. The Ki-67 labelling index was uniformly low in all cases, and none of cases expressed p53 protein. In summary, the recognition of meningothelial cells in massively sclerotic lesions is helpful for a correct diagnosis. In the cases with a total absence of meningothelial cells, however, the vague collagenous whorls are more diagnostic rather than immunohistochemistry. Considering association with clear cell meningioma, prospective and retrospective long-term follow-up is necessary for deciding whether reminiscent clear cell meningiomas should be separated from sclerosing meningioma or not.

Perfluorinated compounds in coastal waters of Hong Kong, South China, and Korea.

Perfluorinated compounds (PFCs), such as perfluorooctanesulfonate (PFOS) and related compounds, have recently been identified in the environment. PFOS, the terminal degradation product of many of the PFCs, has been found globally in many wildlife species, as well as open ocean waters, even in remote regions far from sources. In this study, a solid-phase extraction procedure coupled with high-performance liquid chromatography interfaced to high-resolution mass spectrometry was used to isolate, identify, and quantify small concentrations of PFCs in seawater. These techniques were applied to investigate the local sources of PFCs in several industrialized areas of Asia and provide information on how the PFCs are circulated by coastal currents. Ranges of concentrations of PFOS in coastal seawaters of Hong Kong, the Pearl River Delta, including the South China Sea, and Korea were 0.09-3.1, 0.02-12, and 0.04-730 pg/mL, respectively, while those of perfluorooctanoic acid (PFOA) were 0.73-5.5, 0.24-16, and 0.24-320 pg/mL, respectively. Potential sources of PFCs include major industrialized areas along the Pearl River Delta of southern China and major cities of Korea, which are several of the fastest growing industrial and economic regions in the world. Detectable concentrations of PFOS and PFOA in waters of southern China were similar to those in the coastal marine environment of Japan and certain regions in Korea. Concentrations of PFCs in several locations in Korean waters were 10-100-fold greater than those in the other locations on which we report here. The spatial and seasonal variations in PFC concentrations in surface seawaters in the Pearl River Delta and South China Sea indicate the strong influence of the Pearl River discharge on the magnitude and extent of PFC contamination in southern China. All of the concentrations of PFOS were less than those that would be expected to cause adverse effects to aquatic organisms or their predators except for one location in Korea adjacent to an industrialized area. Hazard quotients were from <0.001 to 0.002 for aquatic animals and ranged from <0.001 to 17 for predatory birds.

Childhood meningioma: unusual location, atypical radiological findings, and favorable treatment outcome.

OBJECTS: To investigate the characteristics of childhood meningioma, especially, locations, radiological findings, pathological features (including proliferative potential) and outcome, 11 children with meningiomas were retrospectively analyzed. RESULTS: Unusual location, large size, frequent calcification, and cyst formation were characteristic radiological findings. Gross total resection was achieved in 8 patients, and there was recurrence in 2. Gamma knife radiosurgery was performed on residual and recurrent tumors. MIB-1 indices tended to be high in large tumors. Nine patients had a Karnofsky Performance Scale of more than 70 during the follow-up period of 10 months to 19.5 years. Surgical treatment rendered 4 of 5 epileptic patients seizure free. The childhood meningiomas examined had unusual locations, atypical radiological findings, and various proliferative potentials. CONCLUSIONS: Complete resection is the treatment of choice. Gamma knife radiosurgery can be a good alternative for residual tumors and small recurrent tumors. The outcome of childhood meningiomas is good after surgery.