Bibliothek

Notizen: A probe wave system was constructed for studying the excitation of the Alfvén ion cyclotron (AIC) modes in the anchor cell of the GAMMA 10 tandem mirror. In the central cell, the AIC modes are spontaneously excited as axial eigenmodes due to the strong temperature anisotropy. In the anchor cell, the AIC modes were not observed though the anisotropy is the same as in the central cell. The axial profiles of the magnetic field strength and plasma parameters in the anchor cell are different from those in the central cell. Eigenmodes are excited externally in the AIC frequency range by injecting probe waves. This suggests the AIC modes are unstable in the anchor cell and grow to the detectable level when boundary conditions are realized. © 2001 American Institute of Physics.

Notizen: A high precision atomic polarimeter system for the use in beam-foil spectroscopy experiments with a few keV/amu heavy-ion beams has been developed. The polarimeter measures the circular polarization of fluorescences from the beam ion in-flight after the beam–foil interaction. The present system has two identical such polarimeters in both sides of the beam axis to reduce the systematic errors such due to the fluctuations of beam current, background and so on. A successful use of an ultrathin carbon foil (1.5 μg/cm2), which was durable for several hours against a few hundred nA beam irradiation, enabled the beam–foil experiments with such low energy heavy-ion beams. A performance test of the polarimeter system was carried out in the tilted foil experiments with a 1.7 keV/amu 14N+ beam. The atomic polarization was observed for the transition 1s22s22p3p 1D→1s22s22p3p 1P, whose fluorescence wavelength is 399.5 nm, in the N+ ion (N II). The polarization was approximately −2% for the tilt angle of −40° and showed monotone increasing with increasing tilt angle up to +2% for +40°. The polarization at 0° was (0.002±0.25)%, which is highly consistent with the expected polarization of 0%. This result indicates the high reliability of the present polarimeter system. This is the first tilted-foil experiment at such low beam energy. The present experimental technique will be very useful for studies of the polarization mechanism of the beam–foil interaction. © 2000 American Institute of Physics.

Notizen: In the GAMMA10 tandem mirror, a strong ion cyclotron range of frequency heating is performed. As a result of the heating, the Alfvén ion cyclotron (AIC) modes are spontaneously excited due to the strong temperature anisotropy. The AIC modes in the GAMMA10 are excited as the axial eigenmodes and detected at the whole of the device. In the recent experiments, the clear standing wave structure is observed with the magnetic probe measurements. Characteristics of the AIC modes and the measurement of the axial profile are presented. © 2001 American Institute of Physics.

Notizen: A pressure driven m=1/n=1 mode is excited by lower hybrid current drive in the WT-3 tokamak [T. Maehara et al., Nucl. Fusion 38, 39 (1998)]. The excitation of the mode is accompanied with the decrease of the magnetic shear and with the peaking of the soft x-ray emissivity profile inside the q=1 surface. The crescent-shaped mode structure appeared on the contour map of the soft x-ray emissivity is consistent with that of the quasi-interchange mode. The m=1 mode can be suppressed by electron cyclotron heating near the q=1 surface. The range of the location of the electron cyclotron resonance layer effective for the complete suppression is much wider and the time scale for the suppression is much faster than those in the case of the suppression of the tearing mode in the ohmic heating plasma. © 2000 American Institute of Physics.

Notizen: Ion distributions in a loss cone are measured in the GAMMA 10 tandem mirror [Phys. Rev. Lett. 55, 939 (1985)]. When Alfvén ion cyclotron (AIC) modes are excited in the central cell, enhanced end-loss of ions is observed for a characteristic energy region which agrees well with the resonant ion cyclotron condition with the AIC wave. From measurements of pitch angle distributions of end-loss ions, it is found that the loss cone is filled for this characteristic energy region, indicating an ion diffusion in a velocity space induced by the AIC wave. Magnitude of the observed additional end-loss increases with increase in the amplitude of the AIC modes. In the present experimental parameters in GAMMA 10, the AIC wave effect on the axial ion confinement is not serious. © 2000 American Institute of Physics.

Notizen: Summary Background Neurogenic components, such as neurotrophic factors and neuropeptides, are probably involved in the pathogenesis of atopic dermatitis (AD) via the neuroimmunocutaneous system. Numerous in vitro and in vivo studies have shown that nerve growth factor (NGF), the best-characterized member of the neurotrophin family, modulates the synthesis of the neuropeptide substance P (SP), both of which may be associated with the pathogenesis of human allergic diseases. Objectives To evaluate the levels of NGF and SP in the plasma of patients with AD and to examine their possible correlation with disease activity. Methods We measured plasma levels of NGF by an immunoenzymatic assay and of SP by aradioimmunoassay in 52 patients with AD, and compared them with 35 normal non-atopic controls. The severity of the disease in AD patients was evaluated using validated clinical scoring systems. Results Patients with AD had significant increases in plasma levels of NGF and SP compared with controls (P 〈 0·0005 and P 〈 0·0001, respectively). A positive correlation between the plasma levels of NGF and SP was found in AD patients (correlation coefficient, Cc = 0·920, P 〈 0·0001). There was a significant correlation of plasma NGF and SP levels with disease activity evaluated using three different scoring systems: the grading system of Rajka and Langeland (P 〈 0·001 and P 〈 0·01, respectively), the objective Severity Scoring of AD (Cc = 0·656, P 〈 0·005 and Cc = 0·752, P 〈 0·0005, respectively) and the Eczema Area and Severity Index (Cc = 0·740, P 〈 0·001 and Cc = 0·765, P 〈 0·005, respectively). Conclusions These data represent the first reported evidence of increased plasma levels of NGF and SP in an allergic human skin disease. They suggest that these neurogenic factors systemically modulate the allergic response in AD, probably through interactions with cells of the immune-inflammatory component. In addition, NGF and SP may be useful markers of disease activity in patients with AD.

Notizen: Background : Omeprazole 10 mg is used as maintenance therapy for gastro-oesophageal reflux disease, but previous reports have not mentioned the potency of its acid suppression.Aim : To evaluate the potency of acid suppression with omeprazole 10 mg, in relation to CYP2C19 genotypes.Methods : Eighteen healthy subjects without Helicobacter pylori participated. After a 7-day regimen of omeprazole 10 mg, 20 mg, lafutidine 20 mg (a novel H2-receptor antagonist) or water only (baseline data), intragastric pH was measured for 24 h.Results : With omeprazole 10 mg, greater differences were observed than 20 mg in median pH values and pH 〉 4 holding time ratios between poor metabolizers (PMs, n = 6) and the others [homozygous extensive metabolizers (homo-EMs, n = 6) and heterozygous extensive metabolizers (hetero-EMs, n = 6)]. With lafutidine 20 mg, these parameters were not influenced by the genotype. The potency of acid suppression was: omeprazole 20 mg ≈ lafutidine 20 mg 〉 omeprazole 10 mg in homo-EMs, omeprazole 20 mg 〉 omeprazole 10 mg ≈ lafutidine 20 mg in hetero-EMs, and omeprazole 20 mg ≈ omeprazole 10 mg 〉 lafutidine 20 mg in PMs.Conclusions : Omeprazole 10 mg strongly suppresses acid secretion, but depending on the CYP2C19 genotypes shows greater interindividual variations in suppression than 20 mg.

Notizen: Background  Although some patients with psoriasis vulgaris also complain of severe pruritus, the data available regarding pruritus in psoriasis are sparse.Objectives  To clarify the mechanism and mediators involved in the pruritus of psoriasis vulgaris, we compared itch-associated factors in lesional skin from psoriatic patients vs. skin without pruritus quantitatively using a panel of histological and immunohistological parameters.Patients and methods  Biopsied specimens were obtained from 38 patients with psoriasis vulgaris who were divided into two groups according to the presence or absence of pruritus.Results  When compared with psoriatic patients devoid of pruritus, lesional skin from patients with pruritus showed the following characteristic features: (i) a rich innervation both in the epidermis and in the papillary dermis; (ii) an increase in neuropeptide substance P-containing nerve fibres in perivascular areas; (iii) decreased expression of neutral endopeptidase in the epidermal basal layer as well as in the endothelia of blood vessels; (iv) many mast cells showing degranulating processes in the papillary dermis; (v) a strong immunoreactivity for nerve growth factor (NGF) throughout the entire epidermis and an increased NGF content in lesional skin homogenates; (vi) an increase in the expression of high-affinity receptors for NGF (Trk A) in basal keratinocytes and in dermal nerves; (vii) an increased population of interleukin-2-immunoreactive lymphocytes; and (viii) a strong expression of E-selectin on vascular endothelial cells. A significant correlation was observed between the severity of pruritus and protein gene product 9.5-immunoreactive intraepidermal nerve fibres, NGF-immunoreactive keratinocytes, expression of Trk A in the epidermis and the density of immunoreactive vessels for E-selectin. These findings indicate that possible pruritogenic mediators in psoriatic lesional skin are neurogenic factors including innervation, neuropeptide substance P, neuropeptide-degrading enzymes and NGF, activated mast cells, one or more cytokines and endothelial–leucocyte adhesion molecules.Conclusions  These data document for the first time itch-related local markers in psoriasis, and suggest complex and multifactorial mechanisms of pruritus in the disease. These results provide the groundwork for further studies to evaluate the efficacy of antipruritic treatment for psoriatic patients.

Notizen: Background : Our recent histochemical studies have revealed an increase in myofibroblasts and in leptin and its receptor in endothelial cells, and myofibroblasts in Helicobacter pylori-infected human and Mongolian gerbil fundic mucosa.Aim : The present study was undertaken to clarify the H. pylori–induced interaction between leptin in cultured gastric surface mucous cells and fibroblasts.Methods : GSM06 cells were incubated with an air− liquid interface on a collagen gel layer containing mouse fibroblast cell line L929. Medium containing H. pylori bacilli (ATCC43504) at 10–100 times higher concentration than the GSM06 cells was added from the luminal side and the localization of leptin was observed by immunohistochemistry. The transformation of L929 cells to myofibroblasts was detected by electron microscopy and PR 2D3 immunoreactivity.Results : L929 cells in the control group showed a spindle shape with scarce cytoplasm. In the H. pylori-treated group, L929 cells showed features characteristic of myofibroblasts, and most GSM06 and L929 cells showed leptin immunoreactivity. In contrast, L929 cells incubated with H. pylori alone did not undergo this differentiation.Conclusions : Attachment of H. pylori to surface epithelial cells caused conversion of fibroblasts to myofibroblasts. We suggest that leptin plays a role in this transformation.

Notizen: Background : Rebamipide is a gastroprotective agent to stimulate prostaglandin generation in gastric mucosa and attenuate the activity of neutrophils, but direct evidence for the effector sites of this agent has remained to be clarified.Aim : The present study was undertaken to show the effector sites of rebamipide in control and ulcer-provoked rats.Methods : The rats were divided into control, acetic acid- and ethanol-treated rats. In the acetic acid-treated group, 100% acetic acid was attached to the serosal surface of the stomach for 30 s, 7 days before the experiments. In the ethanol-treated group, a dose of 0.5 mL/100 g body weight of 50% ethanol was administered through orogastric intubation 2 h before the experiments. Using the unfixed cryostat sections, aqueous solution of 3H-rebamipide was applied and the localization of the binding sites of rebamipide was investigated by autoradiography.Results : In the control rats, rebamipide was found to bind to the surface epithelial cells. In the ethanol-treated group, few binding sites were observed in the damaged gastric mucosa. In the acetic acid-treated group, the marked accumulation of the binding sites of 3H-rebamipide was observed in the mesenchymal cells in the lamina propria mucosae between the regenerated gastric epithelial cells. Combination of autoradiography and immunohistochemistry has revealed that iNOS-immunoreactive cells had the strong binding of rebamipide in the acetic acid-treated group. Some of these cells were CD68-positive macrophages, while others were CD68-negative, corresponding to polymorphonuclear leucocytes. In the ethanol-treated acute gastric mucosal injury group, few binding sites were observed in the damaged gastric mucosa.Conclusions : Autoradiography has made it clear that rebamipide binds to iNOS-positive cells in the gastric mucosa 7 days after acetic acid-treatment.