Ghrelin Induces Fasted Motor Activity of the Gastrointestinal Tract in Conscious Fed Rats

Ghrelin is a newly discovered orexigenic peptide originating from the stomach. However, its action in regulating the fed and fasted motor activity of the digestive tract is not fully understood. In the present study, we examined the effects of intracerebroventricular ( i.c.v. ) and intravenous ( i.v. ) injection of ghrelin on the physiological fed and fasted motor activities in the stomach and duodenum of freely moving conscious rats. i.c.v. and i.v. injection of ghrelin induced fasted motor activity in the duodenum in normal fed rats, while i.v. injection of ghrelin induced fasted motor activity in both the stomach and duodenum in vagotomized rats. The effects of i.c.v. and i.v. injected ghrelin were blocked by growth hormone secretagogue receptor (GHS-R) antagonist given by the same route and also blocked by immunoneutralization of neuropeptide Y (NPY) in the brain. The effects of i.v. injected ghrelin were not altered by i.c.v. injection of GHS-R antagonist in vagotomized rats. Injection of GHS-R antagonist blocked the fasted motor activity in both the stomach and duodenum in vagotomized rats but did not affect the fasted motor activity in normal rats. Low intragastric pH inhibited the effect of ghrelin. The present results indicate that ghrelin is involved in regulation of fasted motor activity in the stomach and duodenum. Peripheral ghrelin may induce the fasted motor activity by activating the NPY neurons in the brain, probably through ghrelin receptors on vagal afferent neurons. Once the brain mechanism is eliminated by truncal vagotomy, ghrelin might be primarily involved in the regulation of fasted motor activity through ghrelin receptors on the stomach and duodenum. The action of ghrelin to induce fasted motor activity is strongly affected by intragastric pH; low pH inhibits the action.     

Ultrastructural localization of laminin-5 (gamma2 chain) in the rat peri-implant oral mucosa around a titanium-dental implant by immuno-electron microscopy

Laminin-5 (Ln-5) is an important molecule associated with epithelial cell adhesion and migration. In the gingiva around the tooth, Ln-5 localizes within basement membranes between the junctional epithelium (JE) and the tooth or connective tissue. Recently, we reported that in the oral mucosa around a dental implant, Ln-5 is expressed within the basement membranes at the implant-peri-implant epithelium (PIE) interface, and at the PIE-connective tissue interface. However, the ultrastructural localization of Ln-5 within or along the PIE has not yet been reported. Therefore, peri-implant oral mucosa was treated with anti-Ln-5 (gamma2 chain) antibody and examined using immuno-electron microscopy. Ln-5 was localized in the cells of the innermost-third layer and basal layer of the PIE. A 100-nm-wide Ln-5-positive internal basal lamina (basement membrane) and hemidesmosomes as adhesion structures were formed at the apical portion of the implant-PIE interface. However, at the upper-middle portion of the interface, these adhesion structures were not observed. Furthermore, at the PIE-connective tissue interface, the Ln-5-positive external basal lamina (basement membrane) and hemidesmosomes were partially deficient. Judging from these findings, we concluded that Ln-5 contributes to the attachment of the PIE to the titanium surface, and that PIE attached to titanium at the apical portion of the dental implant-PIE interface.     

Phase stability after aging and its influence on pin-on-disk wear properties of Ce-TZP/Al2O3 nanocomposite and conventional Y-TZP

Recently zirconia/alumina composites have been examined by many researchers as the new generation of bearing materials in total joint replacements. In this study, the phase stability of a Ce-TZP/Al(2)O(3) nanocomposite and conventional Y-TZP after aging, and its influence on wear resistance, were investigated. Very slight phase transformation was observed in both types of ceramics 18 months after the implantation of Ce-TZP/Al(2)O(3) or Y-TZP samples into rabbit tibiae. However, Y-TZP showed marked phase transformation (approximately 80%) after aging in an autoclave (121 degrees C) for 190 h or in physiological saline at 62 degrees C for 18 months, whereas the new composite remained almost resistant to degradation. According to the results of self-pairing pin-on-disk wear tests using ceramic specimens with or without autoclave aging, the wear factor was almost the same between Ce-TZP/Al(2)O(3) samples with and without aging (6.74 +/- 0.36 x 10(-8) and 6.04 +/- 0.95 x 10(-8) mm(3)/Nm, respectively). In contrast, although non-aged Y-TZP had the lowest wear factor (4.88 +/- 0.51 x 10(-8) mm(3)/Nm) of all specimens tested, aged Y-TZP showed 10-fold greater wear than nonaged Y-TZP. The present study suggests that Ce-TZP/Al(2)O(3) nanocomposite has much greater phase stability than Y-TZP, and that its wear properties are not influenced by aging.     

Differential contribution of the FcRγ chain to the surface expression of the T cell receptor among T cells localized in epithelia: analysis of FcRγ-deficient mice

The function of the Fc receptors γ chain (FcR_γ) for the expression of the T cell receptor (TCR) complex and for T cell development, especially for T cells localized in epithelia, was investigated by analyzing FcR_γ-deficient mice. In wildtype mice, CD8αα⁺β^?TCRαβ⁺ T cells of intestinal intraepithelial lymphocytes (i-IEL) utilized CD3ζ homodimers and ζ-FcR_γ heterodimers, whereas CD8α α⁺β^?TCR_γδ⁺ i-IEL used ζ-FcR_γ and FcR_γ homodimers in the TCR complex. On the other hand, these T cells in FcR_γ-deficient mice contained only ζ homodimers. The surface expression of the TCR complex was reduced in CD8αα⁺β^?i-IEL and dendritic epidermal T cells (DETC) in these mice, whereas the development of these T cells was normal. The degree of reduction appeared to depend on the expression level of FcR_γ. In contrast to these populations, TCR_γδ⁺ intraepithelial T cells in reproductive organs (r-IEL) were dramatically decreased, suggesting that the development of r-IEL is FcR_γ-dependent, probably due to the predominant usage of FcR_γ homodimers in the TCR complex. These results indicate that the FcR_γ chain contributes differently to the TCR expression and to the development of T cells localized in epithelia.     

Appearance of high-frequency alpha band with disappearance of low-frequency alpha band in EEG is produced during voluntary abdominal breathing in an eyes-closed condition

This study examined the effects of voluntary abdominal breathing (VAB) on the electroencephalogram (EEG) in 22 healthy subjects. VAB was characterized by prolonged rhythmic contraction of abdominal muscles for 20 min in an eyes-closed condition. The breathing rate was instructed to be very slow, i.e., 3-4 breaths/min (inspiratory time for 6-8s and expiratory time for 9-12s). A low-frequency alpha band appeared immediately after eye closing, but it later disappeared and was replaced by a new development of a high-frequency alpha band 4-5 min after the onset of VAB. The subjects had a feeling of vigor-activity with a tendency of reduced anxiety during and/or after VAB, as assessed by POMS and STAI questionnaire scores. On the other hand, during resting in the eye-closed condition, the disappearance of the low-frequency alpha band was replaced by the occurrence of a theta/delta band. The subjects became drowsy in this condition. We therefore conclude that the increase in high-frequency alpha activity is linked to the state of vigor-activity with a tendency of reduced anxiety. Since the urinary serotonergic level significantly increased after the VAB, we suggest that the serotonergic neurons within the brain may produce the changes in the EEG patterns.     

Establishment and characterization of cell line TNMY1 derived from human malignant fibrous histiocytoma

Although malignant fibrous histiocytoma (MFH) is one of the most common soft tissue sarcomas, its pathogenesis remains unclear. In this study, a cell line derived from human MFH, TNMY1, was established from a metastatic chest-wall lesion of a 60-year-old woman with MFH. The TNMY1 cell line was passaged 95 times, and it still retained the biological characteristics of the original tumor. TNMY1 consists of spindle-shaped cells and pleomorphic cells associated with multinucleated giant cells. Immunohistochemical studies showed that the spindle-shaped and pleomorphic cells were positive for vimentin, CD68 and alpha-smooth muscle actin, but negative for epithelial membrane antigen, desmin, muscle actin, alpha-sarcomeric actin, myoglobin, lysozyme and S-100 protein. The cells expressed collagen types I, III and V. These results indicate that MFH may originate from mesenchymal stem cells with the potential to differentiate into either fibroblasts or histiocytes. An elevated level of collagen type V mRNA expression is considered to support a diagnosis of MFH.     

Histologic transformation in extranodal non-Hodgkin's lymphoma

Histologic transformation in the course of non-Hodgkin's lymphoma (NHL) has been reported to occur in 18 to 30% of the cases. Less favorable prognosis in cases with initial low grade malignancy followed by emergence of high grade malignancy has been previously described. In the previous literature, the histologic transformation has been examined mostly in nodal NHL. In the present study, histologic transformation in the course was investigated on 20 cases with early extranodal NHL. All these 20 cases were diffuse lymphomas, and were composed of 7 cases with low grade malignancy and 13 cases with high grade malignancy. Histologic transformation was not observed in any of these cases. These findings indicate that the frequency of histologic transformation is much lower in extranodal NHL than in nodal NHL. The prognostic significance of these findings is also discussed.     

Idiopathic right ventricular dilation. Special reference to "arrhythmogenic right ventricular dysplasia" and analogous lesions

Two autopsy cases which showed marked depletion of the right ventricular musculature of the heart accompanied with marked infiltration of the adipose tissue were reported. The first cases was an 18-year-old female who died of right sided congestive heart failure after about 4-years clinical course. The autopsy disclosed marked dilation of the right atrium and ventricle. The entire free wall of the right ventricle was markedly thin. Microscopically, most of the myocardial fibers of the right ventricle were replaced by fat and fibrous tissue. The second case, a 15-year-old boy, whose identical twin was previously diagnosed as arrhythmogenic right ventricular dysplasia designated by Fontaine et al., died suddenly during exercise. He showed no cardiac symptoms but electrocardiogram was abnormal. Autopsy revealed majority of the myocardial fibers of the right ventricular free wall were replaced by fatty tissue. In both cases, fatty infiltration was mainly noticed at the epicardial side and some myocardial fibers remained in the fatty tissue showed hypertrophic and/or degenerative changes. Review of the literature on similar cases showing depletion of the right ventricular musculature including so-called adult's Uhl anomaly, ARVD and dilated right ventricular myocardiopathy was conducted and the relationship of the present cases with these lesions was discussed.