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.     

Association of HLA alleles with response (especially biochemical response) to interferon therapy in Japanese patients with chronic hepatitis C.

The response of chronic hepatitis C to interferon (IFN) treatment is classified as complete response (CR), biochemical response (BR), or no response (NR). Several studies have found no difference in prevention of hepatocellular carcinoma by IFN therapy between patients with CR and those with BR. We investigated whether specific human leukocyte antigen (HLA) alleles were associated with response to IFN, especially BR, in 138 patients with chronic hepatitis C. Comparing patients with and without CR, male, a low viral titer, genotype 2a or 2b, HLA-B55, and HLA-DRB1-0803 were more common in the group with CR. Multivariate analysis showed that age (adjusted odds ratio [OR], 0.95 by every year [95% confidence interval [CI] 0.90 - 0.99], p = 0.028), genotype 2a or 2b (5.21 [95% CI 1.63 - 16.6], p = 0.005), and low viral titer (8.58 (2.66 - 27.7), p < 0.001) were associated with CR. Comparing patients with BR and NR, the pretreatment alanine aminotransferase (ALT) level was lower in the BR group (p < 0.001). Both HLA-B7 and HLA-DRB1-0101 were more common in this group (p = 0.002). As the alleles HLA-B7 and HLA-DRB1-0101 were in linkage disequilibrium, the HLA-B7-DRB1-0101 haplotype may be associated with BR. Multivariate analysis indicated that a low ALT level (0.98 by every 1 IU/L [95% CI 0.98 - 0.99], p = 0.001) and HLA-B7-DRB1-0101 haplotype (32.3 [95% CI 1.50 - 693.1], p = 0.026) contributed significantly to BR. This study suggested that host HLA expression, but not viral factors, can influence BR.     

Cell-type-specific excitatory and inhibitory circuits involving primary afferents in the substantia gelatinosa of the rat spinal dorsal horn in vitro

The substantia gelatinosa (SG) of the spinal dorsal horn shows significant morphological heterogeneity and receives primary afferent input predominantly from Aδ- and C-fibres. Despite numerous anatomical and physiological studies, correlation between morphology and functional connectivity, particularly in terms of inhibitory inputs, remains elusive. To compare excitatory and inhibitory synaptic inputs on individual SG neurones with morphology, we performed whole-cell recordings with Neurobiotin-filled-pipettes in horizontal slices from adult rat spinal cord with attached dorsal roots. Based on dendritic arborization patterns, four major cell types were confirmed: islet, central, radial and vertical cells. Dorsal root stimulation revealed that each class was associated with characteristic synaptic inputs. Islet and central cells had monosynaptic excitatory inputs exclusively from C-afferents. Islet cells received primary-afferent-evoked inhibitory inputs only from Aδ-fibres, while those of central cells were mediated by both Aδ- and C-fibres. In contrast, radial and vertical cells had monosynaptic excitatory inputs from both Aδ- and C-fibres and inhibitory inputs mediated by both fibre types. We further characterized the neurochemical nature of these inhibitory synaptic inputs. The majority of islet, central and vertical cells exhibited GABAergic inhibitory inputs, while almost all radial cells also possessed glycinergic inputs. The present study demonstrates that SG neurones have distinct patterns of excitatory and inhibitory inputs that are related to their morphology. The neurotransmitters responsible for inhibitory inputs to individual SG neurones are also characteristic for different morphological classes. These results make it possible to identify primary afferent circuits associated with particular types of SG neurone.     

Auto-MHC class II-reactive T cell line obtained from MRL/+ mice suffering from lpr-GVHD. II. Analyses of functional characteristics of T cell line by in vivo administration.

Functional characteristics of an autoreactive (I-Ek-restricted) T cell line (l/+ T1), previously established from MRL/M(p-)+/+(MRL/+) mice with lpr-GVHD, were analyzed in vivo. Intravenous injection of l/+ T1 cells to non-irradiated H-2k (MRL/+ or AKR) mice (but not H-2d mice) induced enhanced spontaneous proliferation of recipient spleen cells; this was also I-Ek self-restricted. This augmented self-reactivity seemed to be mediated by recipient L3T4+ T cells, since few l/+ T1 cells were detected in the spleen cells of l/+ T1-injected AKR mice by cell surface marker analyses, and the treatment of the spleen cells with anti-Thy-1.1 antibody (Ab) or anti-L3T4 Ab plus complement abolished this enhanced spontaneous proliferation. The production of IgM rheumatoid factor (RF) in AKR mice and IgG RF in MRL/+ mice increased, although no enhancement of anti-ssDNA Ab production was observed. Judging from both spleen B cell proportion and serum Ig levels, autoantibody induction by the injection of l/+ T1 cells was not associated with polyclonal B cell activation. When lethally irradiated B10 congenic mice were used as recipients, B10. BR mice showed elevated levels of IgM anti-ssDNA and IgM RF 1 wk after l/+ T1 cell injection; it is likely that lethal irradiation causes autoantigens, particularly DNA, to be exposed. These findings suggest that the autoreactivity of l/+ T1 cells can be transferred to recipient L3T4+ T cells via T-T interaction or the immunological network, and that increased autoreactivity induces autoantibody production in the presence of autoantigen stimulation. In contrast to the stimulatory effects observed in AKR and MRL/+ mice, MRL/Mp-lpr/lpr(MRL/lpr) mice showed a different response to the injection of l/+ T1 cells; spontaneous proliferation of spleen cells and autoantibody production were not enhanced, and suppression of the mitogen responses was observed. It is discussed that lpr-GVHD may be due to these unusual features of MRL/lpr mice.     

TAC-101, a benzoic acid derivative, inhibits liver metastasis of human gastrointestinal cancer and prolongs the life-span

We examined the anti-tumor effect of a novel benzoic acid derivative, TAC-101 (4-[3,5-bis(trimethylsilyl) benzamide] benzoic acid) on models with liver metastasis. Oral administration of TAC-101 significantly inhibited spontaneous liver metastasis of AZ-521 (human gastric cancer ) by orthotopic implan-tation to athymic nude mice. It also inhibited both the liver metastasis of AZ-521 induced by intrasplenic injection and the secondary lung metastasis from the liver. In addition, TAC-101 inhibited the proliferation of Co-3 (human colon adenocarcinoma) that formed a single nodule in the liver of athymic nude mice by intrahepatic implantation. The growth inhibitory effect of TAC-101 on AZ-521 experimental liver metastasis was observed when treatment was started on day 7, 14, or 21 which may correspond to the progressive stage of liver metastasis in clinical settings. Multiple administration of TAC-101 (8 mg/kg/day) significantly prolonged survival time of the animals with liver met astasis by intrasplenic injection of AZ-521 (T/C = 230%) and A549 (human lung adenocarcinoma; T/C = 186%). These effects of TAC-101 were stronger than those of 5-FU, CDDP or ATRA. Furthermore, TAC-101 inhibited the binding of AP-1 to DNA on electrophoretic mobility shift assay using nuclear extract of AZ-521 cells, although ATRA did not inhibit. These findings suggested that TAC-101 may be a candidate for a new class of anti-cancer agents for liver metastasis. © Rapid Science Ltd.     

Thermodynamic studies on poly(a) · poly(u) duplex-dye systems

The interaction between poly(A) · poly(U) duplex and dyes (proflavine (PF) and 9-aminoacridine (9-AA)) was studied by means of the heat of mixing. From the results, thermodynamic quantities of poly(A) · poly(U) duplex-dye systems for the intercalation process were estimated. The free energy change for the poly(A) · poly(U) duplex-(PF) system is smaller than that for the poly(A) · poly(U) duplex-(9-AA) system, indicating that PF intercalated into poly(A) · poly(U) duplex is more stable than the intercalated 9-AA. This conclusion is based on the absolute value of the heat of interaction between PF and poly(A) · poly(U) duplex being larger than that between 9-AA and the poly(A) · poly(U) duplex.     

Direct measurement of phagosomal reactive oxygen by luminol-binding microspheres

A new method, utilizing microsphere-bound luminol, which makes possible the direct measurement of highly reactive oxygen within phagosomes, was studied. When Freund's complete adjuvant-elicited mouse peritoneal macrophages and luminol-binding microspheres were mixed, the microspheres were engulfed in macrophages and enclosed in phagosomes, where chemiluminescence (CL) was generated, showing the generation of highly reactive oxygen. The reactive oxygen could be quantitatively assayed by measuring the intensity of CL. The addition of cytochalasin B inhibited the CL. CL production by the thioglycollate-elicited macrophages was found to be only a ninth of that by Freund's complete adjuvant-elicited macrophages, though the phagocytic activities were almost equivalent in both cases.     

Mechanism of cell death in inflamed superficial digital flexor tendon in the horse

The aim of the present study was to clarify the presence and determine the role of apoptosis in the degenerative process of the superficial digital flexor tendon (SDFT) in the horse. Samples were obtained from normal and inflamed SDFTs of horses. To detect apoptosis and to identify apoptotic cells, the samples were subjected to immunohistochemical labelling and Western blot analysis. Although a large number of cells in degenerate areas showed positive reactions with caspase-3 and single stranded DNA antibodies, cells in normal tendon samples showed very weak reactions. Excessive apoptosis was confirmed by the results of Western blot analysis, which showed a significant increase in activated caspase-3 protein in the inflamed SDFTs, suggesting that apoptosis occurred in the tendinocytes via a caspase-3-dependent pathway. This is the first report of excessive apoptosis in inflamed SDFT of the horse. The results indicate that apoptosis may play an important role in the process of degeneration of the tendon as well as other tissues.     

Regulation of the human T-cell response toSchistosoma japonicum egg antigen by concomitant cellular and humoral mechanisms in vitro

Serum-mediated regulation of T-cell responses specific for soluble egg antigen (SEA) ofSchistosoma japonicum was tested in human hosts. When we added autologous serum to SEA-specific human T-cell lines (CD3+, 4+, 8–), we observed suppression of T-cell proliferation, and this suppressive activity was detected in the immunoglobulin-G2 (IgG₂) subclass. Suppression was dose-dependent and antigen-specific. T-cell proliferation induced by only one SEA fraction of >18 kDa was modulated in the presence of 100 g/ml autologous as well as allogeneic infected IgG₂. This SEA fractiondriven proliferation was also regulated by suppressor T-cells through distinct suppressive mechanisms. Our results suggest that T-cell responses to a particular component(s) of SEA are strictly regulated through both cellular and humoral mechanisms in human chronicS. japonicum infection.     

Nature and significance of calcium oxalate crystals in normal human thyroid gland

To elucidate the significance and nature of calcium oxalate crystals in the thyroid, we studied these crystals clinicopathologically and immunohistochemically in 182 normal thyroids from patients autopsied within 5 h of death. Under polarized light, calcium oxalate crystals showed brilliant birefringence and were invariably found within the colloid. The crystals were found in 73.1% of all cases but were more prevalent and denser in older individuals, with the highest prevalence (85.2%) being observed in those over 70 years of age. No crystals were seen in those under 10 years of age. Although underlying diseases seemed to have little influence, post-mortem delay apparently affected the prevalence and density of occurrence since the crystals tended to disappear with hours after death. An immunohistochemical study using anti-thyroid hormone antibodies revealed that the crystals were within negatively or weakly stained colloid and were not common in strongly stained colloid. These findings support the hypothesis that the occurrence of calcium oxalate crystals in normal human thyroid is associated with a low functional state of the thyroid follicles.