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.     

Immunomodulation by vitamin B12: augmentation of CD8+ T lymphocytes and natural killer (NK) cell activity in vitamin B12-deficient patients by methyl-B12 treatment

It has been suggested that vitamin B12 (vit.B12) plays an important role in immune system regulation, but the details are still obscure. In order to examine the action of vit.B12 on cells of the human immune system, lymphocyte subpopulations and NK cell activity were evaluated in 11 patients with vit.B12 deficiency anaemia and in 13 control subjects. Decreases in the number of lymphocytes and CD8+ cells and in the proportion of CD4+ cells, an abnormally high CD4/CD8 ratio, and suppressed NK cell activity were noted in patients compared with control subjects. In all 11 patients and eight control subjects, these immune parameters were evaluated before and after methyl-B12 injection. The lymphocyte counts and number of CD8+ cells increased both in patients and in control subjects. The high CD4/CD8 ratio and suppressed NK cell activity were improved by methyl-B12 treatment. Augmentation of CD3-CD16+ cells occurred in patients after methyl-B12 treatment. In contrast, antibody-dependent cell-mediated cytotoxicity (ADCC) activity, lectin-stimulated lymphocyte blast formation, and serum levels of immunoglobulins were not changed by methyl-B12 treatment. These results indicate that vit.B12 might play an important role in cellular immunity, especially relativing to CD8+ cells and the NK cell system, which suggests effects on cytotoxic cells. We conclude that vit.B12 acts as an immunomodulator for cellular immunity.     

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.     

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.     

Effects of sex hormones on induction of intestinal metaplasia by X-irradiation in rats.

The influence of sex hormones on induction of intestinal rnetaplasia was examined in 5 week old Crj: CD (SD) rats of both sexes. At the age of 4 weeks, the animals were gonadectornized and given testosterone or dimethyl estradiol (DES). One week after operation, they were irradiated with two 10 Gy doses of X-rays to the gastric region at a 3 day interval for a total of 20 Gy. At the termination of the experiment, 6 months after the X-irradiation, the incidence of intestinal metaplasia with alkaline phosphatase (ALP) positive foci in males was significantly higher than in females, in orchidectomized males or orchidectomized plus DES treated rats (P <0.01). On the other hand, the incidence of intestinal metaplasia with ALPpositive foci in normal females appeared lower than in ovariectomized females (P < 0.01), and was increased in rats by treatment with testosterone or decreased by DES. Numbers of foci of intestinal metaplasias with Paneth cells and total numbers appeared to increase in males treated with DES. The results suggested a promoting role for testosterone in the development of ALP positive lesions and indicated considerable heterogeneity between intestinal metaplasia subtypes.     

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.     

Heats of dilution of poly[styrene-ran-(butyl methacrylate)] solutions measured with an automatic flow microcalorimeter

In order to obtain information about the thermodynamic behaviour of copolymers in solution, we built an automatic flow microcalorimeter equipped with a computer that satisfies the requirements of accuracy, reliability, and rapidity for the measurement of heats of dilution of copolymer solutions. By using this apparatus, the heats of dilution of the random copolymer, poly[styrene-ran-(butyl methacrylate)] in ethyl methyl ketone solutions were measured at 298 K. Furthermore, light scattering of the copolymer and its constituent homopolymer solutions was measured at 298 K. From the combination of the heat of dilution and the light scattering results, thermodynamic and intramolecular interaction parameters of the copolymer chain were determined.     

Suppression of eosinophilic airway inflammation by treatment with alpha-galactosylceramide

To clarify the essential role of NKT cells in allergy, we investigated the contribution of NKT cells to the pathogenesis of eosinophilic airway inflammation using alpha-galactosylceramide (alpha-GalCer), a selective ligand for NKT cells. Although continuous administration of alpha-GalCer during ovalbumin (OVA) sensitization increased OVA-specific IgE levels and worsened eosinophil inflammation, a single administration of alpha-GalCer at the time of OVA challenge completely prevented eosinophilic infiltration in wild-type mice. This inhibitory effect of alpha-GalCer was associated with a decrease in airway hyperresponsiveness, an increase in IFN-gamma, and decreases in IL-4, IL-5 and IL-13 levels in the bronchoalveolar lavage fluids. Analysis of lung lymphocytes revealed that production of IFN-gamma increased in NK cells, but not in T or NKT cells, following alpha-GalCer administration. Induction of vascular cell adhesion molecule-1 in the lungs of wild-type mice was also significantly attenuated by treatment with alpha-GalCer. These effects of alpha-GalCer were abrogated in J alpha281-/- mice, which lack NKT cells, and in wild-type mice treated with anti-IFN-gamma Ab. Hence, our data indicate that alpha-GalCer suppresses allergen-induced eosinophilic airway inflammation, possibly by inducing a Th1 bias that results in inhibition of eosinophil adhesion to the lung vessels.