Gastric blood flow responses to autonomic nerve stimulation and related pharmacological studies in rats

The effects of autonomic nerve stimulation on rat gastric blood flow (GBF) were studied using a cross thermocouple method. Stimulation of the periarterial nerve bundles along the left gastric artery produced a decrease in GBF which was antagonized by phenoxybenzamine (0.05 mg kg-1 i.v.), but not by propranolol (1 mg kg-1 i.v.). Stimulation of the vagus nerves elicited an increase in GBF, within a latency of 20 s, which was not apparently affected by atropine (0.15 and 1.5 mg kg-1 i.v.) but was completely blocked by hexamethonium (10 mg kg-1 i.v.). The GBF increase due to acetylcholine (0.25 micrograms rat-1 i.a.), was markedly blocked by atropine (0.15 mg kg-1 i.v.). Vagal stimulation also produced both the cholinergic excitation and non-cholinergic inhibition of gastric motility. The vagally induced GBF increase was little affected by any pretreatment with phentolamine, propranolol, indomethacin or aprotinin. These results suggest that sympathetic nerve stimulation creases GBF through alpha-adrenoceptors and parasympathetic nerve stimulation increases GBF through a non-cholinergic mechanism in rats and that the GBF increase may result from a primary dilator effect of vagal stimulation on the blood vessels because of the immediate initiation of the response.     

Effect of the new zinc compound beta-alanyl-L-histidinato zinc on bone metabolism in elderly rats

The effect of a new zinc compound beta-alanyl-L-histidinato zinc (AHZ) on bone metabolism was investigated in aged rats (30 weeks old). AHZ (1.0, 2.5 and 7.5 mg/100 g body weight) was orally administered to rats 3 times at 24-hour intervals, and the rats were bled 24 h after the last administration. The administration of AHZ (7.5 mg/100 g) did not cause an appreciable alteration of calcium and inorganic phosphorus concentrations in the serum, and zinc, calcium and deoxyribonucleic acid contents in the femoral diaphysis were significantly increased by the administration of AHZ (7.5 mg/100 g). The bone alkaline phosphatase activity was significantly increased by doses of 1.0-7.5 mg AHZ/100 g. These results suggest that AHZ has a stimulatory effect on bone formation and calcification in aged rats.     

Randomized phase II study of immunomodulator Z-100 in patients with stage IIIB cervical cancer with radiation therapy

OBJECTIVE: To find the optimal dose of immunomodulator Z-100 in patients with stage IIIB squamous cell carcinoma of the cervix in combination with radiation therapy. METHODS: The patients were randomly assigned to the dosage levels of 2, 20 or 40 mug of Z-100. Z-100 was subcutaneously injected twice a week during radiotherapy and once in two weeks during the maintenance period. The response rate after radiotherapy was evaluated, and the optimal clinical dosage was then determined. Safety of Z-100 was evaluated during the radiation therapy and maintenance therapy. Survival was also evaluated. RESULTS: A total of 116 patients were entered. The adverse reactions were not dose-dependent and no serious toxicities were observed. The response rates were 72.2% (26/36) in the 2 microg group, 84.6% (33/39) in the 20 microg group and 94.3% (33/35) in the 40 microg group (P = 0.006). However, the survival was not significantly different. CONCLUSIONS: The optimal dose of Z-100 was determined to be 40 mug in combination with radiation therapy for stage IIIB cervical cancer. However, impact of Z-100 on survival must be determined by the placebo controlled randomized trial, because survival benefit was not observed in this small population study.     

Bcl-2 is a key regulator for the retinoic acid-induced apoptotic cell death in neuroblastoma

Retinoic acid (RA) has been shown to induce neuronal differentiation and/or apoptosis, and is widely used as a chemotherapeutic agent for treating the patients with neuroblastoma. However, the therapeutic effect of RA is still limited. To unveil the molecular mechanism(s) inducing differentiation and apoptosis in neuroblastoma cells, we compared CHP134 and NB-39-nu cell lines, in which all-trans-RA (ATRA) induces apoptosis, with LA-N-5 and RTBM1 cell lines, in which it induces neuronal differentiation. Here, we found that Bcl-2 was strongly downregulated in CHP134 and NB-39-nu cells, whereas it was abundantly expressed in LA-N-5 and RTBM1 cells. ATRA-mediated apoptosis in CHP134 and NB-39-nu cells was associated with a significant activation of caspase-9 and caspase-3 as well as cytoplasmic release of cytochrome c from mitochondria in a p53-independent manner. Enforced expression of Bcl-2 significantly inhibited ATRA-mediated apoptosis in CHP134 cells. In addition, treatment of RTBM1 cells with a Bcl-2 inhibitor, HA14-1, enhanced apoptotic response induced by ATRA. Of note, two out of 10 sporadic neuroblastomas expressed bcl-2 at undetectable levels and underwent cell death in response to ATRA in primary cultures. Thus, our present results suggest that overexpression of Bcl-2 is one of the key mechanisms to give neuroblastoma cells the resistance against ATRA-mediated apoptosis. This may provide a new therapeutic strategy against the ATRA-resistant and aggressive neuroblastomas by combining treatment with ATRA and a Bcl-2 inhibitor.     

Antitumor activity of humanized monoclonal antibody against HM1.24 antigen in human myeloma xenograft models

A humanized monoclonal antibody against HM1.24 antigen (AHM), which is highly expressed on multiple myeloma (MM) cells, induced antibody-dependent cellular cytotoxicity (ADCC) in vitro. In this study, we further characterized AHM and evaluated its potency for clinical application. AHM bound to HM1.24 antigen with a dissociation constant of 0.35 nM, and its epitope resided between Leu116 and Leu127 of the HM1.24 antigen. Single intravenous injection of AHM significantly inhibited tumor growth in both orthotopic and ectopic human MM xenograft models. AHM reduced serum M protein levels and prolonged survival of mice intravenously inoculated with KPMM2 and ARH-77 cells. The number of KPMM2 cells in bone marrow or tumor volume of subcutaneously inoculated RPMI 8226 cells was also inhibited by AHM. The antitumor activity of AHM against tumor cells in bone marrow was diminished when the mice were pretreated with anti-Fcgamma receptor III/II antibody, demonstrating that antitumor activity by AHM requires effector cell functions in vivo. Experiments involving in vitro ADCC assays indicated that NK cells and monocytes/macrophages serve as effector cells for AHM-induced ADCC in mouse and human. Thus, AHM will provide an additional treatment option for MM.