Dynorphins directly inhibit neuronal nicotinic acetylcholine receptors in PC12 cells

The authors have previously reported that dynorphin A (1-17), an endogenous kappa opioid agonist, inhibits the current mediated through neuronal nicotinic acetylcholine receptors (nAChRs) without the involvement of opioid receptors or G-proteins. We have further characterized this action to elucidate the mechanisms. The nicotine-induced current was studied in PC12 cells using patch-clamp techniques. In the whole-cell configuration, four kinds of dynorphins with different lengths, dynorphin A (1-17) (1-13) (2-13) and (1-8), similarly inhibited the nicotine-induced inward current at 1 microM and accelerated the current decay. The inhibition by dynorphin A (1-17) was not antagonized by the increasing concentrations of nicotine. The current-voltage relationship revealed that dynorphin's inhibition was voltage independent at the membrane potentials from -30 to -70 mV. The inhibition was not affected by pretreatment with pertussis toxin (PTX) or inclusion of staurosporine into the pipette solution. The inhibitory effect of dynorphin A (1-17) was well preserved in the outside-out patch configuration. Analysis of the nicotine-induced noise and single-channel kinetics revealed that dynorphin A(1-17) reduced open time without changing the amplitude of the unitary current. We found that the inhibitory effect on neuronal nAChRs is shared by all four dynorphins studied. The inhibition appears to be non-competitive and voltage independent. The outside-out recording together with other experiments indicated that a major part of this inhibition is not mediated through cytoplasmic messengers, but based on the direct action of dynorphins on neuronal nAChRs leading to the reduction of open time.     

An angiogenesis inhibitor E7820 shows broad-spectrum tumor growth inhibition in a xenograft model: possible value of integrin alpha2 on platelets as a biological marker.

We reported previously that an angiogenesis inhibitor, E7820, inhibits in vitro tube formation of human umbilical vein endothelial cell through the suppression of integrin alpha2 expression. Here we describe the antiangiogenic and antitumor effects of E7820 in mice and discuss the feasibility of using platelet integrin alpha2 expression on platelets as a biological marker of the efficacy of E7820. Oral administration of E7820 significantly inhibited basic fibroblast growth factor-induced angiogenesis in Matrigel implants and human colon WiDr tumor-induced angiogenesis in a dorsal air sac model. Twice-daily treatment with E7820 clearly inhibited the s.c. tumor growth of seven tumor cell lines derived from human colon, breast, pancreas, and kidney, and completely suppressed the growth of human pancreatic KP-1 and human colon LoVo cell lines. Moreover, E7820 significantly inhibited the growth of KP-1 and human colon tumor Colo320DM cells orthotopically implanted in the pancreas and cecum, respectively. The efficacy of E7820 was comparable in the s.c. and orthotopic transplantation models. Immunohistochemical analyses using anti-CD31 antibody showed that E7820 significantly reduced microvessel density in orthotopically implanted KP-1 tumor. E7820 reduced integrin alpha2 expression on a megakaryocytic cell line, Dami cells, induced by phorbol 12-myristate 13-acetate treatment. It also decreased the expression level of integrin alpha2 on platelets withdrawn from mice bearing s.c. KP-1 tumor at a dosage close to that affording antitumor activity. These data demonstrate that E7820 showed a broad-spectrum antitumor effect in mice through inhibition of angiogenesis and indicate that the decrease of integrin alpha2 on platelets might serve as a biological marker for the antitumor efficacy of E7820.     

Tumor lysis syndrome in widely metastatic small-cell lung cancer

Tumor lysis syndrome is a rare complication of nonhematologic malignancies that results from massive necrosis of neoplastic cells after chemotherapy. This syndrome consists of life-threatening metabolic derangements, including severe hyperphosphatemia, hyperkalemia, hyperuricemia, and hypocalcemia, and may result in renal failure and death if not recognized early and treated appropriately. We report a case of tumor lysis syndrome after induction chemotherapy in a patient with widely metastatic smallcell lung cancer. This case emphasizes the importance of awareness and early treatment of this syndrome.     

Seven-year survivor with malignant melanoma of the anus without radical surgery

We report a case of a long-term survivor with malignant melanoma of the anus who did not undergo radical surgery. A 71-year-old woman who presented with anal bleeding and anal tumor underwent an excisional biopsy in September 1985. The biopsy specimen was a lobulated, polypoid, pigmented mass 2 cm in diameter, that had been located on the anterior wall of the anus. A satellite nodule 7 mm in diameter was found on the left wall of the anus at the level of the dentate line. Both tumors were histologically diagnosed as malignant melanoma. The primary tumor was 6 mm thick. Melanoma cells were present microscopically at the cut end of the rectum. Because of her history of ischemic heart disease, the patient rejected our recommendation that she undergo radical surgery, and received 10 courses of carboplatin 20 mg intramuscularly and OK-432 10 K.E. (Klinische Einheit) intradermally every week. A single, pigmented metastatic inguinal lymph node developed and was excised in June 1987. A recurrent tumor was detected in the rectum in October 1992, so again we recommended radical surgery. The patient rejected radical surgery again, and received 12 courses of carboplatin 10 mg intramuscularly every 2 weeks. She died of disease at home in July 1993 after surviving for 7 years and 10 months. An autopsy was not performed. This case shows that local excision of the primary lesion may be appropriate to preserve the quality of life of patients with early-stage malignant melanoma of the anus.     

Role of Sialylglycoconjugate(s) in the Initial Phase of Metastasis of Liver-metastatic RAW117 Lymphoma Cells

To elucidate the early events of blood-borne metastasis under actual blood flow, real-time trafficking of RAW117 large cell lymphoma cells, namely parental RAW117-P and liver-metastatic RAW117-H10 cells, was investigated using positron emission tomography (PET). Both types of cells accumulated in the liver immediately after injection via the portal vein, and were eliminated from the liver time-dependently. The elimination rate of RAW117-H10 cells, however, was slower than that of RAW117-P cells, suggesting that RAW117-H10 cells interact more strongly with hepatic sinusoidal endothelium than the parental cells. This result correlated with the metastatic potential of these cells: RAW117-H10 cells metastasized in the liver to a greater extent than RAW117-P cells after injection via this route. To investigate the role of sialylglycoconjugates in the interaction of RAW117-H10 cells with the hepatic endothelium after injection via the portal vein, the trafficking of RAW117-H10 cells was examined after the cells had been treated with sialidase. The elimination rate of RAW117-H10 cells from liver was observed to be greatly accelerated by sialidase treatment. To elucidate what kind of sialylglycoconjugates is related to this phenomenon, we analyzed the distribution of sialyl Lewis A and sialyl Lewis X antigens of both sublines of RAW117 by using flow cytometry. RAW117-H10 cells were found to express a much higher level of sialyl Lewis A than RAW117-P cells, whereas the amount of sialyl Lewis X did not differ significantly. These findings suggest that some sialylglycoconjugates, perhaps sialyl Lewis A in particular, play an important role in the initial interaction of RAW117-H10 cells with the hepatic endothelium, leading to metastasis.     

Involvement of M3 muscarinic receptors of the spinal cord in formalin-induced nociception in mice

Subcutaneous injection of formalin into a paw of mice caused two distinct phases of licking and biting, first phase (1-5 min) and the second phase (7-30 min) after the injection. The muscarinic antagonist atropine (0.1-10 ng, i.t.) and the M(3) receptor antagonist 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP) (0.1-20 ng, i.t.) inhibited the second phase of this response, whereas higher doses of atropine (20-100 ng, i.t.) did not cause inhibition. The M(1) muscarinic receptor antagonist pirenzepine (10-100 ng, i.t.) did not inhibit either the first or the second phase response, but a high dose of pirenzepine (1000 ng, i.t.) tended to inhibit the second phase response. On the other hand, the M(2) muscarinic receptor antagonist 11-?(2-[(diethylamino)methyl]-1-piperidinyl?acetyl)-5, 11-dihydro-6H-pyrido(2,3-b)(1,4)benzodiazepine-6-one (AF-DX116; 10-1000 ng, i.t.) had no effect on either the first or the second phase of response. The opioid receptor antagonist naloxone did not affect the 4-DAMP-induced anti-nociceptive response. The i.t. injection of the acetylcholinesterase inhibitor neostigmine (25 ng) significantly inhibited only the second phase. The acetylcholine (ACh) depletor hemicholinium-3 (HC-3) (1 microg, i.t.) completely abolished the 4-DAMP-induced anti-nociceptive response. The ACh content of the spinal cord was significantly increased 14 min after formalin injection. This significant increase in the ACh content was inhibited by pretreatment with 4-DAMP (10 ng, i.t.). These results suggest that endogenous ACh in the spinal cord acts as a transmitter anti-nociception, and that ACh release regulated by presynaptic M(3) muscarinic receptors in the spinal cord is involved in the second phase of nociception induced by formalin.     

Pharmacological characterization of a novel AVP(4-9) binding site in rat hippocampus

pGlu-Asn-Cys (Cys)-Pro-Arg-Gly-NH(2) (AVP(4-9)), a major metabolite C-terminal fragment of Arginine(8)-vasopressin (AVP), improves the disruption of the learning and memory, and is a far more potent in the mnemonic function than AVP. In this study, we pharmacologically characterized its putative binding site and mechanism of intracellular signaling. Radioligand binding assay showed that [35S]AVP(4-9) could detect specific binding sites in the rat hippocampus membrane preparations, and the binding site was specifically displaced by AVP(4-9) but not by either V(1) or V(2) antagonists. Furthermore, [35S]AVP(4-9) could not detect the cloned rat V(1a), V(1b) and V(2) vasopressin receptors. Even at a low doses (10-100 pM), AVP(4-9) caused an increase in both inositol(1,4, 5)-trisphosphate (Ins(1,4,5)P(3)) and intracellular calcium concentrations ([Ca(2+)](i)) in rat hippocampal cells. The AVP(4-9)-induced [Ca(2+)](i) increase was partially inhibited by the absence of Ca(2+) or by Ca(2+)-channel blocker, suggesting that AVP(4-9) caused the [Ca(2+)](i) increase via release from intracellular calcium store as well as influx from extracellular calcium. For the first time, this study provides evidence to show that AVP(4-9) activates Ins(1,4,5)P(3)/[Ca(2+)](i) pathway through a novel type of receptor in rat hippocampus, which might be potentially important in improving the mnemonic function.     

A case with esophageal carcinoma associated with metastatic pulmonary tumor in lung cancer at seven years after the resection of lung cancer

A 69-year-old woman was admitted to our hospital because of dysphasia. The upper G-I examination showed a stenosis at the middle thoracic esophagus and poorly differentiated adenocarcinoma was revealed histologically. Chest CT scan showed a mass shadow in the right upper lobe of the lung. She had undergone a partial resection of right upper lobe because of lung cancer seven years before. She was diagnosed as metachrous double carcinoma of the lung and the esophagus. The method of surgery included right upper lobectomy of the lung, esophagectomy and intrathoracic esophageal reconstruction using the gastric tube. The patient manifested pneumonia due to the failure of the sutures after the surgery and died on the twentieth postoperative day. When conducting simultaneous resection of both cancer and esophageal reconstruction for the double cancer of the lung and the esophagus, it was considered necessary to conduct the anastomosis outside the thoracic cavity for the purpose of preventing the pulmonary complication due to the failure of the sutures.