Myosin II is involved in transmitter release at synapses formed between rat sympathetic neurons in culture.

The presynaptic function of myosin II was studied at cholinergic synapses formed between rat superior cervical ganglion neurons in culture. Immunofluorescent staining showed that myosin II was colocalized with synaptophysin at the presynaptic nerve terminals. Antimyosin II antibody introduced into presynaptic neurons inhibited synaptic transmission. Transmission was also inhibited in a dose-dependent manner by two inhibitors of myosin light chain kinase: a peptide, SM-1, and an organic inhibitor, wortmannin. The inhibition produced by these agents was dependent on presynaptic activity. Extracellularly applied wortmannin also blocked synaptic transmission, but its effects were slower in onset. Wortmannin also decreased postsynaptic potentials and post-tetanic potentiation in intact superior cervical ganglia. These results suggest a model in which myosin light chain kinase phosphorylates myosin, and the resultant change in actin-myosin interactions is involved in neurotransmitter release.

Tiludronate inhibits protein tyrosine phosphatase activity in osteoclasts.

Signaling pathways mediated by tyrosine phosphorylation and dephosphorylation have been reported to be involved in the regulation of cytoskeletal organization in osteoclasts, the principal cells responsible for bone resorption. We examined the effects of tiludronate [(4-chlorophenyl)thiomethylene bisphosphonate] on the cytoskeleton and the balance of phosphotyrosine levels in osteoclast-like multinucleated cells (OCLs) formed in cocultures of mouse osteoblastic cells and bone marrow cells. When OCLs were placed on plastic dishes in the presence of 10% fetal bovine serum, they formed a ringed structure of F-actin dots (actin ring) within 2 h. Tiludronate did not inhibit the process of actin ring formation, but it disrupted preformed actin rings in a time- and a dose-dependent manner. Western blot analysis using an antiphosphotyrosine antibody revealed that tyrosine phosphorylation of certain proteins in OCLs was stimulated by tiludronate added to the purified OCLs. Tyrosine kinase activity of the p60c-src immunoprecipitated from cell lysates of the purified OCLs was not affected by tiludronate directly added to the kinase assay. OCL lysates stimulated dephosphorylation of tyrosine-phosphorylated substrates such as phosphoneuroprotein 14 and epidermal growth factor receptors. Like sodium orthovanadate, an inhibitor of protein tyrosine phosphatases, tiludronate dose-dependently inhibited tyrosine dephosphorylation of those substrates induced by OCL lysates. These findings suggest that tiludronate disrupts the preformed actin rings and suppresses bone-resorbing activity by inhibiting protein tyrosine phosphatases in osteoclasts.

The role of nitric oxide in the gastric acid secretion induced by ischemia-reperfusion in the pylorus-ligated rat.

In a rat model of the ischemia-reperfusion with pylorus ligation, gastric ulcer was formed, although gastric acid secretion was reduced. When the polymorphonuclear leukocytes were inactivated in advance, gastric ulcer was not formed, but acid secretion was increased, indicating that gastric acid is not a cause of the ulcer formation in this model. The mechanism of gastric acid suppression accompanied by ischemia-reperfusion was examined in relation to the role of oxygen-free radicals in this rat model. Prior administration of superoxide dismutase did not modulate acid secretion, but N-nitro-L-arginine methyl ester (L-NAME) increased acid secretion. The action of L-NAME was antagonized specifically by L-arginine, but not by D-arginine. S-nitroso-N-acetylpenicillamine did not inhibit basal acid secretion but antagonized the action of L-NAME. Aminoguanidine increased significantly the gastric acid output that was suppressed by ischemia-reperfusion. When polymorphonuclear leukocytes were inactivated by treatment with their antibody, the gastric acid output recovered to the level in the pylorus-ligated rat without ischemia-reperfusion. These results suggested that nitric oxide (NO) produced by the infiltrated polymorphonuclear leukocytes plays an important role in the suppression of acid secretion induced by ischemia-reperfusion.

Histo-chemical studies on the anti-ulcer effect of bamboo grass in rats.

Oral administration of a hot-water extract (Folin) of bamboo grass (Sasa albomarginata Makino & Shibata) significantly reduced the incidence of water-immersion and restraint stress-, ethanol-induced and indomethacin-induced gastric ulcers in rats. Histological examination of the Folin-treated gastric mucosa showed that microscopic blood clots overlaid the superficial epithelium, maintaining the cellular integrity of gastric mucosa, especially against stress ulcer. In addition, Folin suppressed the incidence of hyperaemia and a decline of acid mucopolysaccharides in the ethanol-induced ulcer. Folin suppressed a release of histamine from rat mast cells, and stabilized erythrocytes and accelerated their agglutination under acid conditions. These results suggest that a microscopic haemostatic effect of Folin reinforced by a membrane-stabilizing effect might be responsible for the prevention of the gastric lesions.

[Toxicological studies of a new cephamycin, MT-141. II. Its subacute toxicity in rats].

In this subacute study, male and female rats were administered with 100, 200, 400, 800 and 1,600 mg/kg/day of MT-141 through an intramuscular (i.m.) route or with 50, 100, 200, 400 and 800 mg/kg/day through an intravenous (i.v.) route for 30 days. MT-141 did not cause lethal effect on male and female rats even at the high dosage of 1,600 mg/kg/day i.m. (approx. one-6th of LD50) and 800 mg/kg/day i.v. (approx. one-8th of LD50). Histopathological findings revealed that MT-141 induced slight local irritation at the sites of i.m. and i.v. injection. Only at a high dose of 1,600 mg/kg/day i.m., MT-141 reduced significantly the gain of body weight in male rats, which was closely related to the decrease of food intake. A slight decrease in serum Cr. and Glc. was observed in male rats at the doses more than 200 mg/kg/day i.m. and a slight decrease of liver weight at the doses more than 800 mg/kg/day i.m., while a slight increase of serum CPK, GOT, A1-P and LDH was perceived at the doses more than 800 mg/kg/day i.m. The distention of cecum was induced by the doses more than 400 mg/kg/day i.m. but histopathological findings revealed no abnormality in the cecum. These results suggest that MT-141 at the dosage level of 1,600 mg/kg/day i.m. causes nonspecific slight toxicity based on the disturbance of nourishment in male rats. In female rats given 100 to 1,600 mg/kg/day i.m., MT-141 at the high doses induced a slight increase of serum GOT, LDH and CPK and distention of the cecum. It is assumed from these results that MT-141 at the dosage level of 1,600 mg/kg/day causes nonspecific slight toxicity in female rats. In male rats given 50 to 800 mg/kg/day through an i.v. route, the level of serum Glc. and Cr. and the liver weight slightly decreased at the doses more than 200 mg/kg/day i.v. The cecum distended at the doses more than 100 mg/kg/day i.v. The dose of 800 mg/kg/day i.v. increased the activity of LDH and CPK in the serum. In female rats, MT-141 raised slightly the level of serum GOT, A1-P, LDH and CPK even at the doses more than 400 mg/kg/day i.v., reduced the liver weight at the dose of 800 mg/kg/day i.v. and distended the cecum at the all doses. These results suggest that MT-141 at the dosage level of 800 mg/kg/day i.v. induces nonspecific slight toxicity in male and female rats.(ABSTRACT TRUNCATED AT 400 WORDS)

[The effect of stellate ganglion block therapy on tonsillitis].

We examined a 35-year-old male patient with recurrent tonsillitis who did not respond to operation and drug therapy and we treated him by stellate ganglion block (SGB) alone. The clinical symptoms improved by the SGB. There was no subsequent recurrence. The result suggests that SGB therapy is effective for recurrent tonsillitis.

[A 5-year-old patient with allergic diseases responsive to stellate ganglion block].

We examined a 5-year-old boy with allergic rhinitis, chronic sinusitis, atopic dermatitis, and tendency to suffer common cold, who responded to stellate ganglion block (SGB). SGB therapy was extremely effective for this patient. The result suggests that SGB therapy should be performed on patients with allergic diseases resistant to drug and diet therapy. Furthermore, the indication for nerve block therapy, such as SGB, may be extended even to pediatric patients.

[Treatment of cancer pain with the percutaneous electrocoagulation of spinal nerves].

To our knowledge, this is the first report of high-frequency thermocoagulation applied to the spinal root. We treated 34 patients suffering from cancer pain with this technique. Among these patients, cancer pain occurred due to intrapelvic metastasis in 11 patients, and 13 complained of chest pain due to cancer. Every patient was considered to have good or excellent response when his or her pain score was reduced to 6 points or less from the score before thermocoagulation; 10 points. Based on this criterion, 54.5% and 30.8% of the above-mentioned patients showed good and excellent responses respectively one month after treatment. This technique, therefore, was considered to be effective with less side effects compared with other nerve blocking techniques.

[The administration of continuous epidural block under prone position with fluoroscopic guidance].

Continuous epidural block is often used for the treatment of pain. But there have been unsuccessful cases by the routine blind method. We devised a modified method of administering continuous epidural block under prone position with fluoroscopic guidance. The purpose of this study was to evaluate the utility of our modified method. There were 18 cases with pain of lumbar region and 28 cases of thoracocervical region in whom it was not possible to obtain successful control of pain by routine method. By our method, 14 cases (77.8%) with pain of lumbar region and 24 cases (85.7%) of thoracocervical region had effective epidural catheterization. There was no complication. As unsuccessful cases were accompanied with epidural adhesion or psychological disease, they might have no indication for continuous epidural block.

[Thoracic and lumbar sympathetic ganglion block for post herpetic neuralgia].

Of 2,667 patients with herpes zoster who visited our hospital between January 1972 and March 1989, 136 patients whose treatments were started after more than 6 months following the onset were subjects of the present study. Thus we performed a retrospective study of the therapeutic effects of sympathetic ganglion block (using alcohol) on postherpetic neuralgia left untreated for more than 6 months after the onset. After more than 1 year following the onset, the disease was nearly or completely cured in 9 of 37 patients (24%) treated with sympathetic ganglion block with alcohol and in 6 of 34 (17.6%) without the treatment. Thus the patients who underwent sympathetic ganglion block with alcohol tended to show better results. The above findings suggest that, in patients with postherpetic neuralgia in whom the initiation of treatment was delayed, treatment mainly consisting of thoracic or lumbar sympathetic ganglion block using alcohol in combination with antidepressants and antianxiety drugs can greatly improve patients' activities of daily life and that, at present, this method is most effective in relieving postherpetic neuralgia.