Adenylate cyclase activation by cholera toxin in pig epidermis: an obligatory role of the GTP-regulatory protein.

Cholera toxin (CT) stimulates the epidermal adenylate cyclase system in vitro. This stimulation was demonstrated in the skin (slice) floating system and the homogenate (membrane) assay system. With the floating system, the addition of CT to the incubation medium caused a marked accumulation of cAMP intracellularly, which was both dose- and time-dependent. A 1-h lag time was present before activation started. Pretreatment of the skin with CT changed the nature of the stimulatory effect caused by epinephrine and histamine, i.e., the transient accumulation of cAMP (a peak at 5 min and subsequent decrease) was no longer observed but the stimulation became persistent. With the membrane assay system in which the receptor components had been uncoupled, adenylate cyclase activities were markedly stimulated by CT (with guanosine-5'-triphosphate, GTP), guanylyl-beta,gamma-imidodiphosphate (GTP-analog, Gpp[NH]p), or sodium fluoride. The stimulation was both dose- and time-dependent without an initial time lag. Either CT or Gpp[NH]p could fully activate adenylate cyclase, and the simultaneous addition of both did not cause further additive stimulation. These data are consistent with the view that the GTP-regulatory protein plays a key role in the activation of adenylate cyclase, and that CT both activates the catalytic unit and modifies the response to receptor hormones through its action on this protein.

"Leaky" epidermal cells contain a complete receptor-mediated adenylate cyclase system with an accessible GTP regulatory protein.

Hormone sensitivity to epinephrine or histamine of the adenylate cyclase system in pig skin is very labile to homogenization. We have developed a new adenylate cyclase receptor-mediated assay system with trypsinized epidermal cells which are treated with hypotonic shock. This new assay system maintained the hormonal sensitivity, as both epinephrine and histamine clearly stimulated cyclic AMP production. Moreover, the Ka for each hormone on this system was similar to that obtained from the floating pig skin slice system. Receptor-adenylate cyclase unit (coupling) in this assay system is therefore preserved as it occurs in intact tissue or cells. Because of the "leaky" nature of our preparation, phosphorylated compounds such as GTP and its analogue and NaF can penetrate the cell membrane and stimulate cyclic AMP production. In this system refractoriness is still maintained to subsequent stimulation by a receptor activator, and cholera toxin can be shown to dramatically increase the activity of GTP on the GTP binding protein, presumably by preventing GTP hydrolysis.

[Anesthetic management of a patient with hypohidrotic ectodermal dysplasia].

We anesthetized a 10-year-old girl with hypohidrotic ectodermal dysplasia for an ophthalmic surgery. Ectodermal dysplasia involves the abnormalities of ectodermal tissues and has a triad; hypohidrosis, a lack of teeth, and the scarcity of hair. Hyperthermia may occur due to the defect of sweat glands. Therefore, the body temperature must be monitored continuously. Respiratory tract infection occurs frequently due to the absence of seromucosal glands. We recommend humidifying the inspired gases during the operation. Tracheal intubation may be difficult because of maxillary and/or mandibular abnormalities. We conclude that the particular care should be taken such as the management of the body temperature, preparation for the difficult airway and the humidification of respiratory tract.

[A case of massive hemorrhage associated with the removal of longstanding intrabronchial foreign body].

A 46 year old male patient was admitted with fever and cough. A chest X-ray film revealed a foreign body shadow of a denture fragment in the right intermediate bronchus that he had swallowed one year and half ago. Rigid bronchoscopy was used to remove the foreign body under general anesthesia. During the procedure, massive hemorrhage occurred from bronchus, and the foreign body was not removed successfully and the patient sustained near cardiac arrest. Postoperatively, he recovered from the near fatal condition with support of mechanical ventilation in ICU for several days. After one month, pulmonary angiography was performed and it revealed the transfiguration of pulmonary artery and other vessels close to the foreign body. Granular tissue around the foreign body was observed by preoperative bronchoscopy. Disruption of such vessels and granular tissue by rigid and forced fiberscopy was suspected to have caused the massive bleeding. Later, the denture fragment was successfully removed by right thoracotomy. We should take this complication into consideration and preoperative fiberoptic bronchoscopy and pulmonary angiography may be beneficial to the anesthetic management of such patients.

[Comparison of therapeutic effects of SMANCS (+TAE) and Non-SMANCS/LpTAE].

Therapeutic effects of SMANCS and LpTAE were evaluated for hepatocellular carcinoma (HCC). Since June 1995, SMANCS has been used in 59 patients for their first treatment. LpTAE had been performed for HCC before introduction of SMANCS in our hospital, and 71 patients treated after 1992 were chosen for comparison with the therapeutic effect of SMANCS. Among the patients treated with SMANCS, complete and partial responses (CR and PR) were obtained in 24 cases (41%) and 17 cases (33%), respectively. SMANCS accompanied by TAE was more effective than SMANCS alone. The effects did not depend on the level of the hepatic arterial branch at which SMANCS was administered. In patients treated with LpTAE, CR and PR were obtained in 12 cases (17%) and 18 cases (25%), respectively. SMANCS was significantly more effective than LpTAE. Because of our short experience with SMANCS, we could only show a two year survival rate. The one- and two-year survival rates for SMANCS were 71% and 57%, respectively. They were not significantly different from those for LpTAE, at 80% and 60%. Despite good results of treatment for HCC, a better prognosis could not be expected by SMANCS in this study. These results may be explained as follows. The evaluating the cause of death within two years after first treatment, hepatic failure was more common in patients treated with SMANCS. After treatment by SMANCS, 11 patients (55%) died from hepatic failure. On the other hand, 4 patients (15%) died from hepatic failure after LpTAE. Although there is no significant difference of Child Pugh score, this may indicate that SMANCS has been used for patients with lesser hepatic reserve and this leads to early deaths in patients treated with SMANCS. However, because of the short experience in this study, further observation is necessary for precise evaluation of clinical efficacy of SMANCS.

Experimental and clinical evaluation of the splenic capping method in the treatment of injured spleens.

Polyglycolic acid elastic mesh was tailored and wrapped around the entire surface of experimentally injured spleens in 11 dogs, while carefully avoiding the splenic hilum, like a "hair-net", to achieve complete hemostasis by compression. All 11 dogs survived the experiment with no postoperative bleeding observed. Histological examination, performed 6 weeks postoperatively, revealed histiocytes, fibroblastic proliferation with collagen and cellular collagenized fibrous tissue forming a neocapsule covering the spleen. Hematologically, the platelet count was increased at 2 weeks postoperatively, but subsequently decreased to within the normal levels by 4 weeks. We employed this splenic capping method clinically in four cases to avoid splenectomy and sufficient hemostasis with ultimate splenic recovery was achieved in each case without any abscess formation, postoperative bleeding, or complications related to the use of the mesh. These experimental and clinical results thus indicate the efficacy and safety of the splenic capping method for preserving the injured spleen.