Although intestinal paralysis is often observed in paraquat (PQ) poisoning, the mechanism remains unclear. We used isolated guinea pig ileal preparations to determine the mechanism of PQ suppression of intestinal contraction. PQ pretreatment (10, 30 or 100mmol) significantly suppressed ACh-induced contraction in ileal preparations in aconcentration-dependent manner, but had no effect on histamine (Hist)-or KCl-induced contraction. When PQ was added cumulatively during contraction induced by 1μmol of ACh, 1μmol of Hist or 50mmol of KCl, each type of contraction was significantly inhibited. In β-escin-skinned ileal longitudinal muscle preparations, at a fixed Ca²⁺ concentration (pCa=6.0), cumulative addition of PQ (3 to 100mmol) suppressed the Ca²⁺ contraction in a concentration-dependent manner, but this suppression was observed only for 100mmol of PQ in the presence of GTPγs (100μmol). These results suggest that the suppressive effect of PQ on intestinal contraction may be associated with inhibition of the muscarinic-ACh receptor, a lowered Ca²⁺ sensitization in the intracellular contractile proteins and adisturbance of the intracellular signal transduction system.

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Despite improvement in surgical technology and postoperative critical care, mortality from ruptured abdominal aortic aneurysms (AAA) remains high. We evaluated 9 consecutive patients with ruptured AAA who had cardiopulmonary arrest on arrival (CPAOA) at our medical center. The 7 men and 2 women had a mean age of 73 years with a range of 66 to 83 years. Seven patients were transported from hospitals and the others were transferred directly from the sites of the collapse. Initial diagnoses in the previous hospital were abdominal pain of unknown origin in 4, ureterolithiasis in 2 and ruptured AAA in only one, although there was a previous diagnosis of AAA in 3 patients (33%). The other 9 patients all developed cardiopulmonary arrest in the ambulance and received cardiopulmonary resuscitation (CPR). Electrocardiograms in our emergency room showed electromechanical dissociation in 6 patients and standstill in 3. Return to spontaneous circulation was obtained by CPR in the emergency room in 6 patients, and 5 of these 6 underwent emergency surgery. Cardiac arrest developed during surgery in 2 of the 5, and aneurysms were resected and replaced with a Dacron graft in the remaining 3. One patient recovered fully and returned to his usual life. One case who recovered consciousness postoperatively died of multiorgan dysfunction on the 3rd postoperative day. The remaining patient was diagnosed as having brain death postoperatively. In conclusion, to reduce the mortality from ruptured AAA, correct initial diagnosis and expeditious preoperative management are most important.

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Acute occlusion of the descending thoracic aorta causes many clinical problems, although it is rare. A 59-year-old man had sudden onset of coldness in his legs. On a CT scan, a thoracic aortic aneurysm with a mural thrombus was detected. After 4 hours, pulsations in the lower extremities reappeared. However, he died three days after onset. In the pathological findings, all visceral organs were necrosed. The second patient, a 74-year-old woman, had sudden onset of back pain. Both femoral pulses were impalpable. On a CT scan, a dissecting aortic aneurysm (DeBakey I type) was detected. After 4 hours, a right axillo-bifemoral bypass was performed. However, she died on the 8th postoperative day. In the pathological findings, all visceral organs were necrosed. When we detect an acute occlusion of the descending thoracic aorta, some immediately examinations for ischemic injury of visceral organs are very important for diagnosis and treatment.

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We report a case of severe airway sequelae following inhalation injury. A 52 years old male was transferred to our hospital because of severe inhalation injury. Acute respiratory failure was treated by frequent tracheobronchial lavage using bronchofiberscope (BFS) under Pressure Support Ventilation with PEEP and superimposed high frequency jet ventilation. Severe tracheal stenosis and endobronchial multiple granuloma (polyposis) developed after one month. Life-threatening tracheal stenosis was treated by Nd-YAG Laser coagulation, and a silicone stent was inserted against recurrent stenosis up to the 693rd day. Endobronchial multiple granuloma subsided spontaneously following cicatrizational stenosis. After about one year from his admission, an ectatic change gradually developed in the peripheral bronchus and pulmonary fibrosis. The etiology of these airway sequelae were considered to be related to the destroyed basal membrane of the airways, and to the prolonged accompanying inflammation. The frequency of the sequelaelike cicatrizaional stenosis, inflammatory granuloma, peripheral bronchoectasia, pulmonary fibrosis will increase, as treatment in the acute phase improves. In cases of severe inhalation injury, it is important to investigate airway sequelae over a long follow-up period, and BFS is the most valuable means not only for treatment but also for investigation.

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On 15th June 1995, an accidental explosion in a chemical plant in Aizu where benzyl chloroformate was synthesized from phosgen and benzyl alcohol killed one man and injured 35 others. The plant was destroyed, and benzyl chloroformate designated sprayed out of it. The dead man was designated DNR (do not resuscitate), because of the blast injury. In two men the chemical compound poured all over the body and they were diagnosed as having respiratory distress and chemical burns. Another mildly affected patient suffered from mucosal membrane irritative symptoms. From this experience, it was realized that gas masks are necessary as an immediate response, so 10 masks were provided. And we mailed a questionnaire on chemical compounds used by the chemical plants around the area. Very few traumatic centers have paid attention to the possibility of having to cope with such a crisis.

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