Sin Hyung Lee

Mercury inhalation poisoning and acute lung injury

Acute mercury inhalation poisoning is a rare cause of acute lung injury. It is usually fatal because of progressive pulmonary failure. We experienced a patient with acute respiratory distress syndrome (ARDS) after illicit use of mercury vapor for hemorrhoid treatment; he developed acute chemical pneumonitis following exposure to mercury vapor. Prompt treatment with corticosteroids and penicillamine for acute chemical pneumonitis was instituted; radiologic pulmonary infiltrates disappeared within a week, but late phase neurologic sequelae and pulmonary interstitial fibrosis progressed.

Primary endobronchial leiomyosarcoma. Diagnosis following expectoration of tumor fragment.

A case is presented with spontaneous expectoration of a small piece of solid tissue. Pathologic examination of the expectorated tissue was found to be consistent with leiomyosarcoma. After further work-up, there was no evidence of another primary site of leiomyosarcoma except for the right lower lobe. Right lower lobectomy was performed. The surgical specimen showed a tumor that was histologically identical to the patient’s previous expectorated tissue. To the authors’ knowledge, this is the first report of partial expectoration of a primary endobronchial leiomyosarcoma.

Function of the neuronal M2 muscarinic receptor in asthmatic patients

Background : The dominant innervation of airway smooth muscle is parasympathetic fibers which are carried in the vagus nerve. Activation of these cholinergic nerves releases acetylcholine which binds to muscarinic receptors on the smooth muscle causing bronchocontraction. Acetylcholine also feeds back onto neuronal muscarinic receptors located on the postganglionic cholinergic nerves. Stimulation of these receptors further inhibits acetylcholine release, so these , muscarinic receptors act as autoreceptors. Loss of function of these receptors, as it occurs in animal models of hyperresponsiveness, leads to an increase in vagally mediated hyperresponsiveness. However, there are limited data pertaining to whether there are dysfunctions of these receptors in patients with asthma. The aim of this study is to determine whether there are dysfunction of muscarinic receptors in asthmatic patients and difference of function of these receptors according to severity of asthma. Method : We studied twenty-seven patients with asthma who were registered at Pulmonology Division of Korea University Hospital. They all met asthma criteria of ATS. Of these patients, eleven patients were categorized as having mild asthma, eight patients moderate asthma and eight patients severe asthma according to severity by NAEPP Expert Panel Report 2(1997). All subjects were free of recent upper respiratory tract infection within 2 weeks and showed positive methacholine challenge test ( muscarinic receptor agonist pilocarpine() through inhalation was performed be fore the routine procedures. Results : Eleven subjects with mild asthma and eight subjects with moderate asthma showed significant increase of from 5.305.23mg/ml(meanSD) to 20.8222.56mg/ml(p=0.004) and from 2.791.51mg/ml to 4.673.53mg/ml(p=0.012) after pilocarpine inhalation, respectively. However, in the eight subjects with severe asthma significant increase of from l.761.50mg/ml to 3.184.03mg/ml(p=0.161) after pilocarpine inhalation was not found. Conclusion : In subjects with mild and moderate asthma, function of muscarinic receptors was normal, but there was a dysfunction of these receptors in subjects with severe asthma. ηlese results suggest that function of muscarinic receptors is different according to severity of asthma.