Poisoning due to class IA antiarrhythmic drugs. Quinidine, procainamide and disopyramide

Quinidine, procainamide and disopyramide are antiarrhythmic drugs in the class 1A category. These drugs have a low toxic to therapeutic ratio, and their use is associated with a number of serious adverse effects during long term therapy and life-threatening sequelae following acute overdose. Class 1A agents inhibit the fast inward sodium current and decrease the maximum rate of rise and amplitude of the cardiac action potential. Prolonged Q-T interval and, to a lesser extent, QRS duration may be observed at therapeutic concentrations of quinidine. With increasing plasma concentrations, progressive depression of automaticity and conduction velocity occur. 'Quinidine syncope' (a transient loss of consciousness due to paroxysmal ventricular tachycardia, frequently of the torsade de pointes type) occurs with therapeutic dosing, often in the first few days of therapy. Extracardiac adverse effects of quinidine include potentially intolerable gastrointestinal effects and hypersensitivity reactions such as fever, rash, blood dyscrasias and hepatitis. Procainamide produces electrophysiological changes that are similar to those of quinidine, although Q-T interval prolongation with the former is less pronounced at therapeutic concentrations. Hypersensitivity reactions including fever, rash and (more seriously) agranulocytosis are associated with procainamide, and a frequent adverse effect requiring cessation of therapy is the development of systemic lupus erythematosus. Of the 3 drugs, disopyramide has the most pronounced negative inotropic effects, which are especially significant in patients with pre-existing left ventricular dysfunction. As with quinidine, unexpected 'disopyramide syncope' at therapeutic concentrations has been described. Anticholinergic side effects are common with this drug and may require cessation of therapy. Disopyramide therapy may unpredictably induce severe hypoglycaemia. Severe intoxication with the class 1A agents may result from acute accidental or intentional overdose, or from accumulation of the drugs during long term therapy. Acute overdose can result in severe disturbances of cardiac conduction and hypotension, frequently accompanied by central nervous system toxicity. Decreased renal function can cause significant accumulation of procainamide and its active metabolite acecainide (N-acetyl-procainamide), resulting in severe intoxication. Mild to moderate renal dysfunction is less likely to lead to quinidine or disopyramide intoxication, unless renal failure is severe or concurrent hepatic dysfunction is present. Management of acute intoxication with class 1A drugs includes gut decontamination with provision of respiratory support and treatment of seizures as needed. Hypertonic sodium bicarbonate, by antagonising the inhibitory effect of quinidine on sodium conductance, may reverse many or all manifestations of cardiovascular toxicity.(ABSTRACT TRUNCATED AT 400 WORDS)     

日本血吸虫尾蚴至童虫期超微结构变化与生理适应的关系

本文应用透射电镜观察比较日本血吸虫尾蚴和皮肤型童虫的体壁、腺体和消化道的超微结构。结果表明,从尾蚴至皮肤型童虫转变过程,其体壁和钻腺的超微结构发生明显改变,但头腺及消化道则未见明显变化。这些变化与其相应的微环境密切相关。     

Increased expression of MHC class II antigens in rejecting canine lung allografts

Expression of major histocompatibility complex class II antigens was investigated in the normal lungs and in lung allografts of mongrel dogs after single-lung transplantation. Cryostat sections were stained with an indirect immunoperoxidase technique that used B1F6 and 7.5.10.1 as anti-MHC class II monoclonal antibodies. In the normal lungs and native lungs of the recipient dogs after single-lung transplantation, only some cells of lymphoid tissue and macrophages/dendritic cells were MHC class II-positive. During acute rejection, increased infiltration with MHC class II-positive cells in perivascular, peribronchial, and interstitial areas and intraalveolar spaces was found in lung allografts. In addition, expression of MHC class II antigens was induced on the bronchial epithelium and vascular endothelium. Induced expression of MHC class II antigens on the bronchial epithelium and vascular endothelium in rejecting lung allografts was found as early as two days after single-lung transplantation. The intensity of MHC class II antigen expression on bronchial epithelium and vascular endothelium in graft lungs increased with the progression of rejection response and directly correlated with the bronchoalveolar lavage fluid (BALF) levels of biochemical markers, as tumor necrosis factor alpha, gamma-interferon (IFN-gamma), interleukin 2 (IL-2) and soluble interleukin 2 receptor (SIL-2R). Abnormal expression of MHC class II antigens on bronchial epithelium and vascular endothelium and abnormal elevation of BALF levels of the cytokines in lung allografts could be prevented by cyclosporine (CsA) treatment. Our results suggested that MHC class II antigen expression could be induced on the bronchial epithelium and vascular endothelium of canine lung allografts during acute rejection. This abnormal expression of MHC class II antigens on bronchial epithelium and vascular endothelium of graft lungs may serve as a specific index for diagnosis of lung allograft rejection when infection as an inducing factor can be excluded. Furthermore, bronchial epithelium and vascular endothelium of lung allografts have become MHC class II-positive, and are likely to be the targets for low-grade rejection, resulting in the development of bronchiolitis obliterans and occlusive vascular disease in lung allografts.     

Electron-microscopic and immunohistochemical study of beta-2-microglobulin-related amyloidosis.

beta 2-Microglobulin (beta 2-MG)-related amyloidosis has been reported as a complication in long-term hemodialysis patients. We observed beta 2-MG amyloid deposits in synovial sheaths, bone cysts and gastric mucosa. They showed unique ultrastructural features, that is bundles or nodules consisting of curved or linear amyloid fibrils, associated with various cell reactions. The electron-microscopic histochemical study showed that they strongly stained with periodic acid-silver methenamine stain. A similar phenomenon was noticed in the spicules or bundles of amyloid fibrils in primary and secondary renal amyloidosis. With the cationic reagent toluidine blue 0, proteoglycan-like structures were observed around amyloid bundles and nodules, but not on each fibrils. Based on these results, we postulate that there is a close relationship between ultrastructural features and histochemical characteristics in beta 2-MG amyloid fibrils.     

Brain metastasis from malignant fibrous histiocytoma of the heart: case report

This is the second reported case of a malignant fibrous histiocytoma of the heart that metastasized to the brain. A 33-year-old woman developed headache, nausea, and ataxic gait 9 months after removal of the tumor from the left atrium of the heart. Computed tomographic and magnetic resonance imaging scans disclosed multiple metastatic tumors in the brain. Although dramatic improvement in her symptoms and signs followed the removal of the brain tumors, she died of tumor recurrence in the left atrium 3 months after the removal of the metastatic brain tumors.     

A case of double cancer: renal cell carcinoma and transitional cell carcinoma of urinary bladder

This is a case report on a patient with double cancer of kidney and urinary bladder. The patient was a 65-year-old female, and she was admitted with the chief complaint of gross hematuria and right flank pain. After careful examinations, she was diagnosed with right nonfunctioning kidney caused by invasive bladder cancer. Computerized tomography incidentally revealed a mass in the upper pole of the left kidney. Selective left renal arteriography showed stretched arteries and irregularity and tortuosity of the smaller vessels. She was diagnosed with double cancer of bladder and left kidney. Owing to the damage of the right renal function, left partial nephrectomy, total cystectomy, right nephroureterectomy and left ureterocutaneostomy were performed. According to DMSA scintigraphy measured 15 days later, the uptake value of the left kidney was 13.25%, compared to the preoperative value of 25.62%. To date, this case is 36th reported case in Japan.     

A case of embryonal carcinoma arising in the basal ganglia of the cerebrum]

The occurrence sites of intracranial primary germ cell tumors are most often the pineal and suprasellar regions. The histological type observed most frequently in these tumors is germinoma. Cases of embryonal carcinoma arising in the basal ganglia are rarely reported. To our knowledge, only 4 such cases have been previously reported in the literature. A case of an embryonal carcinoma arising in the basal ganglia is reported. A 17-year-old boy was admitted to our hospital on July 30, 1988 because of headache and vomiting, and a right hemiparesis. On admission, physical inspection showed no abnormalities and neurological examination revealed obtunded consciousness, a right central facial paresis and a right hemiparesis with Hoffman and Babinski reflexes. Noncontrast CT scan showed a large mass of low-to slightly high-density in the region of the left basal ganglia accompanied with midline shift and ventricular dilatation. Enhancement of the lesion was made by contrast CT scan. It was not homogeneous. Cerebral angiogram displayed a contralateral shift and an unrolling of the anterior cerebral artery, a lateral stretch of middle cerebral artery, a downward stretch of anterior choroidal artery and a tumor stain fed by the Heubner artery. On August 3, left frontotemporal craniotomy was performed. The tumor was totally removed in a piecemeal manner using microsurgical techniques. Histopathological diagnosis was mixed-type of germ cell tumor comprising embryonal carcinoma and teratoma. Postoperative CT scan showed complete disappearance of the tumor. A course of radiation of 4950 rads and two courses of a combination chemotherapy with cis-platinum, vinblastine and bleomycin were given within 3 months after the operation.(ABSTRACT TRUNCATED AT 250 WORDS)