<症例>マムシ (Agkistrodon halys Blomhoffii) 咬傷における少量抗毒素血清投与の経験 : 43症例の検討

Forty-three consecutive patients of venomous snakebite by the Japanese viper (Agkistrodon halys Blomhoffii, "Mamushi" in Japanese) were treated with an uniformly scheduled therapy from 1990 and 1994. The therapy was mainly composed of minimal dose of antivenin, methylprednisolon and cepharanthin. There were two clinical courses, i.e., the minimal envenomation course (Group A, n=14) and the severe one (Group B, n=29). Our treatment was so satisfactory that all patients of both groups fully recovered activities of daily living with neither organic disorders nor sequelae of the bitten extremities. The high appearance ratio of atypical lymphocytes (P < 0. 05) and the increased ratio of lymphocyte count to White blood cell count (P<0. 02) could be indicators that predict hich clinical courses the patients take.1990年から1994年までの5年間に当院で治療したマムシ咬傷43例について検討した. 当院では原則として抗毒素血清, ステロイド, セファランチンの投与を行っているが, 死亡例はなく, 咬傷部の機能障害を示した症例もなかった. 4例（9. 3%）に即効型過敏反応が認められた. 1例は anaphylaxy shock を呈したが治療により即時改善をみた. 遅延型血清病は入院期間中観察されなかった. McCollough らの分類により軽症例（n=14）と重症例（n=29）に分け予後因子を検討した. 治療開始前の WBC, CPK, LDH, BUN, Cr はいずれも重症化指標とはなりえなかったが, 白血球中のリンパ球比率（P<0. 02）, 異型リンパ球出現率（P<0. 05）が高い程, 重症化することが示唆された. 死亡報告が散見されるマムシ咬傷に対し受傷早期の抗毒素血清投与は有用であり, 即効型過敏反応に即座に対応すれば比較的安全に投与できるものと考えられた. しかし, 軽症例に対しての抗毒素血清投与には疑問が残り, 今後は重症化が危倶される症例を的確に選択する必要があると思われた

Functions of Muscarinic Receptor Subtypes in Gastrointestinal Smooth Muscle: A Review of Studies with Receptor-Knockout Mice

Parasympathetic signalling via muscarinic acetylcholine receptors (mAChRs) regulates gastrointestinal smooth muscle function. In most instances, the mAChR population in smooth muscle consists mainly of M2 and M3 subtypes in a roughly 80% to 20% mixture. Stimulation of these mAChRs triggers a complex array of biochemical and electrical events in the cell via associated G proteins, leading to smooth muscle contraction and facilitating gastrointestinal motility. Major signalling events induced by mAChRs include adenylyl cyclase inhibition, phosphoinositide hydrolysis, intracellular Ca2+ mobilisation, myofilament Ca2+ sensitisation, generation of non-selective cationic and chloride currents, K+ current modulation, inhibition or potentiation of voltage-dependent Ca2+ currents and membrane depolarisation. A lack of ligands with a high degree of receptor subtype selectivity and the frequent contribution of multiple receptor subtypes to responses in the same cell type have hampered studies on the signal transduction mechanisms and functions of individual mAChR subtypes. Therefore, novel strategies such as genetic manipulation are required to elucidate both the contributions of specific AChR subtypes to smooth muscle function and the underlying molecular mechanisms. In this article, we review recent studies on muscarinic function in gastrointestinal smooth muscle using mAChR subtype-knockout mice