Clinically, methylxanthines are known to be potent bronchodilators. However, methylxanthines induce contraction for many types of smooth muscle. To clarify this inconsistency, we investigated the effects of caffeine on intracellular Ca²⁺ concentration ([Ca²⁺]_i) and tension in porcine bronchial smooth muscle.

Porcine bronchial muscle rings were loaded with a Ca²⁺ indicator dye, Fura-2/AM. The light emission ratio (R340/380) of Fura-2 was recorded to estimate the change in [Ca²⁺]_i, and the isometric tension was simultaneously measured with a force displacement transducer. At the beginning of each experiment, changes in muscle tension and [Ca²⁺]_i induced by 90mM KCl were recorded as control values (100%). Thereafter, tension and [Ca²⁺]_i were recorded under the following conditions: changes induced by histamine (10^-6~10^-4M), by 90mM KCl or 0.1mM histamine in a Ca²⁺-free medium, by 2.5mM caffeine, and by 90mM KCl and 0.1mM histamine in the presence of 2.5mM caffeine. Histamine (10^-6~10^-4M) induced concentration-dependent increases in tension and [Ca²⁺]_i. In the Ca²⁺-free medium, the increases in tension and [Ca²⁺]_i induced by 90mM KCl were significantly reduced, but those induced by histamine were not. Caffeine itself caused transient increases in tension and [Ca²⁺]_i. Caffeine Suppressed the increases tension induced by histamine, but it did not suppress the increases [Ca²⁺]_i induced by histamine. Caffeine did not affect the increases tension and [Ca²⁺]_i induced by 90mM KCl. Our data suggest that the increases tension induced by histamine is mainly caused by the release of stored Ca²⁺ and that induced by high K⁺ is dependent on extracellular Ca²⁺. Caffeine induces contraction and increase in [Ca²⁺]_i in porcine bronchial muscle. However, caffeine suppresses the histamine-induced tension by inhibiting the histamine-induced augmentation of Ca²⁺ sensitivity of the contractile proteins.

Fifty-eight strains of Staphylococcus aureus were isolated from saliva and dental plaques of 66 healthy students and staff members of Iwate Medical University. The coagulase types, and productions of hemolysin, staphylococcal enterotoxins, toxic shock syndrome toxin-1, and β-lactamase, and susceptibility to 22 antimicrobial agents were investigated using these strains.

S. aureus was isolated from the saliva of 68.1% of the 66 subjects and from dental plaque of 19.6%. Types Ⅶ coagulase was predominant (25.8%). Both α and δ types of hemolysin were produced in 100% of the isolates. Staphylococcal enterotoxins were produced in 39.6% of the 58 strains, and type A was predominant. Penicillinase was produced in 75.8%. In the susceptibility test, the isolated strains were resistant to AMPC, CP, CZX, EM, RKM and PCG, whose minimum inhibitory concentrations were ≧ 16μg/ml.

The distribution of lymphatic vessels are clinically very important for the understanding of the route of cancer metastasis. However, the pattern of lymphatic distributions in the muscular bundles of the tongue is unknown. Lymphatics in tongues of the golden hamster, mouse and rat were observed by light microscopy using 5’-Nase staining. The tongue was divided into three sections; the tip, the body and the root. There were three routes of lymphatics in the tongue, namely, a concomitant collecting lymphatic running concomitantly with the deep lingual artery of the tongue, a collecting lymphatic in the septum of the tongue and a collecting lymphatic running to the oral floor along the genioglossus muscle bundles. The distribution of lymphatics in the tongue was basically the same in the golden hamster, mouse and rat. However, the distribution of collecting lymphatics in the lingual septum was less developed in the mouse and rat whose transverse muscles of the tongue were poorly developed. From clinicopathological studies of human tongue cancer, it is presumed that there is the same distribution of lymphatics in human tongue as in rodents’.