Kiyoshi Ishida

Endothelin-1 stimulates arachidonate 15-lipoxygenase activity and oxygen radical formation in the rat distal lung

We investigated the effects of intravenous bolus of endothelin-1 on the metabolism of eicosanoids and oxygen radicals in the distal lung unit of the rat. Intravenous bolus of endothelin-1 caused a significant increase in 15-hydroxyeicosatetraenoic acid of bronchoalveolar lavage fluid and oxygen radicals produced by the bronchoalveolar cells. Endothelin-1 exhibited a stimulatory effect on the 15-lipoxygenase activity in the lung homogenate. Thus, endothelin-1 may contribute to the inflammatory and hyperreactive process of lungs, by enhancing the release of 15-hydroxyeicosatetraenoic acid and oxygen radicals in the distal lung unit.

The effects of aging on the function of alveolar macrophages in mice.

In order to determine whether the function of alveolar macrophages (AM) is modulated by aging, we measured the TNF-alpha production, phagocytic function, and surface antigen expression of AM from young and old mice. When AM were primed by IFN-gamma (500 units/ml) and triggered by LPS (100 micrograms/ml), TNF-alpha production by AM was significantly smaller in old mice as compared with young mice (young mice: 161.7 +/- 28.2 units/ml; old mice: 89.3 +/- 13.6 units/ml, P < 0.05). The percentage of AM which phagocytosed latex particles (more than one particle) in old mice was significantly lower than in young mice (young: 78.1 +/- 2.5%; old: 62.8 +/- 3.4%, P < 0.05). Ia antigen expression of the AM was significantly higher and asialo-GM1 antigen expression was significantly lower in old mice than in young mice (Ia: young, 0.030 +/- 0.005; old, 0.092 +/- 0.024, P < 0.05; asialo-GM1: young, 0.-9 +/- 0.01; old, 0.75 +/- 0.07, P < 0.01). These results suggest that alveolar macrophage function is at least decreased in part with aging in mice.

Inhibition of Mouse Alveolar Macrophage Production of Tumor Necrosis Factor Alpha by Acute in vivo and in vitro Exposure to Tobacco Smoke

We investigated the effects of tobacco smoke exposure on the production of tumor necrosis factor alpha (TNF alpha) by alveolar macrophages (AM) in mice (C57BL/6). The results obtained are as follows: (1) In vivo tobacco smoke exposure caused a significant decrease in the production of TNF alpha by AM with the stimulation of lipopolysaccharide (LPS; control group: 19.32 +/- 5.52 U/ml, smoked group: 4.28 +/- 0.98 U/ml; p less than 0.05). (2) In vitro exposure of AM to tobacco smoke extracts (water-soluble extracts) also caused a decrease in the production of TNF alpha up to 93% of control with stimulation of LPS (p less than 0.05) without any decrease in cellular viability. We concluded that the production of TNF alpha by AM was impaired by smoking via direct action of the factors present in tobacco smoke.

Effect of chronic tobacco smoke exposure on the function of alveolar macrophages in mice.

We evaluated the effect of chronic tobacco smoke exposure on the function of the alveolar macrophage (AM) in mice. Tumor necrosis factor-alpha production of the AM triggered by lipopolysaccharides was smaller in smoke-exposed mice as compared to control mice but did not reach statistical significance (27.3 +/- 4.0 vs. 34.8 +/- 4.9 U/ml). The percentage of AM which did not phagocytize latex particles in the smoke-exposed mice was significantly larger than that in control mice (33.9 +/- 2.3 vs. 20.8 +/- 2.1%; p < 0.05). Ia antigen expression of the AM was significantly larger in smoke-exposed mice (cytotoxicity index: 0.180 +/- 0.033 vs. 0.038 +/- 0.0118; p < 0.01). The asialo-GM1 antigen expression was similar in both groups (0.949 +/- 0.007 vs. 0.961 +/- 0.011). Although the precise mechanisms of these functional changes of the AM by tobacco smoke exposure are not clear, they may have some immunological effects on the alveolar space.

Intravenous bolus of prednisolone decreases 15-hydroxyeicosatetraenoic acid formation in the rat model of acid aspiration

Background and MethodsTo test the hypothesis that the effect of steroids on hydrochloric acid aspiration may be involved in the metabolism of eicosanoids, we investigated the effects of an iv bolus of prednisolone on the metabolism of 15-hydroxyeicosatetraenoic acid and 11-dehydrothromboxane B2 (11-dehydro-TxB2) in the rat model of acid aspiration. Wistar rats were randomly selected for three groups and treated with either a) an iv bolus of saline after intratracheal injection of saline (control group), b) an iv bolus of saline after intratracheal injection of acid (acid-saline group), or c) an iv bolus of prednisolone after intratracheal injection of acid (acid-prednisolone group). The concentrations of 15-hydroxyeicosatetraenoic acid and 11-dehydro-TxB2 in bronchoalveolar lavage fluid were measured by radioimmunoassay. ResultsThe concentration of 15-hydroxyeicosatetraenoic acid in bronchoalveolar lavage fluid of either acid-saline group (804 ± 129 pg/ mL) or acid-prednisolone group (748 ± 112 pg/ mL) was significantly greater than that of the control group (143 ± 27 pg/mL, p < .01) 1 hr after the administration. The iv bolus of prednisolone caused a significant decrease in 15-hydroxyeicosatetraenoic acid (acid-saline group 1027 ± 43 pg/mL; acid-prednisolone group 514 ± 62 pg/mL; p < .01) and cell counts of bronchoalveolar lavage fluid 48 hrs after intratracheal injection of acid, while there was no significant change in 11-dehydro-TxB2. ConclusionThese findings suggest that corticosteroid administration may contribute to the inhibition of the inflammatory process of lungs after acid aspiration by decreasing the release of 15-hydroxyeicosatetraenoic acid in the distal lung unit. (Crit Care Med 1991; 19:950)

Efficacy of Oral Administration of Ofloxacin in Lower Respiratory Tract Infections in Aged Patients with Chronic Lung Disease

The efficacy of ofloxacin for the treatment of lower respiratory tract infection was evaluated in aged patients with chronic lung disease. Results are the following: improvement of leukocytosis and arterial oxygen tension was observed; peripheral blood cell analysis showed a decrease in natural killer cell counts and in helper/suppressor T cell ratio; superoxide production by peripheral blood white cells was decreased after treatment; interleukin-2 production was rather increased. We concluded that improvement in the immunological parameters indicated the efficacy of ofloxacin for lower respiratory tract infection in aged patients with chronic lung disease.

Influence of Age on Ventilatory Pattern during Exercise

Previous investigators have reported that exercise capacity is decreased in the elderly with the reduction in maximal oxygen uptake1). We have previously demonstrated that healthy elderly achieve greater V-E/V-O2 for a given exercise load than the young during exercise2). However, the pattern of ventilation on exercise has not been extensively evaluated and little is known as to the changes in the fractional contribution of abdomen vs thorax in relation to total ventilation during exercise in old age.