BACKGROUND: Organic chemicals have been known to cause allergic diseases such as bronchial asthma and hypersensitivity pneumonitis; however, the possibility that they do not cause irreversible pulmonary fibrosis has not been considered. Polyacrylic acid (PAA), an organic chemical, has caused irreversible progressive pulmonary fibrosis in exposed workers, indicating its potential to induce pulmonary inflammation and fibrosis. Although intratracheal instillation studies are commonly used for evaluating lung pathology, traditional methods face challenges with chemical substances, particularly nanoparticles, which tend to aggregate in suspension and prevent uniform pulmonary distribution. Such aggregation alters the qualitative and quantitative responses to lung injury, limiting accurate assessment of lung pathology. To overcome this limitation, we developed a 'molecular dispersion method' that uses pH modification to negative charges to PAA particles, maintaining their dispersion. Using this method, we investigated the effects of PAA on pulmonary inflammation and fibrosis in a rat model. METHODS: F344 rats were intratracheally instilled with PAA using molecular dispersion (0.1 mg/rat, 1.0 mg/rat), PAA without molecular dispersion (1.0 mg/rat), and normal saline (control group). Rats were sacrificed at 3 days, 1 week, 1 month, 3 months, and 6 months after exposure to examine inflammatory and fibrotic responses. RESULTS: PAA caused persistent increases in neutrophil influx in the bronchoalveolar lavage fluid (BALF) from 3 days to 1 month following instillation. In histopathological findings, the group with molecular dispersion had almost no inflammatory masses in the lung tissue compared to the group without molecular dispersion, and exhibited relatively uniform dispersion. CONCLUSION Intratracheal instillation of dispersed PAA induced neutrophil inflammation and fibrosis in the rat lung, suggesting that PAA might have pulmonary inflammogenicity and fibrogenicity. Intrapulmonary dispersion of PAA particles following intratracheal instillation studies using the molecular dispersion method was similar to that following inhalation studies.
Animals ; Rats, Inbred F344 ; Acrylic Resins/adverse effects* ; Rats ; Inhalation Exposure/adverse effects* ; Male ; Pulmonary Fibrosis/pathology* ; Pneumonia/pathology* ; Lung/pathology* ; Bronchoalveolar Lavage Fluid/cytology*

Rikkunshito is comprised of 8 crude drugs and is used for the treatment of gastrointestinal dysfunctions such as anorexia and heavy stomach feeling. These symptoms are often caused by delay in gastric emptying. Cisplatin is a representative cancer chemotherapeutic drug with severe adverse effects such as anorexia and nausea, that gives rise to a delay in gastric emptying. However, it is still unknown whether rikkunshito has effects on improving the delayed gastric emptying induced by cisplatin. In the present study, we examined the effects of rikkunshito (an Atractylodis rhizoma-containing formula) on cisplatin-induced delay in gastric emptying in the rat. Rikkunshito improved this. Among the crude drugs that comprise rikkunshito, Atractylodis rhizoma, Ginseng radix, Poria and Aurantii nobilis pericarpium individually improved the delay in gastric emptying, suggesting that they all contribute to the action of rikkunshito. Moreover, the effects of these 4 crude drugs in combinations were also examined, and as a result, tended to be stronger when Atractylodis rhizoma was included. On the other hand, when Atractylodis rhizoma was excluded from rikkunshito, the effects were weaker. Meanwhile, atractylenolide III, a specific chemical constituent of Atractylodis rhizoma, improved delay in gastric emptying in a manner similar to that of rikkunshito with Atractylodis rhizoma. These results, taken together, suggest that Atractylodis rhizoma likely contributes greatly to the improving effect of rikkunshito on cisplatin-induced delay in gastric emptying.

Clinical clerkships have been gradually introduced in medical schools in Japan. Because all students do not rotate through the same departments, the satisfaction of medical students differs among the departments, although the underlying reasons for such differences are unclear. To investigate the factors associated with student satisfaction with clinical clerkships, we performed a questionnaire survey.1) Questionnaires were distributed to 99 fifth-year medical students at Kyoto University Medical School. The questionnaire consisted of Likert-type 5-level scales of satisfaction, clinical clerkship assignments, and the attitudes of clerkship supervisors and other attending staff. Eighty-nine students responded.2) The independent factors for students' satisfaction were the attitude of attending staff (beta coefficient, 0.34), the attitude of the clerkship supervisor (0.30), and the frequency of physical examinations (0.09).3) Twenty-two of the 34 students who expressed the lowest level of satisfaction (level 1) reported that "the attending staff rarely had contact with students."4) Factors not associated with satisfaction were: whether the rotation was in internal medicine or surgery; whether the rotation was in a community hospital or a university hospital, and the department.5) These results suggest that medical students are satisfied with a clerkship if they perform frequent physical examinations and if the attending staff have an enthusiastic attitude.