Effect of Particle Size of IntratracheallyInstilled Crystalline Silica on Pulmonary Inflammation: Takayoshi KAJIWARA, et al. Department of Environmental Health Engineering, University of Occupational and Environmental HealthCrystalline silica, known as a causal substance of silicosis, has been carefully evaluated for its carcinogenicity and fibrogenicity. In this study, we instilled crystalline silica of two different size (S 1.8 :1.80 µm (S.D. 2.0), S 0.7 :0.74 µm (S.D. 1.5)) into the trachea of rats to evaluate the size effects of the particles on pulmonary inflammation. S 1.8 and S 0.7 samples were administered to rats by a single intratracheal instillation (2 mg/ 0.4 ml saline). At three days, 1 wk and 1, 3 and 6 m o n t h s a f t e r t h e i n s t i l l a t i o n , t h e b l o o d , bronchoalveolar lavage fluid (BALF), and pulmonary tissues were analyzed. Six images per HE-stained section were digitally captured and examined by the point counting method (PCM). Polymorphonuclear leukocyte (PMN)-in-blood specimens and cytospin s p e c i m e n s f r o m B A L F w e r e s t a i n e d immunohistochemically with BrdU. At six months after the instillation, the effects on inflammatory cells in the pulmonary tissues and BALF tended to be more marked in the rats instilled with S 1.8 than those instilled with S 0.7 . Particularly, clear differences were observed in the number of inflammatory cells in BALF. Even if the particles are of the same chemical composition, the results suggest that, their biological effects vary depending on their particle size. Therefore, when such particles are used in workplaces, strict control systems should be established according to the risks present by different sizes of particles.(J Occup Health 2007; 49: [88][89][90][91][92][93][94]

We evaluate the morphometric point counting method (PCM) for qualitatively analyzing pulmonary inflammation and collagen deposits (i.e., fibrosis) in the assessment of the biological hazards of inhaled respirable particles at a realistic dose comparable to that of exposure in the work environment. Rats were exposed by intratracheal instillation to a 2-mg dose, which is close to the estimated overdose at which macrophage clearance is impared, of each of 3 kinds of particulate matter: crystalline silica, crocidolite asbestos, and titanium dioxide. The lung tissue was evaluated at 3 days, 1 wk, and 1, 3, and 6 mo after exposure. Digital images taken of the lung tissue after processing and staining of the lung sections were examined by the PCM under light microscopy. Evidence of inflammation along with progressive inflammatory changes occurred with crystalline silica and crocidolite, which are well-known hazardous particle types. In contrast, lung tissue from rats exposed to titanium dioxide particles demonstrated a decreasing pattern of histopathological change with increasing retention time. Differences in repair patterns of TiO(2) versus crocidolite and silica following the 2-mg dose exposure suggest that the PCM scoring system may be a useful and sensitive tool for qualitatively evaluating the biological hazards of new particle types, for which no toxicological information exists for low-dose exposure, by using the results from assessment of fibrogenic particle types (such as crocidolite and crystalline silica) as well as particle types with low toxicity (such as TiO(2)) as reference points.

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Background: Skeletal-related events due to spinal metastasis in cancer significantly impair patients’ activities of daily living and quality of life. Most of these events occur suddenly. To reduce their impairment occurred suddenly, and to allow them to return to their normal life immediately, many patients undergo palliative surgery; however, some patients do not improve their performance status (PS) as expected. There is little evidence regarding the factors influencing a patient’s PS after palliative surgery. We aimed to investigate the pre-operative predictors of poor PS 1 month after surgery.Methods: The study included a consecutive series of 71 patients with pathological spinal fracture who underwent palliative surgery. Pre-operative predictors of poor post-operative PS were investigated. The participants were categorized into two groups according to PS; the Good group (PS 0, 1, or 2) and the Poor group (PS 3 or 4). We performed univariate and multivariable logistic regression analyses on demographic information, unidentified primary site, AIS grade, poor PS, spinal instability neoplastic score, revised Tokuhashi score, New Katagiri score, modified Glasgow Prognostic Score (mGPS), neutrophil-lymphocyte ratio(NLR), and prognostic nutrition index (PNI). Results: Post-operatively, the Poor group included 38.0% of the patients. Univariate analysis revealed that the following pre-operative factors were related to poor outcomes (p<0.05): BMI<18.5; AIS grade C; poor PS; revised Tokuhashi score 0−8; New Katagiri score 7−10; mGPS 2; and PNI. In the multivariate analysis, mGPS 2 (OR = 22.8, 95% CI = 2.59−202.00, p<0.01) was a significant pre-operative predictor of poor post-operative PS. Conclusion: mGPS 2 was a predictive clinical factor that influenced PS 1 month after surgery. Patients with mGPS 2 should be carefully evaluated to determine their treatment, especially whether they should undergo palliative surgery.