A retrospective review of all bronchoscopy cases for investigation of lung cancer between January 1997 and December 1999 was done. The cases were included if endobronchial mass was visible (Group A) or when there was an abnormal mucosa and/or bronchial narrowing in the absence of a mass (Group B). All patients in Group A (n = 177) underwent endobronchial biopsy (EB) bronchial brushings (BB) and bronchial washings (BW). All cases in Group B underwent transbronchial biopsy (TBB), BB and BW. Only a small increase in the positive results for cancer was seen when cytology specimens (BB and BW) were added to EB (85.3% vs 88.1%, McNemar's P = 0.06) in Group A but there was a significant increase in Group B (37.3% vs 54.2%. McNemar's, P = 0.001). Therefore although cytology specimens did not significantly add to overall yield of positive results when endobronchial lesions were visible, when mass lesions were not visible, cytology specimens increased the yield by 16.9%.
Study site: Chest clinic, Hospital Sultanah Aminah (HSA), Johor Bahru, Johor, Malaysia
This study evaluated human embryonic stem cells (hESC) and their differentiated fibroblastic progenies as cellular models for genotoxicity screening. The DNA damage response of hESCs and their differentiated fibroblastic progenies were compared to a fibroblastic cell line (HEPM, CRL1486) and primary cultures of peripheral blood lymphocytes (PBL), upon exposure to Mitomycin C, gamma irradiation and H2O2. It was demonstrated that hESC-derived fibroblastic progenies (H1F) displayed significantly higher chromosomal aberrations, micronuclei formation and double strand break (DSB) formation, as compared to undifferentiated hESC upon exposure to genotoxic stress. Nevertheless, H1F cell types displayed comparable sensitivities to genotoxic challenge as HEPM and PBL, both of which are representative of somatic cell types commonly used for genotoxicity screening. Subsequently, transcriptomic and pathways analysis identified differential expression of critical genes involved in cell death and DNA damage response upon exposure to gamma irradiation. The results thus demonstrate that hESC-derived fibroblastic progenies are as sensitive as commonly-used somatic cell types for genotoxicity screening. Moreover, hESCs have additional advantages, such as their genetic normality compared to immortalized cell lines, as well as their amenability to scale-up for producing large, standardized quantities of cells for genotoxicity screening on an industrial scale, something which can never be achieved with primary cell cultures.