Luminal epithelial cells within the mammary gland can produce basal cells upon oncogenic stress.

In the normal mammary gland, the basal epithelium is known to be bipotent and can generate either basal or luminal cells, whereas the luminal epithelium has not been demonstrated to contribute to the basal compartment in an intact and normally developed mammary gland. It is not clear whether cellular heterogeneity within a breast tumor results from transformation of bipotent basal cells or from transformation and subsequent basal conversion of the more differentiated luminal cells. Here we used a retroviral vector to express an oncogene specifically in a small number of the mammary luminal epithelial cells and tested their potential to produce basal cells during tumorigenesis. This in-vivo lineage-tracing work demonstrates that luminal cells are capable of producing basal cells on activation of either polyoma middle T antigen or ErbB2 signaling. These findings reveal the plasticity of the luminal compartment during tumorigenesis and provide an explanation for cellular heterogeneity within a cancer.

The effect of a clinical posting in psychiatry on the attitudes of medical students towards psychiatry and mental illness in a Malaysian medical school.

INTRODUCTION: The stigma attached to mental illness and the mentally ill is a universal phenomenon and a major barrier to the provision of mental health services. Stigmatising attitudes among doctors themselves can result in compromised patient care. The aim of this research project is to study the impact of a clinical posting in psychiatry on the attitudes of medical students to mental illness and to psychiatry. This paper reports the results of the first phase of a longitudinal study. MATERIALS AND METHODS: A total of 122 year 4 medical students responded to this study. The Attitudes Towards Mental Illness (AMI) and Attitudes Towards Psychiatry (ATP) questionnaires were administered before and after an 8-week attachment in psychiatry. RESULTS: We found that students had somewhat favourable attitudes towards psychiatry and mental illness at the start of their attachment, with a mean score of 108.34 on ATP (neutral score, 90) and 68.24 on AMI (neutral score, 60). There was a significant increase in the mean scores of both scales following the psychiatric attachment for female students (ATP: P = 0.003; AMI: P <0.0005), but not male students (ATP: P = 0.435; AMI: P = 0.283). CONCLUSIONS: An 8-week clinical posting of fourth-year medical students in psychiatry was associated with an increase in positive attitudes to mental illness and to psychiatry among female students but not among male students.

Does clinical exposure to patients in medical school affect trainee doctors' attitudes towards mental disorders and patients?--A pilot study.

Stigmatising attitudes towards mental illness may improve with clinical exposure during medical school training. Attitudes of 48 fourth year medical students in Universiti Kebangsaan Malaysia were assessed before and after their compulsory attachment in Psychiatry, using the Attitude Towards Psychiatry-30 (ATP) and the Attitude towards Mental Illness (AMI) questionnaires. ATP scores improved significantly with training (104.8 and 114.4, pre- and post-attachment respectively) as did AMI scores (63.4 and 68.1 respectively). Both improvements were statistically significant. (ATP: z = 4.55, p < 0.0005) (AMI: z = 3.75, p < 0.0005). Attitudes towards mental illness appeared to have become more favourable with clinical training in psychiatry.

Evaluation of genetic damage in operating room personnel exposed to anaesthetic gases.

Information on potential genetic damage in humans after exposure to waste anaesthetic gases in Indian hospitals is scarce. To evaluate the possible genotoxic effects of waste anaesthetic gases, the chromosomal aberrations analysis and comet assay were studied in peripheral blood lymphocytes in 45 operating room personnel currently employed at a hospital in South India. In addition, the micronucleus test on buccal epithelial cells was also carried out in the same subjects. The exposed group was compared with a group of 45 non-exposed group, matched by age, sex, alcohol consumption and smoking habits. The results showed a statistically significant increase in DNA damage by the comet assay in the exposed group. Chromosome aberrations and micronucleus frequencies also increased significantly in the study subjects in comparison to the controls. Analysis of variance showed that smoking had a significant effect on DNA mean tail length, whereas alcohol consumption, duration of exposure to anaesthetic agents, age and gender had no significant effect. All the confounding factors had significant effect by the micronucleus test. However, smoking, alcohol consumption, age, gender and years of exposure showed no significant effect by the chromosome aberrations test. The results of our study suggest that exposure to waste anaesthetic gases has the potential to cause changes in the human genome.