Oncogenes expand during evolution to withstand somatic amplification.

Background: Cancer-related genes are under intense evolutionary pressure. We conjectured that gene size is an important determinant of amplification propensity for oncogenes and thus cancer susceptibility and therefore could be subject to natural selection. Patients and methods: Gene information, including size and genomic locations, of all protein-coding genes were downloaded from Ensembl (release 87). Quantification of gene amplification was based on Genomic Identification of Significant Targets in Cancer scores obtained from available The Cancer Genome Atlas studies. Results: Oncogenes are larger in size as compared with non-cancer genes (mean size: 92.1 kb versus 61.4 kb; P < 0.0001) in the human genome, which is contributed by both increased total exon size (mean size: 4.6 kb versus 3.4 kb; P < 0.0001) and higher intronic content (mean %: 84.8 versus 78.0; P < 0.01). Such non-random size distribution and intronic composition are conserved in mouse and Drosophila (all P < 0.0001). Stratification by gene age indicated that young oncogenes have been subject to a stronger evolutionary pressure for gene expansion than their non-cancer counterparts. Pan-cancer analysis demonstrated that larger oncogenes were amplified to a lesser extent. Tumor-suppressor genes also moved toward small oncogenes in the course of evolution. Conclusions: Oncogenes expand in size whereas tumor-suppressor genes move closer to small oncogenes in the course of evolution to withstand oncogenic somatic amplification. Our findings have shed new light on the previously unappreciated influence of gene size on oncogene amplification and elucidated how cancers have shaped our genome to its present configuration.

A study on job satisfaction among clinical and non-clinical hospital staff in a teaching hospital in Lagos, Nigeria.

OBJECTIVES: Previous studies had demonstrated that continuous and effective productivity of hospital staff are linked to job satisfaction and only those who are satisfied with their job can be maximally effective and productive. This cross-sectional descriptive survey was designed to determine the levels of job satisfaction among various groups of health care professionals working in a teaching hospital in Lagos, Nigeria. METHODS: Two hundred clinical and non-clinical hospital staff were invited to take part in the study. They completed a sociodemographic questionnaire and the Job Descriptive Index (JDI). RESULTS: The results indicated that majority clinical and non-clinical staff were satisfied with their jobs as regards the parameters of the JDI compared with those not satisfied with their jobs. CONCLUSION: The government and health policy makers should continue to pay attention to boost job morale and satisfaction of medical health workers to continue to make them to be satisfied with their job.

Assessment of fetal biparietal diameter during normal pregnancy by ultrasound in Nigerian women.

The fetal biparietal diameter (BPD) was measured on 1104 occasions in 552 Nigerian women during normal pregnancy, and the range of BPD values for each week of pregnancy between 12 and 40 weeks was determined. Growth of the BPD in our population showed an asymptotic curve like that of Europeans but our values were slightly higher. The mean weekly increase in the BPD between 13 and 30 weeks gestation was 4.9 mm/week, between 30 and 36 weeks, 3.3 mm/week and between 37 and 40 weeks, 1.7 mm/week. But there was no significant difference between the BPD measurements of Europeans and Nigerian fetuses except towards term.

Prevalence of hyperprolactinaemia and galactorrhoea in secondary amenorrhoea.

Using Commercial R.I.A. Kits, plasma prolactin levels have been assayed in 41 Nigerian women with secondary amenorrhoea and in 10 normal ovulating women. The prolactin levels were 34.5 +/- 28.9 ng/ml and 14 +/- 6.8 ng/ml respectively; these prolactin levels differed significantly (p less than 0.001). Fifteen amenorrhoeic women had prolactin levels exceeding 28 ng/ml while no normal women had such prolactin levels. The highest prolactin levels, greater than 100 ng/ml were in the two patients with pituitary tumours. The relative frequency of galactorrhoea in patients with secondary amenorrhoea was 19.5%. The results of this study are comparable with those obtained in Caucasians.