Comparison of the Accuracy of Age Estimation Methods on Saudi Arabian Population - A Cross Sectional Study

Identity and legal culpability hinges on age estimation in modern society. There are several biometric methods for accurate age determination that have validity in medico-legal proceedings globally. The accuracy of conventional methods should be reassessed periodically to ascertain validity in differing global societies. This study aims to evaluate the comparative accuracy of three age determination methods based on non-invasive radiographic odontometric data when applied to a sample of Saudi population. MethodsThis cross-sectional study is done on 350 subjects of Saudi Arabian population, aged between 4 and 16 years. The same set of radiographs is used in all three methods and the dental age estimation is done by trained examiners who determine the age using Demirjian’s, Willem’s and the London Atlas Method. Statistical analysis is done using the IBM SPSS (Statistical Package for Social Science) software (version 19). Significance of differences between the chronological age and the estimated dental age was calculated using paired ‘t’ test (P value of < 0.05 was considered significant. ResultsThe chronological age was above estimated age by all three methods used to assess male samples. Significant difference was seen with William's method (p=0.000) and the the London Atlas Method (p=0.000), and no significant difference was seen with Demirjian's method (p=0.102). Demirjian's method estimated the age above chronological age for females while the other two methods were below in their estimates. There were significant differences only between the London Atlas estimates and chronological age in females (p = 0.020). ConclusionsAge estimated by Demirjian’s method on Saudi population is most accurate among the methods tested. Boys showed more variations than girls when the ages were measured. Changing diet and socioeconomic factors influence growth and development of children, and this can alter the anticipated outcomes of age determination by mathematical methods.

New mathematical derivations for calculation of ATP yield due to the complete oxidation of different types of fatty acids.

During the complete oxidation of fatty acids, the electrons removed from fatty acids in different forms (FADH2 and NADH2) pass through the respiratory chain, driving the ATP synthesis. Generally, the ATP yield due to the complete oxidation of fatty acids is calculated by sum total the ATPs obtained due to the oxidation of FADH2 and NADH2 due to lack of any particular method. This calculation is simple for saturated even numbered fatty acids, but in the case of saturated and unsaturated odd numbered fatty acids the calculation of ATP yield is difficult and needs mathematical calculations due to some changes in their β-oxidation pathway when compared to the pathway of saturated even numbered fatty acids. These calculations are made simple by our derivations and following formulae where we require only number of carbon atoms and double bonds present in a fatty acid. Our method is superior and easier in comparison to long mathematical calculations that are in the practice.

Risk factors associated with development of ventilator associated pneummonia

To assess the risk factors associated with development of ventilator associated pneumonia [VAP]. A case control study. Intensive Care Unit [ICU] at the Aga Khan University Hospital, Karachi, between January 1999 and June 2000. All patients with assisted mechanical ventilation were assessed for the development of VAP. Risk factors associated with development of VAP were determined. Adult patients who developed pneumonia, 48 hours after ventilation, were called cases while those who did not develop pneumonia were called controls. Seventy [28%] out of 250 mechanically ventilated patients developed VAP [rate of VAP was 26 cases per 1000 ventilator days]. Shock during first 48 hours of ventilation [odds ratio [OR], 5.95; 95% confidence interval [CI], 2.83-12.52], transport out of ICU during mechanical ventilation [OR, 6.0; 95% CI, 2.92-12.37], re-intubation [OR, 4.23; 95% CI, 2.53-9.85], prior episode of aspiration of gastric content [OR, 3.07; 95% CI, 1.35-7.01], and use of antibiotics prior to intubation [OR,2.55; 95% CI, 1.20-5.41] were found to be independently associated with a higher risk of developing VAP. Gram negative organisms and Staphylococcus aureus were responsible for over 90% of cases. Patients with VAP had higher crude mortality rate [57.1%] compared with controls [32.2%]. Ventilator associated pneumonia is associated with a high mortality. This study has identified risk factors associated with VAP