The theoretical prediction power of the software package QikProp was tested. This was achieved by comparing experimentally known results to predicted values. First, simple molecular descriptors for physicochemical properties: octanol -water partition (log P), water solubility (log S), dipole moment, Ionisation Potential (IP) and Electron Affinity (EA) were compared to their experimentally determined counterparts. For all of the descriptors, except EA, a relatively good linear correlation was obtained. Experimentally derived EA values are relatively scarce and often quite inconsistent, which made it difficult to construct a reliable test collection. When compared to values calculated by the Density Functional Theory (DFT) method a reasonable correlation was observed but there is much room for improvement. A clear Gaussian distribution pattern was obtained when a collection of $ 470 marketed orally bioavailable drug compounds was used to generate the physicochemical properties investigated. The idea was explored whether the prediction power of ADME modules could be tested in a qualitative way, based on broad assumptions, using different classes of marketed drug compounds. It was found that this approach gives one a good idea about which modules deserve further attention for evaluation. In this way it is concluded that cell permeation and the blood -brain barrier modules merit more evaluation work whereas work on the HERG K þ and CNS activity modules was discontinued.

BackgroundIrritable bowel syndrome (IBS) and its association with stress, has not been studied among university students in Pakistan. We investigated the prevalence and the pattern of anxiety related IBS symptoms among medical students of Karachi.FindingsAn observational case–control study was carried out at three medical colleges of Karachi, Pakistan. Random sampling was done on 360 medical students. Data was collected using validated tools “Rome III Criteria” and “Generalized Anxiety Disorder Questionnaire”. Participants with IBS were diagnosed on the criteria having experienced abdominal discomfort at least 2–3 days/month associated with high level of anxiety. The apparent prevalence of IBS was found to be 28.3%, with a predominance of 87 (85.29%) females (85.29%) over males (14.71%). The psychological symptoms of anxiety were encountered in 57 (55.8%) participants with IBS, among which males were 15.7% and females 84.2% respectively.ConclusionStudents who more frequently suffer with mental stress and anxiety are more associated with IBS.

Lymphoid cells in most patients with chronic lymphocytic leukemia (CLL), when treated with rituximab, become CD20 ؊ . This is thought to be due to masking of CD20 by rituximab. We used specific antimouse immunoglobulin antibodies to detect rituximab on the surface of CLL lymphocytes and we demonstrate that rituximab is rarely detectable after therapy. Only 3 of 65 patients with CLL had rituximab detectable on their lymphocytes after rituximab therapy despite the fact that most had no detectable CD20 expression. In vitro mixing of CLL or Raji cells with rituximab demonstrated that rituximab was detectable on the surface of cells due to its binding to CD20. However, the addition of plasma led to the down-modulation of CD20 expression, and the rituximab became undetectable. This down-modulation of CD20 protein expression was associated with a downmodulation of CD20 mRNA. CLL cells that lost their CD20 expression regained CD20 expression after 24 hours in culture. These data suggest that rituximab therapy leads to a substantial but transient downmodulation of CD20 expression and that negativity for CD20 in cells from patients treated with rituximab is not necessarily due to CD20 masking.

BackgroundTo assess the incidence of high-risk population of medical students with eating disorders in Karachi by using validated self-administered questionnaires. The earlier these disorders are diagnosed and assessed, the better the chances are for enhanced treatment and fuller recovery. Therefore, we intended to undertake a study to find out the frequency of such disorders among medical students of Karachi and design strategies to overcome them.FindingsA descriptive cross sectional study was conducted in 435 medical students of Karachi. Data was collected using 2 self administered questionnaires, the SCOFF Eating Disorders Questionnaire and the Eating Attitudes Test (EAT-26). Subjects' body mass indexes (BMI) were also calculated. The data was sorted and analyzed in SPSS version 16. According to EAT-26, 22.75% individuals were found to be at high-risk of eating disorders, with 87.9% females and 12.1% males. However, according to SCOFF questionnaire, 17% individuals were found to be at high-risk, with 78.4% females and 21.6% males. According to BMI calculation, 9% were severely underweight, 41.4% underweight, 41.1% normal, 7.6% overweight and 0.9% belonged to obese class 1.ConclusionsA significant fraction of medical students in Karachi are at high risk of development of eating disorders, females being more prone than males. Strategies should be designed to prevent occurrence of such disorders among medical students that would undoubtedly hamper the availability of dependable medical services in future.