Chemical genetics of \u3ci\u3ePlasmodium falciparum\u3c/i\u3e

Malaria caused by Plasmodium falciparum is a disease that is responsible for 880,000 deaths per year worldwide. Vaccine development has proved difficult and resistance has emerged for most antimalarial drugs. To discover new antimalarial chemotypes, we have used a phenotypic forward chemical genetic approach to assay 309,474 chemicals. Here we disclose structures and biological activity of the entire library—many of which showed potent in vitro activity against drug-resistant P. falciparum strains—and detailed profiling of 172 representative candidates. A reverse chemical genetic study identified 19 new inhibitors of 4 validated drug targets and 15 novel binders among 61 malarial proteins. Phylochemogenetic profiling in several organisms revealed similarities between Toxoplasma gondii and mammalian cell lines and dissimilarities between P. falciparum and related protozoans. One exemplar compound displayed efficacy in a murine model. Our findings provide the scientific community with new starting points for malaria drug discovery

Ameliorating effect of olive oil on fertility of male rats fed on genetically modified soya bean

Background: Genetically modified soya bean (GMSB) is a commercialized food. It has been shown to have adverse effects on fertility in animal trials. Extra virgin olive oil (EVOO) has many beneficial effects including anti-oxidant properties. The aim of this study is to elucidate if addition of EVOO ameliorates the adverse effects on reproductive organs of rats fed on GMSB containing diet. Methods: Forty adult male albino rats (150–180 g) of Sprague Dawley strain were separated into four groups of 10 rats each: Group 1 – control group fed on basal ration, Group 2 – fed on basal ration mixed with EVOO (30%), Group 3 – fed on basal ration mixed with GMSB (15%), and Group 4 – fed on basal ration mixed with GMSB (15%) and EVOO (30%). This feeding regimen was administered for 65 days. Blood samples were collected to analyze serum zinc, vitamin E, and testosterone levels. Histopathological and weight changes in sex organs were evaluated. Results: GMSB diet reduced weight of testis (0.66±0.06 vs. 1.7±0.06, p<0.001), epididymis (0.489±0.03 vs. 0.7±0.03, p<0.001), prostate (0.04±0.009 vs. 0.68±0.04, p<0.001), and seminal vesicles (0.057±0.01 vs. 0.8±0.04, p<0.001). GMSB diet adversely affected sperm count (406±7.1 vs. 610±7.8, p<0.001), motility (p<0.001), and abnormality (p<0.001). GMSB diet also reduced serum zinc (p<0.05), vitamin E (p<0.05), and testosterone (p<0.05) concentrations. EVOO diet had no detrimental effect. Addition of EVOO to GMSB diet increased the serum zinc (p<0.05), vitamin E (p<0.05), and testosterone (p<0.05) levels and also restored the weights of testis (1.35±0.16 vs. 0.66±0.06, p<0.01), epididymis (0.614±0.13 vs. 0.489±0.03, p<0.001), prostate (0.291±0.09 vs. 0.04±0.009, p<0.001), seminal vesicle (0.516±0.18 vs. 0.057±0.01, p<0.001) along with sperm count (516±3.1 vs. 406±7.1, p<0.01), motility (p<0.01), and abnormality (p<0.05). Conclusion: EVOO ameliorates the adverse effects of GMSB on reproductive organs in adult male albino rats. This protective action of EVOO justifies its use against the oxidative damage induced by GMSB in reproductive organs

Discovery of small molecule inhibitors of the interaction of the thyroid hormone receptor with transcriptional coregulators

Thyroid hormone (3,5,3′-triiodo-l-thyronine, T3) is an endocrine hormone that exerts homeostatic regulation of basal metabolic rate, heart rate and contractility, fat deposition, and other phenomena (1, 2). T3 binds to the thyroid hormone receptors (TRs) and controls their regulation of transcription of target genes. The binding of TRs to thyroid hormone induces a conformational change in TRs that regulates the composition of the transcriptional regulatory complex. Recruitment of the correct coregulators (CoR) is important for successful gene regulation. In principle, inhibition of the TR-CoR interaction can have a direct influence on gene transcription in the presence of thyroid hormones. Herein we report a high throughput screen for small molecules capable of inhibiting TR coactivator interactions. One class of inhibitors identified in this screen was aromatic β-aminoketones, which exhibited IC50 values of ∼2 μm. These compounds can undergo a deamination, generating unsaturated ketones capable of reacting with nucleophilic amino acids. Several experiments confirm the hypothesis that these inhibitors are covalently bound to TR. Optimization of these compounds produced leads that inhibited the TR-CoR interaction in vitro with potency of ∼0.6 μm and thyroid signaling in cellular systems. These are the first small molecules irreversibly inhibiting the coactivator binding of a nuclear receptor and suppressing its transcriptional activity

Student assistantship programme: an evaluation of impact on readiness to transit from medical student to junior doctor.

BACKGROUND: Studies report that medical graduates are not prepared for practice as expected, and interventions have been developed to prepare them for practice. One such intervention is the assistantship, which provides hands-on opportunities to hone clinical skills and undertake responsibilities under supervision. The Lee Kong Chian School of Medicine (LKCMed) is Singapore's newest medical school, and students undergo a Student Assistantship Programme (SAP) to prepare for practice as junior doctors (PGY1). This study evaluated the SAP from the students' and clinical supervisors' perspectives. METHODS: Students completed online questionnaires to assess readiness for practice before and after SAP, and a subsample were interviewed about their experiences of SAP and its impact on their preparedness for PGY1. In addition, after our graduates had begun work as PGY1 doctors, their clinical supervisors completed an online questionnaire and were interviewed about the perceived benefits of SAP and the attributes of our graduates as junior doctors. RESULTS: Fifty (96%) students completed the pre-SAP questionnaire and 46 (92%) completed the post-SAP questionnaire. Levels of preparedness increased post-SAP (mean scores range pre-SAP: 2.38 to 4.32 vs post-SAP: 3.08 to 4.48); so did opportunities to undertake PGY1 duties (pre-SAP: 56% vs post-SAP: 96%), and hands-on experience in medical emergencies (pre-SAP: 76% vs post-SAP: 89%).Experience of acute care situations increased except "paracetamol overdose". Readiness to be first respondents in ten acute situations improved (statistically significant for asthma, chronic obstructive pulmonary disease exacerbation, gastrointestinal bleed, sepsis, and adverse drug reactions). Three themes emerged from twenty-five student interviews: learning about the work environment, opportunities to learn in a safe environment, and enhancing SAP for future students. Thirty-three supervisors completed the questionnaire, and 70% rated SAP positively in preparing students for PGY1. Eight supervisors interviewed shared positively about the content, timing, and duration of SAP; and suggested future SAPs help students to develop coping and reflective skills. CONCLUSIONS: The SAP improved students' preparedness and experience across clinical areas, and students felt the SAP helped bridge undergraduate curriculum and work, provided opportunities to hone their skills and learn from junior doctors. Most clinical supervisors rated the SAP effective in preparing students for PGY1. This is the first formal evaluation of an assistantship in Singapore, and the findings are encouraging from the perspective of students and PGY1 supervisors

Role of social comparison in preparedness for practice as a junior doctor in Singapore: a longitudinal qualitative study

ObjectivesTo date, most research on medical graduates’ preparedness for practice has conceptualised preparedness as something possessed by the individual. However, new doctors work within social settings with other people and, given this, we argue that preparedness has a social and comparative dimension. The aim of this paper is to explore medical students’/graduates’ self-assessments of their preparedness for practice using the lens of social comparison theory.SettingWe invited medical students from one of Singapore’s three medical schools who were in their final-year Student Assistantship Programme to participate in semi-structured interviews, and follow-up interviews 6 months later when they were working as junior doctors. Data was collected from two cohorts, in 2018 and 2019. Initial analysis of interview transcripts was inductive and thematic. Social comparison theory was used for subsequent theory-driven analysis.Participants31 participants took part, of whom 21 also engaged in follow-up interviews.ResultsWe identified three uses of social comparison: as coping strategy to manage uncertainties in transitions where there was no formal, objective testing of their performance; as a means to confirm their self-perceived preparedness (upwards or downwards, eg, being better or worse prepared than comparator others); and as the basis for decision-making (eg, changing career choices).ConclusionsSenior medical students and newly-graduated doctors compare themselves with peers and near-peers in terms of prior learning and current performance to evaluate and understand their own performance at work. Future studies need to examine further how the feeling of preparedness or unpreparedness generated from social comparisons may affect subsequent clinical performance and professional development.</jats:sec

A prospective multicentre study evaluating the outcomes of the abdominal wall dehiscence repair using posterior component separation with transversus abdominis muscle release reinforced by a retro-muscular mesh: filling a step

Background This study aimed to evaluate the results of posterior component separation (CS) and transversus abdominis muscle release (TAR) with retro-muscular mesh reinforcement in patients with primary abdominal wall dehiscence (AWD). The secondary aims were to detect the incidence of postoperative surgical site occurrence and risk factors of incisional hernia (IH) development following AWD repair with posterior CS with TAR reinforced by retromuscular mesh. Methods Between June 2014 and April 2018, 202 patients with grade IA primary AWD (Björck’s first classification) following midline laparotomies were treated using posterior CS with TAR release reinforced by a retro-muscular mesh in a prospective multicenter cohort study. Results The mean age was 42 ± 10 years, with female predominance (59.9%). The mean time from index surgery (midline laparotomy) to primary AWD was 7 ± 3 days. The mean vertical length of primary AWD was 16 ± 2 cm. The median time from primary AWD occurrence to posterior CS + TAR surgery was 3 ± 1 days. The mean operative time of posterior CS + TAR was 95 ± 12 min. No recurrent AWD occurred. Surgical site infections (SSI), seroma, hematoma, IH, and infected mesh occurred in 7.9%, 12.4%, 2%, 8.9%, and 3%, respectively. Mortality was reported in 2.5%. Old age, male gender, smoking, albumin level &lt; 3.5 gm%, time from AWD to posterior CS + TAR surgery, SSI, ileus, and infected mesh were significantly higher in IH. IH rate was 0.5% and 8.9% at two and three years, respectively. In multivariate logistic regression analyses, the predictors of IH were time from AWD till posterior CS + TAR surgical intervention, ileus, SSI, and infected mesh. Conclusion Posterior CS with TAR reinforced by retro-muscular mesh insertion resulted in no AWD recurrence, low IH rates, and low mortality of 2.5%. Trial registration Clinical trial: NCT05278117

Metabolic activation of CaMKII by coenzyme A

Active metabolism regulates oocyte cell death via calcium/calmodulin-dependent protein kinase II (CaMKII)-mediated phosphorylation of caspase-2, but the link between metabolic activity and CaMKII is poorly understood. Here we identify coenzyme A (CoA) as the key metabolic signal that inhibits Xenopus laevis oocyte apoptosis by directly activating CaMKII. We found that CoA directly binds to the CaMKII regulatory domain in the absence of Ca(2+) to activate CaMKII in a calmodulin-dependent manner. Furthermore, we show that CoA inhibits apoptosis not only in X. laevis oocytes but also in Murine oocytes. These findings uncover a direct mechanism of CaMKII regulation by metabolism and further highlight the importance of metabolism in preserving oocyte viability

A High-Throughput Screen Indicates Gemcitabine and JAK Inhibitors May be Useful for Treating Pediatric AML

Improvement in survival has been achieved for children and adolescents with AML but is largely attributed to enhanced supportive care as opposed to the development of better treatment regimens. High risk subtypes continue to have poor outcomes with event free survival rates \u3c 40% despite the use of high intensity chemotherapy in combination with hematopoietic stem cell transplant. Here we combine high-throughput screening, intracellular accumulation assays, and in vivo efficacy studies to identify therapeutic strategies for pediatric AML. We report therapeutics not currently used to treat AML, gemcitabine and cabazitaxel, have broad anti-leukemic activity across subtypes and are more effective relative to the AML standard of care, cytarabine, both in vitro and in vivo. JAK inhibitors are selective for acute megakaryoblastic leukemia and significantly prolong survival in multiple preclinical models. Our approach provides advances in the development of treatment strategies for pediatric AML