Investigating the Mechanistic Inhibitory Discrepancies of Novel Halogen and Alkyl Di-Substituted Oxadiazole-Based Dibenzo-Azepine-Dione Derivatives on Poly (ADP-Ribose) Polymerase-1

Numerous studies have established the involvement of Poly (ADP-ribose) Polymerase-1 (PARP-1) in cancer presenting it as an important therapeutic target over recent years. Although homology among the PARP protein family makes selective targeting difficult, two compounds [d11 (0.939 μM) and d21 (0.047 μM)] with disparate inhibitory potencies against PARP-1 were recently identified. In this study, free energy calculations and molecular simulations were used to decipher underlying mechanisms of differential PARP-1 inhibition exhibited by the two compounds. The thermodynamics calculation revealed that compound d21 had a relatively higher ΔG_bind than d11. High involvement of van der Waal and electrostatic effects potentiated the affinity of d21 at PARP-1 active site. More so, incorporated methyl moiety in d11 accounted for steric hindrance which, in turn, prevented complementary interactions of key site residues such as TYR889, MET890, TYR896, TYR907. Conformational studies also revealed that d21 is more stabilized for interactions in the active site compared to d11. We believe that findings from this study would provide an important avenue for the development of selective PARP-1 inhibitors.     

ADAPTATION OF HEMOPOIETIC TISSUE RESULTING FROM ESTRONE-INDUCED OSTEOSCLEROSIS IN MICE

The redistribution of hemopoietic tissue resulting from estrone-induced osteosclerosis in the mouse was studied. As the marrow was gradually replaced by bone, extramedullary hematopoiesis in the spleen increased at a rate sufficient to maintain hemopoietic homeostasis. The total numbers of colony forming units (CFU) in the tibia and spleen as well as the proportion of CFU in cycle was assessed. After five injections of estrone, tibial CFUs decreased to 2% of control values whereas splenic CFUs increased approximately nine-fold. The proliferative capacity of the splenic CFU was also increased in the estrone-treated animals. The increased numbers of splenic CFUs as well as the increased proliferative capacity of this compartment are probably related to the ability of extramedullary hematopoiesis in the spleen to compensate for a marrow that has been replaced by bone.     

Association of Antenatal Depression with Adverse Consequences for the Mother and Newborn in Rural Ghana: Findings from the DON Population-Based Cohort Study

Background

Whilst there is compelling evidence of an almost 2-fold increased risk of still births, and suggestive evidence of increased mortality among offspring of mothers with psychotic disorders, only three studies have addressed the role of antenatal depression (AND) on survival of the baby. We examined these associations in a large cohort of pregnant women in Ghana.

Methods

A Cohort study nested within 4-weekly surveillance of all women of reproductive age to identify pregnancies and collect data on births and deaths in the Kintampo Health Research Centre study area of Ghana. Women were screened for AND using the Patient Health Questionnaire (PHQ-9) to ascertain DSM-IV major or minor depression. Outcomes were adverse birth outcomes, maternal/infant morbidity, and uptake of key newborn care practices, examined using logistic regression; effect sizes reported as relative risks with 95% confidence intervals.

Results

20679 (89.6%) pregnant women completed the PHQ-9. The prevalence of AND was 9.9% (n = 2032) (95% confidence interval 9.4%–10.2%). AND was associated with: prolonged labour (RR 1.25, 95% CI 1.02–1.53); peripartum complications (RR 1.11, 95% CI 1.07–1.15);postpartum complications (RR 1.27, 96% CI 1.21–1.34); non-vaginal delivery (RR 1.19, 95% CI 1.02–1.40); newborn illness (RR 1.52, 95% CI 1.16–1.99); and bed net use during pregnancy (RR 0.93, 95% CI 0.89–0.98), but not neonatal deaths, still births, low birth weight, immediate breast feeding initiation, or exclusive breastfeeding. AND was marginally associated with preterm births (RR 1.32, 95% CI 0.98–1.76).

Conclusion

This paper has contributed important evidence on the role of antenatal depression as a potential contributor to maternal and infant morbidity. Non-pharmacological treatments anchored on primary care delivery structures are recommended as an immediate step. We further recommend that trials are designed to assess if treating antenatal depression in conjunction with improving the quality of obstetric care results in improved maternal and newborn outcomes.     

Insight into the Therapeutic Potential of a Bicyclic Hydroxypyridone Compound 2-[(2,4-Dichlorophenyl)methyl]-7-hydroxy-1,2,3,4-tetrahydro-8H-pyrido[1,2-a]pyrazin-8-one as COMT Inhibitor in the Treatment of Parkinson's Disease: A Molecular Dynamic Simulation Approach

Parkinson's disease (PD) is one of the most targeted neurodegenerative diseases in clinical research. Awareness of research is due to its increasing number of affected people worldwide. The pathology of PD has been linked to several key proteins upregulation such as the catechol O-Methyltransferase (COMT). Hence, the synthesis of compounds possessing inhibitory capacity has been the frontline of research in recent years. Several compounds have been synthesized among which is the nitrocatechol. However, major limitations associated with the nitrocatechol scaffold include the inability to possess adequate CNS penetration properties and hepatic toxicity associated with the compounds. However, a series of bicyclic hydroxypyridones compounds were synthesized to evaluate their inhibitory potentials on COMT protein with compound 38 (c38) 2-[(2,4-dichlorophenyl)methyl]-7-hydroxy-1,2,3,4-tetrahydro-8H-pyrido[1,2-a]pyrazin-8-one shown to have a 40 fold increase level coverage in its IC₅₀ over brain exposure when compared to the other synthesized compound. The molecular dynamics method was employed to understand the nature of interaction exhibited by c38. Molecular mechanics of c38 revealed a disruptive effect on the secondary structure of COMT protein. Per residue decomposition analysis revealed similar crucial residues involved in the favorable binding of c38 and tolcapone implicated its increased inhibitory capacity on COMT in preventing PD. Free binding energy (ΔG_bind) of c38 further revealed the inhibitory capacity towards COMT protein in comparison to the FDA approved tolcapone. Ligand mobility analysis of both compounds showed a timewise different mobility pattern across the simulation time frame at the active site pocket of the protein connoting the different inhibitory potency exhibited by c38 and tolcapone. Findings from this study revealed optimization of c38 could facilitate the discovery of new compounds with enhanced inhibitory properties towards COMT in treating PD.     

Recruiting monomer for dimer formation: resolving the antagonistic mechanisms of novel immune check point inhibitors against Programmed Death Ligand-1 in cancer immunotherapy

The design of small molecule antagonists against Programmed Death Ligand-1 (PD-L1) has been the recent highlight of the immune checkpoint blockade therapy. This interventive approach has been potentiated by the development of BMS compounds; BMS-1001 and BMS-1166, which exert their therapeutic activities by inducing dimerisation of PD-L1; a molecular mechanism that has remained unclear. For the first time, we resolve the dynamical events that underlie the antagonistic mechanisms of BMS-1001 and BMS-1166 when bound to PD-L1 using an all-atom molecular dynamics (MD) simulations approach and free binding energy Molecular Mechanics/Poisson-Boltzmann Surface Area (MM/PBSA) calculations. Time-scale dynamical findings revealed that upon binding a PD-L1 monomer, the BMS-compounds gradually facilitated the ‘inbound’ motion of another PD-L1 monomer in the same conformational phase space up till dimer formation. Moreover, the non-liganded PD-L1 monomer exhibited the highest structural flexibility and atomistic motions relative to the BMS-liganded monomer as revealed by post-MD trajectory analyses using root mean square deviation (RMSD) and root mean square fluctuations (RMSF) parameters. Trajectory investigations into ligand motions also revealed that the BMS compounds exhibited mechanistic transitions from the monomeric binding site (monomer A) where they were initially bound, to the second monomeric site (monomer B) where they were strongly bound, followed by eventual high-affinity interactions at the tunnel-like binding cleft formed upon the dimerisation of both PD-L1 monomers. These findings present a model that describes the mechanism by which the BMS compounds induce PD-L1 dimerisation and could further enhance the design of highly selective and novel monomeric recruiters of PD-L1 in cancer immunotherapy.     

Impact of Free Delivery Care on Health Facility Delivery and Insurance Coverage in Ghana’s Brong Ahafo Region

Background

Many sub-Saharan countries, including Ghana, have introduced policies to provide free medical care to pregnant women. The impact of these policies, particularly on access to health services among the poor, has not been evaluated using rigorous methods, and so the empirical basis for defending these policies is weak. In Ghana, a recent report also cast doubt on the current mechanism of delivering free care – the National Health Insurance Scheme. Longitudinal surveillance data from two randomized controlled trials conducted in the Brong Ahafo Region provided a unique opportunity to assess the impact of Ghana’s policies.

Methods

We used time-series methods to assess the impact of Ghana’s 2005 policy on free delivery care and its 2008 policy on free national health insurance for pregnant women. We estimated their impacts on facility delivery and insurance coverage, and on socioeconomic differentials in these outcomes after controlling for temporal trends and seasonality.

Results

Facility delivery has been increasing significantly over time. The 2005 and 2008 policies were associated with significant jumps in coverage of 2.3% (p = 0.015) and 7.5% (p<0.001), respectively after the policies were introduced. Health insurance coverage also jumped significantly (17.5%, p<0.001) after the 2008 policy. The increases in facility delivery and insurance were greatest among the poorest, leading to a decline in socioeconomic inequality in both outcomes.

Conclusion

Providing free care, particularly through free health insurance, has been effective in increasing facility delivery overall in the Brong Ahafo Region, and especially among the poor. This finding should be considered when evaluating the impact of the National Health Insurance Scheme and in supporting the continuation and expansion of free delivery care.