Evaluation of a diospyrin derivative as antileishmanial agent and potential modulator of ornithine decarboxylase of Leishmania donovani

World health organization has called for academic research and development of new chemotherapeutic strategies to overcome the emerging resistance and side effects exhibited by the drugs currently used against leishmaniasis. Diospyrin, a bis-naphthoquinone isolated from Diospyros montana Roxb., and its semi-synthetic derivatives, were reported for inhibitory activity against protozoan parasites including Leishmania. Presently, we have investigated the antileishmanial effect of a di-epoxide derivative of diospyrin (D17), both in vitro and in vivo. Further, the safety profile of D17 was established by testing its toxicity against normal macrophage cells (IC₅₀ ∼ 20.7 μM), and also against normal BALB/c mice in vivo. The compound showed enhanced activity (IC₅₀ ∼ 7.2 μM) as compared to diospyrin (IC₅₀ ∼ 12.6 μM) against Leishmania donovani promastigotes. Again, D17 was tested on L. donovani BHU1216 isolated from a sodium stibogluconate-unresponsive patient, and exhibited selective inhibition of the intracellular amastigotes (IC₅₀ ∼ 0.18 μM). Also, treatment of infected BALB/c mice with D17 at 2 mg/kg/day reduced the hepatic parasite load by about 38%. Subsequently, computational docking studies were undertaken on selected enzymes of trypanothione metabolism, viz. trypanothione reductase (TryR) and ornithine decarboxylase (ODC), followed by the enzyme kinetics, where D17 demonstrated non-competitive inhibition of the L. donovani ODC, but could not inhibit TryR.     

Size- and Age-Dependent Neurotoxicity of Engineered Metal Nanoparticles in Rats

Earlier we showed that chronic administration of engineered nanoparticles (NPs) from metals, e.g., Cu, Ag, or Al (50–60 nm, 50 mg/kg, i.p. daily for 1 week) alter blood–brain barrier (BBB) disruption and induce brain pathology in adult rats (age 18 to 22 weeks). However, effects of size-dependent neurotoxicity of NPs in vivo are still largely unknown. In present investigation, we examined the effects of different size ranges of the above-engineered NPs on brain pathology in rats. Furthermore, the fact that age is also an important factor in brain pathology was also investigated in our rat model. Our results showed that small-sized NPs induced the most pronounced BBB breakdown (EBA +480 to 680 %; radioiodine +850 to 1025 %), brain edema formation (+4 to 6 %) and neuronal injuries (+30 to 40 %), glial fibrillary acidic protein upregulation (+40 to 56 % increase), and myelin vesiculation (+30 to 35 % damage) in young animals as compared to controls. Interestingly, the oldest animals (30 to 35 weeks of age) also showed massive brain pathology as compared to young adults (18 to 20 weeks old). The Ag and Cu exhibited greater brain damage compared with Al NPs in all age groups regardless of their size. This suggests that apart from the size, the composition of NPs is also important in neurotoxicity. The very young and elderly age groups exhibited greater neurotoxicity to NPs suggests that children and elderly are more vulnerable to NPs-induced brain damage. The NPs-induced brain damage correlated well with the upregulation of neuronal nitric oxide synthase activity in the brain indicating that NPs-induced neurotoxicity may be mediated via increased production of nitric oxide, not reported earlier.     

A Peptide Bond from the Inter-lobe Segment in the Bilobal Lactoferrin Acts as a Preferred Site for Cleavage for Serine Proteases to Generate the Perfect C-lobe: Structure of the Pepsin Hydrolyzed Lactoferrin C-lobe at 2.28 Å Resolution

The Protein Journal - C-lobe represents the C-terminal half of lactoferrin which is a bilobal 80 kDa iron binding glycoprotein. The two lobes are designated as N-lobe (Ser1-Glu333) and...     

Prospective validation of the ABCD2 score for patients in the emergency department with transient ischemic attack

Background:

The ABCD2 score (Age, Blood pressure, Clinical features, Duration of symptoms and Diabetes) is used to identify patients having a transient ischemic attack who are at high risk for imminent stroke. However, despite its widespread implementation, the ABCD2 score has not yet been prospectively validated. We assessed the accuracy of the ABCD2 score for predicting stroke at 7 (primary outcome) and 90 days.

Methods:

This prospective cohort study enrolled adults from eight Canadian emergency departments who had received a diagnosis of transient ischemic attack. Physicians completed data forms with the ABCD2 score before disposition. The outcome criterion, stroke, was established by a treating neurologist or by an Adjudication Committee. We calculated the sensitivity and specificity for predicting stroke 7 and 90 days after visiting the emergency department using the original “high-risk” cutpoint of an ABCD2 score of more than 5, and the American Heart Association recommendation of a score of more than 2.

Results:

We enrolled 2056 patients (mean age 68.0 yr, 1046 (50.9%) women) who had a rate of stroke of 1.8% at 7 days and 3.2% at 90 days. An ABCD2 score of more than 5 had a sensitivity of 31.6% (95% confidence interval [CI] 19.1–47.5) for stroke at 7 days and 29.2% (95% CI 19.6–41.2) for stroke at 90 days. An ABCD2 score of more than 2 resulted in sensitivity of 94.7% (95% CI 82.7–98.5) for stroke at 7 days with a specificity of 12.5% (95% CI 11.2–14.1). The accuracy of the ABCD2 score as calculated by either the enrolling physician (area under the curve 0.56; 95% CI 0.47–0.65) or the coordinating centre (area under the curve 0.65; 95% CI 0.57–0.73) was poor.

Interpretation:

This multicentre prospective study involving patients in emergency departments with transient ischemic attack found the ABCD2 score to be inaccurate, at any cut-point, as a predictor of imminent stroke. Furthermore, the ABCD2 score of more than 2 that is recommended by the American Heart Association is nonspecific.There are approximately 100 visits to the emergency department per 100 000 population for transient ischemic attack each year.¹ Although often considered benign, transient ischemic attack carries a risk of imminent stroke. Studies have shown that the risk of stroke is 0.2%–10% within 7 days of the first transient ischemic attack, and this risk increases to 1.2%–12% at 90 days.^2–9 Stroke continues to be the leading cause of disability among adults and the third-leading cause of death in North America.^10,11 Identifying people with transient ischemic attack who are at high risk of stroke is an opportunity to prevent stroke.^3,4 However, urgent investigation of all transient ischemic attacks would require substantial resources. Three studies have attempted to develop clinical decision rules (i.e., scores) for assessing whether a patient with transient ischemic attack is at high risk of stroke.^9,12,13 Combined, these studies led to the development of the ABCD2 (Age, Blood pressure, Clinical features, Duration of symptoms and Diabetes) score. However, despite its widespread implementation, the ABCD2 score has not yet been prospectively validated.^12,14–18 This essential step in the development of rules for making clinical predictions has recently been requested.^14,19–21The objective of this study was to externally validate the ABCD2 score as a tool for identifying patients seen in the emergency department with transient ischemic attack who are at high risk of stroke within 7 (primary outcome) and 90 days (one of the secondary outcomes).     

Reaction of nitric oxide with heme proteins and model compounds of hemoglobin

Rates for the reaction of nitric oxide with several ferric heme proteins and model compounds have been measured. The NO combination rates are markedly affected by the presence or absence of distal histidine. Elephant myoglobin in which the E7 distal histidine has been replaced by glutamine reacts with NO 500-1000 times faster than do the native hemoglobins or myoglobins. By contrast, there is no difference in the CO combination rate constants of sperm whale and elephant myoglobins. Studies on ferric model compounds for the R and T states of hemoglobin indicate that their NO combination rate constants are similar to those observed for the combination of CO with the corresponding ferro derivatives. The last observation suggests that the presence of an axial water molecule at the ligand binding site of ferric hemoglobin A prevents it from exhibiting significant cooperativity in its reactions with NO.     

N-(4-Hydroxyphenyl)-3,4,5-trimethoxybenzamide derivatives as potential memory enhancers: synthesis,biological evaluation and molecular simulation studies

The present paper describes the synthesis, biological evaluation and molecular simulation studies of a series of N-(4-hydroxyphenyl)-3,4,5-trimethoxybenzamide derivatives with N,N-dialkylaminoethoxy/propoxy moiety as potential memory enhancers with acetylcholinesterase-inhibiting activity having IC₅₀ in low micromolar range (4.0–16.5 μM). All the compounds showed a good degree of agreement between in vivo and in vitro results as most of these derivatives showed dose-dependent increase in percent retention. Compound 10a showed significant % retention of 84.73 ± 4.51 as compared to piracetam (46.88 ± 5.42) at 3 mg kg^?1 and also exhibited a maximal percent inhibition of 97% at 50 μM. Molecular docking, MM-GBSA and molecular simulation studies were performed establishing a correlation between the experimental biology and in silico results. In silico results indicate that all the compounds have better docking scores and predicted binding free energies as compared to cocrystallized ligand with the best potent ligand retaining conserved hydrophobic interactions with residues of catalytic triad (HIS447), catalytic anionic site (CAS) (TRP86, TYR337, PHE338) and peripheral anionic site (PAS) (TYR72, TYR124, TRP286 and TYR341). Root mean square deviation (RMSD = 2.4 Å) and root mean square fluctuations of 10a–AChE complex during simulation proved its stable nature in binding toward acetylcholinesterase. The docked conformation of 10a and other analogs at the binding site have also been simulated with polar and nonpolar interactions interlining the gorge residues from PAS to catalytic triad.     

Insights into phytase-containing transgenic <Emphasis Type="Italic">Lemna minor</Emphasis> (L.) as a novel feed additive

This study assessed the effect of supplementation of novel transgenic phytase on growth performance and bone mineralization in Korean native broiler chickens. The experiment was designed using four dietary groups: those with a diet supplemented with (A) recombinant phytase, (B) transgenic phytase from the plant Lemna minor, (C) or wild-type L. minor as well as (D) a control group that was supplemented with commercially available feed. Three hundred 1-day-old Korean native broiler chicks were used and divided into these four dietary treatment groups having three replicates of 25 birds each (n?=?75). The results showed increases in growth performance and bone mineralization in Groups B and C; compared with Groups A and D. Hematological analyses revealed notable contrasts in erythrocyte sedimentation rate, red blood cell count, and hemoglobin levels among the experimental groups, whereas no impacts of dietary treatment were observed on total eosinophil, lymphocyte, heterophil, monocyte, and basophil levels. The relative expression profiling of candidate genes showed that the genes involved in growth response, meat quality, and P–Ca metabolism were significantly highly expressed in the phytase-supplemented groups. Hence, it is suggested that dietary supplementation with transgenic phytase plant L. minor for enhancing growth performance is a promising new approach in the broiler feed industry. To the best of our knowledge, we report here the most comprehensive analysis using a broiler model that provides a workable platform for further research on the cost-effective production of feed with different compositions that might be beneficial in the livestock feed industry.     

Solid-State Stability Issues of Drugs in Transdermal Patch Formulations

The transdermal patch formulation has many advantages, including noninvasiveness, an ability to bypass the first-pass metabolism, low dosage requirements, and prolonged drug delivery. However, the instability of solid-state drugs is one of the most critical problems observed in transdermal patch products. Therefore, a well-characterized approach for counteracting stability problems in solid-state drugs is crucial for improving the performance of transdermal patch products. This review provides insight into the solid-state stability of drugs associated with transdermal patch products and offers a comprehensive update on the various approaches being used for improving the stability of the active pharmaceutical ingredients currently being used.     

Introgression and confirmation of everbearing trait in strawberry (Fragaria x ananassa Duch.)

The present investigation was targeted towards a highly desirable everbearing trait in strawberry (Fragaria × ananassa Duch.) via marker assisted selection while seeing its worldwide commercial applicability through the extended harvest season. The crosses were made between everbearing and june-bearing cultivars to raise the F₁ individuals. Morphological characters (plant, floral, and fruit) were assessed that showed significant differences among the strawberry cultivars. Molecular characterization was carried out between everbearing and non-everbearing cultivars using RAPD and SSR markers. For phenotyping, a chi-square test was performed and revealed that out of all four cross combinations, the best fitted cross found to be in Mendelian segregation ratio (1:1) was ‘Confectura’ × ‘Torrey’ with χ²-value 1.58. Further, the identified polymorphic markers were assessed across the F₁ individuals of cross ‘Confectura’ × ‘Torrey’ for its genotyping. It could be revealed that the targeted everbearing trait is governed by a dominant gene(s) in the subjected strawberry genotypes. Further, the identified polymorphic markers would be successfully employed in DNA fingerprinting of strawberry under various crop improvement programme.Supplementary informationThe online version of this article (10.1007/s12298-020-00916-w) contains supplementary material, which is available to authorized users.