Vanadocene-functionalized mesoporous silica nanoparticles: platforms for the development of theranostic materials against breast cancer

Nanoscale materials have demonstrated a very high potential in anticancer therapy by properly adjusting their functionalization and physicochemical properties. Herein, we report the synthesis of some novel vanadocene-loaded silica-based nanomaterials incorporating four different S-containing amino acids (penicillamine, methionine, captopril, and cysteine) and different fluorophores (rhodamine B, coumarin 343 or Alexa Fluor™ 647), which have been characterized by diverse solid-state spectroscopic techniques viz; FTIR, diffuse reflectance spectroscopies,13C and51V solid-state NMR spectroscopy, thermogravimetry and TEM. The analysis of the biological activity of the novel vanadocene-based nanostructured silicas showed that the materials containing cysteine and captopril aminoacids demonstrated high cytotoxicity and selectivity against triple negative breast cancer cells, making them very promising antineoplastic drug candidates. According to the biological results it seems that vanadium activity is connected to its incorporation through the amino acid, resulting in synergy that increases the cytotoxic activity against cancer cells of the studied materials presumably by increasing cell internalization. The results presented herein hold significant potential for future developments in mesoporous silica-supported metallodrugs, which exhibit strong cytotoxicity while maintaining low metal loading. They also show potential for theranostic applications highlighted by the analysis of the optical properties of the studied systems after incorporating rhodamine B, coumarin 343 (possible)in vitroanticancer analysis, or Alexa Fluor™ 647 (in vivostudies of cancer models).

Cheminformatics-based discovery of new organoselenium compounds with potential for the treatment of cutaneous and visceral leishmaniasis

Leishmaniasis affects more than 12 million humans globally and a further 1 billion people are at risk in leishmaniasis endemic areas. The lack of a vaccine for leishmaniasis coupled with the limitations of existing anti-leishmanial therapies prompted this study. Cheminformatic techniques are widely used in screening large libraries of compounds, studying protein-ligand interactions, analysing pharmacokinetic properties, and designing new drug molecules with great speed, accuracy, and precision. This study was undertaken to evaluate the anti-leishmanial potential of some organoselenium compounds by quantitative structure-activity relationship (QSAR) modeling, molecular docking, pharmacokinetic analysis, and molecular dynamic (MD) simulation. The built QSAR model was validated (R2train = 0.8646, R2test = 0.8864, Q2 = 0.5773) and the predicted inhibitory activity (pIC50) values of the newly designed compounds were higher than that of the template (Compound 6). The new analogues (6a, 6b, and 6c) showed good binding interactions with the target protein (Pyridoxal kinase, PdxK) while also presenting excellent drug-likeness and pharmacokinetic profiles. The results of density functional theory, MD simulation, and molecular mechanics generalized Born surface area (MM/GBSA) analyses suggest the favourability and stability of protein-ligand interactions of the new analogues with PdxK, comparing favourably well with the reference drug (Pentamidine). Conclusively, the newly designed compounds could be synthesized and tested experimentally as potential anti-leishmanial drug molecules.Communicated by Ramaswamy H. Sarma.

Computational design, molecular properties, ADME, and toxicological analysis of substituted 2,6-diarylidene cyclohexanone analogs as potent pyridoxal kinase inhibitors

Leishmaniasis is one of the tropical diseases which affects over 12 million people mainly in the tropical regions of the world and is caused by the leishmanial parasites transmitted by the female sand fly. The lack of vaccines to prevent leishmaniasis, as well as limitations of existing therapies necessitated this study which was focused on a combined virtual docking screening and 3-D QSAR modeling approach to design some diarylidene cyclohexanone analogs, while also performing pharmacokinetic analysis and Molecular Dynamic (MD) simulation to ascertain their drug-ability. As a result, the built 3-D QSAR model was found to satisfy the requirement of a good model with R2 = 0.9777, SDEC = 0.0593, F-test = 105.028, and Q2 LOO = 0.6592. The template (compound 9, MolDock score =  - 161.064) and all seven newly designed analogs were found to possess higher docking scores than the reference drug (Pentamidine, Moldock score = - 137.827). The results of the pharmacokinetic analysis suggest 9 and the new molecules (9a, b, c, e, and f) as orally bioavailable with good ADME and safe toxicological profiles. These molecules also showed good binding interactions with the receptor (pyridoxal kinase). Additionally, the MD simulation result confirmed the stability of the tested protein-ligand complexes, with an estimated ∆G binding (MM/GBSA) of - 65.2177 kcal/mol and - 58.433 kcal/mol for 9_6K91 and 9a_6K91 respectively. Hence, the new compounds, especially 9a could be considered potential anti-leishmanial inhibitors.

Application of Piszkiewicz model on the electron transfer reaction of dithionite ion and bis-(2-pyridinealdoximato)dioxomolybdate(IV) complex

The need to better understand the binding mode of antioxidants (sulfur oxyanions) kinetically is a concern in medicine. Hence, a spectrophotometric method was used to study the application of the Piszkiewicz model on the electron transfer reaction of dithionite ion (S₂O₄^2-) and bis-(2-pyridinealdoximato)dioxomolybdate(IV) complex at 303 K and an absorption maxima of 560 nm. It follows an acid dependent reductive pathway that is medium sensitive. Charge distribution from the reaction species contributes to the redox efficiency of the system, resulting in a primary salt effect (NaCl) with an enhanced reaction rate. Alteration of the reaction medium with ethanol led to an elevation of reduction time as the charge catalysis was distorted by a drop in the system permittivity. Likewise, sodium dodecyl sulfate in the system decreased the reduction rate of the complex due to the low impact of hydrophobic and ion interaction between the micelle and substrates. First order reaction kinetics was observed in the concentration of the redox partners and a 2:1 (complex: S₂O₄^2-) stoichiometry was obtained with the involvement of hydrogenated sulfite radical which resulted in the formation of sulfur dioxide and a Mo²⁺ deactivated complex. The occurrence of counterion catalysis is pronounced in the reaction system owing to the participation of like-charged substrates in the rate-controlling phase. The standard enthalpy (69.12 [Formula: see text] 0.05 kJ mol^-1) and Gibbs energy (80.10 [Formula: see text] 0.07) kJ mol^-1 suggest that the process is endothermic dependent. The investigation of the anionic surfactant effect on the reaction medium was quantitatively ascertained from the Piszkiewicz model of the complex interaction sequence.

Molecular docking-based virtual screening, molecular dynamic simulation, and 3-D QSAR modeling of some pyrazolopyrimidine analogs as potent anti-filarial agents

Lymphatic filariasis and onchocerciasis are common filarial diseases caused by filarial worms, which co-habit symbiotically with the Wolbachia organism. One good treatment method seeks Wolbachia as a drug target. Here, a computer-aided molecular docking screening and 3-D QSAR modeling were conducted on a series of Fifty-two (52) pyrazolopyrimidine derivatives against four Wolbachia receptors, including a pharmacokinetics study and Molecular Dynamic (MD) investigation, to find a more potent anti-filarial drug. The DFT approach (B3LYP with 6-31G** option) was used for the structural optimization. Five ligand-protein interaction pairs with the highest binding affinities were identified in the order; 23_7ESX (-10.2 kcal/mol) > 14_6EEZ (- 9.0) > 29_3F4R (- 8.0) > 26_6W9O (- 7.7) ≈ doxycycline_7ESX (- 7.7), with good pharmacological interaction profiles. The built 3-D QSAR model satisfied the requirement of a good model with R2 = 0.9425, Q2 LOO = 0.5019, SDEC = 0.1446, and F test = 98.282. The selected molecules (14, 23, 26, and 29) perfectly obeyed Lipinski's RO5 for oral bio-availability, and showed excellent ADMET properties, except 14 with positive AMES toxicity. The result of the MD simulation showed the great stability associated with the binding of 23 onto 7ESX's binding pocket with an estimated binding free energy (MM/GBSA) of - 60.6552 kcal/mol. Therefore, 23 could be recommended as a potential anti-filarial drug molecule, and/or template for the design of more prominent inhibitors.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40203-022-00136-y.

The study of Piszkiewicz’s and Berezin’s models on the redox reaction of allylthiourea and bis-(2-pyridinealdoximato)dioxomolybdate(IV) complex in an aqueous acidic medium

Background

The study of Piszkiewicz’s and Berezin’s models on the redox reaction of allylthiourea and bis-(2-pyridinealdoximato)dioxomolybdate(IV) complex ([MoIVO2(paoH)2]2−) in an aqueous acidic medium is suggested. The Piszkiewicz’s and Berezin’s models are applied, and their parameters are used to explain the redox behaviour of allylthiourea with Mo(IV) complex in the presence of surfactants.

Results

The reaction followed a high cooperativity pattern that reflects a strong interaction between the two redox partners in the presence of cetyltrimethylammonium bromide (CTAB) which is reinforced by a notable binding constant at the Stern layer of the micelle. The effect of cationic counter-ion (Ca2+) on the reaction rate further confirmed the effectiveness of the interaction at the rate-limiting step. The presence of sodium dodecyl sulphate (SDS) in the reaction medium resulted in reaction inhibition which reveals the interplay of electrostatic repulsion at the electrophilic polar head of the surfactant and the redox species. The effect of ionic strength on the reaction rate shows that one of the reacting species is not charged (neutral) which kept the rate of the reaction uniform at different salt concentrations studied. The change in the medium polarity buttressed the effect of ionic strength on the reaction which is explained better by Piszkiewicz’s and Berezin’s models. Free radical was actively engaged in the reductive process of the Mo(IV) complex, and this revealed that the hydrophobic region is a possible location for the interaction of the redox partner in the presence of SDS micelle.

Conclusions

The models depict well the microenvironments of enzymatic reactions involving bimolecular interactions with significant binding constants and cooperativity indexes that show the strength of the interaction between the substrates and surfactant molecules.

Graphical Abstract

Theoretical modeling and design of some pyrazolopyrimidine derivatives as Wolbachia inhibitors, targeting lymphatic filariasis and onchocerciasis

Lymphatic filariasis and onchocerciasis are two common filarial diseases caused by a group of parasitic nematodes called filarial worms, which play host to the bacteria organism Wolbachia. One good treatment approach seeks Wolbachia as drug target. Here, a QSAR study was conducted to investigate the anti-wolbachia activities (pEC₅₀) of 52 pyrazolopyrimidine analogues, while using the built model to predict the pEC₅₀ values of the newly designed analogues. Density Functional Theory was used for the structural optimization, while the model building was based on Genetic Function Algorithm approach. The built QSAR model was validated thus: R² = 0.8104, R² _adj = 0.7629, Q² _cv = 0.6981, R² _test = 0.7501 and cRp² = 0.7476. The predicted pEC₅₀ of all newly designed compounds were higher than that of the template (43). The new compounds were; observed to pass the drug-likeness criteria, uniformly distributed to the brain, and found to be non-mutagenic. Also, the new compounds and the reference drug (doxycycline), were docked onto Ovarian Tumor (OTU) deubiquitinase receptor (PDB ID: 6W9O) using iGEMDOCK tool. This protein is known to help Wolbachia subvert host ubiquitin signaling. The resulting binding scores of the newly designed compounds except A5 were higher than that of doxycycline, while the protein-ligand interactions were majorly characterized by Hydrogen-bonding and hydrophobic interaction types. Therefore, the newly designed molecules could be developed as potential drug candidates for the treatment of lymphatic filariasis and onchocerciasis.

Effect of annealing temperature on the synthesis and photocatalytic properties of Bi0.65K0.2Ba0.15FeO3 perovskite-like nanoparticle synthesized by sol-gel method

Background

BiFeO3 shows promising applications in photocatalytic degradation, purification process, and in clean energy generation. The various fascinating properties of bismuth ferrite nanoparticles can be improved by doping the material at either of the A or B sites to give it extra photocatalytic advantage toward decreasing the energy bandgap and other photophysical properties of the material.

Results

In this research, pure Bi0.65K0.2Ba0.15FeO3 perovskite material was synthesized using the sol-gel method via citric acid route in the presence of sodium dodecyl sulfate (SDS). The powdered nanoparticles were annealed at different annealing temperatures of 600, 700, and 800 °C each for 4 h in a muffle furnace and coded K2BFO 600, K2BFO 700, and K2BFO 800 corresponding to the annealing temperature of each portion. The powder nanoparticles were characterized using powdered X-ray diffraction (PXRD) to determine the crystallite structure. The samples displayed similar peak patterns with increase in intensity as the annealing temperature is increased indicating an increase in crystallinity. The impurity peaks in K2BFO 800, however, show that the sample may contain a secondary phase. Scanning electron microscopy (SEM) was used to determine the morphology, and UV-Vis spectroscopy indicated that all the powders were photoactive within the visible region of the electromagnetic spectrum. ATR-FTIR spectra of the samples were collected to study the formation and phase purity of the B-site in the perovskite structures. The photocatalytic performance of the powder was tested on methylene blue dye under visible light irradiation for the degradation studies. All powders showed photocatalytic ability after 2 h of irradiation with the powder annealed at 800 °C being better. The photocatalytic activities of the powders showed improvement on addition of 2 drops of 1 M H2O2 (80% degradation for K2BFO 800). The bandgap energy of K2BFO 800, 700, and 600 was estimated at approximately 2.00, 2.12, and 2.18 eV, respectively, using Tauc’s equation. The improved activity is as a result of photoabsorption of visible light by the doped powders causing generation of electrons and holes. The kinetic studies were carried out and the mechanisms of the photocatalytic reaction proposed.

Conclusion

The effect of annealing temperature on synthesis of the material shows enhanced photoactivity in the presence of hydrogen peroxide leading to improved performance for the degradation of MB, and the catalyst can be said to be a good candidate for the treatment of waste materials.

Photocatalytic activity and doping effects of BiFeO3 nanoparticles in model organic dyes

The studies of advanced materials in environmental remediation and degradation of pollutants is rapidly advancing because of their wide varieties of applications. BiFeO₃ (BFO), a perovskite nanomaterial with a rhombohedral R3c space group, is currently receiving tremendous attention in photodegradation of dyes. The photocatalytic activity of BFO nanoparticle is a promising field of research in photocatalysis. BFO nanomaterial is a photocatalyst enhanced by doping because of its reduce bandgap energy (2.0–2.77 eV), multiferroic property, strong photoabsorption and crystal structure. The material has proven to be very useful for the degradation of dyes under visible light irradiation among other photocatalysts. Its exceptional nontoxicity, suitability, low cost and long term excellent stability makes it an efficient photocatalyst for the degradation of effluents from textile and pharmaceutical industries which ended-up in the environment and now a major concern of the modern world. This mini-review attempts to provide some detailed synthetic routes of BFO and BFO related nanomaterials and the notable achievements so far on the effect of doping the material. It also discusses the effect of crystallite size of the material and other photophysical properties and how they influence the photocatalytic process of model organic dye pollutants, to date.

The mantoux test: should we change the site?

Recent studies have shown that sunlight-induced immunosuppression negatively alters the skin response to mantoux test. This study aimed to compare the response of the skin to mantoux test over the volar forearm surface, the traditional site, which is exposed to sunlight and the inner thigh, an area which is not. In all, 45 children had the mantoux test administered using 0.1 mL of 5TU purified protein derivative. Reactive induration to the mantoux test was recorded in five of these children. The average induration of the volar surface was 8.2 mm, while that at the inner thigh was 11.6 mm. The results have highlighted the potential of an enhanced mantoux test result, if parts of the body that are not exposed to high doses of ultraviolet light are used as the site for mantoux test.

Acardius Acephalus in an Undiagnosed Twin Gestation; Case Report and review of Literature from Federal Medical Centre Gusau, Zamfara State, Northwestern Nigeria

BACKGROUND

Acardiusacephalusfoetal anomaly is a rare abnormality occurring in multifoetal gestation particularly monozygous twin gestation. It is commonly characterized by varying gross structural malformations incompatible with extra uterine life. Reports on acardiusacephalusfoetal anomaly remain sparse. We report a case of acardiusacephalusin an undiagnosed twin with striking gross malformation delivered to a 28 year old un-booked multipara. Objective To report an acardiusacephalic anomaly in the second of an undiagnosed twin pregnancy delivered to a multipara and review relevant literature.

METHOD

A Case was fully documentedat the Federal medical centre Gusau, Nigeria and local and international literature search conducted and reviewed.

CONCLUSION

Acardiusacephalus may have additional malformations in the other organs. The current case, the first in our centre, shows yet other striking gross and severe malformations characterizing acardiusacephalus.

Nasal Bubble CPAP: One Year Experience in a Neonatal Unit of a Tertiary Health Facility in Northwestern Nigeria

AIMS AND OBJECTIVES

Nasal bubble continuous positive airway pressure (NBCPAP) respiratory support, though decades old, is beginning to gain popularity in developing countries including Nigeria. We reviewed neonates who benefitted from NBCPAP, to describe the demographics and outcome of NBCPAP respiratory support in newborns admitted to the neonatal unit of Ahmadu Bello University Teaching Hospital (ABUTH), Zaria, over a one year period.

MATERIALS AND METHODS

The study is a descriptive observational review of all neonates who required NBCPAP respiratory support in the neonatal unit of ABUTH Zaria. Data was extracted from a specifically designed proforma used to obtain information on each neonate throughout the period of admission.

RESULTS

Twenty babies received NBCPAP respiratory support during the period of study. Seventeen (85%) of the neonates were successfully weaned off CPAP while three (15%) failed CPAP. Three neonates developed complications with two having CPAP belly syndrome and the third had facial swelling which resolved spontaneously after 6 hours. Overall, seven (41%) of the neonates who were successfully weaned off CPAP were discharged home.

CONCLUSION

MajorityofnewbornswhorequirerespiratorysupportwillbenefitfromNBCPAP therefore, this method of respiratory support should be popularized and neonatal units in the country should be supported to efficiently offer the service.

Outcome of Extremely Low Birth Weight Babies in Zaria; A Ten-Year Review

BACKGROUND

Survival among extremely low birth weight (ELBW) babies (birth weight below 1000grams) in resource limited settings is still very low. The study aimed to determine the correlation between materno-foetal factors and outcome in this category of neonates.

STUDY DESIGN

A retrospective study in which patients' records admitted into the Neonatal Unit of Ahmadu Bello University Teaching Hospital between January 2005 and December 2014 were retrieved. Information on neonates weighing < 1000 g were extracted and analyzed. Survival at discharge was the primary outcome.

RESULTS

The overall survival rate of extremely low birth weight babies was 18%. Mortality in ELBW neonates weighing less than 750g was 100%. Factors that were significantly predictive of survival were birth weight, parity and duration of hospital stay with p-values of 0.014, 0.039 and 0.025 respectively

CONCLUSION

The survival rate of ELBW babies remains low in our resource constrained setting. Focus should be on preventing preterm deliveries and as well equipping newborn care providers and newborn units with the necessary skills and materials respectively to enable implementation of evidence based interventions to improve newborn survival.