Cryopreservation of bovine semen using extract of Cinnamomum zeylanicum

BACKGROUND

Antioxidants minimise oxidative stress and enhance sperm quality in the process of cryopreservation.

OBJECTIVE

To assess the impact of Cinnamomum zeylanicum extract as an additive during the post-dilution and post-thaw stages of Murrah buffalo semen cryopreservation.

MATERIALS AND METHODS

The semen sample was diluted using Tris-Egg-Yolk-Citric-Acid-Fructose-Glycerol extender and subsequently divided into three groups: Group 1, TEYCAFG without any additives or controls (C); Group 2, TEYCAFG fortified with a 50 ug/mL aqueous extract of cinnamon (T1); and Group 3, TEYCAFG fortified with a 50 ug/mL ethanolic extract of cinnamon (T2). The evaluation included an assessment of progressive motility, live spermatozoa, sperm abnormalities, HOST, CMPT, and enzyme leakage (GOT and GPT) at both the post-dilution and post-thaw stages.

RESULTS

The groups that received cinnamon supplementation demonstrated statistically significant improvements (p<0.05) in various parameters, including an increase in the progressive motility, live spermatozoa, and HOS-positive spermatozoa, as well as greater distance traveled by vanguard spermatozoa compared to the control group. Furthermore, the cinnamon-added groups exhibited a significant decrease (p<0.05) in the percentage of sperm abnormalities and lower enzyme leakage (GOT and GPT) in post-thawed semen.

CONCLUSION

Aqueous extract of C. zeylanicum at a concentration of 50 µg/mL provides superior protection of sperm structures and functions as compared to both the ethanolic extract of C. zeylanicum at the same concentration and the control group. Doi.org/10.54680/fr24310110712.

Leveraging Modeling and Simulation to Enhance the Efficiency of Bioequivalence Approaches for Generic Drugs: Highlights from the 2023 Generic Drug Science and Research Initiatives Public Workshop

The 2023 Generic Drug Science and Research Initiative Public Workshop organized by the U.S. Food and Drug Administration (FDA) discussed the research needs to improve and enhance bioequivalence (BE) approaches for generic drug development. FDA takes such research needs and panel discussions into account to develop its Generic Drug User Fee Amendments III (GDUFA III) Science and Research Initiatives specific to generics. During the five workshop sessions, presentations and panel discussions focused on identifying and addressing scientific gaps and research needs related to nitrosamine impurity issues, BE assessment for oral products, innovative BE approaches for long-acting injectable products, alternative BE approaches for orally inhaled products, and advanced BE methods for topical products. Specifically, this report highlights the discussions on how to improve BE assessment for developing generic drug products based on research priorities for leveraging quantitative methods and modeling, as well as artificial intelligence/machine learning (AI/ML).

Assessing Trans-Inhibition of OATP1B1 and OATP1B3 by Calcineurin and/or PPIase Inhibitors and Global Identification of OATP1B1/3-Associated Proteins

Organic anion transporting polypeptide (OATP) 1B1 and OATP1B3 are key determinants of drug-drug interactions (DDIs). Various drugs including the calcineurin inhibitor (CNI) cyclosporine A (CsA) exert preincubation-induced trans-inhibitory effects upon OATP1B1 and/or OATP1B3 (abbreviated as OATP1B1/3) by unknown mechanism(s). OATP1B1/3 are phosphoproteins; calcineurin, which dephosphorylates and regulates numerous phosphoproteins, has not previously been investigated in the context of preincubation-induced trans-inhibition of OATP1B1/3. Herein, we compare the trans-inhibitory effects exerted on OATP1B1 and OATP1B3 by CsA, the non-analogous CNI tacrolimus, and the non-CNI CsA analogue SCY-635 in transporter-overexpressing human embryonic kidney (HEK) 293 stable cell lines. Preincubation (10-60 min) with tacrolimus (1-10 µM) rapidly and significantly reduces OATP1B1- and OATP1B3-mediated transport up to 0.18 ± 0.03- and 0.20 ± 0.02-fold compared to the control, respectively. Both CsA and SCY-635 can trans-inhibit OATP1B1, with the inhibitory effects progressively increasing over a 60 min preincubation time. At each equivalent preincubation time, CsA has greater trans-inhibitory effects toward OATP1B1 than SCY-635. Preincubation with SCY-635 for 60 min yielded IC50 of 2.2 ± 1.4 µM against OATP1B1, which is ~18 fold greater than that of CsA (0.12 ± 0.04 µM). Furthermore, a proteomics-based screening for protein interactors was used to examine possible proteins and processes contributing to OATP1B1/3 regulation and preincubation-induced inhibition by CNIs and other drugs. A total of 861 and 357 proteins were identified as specifically associated with OATP1B1 and OATP1B3, respectively, including various protein kinases, ubiquitin-related enzymes, the tacrolimus (FK506)-binding proteins FKBP5 and FKBP8, and several known regulatory targets of calcineurin. The current study reports several novel findings that expand our understanding of impaired OATP1B1/3 function; these include preincubation-induced trans-inhibition of OATP1B1/3 by the CNI tacrolimus, greater preincubation-induced inhibition by CsA compared to its non-CNI analogue SCY-635, and association of OATP1B1/3 with various proteins relevant to established and candidate OATP1B1/3 regulatory processes.

Mechanistic modeling of ophthalmic, nasal, injectable, and implant generic drug products: A workshop summary report

For approval, a proposed generic drug product must demonstrate it is bioequivalent (BE) to the reference listed drug product. For locally acting drug products, conventional BE approaches may not be feasible because measurements in local tissues at the sites of action are often impractical, unethical, or cost-prohibitive. Mechanistic modeling approaches, such as physiologically-based pharmacokinetic (PBPK) modeling, may integrate information from drug product properties and human physiology to predict drug concentrations in these local tissues. This may allow clinical relevance determination of critical drug product attributes for BE assessment during the development of generic drug products. In this regard, the Office of Generic Drugs of the US Food and Drug Administration has recently established scientific research programs to accelerate the development and assessment of generic products by utilizing model-integrated alternative BE approaches. This report summarizes the presentations and panel discussion from a public workshop that provided research updates and information on the current state of the use of PBPK modeling approaches to support generic product development for ophthalmic, injectable, nasal, and implant drug products.

Mechanistic Modeling of In Vitro Skin Permeation and Extrapolation to In Vivo for Topically Applied Metronidazole Drug Products Using a Physiologically Based Pharmacokinetic Model

Physiologically based pharmacokinetic (PBPK) modeling has increasingly been employed in dermal drug development and regulatory assessment, providing a framework to integrate relevant information including drug and drug product attributes, skin physiology parameters, and population variability. The current study aimed to develop a stepwise modeling workflow with knowledge gained from modeling in vitro skin permeation testing (IVPT) to describe in vivo exposure of metronidazole locally in the stratum corneum following topical application of complex semisolid drug products. The initial PBPK model of metronidazole in vitro skin permeation was developed using infinite and finite dose aqueous metronidazole solution. Parameters such as stratum corneum lipid-water partition coefficient (K_sclip/water) and stratum corneum lipid diffusion coefficient (D_sclip) of metronidazole were optimized using IVPT data from simple aqueous solutions (infinite) and MetroGel (10 mg/cm² dose application), respectively. The optimized model, when parameterized with physical and structural characteristics of the drug products, was able to accurately predict the mean cumulative amount permeated (cm²/h) and flux (μg/cm²/h) profiles of metronidazole following application of different doses of MetroGel and MetroCream. Thus, the model was able to capture the impact of differences in drug product microstructure and metamorphosis of the dosage form on in vitro metronidazole permeation. The PBPK model informed by IVPT study data was able to predict the metronidazole amount in the stratum corneum as reported in clinical studies. In summary, the proposed model provides an enhanced understanding of the potential impact of drug product attributes in influencing in vitro skin permeation of metronidazole. Key kinetic parameters derived from modeling the metronidazole IVPT data improved the predictions of the developed PBPK model of in vivo local metronidazole concentrations in the stratum corneum. Overall, this work improves our confidence in the proposed workflow that accounts for drug product attributes and utilizes IVPT data toward improving predictions from advanced modeling and simulation tools.

Multi-phase multi-layer mechanistic dermal absorption (MPML MechDermA) model to predict local and systemic exposure of drug products applied on skin

Physiologically-based pharmacokinetic models combine knowledge about physiology, drug product properties, such as physicochemical parameters, absorption, distribution, metabolism, excretion characteristics, formulation attributes, and trial design or dosing regimen to mechanistically simulate drug pharmacokinetics (PK). The current work describes the development of a multiphase, multilayer mechanistic dermal absorption (MPML MechDermA) model within the Simcyp Simulator capable of simulating uptake and permeation of drugs through human skin following application of drug products to the skin. The model was designed to account for formulation characteristics as well as body site- and sex- population variability to predict local and systemic bioavailability. The present report outlines the structure and assumptions of the MPML MechDermA model and includes results from simulations comparing absorption at multiple body sites for two compounds, caffeine and benzoic acid, formulated as solutions. Finally, a model of the Feldene (piroxicam) topical gel, 0.5% was developed and assessed for its ability to predict both plasma and local skin concentrations when compared to in vivo PK data.

Amphotericin B release rate is the link between drug status in the liposomal bilayer and toxicity

Amphotericin B (AmB) is an amphiphilic drug commonly formulated in liposomes and administered intravenously to treat systemic fungal infections. Recent studies on the liposomal drug product have shed light on the AmB aggregation status in the bilayer, which heat treatment (curing) modifies. Although toxicity was found related to aggregation status - loose aggregates significantly more toxic than tight aggregates - the precise mechanism linking aggregation and toxicity was not well understood. This study directly measured drug release rate from various AmB liposomal preparations made with modified curing protocols to evaluate correlations among drug aggregation state, drug release, and in vitro toxicity. UV–Vis spectroscopy of these products detected unique curing-induced changes in the UV spectral features: a ∼25 nm blue-shift of the main absorption peak (λ_max) in aqueous buffer and a decrease in the OD₃₄₆/OD₃₂₂ ratio upon thermal curing, reflecting tighter aggregation. In vitro release testing (IVRT) data showed, by applying and fitting first-order release kinetic models for one or two pools, that curing impacts two significant changes: a 3–5-fold drop in the overall drug release rate and a ten-fold decrease in the ratio between the loosely aggregated and the tightly aggregated, more thermodynamically stable drug pool. The kinetic data thus corroborated the trend independently deduced from the UV–Vis spectral data. The in vitro toxicity assay indicated a decreased toxicity with curing, as shown by the significantly increased concentration, causing half-maximal potassium release (TC₅₀). The data suggest that the release of AmB requires dissociation of the tight complexes within the bilayer and that the reduced toxicity relates to this slower rate of dissociation. This study demonstrates the relationship between AmB aggregation status within the lipid bilayer and drug release (directly measured rate constants), providing a mechanistic link between aggregation status and in vitro toxicity in the liposomal formulations.

Preparation, spectroscopic, thermal and molecular docking studies of covid-19 protease on the manganese(II), iron(III), chromium(III) and cobalt(II) creatinine complexes

ABSTRACT. Creatinine biomolecule has three different coordination modes through the (exocyclic O(5) and ring N(1)), (imine N(2) and ring N(1)) or as monodentate ligand via exocyclic O(1)). The FTIR and electronic spectra of the synthesized manganese(II), iron(III), chromium(III), and cobalt(II) complexes consistent with the coordinated behavioral derived from the structural analyses. Thermogravimetric data agree with the stoichiometry and proposed formulas [Mn(C4H7N3O)2(Cl)2]4H2O, [Fe(C4H7N3O)2(Cl)2]Cl.6H2O, [Cr(C4H7N3O)2(Cl)2]Cl.6H2O, and [Co(C4H7N3O)2(Cl)2]6H2O. Four new transition metal complexes derived from the reaction of creatinine chelate and metal salt (MnCl2.4H2O, FeCl3.6H2O, CrCl3.6H2O, and CoCl2.6H2O), were prepared with 1:2 (metal: ligand) stoichiometry, isolated and well characterized by a different spectral and analytical techniques including FTIR, UV/Vis, magnetic susceptibility, molar conductance, elemental analysis, and TGA/DrTGA/DTA. The solid complexes were formed with the binding of the creatinine ligand through exocyclic O(5) and ring N(1) and presented as an octahedral geometry. In addition molecular docking calculations have been performed between complexes of manganese(II), iron(III), chromium(III) and cobalt(II) with creatinine biomolecule ligand with the Covid-19 protease (6LU7) to determine the best binding site and its inhibitory effect.                     KEY WORDS: Creatinine, Coordination, Transition metals, TGA/DTA, Octahedral geometry   Bull. Chem. Soc. Ethiop. 2021, 35(2), 399-412. DOI: https://dx.doi.org/10.4314/bcse.v35i2.13

Physiologically-Based Pharmacokinetic Modeling to Support Determination of Bioequivalence for Dermatological Drug Products: Scientific and Regulatory Considerations

Physiologically-based pharmacokinetic (PBPK) modeling and simulation provides mechanism-based predictions of the pharmacokinetics of an active ingredient following its administration in humans. Dermal PBPK models describe the skin permeation and disposition of the active ingredient following the application of a dermatological product on the skin of virtual healthy and diseased human subjects. These models take into account information on product quality attributes, physicochemical properties of the active ingredient and skin (patho)physiology, and their interplay with each other. Regulatory and product development decision makers can leverage these quantitative tools to identify factors impacting local and systemic exposure. In the realm of generic drug products, the number of US Food and Drug Administratioin (FDA) interactions that use dermal PBPK modeling to support alternative bioequivalence (BE) approaches is increasing. In this report, we share scientific considerations on the development, verification and validation (V&V), and application of PBPK models within the context of a virtual BE assessment for dermatological drug products. We discuss the challenges associated with model V&V for these drug products stemming from the fact that target-site active ingredient concentrations are typically not measurable. Additionally, there are no established relationships between local and systemic PK profiles, when the latter are quantifiable. To that end, we detail a multilevel model V&V approach involving validation for the model of the drug product of interest coupled with the overall assessment of the modeling platform in use while leveraging in vitro and in vivo data related to local and systemic bioavailability.

Assessing OATP1B1- and OATP1B3-Mediated Drug-Drug Interaction Potential of Vemurafenib Using R-Value and Physiologically-Based Pharmacokinetic Models

Organic anion transporting polypeptides (OATP) 1B1 and OATP1B3 are important determinants of transporter-mediated drug-drug interactions (DDIs). Current studies assessed the OATP1B1 and OATP1B3-mediated DDI potential of vemurafenib, a kinase inhibitor drug with high protein binding and low aqueous solubility, using R-value and physiologically-based pharmacokinetic (PBPK) models. The total half-maximal inhibitory concentration (IC_50,total) values of vemurafenib against OATP1B1 and OATP1B3 were determined in 100% human plasma in transporter-overexpressing human embryonic kidney 293 stable cell lines. The unbound fraction of vemurafenib in human plasma before (f_u,plasma) and after addition into the uptake assay plate (f_u,plasma,inc) were determined by rapid equilibrium dialysis. There was no statistically significant difference between f_u,plasma and f_u,plasma,inc. Vemurafenib IC_50,total values against OATP1B1 and OATP1B3 are 175 ± 82 and 231 ± 26 μM, respectively. The R-values [R = 1 + f_u,plasma × I_in,max/(f_u,plasma,inc × IC_50,total)] were then simplified as R = 1+I_in,max/IC_50,total, and were 1.76 and 1.57 for OATP1B1 and OATP1B3, respectively. The simulated pravastatin AUC ratio was 1.28 when a single dose of pravastatin (40 mg) was co-administered with vemurafenib (960 mg, twice daily) at steady-state, compared to pravastatin alone. Both R-value and PBPK models predict that vemurafenib has the potential to cause OATP1B1- and OATP1B3-mediated DDIs.

Successful Multi-vessel Percutaneous Coronary Intervention for Recent Myocardial Infarction in a Patient with Dextrocardia and Situs Inversus

Dextrocardia with situs inversus is a state which is characterized by abnormal positioning of the heart and other internal organs. It is a rare congenital anomaly and the exact cause is not known. More than 60 recognized genes are significant for the proper positioning and patterning of the organs in the body. However, a specific genetic cause of dextrocardia with situs inversus has not been identified and inheritance prototypes have not been established in the majority cases. There are partial available case reports of successful percutaneous coronary intervention (PCI) in these patients who have atherosclerotic coronary artery disease, especially when presenting with myocardial infarction. PCI is technically difficult because of dextrocardia. We hereby describe a 51-year-old male, who had a recent inferior wall myocardial infarction and underwent successful coronary angiography and PCI at a tertiary level hospital in Dhaka, Bangladesh.

Performance evaluation of novel wet vibrational precipitator

This study reports the development, construction, and initial testing of a novel vibrational precipitator (VP), patented at Ohio University in 2016, that uses vibrating metal cables with water running over them to capture particulate matter in an exhaust stream. Unlike traditional electrostatic precipitators relying on electric energy to capture particles, this new system uses the concept of vortex shedding to produce vibrations in vertical cables running perpendicular to an exhaust stream. Collisions between particles in the exhaust stream and these vibrating cables cause the particles to land onto a thin film of flowing water around the cables, which carries the particles downward for collection and removal. Initial tests with air containing particulates of 3 micron average particle size show capture efficiencies up to 54% using U.S. Environmental Protection Agency (EPA) Method 5 to measure the particulate concentrations at the upstream and downstream of a VP comprising 8 cells. These results show that this system, without consuming any electric energy, has a significant potential to be a simple and cost-effective way to treat particle-laden exhaust gases. Implications: In this work, for the first time, a novel precipitator is investigated that captures particles without using any particle charging and (hence) any electricity. The capture mechanism is governed by vibrations of collection electrodes, which are vertical steel cables wetted through continuous flow of water. Without any discharge electrodes, electrode suspension mechanism, and ability of the system to be installed in existing ducts, the novel precipitator becomes a simple chamber housing containing multiple collection electrode cells. The preliminary results show that this new technology can achieve net particulate matter capture efficiency of 54%. This paves a pathway forward for reducing capital and operating cost of air pollution control systems.

Characterization of Plasma Membrane Localization and Phosphorylation Status of Organic Anion Transporting Polypeptide (OATP) 1B1 c.521 T>C Nonsynonymous Single-Nucleotide Polymorphism

PURPOSE

Membrane transport protein organic anion transporting polypeptide (OATP) 1B1 mediates hepatic uptake of many drugs (e.g. statins). The OATP1B1 c.521 T > C (p. V174A) polymorphism has reduced transport activity. Conflicting in vitro results exist regarding whether V174A-OATP1B1 has reduced plasma membrane localization; no such data has been reported in physiologically relevant human liver tissue. Other potential changes, such as phosphorylation, of the V174A-OATP1B1 protein have not been explored. Current studies characterized the plasma membrane localization of V174A-OATP1B1 in genotyped human liver tissue and cell culture and compared the phosphorylation status of V174A- and wild-type (WT)-OATP1B1.

METHODS

Localization of V174A- and WT-OATP1B1 were determined in OATP1B1 c.521 T > C genotyped human liver tissue (n = 79) by immunohistochemistry and in transporter-overexpressing human embryonic kidney (HEK) 293 and HeLa cells by surface biotinylation and confocal microscopy. Phosphorylation and transport of OATP1B1 was determined using ³²P-orthophosphate labeling and [³H]estradiol-17β-glucuronide accumulation, respectively.

RESULTS

All three methods demonstrated predominant plasma membrane localization of both V174A- and WT-OATP1B1 in human liver tissue and in cell culture. Compared to WT-OATP1B1, the V174A-OATP1B1 has significantly increased phosphorylation and reduced transport.

CONCLUSIONS

We report novel findings of increased phosphorylation, but not impaired membrane localization, in association with the reduced transport function of the V174A-OATP1B1.

Preincubation With Everolimus and Sirolimus Reduces Organic Anion-Transporting Polypeptide (OATP)1B1- and 1B3-Mediated Transport Independently of mTOR Kinase Inhibition: Implication in Assessing OATP1B1- and OATP1B3-Mediated Drug-Drug Interactions

Organic anion transporting polypeptides (OATP)1B1 and OATP1B3 mediate hepatic uptake of many drugs including lipid-lowering statins. Current studies determined the OATP1B1/1B3-mediated drug-drug interaction (DDI) potential of mammalian target of rapamycin (mTOR) inhibitors, everolimus and sirolimus, using R-value and physiologically based pharmacokinetic models. Preincubation with everolimus and sirolimus significantly decreased OATP1B1/1B3-mediated transport even after washing and decreased inhibition constant values up to 8.3- and 2.9-fold for OATP1B1 and both 2.7-fold for OATP1B3, respectively. R-values of everolimus, but not sirolimus, were greater than the FDA-recommended cutoff value of 1.1. Physiologically based pharmacokinetic models predict that everolimus and sirolimus have low OATP1B1/1B3-mediated DDI potential against pravastatin. OATP1B1/1B3-mediated transport was not affected by preincubation with INK-128 (10 μM, 1 h), which does however abolish mTOR kinase activity. The preincubation effects of everolimus and sirolimus on OATP1B1/1B3-mediated transport were similar in cells before preincubation with vehicle control or INK-128, suggesting that inhibition of mTOR activity is not a prerequisite for the preincubation effects observed for everolimus and sirolimus. Nine potential phosphorylation sites of OATP1B1 were identified by phosphoproteomics; none of these are the predicted mTOR phosphorylation sites. We report the everolimus/sirolimus-preincubation-induced inhibitory effects on OATP1B1/1B3 and relatively low OATP1B1/1B3-mediated DDI potential of everolimus and sirolimus.

Characterization of Liver- and Cancer-type-Organic Anion Transporting Polypeptide (OATP) 1B3 Messenger RNA Expression in Normal and Cancerous Human Tissues

BACKGROUND

Membrane transport protein organic anion transporting polypeptide (OATP) 1B3 mediates the cellular uptake of many clinically important drugs including anti-cancer drugs (e.g., paclitaxel). In addition to the well-recognized hepatic expression and function of OATP1B3 [herein named liver-type (Lt) OATP1B3], OATP1B3 also expresses in cancers and has been postulated to play a role in cancer therapy, presumably by facilitating the influx of anti-cancer drugs. Recently, a cancer type (Ct)-OATP1B3 mRNA variant was identified in colon and lung cancer tissues, which encodes truncated Ct-OATP1B3 with negligible transport activity. Other than in colon and lung cancers, reports on mRNA expression of OATP1B3 in other cancers cannot distinguish between the Ltand Ct-OATP1B3.

OBJECTIVE

The current studies were designed to characterize the expression of Lt- and Ct-OATP1B3 mRNA in ovarian, prostate, bladder, breast, and lung tissues.

METHODS

Lt- and Ct-OATP1B3 isoform-specific PCR primers were utilized to determine the mRNA levels of Lt- and Ct-OATP1B3, respectively. An expression vector expressing green fluorescent protein (GFP)-tagged Lt-OATP1B3 was transiently transfected into the ovarian cancer cell line SKOV3. Confocal live-cell microscopy was utilized to determine the localization of GFP-Lt-OATP1B3 in SKOV3 cells.

RESULTS

For the first time, Lt-OATP1B3 mRNA was detected in ovarian, prostate, bladder and breast cancers. The localization of GFP-Lt-OATP1B3 on the plasma membrane of SKOV3 cells after transient transfection was readily detected by confocal microscopy.

CONCLUSION

Our findings are supportive of the potential role of Lt-OATP1B3 in cancer cells.

Integration of novel hybrid composite discharge electrode with semi-pilot novel cross-flow electrostatic precipitator

Wet electrostatic precipitators (WESPs) are modern-era pollution control systems specifically designed to capture ultrafine particles as well as acid mist, highly resistive and sticky particles; however, this requires the use of expensive corrosion-resistant metal alloys. The work presented here is part of a continuing study at Ohio University aimed at reducing the cost of WESPs by using a novel combination of a polymer collector surfaces with a hybrid composite discharge electrode. In this study, a hybrid composite discharge electrode was tested, for the first time, inside a semi-pilot-scale experimental setup, with collection surfaces consists of a vertical array of strands. Particle laden gases were passed through this array of polymer ropes, which were kept wet by a small flow of water. The discharge electrodes were composite laminates of carbon fibers in a polymer matrix enclosing a metal mesh. The preliminary results showed that this new integrated system of composite discharge electrode and polymer collector surfaces can match or exceed the performance of a conventional metal alloy electrostatic precipitator (ESP) with metal discharge electrodes. There are additional advantages due to the system being compact, lightweight, and highly corrosion resistant. Implications: This study focused on integrating and assessing performance of a novel hybrid composite electrode (HCE) inside semi-pilot novel cross-flow electrostatic precipitator at conditions typically observed in coal-fired power plant exhausts. The results were collected for particulate collection efficiencies and were compared with a rigid metal electrode. The HCE outperformed metal electrode by showing higher particulate collection efficiency. This result showcases substantial potential for these two new technologies (HCE and cross-flow system) as a substitute for conventional metal based wet ESPs.

Regulation of Organic Anion Transporting Polypeptides (OATP) 1B1- and OATP1B3-Mediated Transport: An Updated Review in the Context of OATP-Mediated Drug-Drug Interactions

Organic anion transporting polypeptides (OATP) 1B1 and OATP1B3 are important hepatic transporters that mediate the uptake of many clinically important drugs, including statins from the blood into the liver. Reduced transport function of OATP1B1 and OATP1B3 can lead to clinically relevant drug-drug interactions (DDIs). Considering the importance of OATP1B1 and OATP1B3 in hepatic drug disposition, substantial efforts have been given on evaluating OATP1B1/1B3-mediated DDIs in order to avoid unwanted adverse effects of drugs that are OATP substrates due to their altered pharmacokinetics. Growing evidences suggest that the transport function of OATP1B1 and OATP1B3 can be regulated at various levels such as genetic variation, transcriptional and post-translational regulation. The present review summarizes the up to date information on the regulation of OATP1B1 and OATP1B3 transport function at different levels with a focus on potential impact on OATP-mediated DDIs.

Study on Hemoglobin Concentration in Patient with Chronic Kidney Disease

In the present study hemoglobin concentration were estimated in chronic kidney diseased patient to observe the frequency of low hemoglobin level in chronic kidney diseased (CKD) patient and to assess the incidence of anaemia. This cross sectional study was carried out in the department of Physiology of Mymensingh Medical College, Mymensingh, Bangladesh from July 2014 to June 2015. For this purpose, total 200 subjects with age ranged from 25 to 60 years were selected and divided into100 healthy persons as control group and 100 CKD patients as study group. Both control and study group were further divided into 50 male and 50 female. Hemoglobin concentration was evaluated by the Cyanmethemoglobin (CMG) method. Statistical analysis of data was done by unpaired student's 't' test. The results showed that hemoglobin levels decreased significantly in chronic kidney diseased patients than the normal healthy persons. The decreasing frequency of hemoglobin level in CKD may predispose the patients to anemia and increasing the other complications.

Interaction between Hypertension and Asthma in Adult

Asthma has been defined as a chronic inflammatory disorder of the airways that is associated with recruitment of inflammatory cells and the clinical development of wheezing, shortness of breath, chest tightness, and cough. The prevalence of asthma increased steadily over the latter part of the last century, first in the developed and then in the developing world. Current estimates suggest that asthma affects 300 million people worldwide, with a predicted additional 100 million people affected by 2025. This cross sectional study was conducted from January 1999 to August 1999 on 5642 Bangladeshi people and another same study carried out from November 2009 to April 2010 on 8088 subjects. In 1999 the prevalence of asthma was 6.9% whereas in 2010 it is 6.96%. Both asthma and hypertension are spastic disorders of smooth muscle, there is the similarities between these two diseases may predispose the individuals with one disease to the other. This descriptive type of cross-sectional study was done to find the Interaction between hypertension and asthma in adult and carried out in the Department of Physiology, Mymensingh Medical College, Mymensingh, Bangladesh from July 2014 to January 2016. Fifty (50) male and fifty (50) female adult asthmatic patients aged 18-60 years were included in the study group. They are enrolled from the Department of Medicine, Mymensingh Medical College, Mymensingh and also from locality. For comparison age matched 50 male and 50 female apparently healthy persons were also studied as control. Blood pressure was estimated by auscultatory method by sphygmomanometer. For statistical analysis unpaired student's 't' test was used. Mean blood pressure were significantly increased in study group in comparison to control group and the result was statistically significant (p<0.001). The study findings showed a high prevalence of hypertension among asthmatic patients than non asthmatic healthy persons. From this study, it may be concluded that hypertension and asthma are closely connected.

Autonomic Reflex Screen Test Abnormalities in Cold-Induced Sweating Syndrome Type 1

Cold-induced sweating syndrome (CISS) is a rare autosomal recessive disease due to mutation in the Cytokine receptor-like factor 1 (CRLF1). The characteristic symptom of CISS is the tendency to sweat profusely especially in the upper body and hands when the patient is exposed to cold temperature. We sought to first report the findings of autonomic reflex screen in a case of CISS type 1 with Cytokine receptor-like factor 1 mutation. Valsalva morphology, Valsalva ratio, and heart rate response to deep breathing were normal for the patient's age. Quantitative sudomotor axon reflex test showed nonlength dependent decrease in the sweat volume. Tilt table revealed evidence of reflex (vasovagal) "syncope," however, the patient was asymptomatic without loss of consciousness.

Treatment with proteasome inhibitor bortezomib decreases organic anion transporting polypeptide (OATP) 1B3-mediated transport in a substrate-dependent manner

OATP1B1 and OATP1B3 mediate hepatic uptake of many drugs (e.g., statins) and can mediate transporter-mediated drug-drug-interactions (DDIs). Bortezomib is the first-in-class proteasome inhibitor drug approved by the U. S. Food and Drug Administration for the treatment of multiple myeloma. The potential of bortezomib to cause OATP-mediated DDIs has not been assessed. The current study investigated the involvement of the ubiquitin-proteasome system (UPS) in OATP1B1 and OATP1B3 degradation and determined the effects of proteasome inhibitors on OATP1B1- and OATP1B3-mediated transport. Co-immunoprecipitation of FLAG-OATP1B1/1B3 and HA-ubiquitin was observed in human embryonic kidney (HEK) 293 cells co-transfected with FLAG-tagged OATP1B1/OATP1B3 and hemagglutinin (HA)-tagged ubiquitin, suggesting that OATP1B1 and OATP1B3 can be ubiquitin-modified. Although blocking proteasome activity by bortezomib treatment (50 nM, 7 h) increased the endogenous ubiquitin-conjugated FLAG-OATP1B1 and FLAG-OATP1B3 in HEK293-FLAG-OATP1B1 and-OATP1B3 cells, such treatment did not affect the total protein levels of OATP1B1 and OATP1B3, suggesting that the UPS plays a minor role in degradation of OATP1B1 and OATP1B3 under current constitutive conditions. Pretreatment with bortezomib (50-250 nM, 2-7 h) significantly decreased transport of [3H]CCK-8, a specific OATP1B3 substrate, in HEK293-OATP1B3 and human sandwich-cultured hepatocytes (SCH). However, bortezomib pretreatment had negligible effects on the transport of [3H]E217βG and [3H]pitavastatin, dual substrates of OATP1B1 and OATP1B3, in HEK293-OATP1B1/1B3 cells and/or human SCH. Compared with vehicle control treatment, bortezomib pretreatment significantly decreased the maximal transport velocity (Vmax) of OATP1B3-mediated transport of CCK-8 (92.25 ± 14.2 vs. 133.95 ± 15.5 pmol/mg protein/min) without affecting the affinity constant (Km) values. Treatment with other proteasome inhibitors MG132, epoxomicin, and carfilzomib also significantly decreased OATP1B3-mediated [3H]CCK-8 transport. In summary, the current studies for the first time report ubiquitination of OATP1B1 and OATP1B3 and the apparent substrate-dependent inhibitory effect of bortezomib on OATP1B3-mediated transport. The data suggest that bortezomib has a low risk of causing OATP-mediated DDIs.

Novel hybrid composite discharge electrode for electrostatic precipitator

Over the last few decades, electrostatic precipitators (ESPs) have emerged as effective air pollution control devices for treating coal-fired power plant exhausts. Among the components of the ESP, the discharge electrodes are extremely important in determining the collection efficiency of the ESP. Typically, in wet ESPs, the discharge electrodes used must be made of corrosion-resistant alloys, which makes them extremely expensive and heavy. Hybrid composite discharge electrodes have the potential to be lightweight and corrosion-resistant substitute for traditional metal alloy electrodes used in wet ESPs. In this experimental study, a novel hybrid composite electrode (recently patented at Ohio University) is presented as a substitute for traditional metal electrodes in wet ESPs. The samples of hybrid electrodes were fabricated by using carbon fiber composites, combined with metal mesh, in the shape of a long and thin tape. The electrode's electrical response was evaluated in open atmospheric conditions, while connected to a transformer-rectifier unit to generate a corona current at voltages exceeding 50 kV. Results of these hybrid electrodes were compared with traditional metal electrodes. The hybrid composite discharge electrode produced a uniform corona at comparable power levels to that of metal electrodes, with additional advantages of being compact, lightweight, and highly corrosion resistant. In addition, hybrid composite electrodes exhibited lower corona onset voltage as compared with metal electrodes. The preliminary experimental data are encouraging and show significant potential for this new inexpensive hybrid electrode to replace metal electrodes in wet ESPs, providing comparable (and in some cases exceeding) collection efficiencies with lower ozone generation.

IMPLICATIONS

The newly invented hybrid composite electrode (HCE) performance was evaluated through experimentation with conventional metal electrodes. The HCE performance was comparable to the metal electrodes. The HCE also exhibited uniform corona fields and steady power while maintaining similar and in some cases superior electrical performance as compared with metal electrodes and thus shows a significant potential to substitute metal electrodes in wet ESP systems.

Experimental study of cross-flow wet electrostatic precipitator

This paper reports development and testing of a novel cross-flow wet electrostatic precipitator (WESP), recently patented at Ohio University, that utilizes vertical columns of permeable material in the form of polypropylene ropes placed in a cross-flow configuration within a flue gas stream. The cross-flow design has large surface area, which provides scrubbing action; therefore, it has the potential for removing multiple pollutants, including particulates, gases, vapors, and mists. In this new method, the ropes are kept wet by the liquid (water) introduced from the top of the cells running downward on the ropes by capillary action, making the permeable materials act as the ground electrode for capturing particles from the flue gas. Preliminary testing has shown an efficiency of well above 80% using two cells and three sets of discharge electrodes. Since the material of construction is primarily corrosion-resistant polymeric material, both weight and cost reductions are expected from this new design.

IMPLICATIONS

The newly invented cross-flow WESP exhibit particulate collection efficiency of well above 80% when introduced in particulate-laden exhaust flow. This value was obtained using a two cells and three discharge electrodes configuration. The electric field strength has a substantial effect on the collection efficiency. Also, the pressure drop test results indicate that there is a potential to increase the collection area, which, in turn, will increase the collection efficiency further.

In-vitro analysis of forces in conventional and ultrasonically assisted drilling of bone

BACKGROUND

Drilling of bone is widely performed in orthopaedics for repair and reconstruction of bone. Current paper is focused on the efforts to minimize force generation during the drilling process. Ultrasonically Assisted Drilling (UAD) is a possible option to replace Conventional Drilling (CD) in bone surgical procedures.

OBJECTIVE

The purpose of this study was to investigate and analyze the effect of drilling parameters and ultrasonic parameters on the level of drilling thrust force in the presence of water irrigation.

METHODS

Drilling tests were performed on young bovine femoral bone using different parameters such as spindle speeds, feed rates, coolant flow rates, frequency and amplitudes of vibrations.

RESULTS

The drilling force was significantly dropped with increase in drill rotation speed in both types of drilling. Increase in feed rate was more influential in raising the drilling force in CD compared to UAD. The force was significantly dropped when ultrasonic vibrations up to 10 kHz were imposed on the drill. The drill force was found to be unaffected by the range of amplitudes and the amount of water supplied to the drilling region in UAD.

CONCLUSIONS

Low frequency vibrations with irrigation can be successfully used for safe and efficient drilling in bone.

Downregulation of Organic Anion Transporting Polypeptide (OATP) 1B1 Transport Function by Lysosomotropic Drug Chloroquine: Implication in OATP-Mediated Drug-Drug Interactions

Organic anion transporting polypeptide (OATP) 1B1 mediates the hepatic uptake of many drugs including lipid-lowering statins. Decreased OATP1B1 transport activity is often associated with increased systemic exposure of statins and statin-induced myopathy. Antimalarial drug chloroquine (CQ) is also used for long-term treatment of rheumatoid arthritis and systemic lupus erythematosus. CQ is lysosomotropic and inhibits protein degradation in lysosomes. The current studies were designed to determine the effects of CQ on OATP1B1 protein degradation, OATP1B1-mediated transport in OATP1B1-overexpressing cell line, and statin uptake in human sandwich-cultured hepatocytes (SCH). Treatment with lysosome inhibitor CQ increased OATP1B1 total protein levels in HEK293-OATP1B1 cells and in human SCH as determined by OATP1B1 immunoblot. In HEK293-FLAG-tagged OATP1B1 stable cell line, co-immunofluorescence staining indicated that intracellular FLAG-OATP1B1 is colocalized with lysosomal associated membrane glycoprotein (LAMP)-2, a marker protein of late endosome/lysosome. Enlarged LAMP-2-positive vacuoles with FLAG-OATP1B1 protein retained inside were readily detected in CQ-treated cells, consistent with blocking lysosomal degradation of OATP1B1 by CQ. In HEK293-OATP1B1 cells, without pre-incubation, CQ concentrations up to 100 μM did not affect OATP1B1-mediated [(3)H]E217G accumulation. However, pre-incubation with CQ at clinically relevant concentration(s) significantly decreased [(3)H]E217G and [(3)H]pitavastatin accumulation in HEK293-OATP1B1 cells and [(3)H]pitavastatin accumulation in human SCH. CQ pretreatment (25 μM, 2 h) resulted in ∼1.9-fold decrease in Vmax without affecting Km of OATP1B1-mediated [(3)H]E217G transport in HEK293-OATP1B1 cells. Pretreatment with monensin and bafilomycin A1, which also have lysosome inhibition activity, significantly decreased OATP1B1-mediated transport in HEK293-OATP1B1 cells. Pharmacoepidemiologic studies using data from the U.S. Food and Drug Administration Adverse Event Reporting System indicated that CQ plus pitavastatin, rosuvastatin, and pravastatin, which are minimally metabolized by the cytochrome P450 enzymes, led to higher myopathy risk than these statins alone. In summary, the present studies report novel findings that lysosome is involved in degradation of OATP1B1 protein and that pre-incubation with lysosomotropic drug CQ downregulates OATP1B1 transport activity. Our in vitro data in combination with pharmacoepidemiologic studies support that CQ has potential to cause OATP-mediated drug-drug interactions.

Analysis of temperature in conventional and ultrasonically-assisted drilling of cortical bone with infrared thermography

BACKGROUND

Bone drilling is widely used in orthopaedics, dental and neurosurgeries for repair and fixation purposes. One of the major concerns in drilling of bone is thermal necrosis that may seriously affect healing at interfaces with fixtures and implants. Ultrasonically-assisted drilling (UAD) is recently introduced as alternative to conventional drilling (CD) to minimize invasiveness of the procedure.

OBJECTIVE

This paper studies temperature rise in bovine cortical bone drilled with CD and UAD techniques and their comparison using infrared thermography.

METHODS

A parametric investigation was carried out to evaluate effects of drilling conditions (drilling speed and feed rate) and parameters of ultrasonic vibration (frequency and amplitude) on the temperature elevation in bone.

RESULTS

Higher levels of the drilling speed and feed rate were found responsible for generating temperatures above a thermal threshold level in both types of drilling. UAD with frequency below 20 kHz resulted in lower temperature compared to CD with the same drilling parameters. The temperatures generated in cases with vibration frequency exceeding 20 kHz were significantly higher than those in CD for the range of drilling speeds and feed rates. The amplitude of vibration was found to have no significant effect on bone temperature.

CONCLUSIONS

UAD may be investigated further to explore its benefits over the existing CD techniques.

Experimental and numerical investigation of cracking behavior of cortical bone in cutting

BACKGROUND

Bone cutting is a well-known surgical procedure in orthopaedics and dentistry for fracture treatment and reconstruction. Common complications associated with the process are mechanical damage linked with excessive levels of penetration force. Larger forces may produce minor cracks in bone which may seriously affect strength of fixation and may delay the healing process.

OBJECTIVE

This paper investigates cracking behavior in the microstructure of cortical bone in cutting using experimental and numerical techniques.

METHODS

Experiments were performed on cortical bone to study the mechanics of crack propagation and evaluate the extent of crack with the drilling force and amount of penetration. Finite element (FE) simulations were performed to visualize the extension and arrest of the cracks in bone microstructure.

RESULTS

The length of crack was found to be strongly influenced by the drilling force and amount of drill penetration. Osteon were seen to deflect the cracks at their boundaries. Crack propagation in bone microstructure was observed to depend on anatomical direction. Numerical simulations predicted the direction of crack propagation and found osteon boundaries to act as barrier to the cracks.

CONCLUSIONS

Lower drilling force may be used in cutting the bone to avoid cracks in the bone tissue. A detailed FE model based on fracture data of cortical bone is to be produced to simulate cracking of bone microstructure.

Comparative study of conventional and ultrasonically-assisted bone drilling

BACKGROUND

Bone drilling is a well-known surgical procedure in orthopaedics and dentistry for fracture treatment and reconstruction. Advanced understanding of the mechanics of the drill-bone interaction is necessary to overcome challenges associated with the process and related postoperative complications.

OBJECTIVE

The aim of this study was to explore the benefits of a novel drilling technique, ultrasonically-assisted drilling (UAD), and its possible utilization in orthopaedic surgeries.

METHODS

The study was performed by conducting experiments to understand the basic mechanics of the drilling process using high speed filming of the drilling zone followed by measurements to quantify thrust force, surface roughness and cracking of the bone near the immediate vicinity of the hole with and without ultrasonic assistance.

RESULTS

Compared to the spiral chips produced during conventional drilling (CD), UAD was found to break the chips in small pieces which facilitated their fast evacuation from the cutting region. In UAD, lower drilling force and better surface roughness was measured in drilling in the radial and longitudinal axis of the bone. UAD produced crack-free holes which will enhance postoperative performance of fixative devices anchoring the bone.

CONCLUSIONS

UAD may be used as a possible substitute for CD in orthopaedic clinics.

Strengthening the Pharmacovigilance Programme in Nepal

The aims of pharmacovigilance are early recognition of previously unknown adverse drug reactions (ADRs), recognition of changes in frequency of known ADRs, identification of risk factors and mechanism of ADRs, quantitative analysis of benefit/risk ratio and dissemination of safety information for rational drug prescribing and regulation. The pharmacovigilance programme in Nepal is a recent development. The Department of Drug Administration (DDA) took the initiative to set up a pharmacovigilance program in 2002; however, it was initiated systematically only after two years. DDA acts as the National Pharmacovigilance Centre (NPC). It collects ADR case reports from the Regional Pharmacovigilance Centre (RPC). Currently there are six RPCs operating in the country. The current reporting trends suggest high under-reporting of suspected ADRs. This paper is a review of those studies which are focused on pharmacovigilance and healthcare professionals’ perspectives on ADR reporting in Nepal. It also recommends the possible ways to improve the ADR reporting based on the context of Nepal.DOI: http://dx.doi.org/10.3126/nje.v3i1.8286 Nepal Journal of Epidemiology 2013;3 (1): 230-235

A research methodology workshop on ‘Social issues in use of medicines’ – cooperation between institutions and participant feedback

A research methodology workshop on social issues in use of medicines was conducted at Pokhara, Nepal from December 21st to 24th, 2008. The present study was conducted to obtain detailed participant feedback about the workshop and obtain suggestions for improvement. The participants’ knowledge was assessed at the start of the workshop and on the final day by noting their agreement with a set of 40 statements using a modified Likert-type scale. The areas of qualitative research, statistics, research methodology, drug use, pharmacovigilance, journal and general were covered. Certain statements were negative and their scores were reversed. The total score was calculated. The median total scores were compared among various subgroups of respondents. Session evaluation was done at the end of each session. A total of twenty-five participants attended the sessions. The workshop significantly improved the median total scores. Significant improvements were also seen in the subcategories Statistics and Journal. The scores of certain statements were low. The evaluation scores of certain sessions were low. The overall participant opinion about the workshop was positive. Occasional problems with accent of the facilitator and lack of internet access were major problems noted. Some participants felt the workshop was too hectic. Journal of College of Medical Sciences-Nepal,2012,Vol-8,No-1, 60-67 DOI: http://dx.doi.org/10.3126/jcmsn.v8i1.6829