Novel Presentation of Major Histocompatibility Complex Class II Deficiency with Hemophagocytic Lymphohistiocytosis

PURPOSE

Major histocompatibility complex (MHC) class II deficiency is one of the combined immune deficiency disorders caused by defects in the MHC class II regulatory genes leading to abnormal T cells development and function. Therefore, patients mainly present with increased susceptibility to infections, diarrhea, and failure to thrive. In this report, we present one MHC class II deficient patient with a novel presentation with Hemophagocytic Lymphohistiocytosis (HLH).

METHODS

Immunophenotyping of lymphocyte subpopulations and HLA-DR expression was assess by flow cytometry. Gene mutational analysis was performed by whole exome and Sanger sequencing.

RESULTS

We reported a 7-year-old girl, who was diagnosed at age of 2 years with MHC class II deficiency by genetic testing and flow cytometry. Two years later, she developed disseminated BCGitis which was treated with proper antimicrobial agents. At the age of 7 years, she presented with clinical features fulfilling 6 diagnostic criteria of HLH including evidence of hemophagocytic activity in bone marrow aspiration. Accordingly, the diagnosis of HLH was established and the patient was started on IV Dexamethasone, Anakinra and IVIG. Eventually, patient started to improve and was discharged in good condition. Few months later, the patient was readmitted with severe pneumonia and sepsis leading to death.

CONCLUSION

Patients with MHC class II deficiency might present with disseminated BCGitis especially if the patient has severe T cell lymphopenia. Additionally, this immune defect might be added to the list of inborn errors of immunity that can be complicated with HLH.

Nanomaterials Connected to Bioreceptors to Introduce Efficient Biosensing Strategy for Diagnosis of the TORCH Infections: A Critical Review

TORCH infection is a significant risk factor for severe fetal damage, especially congenital malformations. Screening pregnant women for TORCH pathogens could reduce the incidence of adverse pregnancy outcomes and prevent birth defects. Hence, timely identification and inhibition of TORCH infections are effective ways to successfully prevent them in pregnant women. Recently, the superiority of biosensors in TORCH pathogen sensing has been emphasized due to their intrinsic benefits, such as rapid response time, portability, cost-effectiveness, much friendlier preparation and determination steps. With the introduction of advanced nanomaterials into biosensing, the diagnostic properties of biosensors have significantly improved. This study core presents and debates the current progress in biosensing systems for TORCH pathogens using various artificial and natural receptors. The incorporation of nanomaterials into various transduction systems can enhance diagnostic performance. The key performance characteristics of optical and electrochemical biosensors, such as response time, limit of detection (LOD), and linear detection range, are systematically discussed, along with the current TORCH pathogens used for constructing biosensors. Finally, the major problems that exist for converting scientific investigation into product development are also outlined.

Current status and prospects for improved targeted delivery approaches for cancer

Millions of individuals worldwide suffer from the complicated disease known as cancer. Though they frequently have serious side effects and can harm healthy cells, the current cancer treatments, such as radiation therapy and chemotherapy, are effective in many cases. Targeted drug delivery systems have emerged as a promising new paradigm in cancer treatment because they can deliver drugs directly to cancer cells with minimal harm to healthy cells. This review aims to give a broad overview of the state of targeted drug delivery systems for cancer treatment and investigate the technology's potential in the future. We'll go through the various kinds of targeted drug delivery systems, their drawbacks, the most recent developments, and possible future paths for further study and creation. This review aims to provide an overview of the current status of targeted drug delivery systems for cancer treatment, including the different types of targeted drug delivery systems, their limitations, recent advancements, and potential future directions for research and development. By examining the field's current state and exploring prospects, this review aims to highlight the potential of targeted drug delivery systems for improving cancer treatment and ultimately enhancing patient outcomes.

Traumatic lumbar disc herniation: A systemic case review and meta-analysis

Introduction

Traumatic lumbar disc herniation (TLDH) without fracture in the in-situ motion segment is a rare occurrence compared with degenerative herniation.

Research question

This study provides a systematic discussion of various aspects related to the diagnosis of TLDH.

Material and methods

This review includes 12 cases of TLDH with MR-images since 2009 published in the PubMed and one adjunct illustration. The cases were categorized into two groups for a comprehensive analysis, TLDH with or without in-situ segment fracture. Additionally, we reported a case of a 43-year-old female patient with a recent stenosing TLDH at L5/S1, accompanied by a large sequestration (disc herniation stage-4, and Michigan State University Classification: MSU 3-AB) and an endplate compression fracture at L2 (AO A1).

Results

Isolated traumatic lumbar disc herniation is possible, but it is required exclude cases with fractures in the in-situ motion segment.

Discussion and conclusion

Trauma with related injury mechanisms is the highest priority for the diagnosis of TLDH. Low-grade disc degeneration without significant instability could be accepted for diagnosing TLDH. A TLDH on MR images might show a slightly lower T2-signal compared to the CSF and a homogeneous T1-signal like the spinal cord, as well as a similar STIR-signal of the sequestration and CSF. If necessary, a histological examination could be performed to evaluate the degenerative changes in the injured disc, especially to assist the evaluation due to legal reasons.

Atovaquone exerts its anticancer effect by inhibiting Na+/K+-ATPase ion transport in canine cancer cells

Background and Aim

New anticancer drugs are being developed to avoid the toxicity and chemoresistance of the currently available drugs. The Food and Drug Administration-approved anti-malarial drug atovaquone is known to act as a selective oxidative phosphorylation inhibitor in the mitochondria by competing with CO Q10 (mitochondrial complex II and III). This study aimed to investigate the effect of atovaquone by examining the Na+/K+-ATPase (NKA) activity in various canine cell lines.

Materials and Methods

Canine cell lines were treated with various concentrations (2.5, 5, 10, 15, and 20 μM) of atovaquone for 24, 48, and 72 h. Human cell lines were used as a control to validate the canine cancer cell lines. The activities of the drugs against the cancer cell lines were measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromideassay. The cell metabolic activity was determined by measuring the activities of the nicotinamide adenine dinucleotide phosphate-dependent cellular oxidoreductase enzymes. The NKA activity was measured using the single-cell patch clamping assay.

Results

Atovaquone-induced apoptosis by elevating the concentration of reactive oxygen species (ROS) in the tumor cells, leading to cell death. Treatment of canine cancer cells with N-acetylcysteine (ROS inhibitor) reduced the activity of the drug. Furthermore, atovaquone inhibited more than 45% of the NKA ion current.

Conclusion

This study demonstrated effects of atovaquone against canine cancer cell lines. The data may prove beneficial in repurposing the drug as a new anticancer agent in canine clinical trials, which might aid in fighting human cancer.

COVID-19 in Pediatric Patients: A Study Based on Biomarker Levels

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected people of all ages, but limited data are available on children with mild and severe coronavirus disease 2019 (COVID-19).

METHODS

Clinical characteristics, inflammation, and other biochemical biomarkers have been described, but information is scarce in asymptomatic and mild cases. Laboratory investigations were performed with pediatric patients (n=70) for liver function and kidney function, along with C-reactive protein (CRP).

RESULTS

Mild clinical characteristics and symptoms were observed in pediatric patients. Even in moderate cases of COVID-19, elevated levels of biomarkers indicate altered liver and kidney function in children. The levels of liver enzymes, bilirubin, creatinine, and CRP varied significantly between the three classes, particularly between asymptomatic and moderate cases. Liver enzymes, bilirubin, and creatinine levels in moderate COVID-19 pediatric cases were twice as elevated as in asymptomatic cases. Liver enzymes and CRP levels were moderately elevated.

CONCLUSION

Monitoring blood biomarkers consistently can assist in the accurate identification of infection in young patients as well as in the prevention of its spread and the administration of appropriate treatment.

Sound-Based Localization Using LSTM Networks for Visually Impaired Navigation

In this work, we developed a prototype that adopted sound-based systems for localization of visually impaired individuals. The system was implemented based on a wireless ultrasound network, which helped the blind and visually impaired to navigate and maneuver autonomously. Ultrasonic-based systems use high-frequency sound waves to detect obstacles in the environment and provide location information to the user. Voice recognition and long short-term memory (LSTM) techniques were used to design the algorithms. The Dijkstra algorithm was also used to determine the shortest distance between two places. Assistive hardware tools, which included an ultrasonic sensor network, a global positioning system (GPS), and a digital compass, were utilized to implement this method. For indoor evaluation, three nodes were localized on the doors of different rooms inside the house, including the kitchen, bathroom, and bedroom. The coordinates (interactive latitude and longitude points) of four outdoor areas (mosque, laundry, supermarket, and home) were identified and stored in a microcomputer's memory to evaluate the outdoor settings. The results showed that the root mean square error for indoor settings after 45 trials is about 0.192. In addition, the Dijkstra algorithm determined that the shortest distance between two places was within an accuracy of 97%.

Slotted Monopole Patch Antenna for Microwave-Based Head Imaging Applications

A modified monopole patch antenna for microwave-based hemorrhagic or ischemic stroke recognition is presented in this article. The designed antenna is fabricated on a cost-effective FR-4 lossy material with a 0.02 loss tangent and 4.4 dielectric constant. Its overall dimensions are 0.32 λ × 0.28 λ × 0.007 λ, where λ is the lower bandwidth 1.3 GHz frequency wavelength. An inset feeding approach is utilized to feed the antenna to reduce the input impedance (z = voltage/current). A total bandwidth (below -10 dB) of 2.4 GHz (1.3-3.7 GHz) is achieved with an effective peak gain of over 6 dBi and an efficiency of over 90%. A time-domain analysis confirms that the antenna produces minimal signal distortion. Simulated and experimental findings share a lot of similarities. Brain tissue is penetrated by the antenna to a satisfactory degree, while still exhibiting a safe specific absorption rate (SAR). The maximum SAR value measured for the head model is constrained to be equal to or below 0.1409 W/kg over the entire usable frequency band. Evaluation of theoretical and experimental evidence indicates the intended antenna is appropriate for Microwave Imaging (MWI) applications.

Time Window for Acute Stroke Treatment: Current Practice in King Abdullah Medical City Specialist Hospital in Makkah, Saudi Arabia

Introduction

Stroke has become one of the most severe causes of long-term neurological impairment and disability and is considered one of the leading causes of mortality worldwide. This study aimed to determine time delays in stroke patients from symptoms onset to treatment with tissue plasminogen activator (tPA) initiation in King Abdullah Medical City Specialist Hospital, Makkah, Saudi Arabia.

Patients and methods

We reviewed 81 patients who suffered from acute stroke. The data were collected from patients’ electronic and paper files. Patients were divided into two main categories based on interval time from recognition of symptoms to tPA treatment. Patients were divided into early treatment, if the duration was less than or equal to 120 minutes, and delayed treatment, if the interval time was more than 120 minutes.

Results

Nearly two-thirds (64.2%) were males, and more than half (5.6%) were in the older age group (>65 years). Patients who underwent thrombectomy were 7.4%. The mean value of the National Institutes of Health Stroke Scale (NIHSS) score was 10.7 (SD: 7.14). The mean time from symptoms onset to arrival at the hospital was 82.4 (SD: 44.1) minutes, while the total time from recognition of symptoms to tPA treatment was 154 (SD: 50.8) minutes. The prevalence of patients with delayed treatment was 72.8%, and the rest were assumed to have early treatment (27.2%). None of the socio-demographic variables were predicted to influence delayed treatment.

Conclusion

A significant number of patients were delayed in treatment. Patients' socio-demographic data and NIHSS scores seem to have no significant effect on delayed treatment. Further research is needed to establish the delay in time for pre-hospital and in-hospital treatment of stroke patients.

A varying-radius cable equation for the modelling of impulse propagation in excitable fibres

In this study, we present a varying-radius cable equation for nerve fibres taking into account the varying diameter along the neuronal segments. Finite element neuronal models utilising the classical (fixed-radius) and varying-radius cable formulations were compared using simple and realistic morphologies under intra- and extracellular electrical stimulation protocols. We found that the use of the classical cable equation to model intracellular neural electrical stimulation exhibited an error of 17% in a passive resistive cable model with abrupt change in radius from 1 to 2 μm, when compared to the known analytical solution and varying-radius cable formulation. This error was observed to increase substantially using more realistic neuron morphologies and branching structures. In the case of extracellular stimulation however, the difference between the classical and varying-radius formulations was less pronounced, but we expect this difference will increase under more complex stimulation paradigms such as high-frequency stimulation. We conclude that for computational neuroscience applications, it is essential to use the varying-radius cable equation for accurate prediction of neuronal responses under electrical stimulation.

Fluid structure computational model of simulating mitral valve motion in a contracting left ventricle

BACKGROUND

Fluid structure interaction simulations h hold promise in studying normal and abnormal cardiac function, including the effect of fluid dynamics on mitral valve (MV) leaflet motion. The goal of this study was to develop a 3D fluid structure interaction computational model to simulate bileaflet MV when interacting with blood motion in left ventricle (LV).

METHODS

The model consists of ideal geometric-shaped MV leaflets and the LV, with MV dimensions based on human anatomical measurements. An experimentally-based hyperelastic isotropic material was used to model the mechanical behaviour of the MV leaflets, with chordae tendineae and papillary muscle tips also incorporated. LV myocardial tissue was prescribed using a transverse isotropic hyperelastic formulation. Incompressible Navier-Stokes fluid formulations were used to govern the blood motion, and the Arbitrary Lagrangian Eulerian (ALE) method was employed to determine the mesh deformation of the fluid and solid domains due to trans-valvular pressure on MV boundaries and the resulting leaflet movement.

RESULTS

The LV-MV generic model was able to reproduce physiological MV leaflet opening and closing profiles resulting from the time-varying atrial and ventricular pressures, as well as simulating normal and prolapsed MV states. Additionally, the model was able to simulate blood flow patterns after insertion of a prosthetic MV with and without left ventricular outflow tract flow obstruction. In the MV-LV normal model, the regurgitant blood flow fraction was 10.1 %, with no abnormality in cardiac function according to the mitral regurgitation severity grades reported by the American Society of Echocardiography.

CONCLUSION

Our simulation approach provides insights into intraventricular fluid dynamics in a contracting LV with normal and prolapsed MV function, as well as aiding in the understanding of possible complications after transcatheter MV implantation prior to clinical trials.

Level of Self-Perceived Knowledge Regarding Oral and Maxillofacial Surgery and Dental Surgery among Dental Undergraduates and Graduates in Saudi Arabia

For evaluating the level of self-confidence of dental undergraduate, graduates and postgraduates regarding Oral and Maxillofacial Surgery and Dental Surgery (OMFS and DS) and to assess the teaching curriculum at Saudi Dental Institutes using a validated modified survey form developed by the Association of British Academic and Oral Maxillofacial Surgeons (ABAOMS). The undergraduate students (level 11 and 12), graduates and postgraduates with more than two years of experience after completing education from Saudi Arabian Dental Institutes responded to the questions of modified ABAOMS survey form assessing various areas of OMFS and DS curriculum. It was a cross-sectional study, conducted in Saudi Arabia from June 2021 to September 2021. In order to assess the difference between the respondents independent sample t-test was applied. Further to evaluate the correlation between confidence levels for carrying out OMFS and DS procedures and curriculum Spearman's rho test was applied. Majority of the respondents in these three groups expressed of having sufficient knowledge to undertake their own clinical practice. In general the responses were favorable except for the low confidence level in performing minor surgical procedures. It can be concluded from the responses to modified ABAOMS questionnaire displayed the level of confidence in taking independent clinical practice, carrying out minor oral surgical procedures and identifying malignant and non-malignant lesions. Respondents of all three levels felt comfortable in extractions using the surgical forceps or elevators, removal of broken down roots, and recognizing the potentially malignant and malignant lesions of the human oral cavity.

Cardiovascular Diseases Diagnosis by Impedance Cardiography

Cardiovascular disease (CVD) represents the leading cause of mortality worldwide. In order to diagnose CVDs, there are a range of detection methods, among them, the impedance cardiography technique (ICG). It is a non-invasive and low-cost method. In this paper, we highlight recent advances and developments of the CDVs diagnosis mainly by the ICG method. We considered papers published during the last five years (from 2017 until 2022). Based on this study, we expressed the need for an ICG database for the different CDVs.

The Natural Product β-Escin Targets Cancer and Stromal Cells of the Tumor Microenvironment to Inhibit Ovarian Cancer Metastasis

Simple Summary

β-escin, a component of horse chestnut seed extract, was first identified as an inhibitor of ovarian cancer (OvCa) adhesion/invasion in our high-throughput screening program using a three-dimensional organotypic model assembled from primary human cells and extracellular matrix. The goal of the study presented here is to determine if β-escin and structurally-similar compounds have a therapeutic potential against OvCa metastasis. β-escin and cardiac glycosides inhibit ovarian cancer adhesion/invasion to the omental microenvironment in vivo, and β-escin inhibits ovarian cancer metastasis in the prevention and intervention setting. Additionally, β-escin was found to decrease the stemness of ovarian cancer cells, inhibit extracellular matrix production in the tumor microenvironment, and inhibit HIF1α stability in ovarian cancer cells and the tumor microenvironment. This study reveals that the natural compound β-escin has therapeutic potential because of its ability to prevent OvCa dissemination by targeting both cancer and stromal cells in the OvCa tumor microenvironment.

Abstract

The high mortality of OvCa is caused by the wide dissemination of cancer within the abdominal cavity. OvCa cells metastasize to the peritoneum, which is covered by mesothelial cells, and invade into the underlying stroma, composed of extracellular matrices (ECM) and stromal cells. In a study using a three-dimensional quantitative high-throughput screening platform (3D-qHTS), we found that β-escin, a component of horse chestnut seed extract, inhibited OvCa adhesion/invasion. Here, we determine whether β-escin and structurally similar compounds have a therapeutic potential against OvCa metastasis. Different sources of β-escin and horse chestnut seed extract inhibited OvCa cell adhesion/invasion, both in vitro and in vivo. From a collection of 160 structurally similar compounds to β-escin, we found that cardiac glycosides inhibited OvCa cell adhesion/invasion and proliferation in vitro, and inhibited adhesion/invasion and metastasis in vivo. Mechanistically, β-escin and the cardiac glycosides inhibited ECM production in mesothelial cells and fibroblasts. The oral administration of β-escin inhibited metastasis in both OvCa prevention and intervention mouse models. Specifically, β-escin inhibited ECM production in the omental tumors. Additionally, the production of HIF1α-targeted proteins, lactate dehydrogenase A, and hexokinase 2 in omental tumors was blocked by β-escin. This study reveals that the natural compound β-escin has a therapeutic potential because of its ability to prevent OvCa dissemination by targeting both cancer and stromal cells in the OvCa tumor microenvironment.

Clinical characteristics and predictors of mortality among COVID-19 patients in Saudi Arabia

BACKGROUND

The new coronavirus disease (COVID-19) has caused more than 1.8 million deaths, with a fatality rate of 2.5% in more than 200 countries as of January 4, 2021. Analysis of COVID-19 clinical features can help predict disease severity and risk of mortality, early identification of high-risk patients, and provide knowledge to inform clinical interventions.

OBJECTIVE

The purpose of this study is to investigate the clinical characteristics and possible predictors associated with mortality in patients with COVID-19 admitted to King Fahad (KFH), Ohood, and Miqat hospitals in Madina, Saudi Arabia.

METHODS

This retrospective observational study to investigate the clinical characteristic and possible predictors associated with mortality for those 119 mild, moderate, or critically ill patients confirmed by laboratory results to have COVID-19 who were admitted to three hospitals in Madina, Saudi Arabia, from March 25, 2020, to July 30, 2020. Data were collected from December 1, 2020, to December 14, 2020.

RESULTS

Of the 119 patients included in the study, the mean age was 54.2 (±15.7) years, with 78.2% survivors and 21.8% non-survivors. The demographic analysis indicated that the likelihood of mortality for patients in the older age group (i.e., ≥65 years) was five times higher than those in the younger age group (OR = 5.34, 95% CI 1.71-16.68, p = 0.004). The results also indicated those patients who admitted to the intensive care unit (ICU) was approximately seven times higher odds of mortality compare with those who were not admitted (OR = 6.48, 95% CI 2.52-16.63, p < 0.001). In addition, six laboratory parameters were positively associated with the odds of mortality: white blood cell count (OR = 1.11, 95% CI 1.02-1.21, p = 0.018), neutrophil (OR = 1.11, 95% CI 1.02-1.22, p = 0.020), creatine kinase myocardial band (OR = 1.02, 95% CI 1.00-1.03, p = 0.030), C-reactive protein (OR = 1.01, 95% CI 1.00-1.01, p = 0.002), urea (OR = 1.06, 95% CI 1.01-1.11, p = 0.026), and lactate dehydrogenase (OR = 1.00, 95% CI 1.00-1.01, p = 0.020).

CONCLUSIONS

In this cohort, COVID-19 patients within the older age group (≥65 years) admitted to the ICU with increased C-reactive protein levels in particular, were associated with increased odds of mortality. Further clinical observations are warranted to support these findings and enhance the mapping and control of this pandemic.

Electrical Impedance Tomography - Recent Applications and Developments

Electrical impedance tomography (EIT) is a low-cost noninvasive imaging method. The main purpose of this paper is to highlight the main aspects of the EIT method and to review the recent advances and developments. The advances in instrumentation and in the different image reconstruction methods and systems are demonstrated in this review. The main applications of the EIT are presented and a special attention made to the papers published during the last years (from 2015 until 2020). The advantages and limitations of EIT are also presented. In conclusion, EIT is a promising imaging approach with a strong potential that has a large margin of progression before reaching the maturity phase.

Comparison Between the Impact of Vasopressors and Goal-Directed Fluid Therapy on the Management of Free Flap Reconstruction of Head and Neck and Monitoring in ICU

Head and neck reconstructions are often accompanied with complex long surgical procedures. Free flap tissue transfer is a standard reconstruction method that reestablishes severe tissue defects after resection due to trauma or cancer. Imbalanced fluid resuscitation can extremely harm the outcome of the flap either due to hypoperfusion or edema. Flap-related postoperative complications mainly flap failure necessitates the administration of a large amount of intravenous fluids perioperatively especially with lengthy operative time. Therefore, vasopressors may be used to preserve hemodynamic stability without excessive fluids use. Nevertheless, these vasopressors have long been disfavored as they may provoke anastomosis vasoconstriction leading to graft hypoperfusion and finally flap failure. However, according to recent guidelines, they are now well-thought to be safe. Of note, inotropes have been confirmed to increase blood flow in the anastomosis hence they can replace vasoconstrictors. Recently, goal-directed fluid therapy (GDFT) has been proven to be excellent in high-risk head and neck free tissue transfer surgery as it decreases prolonged intensive care unit (ICU) admission hospitalization and complication rate. Today, GDFT is highly suggested as one of the enhanced recoveries after surgery protocols for major head and neck free flap reconstruction surgery.

Oxidative stress induced by the anti-cancer agents, plumbagin, and atovaquone, inhibits ion transport through Na+/K+-ATPase

Oxidative stress inhibits Na⁺/K⁺-ATPase (NKA), the ion channel that maintains membrane potential. Here, we investigate the role of oxidative stress-mediated by plumbagin and atovaquone in the inhibition of NKA activity. We confirm that plumbagin and atovaquone inhibit the proliferation of three human (OVCAR-3, SKOV-3, and TYKNu) and one mouse (ID8) ovarian cancer cell lines. The oxygen radical scavenger, N-acetylcysteine (NAC), attenuates the chemotoxicity of plumbagin and atovaquone. Whole-cell patch clamping demonstrates that plumbagin and atovaquone inhibit outward and the inward current flowing through NKA in SKOV-3 and OVCAR-3. Although both drugs decrease cellular ATP; providing exogenous ATP (5 mM) in the pipet solution used during patch clamping did not recover NKA activity in the plumbagin or atovaquone treated SKOV-3 and OVCAR-3 cells. However, pretreatment of the cells with NAC completely abrogated the NKA inhibitory activity of plumbagin and atovaquone. Exposure of the SKOV-3 cells to either drug significantly decreases the expression of NKA. We conclude that oxidative stress caused by plumbagin and atovaquone degrades NKA, resulting in the inability to maintain ion transport. Therefore, when evaluating compounds that induce oxidative stress, it is important to consider the contribution of NKA inhibition to their cytotoxic effects on tumor cells.

Abstract B36: Antimalarial agent, atovaquone, inhibits cancer cell proliferation by targeting oxidative phosphorylation and is a candidate for chemoprevention and chemotherapy of ovarian cancer

Atovaquone is a FDA-approved antimalarial agent that has also shown potent anticancer properties. In the current study, we demonstrate that atovaquone is a prime candidate for treatment of high-grade serous ovarian cancer. We have tested atovaquone against a panel of ovarian cancer cells lines and shown that this drug inhibits proliferation and induces apoptosis at IC50 concentrations between 10-20 microM. Exposure to atovaquone results in increased apoptosis as indicated by an increase in cleaved caspase 3 and other relevant apoptotic markers. Additionally, our data also suggest that atovaquone is able to reactivate p53. Inhibition of p53 attenuates the cytotoxicity of atovaquone. However, the primary event that occurs in atovaquone-treated cells is the rapid surge in intracellular oxygen radicals. Imaging cytometry experiments conclusively demonstrate that the oxygen radical surge originates in the mitochondria. The oxidative stress caused by atovaquone is responsible for DNA damage and p53 activation. The atovaquone-induced oxygen radical surge also leads to damage to the Na+/K+-ATPase, perturbing the ability of the cancer cells to maintain an optimal membrane potential. This increase in oxygen radicals occurs because atovaquone targets the oxidative phosphorylation pathway in the mitochondria and blocks electron transport. Measurements conducted on the Seahorse analyzer show decreased consumption of oxygen and lower levels of ATP in the atovaquone-treated cells. In the malarial parasite, atovaquone targets mitochondrial complex III. In ovarian cancer cells, supplying succinate did not reverse atovaquone-induced inhibition of oxidative phosphorylation. On the other hand, when cells were supplemented with the substrate for complex IV, the oxygen consumption rate normalized in atovaquone-exposed cells. These experiments suggest that atovaquone is likely inhibiting complex I-III of mitochondria. Atovaquone is a naphthoquinone with significant structural similarity with the electron transporter ubiquinone. In silico modeling experiments indicate that atovaquone can bind to the ubiquinone binding pocket on complexes I-III. Based on these experiments, we propose that atovaquone is competing with ubiquinone to inhibit efficient electron transport and thereby increasing the intracellular oxygen radicals. Ovarian tumor-bearing mice tolerated prolonged treatment with Mepron®, the clinical formulation of atovaquone. Daily treatment of ID8 tumor-bearing C57BL/6 mice with atovaquone for 3-4 weeks resulted in a significant decrease in tumor growth. Additionally, we also show decreased proliferation of human ovarian tumors treated ex vivo with atovaquone. These experiments indicate that atovaquone can be used as a safe and effective drug for chemoprevention and chemotherapy of ovarian tumors.

Citation Format: Arvinder Kapur, Mildred Felder, Yousef Alharbi, Allegra Cappuccini, Bikash Pattnaik, Lisa Barroilhet, Manish Patankar. Antimalarial agent, atovaquone, inhibits cancer cell proliferation by targeting oxidative phosphorylation and is a candidate for chemoprevention and chemotherapy of ovarian cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr B36.

Abstract NT-103: TARGETING OVARIAN TUMORS WITH OXPHOS INHIBITORS

Aerobic glycolysis is an important metabolic adaptation in tumors. However, there is mounting evidence that oxidative phosphorylation (OXPHOS) also contributes to metabolism in cancer cells. Therefore, agents targeting OXPHOS can serve as novel anticancer agents. We will present data on small molecule agents that inhibit the proliferation of ovarian and other cancer cells by inhibiting mitochondrial electron transport. We have focused our attention on citral, plumbagin, curcumin, cinnamaldehyde, piperlongumine, perillaldehyde, nonenal and other naturally occurring agents. All of these molecules share a common molecular epitope, the unsaturated carbonyl that participates in redox reactions. Cancer cells treated with these agents show a marked decrease in oxygen consumption rate and an increase in extracellular acidification. The redox ratio (NADH/FAD) and cellular ATP levels also decrease in response to these small molecule agents. In our search for additional and more potent OXPHOS inhibitors we have discovered that the FDA-approved anti-malarial drug atovaquone is an efficient inhibitor of electron transport in ovarian cancer cells. Chronic administration of atovaquone decreases the growth of ID8 tumors in C57BL/6 mice. Investigation in to the mechanism of action of the unsaturated carbonyl compounds indicates that their initial effect in cancer cells is the immediate and substantial rise in oxygen radicals as a result of OXPHOS inhibition. This increase in reactive oxygen causes extensive oxidative damage leading to DNA strand breaks. Subsequently, we have observed activation of p53-mediated apoptosis. These experiments are suggesting that inhibition of OXPHOS and the subsequent increase in intracellular oxygen radicals can result in the reactivation of the tumor suppressive responses of at least a subset of the p53 mutants. Additionally, our studies also indicate that the oxidative stress occurring as a result of OXPHOS inhibition directly leads to inhibition of ion transport through the Na+/K+-ATPase. As a result of this inhibition, cancer cells are unable to maintain a normal membrane potential. Studies are currently underway to determine if the inability to maintain membrane potential also contributes to apoptotic cancer cell death induced by these unsaturated carbonyl-containing compounds. Oxidative stress caused by these compounds leads to an increase in superoxide dismutase, catalase and glutathione synthesis via the activation of Nrf-2. Inhibition of Nrf-2 results in an increase in the potency of the unsaturated carbonyl compounds. We are therefore examining Nrf-2 increase as a form of chemoresistance mechanism that likely impinges on the anti-cancer activity of the unsaturated carbonyl compounds. These studies are allowing us to develop medicinal chemistry-based approaches to develop novel molecules with increased potency and targetability as OXPHOS inhibitors for the treatment of ovarian cancer.

Citation Format: Arvinder Kapur, Amruta Nayak, Mildred Felder, Allegra Cappucini, Spencer Ericksen, Yousef Alharbi, Bikash Pattnaik, Lisa Barroilhet, and Manish S. Patankar. TARGETING OVARIAN TUMORS WITH OXPHOS INHIBITORS [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr NT-103.

Abstract 891: Plumbagin and atovaquone inhibit Na+/K+-ATPase through the generation of oxidative stress

Plumbagin and atovaquone are chemotoxic to ovarian, breast and other tumors. Both molecules inhibit oxidative phosphorylation causing a rapid increase in intracellular oxygen radicals and apoptosis. Oxidative stress is also known to inhibit the activity of Na+/K+-ATPase (NKA), the ion channel that maintains the membrane potential. Here, we investigate if the oxidative stress mediated by plumbagin and atovaquone also leads to inhibition of NKA activity. We confirm that plumbagin and atovaquone inhibit proliferation of three human (OVCAR-3, SKOV-3 and TYKNu) and one mouse (ID8) ovarian cancer cell lines. Using SKOV-3 and OVCAR-3 as models for ovarian cancer, we demonstrate that oxygen radical scavenger, N-acetylcysteine (NAC) attenuated the cytotoxicity of plumbagin and atovaquone. Using whole cell patch clamping we demonstrate that plumbagin and atovaquone inhibit outward and inward current flowing through NKA in SKOV-3 and OVCAR-3. Both drugs decrease cellular ATP. Providing exogenous ATP (5 mM) in the pipet solution used during patch clamping did not recover NKA activity in the plumbagin or atovaquone treated SKOV-3 and OVCAR-3 cells. However, pretreatment of the cells with NAC completely abrogated the NKA inhibitory activity of plumbagin and atovaquone. Exposure of the SKOV-3 cells to either of the drugs for 1-2 h resulted in a significant decrease in the expression of NKA. We conclude that oxidative stress caused by plumbagin and atovaquone degrades NKA and hence the membrane potential cannot be optimally maintained. Evaluation of compounds that induce oxidative stress should therefore consider contribution of NKA inhibition to the cytotoxic activity of such agents.

Citation Format: Yousef Alharbi, Arvinder Kapur, Mildred Felder, Lisa Barroilhet, Bikash Pattnaik, Manish S. Patankar. Plumbagin and atovaquone inhibit Na+/K+-ATPase through the generation of oxidative stress [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 891.

Level of awareness and attitudes toward epilepsy in Qassim, Saudi Arabia: A cross-sectional study

OBJECTIVES

Reports of poor knowledge about epilepsy in different cities of Saudi Arabia have emphasized the need for a similar study of this issue in the Qassim region. Therefore, we aimed to determine the level of awareness and attitudes toward epilepsy in the population of Qassim, Saudi Arabia.

METHOD

A cross-sectional study was conducted in the Qassim region. A valid pretested questionnaire was distributed among Qassim residents in public places, such as malls, mosques, and parks. The sample size consisted of 3800 people from multiple cities in the Qassim region. The study was approved by the Qassim committee in Qassim University, and verbal consent was obtained from participants.

RESULTS

Data were obtained from 2253 males (59.3%) and 1544 females (40.6%). A large number of respondents were between 15 and 30 years (59.7%). The data showed that 85.5% of people had heard about epilepsy or read about it and 33% knew a patient with epilepsy while 42.7% had seen or witnessed someone having a seizure. It was also found that 73.2% of parents would allow their child to play with patients with epilepsy, 35.7% would allow their son or daughter to marry a patient with epilepsy, and 74.9% think that patients with epilepsy can be employed in jobs, like other people.

CONCLUSION

Insufficient knowledge about epilepsy, which is a very common disorder, has a great and negative impact on people with epilepsy, their families and communities, and the healthcare systems. In our study, we found that good knowledge was associated with being a young adult, male, unmarried, and being a university student.

Abstract B11: Antibody-conjugated cardiac glycosides: Potent agents for treatment of ovarian cancer

Cardiac glycosides (CG) are potent inhibitors of Na+/K+-ATPase (NKA), inducing apoptosis through the inhibition of ion current. We developed a synthetic CG, CEN09-106, with enhanced cytotoxic potential over conventional CGs such as oubain and others. For specific delivery to the tumor, CEN09-106 was conjugated through a stable chemical linker to antibodies targeted against cell surface proteins that form complexes with NKA. Due to this molecular design CEN09-106 is locally presented to the tumor and inhibits NKA activity. Internalization of CEN09-106 is not required for its cytotoxicity, and hence we refer to this family of antibody-CG complexes as extracellular drug conjugates (EDC). Ovarian tumors overexpress FXYD5, a modulator of NKA activity. We have developed EDC1 to target FXYD5. Here, we demonstrate the ability of EDC1 to target ovarian tumors and confirm its mechanism of action. First, we compared the activity of oubain, CEN09-106, and EDC1 in cell viability assays. While the potency of oubain was approximately 1-10 mM, CEN09-106 and EDC1 both had IC50 between 1-2.5 nM when tested against OVCAR-5, OV2008, and SKOV3 cells. Expression of FXYD5 in these cell lines was confirmed by flow cytometry. The inhibition of cell viability was attributed to apoptosis induced by CEN09-106 and EDC1 as measured by increase in cleaved caspase3 and annexin V binding and decrease in Bcl-2 expression. CEN09-106 and EDC1 also inhibited viability of the cisplatin-resistant C13 (IC50 ~2.5 nM) cells. Whole-cell patch-clamp recording of cancer cells revealed NKA ionic current in SKOV-3 and OV2008 cells after inhibition of majority of the cell surface ion transporters and channels. Outward ion current detected in SKOV3 and OV2008 prior to treatment with CEN09-106 and EDC1 was in the range of 500-1000 pA. Upon treatment with CEN09-106 and EDC1 (2.5 nM, each), the current in these two cell lines decreased to only 200-400 pA, a 60-75% decrease. In vivo administration of EDC1 in nonhuman primates established its low general toxicity profile. In vivo studies in xenograft mouse models are currently under way and are showing promising results with significant inhibition of SKOV3 and OV2008 tumors when CEN09-106 and EDC1 were administered intraperitoneally. In ongoing work, we are screening additional platinum-sensitive and -resistant ovarian cancer lines for their responses to EDC1. These basic and translational studies will serve as the foundation to demonstrate the clinical value of EDC1 in the treatment of patients with ovarian tumors.

Citation Format: Yousef Alharbi, Arvinder Kapur, Jim Prudent, David Marshall, Mildred felder, Bikash Pattnaik, Manish Patankar. Antibody-conjugated cardiac glycosides: Potent agents for treatment of ovarian cancer. [abstract]. In: Proceedings of the AACR Conference: Addressing Critical Questions in Ovarian Cancer Research and Treatment; Oct 1-4, 2017; Pittsburgh, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(15_Suppl):Abstract nr B11.

Image-based fluid dynamics analysis of left ventricle outflow tract pressure gradient after deployment transcatheter mitral valve

The goal of this study was to develop an image-based model to computational investigate blood flow and pressure gradients resulting from left ventricular (LV) wall motion after the implantation of a mitral valve (MV) prosthesis. Two image-based 3D models were reconstructed from multi-slice computed tomography images obtained from patients undergoing transcatheter MV replacement. Navier-Stokes equations were then used to compute the fluid motion. Outflow tract obstruction of the models with MV prosthesis were identified by calculating the difference between LV systolic and aortic pressures. It was found that computed outflow track obstruction compared well with actual obstruction data obtained from two patients. Our study indicates computational modeling can be a valuable tool to investigate the optimal placement of prosthetic valves guided by individualized anatomical data.