Commissioning and performance assessment of diodes and MOSFETs in in-vivo dosimetry for external beam radiation therapy.

The precision of radiation therapy treatment depends on several calibration and quality assurance processes. In-vivo dosimetry (IVD) is used in external beam radiotherapy to evaluate the delivered versus planned dose as a patient-specific quality assurance verification procedure. This study aimed at assessing the performance of diodes (EDP-103G and EDP-203G) and metal oxide semiconductor field-effect transistors (MOSFETs) and corresponding correction factors followed by IVD evaluation in different treatment configurations.

Correlation of PD-L1 expression with different clinico-pathological and immunohistochemical features of ovarian surface epithelial tumors.

Background: Primary carcinoma of the ovary (OCs) are responsible for a significant number of deaths related to cancer, and have the highest rate of death related to cancers of the female reproductive organs. Programmed cell death 1 (PD1) protein, acts as an immune checkpoint, and has an important role in the down-regulation of the immune system by preventing the activation of T-cells, which will weaken the autoimmunity and increases self-tolerance. This study aimed at the evaluation of the immunohistochemical (IHC) expression of PD-L1 in various primary surface ovarian epithelial tumours and to test its correlation with different clinicopathological parameters together with the expression of a panel of P53, ER and PR.

Impact of splenectomy on circulating microparticles in patients with sickle cell anemia.

Introduction: Circulating microparticles (MP) are being described as potential biomarkers for disease activity in a variety of conditions including sickle cell anemia (SCA). However, relatively little is known about the influence of spleen status on MP levels in patients with SCA.

Methods: Using a prospective study design we characterize circulating MP in 144 patients with SCA in steady state by assessing their cellular origin and their relationships to spleen status defined by clinical and imaging findings.

Coexistence of sickle cell disease and systemic lupus erythematosus is associated with quantitative and qualitative impairments in circulating regulatory B cells.

The incidence of connective tissue diseases such as systemic lupus erythematous (SLE), in adult patients with sickle cell disease (SCD), appears to be increasing. The exact causes underlying this increased risk are still unknown, but a link with B regulatory (Breg) cells is possible as these cells suppress inflammatory responses, and maintain tolerance. Quantitative and qualitative analyses of circulating Breg cells were performed in a cohort of SCD patients with SLE, and their levels were correlated with key soluble mediators promoting autoreactive B cells.

A Comparison of Two Scales to Determine Prevalence of Mood Disorders in Omani Patients Recently Diagnosed with Cancer.

Objectives: Studies on the prevalence rate of mood disorders in patients recently diagnosed with cancer from Middle East are scare in the literature. Therefore, this study assesses the prevalence rates of anxiety and depression, and their associations with socio-demographic factors, in recently diagnosed patients with cancer living in the Sultanate of Oman.

Methods: In this prospective study, adult patients were interviewed within the first three months of diagnosis of cancer using the Hospital Anxiety and Depression Scale (HADS), and the Centre for Epidemiological Studies Depression (CES-D) Scale.

A Surrogate Water Quality Index to assess groundwater using a unified DEA-OWA framework.

In this paper, we introduce a new approach, based on a unified framework incorporating Data Envelopment Analysis (DEA) and Ordered Weighted Averaging (OWA), for assessing water quality in contextual settings that involve a large number of hydrochemical parameters. In order to enhance discrimination among water sources, the DEA model is adopted with data-driven input variables, called "surrogate optimistic closeness values," computed through an aggregation procedure that includes the observed values of the hydrochemical parameters with OWA weights. The proposed DEA-OWA methodology has been employed to assess the quality of 51 water samples, collected from irrigation wells in Sereflikochisar Basin, Turkey, by means of 19 hydrochemical parameters.

Low-Level Viremia Predicts Virological Failure in HIV-Infected Omani Patients Receiving Antiretroviral Therapy.

Background: The implication and clinical significance of low-level viremia (LLV) in HIV patients are still not clear. This study aimed to characterize the clinical outcomes and to evaluate whether LLV could predict future virological failure in a well-defined cohort of HIV-infected Omani patients attending a large HIV clinic.

Methods: Patients on regular antiretroviral therapy (ART) for at least 12 months, and had at least 2 HIV RNA measurements 1 year after starting ART, were prospectively enrolled in a cohort study.

Respiratory Viral Infections in Sickle Cell Anemia: Special Emphasis on H1N1 Co-infection.

Objectives: Patients with sickle cell anemia (SCA) are immunocompromised and at an increased risk of developing infections. Our aim was to establish the clinical, laboratory, and radiological manifestations of respiratory viral infections in SCA at Sultan Qaboos University Hospital (SQUH), Oman and assess its impact on disease morbidity and mortality, with special emphasis on H1N1.

Methods: We undertook a retrospective study in SCA patients with respiratory viral infections following up at the hematology department at SQUH.

Students' Perceived Benefits of Integrating a BSc in Health Sciences within a Medical Degree at Sultan Qaboos University.

Objectives: After completing the pre-clinical phase of a Doctor of Medicine (MD) curriculum, undergraduate medical students may choose to add a Bachelor of Science (BSc) degree in health sciences to their MD degree. Limited data exists on the motives behind students' decisions to undertake such intercalated degrees. Hence, this study aimed to identify the factors that influence students in making this choice.

The Value of Programmed Death Ligand 1 Expression in Cancer Patients Treated with Neoadjuvant Chemotherapy.

Programmed death ligand 1 (PD-L1) is an inhibitory molecule expressed by cancer cells to supress T-cell activity and escape anti-tumour immunity. The role of PD-L1 in cancer has been studied extensively as it is considered an important immune checkpoint against immune over-activation through its interaction with Programmed death receptor 1 (PD-1) expressed on activated lymphocytes. PD-L1 expression was found to be enhanced by chemotherapy through different proliferation pathways.

Elevated levels of circulating invariant natural killer cell subsets are skewed toward Th2-like phenotype in children with sickle cell disease.

Invariant natural killer T (iNKT) cells are being considered as potential targets for immunotherapeutic strategies in a variety of conditions including sickle cell disease (SCD). However, relatively little is known about the fate of iNKT cell subsets in children with SCD. Herein, quantitative and qualitative analyses of circulating iNKT cell subsets were carried out in 120 children in steady state and 30 healthy controls.

Comparative Analysis of two Methods of Measuring Antiretroviral Therapy Adherence in HIV-Infected Omani Patients.

Background: Antiretroviral therapy (ART) adherence is crucial to achieve HIV suppression and to prolong survival of HIV-infected patients. Although monitoring of ART adherence is standard of HIV care, there is yet no optimal method to measure ART adherence. Therefore, it is essential to compare the effectiveness of different adherence measurement tools to predict HIV suppression.

Levels of regulatory T cells and invariant natural killer cells and their associations with regulatory B cells in patients with non-Hodgkin lymphoma.

Due to their immunoregulatory properties, several specialized cell subsets, including regulatory T (Treg), invariant natural killer T (iNKT) and regulatory B (Breg) cells, are involved in the pathogenesis of non-Hodgkin lymphoma (NHL). However, the interaction between various cells remains to be elucidated. The aim of the present study was to evaluate the levels of Treg, iNKT and Breg cell subsets and their interrelationships in the peripheral blood (PB) and bone marrow (BM) of patients with B-cell NHL who received rituximab-based regimens and achieved a complete remission.

Hemoglobin F as a predictor of health-related quality of life in children with sickle cell anemia.

Purpose: As treatment options for children with sickle cell anemia (SCA) continue to expand survival, evaluation of factors associated with health-related quality of life (HRQoL) is becoming an important aspect for further improving clinical management. Although the general features of SCA are similar, factors influencing HRQoL within a country may differ from those of other countries, therefore this study aimed to explore factors affecting HRQoL in children with SCA living in the Sultanate of Oman.

Methods: This was a cross-sectional study in which the PedsQL™ Sickle Cell Disease Module was used to evaluate the overall HRQoL in children with SCA.

Does sickle cell disease have a psychosomatic component? A particular focus on anxiety and depression.

Sickle cell disease, an early-age genetic condition, encompasses a range of blood disorders with severe complications. This disease is characterized by the synthesis of abnormal hemoglobin molecules, which tend to polymerize due to their low solubility upon deoxygenation in the peripheral capillary beds, resulting in sickle-like red blood cells. Sickled cells lose their normal functioning and hemodynamic properties, leading to chronic fatigue as well as to episodes of painful crises.

Regulatory B Cells Are Functionally Impaired in Patients Having Hemophilia A With Inhibitors.

Development of inhibitors remains a major clinical complication in patients with hemophilia A receiving replacement therapy with factor VIII (FVIII). Understanding the immune mechanisms involved in the development of inhibitors can provide valuable information about pathways to human tolerance. Recent evidence indicates that B regulatory (Breg) cells play a pivotal role in controlling the production of antibodies (Abs) while promoting follicular T helper (Tfh) cells and monocytes, expressing the low-density lipoprotein receptor-related protein (LRP/CD91), which is involved in FVIII intake from the circulation.

and Epstein-Barr Virus Co-Infection in a Patient with Hemophagocytosis.

The authors describe a rare case of a 27- year old previously healthy male presenting with high grade fever, pancytopenia, hepatosplenomegaly, high levels of ferritin and triglyceride, suggesting a diagnosis of hemophagocytic lymphohistiocytosis (HLH) syndrome. Other investigations showed a positive serology and high Epstein-Barr virus (EBV) viremia. The diagnosis of a visceral leishmaniasis was confirmed by bone morrow biopsy, which showed Leishman-Donovan bodies and evidence of HLH.

Accuracy of Platelet Counting by Optical and Impedance Methods in Patients with Thrombocytopaenia and Microcytosis.

Objectives: Obtaining accurate platelet counts in microcytic blood samples is challenging, even with the most reliable automated haematology analysers. The CELL-DYN(™) Sapphire (Abbott Laboratories, Chicago, Illinois, USA) analyser uses both optical density and electronic impedance methods for platelet counting. This study aimed to evaluate the accuracy of optical density and electrical impedance methods in determining true platelet counts in thrombocytopaenic samples with microcytosis as defined by low mean corpuscular volume (MCV) of red blood cells.

Programmed death-1 is a marker for abnormal distribution of naive/memory T cell subsets in HIV-1 infection.

Chronic activation of T cells is a hallmark of HIV-1 infection and plays an important role in disease progression. We previously showed that the engagement of the inhibitory receptor programmed death (PD)-1 on HIV-1-specific CD4(+) and CD8(+) T cells leads to their functional exhaustion in vitro. However, little is known about the impact of PD-1 expression on the turnover and maturation status of T cells during the course of the disease.

HLA-DO increases bacterial superantigen binding to human MHC molecules by inhibiting dissociation of class II-associated invariant chain peptides.

HLA-DO (H2-O in mice) is an intracellular non-classical MHC class II molecule (MHCII). It forms a stable complex with HLA-DM (H2-M in mice) and shapes the MHC class II-associated peptide repertoire. Here, we tested the impact of HLA-DO and H2-O on the binding of superantigens (SAgs), which has been shown previously to be sensitive to the structural nature of the class II-bound peptides.

Multiple cycles of rituximab therapy in chronic refractory immune thrombocytopenia: a case report with a 10-year follow-up.

Immune thrombocytopenia (ITP) is an autoimmune disease characterized by isolated low platelet counts often leading to mucocutaneous bleeding. Administration of rituximab was shown to increase platelet counts in patients relapsing chronic ITP. However, duration of response with rituximab and the long-term benefit remains unknown.

Immunotherapy for B-Cell Neoplasms using T Cells expressing Chimeric Antigen Receptors: From antigen choice to clinical implementation.

Immunotherapy with T cells expressing chimeric antigen receptors (CAR) is being evaluated as a potential treatment for B-cell neoplasms. In recent clinical trials it has shown promising results. As the number of potential candidate antigens expands, the choice of suitable target antigens becomes more challenging to design studies and to assess optimal efficacy of CAR.

Autologous HIV-1 clade-B Nef peptides elicit increased frequency, breadth and function of CD8+ T-cells compared to consensus peptides.

Objective: To determine the function and phenotype of CD8(+) T-cells targeting consensus and autologous sequences of entire HIV-1 Nef protein.

Methods: Multiparameter flow cytometry-based analysis was used to evaluate the responses of two treatment naïve HIV-infected individuals, during primary and the chronic phases of infection.

Results: A greater breadth and magnitude of CD8 IFN-γ responses to autologous compared to clade-B consensus peptides was observed in both subjects.

CD160 and PD-1 co-expression on HIV-specific CD8 T cells defines a subset with advanced dysfunction.

Chronic viral infections lead to persistent CD8 T cell activation and functional exhaustion. Expression of programmed cell death-1 (PD-1) has been associated to CD8 T cell dysfunction in HIV infection. Herein we report that another negative regulator of T cell activation, CD160, was also upregulated on HIV-specific CD8 T lymphocytes mostly during the chronic phase of infection.