Sandwich Principle Research Articles

A universal three-dimensional hydrogel electrode for electrochemical detection of SARS-CoV-2 nucleocapsid protein and hydrogen peroxide

Coronavirus disease 2019 (COVID-19) is a highly contagious illness caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), resulting in a global health crisis. The primary diagnostic method for COVID-19 is quantitative reverse transcription PCR, which is time-consuming and requires expensive instrumentation. Here, we developed an electrochemical biosensor for detecting SARS-CoV-2 biomarkers using a 3D porous polyacrylamide/polyaniline hydrogel (PPG) electrode prepared by UV photopolymerization and in situ polymerization. The electrochemical immunosensor for detecting SARS-CoV-2 N protein via the immune sandwich principle demonstrated a lower detection limit of 42 pg/mL and comparable specificity to a commercial enzyme-linked immunosorbent assay, which was additionally validated in pseudoviruses. The electrochemical sensor for hydrogen peroxide showed a low detection limit of 0.5 μM and excellent selectivity, which was further confirmed in cancer cells under oxidative stress. The biomarkers of SARS-CoV-2 were successfully detected due to the signal amplification capability provided by 3D porous electrodes and the high sensitivity of the antigen-antibody specific binding. This study introduces a novel three-dimensional electrode with great potential for the early detection of SARS-CoV-2.

Hemodiyaliz tedavisi alan hastalarda serum Isı Şok Proteini B7 (HSPB7) ve tetranektin düzeylerinin belirlenmesi

Purpose: Heart damage may develop over time in patients with chronic renal disease and undergoing hemodialysis (HD) treatment. Serum levels of Heat shock protein B7 (HSPB7) and tetranectin proteins change following damage to the heart muscle. This study aimed to determine HSPB7 and tetranectin levels in hemodialysis (HD) patients.
 Materials and Methods: The patients aged 30-60, healthy and HD patients participated in the study and two groups were formed (n = 60): Control group (n = 30) and Patient group (n = 30). Blood samples were taken from healthy subjects who applied to the hospital for check-up and from patients with kidney disease receiving HD treatment. Biochemical parameters were examined from the blood taken. HSPB7 and tetranectin levels from isolated serum samples were determined using measurement kits based on the solid phase sandwich (ELISA) principle.
 Results: There was no significant difference between the groups in gender, age, glucose and Fe values of the subjects (P

Quantitative Detection of Procalcitonin with High Sensitivity, Specificity and Speed Based on SERS Magnetic Immunoassay

AbstractProcalcitonin (PCT), as a disease biomarker, is of significant importance in the early diagnosis of sepsis. To this end, we developed a surface‐enhanced Raman scattering (SERS) magnetic immunoassay that utilizes the double‐antibody sandwich principle for the rapid and quantitative detection of PCT. The core‐shell nanoparticles which contain Raman reporters (Au@XP013@AgNPs) are paired with tracer antibodies and coupled with biotin‐coupled capture antibodies, thereby forming a sandwich structure. This structure is readily captured by streptavidin (SA) magnetic beads and can be enriched by an external magnetic field. Raman spectroscopy was utilized to carry out detection, with PCT concentration ranging from 0–20 ng/mL. The Raman signal displays an excellent linear correlation with PCT concentration, and the LOD is 0.012 ng/mL, implying remarkable sensitivity. Efficiency of separation can be significantly enhanced by utilizing an external magnetic field, leading to a detection time of approximately 15 minutes. Thus providing a new technological reference for the clinical detection of sepsis biomarkers.

Coupled Hydromechanical Modelling of a Vertical Hydraulic Sealing System Based on the Sandwich Principle

For the shaft sealing of a repository for radioactive waste, a Sandwich sealing system was developed by KIT-CMM consisting of bentonite-based sealing segments (DS) and sand mixture-based equipotential segments (ES). To demonstrate the functionality of the Sandwich sealing system, various laboratory tests (MiniSandwich tests and semi-technical scale experiments) have been carried out before a large-scale experiment has been implemented in situ at the Mont Terri Rock Laboratory (CH). An important coupled process in the Sandwich system is the swelling deformation of the DS while aqueous fluid penetrates into the system. Consequently, the interparticle porosity (effective porosity) of the DS decreases by swelling strain, resulting in a reduction in the permeability of the DS. Pore space of the ES also decreases slightly due to swelling stress in the adjacent DS, which also leads to a reduction in the permeability of the ES. To understand the coupled hydromechanical processes of the Sandwich sealing system, a numerical model was developed to interpret the experimental observations from the MiniSandwich tests and to parameterize different components. A linear swelling model for DS and empirical functions for the swelling deformation-induced permeability change for both DS and ES segments were introduced into the coupled model with Richards’ flow and elastic model. Sensitivity analysis with parameter variations of the most important parameters reduces the uncertainty in the system behavior.

Development of a colloidal gold immunochromatographic strip with enhanced signal for the detection of bovine parvovirus.

Bovine parvovirus (BPV) is a pathogen responsible for respiratory and digestive tract symptoms in calves and abortion and stillbirth in pregnant cows. In this study, we developed a colloidal gold immunochromatographic (GICG) strip with an enhanced signal for detecting BPV according to the double-antibody sandwich principle and an enzyme-based signal amplification system to amplify the signal. This system utilizes horseradish peroxidase reacting with a substrate solution containing 3,3',5,5'-tetramethylbenzidine and dextran sulfate to obtain insoluble blue products on the test and control lines. We optimized different reaction conditions, including the amount of monoclonal antibodies (mAbs), pH of the colloidal gold solution, coating solution, blocking solution, sample pad treatment solution, antibody concentration in the control line, and antibody concentration in the detection line. The sensitivity of the signal-enhanced GICG strip showed that the minimum amount for detecting BPV was 102 TCID50, 10 times higher than that of the traditional GICG strip. The results of the specificity test showed that the signal-enhanced GICG strip had no cross-reactivity with BRV, BVDV, or BRSV. The results of the repeatability test showed that the coefficient of variation between and within batches was less than 5%, showing good repeatability. Moreover, for validation, PCR and the signal-enhanced GICG strip were used to detect 280 clinical bovine fecal samples. The concordance rate compared with PCR was 99.29%. Hence, the developed strip exhibited high sensitivity and specificity for the detection of BPV. Therefore, this strip could be a rapid, convenient, and effective method for the diagnosis of BPV infection in the field.

Lightweight panels with high delamination resistance made of integrally woven truss-like fabric structures

Lightweight panels are of high relevance for various applications, such as automotive, aerospace, civil engineering, and achieve high stiffnesses and strengths at low self-weight. The sandwich principle is commonly used to manufacture the panels, although conventional materials and reinforcement structures often limit the design and application of the panels in a wide range of possible applications. The reason for this is that lightweight panels fail either under combined compressive/shear loading or as a result of delamination of the individual layers. In this article, novel fabric structures are presented as a basis for the fabrication of lightweight panels that effectively overcome these deficiencies. These fabrics have a spatial truss-like structure, with the core and top layer being connected by continuously running reinforcing fibers. This results in high panel stability and high delamination resistance, which are evaluated in this article using mechanical tests in compression, flexure and combined tension-shear. The results are related to sample panels with conventional honeycomb core as reference. The high potential and excellent delamination resistance of the new fabric-based lightweight panels is shown in the result of the tests.

Associations of adiposity and adipokine concentrations with anti- and oxidative markers in Brazilian children

ObjectiveThe aim of this study was to evaluate the association of body fat, anti- and inflammatory adipokines with anti- and oxidative markers. MethodsWe conducted a cross-sectional study with 378 schoolchildren ages 8 to 9 y in Viçosa, Minas Gerais, Brazil. We obtained information on sociodemographic and lifestyle characteristics via questionnaires, measured height and weight, and estimated body fat by dual energy x-ray absorptiometry. Blood sample was collected to analyze the adipokines (adiponectin, leptin, chemerin, and retinol-binding protein 4) by enzyme-linked immunosorbent assay based on the sandwich principle; and anti- and oxidant markers (plasma ferric reducing antioxidant power [FRAP], superoxide dismutase [SOD], and malondialdehyde [MDA]) by enzymatic methods. Concentrations of anti- and oxidant markers were compared by percent body fat quartiles and adipokine concentrations terciles using of linear regression adjusted for potential confounders. ResultsTotal and central body fat were positively associated with FRAP. Every 1 standard deviation (SD) of total fat was associated with 4.8 higher FRAP (95% confidence interval [CI], 2.7–7). Additionally, every 1 SD of truncal, android, and gynoid fat were associated with, respectively, 5, 4.6, and 4.6 higher FRAP (95% CI, 2.9–7.1; 2.6–6.7; and 2.4–6.8, respectively). However, adiponectin was inversely associated with FRAP; every adiponectin SD was related to –2.2 lower FRAP (95% CI, –3.9 to –0.5). Chemerin was positively associated with SOD [5.4 (95% CI, 1.9–8.8) SOD units per chemerin SD]. ConclusionsThe body fat measures and adiposity-related inflammation (chemerin) were positively associated with antioxidative markers in children, whereas the adiponectin (anti-inflammatory marker) was inversely associated with FRAP (antioxidative marker).

Assessment of Monocyte Chemo-Attractant Protein-1 (MCP-1) and Other Biochemical Parameters in Iraqi Pregnant Women

The monocyte chemo-attractant protein-1 (MCP-1) is one of the pro-inflammatory cytokines. It controls the passage and infiltration of monocytes, macrophages, natural killers, and T cells into the sites of inflammation. The aim of this study is to inspect the role of MCP-1 in maternal metabolic, physiological changes and pregnancy complications like gestational diabetes mellitus, dyslipidemia, and hypertension to develop pharmaceutical strategies for these complications. This study included ninety Iraqi women divided into three groups: thirty pregnant women in their first trimester as the P1 group; thirty pregnant women in their third trimester as the P2 group; and thirty healthy non-pregnant women as the control or C group. Serum concentrations of MCP-1 were analyzed by the ELISA technique (sandwich principle). Fasting plasma glucose (FPG), C-reactive protein (CRP), fasting serum insulin (FSI), glycosylated hemoglobin (HbA1c), lipid profile, systolic, diastolic blood pressure, liver function enzymes ALT, AST and anthropometric parameters were measured. Our results revealed that serum MCP-1 significantly declined in the first trimester (P1) compared to the C group (p<0.05) and non-significantly declined in the third trimester (P2) compared to that in the C group, while there was a significant difference in serum MCP-1 between the P1 and P2 groups (p<0.05 ). Serum CRP showed a highly significant increase in the P1 and P2 groups compared to the C group at (p<0.01). There is a highly significant difference between the P1 and P2 groups (p<0.01). Serum MCP-1 had a significant positive correlation with body mass index (BMI), body fat percentage (BF %), systolic blood pressure (SBP) and C-reactive protein (CRP) in the P2 group (p<0.05). No significant differences in FPG or HbA1C were found between all the studied groups. Lipid parameters: TC, TG, LDL, and VLDL showed a highly significant increase in the P2 group compared to the C and P1 groups (p<0.01). HDL showed a highly significant decrease in the P2 group compared to the C group (p<0.01), while it was only significantly decreased in the P2 group compared to the P1 group (p<0.05). Depending on these results, we found that serum MCP-1 declines in pregnancy, the BMI, BF%, and the contractile arterial blood pressure (SBP) have a positive correlation with MCP-1 in late pregnancy, and the inflammation marker (CRP) has an independent association with MCP-1 in early gestation.

Highly sensitive SERS detection of IL-6 in serum by Au@Fe3O4 nanoring-based sandwich immunoassay

Detection of tumor markers is a key to realize the early diagnosis of cancer patients and improve the survival rate of patients. However, there are still great challenges in developing a highly sensitive and selective method to detect the tumor marker interleukin-6 (IL-6) of primary liver cancer, because the concentration of IL-6 in biological samples is limited and various interfering substances exist. Herein, a magnetic SERS immunoassay based on Fe3O4 nanoring (R-Fe3O4) was developed. The method could realize quantitative detection in 0.1–1000 pg/mL according to the sandwich principle and the detection limit of IL-6 reached 0.028 pg/mL. The excellent detection capability was mainly attributed to the characteristics of R-Fe3O4. Strong magnetism of R-Fe3O4 can enrich target molecules at low concentration, and the ring structure can facilitate the deposition of precious metal particles due to the high specific surface area, so as to promote the generation of hot spots and form electromagnetic enhancement. The method exhibited high selectivity for the identification of IL-6 and showed favorable detection results for IL-6 in serum samples. The ultra-sensitivity and high selectivity of the magnetic SERS immunoassay based on R-Fe3O4 would exhibit great development prospects in medical detection.

Ultra-efficient multiple cross displacement amplification-lateral flow biosensor (MCDA-LFB) for serogroup identification of prevalent Neisseria meningitidis

Meningococcal disease caused by Neisseria meningitidis remains a major global public health concern. Serogroup A, B, C and W135 were the major disease-causing serogroups. It is vital to timely and efficiently detect and differentiate these four serogroups. Herein, we developed multiple cross displacement amplification-lateral flow biosensor (MCDA-LFB) assays targeting ctrA, sacB, siaD, siaD and synG gene respectively for detection and subtyping of four N. meningitidis serogroups. This assay utilizes LFB to detect FITC and biotin-labeled target amplicons produced by MCDA through double antibody sandwich principle, to allow sensitive and specific detection under a constant temperature. The detection limit was as low as 10 fg or 100 fg genomic DNA in pure cultures and 5.5 CFUs or 36 CFUs in spiked cerebrospinal fluid (CSF) specimens, which were overall 100 to 1000-fold more sensitive than conventional PCR. High specificity of these assays was also validated through type strains and clinical isolates, with no cross-reactions. MCDA-LFB testing procedure can be finished within 1 h. In conclusion, the N. meningitidis- and serogroup-MCDA-LFB assays established in this study are simple, rapid and efficient, providing valuable molecular methods for diagnosis and surveillance of meningococcal disease, especially in resource-limited regions and when specimen culture fails.

Facilitating Student Voice through Sandwich Principle of Teaching (SPoT): Research-Led Teaching in English Language Teaching (ELT)

This study explores the implementation of the Sandwich Principle of Teaching (SPoT) in facilitating the students to voice their thoughts properly while learning about research in English Language Teaching (ELT). This case study is guided by the theory of research-led teaching from Walkington and SPoT from Wahl. The study employed 30 students of higher education as research participants. In 14 weeks, the teacher alternately used traditional and collaborative learning. The students were involved in various learning experiences; formulating lesson goals, reading journal articles, selecting the article, identifying the gap, and choosing and defining research topics. The findings revealed that the integration of SPoT into research-led teaching provides guidance for the teacher to teach research and space to voice their thought under the language learning research program. The findings show a positive attitude on students’ experiences in each stage of the learning research program through SPoT. Based on the findings, it is concluded that the integration of SPoT into research-led teaching could provide the students a space to voice their thought in the language learning research program. They got better learning experiences as they could engage actively in the class and voice their thoughts as well.

Association of Plasma Zinc and Prostate-Specific Antigen in Patients with Prostatic Cancer in Khartoum

Background: Prostate cancer is the most common visceral cancer in males, ranking as the second most common cause of cancer-related deaths in men older than 50 years of age, after carcinoma of the lung. It is predominantly a disease of older males, with a peak incidence between the ages of 65 and 75 years. This study aimed to estimate the plasma zinc level and plasma prostate-specific antigen (PSA) level in patients suffer from prostate cancer. Materials and Methods: A case–control study was conducted in Khartoum on 100 males aged more than 50 years old which were divided into 50 apparently healthy as control and 50 with prostate cancer as case. A 5 ml of blood specimens was collected in lithium heparin anticoagulants for the estimation of plasma zinc level using Buck model 210 VGP Atomic Absorption Spectrophotometer (East Norwalk, CT 06855) made in the USA and the plasma total PSA that was measured by immunoassay Sandwich principle HITACHI ROCHE COBAS E 411 (serial number 04641655190 V 13.0). Results: The mean level of plasma zinc was 0.35 mg/L ± standard deviation [SD] 0.14 in case and in control was 0.68mg/L ± SD 0.13, so the P value was 0.002 and PSA was 43.08 ng/ml ± SD 20.08 in case and 3.53 ng/ml ± SD 3.90 in control, so the P value was 0.000, the correlation between the level of plasma PSA with plasma zinc in patients with prostate cancer give R was 0.01 and R 2 was 0.001. Conclusion: This study concluded that PSA is significantly increased in patients with prostate cancer and plasma zinc level is significantly decreased in patients with prostate cancer. However, it is statistically significant.

Study of Eosinophil Count in Nasal and Peripheral Blood Smear Compare with Serum IgE Level in Children with Allergic Rhinitis

Introduction: Allergic rhinitis is one of the most common respiratory diseases. Patient with allergic rhinitis may have elevated level of serum IgE and eosinophil than normal person. Nasal smear eosinophil count is a simple test as well as noninvasive, can be repeated and inexpensive method for diagnosis of allergic rhinitis. Objective: To assess the eosinophil count in nasal smear as an alternative diagnostic test for children with allergic rhinitis. Methods: This cross-sectional study was conducted at the Department of Laboratory medicine and Paediatrics, BSMMU, Dhaka from September 2019 to August 2020 in 120 children (Age up to 18 years both sex). Diagnosed patients of allergic rhinitis according to ARIA-WHO guideline with history and clinical feature who fulfilled the inclusion criteria were selected as study population. After taking informed written consent blood and nasal secretion of allergic patient were drawn for serum IgE and eosinophil count. Nasal smears for eosinophil were stained using Giemsa stain and observed eosinophil under light microscope. Peripheral blood eosinophil count was estimated by hematology auto-analyzer (SYSMEX-XN 2000) and rechecked manually. The serum total IgE level was performed based on sandwich principle of ELISA. Results: The serum IgE level, nasal smear eosinophil count and blood eosinophil count were found increased with severity of allergic rhinitis, which was statistically significant (p<0.001). Pearson’s correlation coefficient test revealed significant positive correlation between nasal smear eosinophil count with serum IgE (r= +.656, p<0.001) and blood absolute eosinophil count (r= +.415, p<0.001). Conclusion: Nasal smear eosinophil count was significantly raised alone with absolute eosinophil count and serum IgE level with the severity of allergic rhinitis in children.

Transferring the sandwich principle to instructional videos: is it worth the effort?

BackgroundThe sandwich principle is an educational concept that regularly alternates between collective and individual learning phases within one learning unit. Applying sandwich principle to lectures has proven to be more effective for learning outcomes than classical lectures. Supposedly, this teaching format also leads to a beneficial knowledge transfer when applied to other teaching formats. Therefore, the aim of this study was to investigate the effect of the sandwich principle on instructional videos and how its use was evaluated by students.MethodsParticipants (n = 51) were randomly allocated into two groups. Both groups were given a test to assess the baseline level of knowledge. Afterwards, the control group watched the normal instructional video on cleft lips and palates, while the sandwich group watched the same video modified according to the sandwich principle. The participants then had to answer 30 single-choice questions to assess their knowledge gain and evaluate the instructional video. Long-term retention of the knowledge was tested again 6 months later using the same test questions. The unpaired t-test and ANOVA were used to compare the results.ResultsComparison of the pre-test and post-test results of both groups showed significantly increased test scores (p < 0.0001). Regarding long-term retention, the mean test scores were still significantly higher in both groups than before watching the video (p < 0.0001). For all test results, there was no significant difference between the groups (p > 0.05). The evaluation showed that the students highly appreciated the modified video and found the interruptions for repetition of previously learned knowledge useful.ConclusionThe hypothesis that the modification of instructional videos according to the sandwich principle would lead to an improved learning outcome could not be proved subjectively or objectively. Nevertheless, the teaching format was highly appreciated by the students and may have increased their motivation to learn with instructional videos.

Comparison of samples found positive by anti-HCV screening test with line immunoassay and determination of threshold value.

This study aimed to compare the serum samples found reactive (≥1-≤20 signal-to-cutoff ratio) with Elecsys antibodies to hepatitis C virus screening test with innogenetics-line immunassay hepatitis C Virus Score test and to determine the most appropriate threshold value for our country, since positive results close to the cutoff value cause serious problems in routine diagnostic laboratories. Antibodies to hepatitis C virus-positive samples from 687 different patients were included in the study. Antibodies to hepatitis C virus antibody detection was performed using Elecsys antibodies to hepatitis C virus II kits (Roche Diagnostics, Germany), an electrochemiluminescence method based on the double-antigen sandwich principle, on the Cobas e601 analyzer (Roche Diagnostics) in accordance with the recommendations of the manufacturer. Samples that were initially identified as reactive were studied again. Samples with ≥1-≤20 signal-to-cutoff ratio reagents as a result of retest were included in the study to be validated with the third-Generation Line immunassay kit (innogenetics-line immunassay hepatitis C Virus, Belgium). A total of 687 samples with antibodies to hepatitis C virus positive and levels between 1-20 S/Co were found to be 56.1% negative, 14.8% indeterminate, and 29.1% positive by innogenetics-line immunassay hepatitis C Virus confirmation test. When the cases with indeterminate innogenetics-line immunassay hepatitis C Virus test results were accepted as positive, the signal-to-cutoff ratio value for antibodies to hepatitis C virus was determined as 5.8 (95% confidence interval) in distinguishing the innogenetics-line immunassay hepatitis C Virus negative and positive groups. It was concluded that with further studies on this subject, each country should determine the most appropriate S/Co value for its population, and thus it would be beneficial to reduce the problems such as test repetition and cost increase.

TGF-β1 Gene Polymorphism and Its Correlation with Serum Level of TGF-β1 in Psoriasis Vulgaris Among Iraqi People.

PurposeMany cytokines have been implicated in the pathogenesis of psoriasis, among these the transforming growth factor-beta 1 (TGF-β1) can be endorsed by different mechanisms besides inhibiting keratinocytes proliferation. The role of genetic polymorphisms of TGF-β1 has been studied in various inflammatory diseases. Our aim is to study the correlation of TGF-β1 gene polymorphism at codon 10 and 25 with the expression of serum level of TGF-β1 in a sample of Iraqi psoriatic patients compared to the control group.Materials and MethodsA cross-sectional study involved 100 patients with psoriasis vulgaris and 50 sex- and age-matched healthy volunteers as control group. Serum and genomic DNA were prepared from peripheral blood samples. Amplification refractory mutation system–polymerase chain reaction technique (ARMS-PCR) had been applied for genotyping TGF-β1 codon 10 [rs1982073] and codon 25 [rs1800471] genetic polymorphisms. Enzyme-linked immunosorbent assay technique (ELISA) based on the sandwich principle was used for quantification of serum TGF-β1 level. Psoriasis Area and Severity Index (PASI) scoring was applied for determining the severity in psoriatic patients and classified accordingly to mild (PASI<7), moderate (PASI 7–12), severe (PASI>12) groups.ResultsStatistically significant difference was found in TGF-β1 gene polymorphism between psoriatic patients and control group at codon 10 (T869C) polymorphism (p=0.021) and codon 25 (G915C) polymorphism (p=0.040). No significant association was detected with the mean serum TGF-β1 level, severity of the disease, disease onset, gender, history of psoriatic arthritis, and smoking in both codons. Significant lower mean serum TGF-β1 level was found among psoriatic group (192.17 ± 531.12 ng/L) compared with controls (565.89 ± 1372.30 ng/L) (p = 0.018). Relation of mean serum TGF-β1 level with the onset of the disease was statistically significant (p = 0.004), early-onset disease group was lower (105.92 ± 68.02 ng/L) compared with the late-onset disease group (450.92 ±1027.79 ng/L). The mean serum TGF-β1 level showed no significant differences with the severity of psoriasis, gender, history of psoriatic arthritis, and smoking.ConclusionIraqi population showed a significant association between TGF-β1 gene polymorphism at codon 10 and 25 were with psoriasis susceptibility, and a significantly lower mean serum TGF-β1 level was detected in psoriatic patients.

The Sandwich principle: assessing the didactic effect in lectures on \u201ccleft lips and palates\u201d

BackgroundA teaching concept, that takes individual learning and personal belongings into account, is called the “sandwich principle.” This didactic method is an educational concept that alternates consecutively between individual and collective learning phases during a course. This study aimed to prove whether the application of the sandwich principle in lectures increases the learning outcome compared with classical lectures.MethodsAll participants (n = 64) were randomly allocated into two groups. One group attended a classical face-to-face lecture and the other attended a lecture that was modified according to the sandwich principle, including activating elements. To compare knowledge gain after the lectures, all the participants had to answer a test comprising40 single-choice questions. In addition, the lectures were evaluated.ResultsStudents attending the sandwich lecture had significantly better scores in the test than those who attending the classical lecture (p < 0.001). The mean test score of the sandwich group was 63.9% [standard deviation (SD) = 10] points and of the control group 50.2% (SD = 13.7 points). Overall, both the class conditions showed good evaluation results; however, students of the sandwich lecture were more satisfied with the lecture format compared with the other group.ConclusionOur study results confirm the thesis that the application of the sandwich principle in lectures increases the learning outcome compared with classical lectures. Even with a big audience, the sandwich design presents a concept that helps maintain high attention levels and addresses individual learning styles.

Procalcitonin (PCT) levels in pulmonary tuberculosis patients with acid fast bacilli positive and negative smear at Haji Adam Malik General Hospital, Medan, Indonesia

Background: Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis which enters the droplet nuclei into the mouth or nasal passages to reach the pulmonary alveoli. The sputum smear examination for smear-positive and negative smear pulmonary tuberculosis is challenging due to requiring a longer time to get the results. Therefore, a specific marker is needed that is able to detect bacterial infections immediately, such as procalcitonin (PCT). This study aims to determine the levels of PCT in pulmonary tuberculosis patients with acid-fast bacilli positive and negative smear at Haji Adam Malik General Hospital, Medan, Indonesia.Method: A cross sectional was conducted among 40 pulmonary tuberculosis patients who met the inclusion and exclusion criteria at Haji Adam Malik General Hospital, Medan, Indonesia. The subjects were 20 positive smears and 20 negative smears. PCT examination with mini VIDAS BRAHMS was carried out using the Sandwich principle using the ELFA method (Enzyme-Linked Fluorescent Assay). Sputum examination was carried out by smear of Zhiel Neelsen smear, which was analyzed by the Mann-Whitney (Non-Parametric) test using SPSS version 17 for Windows. Results: Most of the respondents were males in both positive and negative smears group (65.0% and 70.0%, respectively) and not significantly different (P&gt;0.05). The age of subjects was slightly older in positive smear (49.75 ± 17.993 years) compare with negative smear group (42.50 ± 14.816 years) but not statistically significant (P=0.172). The PCT levels in pulmonary tuberculosis patients with positive smear (0.1550; 21.65 ng/mL) differ significantly from the PCT levels in pulmonary tuberculosis patients with negative smear (0.05; 3.14 ng/mL) (p=0.0001). The cut off value using ROC found 0.06 ng/mL (AUC: 0.842) with a sensitivity of 80% and a specificity of 80%.Conclusion: There was a significant difference in the level of procalcitonin in patients with pulmonary tuberculosis who smear-positive and smear-negative.

Determination of the Reference Values of the Tumor Marker HE4 in Female Population of Canton Sarajevo.

Introduction:Ovarian cancer has the highest mortality rate of all gynecological tumors and represent fifth leading cause of cancer death in women, due to the absence of early symptoms of the disease and the lack of screening tests. A new HE4 ovarian cancer biomarker was found in various studies, with different populations having quite different sensitivity and specificity values as well as reference values. The tumor marker HE4 is a useful marker for ovarian cancer detection with only minimal expression in normal ovarian tissue. HE4 is particularly promising as a marker for early detection, showing its potential in differentiating women with ovarian cancer than those with benign (nonmalignant) ovarian conditions.Material and methods:Samples were taken in serum gel tubes, centrifuged and stored until analysis. A total of 300 respondents was included, of whom 188 were premenopausal women and 112 postmenopausal women. Respondents were divided into two groups by age: women aged 50-75 years and Control group of women aged 20-50 years. The HE4 assay was performed by the Immunological Test (ECLIA) for the quantitative determination of HE4 in human serum or plasma. Solid phase test, two-step reaction using immune 2HP and 3HD8 monoclonal antibodies („sandwich principle“).Results:Tumor markers HE4 analysis by groups indicate that in the postmenopausal group there was 92 (82.14%) of subjects with normal tumor markers HE4 and 170 (90.43%) in the premenopausal group. The elevated values of HE4 tumor markers in the postmenopausal group were in 20 (17.86%) cases and in the premenopausal group 18 (9.57%). Statistical analysis (nonparametric method) established the upper limit of the reference value of HE4 tumor markers in premenopausal and postmenopausal women.Conclusion:The established reference value for the women population in Canton Sarajevo for premenopausal women is <78.6 pmol/l, and for postmenopausal women <122.5 pmol/l. We found that the values of HE4 tumor markers differ significantly in premenopausal and postmenopausal women (p=0.0391). Postmenopausal women have a higher incidence of high-value tumor markers HE4. By comparison of the reference interval of the tumor marker HE4 for the population of women from Canton Sarajevo, determined by our research, with a reference interval for the German and Asian populations, we found a significant difference between the upper limit of the reference value in postmenopausal women (p<0.05), while in premenopausal women the difference was not statistically significant (p=0.4314).

To study the prevalence of insulin resistance in non-diabetes hypertensive subjects

Background: Hypertension is an important medical and public health problem in both developed and developing countries. It is an important risk factor for morbidity and mortality from coronary heart disease, stroke and renal disease. It is well recognized that hypertension coexists in varying degrees with conditions of obesity, insulin resistance/hyperinsulinemia and dyslipidemia, the interrelated metabolic disorders characteristic of metabolic syndrome.Methods: The study was carried out at Sri Guru Ram Das hospital, Amritsar, Punjab, India. A total of 150 patients were taken, out of which 75 were hypertensive and 75 healthy subjects more than 18 years of age were recruited. Serum insulin concentration was measured using a solid phase enzyme linked immunoassay based on the sandwich principle. Insulin resistance was determined by HOMA-IR (homeostasis model assessment of insulin resistance).Results: Statistically, the mean fasting serum insulin level was 17.09±8.17 μIu/ml in cases and 9.33±2.67μIU/ml in controls (reference range 2-25 μIU/ml); the difference was statistically significant (P &lt;0.001). The mean value of HOMA-IR in cases was 3.86±1.84 as compared with controls with mean HOMA -IR value of 2.01±0.62. This difference was statistically significant (P &lt;0.001).Conclusions: Essential hypertension is significantly associated with higher mean fasting insulin levels and insulin resistance. Hyperinsulinemia has a possible role in the pathophysiology of essential hypertension with insulin resistance being the likely predominant mechanism.