On viscoelastic drop impact onto thin films: axisymmetric simulations and experimental analysis

This study investigates the effect of fluid elasticity on axisymmetric droplets colliding with pre-existing liquid films, using both numerical and experimental approaches. The numerical simulations involve solving the incompressible flow momentum equations with viscoelastic constitutive laws using the finite volume method and the volume of fluid (VOF) technique to track the liquid's free surface. Here, the Oldroyd-B model is used as the constitutive equation for the viscoelastic phase. Experiments are also performed for dilute viscoelastic solutions with 0.005% and 0.01% (w/w) polyacrylamide in 80:20 glycerin/water solutions, in order to ensure the validity of the numerical solution and to investigate the elasticity effect. The formation and temporal evolution of the crown parameters are quantified by considering the flow parameters, including the fluid's elasticity. The results indicate that the axisymmetric numerical solutions reasonably agree with the experimental observations. Generally, the fluid's elasticity can enlarge the crown dimension at different thicknesses of the fluid film. Moreover, at intermediate values of the Weissenberg number, the extensional force in the crown wall can control the crown propagation. Furthermore, the results reveal that the effects of the Weber number and the viscosity ratio on this problem are more significant at higher values of the Weissenberg number.

The occurrence of flexion-relaxation phenomenon in elite cyclists during trunk forward bending

Flexion-relaxation phenomenon (FRP) is a well-known phenomenon in spinal extensor muscles. According to the literature, prolonged flexed posture leads to creep phenomenon and affects the active and passive neuromuscular control of the spinal column. The purpose of this study was to investigate FRP occurrence in elite cyclists that prolonged flexion posture is an integral part of their professional life. Their muscles' contraction pattern during forward bending was also compared. Electromyography (EMG) was recorded during flexion and extension from standing position in thoracic erector spinae (TES), lumbar erector spinae (LES) and gluteus maximus (Gluteus max) in 15 healthy male elite cyclists. In addition, the kinematic data related to the trunk angles were simultaneously recorded by a motion analysis system. Two-way ANOVA was used to assess the effects of muscle group and direction of movement on maximum amplitude of EMG activity. Among 15 cyclists, FRP was detectable in 60%, 87% and 73% of the participants in TES, LES and Gluteus max, respectively, and happened between 74% and 82% of the trunk flexion. There was no statistically significant difference in onset and offset of muscles FRP. Despite prolong hyper kyphotic posture, FRP was identifiable in TES, LES and Gluteus max muscles of elite cyclists.

Anthracycline chemotherapy and its effects on left ventricular mechanics: insights into the PROACT PLUS study

Funding Acknowledgements

Type of funding sources: Public hospital(s). Main funding source(s): South Tees Research and Development Fund

Background

Anthracyclines continue to form the backbone of chemotherapy treatment for breast cancer and lymphoma. However, their use has been directly associated with dose-dependent cardiotoxicity. Most studies to date have focused on the effects of high dose anthracyclines on left ventricular (LV) systolic function with a particular interest in peak global longitudinal strain (GLS). Not much attention has been directed to the effects of lower dose anthracyclines and other strain parameters of LV systolic and diastolic function.

Purpose

In this prospective study, we performed a comprehensive 2-dimensional echocardiographic assessment on the effects of anthracyclines on both the LV systolic and diastolic strain measures. We focused on the changes in the LV end-systolic (ES) GLS, myocardial GLS (myoGLS), global radial strain (GRS), global circumferential strain (GCS), myocardial GCS (myoGCS), twist and torsion. Additionally, peak systolic (PS), ES, early-diastolic (ED), and late-diastolic (LD) strain-rates were measured.

Methods

Patients with a new diagnosis of breast cancer or lymphoma undergoing anthracycline chemotherapy (any dose) were recruited between October 2018 to March 2020. Echocardiograms were performed pre-chemotherapy (V1) and 1 month post treatment (V2). These were analysed offline using vendor-independent software (TomTec 2D CPA). The study was ethically approved by the Health Research Association (REC reference 18/EM/0177).

Results

A total number of 62 were recruited into the study of which 7 patients passed away during treatment and 5 failed to attend their follow-up appointment at V2. Of the remaining patients, 6 dropped their LV ejection fraction (EF) to < 53% at V2 (G1). In these patients, a significant reduction in the LV ES-GLS (-19.3% vs. -15.3%, p = 0.0041), myoGLS (-16.8% vs. -12.8%, p = 0.0014), LV longitudinal PS strain-rate (-1 1/s vs. 0.78 1/s, p = 0.0063), and LV longitudinal ED strain-rate (1.1 1/s vs. 0.67 1/s, p = 0.026) was seen from V1 to V2. There was no statistically significant change in the other systolic and diastolic strain parameters in this group of patients. In patients with a normal EF at V2 (G2), a reduction in the LV ES-GLS (-20.8% vs. -19.9%, p = 0.013) and myoGLS (-17.9% vs. -16.9%, p = 0.012) was also seen from V1 to V2. Additionally, a deterioration in the LV radial ED strain-rate (-1.37 1/s vs. -1.2 1/s, p = 0.009), LV longitudinal ED strain-rate (0.98 1/s vs. 0.85 1/s, p = 0.01), and LV circumferential ED strain rate (1.62 1/s vs. 1.33 1/s, p = 0.045) was observed.

Conclusion

In G1, a more extensive deterioration (>15%) in the LV ES-GLS, myoGLS, and longitudinal ED strain-rate was evident when compared to G2. The additional reduction in LV early diastolic strain-rate in both patient groups highlights the global insult that anthracyclines can pose on both LV systolic and diastolic function. However, whether these findings translate into future development of cardiotoxicity is not yet known.

Right ventricular mechanics in anthracycline chemotherapy: insights into the PROACT PLUS study

Funding Acknowledgements

Type of funding sources: Public hospital(s). Main funding source(s): South Tees Research and Development Fund

Background

Anthracyclines are highly effective chemotherapy agents used in the treatment of many breast and haematological malignancies. However, one of the well-recognised associated risks with their use includes cardiotoxicity which can lead to heart failure and poor prognosis. Most studies have focused on the effects of these agents on the left ventricular systolic function. Right ventricular (RV) mechanics in anthracycline chemotherapy have so far been neglected.

Purpose

The PROACT PLUS study is an observational, prospective, cohort study which assesses the effects of anthracyclines on the RV systolic and diastolic measures using 2 dimensional conventional echocardiography and speckle tracking imaging (STE).

Methods

From October 2018 to March 2020, patients with a new diagnosis of lymphoma or breast cancer undergoing anthracycline chemotherapy were recruited into the PROACT PLUS study. Echocardiography was performed pre-chemotherapy (V1) and 1 month post chemotherapy (V2). Using vendor-independent software (TomTec Imaging Systems, 2D Cardiac Performance Analysis, Unterschleisshiem, Germany), offline analysis of tricuspid annular plane systolic excursion (TAPSE), RV fractional area change (FAC), tricuspid annular systolic velocity (S’), RV global longitudinal strain (RV GLS), RV myocardial longitudinal strain (RV myoGLS), RV free wall strain (RV FWS), RV- and RV free wall peak systolic (PS) strain-rates, end-systolic (ES) strain-rates, early-diastolic (ED) strain-rates and late-diastolic (LD) strain-rates were measured. This study was ethically approved by the Health Research Association (REC reference 18/EM/0177).

Results

62 patients were recruited into this study. Of these, 7 passed away during treatment and 5 failed to attend their follow-up appointment at V2. Of the remaining patients, a significant deterioration in the RV GLS (-25.4% vs. -22.5%, p < 0.0001), RV myoGLS (-22.4% vs. -20.9%, p = 0.005), RV ED strain-rate (1.08 1/s vs. 0.9 1/s, p = 0.01) and RV free wall ED strain-rate (1.24 1/s vs. 1.07 1/s, p = 0.02) was seen between V1 and V2. No statistical significant change was observed in the conventional and other strain measures of RV function. A total number of 6 patients developed left ventricular systolic dysfunction at V2 with ≥ 10% drop in the LV ejection fraction (LVEF) to < 53%. In this group of patients, there was a statistical significant reduction in the RV FWS (-25.5% vs. -22.7%, p = 0.03) which was not evident in the group of patients with preserved LVEF.

Conclusion

These findings suggest that adverse effects of anthracyclines are not purely confined to the LV, and RV systolic and diastolic changes are evident during treatment with anthracyclines, emphasising the global effect of these agents. A comprehensive RV assessment needs to be taken into consideration during the assessment of cardiotoxicity in patients undergoing chemotherapy treatment.

Atrial mechanics in anthracycline chemotherapy: insights into a prospective study

Funding Acknowledgements

Type of funding sources: Public hospital(s). Main funding source(s): South Tees Research and Development Fund

Background

In cancer treatment, detection of anthracycline induced cardiotoxicity (AIC) has been dependent on serial cardiac imaging to identify a reduction in left ventricular ejection fraction (LVEF) and more recently LV global longitudinal strain (GLS). However, studies have failed to assess the adverse effects of these agents on other cardiac chambers such as the left (LA) and right atria (RA).

Purpose

The PROACT PLUS study is an observational, prospective, cohort study investigating the effects of anthracyclines on the left and right atrial mechanics using 2 dimensional speckle tracking echocardiography (STE). We hypothesize that anthracyclines can affect the heart as a whole rather than solely affecting the LV.

Methods

From October 2018 to March 2020, patients with a new diagnosis of lymphoma or breast cancer receiving anthracycline chemotherapy were recruited into this study. Echocardiography was performed pre-chemotherapy (V1) and 1 month post-chemotherapy (V2). LA and RA volumes, LA (4-chamber)- and RA GLS, reservoir strains (RS), conduit strains (CS), contractile strains (CoS), peak-systolic (PS) strain-rates, early-diastolic (ED) strain-rates, and late-diastolic (LD) strain-rates were measured offline using vendor-independent software. This study was ethically approved by the Health Research Association (REC reference 18/EM/0177).

Results

A total number of 62 patients were recruited into this study. Unfortunately, 7 patients passed away during their treatment and 5 failed to attend their follow-up appointment at V2. From V1 to V2, there was a significant deterioration in the LA CS (-18.1% vs. -14.5%, p = 0.02) and LA ED strain-rate (-1.24 1/s vs. -0.86 1/s, p = 0.001). There was no other statistical significant change in the LA volume or other strain parameters. Additionally, there was a statistically significant decline in RA GLS (34.9% vs. 30.8%, p = 0.029), RA RS (41.1% vs. 37.1%, p = 0.03), RA CS (-23.8 vs. -20.6, p = 0.05), and RA ED strain-rate (-1.17 vs. -0.99, p = 0.02) with no significant change in the RA volume and other measures of RA strain.

Conclusion

These findings support our hypothesis that anthracyclines exert their cardiotoxic effects on all cardiac chambers including the atria. Whether these changes lead to subsequent permanent structural abnormalities in the atria hence increasing the future risk of atrial arrhythmias, or whether these changes predate subsequent cardiac dysfunction and poor prognosis, remains unknown. Long-term follow up and assessment of atrial mechanics is crucial in better understanding of AIC to help guide the future monitoring and management of patients undergoing cancer treatment.

The effects of doxorubicin on left and right atrial mechanics in patients with lymphoma

Background

Despite the associated dose-dependent cardiotoxicity, anthracyclines continue to form the backbone of modern chemotherapy regimens. Speckle Tracking Echocardiography (STE) has been a popular method of quantifying cardiac function but most studies have focused on left ventricular function. Research into the effects of anthracyclines on left atrial (LA) and right atrial (RA) function continues to be neglected.

Purpose

To investigate the effects of doxorubicin, a commonly used anthracycline, on both the LA and RA systolic and diastolic strain and strain-rate parameters in two groups of patients with lymphoma: Group 1 (G1) with a conventional drop in ejection fraction (EF <53%), and Group 2 (G2) without.

Methods

We retrospectively studied 46 patients treated for lymphoma between 2015 and 2018; G1 (n=12) and G2 (n=34). Echocardiograms performed at baseline (T0), mid-chemotherapy (T1), and post-chemotherapy (T2), were analysed by using offline vendor-independent software (TomTec, 2D Cardiac Performance Analysis). Using 2D STE, LA and RA reservoir, conduit and contractile strains, systolic and diastolic strain-rates were measured. Multi-level longitudinal model was used for statistical analysis.This study was ethically approved by the Health Research Association (REC Reference 18/SS/0139).

Results

Median age was 64 years (IQR 51–74 years) in G1, and 65 years (IQR 57–73 years) in G2. In G1, there was no significant change in LA reservoir strain with time, however a significant decline with an average mean difference of −7.52 was seen between T0 to T2 (p=0.016) in G2. LA conduit strain did not significantly change in either group with incremental doses of doxorubicin. However, LA contraction strain was seen to significantly increase in G1 between T1 to T2 (p=0.045) with an average change of 7.23. LA peak systolic strain rate, and late diastolic strain rate did not show any significant change with time in both groups. Yet, a significant increase was seen in LA early diastolic strain rate between T0 to T2 (p=0.017) in G1 but not G2. No significant changes were seen in the RA strain parameters in both groups.

Conclusion

In patient with a reduction in LV function, a significant change was noted in the left atrial contraction strain and early diastolic strain rate with incremental doses of doxorubicin. These changes shows the close relationship between the LA and LV, and the importance of LA in providing a compensatory mechanism for a decline in LV function secondary to anthracycline cardiotoxicity.

Funding Acknowledgement

Type of funding source: None

P1383 The effects of doxorubicin on left and right ventricular strain in patients with lymphoma: insights from a retrospective study

Funding Acknowledgements

South Tees Research and Development Fund (UK)

Background

Anthracyclines are a cornerstone in the management of lymphoma. However, their use is associated with cardiotoxicity. Speckle tracking echocardiography (STE) has been established as a valid measure of quantifying cardiac function. However, most studies to this date have focused predominantly on left ventricular (LV) global longitudinal strain (GLS) with only a limited number assessing the right ventricle (RV) and other LV strain parameters.

Purpose

Using 2D STE, we assessed the effects of anthracyclines on LV and RV strain parameters, focusing on LV endocardial (GLS), LV myocardial GLS (myoGLS), LV radial strain (GRS), RV endocardial (RV GLS), myocardial GLS (RV myoGLS), and RV free wall strain (RVFWS).

Methods

We retrospectively collected data on patients treated for lymphoma between 2015-2018. Two groups (G) were defined: those with a conventional drop in LV ejection fraction (EF), (G1, n = 11) and those without (G2, n = 24). Echocardiograms were performed pre-chemotherapy (T0), mid-treatment (T1), and post-chemotherapy (T2) and were analysed offline using vendor-independent software (TomTec 2D CPA). LV and RV strain analysis was performed in both groups. This study was ethically approved by Health Research Association (REC Reference 18/SS/0139).

Results

Mean age was 61 ± 16 years (G1) and 65 ± 12 years (G2). 18% (G1) and 17% (G2) of patients had a history of IHD in each group. Mean cumulative dose of doxorubicin was 280 ± 31 mg/m2 (G1) and 280± 48mg/m2 (G2). In both groups, there was no significant change in LV or RV strain parameters from T0 to T1. In G1, between T1 and T2, patients exhibited a significant deterioration in LV GLS (-19.7 ± 2.6% vs.-15.6 ± 2.5% p < 0.0005), and LV myoGLS (-17.3 ± 2.2% vs. -14.1 ± 2.9% p = 0.02). There was also a measurable decline in RV strain parameters between T1 to T2 (RV GLS, -23.1 ± 4.7% vs. -18.8 ± 4.2% p = 0.028) and (RV myoGLS -21.5 ± 5.2% vs -17.3 ± 3.6% p = 0.013). When analysed from T0 to T2, the changes in RV strain were more marked; RV GLS (-25.2 ± 4.9% vs. -18.8 ± 4.2% p = 0.005), RV myoGLS (-22.4 ± 5.2% vs-17.3 ± 3.6% p = 0.005), and RVFWS (-28.8 ± 5.7% vs. -20.9 ± 6.7% p = 0.001). In G2, no change was observed in LV GLS (-20.4 ± 2.3% vs. -19.6 ± 2.8% p = 0.66), LV myoGLS (-18.8 ± 2.5% vs. -17.5 ± 3.1% p = 0.18), RV GLS (-24.2 ± 2.3% vs. -23.1 ± 2.7% p = 0.42), RV myoGLS (-22.4 ± 2.9% vs. -20.6 ± 2.8% p = 0.09), RVFWS (-26.7 ± 4.6% vs. -25.2 ± 3.6% p = 1.0). GRS did not significantly change in either G1 or G2 during treatment.

Conclusion

In patients with a reduction in LVEF, this analysis demonstrated a significant reduction in LV strain parameters secondary to anthracycline treatment. Novel strain parameters did not change in the normal EF group, or predate EF/GLS decline in those with reduced LVEF. Measurable RV dysfunction was noted in those with LV deterioration, highlighting the global cardiac insult of anthracycline treatment. Preventative and monitoring strategies in cardio-oncology should not overlook RV function.

Pulsatile flow of non-Newtonian blood fluid inside stenosed arteries: Investigating the effects of viscoelastic and elastic walls, arteriosclerosis, and polycythemia diseases

BACKGROUND AND OBJECTIVE

In this study, the interaction of pulsatile blood flow with the viscoelastic walls of the axisymmetric artery is numerically investigated for different severities of stenosis. The geometry of artery is modeled by an axisymmetric cylindrical tube with a symmetric stenosis in a two-dimensional case. The effects of stenosis severity on the axial velocity profile, pressure distribution, streamlines, wall shear stress, and wall radial displacement for the viscoelastic artery are also compared to the elastics artery. Furthermore, the effects of atherosclerosis and polycythemia diseases on the hemodynamics and the mechanical behavior of arterial walls are investigated.

METHODS

The pulsatile flow of non-Newtonian blood is simulated inside the viscoelastic artery using the COMSOL Multiphysics software (version 5) and by employing the fluid-structure interaction (FSI) method and the arbitrary Lagrangian-Eulerian (ALE) method. Moreover, finite element method (FEM) is used to solve the governing equations on the unstructured grids. For modeling the non-Newtonian blood fluid and the viscoelastic arterial wall, the modified Casson model, and generalized Maxwell model are used, respectively.

RESULTS

According to the results, with stenosis severity increasing from 25% to 75% at the time of maximum volumetric flow rate, the maximum value of axial velocity and its gradient increase 7.9 and 19.6 times, and the maximum wall shear stress of viscoelastic wall increases 24.2 times in the constriction zone. With the progression of the atherosclerosis disease (fivefold growth of arterial elastic modulus), the wall radial displacement of viscoelastic arterial walls decreases nearly 40%.

CONCLUSIONS

In this study, axial velocity profile, pressure distribution, streamlines, wall radial displacement, and wall shear stress were examined for different percentages of stenosis (25%, 50%, and 75%). The atherosclerosis disease was investigated by the fivefold growth of viscoelastic arterial elastic modulus and polycythemia disease was examined by the 21-fold increase in the yield stress of the blood fluid. Furthermore, the comparison of results between the elastic and viscoelastic arterial walls shows that the wall radial displacement for viscoelastic artery is lower than that for the elastic artery as much as 21.7% for the severe stenosis of 75%.

Leaf proteomics of drought-sensitive and -tolerant genotypes of fennel

Fennel is attracted attention as a useful resource as researching medicinal plant for drought tolerance. To elucidate the response mechanism in drought-sensitive and -tolerant genotypes of fennel leaf, a gel-free/label-free proteomic technique was used. Fifty-day-old plants were subjected to drought stress for 60days. The relative water and proline contents were decreased and increased in sensitive genotypes, respectively; however, they were not a big change in tolerant genotypes. Photosynthesis was decreased in the sensitive genotypes under drought; however, it was increased in the tolerant genotype. In both drought-sensitive and -tolerant genotypes, proteins related to protein metabolism and cell organization were predominately affected under drought stress. The abundance of phosphoribulokinase and phosphoglycerate kinase enzymes were decreased and increased in drought-sensitive and -tolerant genotypes, respectively; however, the abundance of RuBisCO and glyceraldehyde-3-phosphate dehydrogenase enzymes were increased and decreased in drought-sensitive and -tolerant genotypes, respectively. Under drought stress, the abundance of glycolysis-related proteins was decreased in sensitive genotypes; however, they were increased in tolerance genotypes. Commonly changed proteins with polyethylene glycol fractionation such as cobalamin-independent methionine synthase were decreased and increased in drought-sensitive and -tolerant genotypes, respectively. These results suggest that cobalamin-independent methionine synthetase is involved in the tolerance of drought-tolerant fennel leaf under drought stress.

Effect of Cilia Beat Frequency on Muco-ciliary Clearance

BACKGROUND

The airway surface liquid (ASL), which is a fluid layer coating the interior epithelial surface of the bronchi and bronchiolesis, plays an important defensive role against foreign particles and chemicals entering lungs.

OBJECTIVE

Numerical investigation has been employed to solve two-layer model consisting of mucus layer as a viscoelastic fluid and periciliary liquid layer as a Newtonian fluid to study the effects of cilia beat frequency (CBF) at various amounts of mucus properties on muco-ciliary transport problem.

METHODS

Hybrid finite difference-lattice Boltzmann-method (FB-LBM) has been used to solve the momentum equations and to simulate cilia forces, and also the PCL-mucus interface more accurately, immersed boundary method (IBM) has been employed. The main contribution of the current study is to use an Oldroyd-B model as the constitutive equation of mucus.

RESULTS

Our results show that increasing CBF and decreasing mucus viscosity ratio have great effects on mucus flow, but the effect of viscosity ratio is more significant. The results also illustrate that the relation between cilia beat frequency and mean mucus velocity is almost linear and it has similar behavior at different values of viscosity ratio.

CONCLUSION

Numerical investigation based on hybrid IB-FD-LBM has been used to study the effect of CBF at various mounts of mucus viscosity ratio on the muco-ciliary clearance. The results showed that the effect of viscosity ratio on the muco-ciliary transport process is more significant compared with CBF.

Study on outbreak of Neospora caninum-associated abortion in dairy cows in Tabriz (Northwest Iran) by serological, molecular and histopathologic methods

OBJECTIVE

To determine Neospora caninum (N. caninum) as a cause of bovine abortion in dairy cows by ELISA, PCR and Pathological methods in Tabriz, Northwest of Iran.

METHODS

For study of outbreak of neosporosis, blood samples were collected from 76 Holstein aborted dairy cows in Tabriz (Northwest Iran). Antibodies to N. caninum were assayed by using a commercially ELISA kit (IDEXX, USA). IgG against N. caninum were found in 14 (18.4%) cases. Aborted fetuses of these seropositive dams were proposed for histopathological and molecular investigations. Brains, spinal cords and placentas of the fetuses were fixed in 10% buffered formalin for histopathology. Also 5-10 g of brain tissue was sampled for DNA extraction. In 6 out of 14 (42.8%) fetuses, brain tissue was positive in PCR. All dams of these fetuses were serologically seropositive in ELISA test.

RESULTS

Histopathologically, the lesions consistent with N. caninum were observed in brains, spinal cords and placenta of all fetuses. Lesions in CNS included severe congestion, perivascular and perineuronal edema, status spongiosis, perivascular cuffing, focal gliosis, nourophagy and focal necrosis. There were some Neospora-like cysts in brain. In placentas, severe congestion, perivascular infiltration of mononuclear cells, vascular thrombosis, focal placentitis and necrotic foci in cotyledons were noticed.

CONCLUSIONS

The results of present study agreed the results of similar studies about serological, histopathological and molecular results of other studies about neosporosis and it seems to support the outbreak of N. caninum-associated abortion in dairy cows in Tabriz (Northwest Iran).

Network and Nakamura tridiagonal computational simulation of electrically-conducting biopolymer micro-morphic transport phenomena

Magnetic fields have been shown to achieve excellent fabrication control and manipulation of conductive bio-polymer characteristics. To simulate magnetohydrodynamic effects on non-Newtonian electro-conductive bio-polymers (ECBPs) we present herein a theoretical and numerical simulation of free convection magneto-micropolar biopolymer flow over a horizontal circular cylinder (an "enrobing" problem). Eringen's robust micropolar model (a special case of the more general micro-morphic or "microfluid" model) is implemented. The transformed partial differential conservation equations are solved numerically with a powerful and new code based on NSM (Network Simulation Method) i.e. PSPICE. An extensive range of Hartmann numbers, Grashof numbers, micropolar parameters and Prandtl numbers are considered. Excellent validation is also achieved with earlier non-magnetic studies. Furthermore the present PSPICE code is also benchmarked with an implicit tridiagonal solver based on Nakamura's method (BIONAK) again achieving close correlation. The study highlights the excellent potential of both numerical methods described in simulating nonlinear biopolymer micro-structural flows.

Hepatitis B virus surface protein mutations clustered mainly in CTL immune epitopes in chronic carriers: results of an Iranian nationwide study

Mutations within the coding region of hepatitis B surface antigen (HBsAg) have been found naturally in chronic carriers. To characterize the mutations of HBsAg from Iranian chronic carriers who were vaccine and/or medication naive. The surface genes from 360 patients were amplified and directly sequenced. The distribution of amino acid substitutions was classified according to different immune epitopes of the surface protein. All isolates belonged to genotype D. 222 (61.6%) of 360 patients contained at least one amino acid substitution. 404 (74.5%) of 542 amino acid changes occurred in different immune epitopes of HBsAg, of which 112 (27.7%) in 32 residues of B-cell epitopes (62 in the 'a' determinant); 111 (27.4%) in 32 residues of T helper; and 197 (48.7%) in 32 residues inside cytotoxic T lymphocyte (CTL) epitopes. One Th (186-197) and two CTL (28-51 and 206-215) epitopes were found to be hotspot motifs for the occurrence of 213 (52.7%) substitutions. 20 stop codons were identified in different epitopes. There was a significant association between amino acid substitutions and anti-HBe seropositivity; however, the correlation between such changes with viral load and ALT levels was not significant. In chronic hepatitis B virus(HBV) carriers, positive selection in particular outside the 'a' determinant appeared to exert influence on the surface proteins. These changes could be immune escape mutations naturally occurring due to the host immune surveillance especially at the T-cell level.

Identification of Hepatitis B Virus Surface Antigen (HBsAg) Genotypes and Variations in Chronic Carriers from Isfahan Province, Iran

BACKGROUND

Hepatitis B virus (HBV) gene and protein variations are frequently been seen in chronic patients. The aims of study were to determine the genotypes as well as the patterns of variations distribution in chronically-infected patients from the central part of Iran.

METHODS

The surface gene was amplified, sequenced and subsequently aligned using international and national Iranian database.

RESULTS

All strains belonged to genotype D, subgenotype D1 and subtype ayw2. Of all 62 mutations occurred at 39 nucleotide positions, 31 (50%) were missense (amino acid altering) and 31 (50%) were silent (no amino acid changing). At the amino acid level, 30 substitutions occurred, however, 3 were in positions 122 and 127, corresponded to subtypic determination. 22 (73%) out of 30 amino acid mutations occurred in different immune epitopes within surface protein, of which 12 (54.54%) in B cell epitopes in 10 residues; 5 (45.45%) in T helper epitopes in positions; 5 (22.73%) in inside CTL epitopes in 4 residues.

CONCLUSION

The distribution of amino acid mutations as well as the ratio between silent and missense nucleotide mutations showed a narrowly focused immune pressure had already been on the surface protein in these patients, led to the emergence of escape mutants in these patients.

Correlation of Hepatitis B surface antigen mutations with clinical status of the chronically infected patients from Kermanshah, West of Iran

AIM

Hepatitis B virus (HBV) genetic and protein variations have been found in chronic HBV infected patients who did not receive any treatment and active or passive immunizations. The aims of this study were to determine the genotypes as well as the patterns of variations distribution in chronically infected patients from the west part of Iran.

METHODS

Forty-six people with chronic HBV infection were enrolled in the study. The surface genes were amplified, sequenced and subsequently aligned using international and national Iranian database.

RESULTS

All strains belonged to genotype D, subgenotype D1 and subtype ayw2. Of all 116 "mutations" that occurred at 59 nucleotide positions, 49 (42.2 %) were missense (amino acid altering) and 67 (57.7%) were silent (no amino acid changing), respectively. At the amino acid level, 38 (79.1%) out of 48 amino acid mutations occurred in different immune epitopes within the surface proteins, of which 2 (5.2%) occurred in B cell; 12 (31.5%) in T helper and 24 (63.1%) inside CTL epitopes. There were significant associations between amino acid mutations (especially within immune epitopes) and anti-HBe positivity and increased ALT levels (P values: 0.014 and 0.04, respectively).

CONCLUSION

The distribution of amino acid mutations as well as the ratio between silent and missense nucleotide mutations showed that a narrowly focused immune pressure had already been on the surface protein T cell epitopes (94.9% of mutations), particularly CTL epitopes which led to the emergence of escape mutants in these patients.

Optimum dose of ketamine for prevention of postanesthetic shivering; a randomized double-blind placebo-controlled clinical trial

Our objective was to investigate the efficacy and the optimum dosage of ketamine for post anesthetic shivering prevention. One-hundred and twenty patients (ASA I-II) scheduled for elective orthopedic surgery were randomly allocated to receive ketamine in 3 groups ; groups A (0.125 mg/Kg), groups B (0.25 mg/Kg) and C (0.5 mg/Kg) along with those receiving 0.9% normal saline as the placebo group. Tympanic temperature was measured immediately after induction of anesthesia, 30 min after induction, before administration of the study drug and by the end of the surgery. The four groups did not differ significantly in their hemodynamic parameters and tympanic temperature. The frequency of shivering was significantly less in groups B (0.25 mg/Kg) and C (0.5 mg/Kg) than in groups A (0.125 mg/Kg) and D (placebo). In addition recovery, extubation time and hallucination was observed to be less in group B compared to group A. Prophylactic 0.25 and 0.5 mg/kg ketamine was found to be effective in preventing postanesthetic shivering with a better response observed with 0.25 mg/kg dosage.

Dexamethasone in preventing post-dural puncture headache: a randomized, double-blind, placebo-controlled trial

Spinal anesthesia is major complication is Post-Dural Puncture Headache (PDPH) which is an intense and debilitating event. We decided to assess if intravenous administration of dexamethasone can decrease the incidence and/or intensity of this kind of headache. For this purpose 178 patients, who were supposed to undergo lower extremity orthopedic surgery, were enrolled in the study . Before spinal anesthesia was initiated, the first group (DXM-group) received 2 mL intravenous (i.v) dexamethasone whereas the second group (PCB-group) received 2 mL i.v. normal saline. After termination of surgery, a 7 days follow-up started to observe the possible occurrence and intensity of PDPH. There was no statistically significant difference between DMX and PCB groups regarding the incidence of PDPH. However, the intensity of headache differed between the two groups being less severe if IV dexamethasone had been given prophylactically. Dexamethasone can be used to decrease the severity of PDPH in patients who receive spinal anesthesia.

Toxicity of Trigonella foenum graecum (Fenugreek) in bone marrow cell proliferation in rat

Fenugreek has a wide range of medical applications and its medicinal use has been clear in several studies, however, few studies are available on effects on haematopoietic stem cell of bone marrow. The goal of the present study was to investigate the effect of Fenugreek on fetal macroscopic diameters and microscopic bone marrow cell histological changes in its teratogenic dosages. Fenugreek decoction was dissolved in 1.5 milliliter distilled water and injected intraperitoneumly in three dosages of 0.8 g/kg, 1.6 g/kg, and 3.2 g/kg for three groups of Wistar female rats mated by Wistar male. For another group (as control group) only 1.5 milliliter distilled water was injected. Bone marrow tissue was prepared from rat fetus and was cut using a microtome and stained with hematoxylin and eosin. Sections were evaluated for changes using light microscope. LD(50) for the measurement of teratogenic dosage of fenugreek was 4.1 and 3.5 g/kg in female and male rat, respectively. There was a positive relation between the injected drug dosage and fetal mortality rate. Among all fetal diameters, ear to ear diameter was decreased in groups received Fenugreek decoction. The severity of stem cell histological changes caused by 3.2 g/kg drug injection was lower than distilled water injection and in evaluation of other cells, differences in the severity of histological changes across three groups with different drug dosages and control group was detected. Fenugreek in teratogenic dosages can decrease the severity of bone marrow cell proliferation and increase fetal mortality rate.