A new concept of two-stage multi-element resonant-/cyclo-converter for two-phase IM/SM motor

The paper deals with a new concept of power electronic two-phase system with two-stage DC/AC/AC converter and two-phase IM/PMSM motor. The proposed system consisting of two-stage converter comprises: input resonant boost converter with AC output, two-phase half-bridge cyclo-converter commutated by HF AC input voltage, and induction or synchronous motor. Such a system with AC interlink, as a whole unit, has better properties as a 3-phase reference VSI inverter: higher efficiency due to soft switching of both converter stages, higher switching frequency, smaller dimensions and weight with lesser number of power semiconductor switches and better price. In comparison with currently used conventional system configurations the proposed system features a good efficiency of electronic converters and also has a good torque overloading of two-phase AC induction or synchronous motors. Design of two-stage multi-element resonant converter and results of simulation experiments are presented in the paper

Blood Profile in Normal One Humped Dromedary (Camelus Dromedarius) Camels in Libya. Part 3: Effect of Sex Variation on Biochemical and Haematological Blood Profile

As little is known about the blood profile of camels in Libya, this article is the third of a 4-part series describing the biochemical and haematological blood profile in Libyan camels.  In part 1 of these manuscripts, the overall blood biochemical and haematological mean values of camels in Libya were determined, parts 2-4 evaluate the effects of breed, gender and age respectively on these values. Blood samples were collected from 24 male and 42 female apparently healthy camels and the levels of enzymes, metabolites, electrolytes and haematological indices were measured.The blood of the male camels showed higher values of aspartate aminotransferase (AST), Lactate dehydrogenase (LDH), Amylase (AMS), total proteins, globulin and Phosphorus (Ph), than the female camels which showed higher values of glucose, Albumin/Globulin (A/G) ratio, urea, Iron (Fe), Calcium (Ca), Packed Cell volume (PCV), Haemoglobin (Hb), erythrocyte osmotic fragility, Mean Corpuscular Volume (MCV), Mean Corpuscular Haemoglobin (MCH), neutrophil and monocyte numbers. This study shows significant sex differences between male and female Libyan camels in many haematological and biochemical analytes

Immunoselected STRO-3(+) mesenchymal precursor cells reduce inflammation and improve clinical outcomes in a large animal model of monoarthritis.

BACKGROUND: The purpose of this study was to investigate the therapeutic efficacy of intravenously administered immunoselected STRO-3 + mesenchymal precursor cells (MPCs) on clinical scores, joint pathology and cytokine production in an ovine model of monoarthritis. METHODS: Monoarthritis was established in 16 adult merino sheep by administration of bovine type II collagen into the left hock joint following initial sensitization to this antigen. After 24 h, sheep were administered either 150 million allogeneic ovine MPCs (n = 8) or saline (n = 8) intravenously (IV). Lameness, joint swelling and pain were monitored and blood samples for leukocytes and cytokine levels were collected at intervals following arthritis induction. Animals were necropsied 14 days after arthritis induction and gross and histopathological evaluations were undertaken on tissues from the arthritic (left) and contralateral (right) joints. RESULTS: MPC-treated sheep demonstrated significantly reduced clinical signs of lameness, joint pain and swelling compared with saline controls. They also showed decreased cartilage erosions, synovial stromal cell activation and angiogenesis. This was accompanied by decreased infiltration of the synovial tissues by CD4⁺ lymphocytes and CD14⁺ monocytes/macrophages. Over the 3 days following joint arthropathy induction, the numbers of neutrophils circulating in the blood and plasma concentrations of activin A were significantly reduced in animals administered MPCs. CONCLUSIONS: The results of this study have demonstrated the capacity of IV-administered MPCs to mitigate the clinical signs and some of the inflammatory mediators responsible for joint tissue destruction in a large animal model of monoarthritis.This project was funded by a sponsored research agreement between the University of Melbourne and Mesoblast Ltd. AA was supported by a Libyan Government postgraduate scholarship, and LD was recipient of an Australian Postgraduate Award Scholarship

Immunoselected STRO-3+ mesenchymal precursor cells reduce inflammation and improve clinical outcomes in a large animal model of monoarthritis

Abstract Background The purpose of this study was to investigate the therapeutic efficacy of intravenously administered immunoselected STRO-3 + mesenchymal precursor cells (MPCs) on clinical scores, joint pathology and cytokine production in an ovine model of monoarthritis. Methods Monoarthritis was established in 16 adult merino sheep by administration of bovine type II collagen into the left hock joint following initial sensitization to this antigen. After 24 h, sheep were administered either 150 million allogeneic ovine MPCs (n = 8) or saline (n = 8) intravenously (IV). Lameness, joint swelling and pain were monitored and blood samples for leukocytes and cytokine levels were collected at intervals following arthritis induction. Animals were necropsied 14 days after arthritis induction and gross and histopathological evaluations were undertaken on tissues from the arthritic (left) and contralateral (right) joints. Results MPC-treated sheep demonstrated significantly reduced clinical signs of lameness, joint pain and swelling compared with saline controls. They also showed decreased cartilage erosions, synovial stromal cell activation and angiogenesis. This was accompanied by decreased infiltration of the synovial tissues by CD4+ lymphocytes and CD14+ monocytes/macrophages. Over the 3 days following joint arthropathy induction, the numbers of neutrophils circulating in the blood and plasma concentrations of activin A were significantly reduced in animals administered MPCs. Conclusions The results of this study have demonstrated the capacity of IV-administered MPCs to mitigate the clinical signs and some of the inflammatory mediators responsible for joint tissue destruction in a large animal model of monoarthritis

Effects of selective β1-adrenoceptor blockade on cardiovascular and renal function and circulating cytokines in ovine hyperdynamic sepsis

INTRODUCTION: Activation of the sympathetic nervous system has beneficial cardiovascular effects in sepsis, but there is also evidence that sympatholytics have beneficial actions in sepsis. We therefore determined the effect of selective β(1)-adrenoceptor blockade on cardiac and renal function and cytokine release in ovine hyperdynamic sepsis. METHODS: Hyperdynamic sepsis was induced by infusion of live E. coli for 24 hours in nine conscious sheep instrumented with flow probes on the pulmonary and left renal artery. Cardiovascular and renal function and levels of plasma cytokines were determined in a control group and during selective β1-adrenoceptor blockade with atenolol (10 mg intravenous bolus then 0.125 mg/kg/h) from 8 to 24 hours of sepsis. RESULTS: Hyperdynamic sepsis was characterized by hypotension with increases in cardiac output (CO), heart rate (HR) and renal blood flow (RBF), and acute kidney injury. Atenolol caused sustained reductions in HR (P <0.001) and CO (P <0.001). Despite the lower CO the sepsis-induced fall in mean arterial pressure (MAP) was similar in both groups. The sepsis-induced increase in RBF, decrease in renal function and increase in arterial lactate were unaffected by atenolol. Sepsis increased plasma levels of tumour necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and IL-10. Atenolol caused a further increase in IL-10, but did not affect levels of TNF-α or IL-6. CONCLUSIONS: In sepsis, selective β(1)-adrenoceptor blockade reduced CO, but not MAP. During sepsis, atenolol did not alter the development of acute kidney injury or the levels of pro-inflammatory cytokines, but enhanced the release of IL-10. Atenolol appears safe in sepsis, has no deleterious cardiovascular or renal effects, and has an anti-inflammatory effect

The use of phage display antibodies in defining alloantigens of canine RBC

TypescriptThesis (MVSc) -- University of Melbourne, Dept. of Veterinary Science, 2009Includes bibliographical references (leaves 73-80

The therapeutic use of mesenchymal precursor cells in an ovine collagen induced arthritis model of rheumatoid arthritis

© 2013 Dr. Anwar AbdalmulaRheumatoid arthritis (RA) is an autoimmune disease that affects 1% of the population and causes joint destruction, deformity and substantial disability. The current treatment of the disease alleviates the clinical symptoms to some extent but does not affect a cure. Also, the patient’s response to current therapeutic options is highly variable and often incomplete, reflecting the complex involvement of multiple pathways in RA disease progression. Furthermore, continuing anti-inflammatory treatment may suppress immune responses essential in host defense. Thus, despite current therapies, novel therapeutic approaches to RA are required. Mesenchymal stem cells (MSC) are self renewable, multipotent, non-hematopoietic progenitor cells that have the capacity to differentiate into various lineages like adipocytes, osteocytes and chondrocytes. Additionally, they have immunomodulatory properties that are considered as a potential therapy for immune mediated diseases and for RA in particular. To examine the therapeutic effect of these cells, animal models that can mimic the human disease are required in order to investigate the immunomodulatory effects of these cells. Collagen induced arthritis (CIA) is the most studied and used RA model in animals, as it shares many pathological and immunological features of the human disease. Although CIA has been examined in a number of species including mice, rats and monkeys, it has not been fully investigated in a large animal model that might offer more advantages over the current rodent models and which may more closely resemble humans in joint size and degree of load bearing. The aims of this study were first to develop the CIA model of RA in sheep and confirm its reproducibility and capacity to provide efficient assessment of disease activity before investigating the efficacy of allogeneic ovine mesenchymal precursor cells (MPC) which had been immune-selected and culture-expanded to reduce arthritis in this model. MPC are a later developmental stage of MSC and because of their purification techniques through the isolation using stro1 and stro3 antibodies, they are more homogeneous population of cells than MSC. Two subcutaneous (s.c.) injection of bovine collagen type II (BCII) in freund’s adjuvants followed with intra-articular (i.a.) injection of the same protein in saline in the hock joints has resulted in establishment of CIA in sheep with arthropathy displaying much of the classical pathology associated with human RA. Further, it provided clinical, histopathological and immunopathological features that can be used in testing biological therapeutics for the treatment of RA, such as stem cells. Following induction of arthritis with collagen, clinical signs of lameness and swelling were evident in all sheep and gross thickening of the synovium surrounding the hock joint and erosion on the cartilage surface was evident at necropsy (2 week and 6 week time points). Leukocyte cell counts and levels of antibodies to BCII were increased in serum and synovial fluid (SF), and there was synovial hyperplasia, thickening of the intimal layer, inflammation and marked angiogenesis in the synovial tissue. There was a large influx of monocytes and both T and B lymphocytes to the synovial tissue, many of which appeared to be in active phases of their cell cycle. After CIA establishment in sheep, the therapeutic effects of allogeneic ovine MPC were investigated in the early stages of CIA by Intravenous (i.v.) administration of MPC one day after arthritis induction. The development of arthritis was followed for two weeks before the sheep were euthanized. Sheep in the MPC treated group showed significantly reduced clinical signs throughout the trial and also showed significant reductions in the pro-inflammatory markers, IL-6 and acute phase proteins (APP) in blood. Activin A levels in both blood and SF of the treated group were also significantly lower than in the control group. Conversely, blood levels of the anti-inflammatory cytokine IL-10 showed a large spike following the administration of MPC. MPC treatment also lowered the neutrophil response in blood following arthritis induction, and the influx of CD4+ cells and monocytes into synovial tissues. All of these effects were accompanied by a significant reduction in the severity of histopathology in the synovial membranes of the treated hock joints compared to the control ones. These results indicate that the immunomodulatory features of MPC have a dramatic effect on acute inflammatory processes involved in arthritis and could become a first line treatment for reducing inflammation and destruction in the joints of people suffering from severe RA. The second MPC study in this thesis was to investigate the effects of MPC on later stages of arthritis using three different MPC doses and with i.v. and i.a. routes of administration. MPC were administered two weeks after arthritis induction and the sheep were monitored for four weeks. In the control sheep, histopathological analysis of hock joints demonstrated that the left hock synovium was characterized by leukocyte infiltration, synovial hyperplasia, pro-inflammatory cytokine expression, and cartilage erosion. In comparison with saline treated controls, synovial tissue from arthritic sheep receiving a single i.v. injection of MPC showed reduced histopathology scores and reductions in the expression of the pro-inflammatory cytokines IL-6, TNF-α, and IL-17 and absence of IL-1β expression. This was accompanied by a significant reduction in infiltrating monocytes/macrophages and a slight increase in the levels of the anti-inflammatory cytokine IL-10. The i.a delivery of MPC did not appear to lessen the intensity of the arthritis. These results indicate that a single i.v. injection of MPCs in an ovine model of collagen-induced RA attenuates joint inflammation, involving inhibition of the Th17 T cell subset and monocyte-derived production of multiple pro-inflammatory cytokines. Together, these data suggest that MPCs may have great potential as a first line treatment for joint inflammation and RA disease progression

Hematological And Biochemical Blood Changes In Chronic Tendinitis Thoroughbred Race Horses

Tendon injury is the most important veterinary reason for wastage of thoroughbred racehorses. Clinical diagnosis of tendon injuries is confirmed by a combination of clinical, ultrasonographic or post mortem examination of the injured limb. In addition, measurement of hematological and biochemical blood parameters are an important tool that aid health assessment and decision-making in diagnosis, treatment and follow-up of the injured tendon. Therefore, the lack of information or misinterpretation of these parameters may affect the accuracy of disease diagnosis and then lead to poor treatment. The present study was conducted to evaluate the levels of some hematological and biochemical parameter in the blood of thoroughbred horses affected by chronic tendinitis and compared with normal horses. Blood samples were collected from 15 healthy thoroughbred horses (8 stallions and 7 mares) and 21 tendinitis thoroughbred horses (11 stallions and 10 mares); and the levels of 18 blood parameters were determined. The tendinitis horses had higher number of erythrocytes and thrombocytes, higher values of packed cell volume (PCV) and mean corpuscular volume (MCV); lower enzyme activity of creatine kinase (CK), lower values of lactic acid (LA), icteric index and mean corpuscular hemoglobin concentration (MCHC) and lower numbers of band neutrophils than the normal horses. The chronic tendinitis mares had higher number of thrombocytes and lower values of lactate dehydrogenase (LDH) enzyme activity, lactic acid, plasma proteins, MCHC and lower numbers of white blood cells (WBC) than the normal mares. The chronic tendinitis stallions had higher levels of lactic acid, plasma proteins, MCV, and higher numbers of erythrocytes and thrombocytes,; and lower values of icteric jaundice, MCHC, band neutrophils than the normal horses. No significant differences were reported when tendinitis mares were compared with tendinitis males. However, normal mares showed higher levels of plasma proteins than normal stallions. The results obtained by this study can be used as useful index to diagnose and treat chronic tendinitis in horses.</jats:p

Endothelial dysfunction in an ovine model of collagen-induced arthritis

Background: Rheumatoid arthritis (RA) induces systemic inflammation, producing a range of co-morbidities including cardiovascular disease. An early vascular change is endothelial dysfunction, characterized by reduced endothelium-dependent vasodilation. The aim of this study was to assess endothelial function in isolated coronary and digital arteries using an ovine model of collagen-induced RA. Methods: Sheep were culled following induction of arthritis, and their endothelial function was compared to that of normal sheep. Paired arterial segments were mounted in a wire myograph and dilated with endothelium-dependent vasodilators [bradykinin, serotonin, carbachol and adenosine diphosphate (ADP); linked to either Gi or Gq signalling pathways] and endothelium-independent dilators (adenosine and sodium nitroprusside) to construct cumulative concentration-response curves. Results: Coronary arteries from arthritic sheep exhibited a significantly greater EC50 value for bradykinin-induced relaxation compared to non-arthritic controls (2.9 × 10-8M for arthritic sheep vs. 8.6 × 10-9M for controls). Digital arteries from arthritic sheep also exhibited a significantly greater EC50 for relaxation to ADP and a significant decrease in the carbachol maximal response. Responses to sodium nitroprusside were unchanged in both coronary and digital arteries. Conclusion: Sheep with RA demonstrated attenuated arterial relaxation to endothelium-dependent vasodilators. This may provide a useful model of endothelial dysfunction in chronic inflammatory conditions. The dysfunction did not appear to be associated with one specific G-protein signalling pathway. © 2014 S. Karger AG, Basel.BACKGROUND: Rheumatoid arthritis (RA) induces systemic inflammation, producing a range of co-morbidities including cardiovascular disease. An early vascular change is endothelial dysfunction, characterized by reduced endothelium-dependent vasodilation. The aim of this study was to assess endothelial function in isolated coronary and digital arteries using an ovine model of collagen-induced RA. METHODS: Sheep were culled following induction of arthritis, and their endothelial function was compared to that of normal sheep. Paired arterial segments were mounted in a wire myograph and dilated with endothelium-dependent vasodilators [bradykinin, serotonin, carbachol and adenosine diphosphate (ADP); linked to either Gi or Gq signalling pathways] and endothelium-independent dilators (adenosine and sodium nitroprusside) to construct cumulative concentration-response curves. RESULTS: Coronary arteries from arthritic sheep exhibited a significantly greater EC50 value for bradykinin-induced relaxation compared to non-arthritic controls (2.9 × 10(-8) M for arthritic sheep vs. 8.6 × 10(-9) M for controls). Digital arteries from arthritic sheep also exhibited a significantly greater EC50 for relaxation to ADP and a significant decrease in the carbachol maximal response. Responses to sodium nitroprusside were unchanged in both coronary and digital arteries. CONCLUSION: Sheep with RA demonstrated attenuated arterial relaxation to endothelium-dependent vasodilators. This may provide a useful model of endothelial dysfunction in chronic inflammatory conditions. The dysfunction did not appear to be associated with one specific G-protein signalling pathway

Modelling of Power Converters Using Z-Transform

The paper introduces a novel method of analysis and modelling of power electronic converters. Z-transform, numerical series (sequences) are used for both steady and transient states investigation of converters. The new impulse switching functions are created which are used as exciting functions of one- and multidimensional state-space models. Theoretical waveforms are compared with simulation results