A simple, rapid and objective infectivity assay based on an in situ enzyme immunoassay (EIA) was developed for the fast-growing and cytopathic cell culture-adapted hepatitis A virus (HAV) strain HM175A.2. Infectivity titration by EIA correlated well with titration by cytopathic effects. The reliability of this assay was demonstrated by close agreement in virus infectivity titers among different assays of the same virus aliquot and between assays of different virus aliquots. HAV infected cell cultures after fixation could be stored for up to 1 week before testing without decline in virus titer.
Apoptosis of host cells profoundly influences virus propagation and dissemination, events that are integral to influenza A virus (IAV) pathogenesis. The trigger for activation of apoptosis is regulated by an intricate interplay between cellular and viral proteins, with a strong bearing on IAV replication. Though the knowledge of viral proteins and mechanisms employed by IAV to induce apoptosis has advanced considerably of late, we know relatively little about the repertoire of host factors targeted by viral proteins. Thus, identification of cellular proteins that are hijacked by the virus will help us not only to understand the molecular underpinnings of IAV-induced apoptosis, but also to design future antiviral therapies. Here we show that the nucleoprotein (NP) of IAV directly interacts with and suppresses the expression of API5, a host antiapoptotic protein that antagonizes E2F1-dependent apoptosis. siRNA-mediated depletion of API5, in NP-overexpressed as well as IAV-infected cells, leads to upregulation of apoptotic protease activating factor 1 (APAF1), a downstream modulator of E2F1-mediated apoptosis, and cleavage of caspases 9 and 3, although a reciprocal pattern of these events was observed on ectopic overexpression of API5. In concordance with these observations, annexin V and 7AAD staining assays exhibit downregulation of early and late apoptosis in IAV-infected or NP-transfected cells on overexpression of API5. Most significantly, while overexpression of API5 decreases viral titers, cellular NP protein as well as mRNA levels in IAV-infected A549 cells, silencing of API5 expression causes a steep rise in the same parameters. From the data reported in this manuscript, we propose a proapoptotic role for NP in IAV pathogenesis, whereby it suppresses expression of antiapoptotic factor API5, thus potentiating the E2F1-dependent apoptotic pathway and ensuring viral replication.
Power electronics and fuel cell technologies play an important role in the field of renewable energy. The demand for fuel cells will increase as fuel cells become the main power source for portable applications. In this application, a high-efficiency converter is an essential requirement and a key parameter of the overall system. This is because the size, cost, efficiency, and reliability of the overall system for portable applications primarily depend on the converter. Therefore, the selection of an appropriate converter topology is an important and fundamental aspect of designing a fuel cell system for portable applications as the converter alone plays a major role in determining the overall performance of the system. This paper presents a review of power electronics applications in fuel cell systems, which include various topology combinations of DC converters and AC inverters and which are primarily used in fuel cell systems for portable or stand-alone applications. This paper also reviews the switching techniques used in power conditioning for fuel cell systems. Finally, this paper addresses the current problem encountered with DC converters and AC inverter.
Mesenchymal stem cells (MSC) are multipotent, self-renewing cells that can be found mainly in the bone marrow, and other post-natal organs and tissues. The ease of isolation and expansion, together with the immunomodulatory properties and their capability to migrate to sites of inflammation and tumours make them a suitable candidate for therapeutic use in the clinical settings. We review here the cellular mechanisms underlying the emerging applications of MSC in various fields.
Adult onset still's disease usually presents with high grade intermittent fever, polyarthritis, salmon pink evanescent rash and hepatosplenomegaly. Pulmonary involvement in the form of pneumonitis, as a presenting feature is very rare. We report a case of a young lady who presented with fever, cough and respiratory distress. Chest X-ray revealed patchy infiltration in left upper lung zone. She was subsequently diagnosed as Adult onset Still's disease. There was no improvement in clinical condition despite five days of antibiotics. On trans-bronchial lung biopsy (TBLB) proved she had interstitial pneumonitis and responded dramatically to steroid treatment.
Coeliac artery thrombosis with ischaemia is a rare condition, which usually presents with severe peptic ulcer disease symptoms. It is usually associated with risk factors for thrombosis or embolism. The manifestation is rare because of large number of collaterals between the coeliac and superior mesentery artery. Early detection and intervention is required to prevent the progression of its complications that includes gastric ischaemic necrosis.
Normal platelet functions are critical for achieving primary haemostasis. Numerous medications have been shown to affect platelet functions. Pyridostigmine (Mestinon), an orally active cholinesterase inhibitor that is commonly used to treat myasthenia gravis has been documented to cause epistaxis and prolonged bleeding after a cut in anectodal reports. This study was initiated after a patient diagnosed to have myasthenia gravis, developed multiple bruises a week after being started on Mestinon. The objective of this study was to investigate the effect of Mestinon on platelet aggregation stimulated with various agonists in vitro.
We report a rare case of recurrent infection of Chromobacterium violaceum in an immunocompromised patient. Despite the high mortality rate associated with this infection as reported in the literature, this patient survived three episodes of recurrent infection. We believe that with high clinical suspicion, prompt treatment and appropriate antimicrobial agents, it is possible for clinicians to treat this infection effectively and reduce the mortality rate.
Mesenchymal stem cells are pluripotent progenitors that could be found in human bone marrow. Mesenchymal stem cells are capable of renewing themselves without differentiation in long-term culture. These cells also have low immunogenicity and can suppress alloreactive T cell responses. In the current study, mesenchymal stem cells isolated and propagated previously from the bone marrow of a megaloblastic anaemia patient were tested for their capabilities to differentiate into adipocytes, chondrocytes and osteoblasts in vitro. The differentiated cells were determined by Oil Red O, Alcian Blue-PAS and Alizarin Red S staining, and reverse transcriptase-polymerase chain reaction to determine the expression of mRNA specific for adipogenesis, chondrogenesis and osteogenesis. The results showed that the fibroblast-like cells were capable of differentiating into adipocytes, chondrocytes and osteoblasts upon chemical induction. The adipocytes, chondrocytes and osteoblasts were stained positively to Oil Red O, Alcian Blue-PAS and Alizarin Red S respectively. The differentiated cells were also found to express mRNA specific for adipogenesis ('peroxisome proliferation-activated receptor gamma2' and lipoprotein lipase), chondrogenesis (collagen type II) and osteogenesis (osteocalcin, osteopontin and alkaline phosphatase). In conclusion, this research has successfully isolated fibroblast-like cells from human bone marrow and these cells demonstrated morphological, cytochemical and immunochemical characteristics similar to mesenchymal stem cells. These cells maintain their proliferative properties and could be differentiated into the mesoderm lineage. The success of this study is vital because mesenchymal stem cells can be used in cellular therapy to regenerate or replace damaged tissues, or as a vehicle for therapeutic gene delivery in the future.
Catheterization of the umbilical artery has been a useful aid in the management of sick neonates for the past few decades. However, it is associated with various complications. Reported studies strongly suggest a significant role of intravascular catheterization in the development of aortic thrombi. Increase in thrombosis of large vessels is believed to be related to mechanical injury in the catheterized vessels, which provide direct exposure of blood to tissue factor (TF), the primary cellular initiator of the extrinsic coagulation pathway. This study was conducted to determine the levels of plasma TF, tissue factor pathway inhibitor (TFPI) and D-dimer (DD) in infants with umbilical arterial catheter (UAC)-associated thrombosis. Quantification of TF was carried out using an in-house sandwich ELISA, whereas TFPI and DD levels were measured with commercial immunoassay kits. Infants with UAC inserted were found to have significantly higher levels of plasma TF (p < 0.001) than baseline levels. However, there were no significantly elevated levels of TFPI or DD. Infants with UAC-associated thrombosis demonstrated a greater increase of TF level (median: 414.5 pg/mL; range: -76.0, 6667.0) than infants without UAC-associated thrombosis (105.0 pg/mL; -976.0, 9480.0; p = 0.009) following UAC insertion. Our findings indicate that quantification and monitoring of TF levels could predict thrombus formation in infants with indwelling UAC. Following umbilical arterial catheterisation, infants with an approximately 3-fold rise in plasma TF levels were most at risk of developing abdominal aorta thrombosis as confirmed by real-time abdominal ultrasonography.
In an attempt to test the conceptual model by Lane and Terry, the purposes of this study were 1) to assess mood states in non-depressed and depressed young karate athletes; 2) to assess mood states in relation to performance in young karate athletes. The participants were recruited from the 2004 Malaysian Games (72 males, 19.20 ± 1.16 years; 37 females, 18.78 ± 0.88 years). The athletes were divided into winners (medalists) and losers. The Brunel Mood Scale (BRUMS) was administered prior to the start of competition. MANOVA was employed to treat the data, while Pearson correlations were calculated for mood states in each depressed mood group and by gender. In terms of non-depressed and depressed mood, tension in the females was higher in the depressed group (5.61 ± 3.02 vs. 3.11 ± 1.90, p = 0.026, eta(2) = 0.133), as was fatigue (3.64 ± 2.61 vs. 0.89 ± 1.69, p = 0.006, eta(2) = 0.199). Tension in the males was higher in the depressed group (4.41 ± 2.52 vs. 1.50 ± 1.55, p < 0.001, eta(2) = 0.215), as was anger (1.43 ± 1.88 vs. 0.25 ± 1.00, p = 0.019, eta(2) = 0.076). The highest associations among mood subscales were between anger and depression (r = 0.57), and between depression and fatigue ( r = 0.55) in depressed males. The female winning karateka scored higher on anger (3.08 ± 2.96 vs. 1.29 ± 2.24, p = 0.046, eta(2) = 0.109). The highest correlations between mood dimensions in depressed females were between depression and anger (r = 0.85) and between depression and confusion (r = 0.85). Contrary to previous research on the influence of depression on anger, only the female winners scored higher on anger. Several negative mood dimensions were higher in both male and female depressed groups, lending some support to the conceptual model advanced by Lane and Terry. Key PointsTo date, there is no information about the relationship between mood and martial arts performance in Malaysian athletes.There might be cultural differences in the way Malaysian athletes respond to psychological questionnaires.The mood-performance and depressed mood-non-depressed mood relationships might be mediated by age.
A variety of reconstructive options exist for revision of both femoral and acetabular components in total hip replacement surgery. The use of impaction bone grafting with morsellised allograft has shown promising results in revision total hip arthroplasty. It works as a biologic reconstitution of bone stock defects and provides a solid construct with stable fixation. We present a case of bilateral revision total hip arthroplasty with poor bone stock where reconstructive surgery was done by using impaction bone grafting, mesh and C-stem implants.
Anaemia is a frequent complication in patients with haematological malignancies and is caused by a variety of mechanisms including neoplastic cell infiltration into the bone marrow, haemolysis, nutritional deficiencies and defect in erythropoiesis or dysplastic anaemia as a result of the disease itself. However, acquired dysplastic anaemia which mimic congenital dyserythropoietic anaemia (CDA) type II morphology in the bone marrow is very rare. A 41-year-old Chinese man presented with refractory symptomatic anaemia in September 2001. He was clinically pale with no other significant physical finding. His initial peripheral blood picture showed normochromic normocytic anaemia with haemoglobin level of 26g/L, with no evidence of haemolysis and a poor reticulocyte response of 0.6%. Bone marrow aspiration was done and showed congenital dyserythropoietic anaemia (CDA) type II-like morphology. He was treated symptomatically with regular blood transfusions approximately every 3 weeks, until August 2002 when he developed multiple cervical lymphadenopathy with loss of appetite, loss of weight and low grade fever. Biopsy of the lymph node confirmed the diagnosis of small lymphocytic lymphoma. Staging with computed tomography and bone marrow aspirate revealed the infiltration of lymphoma cells into the marrow cavity consistent with the staging of IVB. This case report illustrates that CDA type II-like dysplastic anaemia can preceed the development of lymphoma.
Allogeneic bone marrow or peripheral blood stem cell transplantation traditionally uses myeloablative regimen for conditioning to enable grafting of donor's stem cells. Animal experiments have shown that a milder non-myeloablative conditioning regimen does allow engraftment to occur. Nonmyeloablative conditioning regimens are low-intensity immunosuppressive treatment given to the recipient before infusion of donor's stem cells. It was reported to have decreased immediate procedural mortality, in particular those secondary to acute graft versus host reaction. However, it did give rise to higher risks of graft rejection, tumour tolerance and disease progression. Fortunately, appropriately administered donor lymphocyte infusion has been shown to establish full donor chimerism (complete donor stem cell grafting in the recipient's bone marrow) and potentiate antitumour effect (graft versus tumour reaction). The reduction of immediate transplant mortality allows the procedure to be carried out in older age groups, patients with concomitant diseases that otherwise would have made the patients unfit for the procedure, patients with non-malignant disorders such as congenital immune deficiencies, autoimmune disorders or thalassaemia majors. The regimen also allows transplantation of genetically manipulated haemopoietic stem cells (gene thrapy) to be carried out more readily in the immediate future. Lastly, the regimen may serve as a platform for immunotherapy using specific T cell clones for anti-tumour therapy with or without the knowledge of known tumour antigen.
A new megastigmane diglycoside was isolated from the leaves of Carallia brachiata. The structure was determined by spectroscopic methods as 3-hydroxy-5,6-epoxy-beta-ionol -3-O-beta-apiofuranosyl-(1-->6)-beta-glucopyranoside (1). Additionally, 29 known compounds consisting of two megastigmanes, one 1,2-dithiolane derivative, seven aromatic compounds, five condensed tannins, 12 flavonoids, and two glyceroglycolipids were isolated and identified.
Complications that arise from self-cleaning the external ear canal are common. This is a prospective study using standard questionnaire on the practice of ear cleaning in 50 subjects. A loose tip cotton bud was also shown to them to assess if it was acceptable to replace their current cotton bud. Thirty six percent of them clean their ears by introducing an object into the ear canal once or more a day. The commonest reason to clean the ears was the presence of earwax. Only 6% used a cotton bud to mop fluid from the ear canal. Almost all (92%) the subjects used a cotton bud to clean the ear. A complication rate of 2% was noted. A loose tip cotton swab was shown to the subjects. Despite explaining that it is safer and better, only 24% of the subject were willing to change to this loose tip cotton bud. Seventy four percent of the subjects cleaned their ear regularly because of earwax. The misconception of needing to clean the ear canal by introducing an object into the ear is rampant. This practice should be avoided and health care providers can play an important role in this.
In our centre the non-availability computerized exercise machines limits the objective monitoring of strength rehabilitation. We undertook this research programme to objectively measure triceps muscle strength by interfacing NORSK-Gym machine with accelerometer and positional transducers to a computer. This data was tabulated and processed using Microsoft Excel. The positional transducer was first calibrated and it showed an excellent Pearson Correlation Coefficients against a standard metric reading (r = 0.9999). Peak Force was used as a test parameter for isotonic triceps muscle strength measurements. The criterion-referenced validity was established as the peak forces measured using the accelerometer and positional transducer demonstrated identical Peak Forces (r = 0.94). Analysis of our mean Peak Force measurements using non-biological force as well as the intra-individual reproducibility demonstrated excellent Pearson Correlation Coefficients (r) = 0.982-0.998 and 0.929-0.972 respectively. This computerized adaptation of the NORSK-Gym machine produced an objective, valid and reproducible triceps muscle strength measurement.
Rhabdomyosarcoma is a rare tumour in the middle ear and mastoid cavity in children and the diagnosis is difficult. Repeated histological examination may be essential to confirm the diagnosis. We report a 6 year old boy with a left aural polyp, otorrhoea and facial nerve palsy who was initially thought to have otitis media and mastoiditis. He had polypectomy and the tissue taken for histopathology suggested an inflammatory condition. Subsequently he had mastoidectomy. Tissue taken during mastoidectomy was however reported as rhabdomyosarcoma. The child developed a cerebral abscess and eventually succumbed. A literature review of the disease, radiological findings, immunohistochemical features and treatment options is described.