The interplay between influenza virus and host factors to support the viral life cycle is well documented. Influenza A virus (IAV) proteins interact with an array of cellular proteins and hijack host pathways which are at the helm of cellular responses to facilitate virus invasion. The multifaceted nature of the ubiquitination pathway for protein regulation makes it a vulnerable target of many viruses including IAV. To this end we conducted a yeast two-hybrid screen to search for cellular ubiquitin ligases important for influenza virus replication. We identified host protein, RING finger protein 43 (RNF43), a RING-type E3 ubiquitin ligase, as a novel interactor of nucleoprotein (NP) of IAV and an essential partner to induce NP-driven p53-mediated apoptosis in IAV-infected cells. In this study, we demonstrate that IAV leads to attenuation of RNF43 transcripts and hence its respective protein levels in the cellular milieu whereas in RNF43 depleted cells, viral replication was escalated several folds. Moreover, RNF43 polyubiquitinates p53 which further leads to its destabilization resulting in a decrease in induction of the p53 apoptotic pathway, a hitherto unknown process targeted by NP for p53 stabilization and accumulation. Collectively, these results conclude that NP targets RNF43 to modulate p53 ubiquitination levels and hence causes p53 stabilization which is conducive to an enhanced apoptosis level in the host cells. In conclusion, our study unravels a novel strategy adopted by IAV for utilizing the much conserved ubiquitin proteasomal pathway.
Exanthem subitum (ES) is a common childhood exanthematous disease. In a recent study of ES due to human herpesvirus 6 (HHV 6), we isolated human herpesvirus 7 (HHV 7) from the peripheral blood mononuclear cells (PBMC) of a seven month-old infant with typical symptoms of ES. The identity of the virus was confirmed by indirect immunofluorescence using HHV 7 specific monoclonal antibody and by amplification of the HHV 7 specific genomic sequences using the polymerase chain reaction (PCR). Paired serum samples from the infant showed serological conversion to the isolated virus. The clinical manifestations of ES in this infant appeared to be milder than the classical ES due to HHV 6.
1853 thyroid lesions subjected to cytological sampling (either by the fine needle aspiration or fine needle capillary sampling technique) from January 1992 to December 1997 at the University Hospital, Kuala Lumpur, were reviewed. Nodular goitre was the most common thyroid lesion needled (67.35%). Among the neoplastic lesions, follicular neoplasms predominated (64%), followed by papillary carcinoma (29.4%). In 325 cases, partial or total thyroidectomy had been done, providing material for histological review and cyto-histological correlation. Cytological diagnosis was found to have high sensitivity and specificity rates of over 75%. Besides, most non-neoplastic thyroid lesions could be diagnosed on cytology. The scope of cytology in the diagnosis of lymphomas, anaplastic and metastatic tumours rendered diagnostic biopsies (or thyroidectomy) unnecessary in these cases. Being a cost-effective technique and having the capacity to provide exact morphological diagnosis in a large variety of thyroid lesions, cytology is obviously the method of choice in the assessment of thyroid nodules.
The presence of serum cold agglutinin can be the initial presentation of lymphoproliferative diseases. Conditions with persistent cold agglutinins are a spectrum of diseases that vary from benign lymphoproliferation of the "autoimmune-like chronic cold agglutinin disease" to malignant lymphoma. We report a case of a 72-year-old woman who presented with severe anaemia, hepatosplenomegaly and episodes of peripheral haemagglutination precipitated by cold exposure. The haemoglobin was 5.6 g/dL with a cold agglutinin titer of 1:256 at 4 degrees C and 1:8 at room temperature (30 degrees C). The cold agglutinin showed anti-I specificity and kappa light chain restriction. Peripheral blood showed atypical lymphoid cells with a B-cell immunophenotype. Immunoglobulin gene rearrangement study by polymerase chain reaction (PCR) showed an amplified band at 100 bp, consistent with a clonal proliferation of B-lymphocytes. We believe that our patient had cold antibody haemolytic anaemia as the initial presentation of a low-grade non-Hodgkin's lymphoma. The association of cold antibody haemolytic anaemia with low-grade B-cell lymphoma is unusual.
Certain anti-idiotypic antibodies that bind to the antigen-combining sites of antibodies can effectively mimic the three-dimensional structures and functions of the external antigens and can be used as surrogate antigens for active specific immunotherapy. Extensive studies in animal models have demonstrated the efficacy of these vaccines for triggering the immune system to induce specific and protective immunity against bacterial, viral and parasitic infections as well as tumors. Several monoclonal anti-idiotype antibodies that mimic distinct human tumor-associated antigens have been developed and characterized. Encouraging results have been obtained in recent clinical trials using these anti-idiotype antibodies as vaccines. In this article, we will review the current literature and discuss the potential of this novel therapeutic approach for various human cancers.
In vitro generated cloned full length dengue 2 virus untranslated regions (UTRs) were used in RNA gel mobility shift assays to examine cellular factors binding to the virus genomes. Cellular factors in lysates of Vero (monkey) and C6/36 (mosquito) cells bound specifically and non-specifically to the dengue 2 virus 3' UTR. Non-specific interaction with the 5' UTR, resulting in formation of at least 4 band shift complexes was noted with lysate of the C6/36 cells only. Pre-treating the cell lysates with proteinase K affected binding of cellular factors to the dengue 2 virus UTRs, suggesting that the cellular factors were proteins. These findings suggest that cellular proteins could interact with specific sites on the dengue virus genomes.
Systemic lupus erythematosus (SLE) is an autoimmune disease characterised by increased B cell activity and depressed T cell function. However, the contribution of the immunoregulatory system to its pathogenesis is still unclear. The recent development in the production of monoclonal antibodies and the availability of bench-top flow cytometers have allowed rapid quantitation of peripheral blood lymphocyte subsets. We analysed the distribution of the lymphocyte subsets in 24 patients with active SLE and 18 with inactive SLE. The distribution of immunoregulatory cells in 72 normal volunteers was used as control. Statistical analysis showed that there were significant differences between both the SLE groups and the normal controls, for total lymphocytes, T cells, B cells, T helper cells, T suppressor cells, T helper/suppressor ratio and natural killer cells. There was a significant difference for T helper cells between active and inactive SLE. T helper cells levels were found to be low in inactive SLE and lower in active SLE. It appears that treatment-induced remissions did not restore the levels of immunoregulatory cells to normal. Thus, T helper cell levels reflect disease activity and longitudinal assays of T helper cells may serve as an indicator of disease reactivation.
Postal surveys are becoming an increasingly popular method of conducting research in Malaysia. However, the response rates from these surveys have not been well studied. All postal surveys published in the Medical Journal of Malaysia between 1991-2000 were therefore reviewed to provide an overview of the response rates that may be expected, and to assess if this is a valid method of conducting research here. The response rates of postal surveys ranged from 30-87.5%. Seven of 13 postal surveys (54%) had a response rate of less than 50% and only 2 of 13 (15.4%) had a response rate of more than 70%, raising doubts on the use of postal surveys as a research tool.
Studies were carried out in T-flasks and bioreactor to produce urokinase enzyme using HT 1080 human kidney cell line. While growing the cell line it has been observed that the lag phase is reduced considerably in the bioreactor as compared to T-flask culture. The HT 1080 cell adhesion rate and urokinase production were observed to be the function of serum concentration in the medium. The maximum urokinase activity of 3.1 x 10(-4) unit ml(-1) was achieved in the bioreactor at around 65 h of batch culture. Since HT 1080 is an anchorage dependent cell line, therefore, the hydrodynamic effects on the cell line were investigated.
The effect of L-asparaginase on the thyroid gland has not been well documented. We report the first two cases of hyperthyroidism associated with thyroid nodule following L-asparaginase therapy for acute lymphoblastic leukemia (ALL). The thyroid function abnormalities were not severe, short-lived and did not require specific therapy.
A 56-year-old Chinese lady with valvular heart disease and atrial fibrillation was referred to us from a private hospital for further management of autoimmune haemolytic anaemia. Physical examination and laboratory investigations did not support the diagnosis of haemolytic anaemia. However, direct antiglobulin test (DAT) was strongly positive with anti-IgG and negative with anti-C3d. There was also mild anaemia and reticulocytosis, which was attributable to persistent haematuria. The DAT became positive after commencing Unasyn and cessation was associated with decreasing reactivity of the positive DAT. We believe that the positive DAT in this patient was most likely due to the Unasyn therapy.
With the advent of new monoclonal antibodies that are applicable to formalin-fixed, paraffin embedded sections, immunophenotyping is becoming increasingly important in the diagnosis and classification of lymphomas. However, multiple factors such as fixation, trypsinization and even type of antibodies used have certain effects on the final outcome of the staining procedure. In this paper we report our experience and the problems encountered in our laboratory when we first tried to establish a workable immunostaining protocol for formalin-fixed, paraffin embedded tissue sections using the immunoalkaline phosphatase technique.
This study aimed to determine the role of surfactant protein A (SP-A) in the formation of stable microbubble in tracheal aspirates. Our results showed that as the concentration of anti SP-A antibodies added to tracheal aspirate specimens increased, the number of stable microbubble formed in the specimen decreased. The correlation between stable microbubble counts and the SP-A levels in the tracheal aspirates was good, r = 0.85, p < 0.05. This study suggests that SP-A plays an important role in stable microbubble formation. Measurement of small stable microbubbles is thus a useful bedside test for predicting the SP-A activity in the tracheal aspirates and in indirect measurement of lung maturity.
Anaesthesia for the separation of conjoined twins requires a well-prepared, multidisciplinary team. Each patient for surgery is different and the extent of organ sharing and coexisting anomalies must be determined before surgery so that problems can be anticipated. We report our experience of the anaesthetic management for the separation of six sets of conjoined twins. Anaesthesia and surgery were prolonged, massive blood loss and transfusion, hypothermia, electrolyte imbalance and infection being the main perioperative problems encountered.
The limited sequencing approach was used to study the molecular epidemiology of 24 Malaysian dengue 2 viruses which were isolated between 1968 and 1993. The sequences of a 240-nucleotide-long region across the envelope/non-structural 1 protein (E/NS1) gene junction of the isolates were determined and analysed. Alignment and comparison of the nucleotide and deduced amino acid sequences of the isolates revealed that nucleotide changes occurred mostly at the third position of a particular codon and were of the transition (AG, CU) type. Five nucleotide changes resulted in amino acid substitutions. Pairwise comparisons of the nucleotide sequences gave divergence values ranging from 0 to 9.2%. At the amino acid level, the divergence ranged between 0 and 3.8%. Based on the 6% divergence as the cut-off point for genotypic classification, the isolates were grouped into two genotypes, I and II. Comparison of the nucleotide sequences of the Malaysian dengue isolates with those of the dengue viruses of other regions of the world revealed that members of genotypes I and II were closely related to viruses from the Indian Ocean and Western Pacific regions, respectively.
Primary lymphangiomyomatosis is a benign tumour of lymphatic channels and lymph nodes, clinically manifested by chylous ascites. This disease is usually progressive and unresponsive to surgery, chemotherapy or irradiation. A case of a 36-year-old lady with chylous ascites due to underlying primary lymphangiomyomatosis is reported.
All-trans retinoic acid therapy induces maturation in acute promyelocytic leukaemia. We document in vivo evidence of differentiation by all-trans retinoic acid in a case of acute promyelocytic leukaemia which was characterized by cytoplasmic vacuolations.